RC 1

In this study Charton et al. carried out a high-resolution pollen analysis of the penultimate glaciation part of a marine core from the Alboran Sea. The authors discussed the pollen data and deduced vegetation changes and climate inferences and compared them to other paleoclimatic records from the study area making some interesting inferences. Detailed records from the MIS6 glaciation in the western Mediterranean are quite rare so that adds interest to this study.  

I suggest publication in Egusphere but some changes should be done before publication. Here below are my comments:

-Line 43: This sentence is not clear - explain this further.

Corrected to “A synthesis of human occupation during MIS 6 shows that a mosaic of traditional (Mode 2) and innovative (Mode 3) lithic technological features is observed in the archaeological record.”

-Line 44: in plural: neanderthals seem to have..

Corrected

-Line 128: be more specific?

Corrected “This record from the deep-sea core MD01-2444 showed that several D-O-like events impacted the vegetation during the lower part of MIS 6 (Margari et al., 2010).”

We cannot be much more specific as the study didn’t focus specifically on vegetation changes.

-Line 136: chose a better word than connect. relate? correlate?

Corrected as “correlate”

-Line 157: Not really a climate reference for the study area

Reference changed to

Sánchez-Laulhé, J. M., Jansa, A., & Jiménez, C. (2021). Alboran Sea Area Climate and Weather. In J. C. Báez, J.-T. Vázquez, J. A. Camiñas, & M. Malouli Idrissi (Eds.), Alboran Sea—Ecosystems and Marine Resources (pp. 31–83). Springer International Publishing. https://doi.org/10.1007/978-3-030-65516-7_3

-Line 165: Picea does not grow naturally in the study area

Picea was cancelled.

-Line 169: The Atlantic currents? which ones? can you be more specific for your study site?

Corrected to “the surface Atlantic waters”

-Line 194: add: correlation to orbital configuration

Sentence changed to “For the lower interval, the low resolution of planktonic isotopic data available for ODP 976 did not allow direct correlation to global temperature stacks or orbital configuration”

-Line 199: The chronological control of the sequence is based on direct correlation to very distant and various records, such as a speleothem in China and a record from the coast off Portugal, which in turn was aligned to the Antarctic temperature record (even considering the bipolar seesaw...) ...the authors then assumed that vegetation changes in the Mediterranean were synchronous to Chinese and Antarctic temperatures. There is a possibility that this can be true but this approach limits the output in terms of lags or leads of the response of the vegetation in your record to climate events worldwide...

Thank you for this relevant comment which calls for more clarity in the justification of our chronological approach.

Tuning between the benthic oxygen isotope record in the Atlantic (core MD01-2444) and the Antarctic temperature record is justified in details in Margari et al. (2010). It has been shown in a large number of studies for the last climatic cycle that if the planktonic oxygen isotope record is closely linked to the northern polar temperature record, the benthic oxygen isotope is better related to the Antarctic temperature record, accounting for the bipolar seesaw effect.

Tuning between the Alboran Sea SST and speleothems in Italy and in China has been justified in details in Jiménez-Amat & Zahn (2015). A close connexion between North Atlantic and Mediterranean paleoclimate and Asian monsoon following millennial-scale oscillations has been evidenced for the last climatic cycle (e.g. Kelly et al., 2006; Tzedakis et al., 2018). The assumption can be made that this relation was applicable during the previous climatic cycle, and therefore during MIS 6.

We are aware of the limitations of these tuning approaches, which can lead to circular interpretations and have to be used with caution. The main assumption is that millennial climate changes including D-O-like cycles during the Penultimate glacial resulted in an immediate response of the Alboran Sea environments (marine environment for the 125-142 ka interval, and continental environment for the 142-200 ka interval). These assumptions are discussed in more details in the original publications on which our chronology is based (Jiménez Amat & Zahn, 2015; Margari et al., 2010; Shin et al., 2020). It is impossible, based on our chronological tuning, to assess the timing of the vegetation response to the global climate events, and this question is therefore outside of the scope of this paper. Despite these limitations, this approach remains the most valuable for chronological tuning of the core in absence of radiometric dating.

We propose to acknowledge this limitation more explicitly in the Age model methods by adding two sentences: “The main assumptions of these tuning approaches with Dongge cave speleothem and the Antarctic record are discussed in details in Jiménez-Amat and Zahn (2015) and Margari et al. (2010) respectively. The obtained chronology for ODP 976 core for MIS 6 prevents any assessment of the southwestern Mediterranean vegetation response to global climatic events.”

For example, in lines 402-403: How is it possible to observe a delay for TII in your record if the chronology was tuned to that particular speleothem record? If there is not an objective direct chronological control of your core you cannot really discuss about this matter

Our record was tuned to the speleothems based on the SST record, and therefore we cannot indeed discuss the delay between TII in the speleothems and in our marine record. In this sentence however, we discuss the delay of the vegetation response to Termination II in our record, compared to the marine indicators. We only imply that an offset response to TII is observed between the marine and terrestrial proxies in the Alboran Sea record.

We added a sentence to clarify this point: “This delay in marine and terrestrial proxies may reflect the vegetation response to the first cold pulse of HS11.”

-Line 215: change "here" for "In this study"

Done

-Line 224: Change "along" for "in"

Done

-Line 234: remove "As already pointed out,"

Done

-Figure 3. I imagine this figure was meant to be represented horizontally. However, vertically the numbers in the scales are upside down and should be rotated 180º.

Done

-Lines 294-314. In this section, the results are already interpreted in terms of climate - I would leave those interpretations for the discussion and just describe the results here

Done

-Line 303: Ericaceae rather indicates humid conditions, not cold climate

It is true that moisture is the most important climatic parameter for Ericaceae. However, our interpretation is also based on the fact that Ericaceae were one of the main vegetation components during the Last Glacial Maximum in the Alboran Sea (see Combourieu-Nebout et al., 2009). We removed “cold” to avoid confusion.

-Line 341: Present-day climatic conditions are shown in Figure 5 by stars -  are those from the location of the marine site? from any other specific location? please specify

These values are extracted from ERA 5 climate-model reanalysis, between 1960-2022 and correspond to a 400 km average around the site, as described in the methods section. We added a sentence in the figure’s legend for clarity.

-Line 341: Remove "all along" and change it for "during"

Done

-Figure 5 and text: The substages MIS6e-a were defined in an isotopic record but do not seem to agree with the results here - why do you pay so much attention to that?

The isotopic stages and substages defined by Lisiecki & Raymo (2005) and then refined by Railsback et al. (2015) are widely used as a reference for paleoclimate studies, including MIS 6. In the main studies concerning MIS 6, such as Margari et al. (2011, 2014) or Sinopoli et al. (2019), this nomenclature is also used as a reference, although the different proxies do not always align with the isotopic subdivision. It is indeed true that our climate results do not fit exactly with the five isotopic substages (MIS 6a-b), however they are not completely divergent either: our zone 1 roughly correspond to MIS 6e-d, zone 2 to MIS 6c-b, and zones 3-4 to MIS 6a. As already pointed out for the last glacial period (e.g. Combourieu-Nebout et al., 2002, 2009; Masson-Delmotte et al, 2005; Genty et al., 2005), the vegetation and climate record of the Alboran Sea is influenced by both long-term (i.e. orbital) variability as also reflected in the reference isotopic subtages (MIS 5-1), and short term (i.e. millennial-scale) variability. Therefore, we believe it is still useful to discuss our results for MIS 6 in the frame of the reference oxygen isotopic nomenclature for clarity and to point out their differences and similarities.

-Fig. 5 legend: it is a black star (not red)

Done

-Lines 380-381. This sentence is too vague...the pollen results do not really agree with the MIS6 glacial substages (a-e) and/or D-O dynamics that are only defined for the last glaciation...maybe it would be better to say "D-O-like dynamics" and I would remove the glacial substages.

The pollen zones do partially agree with the glacial substages, as previously said and explained in the discussion. Differences in the temporal resolution and chronological control for the period might also affect the correlation between pollen/climate record and the isotopic substages. We think it is still useful to keep the reference isotopic framework for comparison with our record. Finally, the text already mentioned “D-O-like dynamics”, as indeed there is no reference chronostratigraphic framework for D-O events during MIS 6 yet.

-Lines 382-391: As these three phases don't coincide with the previously defined substages, I would remove those from the text and add ages when those phases occur in your record

As already mentioned, the three phases do correspond roughly to MIS 6 e-d, MIS 6 c-b, and MIS 6 a and we think it is useful to keep the isotopic reference framework.

However, we take in consideration your comment and propose the following changes: 1) adding the ODP 976 pollen zones to the figures for comparison with the isotopic subdivision, and 2) indicating the approximative dates of the pollen zones at the beginning of the discussion.

-Line 402-403. Please give the ages for the beginning and end of the termination II in your record and describe how you identified that termination in the ODP 976 pollen record

The ODP 976 marine record is tied to Dongge cave chronology, as detailed in the chronology section of the methods (section 3.2). The timing for TII in our record, based on marine indicators, is therefore the same as the weak Asian monsoon event during HS11. We added a sentence to insist on that point.

That being said, the following sentences refer strictly to the vegetation response to TII in our record, which is different and a bit delayed compared to the marine indicators.  

-Line 407: W?

Done

-Line 413: Do you mean the abrupt drop of temperatures at the beginning of HS11?

Yes. We added that precision to the sentence.

-Line 416: I would rather call this section "Hydroclimate connection..."

Done

-In Figure 3. Pioneer vegetation is represented by brown color, as Ericaceae here. Please be consistent and use the same color for the different categories in all figures

Thank you for this helpful comment. Colours were adjusted for Ericaceae and pioneer vegetation in Fig. 3.

-Line 455: Could you please explain why deciduous forest is important in better noticing the MIS7-6 transition? 

In the Eastern Mediterranean sites, a higher contrast has been described between interglacial periods with very high percentages of temperate deciduous forest taxa and glacial periods with very reduced tree cover (Tzedakis, 1993; Tzedakis et al., 2006). The western Mediterranean region, at the contrary, was generally characterized by a high proportion of herbaceous taxa, even during interglacial periods, attenuating the vegetation contrasts during transitions to glacial periods.  This trend is particularly visible in our figure for the MIS 7-6 transition.

-Lines 477-486. Maybe representing site MD01-2444 in Figure 6 would be usefull, even though it is not a Mediterranean site "per se", it looks like ODP 976 share a lot of similarities with it

We completely agree with your important suggestion. Unfortunately, the complete pollen data from MD01-2444 site are not publicly available. However, we added the two public curves of temperate and Mediterranean pollen taxa to the figure (although they were already shown in Fig. 7).

-Lines 481-486: Could it be due to lower summer insolation generating lower evaporation in summer and favouring the growth of Ericaceae, which requires humidity throughout the year?

Yes, this explanation was particularly developed by Fletcher & Sanchez Goni (2008) and can be applied here. We added this reference to strengthen this interpretation.

-Line 498: I would just say Moroccan Mountains - Cedrus could also originate from the Atlas

Done

-Line 505: Change across for throughout

Done

-Line 507: Not just rapid, but enhanced development of forest in that area

Done

-Line 508: Please explain why altitude is important here

Thank you for this relevant suggestion. We modified and completed our discussion as follows:

“This pattern of enhanced and rapid variations in tree cover at Tenaghi Philippon was already described during the last climatic cycle and reflects the exacerbated vegetation dynamics locally, with episodes of rapid and enhanced colonization by tree vegetation (Koutsodendris et al., 2023; Tzedakis, 2005; Tzedakis et al., 2004). This has been mainly explained by the location of the site in a low altitudinal plain characterized by a more continental climate with lower winter precipitation: tree population at lower altitudinal location are closer to their ecological threshold in term of precipitations, and are likely to be very affected even by minimal changes in the amount of rainfall.”

-Line 523: Please be more specific of why do you think it is compatible with DO-like variabilty. Is it the duration of the events? the intensity?

Yes, at first look they look like D-O events based on the vegetation dynamics, timing and intensity. Following your comment we added that precision to the sentence. “Finally, all palynological sequences reveal high-frequency oscillations of temperate and semi-desert pollen, compatible at first look with DO-like variability based on their duration and intensity.”

Then in section 5.5 we discuss their differences with the last glacial.

-Line 527: What does "disentangle the character" mean? investigate?

Yes, we replaced this word by “investigate”.

-Line 529. What do you mean with consistent? similar? in what? time? intensity? be more specific

Thank you for this comment. We changed the sentence as follows: “The events of arboreal pollen increase observed in the ODP 976 record show percentages and timing comparable to those from the Portuguese margin core MD01-2444 (Margari et al., 2010, 2014; Tzedakis et al., 2018) (Fig. 7, m).”

-Line 532: Remove "the" and change it for "its more semiarid"

Done

-Line 434. Confirm this, as earlier you said Ericaceae was a "cold" indicator (see line 303) - be consistent

Thank you for this comment.

Ericaceae show an ambiguous pattern when looking at both long-term and high-frequency patterns. They are connected to D-O events through the Atlantic influence on moisture availability (e.g. Fletcher & Sanchez Goni, 2008), but they are also a major component of the vegetation at time of glacial maximum like the LGM (Combourieu-Nebout et al., 2009). However, to avoid confusion and to be consistent we removed their qualification as “cold” indicators earlier.

-Line 539. This affirmation is very vague. There are significant differences between the Cueva Gitana and ODP 976, for example maximum humidity seems to occur at 148 kyr, which is not replicated in your record 

This is true and we therefore bring clarification on this point.

The maximum humidity at Cueva Gitana ~150 ka is not replicated in our record, but at that time we find several moderate increases of temperate forest pollen, and the climate reconstructions show a progressive amelioration from then. The differences between the two records are likely due to the different representativeness of the climatic signal between a speleothem, which mainly depends on local hydroclimate conditions, and a marine core which records regional climatic conditions. Considering these premises, we think that the two records generally show consistent trends. The records are not completely similar when looking into details, but this is also the case for SSTs, and also depends on the different time resolution and calibration applied to the different records.

We slightly modified our sentence to address the correlation between pollen-based climate reconstructions, SST and speleothem records with more caution: “The ODP 976 pollen-inferred climate reconstructions show generally consistent patterns with the SSTs trends based on alkenones (Martrat et al., 2004, 2007), and the southern Iberian humidity recorded in the speleothem from Cueva Gitana (Hodge et al., 2008) (Fig. 7).”

-Fig. 7. The text of the legends of the different plots should be written in a bigger size. 

Also, the scale in the synthetic pollen figure from ODP 976 is missing 

In addition, the pollen data do not really agree with the substage subdivision done by Railsback fro MIS 6 - I would remove that subdivision.

Thank you, we made the relevant modifications on the figure.

We kept the isotopic substages as explained before, but we addressed your suggestion by also adding the ODP 976 pollen zones for comparison on the figure.

-Lines 566-572: This paragraph is repetitive, see the beginning of the discussion in lines 382-415. I would remove it or synthesize those two paragraphs in one. Also, check more text in this section for further repetition

We moved these few sentences at the beginning of the first discussion section, where we describe the three phases during MIS 6.

-Lines 573-583. Check for repetitions in the sapropel discussion with the previous section about the ORLs - this could be synthesized...maybe adding the ORL text in this section?

We agree with you that some parts may sound repetitive.

However, we consider it is important to separate in discussion 1) a first short introduction to the presence of ORLs in our western Mediterranean record (which are less known than Sapropels) and their comparison with vegetation and climate results in the same core, and 2) a wider interpretation of hydroclimatic conditions integrating our record with other regional and global references.

-Line 589. How do the isotopic and sea surface temperature records reflect precipitation? Please explain

In this study, the isotopic and SST records are used to reconstruct surface water isotopic composition, which is a proxy for past salinity and is directly dependant on precipitation.

We added that precision to the sentence: “Higher pluviometry is supported by foraminifera isotopic and SSTs signal throughout the Mediterranean Sea, which were used to reconstruct past salinity and freshwater budget regionally”.

-The size of figure 9 as it is shown in the pdf here is too small - one can barely read the text-numbers so it should be bigger.

Done

-Line 903: replace "consistent with" with similar to

Done

-Line 917: Change "double u for "W"

Done

RC2

Revision Charton et al. (2025)

The study by Charton et al. (2025) presents new high-resolution pollen data and quantitative reconstructions of temperature and precipitation, which have been used to relate it to previous archaeological interpretations concerning human populations during MIS 6–5. Thanks to the high-resolution pollen analysis carried out (200 samples), the authors have also been able to explore short and intense paleoclimatic periods, such as the HS11. Therefore, despite certain issues described below in the section “Major comments,” the study provides valuable data and interesting multidisciplinary interpretations, making it a noteworthy contribution to the scientific community, and deserves publication after major revisions.

Major comments:

One of the main issues concerns the chronology of the studied core, which relies on correlations with other records through tie-points. Independent chronological control in marine archives for ages above the radiocarbon dating limit has been a common challenge in paleoclimate studies. However, in this case, the correlation of the studied core with the marine record MD01-2444, which also lacks independent age control and chronology, and which in turn is aligned with the Greenland δD record (Dome C ice-core), is problematic. This situation may lead to paleoclimatic reconstructions being subject to circular reasoning. Since the chronological framework represents one of the weaknesses of this study, it would be necessary to present the age alignments more explicitly to the reader, for example, by showing the depth correlations from the onset of MIS 6 to the present between the studied record and MD01-2444, as well as the tie-points linking MD01-2444 with the Greenland core. By showing the depth correlations for the last 200 ka together with the absolute ages (displayed alongside the depth axis) of records that are independently dated (in this case, the Antarctic Dome C ice-core), the reader can understand that the tie-points used here are potentially robust and that these alignments correspond to the same climatic variations of the penultimate glacial period. Similarly, no correlation graph is presented between the ODP 976 core and the Chinese speleothem records from Dongge Cave.

Thank you very much for this relevant comment on which we mostly agree. We are of course aware of the limitations of the tuning approach used for age calibration of the ODP 976 record, which can lead to circular interpretation of the paleoclimate signal if not taken carefully. However, in absence of any direct chronometric dates, the indirect paleoclimatic tuning is the best approach generally used for chronological calibration of marine cores, and we do not think it is “problematic”, if well-presented and justified. We therefore acknowledge the further need for justification and details on the chronological tuning approach.

We are unable to provide the correlation between ODP 976 and MD01-2444 records from MIS 6 to the present, as the pollen data from core MD01-2444 are not publicly available, and studies are still ongoing. We can therefore only provide the correlation between temperate pollen from the two cores between 195 and 125 ka as already shown in Fig. 2. Besides, the tie-points of core MD01-2444 benthic isotopic record to Epica Dome C are taken directly from Shin et al. (2020), based on the AICC2012 chronology (Bazin et al., 2013). We added a new supplementary table including the tie-points between core MD01-2444 and EDC (11 tie-points, between 135 and 195 ka, taken from Shin et al., 2020), and Corchia cave (7 tie points between 126-139 ka, taken from Tzedakis et al, 2018).

Regarding the correlation between ODP 976 SSTs and speleothem records, the alignment was already presented in Jiménez Amat & Zahn (2015). We added a supplementary figure to show the graphical correlation between the three records with the tie-points taken from the original publication.

We hope that these supplementary files, as well as more explicit reference to the original publications justifications and limitations (see response to Reviewer 1), can bring clarification and transparency to our approach.

Regarding the quantitative reconstructions, the authors should provide a clearer specification of the modern pollen training set used for the reconstructions. It is indicated that the dataset of Peyron et al. (2013, 2017) and updated by Dugerdil et al. (2021) and Robles et al. (2023) was employed. However, it is essential to include the total number of harmonized taxa used for reconstructions and should also mention any taxa that have been excluded, for example, aquatics. It would also be helpful to show a map displaying the location of all the modern samples used. They should also specify the area, including the latitude and longitude of this training set. It would also be useful to see the maximum bias for each method in Table 3. To better understand which taxa are responsible for the changes observed in the reconstructions, I also suggest including a figure showing the tolerance spectra of the main pollen taxa for each of the climatic parameters used (MAAT, MTCO, TCON, MAP, WINTERRR, PCON).

Thank you for these very helpful suggestions. All the required details have been added in the text, and we included a map of the modern pollen dataset in the Supplements (Fig. S2). We also added an additional figure in Supplements showing the tolerance spectra of the main pollen taxa to the six climate parameters reconstructed (Fig. S3). A small paragraph has been added on this matter:

 “The climatic tolerance spectra of the ten most abundant pollen taxa in the ODP 976 record have been reconstructed based on the modern dataset (Supplement, Fig. S3). They show shat steppe and semi-desert taxa display the highest tolerance to low winter temperature and precipitation, while Mediterranean taxa (Olea and Quercus ilex-type) are the most tolerant taxa to high annual and summer temperature, and Cedrus and Ericaceae to higher annual and seasonal precipitation.”

Finally, the best R2 and RMSE values for each method has been shown in bold in Table 3.

At the end of section 5.1, a delay of around 1000 years is mentioned with respect to the marine SST of ODP 976 (Jiménez-Amat and Zahn, 2015; Martrat et al., 2014). Considering that this is the same record, why does this delay occur? Is this due to a delay in the continental response compared to that recorded in the sea? Is the age model of Jiménez-Amat and Zahn (2015) and Martrat et al. (2014) based on the same tie-points as this study, and therefore the age chronology is the same? If not, then referring to a delay of only 1,000 years when dealing with interpretations for MIS 6, and considering that the chronological control is not independent and relies on correlations between warm events, appears at the very least, risky and potentially overinterpreted.

Our age model uses the same tie-points than Jiménez Amat & Zahn (2015). Regarding the ~1000 years delay, it corresponds to a delay in the vegetation response to cold water entrance. When looking at the ODP 976 SST record, cold temperatures start at ~134.5 ka, while steppe and semi-desert pollen peak only at ~133.3 ka (start of pollen zone 4).

We added a sentence to clarify this point: “This delay in marine and terrestrial proxies may reflect the vegetation response to the first cold pulse of HS11.”

In section 5.4, the authors analyze the HS11 signal in OPD 976 and other records. Although they mention the difference in intensities recorded between the eastern and western Mediterranean, they do not delve into the climatic mechanisms that could have led to this difference between the two areas.

Thank you for this relevant comment. We discussed further this point as follows: “This observation is compatible with previous observations that Heinrich stadials during the last glacial had a minor impact on the eastern Mediterranean vegetation compared to the western Mediterranean, likely due to the already limited presence of tree vegetation in the eastern records during glacials (Tzedakis, 2005). A similar interpretation can be proposed for the differential response of eastern and western Mediterranean vegetation to HS11, supporting the major sensitivity of the southwestern Mediterranean vegetation to North Atlantic cold events.”

Minor comments:

In Methods, I suggest including the average resolution of pollen samples in age. Taking into account the beginning (195.72 ka BP) and end of the record (127.47 ka BP), and the 200 pollen samples analyzed, the average resolution should be approx. 341 years/sample. Please verify this.

Yes, this indication was already mentioned at line 205 in the age model methods.

Mention the meaning of “mcd” when it first appears in Table 1 or in Line 215, not in Figure 3.

Corrected.

Explain why a radius of 400 km is used to calculate the average value of climate parameters. Pollen influence is reduced beyond a radius of 175 km (Rojo et al., 2016). However, other studies suggest that pollen can be transported up to distances of 200-300 km (Fernández-Rodríguez et al., 2014), and even over distances greater than 500 km (Bayr et al., 2023; Bogawski et al., 2019). The authors could use some of these studies to explain the radius used to obtain the recent average values.

Thank you very much for this suggestion. We modified the paragraph as follows: “Pollen dispersal is reduced beyond a radius of 175 km (Rojo et al., 2016). However, other studies suggest that pollen can be transported up to distances of 200-300 km (Fernández-Rodríguez et al., 2014) and even over distances greater than 500 km (Bayr et al., 2023; Damialis et al., 2017). Sediments from marine cores such as ODP 976 can therefore include close and long-distance pollen. To account for these observations, an averaged value of the climate parameters on a 400 km radius around the ODP 976 site was extracted.”

Lines 263-266: Authors should mention the total number of harmonized taxa that compose the training set.

Changed to “A total of 103 harmonized pollen taxa are included in the dataset, excluding Pinus and aquatic taxa”

Line 300: “Jeanne Rampal, personal communication”. Provide the age of the communication.

Done (2023).

Lines 872 and 917: Use HS11 instead of “Heinrich Stadial 11”

Done.

Figure 6: Explain why Pinus was included as pioneer vegetation in Ioannina and why it was not included in other records.

Pinus was included in pioneer vegetation at Ioannina, as it is the only record where Pinus is not over-represented. This precision was added in Fig. 6 legend.

To facilitate reading between the text and the figures, I suggest including the letters of the curves when referring to a record in a figure, especially when referring to records in Figure 7.

 Done.

New references cited:

Rojo, J. et al. Modeling olive pollen intensity in the Mediterranean region through analysis of emission sources. Science of The Total Environment 551-552, 73-82 (2016).

Fernández-Rodríguez, S. et al. Identification of potential sources of airborne Olea pollen in the Southwest Iberian Peninsula. International Journal of Biometeorology 58, 337-348 (2014).

Bayr, D. et al. Pollen long-distance transport associated with symptoms in pollen allergics on the German Alps: An old story with a new ending? Science of The Total Environment 881, 163310 (2023).

Bogawski, P., Borycka, K., Grewling, Ł. Kasprzyk, I. Detecting distant sources of airborne pollen for Poland: Integrating back-trajectory and dispersion modelling with a satellite-based phenology. Science of The Total Environment 689, 109-125 (2019).

 RC 1

In this study Charton et al. carried out a high-resolution pollen analysis of the penultimate glaciation part of a marine core from the Alboran Sea. The authors discussed the pollen data and deduced vegetation changes and climate inferences and compared them to other paleoclimatic records from the study area making some interesting inferences. Detailed records from the MIS6 glaciation in the western Mediterranean are quite rare so that adds interest to this study.  

I suggest publication in Egusphere but some changes should be done before publication. Here below are my comments:

-Line 43: This sentence is not clear - explain this further.

Corrected to “A synthesis of human occupation during MIS 6 shows that a mosaic of traditional (Mode 2) and innovative (Mode 3) lithic technological features is observed in the archaeological record.”

-Line 44: in plural: neanderthals seem to have..

Corrected

-Line 128: be more specific?

Corrected “This record from the deep-sea core MD01-2444 showed that several D-O-like events impacted the vegetation during the lower part of MIS 6 (Margari et al., 2010).”

We cannot be much more specific as the study didn’t focus specifically on vegetation changes.

-Line 136: chose a better word than connect. relate? correlate?

Corrected as “correlate”

-Line 157: Not really a climate reference for the study area

Reference changed to

Sánchez-Laulhé, J. M., Jansa, A., & Jiménez, C. (2021). Alboran Sea Area Climate and Weather. In J. C. Báez, J.-T. Vázquez, J. A. Camiñas, & M. Malouli Idrissi (Eds.), Alboran Sea—Ecosystems and Marine Resources (pp. 31–83). Springer International Publishing. https://doi.org/10.1007/978-3-030-65516-7_3

-Line 165: Picea does not grow naturally in the study area

Picea was cancelled.

-Line 169: The Atlantic currents? which ones? can you be more specific for your study site?

Corrected to “the surface Atlantic waters”

-Line 194: add: correlation to orbital configuration

Sentence changed to “For the lower interval, the low resolution of planktonic isotopic data available for ODP 976 did not allow direct correlation to global temperature stacks or orbital configuration”

-Line 199: The chronological control of the sequence is based on direct correlation to very distant and various records, such as a speleothem in China and a record from the coast off Portugal, which in turn was aligned to the Antarctic temperature record (even considering the bipolar seesaw...) ...the authors then assumed that vegetation changes in the Mediterranean were synchronous to Chinese and Antarctic temperatures. There is a possibility that this can be true but this approach limits the output in terms of lags or leads of the response of the vegetation in your record to climate events worldwide...

Thank you for this relevant comment which calls for more clarity in the justification of our chronological approach.

Tuning between the benthic oxygen isotope record in the Atlantic (core MD01-2444) and the Antarctic temperature record is justified in details in Margari et al. (2010). It has been shown in a large number of studies for the last climatic cycle that if the planktonic oxygen isotope record is closely linked to the northern polar temperature record, the benthic oxygen isotope is better related to the Antarctic temperature record, accounting for the bipolar seesaw effect.

Tuning between the Alboran Sea SST and speleothems in Italy and in China has been justified in details in Jiménez-Amat & Zahn (2015). A close connexion between North Atlantic and Mediterranean paleoclimate and Asian monsoon following millennial-scale oscillations has been evidenced for the last climatic cycle (e.g. Kelly et al., 2006; Tzedakis et al., 2018). The assumption can be made that this relation was applicable during the previous climatic cycle, and therefore during MIS 6.

We are aware of the limitations of these tuning approaches, which can lead to circular interpretations and have to be used with caution. The main assumption is that millennial climate changes including D-O-like cycles during the Penultimate glacial resulted in an immediate response of the Alboran Sea environments (marine environment for the 125-142 ka interval, and continental environment for the 142-200 ka interval). These assumptions are discussed in more details in the original publications on which our chronology is based (Jiménez Amat & Zahn, 2015; Margari et al., 2010; Shin et al., 2020). It is impossible, based on our chronological tuning, to assess the timing of the vegetation response to the global climate events, and this question is therefore outside of the scope of this paper. Despite these limitations, this approach remains the most valuable for chronological tuning of the core in absence of radiometric dating.

We propose to acknowledge this limitation more explicitly in the Age model methods by adding two sentences: “The main assumptions of these tuning approaches with Dongge cave speleothem and the Antarctic record are discussed in details in Jiménez-Amat and Zahn (2015) and Margari et al. (2010) respectively. The obtained chronology for ODP 976 core for MIS 6 prevents any assessment of the southwestern Mediterranean vegetation response to global climatic events.”

For example, in lines 402-403: How is it possible to observe a delay for TII in your record if the chronology was tuned to that particular speleothem record? If there is not an objective direct chronological control of your core you cannot really discuss about this matter

Our record was tuned to the speleothems based on the SST record, and therefore we cannot indeed discuss the delay between TII in the speleothems and in our marine record. In this sentence however, we discuss the delay of the vegetation response to Termination II in our record, compared to the marine indicators. We only imply that an offset response to TII is observed between the marine and terrestrial proxies in the Alboran Sea record.

We added a sentence to clarify this point: “This delay in marine and terrestrial proxies may reflect the vegetation response to the first cold pulse of HS11.”

-Line 215: change "here" for "In this study"

Done

-Line 224: Change "along" for "in"

Done

-Line 234: remove "As already pointed out,"

Done

-Figure 3. I imagine this figure was meant to be represented horizontally. However, vertically the numbers in the scales are upside down and should be rotated 180º.

Done

-Lines 294-314. In this section, the results are already interpreted in terms of climate - I would leave those interpretations for the discussion and just describe the results here

Done

-Line 303: Ericaceae rather indicates humid conditions, not cold climate

It is true that moisture is the most important climatic parameter for Ericaceae. However, our interpretation is also based on the fact that Ericaceae were one of the main vegetation components during the Last Glacial Maximum in the Alboran Sea (see Combourieu-Nebout et al., 2009). We removed “cold” to avoid confusion.

-Line 341: Present-day climatic conditions are shown in Figure 5 by stars -  are those from the location of the marine site? from any other specific location? please specify

These values are extracted from ERA 5 climate-model reanalysis, between 1960-2022 and correspond to a 400 km average around the site, as described in the methods section. We added a sentence in the figure’s legend for clarity.

-Line 341: Remove "all along" and change it for "during"

Done

-Figure 5 and text: The substages MIS6e-a were defined in an isotopic record but do not seem to agree with the results here - why do you pay so much attention to that?

The isotopic stages and substages defined by Lisiecki & Raymo (2005) and then refined by Railsback et al. (2015) are widely used as a reference for paleoclimate studies, including MIS 6. In the main studies concerning MIS 6, such as Margari et al. (2011, 2014) or Sinopoli et al. (2019), this nomenclature is also used as a reference, although the different proxies do not always align with the isotopic subdivision. It is indeed true that our climate results do not fit exactly with the five isotopic substages (MIS 6a-b), however they are not completely divergent either: our zone 1 roughly correspond to MIS 6e-d, zone 2 to MIS 6c-b, and zones 3-4 to MIS 6a. As already pointed out for the last glacial period (e.g. Combourieu-Nebout et al., 2002, 2009; Masson-Delmotte et al, 2005; Genty et al., 2005), the vegetation and climate record of the Alboran Sea is influenced by both long-term (i.e. orbital) variability as also reflected in the reference isotopic subtages (MIS 5-1), and short term (i.e. millennial-scale) variability. Therefore, we believe it is still useful to discuss our results for MIS 6 in the frame of the reference oxygen isotopic nomenclature for clarity and to point out their differences and similarities.

-Fig. 5 legend: it is a black star (not red)

Done

-Lines 380-381. This sentence is too vague...the pollen results do not really agree with the MIS6 glacial substages (a-e) and/or D-O dynamics that are only defined for the last glaciation...maybe it would be better to say "D-O-like dynamics" and I would remove the glacial substages.

The pollen zones do partially agree with the glacial substages, as previously said and explained in the discussion. Differences in the temporal resolution and chronological control for the period might also affect the correlation between pollen/climate record and the isotopic substages. We think it is still useful to keep the reference isotopic framework for comparison with our record. Finally, the text already mentioned “D-O-like dynamics”, as indeed there is no reference chronostratigraphic framework for D-O events during MIS 6 yet.

-Lines 382-391: As these three phases don't coincide with the previously defined substages, I would remove those from the text and add ages when those phases occur in your record

As already mentioned, the three phases do correspond roughly to MIS 6 e-d, MIS 6 c-b, and MIS 6 a and we think it is useful to keep the isotopic reference framework.

However, we take in consideration your comment and propose the following changes: 1) adding the ODP 976 pollen zones to the figures for comparison with the isotopic subdivision, and 2) indicating the approximative dates of the pollen zones at the beginning of the discussion.

-Line 402-403. Please give the ages for the beginning and end of the termination II in your record and describe how you identified that termination in the ODP 976 pollen record

The ODP 976 marine record is tied to Dongge cave chronology, as detailed in the chronology section of the methods (section 3.2). The timing for TII in our record, based on marine indicators, is therefore the same as the weak Asian monsoon event during HS11. We added a sentence to insist on that point.

That being said, the following sentences refer strictly to the vegetation response to TII in our record, which is different and a bit delayed compared to the marine indicators.  

-Line 407: W?

Done

-Line 413: Do you mean the abrupt drop of temperatures at the beginning of HS11?

Yes. We added that precision to the sentence.

-Line 416: I would rather call this section "Hydroclimate connection..."

Done

-In Figure 3. Pioneer vegetation is represented by brown color, as Ericaceae here. Please be consistent and use the same color for the different categories in all figures

Thank you for this helpful comment. Colours were adjusted for Ericaceae and pioneer vegetation in Fig. 3.

-Line 455: Could you please explain why deciduous forest is important in better noticing the MIS7-6 transition? 

In the Eastern Mediterranean sites, a higher contrast has been described between interglacial periods with very high percentages of temperate deciduous forest taxa and glacial periods with very reduced tree cover (Tzedakis, 1993; Tzedakis et al., 2006). The western Mediterranean region, at the contrary, was generally characterized by a high proportion of herbaceous taxa, even during interglacial periods, attenuating the vegetation contrasts during transitions to glacial periods.  This trend is particularly visible in our figure for the MIS 7-6 transition.

-Lines 477-486. Maybe representing site MD01-2444 in Figure 6 would be usefull, even though it is not a Mediterranean site "per se", it looks like ODP 976 share a lot of similarities with it

We completely agree with your important suggestion. Unfortunately, the complete pollen data from MD01-2444 site are not publicly available. However, we added the two public curves of temperate and Mediterranean pollen taxa to the figure (although they were already shown in Fig. 7).

-Lines 481-486: Could it be due to lower summer insolation generating lower evaporation in summer and favouring the growth of Ericaceae, which requires humidity throughout the year?

Yes, this explanation was particularly developed by Fletcher & Sanchez Goni (2008) and can be applied here. We added this reference to strengthen this interpretation.

-Line 498: I would just say Moroccan Mountains - Cedrus could also originate from the Atlas

Done

-Line 505: Change across for throughout

Done

-Line 507: Not just rapid, but enhanced development of forest in that area

Done

-Line 508: Please explain why altitude is important here

Thank you for this relevant suggestion. We modified and completed our discussion as follows:

“This pattern of enhanced and rapid variations in tree cover at Tenaghi Philippon was already described during the last climatic cycle and reflects the exacerbated vegetation dynamics locally, with episodes of rapid and enhanced colonization by tree vegetation (Koutsodendris et al., 2023; Tzedakis, 2005; Tzedakis et al., 2004). This has been mainly explained by the location of the site in a low altitudinal plain characterized by a more continental climate with lower winter precipitation: tree population at lower altitudinal location are closer to their ecological threshold in term of precipitations, and are likely to be very affected even by minimal changes in the amount of rainfall.”

-Line 523: Please be more specific of why do you think it is compatible with DO-like variabilty. Is it the duration of the events? the intensity?

Yes, at first look they look like D-O events based on the vegetation dynamics, timing and intensity. Following your comment we added that precision to the sentence. “Finally, all palynological sequences reveal high-frequency oscillations of temperate and semi-desert pollen, compatible at first look with DO-like variability based on their duration and intensity.”

Then in section 5.5 we discuss their differences with the last glacial.

-Line 527: What does "disentangle the character" mean? investigate?

Yes, we replaced this word by “investigate”.

-Line 529. What do you mean with consistent? similar? in what? time? intensity? be more specific

Thank you for this comment. We changed the sentence as follows: “The events of arboreal pollen increase observed in the ODP 976 record show percentages and timing comparable to those from the Portuguese margin core MD01-2444 (Margari et al., 2010, 2014; Tzedakis et al., 2018) (Fig. 7, m).”

-Line 532: Remove "the" and change it for "its more semiarid"

Done

-Line 434. Confirm this, as earlier you said Ericaceae was a "cold" indicator (see line 303) - be consistent

Thank you for this comment.

Ericaceae show an ambiguous pattern when looking at both long-term and high-frequency patterns. They are connected to D-O events through the Atlantic influence on moisture availability (e.g. Fletcher & Sanchez Goni, 2008), but they are also a major component of the vegetation at time of glacial maximum like the LGM (Combourieu-Nebout et al., 2009). However, to avoid confusion and to be consistent we removed their qualification as “cold” indicators earlier.

-Line 539. This affirmation is very vague. There are significant differences between the Cueva Gitana and ODP 976, for example maximum humidity seems to occur at 148 kyr, which is not replicated in your record 

This is true and we therefore bring clarification on this point.

The maximum humidity at Cueva Gitana ~150 ka is not replicated in our record, but at that time we find several moderate increases of temperate forest pollen, and the climate reconstructions show a progressive amelioration from then. The differences between the two records are likely due to the different representativeness of the climatic signal between a speleothem, which mainly depends on local hydroclimate conditions, and a marine core which records regional climatic conditions. Considering these premises, we think that the two records generally show consistent trends. The records are not completely similar when looking into details, but this is also the case for SSTs, and also depends on the different time resolution and calibration applied to the different records.

We slightly modified our sentence to address the correlation between pollen-based climate reconstructions, SST and speleothem records with more caution: “The ODP 976 pollen-inferred climate reconstructions show generally consistent patterns with the SSTs trends based on alkenones (Martrat et al., 2004, 2007), and the southern Iberian humidity recorded in the speleothem from Cueva Gitana (Hodge et al., 2008) (Fig. 7).”

-Fig. 7. The text of the legends of the different plots should be written in a bigger size. 

Also, the scale in the synthetic pollen figure from ODP 976 is missing 

In addition, the pollen data do not really agree with the substage subdivision done by Railsback fro MIS 6 - I would remove that subdivision.

Thank you, we made the relevant modifications on the figure.

We kept the isotopic substages as explained before, but we addressed your suggestion by also adding the ODP 976 pollen zones for comparison on the figure.

-Lines 566-572: This paragraph is repetitive, see the beginning of the discussion in lines 382-415. I would remove it or synthesize those two paragraphs in one. Also, check more text in this section for further repetition

We moved these few sentences at the beginning of the first discussion section, where we describe the three phases during MIS 6.

-Lines 573-583. Check for repetitions in the sapropel discussion with the previous section about the ORLs - this could be synthesized...maybe adding the ORL text in this section?

We agree with you that some parts may sound repetitive.

However, we consider it is important to separate in discussion 1) a first short introduction to the presence of ORLs in our western Mediterranean record (which are less known than Sapropels) and their comparison with vegetation and climate results in the same core, and 2) a wider interpretation of hydroclimatic conditions integrating our record with other regional and global references.

-Line 589. How do the isotopic and sea surface temperature records reflect precipitation? Please explain

In this study, the isotopic and SST records are used to reconstruct surface water isotopic composition, which is a proxy for past salinity and is directly dependant on precipitation.

We added that precision to the sentence: “Higher pluviometry is supported by foraminifera isotopic and SSTs signal throughout the Mediterranean Sea, which were used to reconstruct past salinity and freshwater budget regionally”.

-The size of figure 9 as it is shown in the pdf here is too small - one can barely read the text-numbers so it should be bigger.

Done

-Line 903: replace "consistent with" with similar to

Done

-Line 917: Change "double u for "W"

Done

RC2

Revision Charton et al. (2025)

The study by Charton et al. (2025) presents new high-resolution pollen data and quantitative reconstructions of temperature and precipitation, which have been used to relate it to previous archaeological interpretations concerning human populations during MIS 6–5. Thanks to the high-resolution pollen analysis carried out (200 samples), the authors have also been able to explore short and intense paleoclimatic periods, such as the HS11. Therefore, despite certain issues described below in the section “Major comments,” the study provides valuable data and interesting multidisciplinary interpretations, making it a noteworthy contribution to the scientific community, and deserves publication after major revisions.

Major comments:

One of the main issues concerns the chronology of the studied core, which relies on correlations with other records through tie-points. Independent chronological control in marine archives for ages above the radiocarbon dating limit has been a common challenge in paleoclimate studies. However, in this case, the correlation of the studied core with the marine record MD01-2444, which also lacks independent age control and chronology, and which in turn is aligned with the Greenland δD record (Dome C ice-core), is problematic. This situation may lead to paleoclimatic reconstructions being subject to circular reasoning. Since the chronological framework represents one of the weaknesses of this study, it would be necessary to present the age alignments more explicitly to the reader, for example, by showing the depth correlations from the onset of MIS 6 to the present between the studied record and MD01-2444, as well as the tie-points linking MD01-2444 with the Greenland core. By showing the depth correlations for the last 200 ka together with the absolute ages (displayed alongside the depth axis) of records that are independently dated (in this case, the Antarctic Dome C ice-core), the reader can understand that the tie-points used here are potentially robust and that these alignments correspond to the same climatic variations of the penultimate glacial period. Similarly, no correlation graph is presented between the ODP 976 core and the Chinese speleothem records from Dongge Cave.

Thank you very much for this relevant comment on which we mostly agree. We are of course aware of the limitations of the tuning approach used for age calibration of the ODP 976 record, which can lead to circular interpretation of the paleoclimate signal if not taken carefully. However, in absence of any direct chronometric dates, the indirect paleoclimatic tuning is the best approach generally used for chronological calibration of marine cores, and we do not think it is “problematic”, if well-presented and justified. We therefore acknowledge the further need for justification and details on the chronological tuning approach.

We are unable to provide the correlation between ODP 976 and MD01-2444 records from MIS 6 to the present, as the pollen data from core MD01-2444 are not publicly available, and studies are still ongoing. We can therefore only provide the correlation between temperate pollen from the two cores between 195 and 125 ka as already shown in Fig. 2. Besides, the tie-points of core MD01-2444 benthic isotopic record to Epica Dome C are taken directly from Shin et al. (2020), based on the AICC2012 chronology (Bazin et al., 2013). We added a new supplementary table including the tie-points between core MD01-2444 and EDC (11 tie-points, between 135 and 195 ka, taken from Shin et al., 2020), and Corchia cave (7 tie points between 126-139 ka, taken from Tzedakis et al, 2018).

Regarding the correlation between ODP 976 SSTs and speleothem records, the alignment was already presented in Jiménez Amat & Zahn (2015). We added a supplementary figure to show the graphical correlation between the three records with the tie-points taken from the original publication.

We hope that these supplementary files, as well as more explicit reference to the original publications justifications and limitations (see response to Reviewer 1), can bring clarification and transparency to our approach.

Regarding the quantitative reconstructions, the authors should provide a clearer specification of the modern pollen training set used for the reconstructions. It is indicated that the dataset of Peyron et al. (2013, 2017) and updated by Dugerdil et al. (2021) and Robles et al. (2023) was employed. However, it is essential to include the total number of harmonized taxa used for reconstructions and should also mention any taxa that have been excluded, for example, aquatics. It would also be helpful to show a map displaying the location of all the modern samples used. They should also specify the area, including the latitude and longitude of this training set. It would also be useful to see the maximum bias for each method in Table 3. To better understand which taxa are responsible for the changes observed in the reconstructions, I also suggest including a figure showing the tolerance spectra of the main pollen taxa for each of the climatic parameters used (MAAT, MTCO, TCON, MAP, WINTERRR, PCON).

Thank you for these very helpful suggestions. All the required details have been added in the text, and we included a map of the modern pollen dataset in the Supplements (Fig. S2). We also added an additional figure in Supplements showing the tolerance spectra of the main pollen taxa to the six climate parameters reconstructed (Fig. S3). A small paragraph has been added on this matter:

 “The climatic tolerance spectra of the ten most abundant pollen taxa in the ODP 976 record have been reconstructed based on the modern dataset (Supplement, Fig. S3). They show shat steppe and semi-desert taxa display the highest tolerance to low winter temperature and precipitation, while Mediterranean taxa (Olea and Quercus ilex-type) are the most tolerant taxa to high annual and summer temperature, and Cedrus and Ericaceae to higher annual and seasonal precipitation.”

Finally, the best R2 and RMSE values for each method has been shown in bold in Table 3.

At the end of section 5.1, a delay of around 1000 years is mentioned with respect to the marine SST of ODP 976 (Jiménez-Amat and Zahn, 2015; Martrat et al., 2014). Considering that this is the same record, why does this delay occur? Is this due to a delay in the continental response compared to that recorded in the sea? Is the age model of Jiménez-Amat and Zahn (2015) and Martrat et al. (2014) based on the same tie-points as this study, and therefore the age chronology is the same? If not, then referring to a delay of only 1,000 years when dealing with interpretations for MIS 6, and considering that the chronological control is not independent and relies on correlations between warm events, appears at the very least, risky and potentially overinterpreted.

Our age model uses the same tie-points than Jiménez Amat & Zahn (2015). Regarding the ~1000 years delay, it corresponds to a delay in the vegetation response to cold water entrance. When looking at the ODP 976 SST record, cold temperatures start at ~134.5 ka, while steppe and semi-desert pollen peak only at ~133.3 ka (start of pollen zone 4).

We added a sentence to clarify this point: “This delay in marine and terrestrial proxies may reflect the vegetation response to the first cold pulse of HS11.”

In section 5.4, the authors analyze the HS11 signal in OPD 976 and other records. Although they mention the difference in intensities recorded between the eastern and western Mediterranean, they do not delve into the climatic mechanisms that could have led to this difference between the two areas.

Thank you for this relevant comment. We discussed further this point as follows: “This observation is compatible with previous observations that Heinrich stadials during the last glacial had a minor impact on the eastern Mediterranean vegetation compared to the western Mediterranean, likely due to the already limited presence of tree vegetation in the eastern records during glacials (Tzedakis, 2005). A similar interpretation can be proposed for the differential response of eastern and western Mediterranean vegetation to HS11, supporting the major sensitivity of the southwestern Mediterranean vegetation to North Atlantic cold events.”

Minor comments:

In Methods, I suggest including the average resolution of pollen samples in age. Taking into account the beginning (195.72 ka BP) and end of the record (127.47 ka BP), and the 200 pollen samples analyzed, the average resolution should be approx. 341 years/sample. Please verify this.

Yes, this indication was already mentioned at line 205 in the age model methods.

Mention the meaning of “mcd” when it first appears in Table 1 or in Line 215, not in Figure 3.

Corrected.

Explain why a radius of 400 km is used to calculate the average value of climate parameters. Pollen influence is reduced beyond a radius of 175 km (Rojo et al., 2016). However, other studies suggest that pollen can be transported up to distances of 200-300 km (Fernández-Rodríguez et al., 2014), and even over distances greater than 500 km (Bayr et al., 2023; Bogawski et al., 2019). The authors could use some of these studies to explain the radius used to obtain the recent average values.

Thank you very much for this suggestion. We modified the paragraph as follows: “Pollen dispersal is reduced beyond a radius of 175 km (Rojo et al., 2016). However, other studies suggest that pollen can be transported up to distances of 200-300 km (Fernández-Rodríguez et al., 2014) and even over distances greater than 500 km (Bayr et al., 2023; Damialis et al., 2017). Sediments from marine cores such as ODP 976 can therefore include close and long-distance pollen. To account for these observations, an averaged value of the climate parameters on a 400 km radius around the ODP 976 site was extracted.”

Lines 263-266: Authors should mention the total number of harmonized taxa that compose the training set.

Changed to “A total of 103 harmonized pollen taxa are included in the dataset, excluding Pinus and aquatic taxa”

Line 300: “Jeanne Rampal, personal communication”. Provide the age of the communication.

Done (2023).

Lines 872 and 917: Use HS11 instead of “Heinrich Stadial 11”

Done.

Figure 6: Explain why Pinus was included as pioneer vegetation in Ioannina and why it was not included in other records.

Pinus was included in pioneer vegetation at Ioannina, as it is the only record where Pinus is not over-represented. This precision was added in Fig. 6 legend.

To facilitate reading between the text and the figures, I suggest including the letters of the curves when referring to a record in a figure, especially when referring to records in Figure 7.

 Done.

New references cited:

Rojo, J. et al. Modeling olive pollen intensity in the Mediterranean region through analysis of emission sources. Science of The Total Environment 551-552, 73-82 (2016).

Fernández-Rodríguez, S. et al. Identification of potential sources of airborne Olea pollen in the Southwest Iberian Peninsula. International Journal of Biometeorology 58, 337-348 (2014).

Bayr, D. et al. Pollen long-distance transport associated with symptoms in pollen allergics on the German Alps: An old story with a new ending? Science of The Total Environment 881, 163310 (2023).

Bogawski, P., Borycka, K., Grewling, Ł. Kasprzyk, I. Detecting distant sources of airborne pollen for Poland: Integrating back-trajectory and dispersion modelling with a satellite-based phenology. Science of The Total Environment 689, 109-125 (2019).

 RC3

As an archaeologist specializing in Pleistocene hunter-gatherer adaptations rather than a palaeoclimatologist, I want to be transparent that my evaluation focuses primarily on the archaeological interpretations and the human-environment dynamics discussed in this paper. With that acknowledged, this study provides a valuable paleoenvironmental framework that is sorely needed for understanding human occupation patterns during MIS 6 in the Western Mediterranean, a period that remains critically understudied compared to the Last Glacial.

The paper deserves publication for several key reasons from an archaeological perspective:

Major strengths:

1. Filling a critical gap in human-environment research: The archaeological record for MIS 6 is notoriously sparse and poorly dated. This high-resolution paleoenvironmental sequence from the Alboran Sea provides the chronological and environmental context that archaeologists desperately need to understand the Lower to Middle Palaeolithic transition and Neanderthal population dynamics during this period. The 200-sample resolution (~341 years/sample) allows correlation with human occupation phases at much more detailed level.
2. The climate refugia hypothesis: The paper's demonstration that the SW Mediterranean maintained relatively stable (though harsh) conditions during MIS 6, combined with the archaeological synthesis showing continuous human presence in Southern France and Iberia, strengthens the long-standing refugia model for this region. This has important implications for understanding Neanderthal metapopulation dynamics and the persistence of "source" populations.
3. HS11 as a potential demographic bottleneck: The identification of Heinrich Stadial 11 (~133-129 ka BP) as a particularly severe event in the Western Mediterranean is archaeologically significant. The observation that many MIS 6 sites show chronological boundaries compatible with TII onset (~136 ka BP) is compelling and suggests this event may have been a catalyst for population contraction and technological reorganization. This interpretation aligns well with genetic evidence for Neanderthal demographic stability only emerging after MIS 5e.
4. The archaeological synthesis (Section 5.6): This section provides a useful compilation of dated MIS 6 sites across SW Europe, distinguishing between cave and open-air contexts, and discussing the technological mosaic of Acheulean and Early Middle Palaeolithic assemblages. The regional comparison (Italy vs. Iberia vs. Southern France) offers insights into differential human responses to glacial conditions.

Suggestions for improvement:

1. Expand discussion of behavioral adaptations: While the paper mentions changes in land use, mobility patterns, and subsistence strategies during MIS 6 (citing Diez-Martín, Sánchez-Yustos, and Rios-Garaizar), these could be developed further. How do the three environmental phases identified in ODP 976 correlate with observable changes in lithic technology, site function, or faunal exploitation patterns? For instance, does the shift from Early MIS 6 (humid, variable) to Middle MIS 6 (full glacial, stable) correspond to changes in raw material procurement ranges or prey selection documented at sites like Bolomor or Lazaret?

Thank you very much for your comment. This is a very interesting question, but very hard to answer based on the available archaeological record. Few sites dated to MIS 6 provide sufficient information and resolution to distinguish different phases during MIS 6. Bolomor and Lazaret caves are probably the sites with the highest archaeological resolution and available information to identify potential different cultural phases during MIS 6. We added two paragraphs specifically focusing on these two sites.

In Bolomor Cave, the literature does not mention any change in lithic production during MIS 6: according to Fernández Peris (2008), archaeological layers XII to VII (Phase III-MIS 6) are all dominated by limestone flakes with few retouches, few recycling, and the presence non-Acheulean macro-lithic elements. These layers are characterized by expeditive flaking (including Levallois débitage) relying on local raw-material, pointing toward a high degree of mobility and search for immediate effectiveness. It is hard to distinguish different tendencies during this phase. The most visible change in the archaeological sequence occurs during MIS 5 (layer VI), which shows an intensification of lithic production dominated by flint, the production of more specialized tools including microlithic elements and associated to more intense and stable occupation in the cave (Fernandez Peris, 2008). Therefore, a true behavioural change in the technological and economical exploitation of raw materials is identified at the beginning of MIS 5. Faunal remains show a large and constant diversity, including abundant micro supporting both short-term and long-term not-specialized occupation, with no clear change in the site’s function across the sequence (Blasco et al., 2013).

Lazaret cave shows a very distinct scheme: the LMPT is well documented in the archaeological sequence (Unit CII and CIII), with the progressive replacement of large bifacial tools production by more standardized and smaller flakes (Cauche, 2012). Levallois débitage is already present and well-mastered in the lower MIS 6 levels, although rare, and becomes dominant in the upper levels (early MIS 5). Therefore, a subdivision of unit CII can be made with a lower interval rich in handaxes, and an upper layer characterized as “final Acheulean” with rare handaxes and more flakes. Faunal assemblages is very constant throughout the 29 layers of Lazaret cave documenting human presence during MIS 6, with the large dominance of red deers and rare presence of cold species (Rangifer tarandus, Coelodonta antiquitatis). The climatic oscillations of MIS 6 do not seem to have influenced different hunting strategies or prey selection by human populations, as large game hunting of red deer prevailed (Valensi et al., 2013).

Therefore, Lazaret and Bolomor caves are examples of different strategies of site exploitation and technological evolution during MIS 6: Lazaret Cave represents a specialized red-deer hunting camp evidencing a progressive change from Lower to Middle Palaeolithic tools, while Bolomor Cave can be characterized as a short-term camp with more generalized hunting and stable expeditive Middle Palaeolithic industry. Both sites provide evidence for a change in lithic assemblages occurring at the end of MIS 6/ beginning of MIS 5: the disappearance of handaxes and generalization of Levallois flakes in Lazaret, and the intensification and standardization of flint flaxes in Bolomor.

1. Consider Neanderthal niche modeling: The brief mention of Yaworsky et al. (2024) showing reduced niche space at ~145 ka BP is intriguing but underexplored. How do the climate reconstructions presented here compare with modeled Neanderthal climatic tolerances? This could strengthen the argument about population contraction during full glacial conditions.

We propose to develop a bit further the reference to the study by Yaworsky et al (2024), as follows:

A niche modelling approach based on 41 sites of Western Eurasia since 145 ka BP has shown that the projected potential niche space for Neanderthals at the end of MIS 6 (~145ka BP) was very reduced and concentrated in Western Europe (Yaworsky et al., 2024). This coincides with the end of pollen zone 2 in the ODP 976 record, the most cold and arid phase of the penultimate Glacial before HS11. Then, the authors reconstruct a progressive expansion of Neanderthal potential niche space between 145 and 130 ka, compatible with the climatic warming and moistening during pollen zone 3 in the ODP 976 record (Yaworsky et al., 2024). The temporal resolution of the model (1000 years) does not allow to detect the impact of HS11 on the niche projection, and only a small slowdown and decline of the projected niche is visible at ~130 ka BP, before the MIS 5e optimum (Yaworsky et al., 2024, Fig. 5).

1. The Lower to Middle Palaeolithic transition: The paper suggests that MIS 6 glaciation "could have played a role in the final abandonment of Acheulean industries." This is an important claim that deserves more nuanced treatment. What specific environmental pressures might have favoured Levallois technology over bifacial production? Were these pressures most acute during the cold-dry middle phase or during the rapid oscillations of early MIS 6? The environmental data presented here could potentially contribute to this long-standing debate.

This is a very interesting comment, although complex to answer. We propose to contribute further to this debate as follows:

“It is hard to claim that specific environmental pressures favoured Levallois technology over bifacial production, as these lithic technologies seem to have co-existed in Western Europe since MIS 12-11 over several glacial/interglacial cycles (Moncel et al. 2021; Baena et al., 2017), including extremely cold stages (like MIS 12 and 10). This “mosaic” pattern for the lower to middle palaeolithic transition, although at least partly imputable to the large dating uncertainties, points toward more complex processes leading to the generalization of Middle Palaeolithic industries from MIS 5.

Interestingly, the end of the Lower to Middle Palaeolithic transition is also associated with a shift in the morphology of human remains, from “Early Neanderthals” (MIS 7-5) to “Classical Neanderthals” (MIS 5-3) (Di Vincenzo & Manzi, 2023). Sites like La Chaise (Abri Suard), Lazaret and Altamura provide fossil evidence for these “Early Neanderthals” which share characteristics with earlier Middle Pleistocene populations, and with later Neanderthals (de Lumley et al., 2018; Couture-Veschambre et al., 2021). Genetic data also support an important population shift in western Europe sometimes around the transition from MIS 6 to MIS 5 (Peyrégne et al., 2019). Therefore, an important population reorganization seems to have occurred at the time of the final Acheulean industries, leading to the onset of the so-called “Classical neanderthal world” in western Eurasia, with generalized Middle Palaeolithic industries and established Neanderthal morphological features. The role of environmental changes occurring during MIS 6 in this population reorganization remains poorly understood.”

1. Site-level correlations: While the archaeological synthesis is valuable, the temporal resolution of most archaeological sites remains too coarse for direct correlation with specific interstadials or stadials identified in ODP 976. The paper should acknowledge this limitation more explicitly and perhaps identify which sites have the chronological precision to test human-environment correlations at sub-orbital scales.

We absolutely agree with this comment. The first paragraph of our discussion on archaeology starts with acknowledging this limitation of the chronological and archaeological data. We further strengthen this observation, and explicitly identify Bolomor and Lazaret caves as the most informative sites for further discussion:

“Even when absolute dates are available, their large uncertainty range and the poor resolution of the archaeological record represent a major limitation and makes it difficult to correlate the human occupation phases with a specific substage of MIS 6.”

 “However, identifying cultural phases in the archaeological sequences linked with specific climatic episodes is generally hindered by the poor resolution of the archaeological record and chronological data. Among the sites identified in this synthesis, Lazaret and Bolomor caves probably present the most informative and well-dated sequences with several archaeological layers dated to MIS 6.”

1. Clarify the refugia concept: The paper uses "climate refugia" somewhat interchangeably for both vegetation and human populations. It would be worth discussing whether areas that served as refugia for temperate vegetation necessarily corresponded to optimal habitats for Neanderthals, who were evidently capable of exploiting a broader range of environments than many plant communities.

We agree on this statement, and bring clarification in the introduction:

“Neanderthal presence in very distinct ecotones in Eurasia proves it could adapt to a very wide range of environments. However, recent niche modelling approaches together with palaeoecological data from archaeological sites strengthened the view that warm forested landscapes like the MIS 5e environments represented the most suitable habitats for Neanderthals, where they could persist during colder periods (Carrión et al., 2026; Ochando et al., 2019; Stewart et al., 2019; Trájer, 2023). This conception leads to the overlap of the notions of refugium for vegetation and human populations, despite the greatest adaptability and niche extension of humans.”

1. HS11 and human response: The claim that HS11 "did not lead to complete extinction of hominin groups but might have induced deep demographical and technological reorganization" is compelling but would benefit from more specific archaeological evidence. Are there observable differences in assemblage composition, site density, or raw material use between pre-HS11 and post-HS11 contexts in the region?

Yes, as discussed with the examples of Lazaret and Bolomor caves. The observed changes in the lithic assemblage’s composition and occupation density has traditionally been linked with MIS 6 / 5 transition, with no particular reference to HS11 event, because it was poorly studied. After HS11, at the onset of MIS 5, we find more sites evidencing more intense occupation, generalized flake production, and absence of handaxes. We hope that the precedent changes sufficiently address this question. A more detailed comparison of pre-HS11 and post-HS11 human presence would be outside the scope of this paper, and should be addressed in a future study focused on this specific period.

1. The comparison of MIS 6 with MIS 4-2 (Section 5.5) from the same core is methodologically valuable. However, the archaeological implications of the "subdued" millennial variability during MIS 6 compared to the Last Glacial could be discussed more explicitly. Did reduced climate oscillation frequency translate to different patterns of population mobility or technological change?

This is again a very interesting question, which is hard to answer because of the very different quality of preservation of the archaeological record for MIS 4-2 compared to MIS 6. A detailed analysis of the archaeological record of MIS 4-2 for comparison with MIS 6 is outside of the scope of this paper and would need another appropriate study.

However, to address this comment, we added a sentence on this matter at the end of the paragraph: “In that sense, the subdued environmental instability during MIS 6 evidenced in the OD P976 record compared to the last glacial period (Section 5.5 and Fig. 9) could also have implications for human populations, with less fragmented (although harsh) habitats and more stable (although reduced) population during MIS 6. This hypothesis remains however hard to test based on the very different nature and quality of preservation of the archaeological record during MIS 6 compared to MIS 4-2 (e.g. Charton et al., 2025).”

Conclusion:



This paper makes a significant contribution by providing the high-resolution paleoenvironmental framework necessary to understand human-environment dynamics during a critical but understudied period. The identification of three distinct environmental phases during MIS 6, the characterization of HS11 as a severe event in the Western Mediterranean, and the archaeological synthesis of human occupation patterns all advance our understanding of Neanderthal adaptations during the penultimate glaciation. I recommend publication after revisions that strengthen the archaeological interpretations and address the chronological limitations of site-level correlations.