Aquatic Sciences Meeting, Albuquerque 2001

CS15 Harmful Algal Blooms

Date: Tuesday, February 13, 2001, Time: 3:00:00 PM

Location: Cochiti/Taos

Dubois, A, , Bowdoin College, Brunswick, USA, adubois@bowdoin.edu

Coe, A, L, University of Maryland, Cambridge, USA, acoe@hpl.umces.edu

MacIntyre, H, L, University of Maryland, Cambridge, USA, macintyr@hpl.umces.edu

STIMULATIVE EFFECT OF SEDIMENT PORE WATER ON THE GROWTH OF THE BLOOM-FORMING DINOFLAGELLATE PROROCENTRUM MINIMUM

Pore water from 18 sites on the Delmarva Peninsula was tested in bioassays for its stimulatory effect on growth of the bloom-forming dinoflagellate Prorocentrum minimum. Concentrations of total dissolved nitrogen, phosphorus and organic carbon (TDN, TDP and DOC) were on average 50-, 10- and 4-fold higher in pore water than in the overlying water column. The TDN and TDP pools were dominated by ammonium and orthophosphate (mean of 93% and 84% molar concentration, respectively). Concentrations of TDN and DOC were highly correlated (p<0.01, R=0.83). Exponential growth rates were calculated from daily changes in fluorescence and were significantly higher than in control media in 15 of the 18 cases, increasing by 33-93%. The enhancement of the exponential growth rate was correlated with the concentration of ammonium and DOC in the pore water addition (p<0.05, R=0.54 and R=0.65). Final cell yields, measured as cell numbers and particulate carbon and nitrogen, increased with pore water additions. The increases were also correlated (p<0.01, R=0.63 and R=0.73) with TDN and DOC, suggesting that those pore waters capable of enhancing growth rate could also increase biomass.

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Aquatic Sciences Meeting, Albuquerque 2001

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