Current state and trends in Canadian Arctic marine ecosystems: II. Heterotrophic food web, pelagic-benthic coupling, and biodiversity

Abstract

As part of the Canadian contribution to the International Polar Year (IPY), several major international research programs have focused on offshore arctic marine ecosystems. The general goal of these projects was to improve our understanding of how the response of arctic marine ecosystems to climate warming will alter food web structure and ecosystem services provided to Northerners. At least four key findings from these projects relating to arctic heterotrophic food web, pelagic-benthic coupling and biodiversity have emerged: (1) Contrary to a long-standing paradigm of dormant ecosystems during the long arctic winter, major food web components showed relatively high level of winter activity, well before the spring release of ice algae and subsequent phytoplankton bloom. Such phenological plasticity among key secondary producers like zooplankton may thus narrow the risks of Climatic Change

Multivariate benthic ecosystem functioning in the Arctic – benthic fluxes explained by environmental parameters in the southeastern Beaufort Sea

“…2 or Table 2) was similar to those reported earlier from the region (2003)(2004)2008) (Darnis et al, 2012;Link et al, 2011;Renaud et al, 2007b). All those studies reported highest uptake off the Mackenzie Delta and the Cape Bathurst polynya.…”

“…Benthic boundary fluxes of silicic acid, oxygen and phosphate in 2009 were in the range of those reported for the region in 2008 (Darnis et al, 2012). It is noteworthy that phosphate was released from shallow Mackenzie Shelf sediments during the upwelling year 2008 and that notably less silicic acid was remineralised in the Cape Bathurst polynya area in 2008.…”

“…Determining the spatial variation and partition between source fluxes from and sink fluxes to the sediments is important for improving our understanding of regional biogeochemical cycles (Ebenhöh et al, 1995;Zabel and Hensen, 2006) and, hence, the overall ecosystem functioning. Only few data are available from the Arctic regions, which are particularly sensitive to climate change (Chang and Devol, 2009;Darnis et al, 2012;Davenport et al, 2012;Rysgaard et al, 1998). Due to the more costly collection of nutrient flux data, oxygen uptake is often used as a proxy of total benthic ecosystem functioning, more precisely of activity and benthic remineralisation function (Glud, 2008;Hensen et al, 2006;Holstein and Hensen, 2010;Wenzhöfer and Glud, 2002).…”

Status and trends in the structure of Arctic benthic food webs

“…A decline in spawning and foraging areas will affect both predators and their prey. For instance, polar cod (Boreogadus saida) abundance might be significantly reduced, with tremendous consequences to the entire system as this species is believed to account for up to 75% of energy transfer between zooplankton and vertebrate predators (Darnis et al 2012). In addition to changes in resource availability, top predators will likely face increased complexity within food webs that tend to dissipate energy flow (Węsławski et al 2009).…”

Impacts of Intraguild Predation on Arctic Copepod Communities

“…(1.1 mm) (Darnis et al, 2012). Following the current dynamics, the boreal species C. finmarchicus is also regularly found in marginal Arctic seas, especially in the eastern Greenland Sea and Barents Sea (Conover and Huntley, 1991).…”