FN Archimer Export Format
PT J
TI Projected Centennial Oxygen Trends and Their Attribution to Distinct Ocean Climate Forcings
BT 
AF TAKANO, Yohei
   ITO, Takamitsu
   DEUTSCH, Curtis
AS 1:1,2;2:1;3:3;
FF 1:;2:;3:;
C1 Georgia Inst Technol, Sch Earth & Atmospher Sci, Atlanta, GA 30332 USA.
   Max Planck Inst Meteorol, Hamburg, Germany.
   Univ Washington, Sch Oceanog, Seattle, WA 98195 USA.
C2 GEORGIA INST TECHNOL, USA
   MAX PLANCK INST METEOROL, GERMANY
   UNIV WASHINGTON, USA
IF 5.733
TC 23
UR https://archimer.ifremer.fr/doc/00675/78682/80883.pdf
LA English
DT Article
CR OISO - OCÉAN INDIEN SERVICE D'OBSERVATION
DE ;oxygen trends;climate change;centennial timescale
AB We explore centennial changes in tropical Pacific oxygen (O-2) using numerical models to illustrate the dominant patterns and mechanisms under centennial climate change. Future projections from state-of-the-art Earth System Models exhibit significant model to model differences, but decreased solubility and weakened ventilation together deplete thermocline O-2 in middle to high latitudes. In contrast, the tropical thermocline O-2 undergoes much smaller changes or even a slight increase. A suite of sensitivity experiments using a coarse resolution ocean circulation and biogeochemistry model show that ocean warming is the leading cause of global deoxygenation in the thermocline across all latitudes with secondary contributions from changes in hydrological cycles and wind stress modulating regional changes in O-2. The small O-2 changes in the tropical Pacific thermocline reflect near-complete compensation between the solubility decrease due to warming and reduction in apparent oxygen utilization (AOU). We further quantified the changes in AOU due to contributions from changes in water mass age and biological remineralization from the sensitivity experiments. The two effects almost equally contribute to the reduction of AOU in the tropical Pacific thermocline (43% for physical circulations and 57% for biology). Our results suggest that better understanding of water mass changes in the tropical oceans is key to improving projections and reducing the uncertainties of future O-2 changes. Plain Language Summary Global warming in the next hundred years could lead to a large amount of oxygen loss from the ocean. This could impact not only the marine ecosystem but also fisheries. We use model simulations to investigate how long-term climate change, such as changes in sea surface temperature, precipitation, and winds, under the anthropogenic transient could impact oceanic oxygen loss in the next hundred years. The ocean loses oxygen in most of the regions but tropical oceans could actually gain oxygen regionally. We investigate what causes these unique oxygen changes in the tropical Pacific Ocean. The counterintuitive oxygen changes in the tropical Pacific Ocean are likely due to, by an almost equal amount of effects, changes in water mass supply due to changes in circulations and changes in biological activity, that is, consumption of oxygen through respiration. Tropical oceans are sensitive to oxygen loss because of its impact on marine ecosystems. Our study could provide a better understanding of future oxygen loss in the ocean.
PY 2018
PD SEP
SO Global Biogeochemical Cycles
SN 0886-6236
PU Amer Geophysical Union
VL 32
IS 9
UT 000447281100005
BP 1329
EP 1349
DI 10.1029/2018GB005939
ID 78682
ER

EF