Darcy J. Lonsdale

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Microplankton abundances and phytoplankton mortality rates were determined at six stations during four cruises spanning three seasons in the Ross Sea polynya, Antarctica (early spring, Oct.}Nov. 1996; mid-late summer, Jan.}Feb. 1997; fall, Apr. 1997; mid-late spring, Nov.}Dec. 1997). Rates of microzooplankton herbivory were measured using a modi"ed dilution(More)
We investigated predation rates of small copepods, primarily species of Oithona, on microprotozooplankton and net growth rates of these prey at several locations in the Ross Sea, Antarctica, during an austral summer (January 1997; US JGOFS Process Study II). Ciliates, particularly non-loricate ciliates, contributed substantially to the carbon ration of(More)
Aureococcus anq~ha&erens is a picoplanktonic alga that since 1985 has bloomed in coastal embayments of the western mid-Atlantic, ranging from Narragansett Bay, Rhode Island, to Barnegat Bay, New Jersey, with greatest incidence of rccurrencc in Long Island bays, New York. Blooms of this small alga, referred to as “brown tide,” can persist for several months(More)
We studied the effects of attached peritrich ciliates on the fitness of natural populations of Acartia hudsonica (Pinhey) in Stony Brook Harbor, Long Island Sound. Ciliate infection occurred during late spring, and ciliate load (No. ind.-‘) was not related to copepod age, stage, or body size. Simulated in situ experiments conducted throughout the period of(More)
Phototrophic and heterotrophic nanoplankton (PNAN, HNAN; 2–20 mm protists) and microplankton (PMIC, HMIC; 20–200 mm protists and micrometazoa) are major taxa involved in partitioning carbon and energy within the pelagic food web. In the Ross Sea, Antarctica, plankton biomass appears to be controlled by the seasonal recession of the sea ice and the formation(More)
A method was developed for the rapid detection and enumeration of Aureococcus anophagefferens, the cause of harmful algal blooms called "brown tides" in estuaries of the Mid-Atlantic United States. The method employs a monoclonal antibody (MAb) and a colorimetric, enzyme-linked immunosorbent assay format. The MAb obtained exhibits high reactivity with A.(More)
Experiments were conducted with natural plankton assemblages from two areas in Great South Bay (GSB) and the Peconic Bays Estuary System, NY, to compare the rates of growth and pelagic grazing mortality of Aureococcus anophagefferens with co-occurring phytoplankton. We hypothesized that A. anophagefferens would experience low mortality rates by microbial(More)
Three experiments were carried out in 300 l mesocosms using natural seawater from the Peconic Bays ecosystem, Long Island, New York, to examine the ability of the northern quahog Mercenaria mercenaria to prevent blooms of the brown tide alga Aureococcus anophagefferens. Nutrient enrichment and mixing of the mesocosms was conducted according to previous(More)
Toxic attributes of the brown tide alga Aureococcus anophagefferens affect the ability of benthic and protistan grazers to control blooms. Yet, little is known regarding the effect of A. anophagefferens on a dominant component of the microzooplankton community, copepod nauplii. This study describes the grazer–prey relationship between nauplii of the(More)
Bivalve and microzooplankton community grazing on natural plankton assemblages were studied in 2 embayments of the Peconic Bay estuary (West Neck Bay, Long Island, New York) to determine the relative importance of each community on plankton mortality. Each embayment was characterized by a fringing salt marsh. The bivalve populations consisted of a(More)