Distribution Of Synechococcus Research Articles

Distribution of Synechococcus spp. determined by immunofluorescent assay

By using two polyclonal antisera against WH 7803 strain (Synechococcus sp.) and WH 5701 strain (Synechococcus bacillaris) it is possible to detect and to enumerate cells of the two cyanobacterial serogroups. The immunofluorescence technique was used to study the distribution of the two serogroups in the estuarine, coastal and upwelling waters of the Mediterranean Sea surrounding Messina. In the estuarine waters of the Alcantara River (Ionian Sea), the WH 7803 serogroup was present at a concentration in the order of 102 cells ml−1 and the WH 5701 serogroup at a concentration of 5·5 × 102 cellsml−1. In the coastal waters of Messina, where urban and industrial wastes are usuallydumped, the concentration of total phycoerythrin-Synechococcus ranged from 1·3 × 102 to 4·1 × 103 cells ml−1; the WH 7803 serogroup accounted for 50–94% of the totalpopulation in Ionian stations, whereas the WH 5701 serogroup ranged from1·4 × 101 to6·7 × 102cells ml−1. In the upwelling area (Straits of Messina) bothserogroups were found. Vertical distribution of two Synechococcus strains had anopposite trend and their concentrations were of the order of 101–102cells ml−1. Theuse of the Scan laser system allows both autofluorescent and labelled organismsto be distinguished in a preparation for optical microscopy. It also allows false-positivecells to be distinguished.

Phototrophic picoplankton community structure in three different pelagic regimes in the Arabian Sea

Cell numbers and vertical distribution of Synechococcus, eucaryotic phototrophic picoplankton and prochlorophytes as determined by epifluorescence microscopy are presented from 3 different epipelagic systems (the mesotrophic coast off Oman, the oligotrophic central Arabian Sea and the shelf edge off Pakistan) in the Arabian Sea during the inter-monsoon period 1987. The vertical distribution patterns are described in relation to the epipelagic structure of the respective study sites. Synechococcus dominated phytoplankton in the upper mixed layer and prochlorophytes at the bottom of the euphotic zone in the lower part of and below the deep chlorophyll maximum High pressure liquid chromatography analysis confirmed the presence of prochlorophytes and revealed vertical profiles of characteristic pigments of picoplankton orgamsms, chlorophyll (chl) a and b, dmnyl chl a (chl a;) and zeaxanthin. Cellular pigment concentrations of Synechococcus and prochlorophytes are presented.

Pigments, size, and distributions of Synechococcus in the North Atlantic and Pacific Oceans

Dual-beam flow cytometry was used to analyze the distribution and optical characteristics of Synechococcus in the North Atlantic and Pacific Oceans. The depth range over which Synechococcus cells were abundant was related to the depth of the nitrite maximum and the chlorophyll maximum, but was not significantly correlated with the depth of the surface isothermal layer. Dual-beam analysis of chromophore pigment types revealed that the majority of the populations were of the high-urobilin type; low-urobilin types, similar to the isolate WH7803, were found only in coastal waters where they almost always co-occurred with high-urobilin strains. Phycoerythrin fluorescence intensity per cell increased dramatically with depth in the lower euphotic zone at all stations; at some open-ocean stations, very deep cells were as much as 100 times brighter than those at the surface. The maximal fluorescence intensity per cell was about the same at the coastal and oceanic stations, and the depth of maximal fluorescence was closely related to the depth of the nitrite maximum. At most stations, fluorescence per cell was constant throughout the mixed layer, but at some open-ocean stations it decreased continuously to the surface. The latter pattern suggests that mixing rates in these areas are slow relative to the abilities of the cells to photoacclimate. A distinct diel pattern in forward-angle light scatter was observed in cells in the mixed layer over vast regions, which we hypothesize to be coupled to growth of the cells during daylight hours.