@article {holt_tropical_2023,
	title = {A Tropical Cocktail of Organic Matter Sources: Variability in Supraglacial and Glacier Outflow Dissolved Organic Matter Composition and Age Across the Ecuadorian Andes},
	journal = {Journal of Geophysical Research: Biogeosciences},
	volume = {128},
	number = {5},
	year = {2023},
	note = {_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1029/2022JG007188},
	month = {05/2023},
	pages = {e2022JG007188},
	abstract = {The biogeochemistry of rapidly retreating Andean glaciers is poorly understood, and Ecuadorian glacier dissolved organic matter (DOM) composition is unknown. This study examined molecular composition and carbon isotopes of DOM from supraglacial and outflow streams (n = 5 and 14, respectively) across five ice capped volcanoes in Ecuador. Compositional metrics were paired with streamwater isotope analyses (δ18O) to assess if outflow DOM composition was associated with regional precipitation gradients and thus an atmospheric origin of glacier DOM. Ecuadorian glacier outflows exported ancient, biolabile dissolved organic carbon (DOC), and DOM contained a high relative abundance (RA) of aliphatic and peptide-like compounds (>=27\%RA). Outflows were consistently more depleted in Δ14C-DOC (i.e., older) compared to supraglacial streams (mean -195.2 and -61.3{\textperthousand} respectively), perhaps due to integration of spatially heterogenous and variably aged DOM pools across the supraglacial environment, or incorporation of aged subglacial OM as runoff was routed to the outflow. Across Ecuador, Δ14C-DOC enrichment was associated with decreased aromaticity of DOM, due to increased contributions of organic matter (OM) from microbial processes or atmospheric deposition of recently fixed and subsequently degraded OM (e.g., biomass burning byproducts). There was a regional gradient between glacier outflow DOM composition and streamwater δ18O, suggesting covariation between regional precipitation gradients and the DOM exported from glacier outflows. Ultimately, this highlights that atmospheric deposition may exert a control on glacier outflow DOM composition, suggesting regional air circulation patterns and precipitation sources in part determine the origins and quality of OM exported from glacier environments.},
	keywords = {cryosphere, dissolved organic carbon, Dissolved organic matter, Ecuador, FT-ICR MS, glaciers, δ13C-DOC, Δ14C-DOC},
	issn = {2169-8961},
	doi = {10.1029/2022JG007188},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1029/2022JG007188},
	author = {Holt, Amy D. and Kellerman, Anne M. and Battin, Tom. I. and McKenna, Amy M. and Hood, Eran and Andino, Patricio and Crespo-P{\'e}rez, Ver{\'o}nica and Peter, Hannes and Sch{\"o}n, Martina and De Staercke, Vincent and Styllas, Michail and Tolosano, Matteo and Spencer, Robert G. M.}
}
@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 {2676,
	title = {Removal of Refractory Dissolved Organic Carbon in the Amundsen Sea, Antarctica},
	journal = {Scientific Reports},
	volume = {10},
	year = {2020},
	month = {Jan-12-2020},
	abstract = {The removal mechanism of refractory deep-ocean dissolved organic carbon (deep-DOC) is poorly understood. The Amundsen Sea Polynya (ASP) serves as a natural test basin for assessing the fate of deep-DOC when it is supplied with a large amount of fresh-DOC and exposed to strong solar radiation during the polynya opening in austral summer. We measured the radiocarbon content of DOC in the water column on the western Amundsen shelf. The radiocarbon content of DOC in the surface water of the ASP reflected higher primary production than in the region covered by sea ice. The radiocarbon measurements of DOC, taken two years apart in the ASP, were different, suggesting rapid cycling of DOC. The increase in DOC concentration was less than expected from the observed increase in radiocarbon content from those at the greatest depths. Based on a radiocarbon mass balance, we show that deep-DOC is consumed along with fresh-DOC in the ASP. Our observations imply that water circulation through the surface layer, where fresh-DOC is produced, may play an important role in global DOC cycling.},
	keywords = {CIRCUMPOLAR DEEP-WATER, cycle, DOC, glaciers, INFLOW, MATTER, pacific, phytoplankton, poc, radiocarbon},
	doi = {10.1038/s41598-020-57870-6},
	url = {http://www.nature.com/articles/s41598-020-57870-6http://www.nature.com/articles/s41598-020-57870-6.pdfhttp://www.nature.com/articles/s41598-020-57870-6.pdfhttp://www.nature.com/articles/s41598-020-57870-6},
	author = {Fang, Ling and Lee, SangHoon and Lee, Shin-Ah and Hahm, Doshik and Kim, Guebuem and Druffel, Ellen R. M. and Hwang, Jeomshik}
}
@article {Cui2016238,
	title = {Biospheric and petrogenic organic carbon flux along southeast Alaska},
	journal = {Earth and Planetary Science Letters},
	volume = {452},
	year = {2016},
	pages = {238 - 246},
	abstract = {Abstract Holocene fjords store ca. 11{\textendash}12\% of the total organic carbon (OC) buried in marine sediments with fjords along southeast (SE) Alaska possibly storing half of this \{OC\} (Smith et al., 2015). However, the respective burial of biospheric (OCbio) and petrogenic \{OC\} (OCpetro) remains poorly constrained, particularly across glaciated versus non-glaciated systems. Here, we use surface sediment samples to quantify the sources and burial of sedimentary \{OC\} along \{SE\} Alaska fjord-coastal systems, and conduct a latitudinal comparison across a suite of fjords and river-coastal systems with distinctive \{OC\} sources. Our results for \{SE\} Alaska show that surface sediments in northern fjords (north of Icy Strait) with headwater glaciers are dominated by OCpetro, in contrast to marine and terrestrially-derived fresh \{OC\} in non-glaciated southern fjords. Along the continental shelf of the Gulf of Alaska, terrestrial \{OC\} is exported from rivers. Using end-member mixing models, we determine that glaciated fjords have significantly higher burial rates of \{OCpetro\} ( \~{} 1.1 {\texttimes} 10 3 ~ g \{OC\} ~ m - 2 yr - 1 ) than non-glaciated fjords and other coastal systems, making \{SE\} Alaska potentially the largest sink of \{OCpetro\} in North America. In contrast, non-glaciated fjords in \{SE\} Alaska are effective in burying marine \{OC\} (OCbio-mari) (13{\textendash}82 g  \{OC\} ~ m - 2 yr - 1 ). Globally, \{OC\} in fjord sediments are comprised of a mixture of \{OCpetro\} and fresh OCbio, in contrast to the pre-aged \{OC\} from floodplain river-coastal systems. We find that there may be a general latitudinal trend in the role of fjords in processing OC, where high-latitude temperate glacial fjords (e.g., Yakutat Bay, \{SE\} Alaska) rebury \{OCpetro\} and non-glacial mid-latitude fjords (e.g., Doubtful Sound, Fiordland) sequester \{CO2\} from phytoplankton and/or temperate forests. Overall, we propose that fjords are effective in sequestering \{OCbio\} and re-burying OCpetro. Based on our study, we hypothesize that climate change will have a semi-predictable impact on fjords{\textquoteright} \{OC\} cycling in the near future.},
	keywords = {glaciers},
	issn = {0012-821X},
	doi = {http://doi.org/10.1016/j.epsl.2016.08.002},
	url = {http://www.sciencedirect.com/science/article/pii/S0012821X16304162},
	author = {Xingqian Cui and Thomas S. Bianchi and John M. Jaeger and Richard W. Smith}
}
