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Increased nutrients from aeolian‐dust and riverine origin decrease the CO 2 ‐sink capacity of coastal South Atlantic waters under UVR exposure
Author(s) -
Cabrerizo Marco J.,
Carrillo Presentación,
Villafañe Virginia E.,
MedinaSánchez Juan Manuel,
Helbling E. Walter
Publication year - 2018
Publication title -
limnology and oceanography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.7
H-Index - 197
eISSN - 1939-5590
pISSN - 0024-3590
DOI - 10.1002/lno.10764
Subject(s) - environmental science , sink (geography) , aeolian processes , plankton , nutrient , ecosystem , oceanography , dominance (genetics) , carbon sink , climate change , ecology , atmospheric sciences , geology , biology , geography , biochemistry , cartography , geomorphology , gene
Increases in ultraviolet radiation (UVR) levels due to the ongoing stratification of water bodies and higher nutrient concentrations either through riverine or aeolian‐dust‐inputs are expected in the near future in coastal surface waters. Here, we combined remote‐sensing data of particulate organic carbon (POC; 1997–2016 period), observational data of solar radiation (1999–2015 period), and a mid‐term experimental approach with coastal plankton communities from South Atlantic Ocean (SAO) to test how the interaction between increased nutrients by riverine and aeolian‐dust inputs and high UVR may alter the community dynamics and the CO 2 sink capacity of these ecosystems in the future. Our results show a decline ∼ 27% in the sink capacity of the coastal ecosystems regardless of the nutrient source considered and under high UVR levels. This decreased CO 2 uptake was coupled with a high dynamic photoinhibition and dark recovery of photosystem II and shifts in the community structure toward the dominance by nano‐flagellates. Moreover, remote‐sensing data also evidences an incipient tipping point with decreasing POC values in this area over the annual planktonic succession. Therefore, we propose that to continue this climate and human‐mediated pressure, these metabolic responses could be strengthened and extended to other productive coastal areas.