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

Abstract

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.

Physiological responses of three species of marine pico-phytoplankton to ammonium, phosphate, iron and light limitation

“…Two prokaryotic cyanobacteria, Prochlorococcus marinus (Chisholm et al, 1988;Partensky et al, 1999) and Synechococcus spp. (Waterbury et al, 1979(Waterbury et al, , 1986Olson et al, 1990;Li, 1998;Bertilsson et al, 2003;Heldal et al, 2003) belong to the most thoroughly investigated algal species of the pico-phytoplankton community. Only a very limited number of eukaryotic pico-phytoplankton species have been investigated in detail.…”

Discrimination of Two Phycoerythrin-Pigment Types of Synechococcus and Their Seasonal Succession in the Uwa Sea

“…In the open ocean, only the high-PUB type has been found. The dominant Synechococcus in the North Atlantic and East Pacific Oceans was the high-PUB type 7,8) . Campbell and Vaulot (1993) showed that only the high-PUB type was detected at a station off Hawaii.…”

“…6c). Olson et al (1990) reported that the low-PUB type was detected at 40 out of 81 stations in coastal seas, and that 34 out of these 40 stations had both low-and high-PUB types. In the Arabian Sea, low-PUB types were more abundant at coastal stations 3) .…”

“…Dual-beam flow cytometry has been used to discriminate between types of Synechocccus based on PUB and PEB fluorescence 7,8) . In the present study, we used a single-beam flow cytometer to distinguish two types of Synechococcus in a seawater sample (Fig.…”

“…In previous studies, the high-PUB type dominated in the North Pacific Ocean 2) and the North Atlantic Ocean 7) , while the low-PUB type dominated only in coastal waters of the Arabian Sea 3) , North Atlantic Ocean and Pacific Ocean 8) where the high-PUB type was also found. To understand the ecological role of Synechococcus communities in coastal seas, evaluations of pigment-type composition are important.…”