Arctic Climate Change and Its Impacts on the Ecology of the North Atlantic

Abstract

Abstract. Arctic climate change from the Paleocene epoch to the present is reconstructed with the objective of assessing its recent and future impacts on the ecology of the North Atlantic. A recurring theme in Earth's paleoclimate record is the importance of the Arctic atmosphere, ocean, and cryosphere in regulating global climate on a variety of spatial and temporal scales. A second recurring theme in this record is the importance of freshwater export from the Arctic in regulating global-to basin-scale ocean circulation patterns and climate. Since the 1970s, historically unprecedented changes have been observed in the Arctic as climate warming has increased precipitation, river discharge, and glacial as well as sea-ice melting. In addition, modal shifts in the atmosphere have altered Arctic Ocean circulation patterns and the export of freshwater into the North Atlantic. The combination of these processes has resulted in variable patterns of freshwater export from the Arctic Ocean and the emergence of salinity anomalies that have periodically freshened waters in the North Atlantic. Since the early 1990s, changes in Arctic Ocean circulation patterns and freshwater export have been associated with two types of ecological responses in the North Atlantic. The first of these responses has been an ongoing series of biogeographic range expansions by boreal plankton, including renewal of the trans-Arctic exchanges of Pacific species with the Atlantic. The second response was a dramatic regime shift in the shelf ecosystems of the Northwest Atlantic that occurred during the early 1990s. This regime shift resulted from freshening and stratification of the shelf waters, which in turn could be linked to changes in the abundances and seasonal cycles of phytoplankton, zooplankton, and higher trophic-level consumer populations. It is predicted that the recently observed ecological responses to Arctic climate change in the North Atlantic will continue into the near future if current trends in sea ice, freshwater export, and surface ocean salinity continue. It is more difficult to predict ecological responses to abrupt climate change in the more distant future as tipping points in the Earth's climate system are exceeded.

Synchronous marine pelagic regime shifts in the Northern Hemisphere

“…These correlations might indicate a specific role of the Arctic area, which has been shown to influence both North Pacific and North Atlantic ecosystems [76,77].…”

“…The first of these resulted in the Great Salinity Anomaly of the 1990s, characterized by the discharge of relatively low-salinity water from the Arctic Ocean into the North Atlantic through the Canadian Arctic Archipelago and Fram Strait (between Greenland and Svalbard) [41,76]. North Atlantic circulation (increased discharge of relatively low-salinity water into the North Atlantic, and redirection of the shallow, low-salinity outflow from the Arctic Ocean mainly through the Labrador Sea [41,76]). The Pacific Ocean circulation is also influenced by the Arctic circulation [97] and by the AO.…”

Recent Arctic Climate Change and Its Remote Forcing of Northwest Atlantic Shelf Ecosystems

“…that have been documented since the late 1960s (Belkin et al, 1998;Belkin, 2004;Greene et al, 2008). All of these , 1997;Dukhovskoy et al, 2006;Mclaughlin et al, 2011).…”

Responses of Low Arctic Stream Benthic Macroinvertebrate Communities to Environmental Drivers at Nested Spatial Scales

“…Despite the relatively low levels of warming that have occurred in our study area to date (Prowse et al, 2006a), recent models have suggested that the Labrador Sea may be particularly sensitive to warming-related shifts in circulation and salinity, and this may impact inland waters in northern Labrador and Québec (Greene et al, 2008). The results of our study indicate the importance of monitoring environmental variables along the full extent of the hierarchical framework to detect impacts from future warming.…”