Standing-stock and potential of phytoplankton production in the Bay of Santos, Brazil

Phytoplankton primary production and the maximum photo synthetic index (Pb m) from the region of Bay of Santos were measured every two months during 1976 by simulated incubations using 14C method and incandescent lamps (737 µE.m-2 .s-140 klux) . The results obtained for production rates (maximum of 204.6 mgC.m-3.hr-1 in winter and 488.3 mgC m-3.hr-1 in summer) are among the highest recorded for tropical marine environments. A high capability of light adaptation under high temperatures was also verified. The photo synthetic indexes obtained were also very high and seems to be due to the high nutrient level of the region. The eutrophic state is supported by the high nutrient and chlorophyll-a concentrations and by the phytoplankton cells number

Multiple simultaneous detection of Harmful Algal Blooms (HABs) through a high throughput bead array technology, with potential use in phytoplankton community analysis

As an alternative to traditional, morphology-based methods, molecular techniques can provide detection of multiple species within the HAB community and, more widely, the phytoplankton community in a rapid, accurate and simultaneous qualitative analysis. These methods require detailed knowledge of the molecular diversity within taxa in order to design efficient specific primers and specific probes able to avoid cross-reaction with non-target sequences. Isolates from Florida coastal communities were sequence-analyzed and compared with the GenBank database. Almost 44% of the genotypes obtained did not match any sequence in GenBank, showing the existence of a large and still unexplored biodiversity among taxa. Based on these results and on the GenBank database, we designed 14 species-specific probes and 4 sets of specific primers. Multiple simultaneous detection was achieved with a bead array method based on the use of a flow cytometer and color-coded microspheres, which are conjugated to the developed probes. Following a parallel double PCR amplification, which employed universal primers in a singleplex reaction and a set of species-specific primers in multiplex, detection was performed in a cost effective and highly specific analysis. This multi-format assay, which required less than 4h to complete from sample collection, can be expanded according to need. Up to 100 different species can be identified simultaneously in a single sample, which allows for additional use of this method in community analyses extended to all phytoplankton species. Our initial field trials, which were based on the 14 species-specific probes, showed the co-existence and dominance of two or more species ofKarenia during toxic blooms in Florida waters

Property fields in an effluent plume of the Mississippi river

Surface property distributions were mapped in the Mississippi River plume during May and August 1993 while following surface drifters. Prevailing winds were the primary factor controlling the orientation of the plume. In May, under typical southeasterly winds, the plume turned anticyclonically towards the coast, while in August, under anomalous westerly winds, the plume turned east. Remote imagery of sea surface temperature and suspended sediments confirmed the direction of the plume. Optimally interpolated maps of surface salinity, temperature, chlorophyll a fluorescence, and transmissivity from underway sampling, and periodic nutrient samples, reveal the plume structure. In May concentrations of nitrate, silicate, and phosphate decreased linearly with increasing salinity. Chlorophyll a increased to peak concentrations of 10 μg 1 −1 in the plume, although higher pigment biomass was observed near the coast. In August nitrate and silicate concentrations decreased conservatively near the mouth of SW Pass, except where pigment biomass was enhanced in a convergent surface front. Surface nutrient concentrations in the plume also decreased with increasing salinity. The observations provide the first Lagrangian view of surface property distributions in the Mississippi River plume, and indicate that significant temporal variability exists in physical and biological properties within a day after waters are discharged from the river delta