Physiological and Behavioral Diagnostics of Nitrogen Limitation for the Toxic Dinoflagellate Alexandrium fundyense
Abstract
One challenge in phytoplankton ecology is to measure species-specific physiological responses to changes in environmental conditions. Of importance are species such as the toxic dinoflagellate Alexandrium fundyense which inhabit coastal regions and are not usually dominant. The aim of this thesis was to identify physiological and behavioral diagnostics of A. fundyense from the Gulf of Maine, and use these indicators to evaluate field populations. Using a surface-specific monoclonal-antibody two methods, flow cytometry and immunomagnetic bead-separation, were developed to identify and separate A. fundyense. Flow-cytometric techniques successfully detected and separated Alexandrium from co-occurring organisms. Using immunomagnetic-separation live A. fundyense cell were separated from spiked field samples and then used to obtain accurate chlorophyll, protein and biomass estimates. Laboratory water columns, nitrogen-(N)-starved batch cultures, and N-limited, semi-continuous cultures, were used to identify indicators of different N-nutritional states. Prolonged N-stress caused dramatic changes intracellular biochemistry, specifically toxin content and composition, however behavioral modifications were not observed. The indicators, specifically toxin ratios of different derivatives, were then used to examine toxin variability in field populations. Toxin compositional changes did occur that were generally consistent with N-stress as the bloom progressed. Overall, these results suggest that these approaches could provide valuable species-specific physiological information.
Document Details
- Document Type
- Technical Report
- Publication Date
- Feb 01, 2001
- Accession Number
- ADA397388
Entities
People
- Nicole J. Poulton
Organizations
- Woods Hole Oceanographic Institution