Zooplankton biogeography as a measure of oceanographic change in Canada Basin (Arctic) Brian Hunt 1, John Nelson 2, Fiona McLaughlin 2, Eddy Carmack 2 1. Earth and Ocean Sciences, University of British Columbia 2. Institute of Ocean Sciences, Sidney, BC

Arctic Climate Change Sea ice cover has declined at a rate of 11% per decade from Sea ice extent in September 2007 was 37% less than the climatological average for the same period (Comiso et al., 2008).

International Polar Year – March 2007 to March Institute of Ocean Sciences Canada’s Three Oceans (C3O) Aims: 1.Produce a comprehensive view of the physical and biological structure of sub-Arctic and Arctic waters around Canada 2.Use this information as a scientific basis for a long-term Arctic Ocean monitoring strategy

“Address change within ocean domains, identify gateways and barriers, and evaluate the stability of boundaries separating juxtaposed oceanic domains.” C3O Mandate

C3O sampling

Use zooplankton biogeography, a combination of taxonomic composition and genetic population structure, to gain insight into biological advection processes between the Arctic, Atlantic and Pacific oceans. A key directive

Zooplankton Biogeography sensitive to environmental parameters e.g. o C, S low mobility short life histories Excellent indicators of environmental change

Changing plankton distributions in the North Sea and North Atlantic Beaugrand et al 2002

Arctic water masses

Pacific and Atlantic Oceans have distinct zooplankton communities which can be used to trace water masses Focus on calanoid copepods North Pacific and Bering Sea Eucalanus bungii Neoclanus cristatus Metridia pacifica Calanus marshallae Acartia longiremis Atlantic Calanus finmarchicus Expatriate species are not reproductively active in Arctic waters, and so populations have to be constantly replenished

Samples collected Additional samples also collected in 2002, 2003, 2004, more to be collected in 2009

Occurrence of indicator species Observations in 2002 Eucalanus bungii Neocalanus cristatus (Hopcroft et al 2005) Calanus marshallae Banks island (Frost 1976) * None observed in 2007 samples *

Genetic analysis: Species population structure Distribution of H1 (Arctic) and H2 (Bering Sea) Calanus glacialis Nelson et al. (in press)

Major zooplankton groups Abundance: dominated by calanoid copepods (small and large), Oithona, and pteropods Biomass: dominated by large calanoid copepods, pteropods, chaetognaths

Ecosystem Structure Analysis of within year spatial patterns in zooplankton community structure in relation to measured physical and biological variables will provide insight into the consequences of environmental change An important question is “What causes between station variance?”

Pteropods and Acidification Limacina helicina Photo: Ricardo Giesecke Clione limacina

Role of pteropods in the Arctic Ocean Pan-Arctic Transect (Thiabault et al 1999) - pteropods were particularly important in Canada Basin (~8% of zooplankton) In this study Pteropods averaged 14% but up to 42% of zooplankton Important grazers and dietary components Melting of sea ice dilutes surface seawater and decreases alkalinity Aragonite under-saturated in surface waters in eastern Canada Basin in 2008

Summary The zooplankton component of C3O: 1. Use zooplankton biogeography to monitor changing ocean circulation (may be best resolved though population genetics) 2. Provide baseline information on the structure of the pelagic ecosystem, and its physical and biological drivers Insights into the affects of: - Sea-ice loss e.g. albedo, wind induced mixing, contribution of sea ice vs pelagic algae to food web - Ocean warming - Acidification