title: Spatial and temporal variability ofAlexandriumcyst fluxes in the Gulf of Maine: Relationship to seasonal particle export and resuspension.
abstract: Quantification ofAlexandriumcyst fluxes through the Gulf of Maine water column is central to understanding the linkage between the source and fate of annualAlexandriumblooms in the offshore waters. These blooms often lead to paralytic shellfish poisoning (PSP) and extensive closures of shellfish beds. We report here on time-series sediment trap deployments completed at four offshore locations in the gulf between 2005 and 2010 as components of two ECOHAB-GOM field programs. Data presented documents the substantial spatial and temporal fluctuations inAlexandrium fundyensecyst fluxes in the gulf. Cyst delivery out of the euphotic zone peaked primarily between July and August following annual spring-summerAlexandriumblooms and was greatest in the western gulf. At all sites, cyst flux maxima to the subsurface waters were rarely coincident with seasonal peaks in the total mass export of particulate material indicating that cyst delivery was primarily via individually sinking cysts. Where persistent benthic nepheloid layers (BNLs) exist, significant sediment resuspension input of cysts to the near-bottom water column was evidenced by deep cyst fluxes that were up to several orders of magnitude greater than that measured above the BNL. The largest cyst fluxes in the BNL were observed in the eastern gulf, suggesting greater resuspension energy and BNL cyst inventories in this region. Temporal similarities between peak cyst export out of the upper ocean and peak cyst fluxes in the BNL were observed and document the contribution of seasonal, newly formed cysts to the BNL. The data however also suggest that manyAlexandriumcells comprising the massive, short-lived blooms do not transition into cysts. Time-series flow measurements and a simple 1D model demonstrate that the BNL cyst fluxes reflect the combined effects of tidal energy-maintained resuspension, deposition, and input of cysts from the overlying water column.
authors.affiliation: School for Marine Science and Technology, University of Massachusetts Dartmouth, New Bedford, MA 02744, USA.
authors.forename: C H
authors.initials: CH
authors.lastname: Pilskaln
authors.affiliation: Woods Hole Oceanographic Institution, Woods Hole, MA 02543, USA.
authors.forename: D M
authors.initials: DM
authors.lastname: Anderson
authors.affiliation: Woods Hole Oceanographic Institution, Woods Hole, MA 02543, USA.
authors.forename: D J
authors.initials: DJ
authors.lastname: McGillicuddy
authors.affiliation: Woods Hole Oceanographic Institution, Woods Hole, MA 02543, USA.
authors.forename: B A
authors.initials: BA
authors.lastname: Keafer
authors.affiliation: School for Marine Science and Technology, University of Massachusetts Dartmouth, New Bedford, MA 02744, USA.
authors.forename: K
authors.initials: K
authors.lastname: Hayashi
authors.affiliation: Woods Hole Oceanographic Institution, Woods Hole, MA 02543, USA.
authors.forename: K
authors.initials: K
authors.lastname: Norton
keywords: Alexandrium; Cysts; Gulf of Maine; Particulate flux; Resuspension; Sediment traps