Seasonal dynamics of the copepod community in a tropical monsoonal estuary and the role of sex ratio in their abundance pattern.

Background: As salinity is considered the prime "ecological master factor" governing the zooplankton distribution and abundance in estuaries, a spatio-temporal interactive approach was followed to assess whether the responses of the estuarine copepod community towards the salinity are always direct with a strong positive affinity or whether there exist any complexities in their interrelationship. The study, also for the first time, addressed the role of sex ratio in governing the abundance and the population structure of copepods in the tropical monsoonal estuarine system.

Results: The ecological scenario in the Cochin estuary revealed that irrespective of the season, higher zooplankton abundance occurred in the mesohaline zone (MSZ; salinity 5-18) of the estuary, despite the pronounced spatial shift of the MSZ from the lower reaches of the estuary to upstream locations, in conjunction with the varying seasonal fluvial influx and marine water intrusion.

Plankton food web and its seasonal dynamics in a large monsoonal estuary (Cochin backwaters, India)-significance of mesohaline region.

The paper presents the ecology and dynamics of plankton food web in the Cochin backwaters (CBW), the largest monsoonal estuary along the west coast of India. The data source is a time series measurement carried out in the CBW during the Spring Intermonsoon (March-May) and the Southwest Monsoon (June-September). The plankton food web consisting of autotrophic/heterotrophic picoplankton, autotrophic/heterotrophic nanoplankton, microzooplankton, and mesozooplankton was quantified in relation to the seasonal hydrographical settings in the CBW.