Physical constrains and productivity in the future Arctic Ocean

Abstract

Today's physical oceanography and primary and secondary production was investigated for the entire Arctic Ocean (AO) with the physical-biologically coupled SINMOD model. To obtain indications on the effect of climate change in the twenty-first century the magnitude of change, and where and when these may take place SINMOD was forced with down-scaled climate trajectories of the International Panel of Climate Change with the A1B climate scenario which appears to predict an average global atmospheric temperature increase of 3.5-4 • C at the end of this century. It is projected that some surface water features of the physical oceanography in the AO and adjacent regions will change considerably. The largest changes will occur along the continuous domains of Pacific and in particular regarding Atlantic Water (AW) advection and the inflow shelves. Withdrawal of ice will increase primary production, but stratification will persist or, for the most, get stronger as a function of ice-melt and thermal warming along the inflow shelves. Thus, the nutrient dependent new and harvestable production will not increase proportionally with increasing photosynthetic active radiation (PAR). The greatest increases in primary production are found along the Eurasian perimeter of the AO (up to 40 g C m −2 y −1 ) and in particular in the northern Barents and Kara Seas (40-80 g C m −2 y −1 ) where less ice-cover implies less Arctic Water (ArW) and thus less stratification. Along the shelf break engirdling the AO upwelling and vertical mixing supplies nutrients to the euphotic zone when ice-cover withdraws northwards. The production of Arctic copepods along the Eurasian perimeter of the AO will increase significantly by the end of this century (2-4 g C m −2 y −1 ). Primary and secondary production will decrease along the southern sections of the continuous advection domains of Pacific and AW due to increasing thermal stratification. In the central AO primary production will not increase much due to stratification-induced nutrient limitation.

Patterns and drivers of megabenthic secondary production on the Barents Sea shelf

“…Simultaneously, primary and secondary production in the southern, ice-free regions might decrease as well, due to increasing thermal stratification (Slagstad et al 2015). Accordingly, we expect cascading effects of these changes on all levels of the Barents Sea ecosystem.…”

Assessing Phytoplankton Activities in the Seasonal Ice Zone of the Greenland Sea Over an Annual Cycle

“…The SINMOD model (Slagstad et al, ), a 3‐D physical‐biogeochemical coupled model was used to test the assumption that horizontal fluxes were not the main factor influencing changes in [NO 3 ] between 2012 and 2014. For this, the observed [NO 3 ] in the surface layer (0–25 m) in 2012 and 2014 was compared to the simulated surface (0–25 m) [NO 3 ] at the mean position of BGC‐Argo floats and to the monthly flux of nitrate inside the surface layer (0–25 m) through three sections located near the BGC‐Argo float positions (Figure S3): two west‐east sections (between 10°W and 20°W, at 73.5°N in 2014, and 72.4°N in 2012) and one north‐south section (between 71°N and 75°N, at 15°W).…”

“…This method assumes the advective fluxes (horizontal and vertical) as negligible, suggesting that biological processes dominate the nitrate changes over a seasonal time scale and a large area (as the one covered by the float over a year). However, to estimate the relative influence of such physical processes on the NCP estimations, two different models were used: the bulk mixed layer model of Glover et al (, named PWP model, originally developed by Price et al, ) and a coupled 3‐D hydrodynamic‐ecological model system named SINMOD (Slagstad et al, ), the last one specifically tuned for the Arctic Ocean, particularly its Atlantic side.…”

Net primary productivity estimates and environmental variables in the Arctic Ocean: An assessment of coupled physical-biogeochemical models

“…Forcing fields includes atmospheric forcing from the ERA-Interim reanalysis (http://www.ecmwf.int) [Dee et al, 2011], tides from TPXO 6.2 model prescribed at open boundaries, and freshwater run-off from R-ArcticNet (http://www.r-arcticnet.sr.unh.edu/). More details of the recent updates of SINMOD and the model setup may be found in Slagstad et al [2015].…”