Sastri A.R.,National Taiwan University |
Nelson R.J.,Fisheries and Oceans Canada Institute of Ocean science |
Nelson R.J.,University of Victoria |
Varela D.E.,University of Victoria |
And 3 more authors.
Journal of Experimental Marine Biology and Ecology | Year: 2012
Community-level estimates of mesozooplankton productivity are required for calculating the magnitude and efficiency of energy flow through planktonic food webs. However, estimates of biomass production rates (BP) for entire crustacean zooplankton communities are lacking, because conventional field methodology is difficult to apply at the community level. We measured community-level BP using the chitobiase method in an area extending from the west coast of British Columbia, Canada, across the Bering and Chukchi Seas and into the western Beaufort Sea (July 2008, October 2008, and July 2009). Our objective was to measure zooplankton productivity on a scale that was sufficiently broad to allow us to assess the sensitivity of the method to a wide variety of conditions. Overall, variations in temperature and phytoplankton biomass explained 67% of the observed variation in BP. Crustacean zooplankton BP values estimated during July 2008 and 2009 on the Bering Sea shelf were comparable to estimates from one of the very few community-level estimates for this expansive region. Our estimates of the average individual growth rate (daily P/B) for crustacean zooplankton were also comparable to model predictions and direct estimates for the biomass-dominant copepod species in the northern Gulf of Alaska. These observations suggest that the chitobiase method can be used to measure useful estimates of community-level crustacean zooplankton productivity under a broad range of conditions and also provides the basis for further refinement of the technique. © 2012 Elsevier B.V.