The Davis Strait - DCE - Nationalt Center for Miljø og Energi

The current warming trends are often linked to anthropogenic carbon dioxide
(CO2) accumulation in the atmospheric. There is also some evidence that
increased CO2 concentrations will reduce ocean pH and carbonate ion concentrations,
and thereby the level of calcium carbonate saturation. If emissions
of CO2 to the atmosphere continue to increase, acidification of the
oceans may cause some calcifying organisms, such as coccolithophores, corals,
echinoderms, molluscs and crustaceans, to have difficulty forming or
maintaining their external calcium carbonate skeletons. Other effects of
ocean acidification on marine organisms could include slower growth, decreased
reproductive potential or increased susceptibility to disease, with
possible implications for ecosystem structure and elemental cycling (e.g.,
Orr et al. 2005, Fabry et al. 2008, Kroeker et al. 2010), also in the assessment
area.
Marine ecosystems in the Arctic region are already changing in response to a
warming climate, as documented by Wassmann et al. (2011). They found
clear evidence for changes for almost all components of the marine ecosystems,
also in West Greenland, ranging from planktonic communities to large
mammals.
Wassmann et al.’s (2011) evaluation is based on several types of footprints of
responses in biota to climate change, such as range shifts, including poleward
range shift of sub-Arctic species, changes in abundance,
growth/condition, behaviour/phenology and community/regime shifts
(Table 8.1.1).
Table 8.1.1. Summary of types of footprints of responses of marine organisms living in the Arctic region to climate change
(Wassmann et al. 2011)
Responses Nature of changes
Range shift Northward displacement of sub-Arctic and temperate species, cross-Arctic transport of organisms
from the Pacific to the Atlantic sectors
Abundance Increased abundance and reproductive output of sub-Arctic species, decline and reduced reproductive
success of some Arctic species associated with the ice, and species now being used as
prey by predators whose preferred prey have declined
Growth and condition Increased growth of some sub-Arctic species and primary producers, and reduced growth and
condition of icebound, ice-associated, or ice-borne animals
Behaviour and phenology Anomalous behaviour of ice-bound, ice-associated, or ice-borne animals with earlier spring phenological
events and delayed autumn events
Community and regime shifts Changes in community structure due to range shifts of predators resulting in changes in the
predator-prey linkages in the trophic network
Some of the ongoing and expected changes and their relevance for the assessment
area are described below.
8.2 Primary production and zooplankton
Currently, marine Arctic ecosystems are dominated by the diatom-feeding
Calanus glacialis and C. hyperboreus; both of which are favoured food for specialised
important seabirds, such as the little auk (Alle alle). A prolonged
production period could favour a mixed diatom-dinoflagellate community,
which could result in a food chain based on Calanus finmarchicus – Metridia
longa, which are less valuable as a food resource for planktivorous birds and
mammals (bowhead whale and little auk). As a result, climate change is likely
to change primary production from strongly pulsed to a more prolonged
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