The spatial and interannual dynamics of the surface water carbonate system and air–sea CO<sub>2</sub> fluxes in the outer shelf and slope of the Eurasian Arctic Ocean
The Arctic is undergoing dramatic changes which cover the entire range of natural processes, from extreme increases in the temperatures of air, soil, and water, to changes in the cryosphere, the biodiversity of Arctic waters, and land vegetation. Small changes in the largest marine carbon pool,...
| Main Authors: | , , , , , , , , , , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2017-11-01
|
| Series: | Ocean Science |
| Online Access: | https://www.ocean-sci.net/13/997/2017/os-13-997-2017.pdf |
| Summary: | The Arctic is undergoing dramatic changes which cover the entire
range of natural processes, from extreme increases in the temperatures of
air, soil, and water, to changes in the cryosphere, the biodiversity of
Arctic waters, and land vegetation. Small changes in the largest marine
carbon pool, the dissolved inorganic carbon pool, can have a profound impact
on the carbon dioxide (CO<sub>2</sub>) flux between the ocean and the atmosphere,
and the feedback of this flux to climate. Knowledge of relevant processes in
the Arctic seas improves the evaluation and projection of carbon cycle
dynamics under current conditions of rapid climate change.
<br><br>
Investigation of the CO<sub>2</sub> system in the outer shelf and continental slope
waters of the Eurasian Arctic seas (the Barents, Kara, Laptev, and East
Siberian seas) during 2006, 2007, and 2009 revealed a general trend in the
surface water partial pressure of CO<sub>2</sub> (<i>p</i>CO<sub>2</sub>) distribution, which
manifested as an increase in <i>p</i>CO<sub>2</sub> values eastward. The existence of
this trend was defined by different oceanographic and biogeochemical regimes
in the western and eastern parts of the study area; the trend is likely
increasing due to a combination of factors determined by contemporary change
in the Arctic climate, each change in turn evoking a series of synergistic
effects. A high-resolution in situ investigation of the carbonate system
parameters of the four Arctic seas was carried out in the warm season of
2007; this year was characterized by the next-to-lowest historic sea-ice extent in
the Arctic Ocean, on satellite record, to that date. The study showed the
different responses of the seawater carbonate system to the environment
changes in the western vs. the eastern Eurasian Arctic seas. The large, open,
highly productive water area in the northern Barents Sea enhances atmospheric
CO<sub>2</sub> uptake. In contrast, the uptake of CO<sub>2</sub> was strongly weakened in
the outer shelf and slope waters of the East Siberian Arctic seas under the
2007 environmental conditions. The surface seawater appears in equilibrium or
slightly supersaturated by CO<sub>2</sub> relative to atmosphere because of the
increasing influence of river runoff and its input of terrestrial organic
matter that mineralizes, in combination with the high surface water
temperature during sea-ice-free conditions.
<br><br>
This investigation shows the importance of processes that vary on small
scales, both in time and space, for estimating the air–sea exchange of
CO<sub>2</sub>. It stresses the need for high-resolution coverage of ocean
observations as well as time series. Furthermore, time series must include
multi-year studies in the dynamic regions of the Arctic Ocean during these
times of environmental change. |
|---|---|
| ISSN: | 1812-0784 1812-0792 |