Spatial patterns of zooplankton biomass in the northeast Pacific Ocean

Abstract

We used Mantel's tests and correlograms to statistically detect and describe large-scale spatial patterns during spring and summer in zooplankton biomass in the northeast Pacific Ocean following winters of varying degrees of wind stress. During the spring of 1963, a sampling period following a winter of moderate wlnd stress, we found that sites separated by 1 to 100, 201 to 400 and 1101 to 1200 km had similar biomass levels, and that areas of high biomass occurred around the penphery of the Gulf of Alaska. We found similar results for spring data from other years following winters of high wind stress. During summers following winters of low wind stress, biomass levels were similar among sites within 1 to 100 km of each other, but they were generally lower than the spring values. We did not detect spatial patterns in biomass during spnngs following winters of low wind stress, or during summers following winters of high wind stress. Elevated winter wind stress appeared to favor the formation of discernable spatial patterns In zooplankton blomass during the subsequent spring, but the pattern did not persist into the summer. It appears that spatial patterns ('zooplankton patches' at c400 km scales) may be formed b y meso-scale eddies, while the similarities over larger distance intervals may be attributed to gyre currents and spring bloom dynamics.