Selection for a red tide organism: physiological responses to the physical environment
The dinoflagellate Prorocentrum mariae-lebouriae has specific physiological characteristics that allow it to participate in a subsurface transport from the southern Chesapeak Bay to the northern bay, where it upwells and forms red tides. A particular growth rate dependence both on temperature and salinity restricts its year-round distribution to the high-salinty southern bay. At summer temperatures, increased tolerance to low salinities allows rapid growth in the low-salinity waters of the northern bay. Positive phototaxis is proposed to act in conjunction with downwelling convergence at a frontal region to form the initial subsurface concentration maximum or lens. Repression of positive phototaxis at a salinity interface appears to prevent the subsurface concentrations from crossing the sharp halocline, retaining the lens population in northward-flowing bottom waters. Prorocentrum increases its pigment concentration and retains its photosynthetic capacity at the extremely low light intensities encountered during the 200-km northward transport. In nutrient-poor surface waters in summer, Prorocentrum migrates at night to the higher nutrient pycnocline region. The winter-spring phasing of the streamflows in both northern and southern bays may be used to predict the degree of Prorocentrum blooming in the northern bay in summer.
- Research Organization:
- Johns Hopkins Univ., Baltimore, MD
- DOE Contract Number:
- DE-AS02-76EVO-3278; DE-AS02-76EVO-3279
- OSTI ID:
- 6503661
- Journal Information:
- Limnol. Oceanogr.; (United States), Vol. 26:2
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
54 ENVIRONMENTAL SCIENCES
ALGAE
PHYSIOLOGY
POPULATION DYNAMICS
CHESAPEAKE BAY
FORECASTING
GROWTH
MIGRATION
NUTRIENTS
PHOTOSYNTHESIS
PIGMENTS
POPULATIONS
SALINITY
SEASONAL VARIATIONS
SEAWATER
TEMPERATURE DEPENDENCE
TOLERANCE
UPWELLING
VISIBLE RADIATION
ATLANTIC OCEAN
BAYS
CHEMICAL REACTIONS
ELECTROMAGNETIC RADIATION
HYDROGEN COMPOUNDS
OXYGEN COMPOUNDS
PHOTOCHEMICAL REACTIONS
PLANTS
RADIATIONS
SEAS
SURFACE WATERS
SYNTHESIS
VARIATIONS
WATER
550100* - Behavioral Biology
520100 - Environment
Aquatic- Basic Studies- (-1989)