ORCID Profile
0000-0001-7213-521X
Current Organisations
Colorado State University
,
National High Magnetic Field Laboratory
Does something not look right? The information on this page has been harvested from data sources that may not be up to date. We continue to work with information providers to improve coverage and quality. To report an issue, use the Feedback Form.
Publisher: Springer Science and Business Media LLC
Date: 20-04-2022
DOI: 10.1038/S41467-022-29711-9
Abstract: Groundwater comprises 95% of the liquid fresh water on Earth and contains a erse mix of dissolved organic matter (DOM) molecules which play a significant role in the global carbon cycle. Currently, the storage times and degradation pathways of groundwater DOM are unclear, preventing an accurate estimate of groundwater carbon sources and sinks for global carbon budgets. Here we reveal the transformations of DOM in aging groundwater using ultra-high resolution mass spectrometry combined with radiocarbon dating. Long-term anoxia and a lack of photodegradation leads to the removal of oxidised DOM and a build-up of both reduced photodegradable formulae and aerobically biolabile formulae with a strong microbial signal. This contrasts with the degradation pathway of DOM in oxic marine, river, and lake systems. Our findings suggest that processes such as groundwater extraction and subterranean groundwater discharge to oceans could result in up to 13 Tg of highly photolabile and aerobically biolabile groundwater dissolved organic carbon released to surface environments per year, where it can be rapidly degraded. These findings highlight the importance of considering groundwater DOM in global carbon budgets.
Publisher: American Chemical Society (ACS)
Date: 06-10-2021
Publisher: Elsevier BV
Date: 03-2020
Publisher: Elsevier BV
Date: 02-2020
DOI: 10.1016/J.WATRES.2019.115201
Abstract: Dissolved organic matter (DOM) in groundwater is fundamentally important with respect to biogeochemical reactions, global carbon cycling, heavy metal transport, water treatability and potability. One source of DOM to groundwater is from the transport of organic matter from the vadose zone by rainfall recharge. Changes in precipitation patterns associated with natural climate variability and climate change are expected to alter the load and character of organic matter released from these areas, which ultimately impacts on groundwater quality and DOM treatability. In order to investigate potential changes in groundwater DOM character after rainfall recharge, we s led shallow groundwater from a coastal peat-rich sand aquifer in New South Wales, Australia, during an extended period of low precipitation (average daily precipitation rate < 1.6 mm day
Publisher: Proceedings of the National Academy of Sciences
Date: 09-07-2018
Abstract: The oceans of Earth’s middle age, 1.8–0.8 billion years ago, were devoid of animal-like life. According to one hypothesis, the emergence of large, active organisms was restrained by the limited supply of large food particles such as algae. Through the discovery of molecular fossils of the photopigment chlorophyll in 1.1-billion-year-old marine sedimentary rocks, we were able to quantify the abundance of different phototrophs. The nitrogen isotopic values of the fossil pigments showed that the oceans were dominated by cyanobacteria, while larger planktonic algae were scarce. This supports the hypothesis that small cells at the base of the food chain limited the flow of energy to higher trophic levels, potentially retarding the emergence of large and complex life.
Location: United States of America
No related grants have been discovered for Amy McKenna.