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Where I work 期刊论文
NATURE, 2020, 582 (7813) : 600-600
作者:  Bodin, Madeline;  Khan, Christin
收藏  |  浏览/下载:11/0  |  提交时间:2020/07/03

US federal biologist Christin Khan embraces risk above the Atlantic Ocean to monitor a rare species.


US federal biologist Christin Khan embraces risk above the Atlantic Ocean to monitor a rare species.


  
Hydrothermal (NN)-N-15-N-15 abundances constrain the origins of mantle nitrogen 期刊论文
NATURE, 2020, 580 (7803) : 367-+
作者:  Zhao, Steven;  Jang, Cholsoon;  Liu, Joyce;  Uehara, Kahealani;  Gilbert, Michael;  Izzo, Luke;  Zeng, Xianfeng;  Trefely, Sophie;  Fernandez, Sully;  Carrer, Alessandro;  Miller, Katelyn D.;  Schug, Zachary T.;  Snyder, Nathaniel W.;  Gade, Terence P.;  Titchenell, Paul M.;  Rabinowitz, Joshua D.;  Wellen, Kathryn E.
收藏  |  浏览/下载:16/0  |  提交时间:2020/05/13

Nitrogen is the main constituent of the Earth'  s atmosphere, but its provenance in the Earth'  s mantle remains uncertain. The relative contribution of primordial nitrogen inherited during the Earth'  s accretion versus that subducted from the Earth'  s surface is unclear(1-6). Here we show that the mantle may have retained remnants of such primordial nitrogen. We use the rare (NN)-N-15-N-15 isotopologue of N-2 as a new tracer of air contamination in volcanic gas effusions. By constraining air contamination in gases from Iceland, Eifel (Germany) and Yellowstone (USA), we derive estimates of mantle delta N-15 (the fractional difference in N-15/N-14 from air), N-2/Ar-36 and N-2/He-3. Our results show that negative delta N-15 values observed in gases, previously regarded as indicating a mantle origin for nitrogen(7-10), in fact represent dominantly air-derived N-2 that experienced N-15/N-14 fractionation in hydrothermal systems. Using two-component mixing models to correct for this effect, the (NN)-N-15-N-15 data allow extrapolations that characterize mantle endmember delta N-15, N-2/Ar-36 and N-2/He-3 values. We show that the Eifel region has slightly increased delta N-15 and N-2/Ar-36 values relative to estimates for the convective mantle provided by mid-ocean-ridge basalts(11), consistent with subducted nitrogen being added to the mantle source. In contrast, we find that whereas the Yellowstone plume has delta N-15 values substantially greater than that of the convective mantle, resembling surface components(12-15), its N-2/Ar-36 and N-2/He-3 ratios are indistinguishable from those of the convective mantle. This observation raises the possibility that the plume hosts a primordial component. We provide a test of the subduction hypothesis with a two-box model, describing the evolution of mantle and surface nitrogen through geological time. We show that the effect of subduction on the deep nitrogen cycle may be less important than has been suggested by previous investigations. We propose instead that high mid-ocean-ridge basalt and plume delta N-15 values may both be dominantly primordial features.


  
Tracking of marine predators to protect Southern Ocean ecosystems 期刊论文
NATURE, 2020
作者:  Kim, Eugene;  Kerssemakers, Jacob;  Shaltiel, Indra A.;  Haering, Christian H.;  Dekker, Cees
收藏  |  浏览/下载:19/0  |  提交时间:2020/07/03

Tracking data from 17 marine predator species in the Southern Ocean are used to identify Areas of Ecological Significance, the protection of which could help to mitigate increasing pressures on Southern Ocean ecosystems.


Southern Ocean ecosystems are under pressure from resource exploitation and climate change(1,2). Mitigation requires the identification and protection of Areas of Ecological Significance (AESs), which have so far not been determined at the ocean-basin scale. Here, using assemblage-level tracking of marine predators, we identify AESs for this globally important region and assess current threats and protection levels. Integration of more than 4,000 tracks from 17 bird and mammal species reveals AESs around sub-Antarctic islands in the Atlantic and Indian Oceans and over the Antarctic continental shelf. Fishing pressure is disproportionately concentrated inside AESs, and climate change over the next century is predicted to impose pressure on these areas, particularly around the Antarctic continent. At present, 7.1% of the ocean south of 40 degrees S is under formal protection, including 29% of the total AESs. The establishment and regular revision of networks of protection that encompass AESs are needed to provide long-term mitigation of growing pressures on Southern Ocean ecosystems.


  
Climate change and overfishing increase neurotoxicant in marine predators 期刊论文
NATURE, 2019, 572 (7771) : 648-+
作者:  Schartup, Amina T.;  Thackray, Colin P.;  Qureshi, Asif;  Dassuncao, Clifton;  Gillespie, Kyle;  Hanke, Alex;  Sunderland, Elsie M.
收藏  |  浏览/下载:5/0  |  提交时间:2019/11/27
Abyssal ocean overturning shaped by seafloor distribution 期刊论文
NATURE, 2017, 551 (7679) : 181-+
作者:  de lavergne, C.;  Madec, G.;  Roquet, F.;  Holmes, R. M.;  McDougall, T. J.
收藏  |  浏览/下载:8/0  |  提交时间:2019/11/27