TY - JOUR
T1 - SYNECHOCOCCUS AND ITS IMPORTANCE TO THE MICROBIAL FOODWEB OF THE NORTHWESTERN INDIAN-OCEAN
AU - BURKILL, PH
AU - OWENS, NJP
AU - MANTOURA, RFC
AU - Leakey, Ray
N1 - Copyright © 1993 Published by Elsevier Ltd.
PY - 1993
Y1 - 1993
N2 - The abundance, distribution, size, biomass, growth and grazing-induced mortality of phycoerythrin (PE) rich chrococcoid cyanobacteria were studied during September-October 1986 in the Arabian Sea, the Gulf of Oman and the monsoonal upwelling region off the South East Arabian coast. Cyanobacteria were abundant (>107 cells 1−1) through the region and particularly so (>108 cells 1−1) in oligotrophic waters where they exhbited distinct subsurface concentration maxima that were situated above, but related to the depth of the chlorophyll maxima. Cell diameter increased from 0.7 μm in surface waters to 1.2 μm at depth. Standing stocks of cyanobacteria ranged up to 50μgC 1−1, and accounted for up to 40% of the POC in oligotrophic stations indicating that Synechococcus constitutes an important trophic resource. Experimental investigations showed that cyanobacterial populations were growing fast, with specific growth rates of 0.5–1.0 day−1, while simultaneously experiencing high mortality due to microzooplankton grazing. Grazing rates varied between 0.3 and 1.2 day−1, indicating that 31–71% of the cyanobacteria were predated daily. Grazing and cyanobacterial growth were correlated, suggesting that Synechococcus production and its fate by microbial grazing activity were tightly coupled. Cyanobacteria are clearly a major component of a dynamic but well-balanced microbial foodweb present in oligotrophic regions of the northwest Indian Ocean.
AB - The abundance, distribution, size, biomass, growth and grazing-induced mortality of phycoerythrin (PE) rich chrococcoid cyanobacteria were studied during September-October 1986 in the Arabian Sea, the Gulf of Oman and the monsoonal upwelling region off the South East Arabian coast. Cyanobacteria were abundant (>107 cells 1−1) through the region and particularly so (>108 cells 1−1) in oligotrophic waters where they exhbited distinct subsurface concentration maxima that were situated above, but related to the depth of the chlorophyll maxima. Cell diameter increased from 0.7 μm in surface waters to 1.2 μm at depth. Standing stocks of cyanobacteria ranged up to 50μgC 1−1, and accounted for up to 40% of the POC in oligotrophic stations indicating that Synechococcus constitutes an important trophic resource. Experimental investigations showed that cyanobacterial populations were growing fast, with specific growth rates of 0.5–1.0 day−1, while simultaneously experiencing high mortality due to microzooplankton grazing. Grazing rates varied between 0.3 and 1.2 day−1, indicating that 31–71% of the cyanobacteria were predated daily. Grazing and cyanobacterial growth were correlated, suggesting that Synechococcus production and its fate by microbial grazing activity were tightly coupled. Cyanobacteria are clearly a major component of a dynamic but well-balanced microbial foodweb present in oligotrophic regions of the northwest Indian Ocean.
U2 - 10.1016/0967-0645(93)90057-T
DO - 10.1016/0967-0645(93)90057-T
M3 - Article
SN - 0967-0645
VL - 40
SP - 773
EP - 782
JO - Deep-Sea Research Part II - Topical Studies in Oceanography
JF - Deep-Sea Research Part II - Topical Studies in Oceanography
IS - 3
ER -