Charles L. Gallegos

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We developed an algorithm for calculating habitat suitability for seagrasses and related submerged aquatic vegetation (SAV) at coastal sites where monitoring data are available for five water quality variables that govern light availability at the leaf surface. We developed independent estimates of the minimum light required for SAV survival both as a(More)
Spectral diffuse attenuation coefficients were measured in the Rhode River and Chesapeake Bay, Maryland, on 28 occasions in 1988 and 1989. The model of Kirk was used to extract scattering and absorption coefficients from the measurements in waters considerably more turbid than those in which the model was previously applied. Estimated scattering(More)
This paper reports measurements of absorption and scattering coefficients in relation to standard water quality measurements in the St. Johns River (Florida, USA), a blackwater river in which phytoplankton chlorophyll and non-algal particulates as well as colored dissolved organic matter (CDOM) contribute substantially to the inherent optical properties of(More)
A series of three mathematical procedures is derived to discriminate the light absorption by phytoplankton, colored dissolved organic matter, and nonpigmented particulates in waters in which absorption is dominated by factors other than phytoplankton (i.e., case 2 waters). The procedures utilize normalized absorption cross-sectional spectra of the(More)
Submersed aquatic vegetation (SAV) is an important component of shallow water estuarine systems that has declined drastically in recent decades. SAV has particularly high light requirements, and losses of SAV have, in many cases, been attributed to increased light attenuation in the water column, frequently due to coastal eutrophication. The desire to(More)
In the eastern Canadian arctic the photosynthesis-irradiance curves of phytoplankton from the 50% and 1% light levels differ mainly in their susceptibility to photoinhibition. The photoinhibition parameters of deep populations and the intensity of the deep chlorophyll maximum were correlated with N2, the bulk stratification parameter of the water column.(More)
Measurements of photosynthetic pigments have been used to estimate the biomass of benthic microalgae on soft and hard substrates in a small river in the Virginia Piedmont. The irregular distribution of periphyton was partially related to substrate distribution and is explained as a result of spatial variations in the current regime in the river. High flow(More)
Using a calibrated bio-optical model we determined that the optical water quality conditions in several nitrogen-impaired embayments and in one unimpaired system were within the range of values known to support eelgrass growth. We also used the model to identify a range of light requirements for eelgrass (Zostera marina). Higher eelgrass light requirements,(More)
Grazing by microzooplankton on phytoplankton in Manukau Harbour was measured by size-fractionated dilution experiments at monthly intervals from October 1994 to October 1995. Grazing rates were always highest on the < 5 urn size fraction, the smallest size fraction measured. These rates ranged from 0.3 to 1.3 d" and were highest in November and March;(More)
In coastal ecosystems with long flushing times (weeks to months) relative to phytoplankton growth rates (hours to days), chlorophyll a (chl-a) integrates nutrient loading, making it a pivotal indicator with broad implications for ecosystem function and water-quality management. However, numerical chl-a criteria that capture the linkage between chl-a and(More)