Populations In Coastal Waters Research Articles

Studies on microbial population in coastal waters - V. Generic composition and physiological properties of nitrogen-scavenging bacteria isolated from marine environments.

Nitrogen-scavenging bacteria were isolated from the waters of Ise Bay, Owase Bay, Kumano Nada, Satsunan Shoto and the surrounding areas during 1983-1986.Most of the nitrogen scavengers were gram negative, asporogenous motile rods with polar flagella. All isolates were capable of assimilating NH4+ as a sole source of nitrogen. Pseudomonas (52.3%) was the most dominant bacterial genus. Pseudomonas and Vibrio comprised 78.5% of the nitrogen-scavenging bacteria isolated from coastal and oceanic waters of Japan.The optimum temperature, pH and NaCl concentration for the growth of the representative strains S10, S14 and S174 was near 30°C, pH 7.0-7.5, and 4.0-6.0% (w/v), respectively. Glucose was effective for the growth of nitrogen scavengers. Nitrogen-scavenging bacteria effectively utilized NH4Cl among nitrogenous compounds tested as a source of nitrogen.

Studies on microbial population in coastal waters. II. Distribution and generic composition of denitrifying bacteria in coastal and oceanic waters.

Distribution and generic composition of denitrifying bacteria in coastal and oceanic waters were investigated from 1980 to 1984. Denitrifying bacteria were enumerated by the M. P. N. method; their number in the surface water ranged from less than 2.0×10-1to 3.4×102 cells/ml. Almost all (98.1%) of the isolated denitrifiers (264 strains) were asporogenous, gram-negative rods with polar flagella. Denitrifying bacteria capable of forming pigments on nutrient agar or producing gas in the medium containing glucose were not isolated. About 84.8% of the isolates required NaCi for growth. Pseudomonas was the most dominant genus of denitrifying bacteria in the water column.

Effects of 1973 Floodwaters on Plankton Populations in Louisiana and Mississippi

Studies to assess the impact of floodwater diversion on plankton populations in coastal waters of Mississippi and Louisiana were conducted from 23 April 1973 through 13 July 1973. Fixed stations in Lake Pontchartrain, Lake Borgne and western Mississippi Sound were sampled once in April, twice in May and June, and once in July. Stations in Terrebonne Parish, Louisiana were visited once in May, June and July.

Rates of remineralization and assimilation of urea by fractionated plankton populations in coastal waters

Planktonic populations from three contrasting sites collected in March, May, and August, 1976, were fractionated by differential filtration into a larger fraction (LF) and smaller fraction (SF) and the kinetics of remineralization and assimilation of 14C urea in the dark by these fractions and the total populations examined. The data were plotted according to the treatment of Wright & Hobbie. Linear kinetics was generally found for total 14C turnover by the LF and SF collectively. Turnover times of the in situ urea were greatest in March when minimal phytoplankton was present and least in May at the time of the spring bloom of phytoplankton. Lowest turnover times were always found at the station in open water outside the Lough. There was no relation between turnover time and in situ urea concentrations. Maximum velocity of uptake of urea ( V) was greatest in May and least in August: the lowest values of V were always encountered in the main water body of the Lough. Comparable data for the LF followed a similar pattern. Linear kinetics of 14C urea turnover was not shown by the SF, a fraction which accounted for up to 40 % of 14C turnover. The proportion of 14C utilized by the SF increased with increasing concentration of added urea. 14C was only assimilated by the LF, the amount being 10 % or less of the total 14C turnover.