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This study reports on the abundance, biomass and reproductive traits of Oncaea venusta , a common pelagic copepod in tropical oceans, in a coastal area influenced by bottom intrusions of the cold and nutrient-rich South Atlantic Central Water (SACW). In addition to O. venusta abundance and biomass, we estimated egg production and weight-specific fecundity rates by applying the egg-ratio method and incubation experiments, at monthly intervals over 3 years (July 2005–June 2008), to understand potential SACW influences on reproductive patterns. Mean abundance and biomass were low, and no differences were detected with and without SACW intrusions. Mean clutch size (±SD) was 65.1 ± 28.9 eggs female−1 and egg production rates averaged 7.6 ± 12.4 and 9.3 ± 5.2 eggs female−1 day−1 (viability >80%), for the egg-ratio method and incubation experiments, respectively, corresponding to a female weight-specific fecundity from 0.03 ± 0.05 to 0.04 ± 0.06 day−1. Oncaea venusta abundance and biomass were positively correlated with temperature, but no SACW influence on the reproductive rates was recorded. The egg production rate and the female weight-specific fecundity were influenced by the chlorophyll a concentration and the sex ratio. Although egg production and female weight-specific fecundity rates had peak values during intrusion events, no immediate impact on population abundance was observed within the same time interval. [ABSTRACT FROM AUTHOR]

We studied the temporal distribution and reproductive biology of marine podonids during two consecutive years off Ubatuba, southeast coast of Brazil. Podonid specimens and their eggs and embryos were counted, measured and classified into categories. Pseudevadne tergestina was the most abundant species, and was more abundant in surface layers, in warm seasons, when the water column was stratified because of bottom intrusions of the cold and nutrient-rich South Atlantic Central Water (SACW) onto the inner shelf. Evadne spinifera had a similar temporal and vertical distribution, but with lower abundance and frequency. Pleopis schmackeri did not show a clear seasonal distribution, but preferred bottom layers. Pleopis polyphemoides and Podon intermedius occurred in low abundances, and only under SACW influence. Parthenogenetic females were dominant among all podonid species. Gamogenetic females of P. polyphemoides and P. intermedius were observed, but males of neither species occurred. This suggests that in tropical and subtropical regions, P. tergestina, E. spinifera and P. schmackeri reproduce through parthenogenesis during most of the year. [ABSTRACT FROM PUBLISHER]

Vibrio cholerae is an autochthonous marine bacterium, and its association with diverse planktonic crustaceans has been extensively investigated; however, the presence of V. cholerae on individuals of most phyla of planktonic animals is still incompletely understood. The objective of this study was to analyze the distribution of V. cholerae serogroup O1 associated with specific zooplankton taxa in an estuary and the adjacent continental shelf of the southeastern Brazilian coast. The occurrence of the bacterium was assessed in zooplankton samples, specifically on the most abundant taxa, using direct fluorescence assay (DFA) and direct viable count–direct fluorescence assay (DVC–DFA) methods. Vibrio cholerae O1 was detected in 88% of samples collected from the Santos-Bertioga estuary and in 67% of samples from the shelf. The salinity of the estuarine water ranged from 21.8 to 34.6, significantly lower than the shelf water which was 32.1–36.1. Salinity was the only environmental variable measured that displayed a significant correlation with the presence of V. cholerae (P< 0.05). Vibrio cholerae O1 was detected in chaetognaths, pluteus larvae of echinoderms and planktonic fish eggs (Engraulidae), all new sites for this bacterium. [ABSTRACT FROM AUTHOR]

Martinelli Filho, J.E.; Colwell, R.R.; Queioz, A.F.S.; Rivera, I.N.G., and Lopes, R.M., 2020. Vibrio cholerae O139 attached to zooplankton: Reservoir diversity and distribution over an estuarine-coastal gradient. In: Malvárez, G. and Navas, F. (eds.), Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No. 95, pp. 92-96. Coconut Creek (Florida), ISSN 0749-0208. Some Vibrio cholerae strains are potentially pathogenic and harmful to humans, most belong to toxigenic serogroups O1 and O139. These bacteria have many natural reservoirs and are frequently found attached to phytoplankton and zooplankton. However, the dynamics of the association between V. cholerae and zooplankton and the distribution of V. cholerae over coastal and estuarine waters and between the many biological reservoirs has proven to be of interest. Zooplankton comprise a highly diverse community and V. cholerae is known to attach mainly on crustaceans, although serogroup O1 may colonize diverse planktonic taxa including foraminiferans, polychaete larvae, and fish eggs. In order to understand the distribution of V. cholerae O139 in coastal areas and the diversity of potential zooplanktonic reservoirs, the presence of the bacterium on 43 taxa from 9 distinct phyla over an estuarine-coastal gradient in the southeast Brazilian coast was investigated during July 2005 to March 2006. Plankton was collected with a 300µm mesh net, which was washed onboard between each tow. Detection of V. cholerae O139 was assessed in whole samples and for selected taxa by DFA and DVC-DFA (Direct Fluorescence Assay and Direct Viable Count) methods. V. cholerae O139 was present in most of the estuarine samples (77%), being less common on inner shelf samples (63%) probably due to higher salinity, although a larger sampling design would be needed to test this hypothesis. Our findings suggest the occurrence of an inshore-offshore gradient for V. cholerae O139 distribution in zooplanktonic reservoir, as well as new sites for V. cholerae O139 attachment, like echinoid larvae, appendicularians, and thaliaceans. Monitoring these bacteria in cholera outbreak areas should include analyses of planktonic communities, since that may be an important natural reservoir and would ensure safety of coastal urbanized areas. [ABSTRACT FROM AUTHOR]