Summary of Abstract Submission

Abstract Submission No. IO50-09-0019PresentationPoster

DYNAMICS OF MICROBIAL POPULATION IN TEMPERATURE FRONTS IN THE NORTHEASTERN ARABIAN SEA

Dr. Lidita D S Khandeparker*1, Mr. Ranjith E1, Ms. Niyati Hede1, Dr. A C Anil1

1 CSIR-National Institute of Oceanography, India

ABSTRACT :

Microbes play an important role in the food web dynamics. In oligotrophic environments, most of the organic matter is dissolved, supporting predominantly the microbial food web. High production in the northeastern Arabian Sea (NEAS) during the winter monsoon is supported by convective mixing process that brings high amount of nutrients from the base of the mixed layer to the surface, and this eventually influences the fisheries. During this season, many sea surface temperature (SST) fronts and filaments occur representing diverse biogeochemical conditions. It is expected that ocean fronts with congregated biomass may be significant sites of enhanced microbial activity but is poorly understood. Observations were carried out to investigate the microbial community in the temperature fronts in the NEAS. We were able to discriminate two types of bacterial populations (metabolically active and inactive). The front/filament was characterized by low temperature, high chlorophyll and nutrients. Abundance of metabolically active bacteria and protists was comparatively higher in the front when compared to the filament. However, the TEP abundance was more in the filament. It is known that during decline of a bloom, massive amount of organic matter such as transparent exopolysaccharides (TEP) are generated. Increase in the abundance of bacteria in the frontal region led to the decline in the TEP, indicating the role of metabolically active bacteria in TEP disintegration. These signatures are useful in determining the relative age of the process.