@article {puleo_younger_2022,
	title = {Younger Dryas and early Holocene climate in south Greenland inferred from oxygen isotopes of chironomids, aquatic Moss, and Moss cellulose},
	journal = {Quaternary Science Reviews},
	volume = {296},
	year = {2022},
	month = {11/2022},
	pages = {107810},
	abstract = {Ice core records have long indicated that the Younger Dryas began and ended with large, abrupt climate shifts over Greenland. Key climatic features remain unknown, including the magnitude of warming during the Younger Dryas-Holocene transition along with the seasonality and spatial variability of Younger Dryas climate changes across Greenland. Here, we use geochemical and paleoecological proxies from lake sediments at Lake N14 in south Greenland to address these outstanding questions. Radiocarbon dating and diatom assemblages confirm early deglaciation and isolation of Lake N14 before \~{}13,600~cal~yr BP, consistent with previous work. Oxygen isotope ratios (δ18O) of chironomid head capsules, bulk aquatic moss, and aquatic moss-derived cellulose are used to reconstruct oxygen isotopes of past lake water and annual precipitation. Oxygen isotope proxies indicate annual precipitation δ18O values increased by 5.9{\textendash}7.7{\textperthousand} at the end of the Younger Dryas. Following the Younger Dryas, moss and cellulose δ18O values show a clear decline in precipitation δ18O values of 2{\textendash}3{\textperthousand} from \~{}11,540{\textendash}11,340~cal~yr BP that may correspond with the Preboreal Oscillation. Reconstructed precipitation δ18O values then gradually increased from 11,300{\textendash}10,100~cal~yr BP. All three aquatic organic materials register similar shifts in precipitation δ18O values over time, and they closely parallel the δ18O shifts observed in ice cores. This evidence strongly supports the utility of these methods for reconstructing lake water δ18O, and furthermore precipitation δ18O values where lake water reflects precipitation. The relatively large shift in isotopic composition of precipitation at Lake N14 suggests that shifts in temperature, precipitation seasonality, and/or moisture sources at the end of the Younger Dryas were even larger in south Greenland than they were in central Greenland, most likely because of the proximity to major changes in North Atlantic Ocean circulation. The annual air temperature change estimated at Lake N14 at the end of the Younger Dryas is also very large (\~{}18~{\textpm}~7~{\textdegree}C) compared to the summer warming previously inferred from chironomid species assemblages there (\~{}6~{\textdegree}C). This indicates that the strongest warming at the end of the Younger Dryas occurred in the winter season, consistent with past observations of intensified Younger Dryas seasonality at Lake N14 and elsewhere in Greenland.},
	keywords = {Chironomids, Deglaciation, diatoms, Greenland, Holocene, Micropaleontology, paleoclimatology, paleolimnology, Stable isotopes, Younger Dryas},
	issn = {0277-3791},
	doi = {10.1016/j.quascirev.2022.107810},
	url = {https://www.sciencedirect.com/science/article/pii/S0277379122004413},
	author = {Puleo, Peter J. K. and Masterson, Andrew L. and Medeiros, Andrew S. and Schellinger, Grace and Steigleder, Regan and Woodroffe, Sarah and Osburn, Magdalena R. and Axford, Yarrow}
}
@article {2688,
	title = {Holocene temperature and landscape history of southwest Greenland inferred from isotope and geochemical lake sediment proxies},
	journal = {Quaternary Science Reviews},
	volume = {239},
	year = {2020},
	month = {Jan-07-2020},
	pages = {106358},
	abstract = {Terrestrial temperature reconstructions from the ice-free margins of Greenland are critical for constraining the sensitivity of the Greenland ice sheet to past climate change. Numerous investigations have clarified the glacial history of southwest Greenland in recent decades; however, very few local quantitative temperature reconstructions exist as context for changes in the cryosphere. We examine sedimentary records from two lakes south of Nuuk, Greenland (informally named lakes T1 and T2), and investigate millennial scale Holocene climate change using a multi-proxy approach. Changes in X-Ray fluorescence spectroscopy (XRF), δ15N, δ13C and biogenic silica concentrations of bulk lake sediments mark the transition from a marine environment to isolated lakes as relative sea level fell in the early Holocene. δ18O values of subfossil insects (chironomids) from lakes T1 and T2 decreased by 2{\textendash}3{\textperthousand} from c. 8.8 ka BP (minimum limiting age for the onset of lacustrine sediment deposition in lake T2; ka BP = thousands of years before 1950) to 1 ka BP. Existing isotope-independent temperature reconstructions from the west coast of Greenland suggest that these changes in δ18O values accompanied gradual cooling of 2{\textendash}4 {\textdegree}C, concomitant with decreasing summer insolation. There is widespread regional evidence that this cooling resulted in progressive regrowth of local glaciers and of the ice sheet. The regional consensus on the magnitude of this temperature change indicates that the local, modern modeled temperature - precipitation δ18O relationship cannot be used to quantify millennial-scale temperature changes at these sites through the Holocene. This reinforces that studies utilizing δ18O-based proxies to infer temperature change should carefully assess local isotope-temperature relationships over space and time.},
	keywords = {Chironomids, glaciers, Greenland, Isolation basins, lake sediments, oxygen isotopes, Paleotemperatures, Stable isotopes},
	issn = {02773791},
	doi = {10.1016/j.quascirev.2020.106358},
	url = {https://www.sciencedirect.com/science/article/pii/S0277379120303206},
	author = {Lasher, G. Everett and Axford, Yarrow and Masterson, Andrew L. and Berman, Karalyn and Larocca, Laura J.}
}
@article {2601,
	title = {Holocene temperatures and isotopes of precipitation in Northwest Greenland recorded in lacustrine organic materials},
	journal = {Quaternary Science Reviews},
	volume = {170},
	year = {2017},
	month = {Jan-08-2017},
	pages = {45 - 55},
	abstract = {Reconstructions of Holocene lake water isotopic composition based upon subfossil aquatic organic material offer new insights into Arctic
climate. We present quantitative estimates of warmth during the Holocene Thermal Maximum in northwest Greenland, inferred from oxygen isotopes of chironomid head capsules and aquatic moss preserved in lake sediments. delta O-18 values of chironomids from surface sediments of multiple Greenland lakes indicate that these subfossil remains record the delta O-18 values of the lake water in which they grow. Our lake water delta O-18 reconstruction is supported by downcore agreement with delta O-18 values in aquatic moss and chironomid remains. delta O-18 of both organic materials from Secret Lake decrease after 4 ka (ka = thousands of years ago) by 3 parts per thousand into the Neoglacial. We argue that lake water at Secret Lake primarily reflects precipitation delta O-18 values, which is strongly correlated with air temperature in NW Greenland, and that this signal is biased towards summer and early autumn conditions. Other factors may have influenced Secret Lake delta O-18 values through the Holocene, including evaporation of lake water and changing seasonality and source of precipitation. The maximum early Holocene summer and early autumn-biased temperature anomaly at Secret Lake is 2.5-4 degrees C warmer than present from 7.7 (the beginning of our record) to similar to 6 ka. The maximum late Holocene cold anomaly (which includes the Little Ice Age) is 1.5-3 degrees C colder than present. These ranges of possible temperature anomalies reflect uncertainty in the delta O-18 temperature relationship for precipitation at the study site through the Holocene. (C) 2017 Elsevier Ltd. All rights reserved.},
	keywords = {Chironomids, Greenland, Holocene, paleoclimatology, paleolimnology, Stable isotopes},
	issn = {02773791},
	doi = {10.1016/j.quascirev.2017.06.016},
	url = {http://linkinghub.elsevier.com/retrieve/pii/S0277379116305650http://api.elsevier.com/content/article/PII:S0277379116305650?httpAccept=text/xmlhttp://api.elsevier.com/content/article/PII:S0277379116305650?httpAccept=text/plain},
	author = {Lasher, G. Everett and Axford, Yarrow and McFarlin, Jamie M. and Kelly, Meredith A. and Osterberg, Erich C. and Berkelhammer, Max B.}
}
