Table of Contents

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Chlorophyll data associated with salp swarm collections in the Slope Waters off northeastern USA.

Associated datasets: salp_swarms

Seawater was collected with Niskin bottles at several depths and filtered through both GFF filters and 2 µm pore glass fibre filters for analysis of Chlorophyll a and total phaeopigment. Immediately after water samples were filtered, filter pads were transferred into 6 ml of 90% acetone and the pigment was extracted in a dark refrigerator for 24 hours. Filter pads were removed and the test tubes centrifuged just prior to reading the fluorescence. Following the initial fluorescence reading, samples were acidified with ~0.2ml of HCl and reread. The fluorometer was calibrated using a spectrophotometer during each cruise using standard Chl-a derived from spinach. Chlorophyll-a and phaeopigments were calculated from standard equations (Strickland and Parsons 1972).

Salps are holoplanktonic grazers that have a life history, feeding biology and population dynamic strikingly different from copepods or other crustacean zooplankton. They can occur in very dense populations that cover large areas, and these blooms have been shown to have major impacts due to grazing and production of fast?sinking fecal pellets. However the conditions supporting bloom formation, and the energetics, reproduction and behavior of the bloom?forming salps are still poorly understood. This study will focus on two species of salps that are global in their distribution and representative of two genera that commonly form large blooms. Salpa aspera regularly occurs during the summer in high concentrations in the slope waters of the Mid?Atlantic Bight, while Thalia democratica regularly forms dense populations during the winter spring in the Georgia Bight. The investigators will examine feeding, metabolism, growth, reproduction and population dynamics of these salps. They will use two independent modeling approaches, grounded in experimental and field data, to extend their observations to other time and space scales. interpret ouexperimental and modeling results will be interpreted within the context of the environmental conditions to which the salps are exposed. This integrated approach will provide the best basis for understanding how salp blooms form and persist. Results of this study will extend to other species that occur in high densities in many locations, allowing scientists to better evaluate the importance of salps in biogeochemical cycles and in structuring the pelagic environment.