@article {4586,
	title = {Diatoms in hyporheic sediments trace organic matter retention and processing in the McMurdo Dry Valleys, Antarctica},
	journal = {Journal of Geophysical Research: Biogeosciences},
	volume = {126},
	year = {2021},
	month = {02/2021},
	pages = {e2020JG006097},
	abstract = {<p>In low-nutrient streams in cold and arid ecosystems, the spiraling of autochthonous particulate organic matter (POM) may provide important nutrient subsidies downstream. Because of its lability and the spatial heterogeneity of processing in hyporheic sediments, the downstream transport and fate of autochthonous POM can be difficult to trace. In Antarctic McMurdo Dry Valley (MDV) streams, any POM retained in the hyporheic zone is expected to be derived from surface microbial mats that contain diatoms with long-lasting silica frustules. We tested whether diatom frustules can be used to trace the retention of autochthonous POM in the hyporheic zone and whether certain geomorphic locations promote this process. The accumulation of diatom frustules in hyporheic sediments, measured as biogenic silica, was correlated with loss-on-ignition organic matter and sorbed ammonium, suggesting that diatoms can be used to identify locations where POM has been retained and processed over long timescales, regardless of whether the POM remains intact. In addition, by modeling the upstream sources of hyporheic diatom assemblages, we found that POM was predominantly derived from N-fixing microbial mats of the genus Nostoc. In terms of spatial variability, we conclude that the hyporheic sediments adjacent to the stream channel that are regularly inundated by daily flood pulses are where the most POM has been retained over long timescales. Autochthonous POM is retained in hyporheic zones of low-nutrient streams beyond the MDVs, and we suggest that biogenic silica and diatom composition can be used to identify locations where this transfer is most prevalent.</p>},
	keywords = {LTER-MCM, benthic processes, biogenic silica, biogeochemical cycles processes and modeling, carbon cycling, diatoms, groundwater/surface water interactions, hyporheic zone, McMurdo Dry Valleys, nitrogen cycling, particulate organic matter},
	doi = {10.1029/2020JG006097},
	url = {https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2020JG006097},
	author = {Heindel, Ruth C and Darling, Joshua P. and Singley, Joel G. and Bergstrom, Anna J. and Diane M. McKnight and Lukkari, Braeden M. and Kathleen A. Welch and Michael N. Gooseff}
}
@article {4244,
	title = {Diurnal chemistry of two contrasting stream types, Taylor Valley, McMurdo Dry Valley Region, Antarctica},
	journal = {E3S Web of Conferences},
	volume = {98},
	year = {2019},
	month = {06/2019},
	abstract = {<p>Numerous ephemeral streams flow within the McMurdo Dry Valley Region of Antarctica that transport glacial meltwater to perennially ice-covered, closed-basin lakes during the austral summer. The diurnal behavior for two Taylor Valley streams of different character was examined during the summer of 2010-11. Andersen Creek is a short, 1st-order proglacial stream, whereas Von Guerard Stream is a long, high-order stream with an extensive hyporheic zone that has a substantial cyanobacterial algal mat community in its middle reaches. Both streams display strong daily cycles for temperature, electrical conductivity, dissolved oxygen, and pH. Conductivity varies in concert with flow, with solute dilution occurring during the daily high-flow pulse. Dissolved oxygen co-varies strongly with pH at Andersen Creek but not for Von Guerard Stream. Each stream has a distinct geochemical character that for Andersen Creek is a direct reflection of its glacial source, unmodified by secondary effects, whereas that for Von Guerard Stream is modulated by its resident algal mat community and through extensive hyporheic zone interaction and exchange.</p>},
	keywords = {LTER-MCM},
	doi = {10.1051/e3sconf/20199801020},
	url = {https://www.e3s-conferences.org/articles/e3sconf/abs/2019/24/e3sconf_wri-162018_01020/e3sconf_wri-162018_01020.html},
	author = {Harmon, Mark E. and Leslie, D.L. and W. Berry Lyons and Kathleen A. Welch and Diane M. McKnight},
	editor = {Chudaev, O. and Kharaka, Y. and Harmon, R.S. and Millot, R. and Shouakar-Stash, O.}
}
@article {1082,
	title = {Do Cryoconite Holes have the Potential to be Significant Sources of C, N, and P to Downstream Depauperate Ecosystems of Taylor Valley, Antarctica?},
	journal = {Arctic, Antarctic, and Alpine Research},
	volume = {45},
	year = {2013},
	month = {11/2013},
	pages = {440 - 454},
	keywords = {LTER-MCM},
	doi = {10.1657/1938-4246-45.4.440},
	author = {Bagshaw, Elizabeth and Martyn Tranter and Andrew G Fountain and Kathleen A. Welch and Hassan J. Basagic and W. Berry Lyons}
}
@article {1294,
	title = {Dating water and solute additions to ice-covered Antarctic lakes},
	journal = {Geochimica et Cosmochimica Acta},
	volume = {69},
	year = {2005},
	pages = {A720},
	keywords = {LTER-MCM},
	author = {W. Berry Lyons and Carolyn Dowling and Kathleen A. Welch and Snyder, G and Robert J. Poreda and Peter T. Doran and Andrew G Fountain}
}
@inbook {1552,
	title = {Determination of rare earth elements in Antarctic lakes and streams of varying ionic strengths},
	booktitle = {Plasma Source Mass Spectrometry: Developments and Applications},
	year = {1997},
	pages = {253-262},
	publisher = {Royal Society of Chemistry},
	organization = {Royal Society of Chemistry},
	address = {London},
	keywords = {LTER-MCM},
	author = {Graham, E and Ramsey, L. A. and W. Berry Lyons and Kathleen A. Welch}
}
@article {1569,
	title = {Determination of major element chemistry in terrestrial waters from Antarctica by ion chromatography},
	journal = {Journal of Chromatography A},
	volume = {739},
	year = {1996},
	pages = {257-263},
	keywords = {LTER-MCM},
	author = {Kathleen A. Welch and W. Berry Lyons and Graham, E and Klaus Neumann and James M.  Thomas and D. Mikesell}
}
