Chrysaora cf.caliparea,one of the most abundant medusae species in India,seems to be an important predator in the coastal waters of Bay of Bengal.The ability of Chrysaora cf.caliparea to feed at maximum rate in high p...Chrysaora cf.caliparea,one of the most abundant medusae species in India,seems to be an important predator in the coastal waters of Bay of Bengal.The ability of Chrysaora cf.caliparea to feed at maximum rate in high prey concentrations implies that this jellyfish can efficiently exploit dense prey patches,at least for a short period.This study presents preliminary information regarding digestion and feeding rate upon copepods in a warm water environment.The ingestion rate of the average-sized medusae Chrysaora cf.caliparea is well balanced in nature,which in turn implies that this jellyfish is tuned for optimal utilization of available prey resources.Comparison with earlier research indicates that prey escape speed is one important factor governing which prey will be captured.A full understanding of predation mechanics awaits further investigation of both predator and prey behavior.However,because of the scarcity of long-term quantitative population data most insights have to be made indirectly.Nevertheless,low abun-dance of Chrysaora cf.caliparea in the water column during summer (May 2007) and the overall annual abundance seem not to con-siderably affect the zooplankton population,especially copepods.The present work contributes to the knowledge of prey-predator relationship of the forgotten fauna in Indian waters,which is especially crucial for understanding the process of ecological recovery of coastal water environment.展开更多
Hydrographical parameters and phytoplankton assemblages were determined along the Pondicherry, Parangipettai and Nagapattinam coastal waters, southeast coast of India. All the hydrographical parameters such as sea sur...Hydrographical parameters and phytoplankton assemblages were determined along the Pondicherry, Parangipettai and Nagapattinam coastal waters, southeast coast of India. All the hydrographical parameters such as sea surface temperature, salinity, p H, total alkalinity, dissolved oxygen and nutrients like nitrate, nitrite, inorganic phosphate and reactive silicate, chlorophyll a and phytoplankton assemblages were studied for a period of five months(May, August, September 2010, March and November 2011). Over 121 species of phytoplankton represented by 93 species of diatoms, 16 species of dinoflagellates, 9 species of blue-green algae, 2 species of greens and 1 species of silicoflagellate were recorded. High phytoplankton species diversity was found in March 2011 when salinity and nitrate concentrations were low and reactive silicate and inorganic phosphates were moderate. Species diversity was low during May 2010 when increased sea surface temperature, salinity and low nutrients availability were observed. Coscinodiscus centralis, Diatoma vulgaris and Proboscia alata were dominant, especially Coscinodiscus sp. distributed in all stations whereas Skeletonema costatum, Odontella sinensis and Ditylum brightwellii were abundant in August and September 2010. From principal component analysis and multiple regression analysis, it is evident that variables like sea surface temperature and dissolved oxygen are the most important factors influencing the seasonal pattern of phytoplankton population.展开更多
基金supported by FAPESP 2003/02433-0,2003/02432-3 and 2010/50174-7)
文摘Chrysaora cf.caliparea,one of the most abundant medusae species in India,seems to be an important predator in the coastal waters of Bay of Bengal.The ability of Chrysaora cf.caliparea to feed at maximum rate in high prey concentrations implies that this jellyfish can efficiently exploit dense prey patches,at least for a short period.This study presents preliminary information regarding digestion and feeding rate upon copepods in a warm water environment.The ingestion rate of the average-sized medusae Chrysaora cf.caliparea is well balanced in nature,which in turn implies that this jellyfish is tuned for optimal utilization of available prey resources.Comparison with earlier research indicates that prey escape speed is one important factor governing which prey will be captured.A full understanding of predation mechanics awaits further investigation of both predator and prey behavior.However,because of the scarcity of long-term quantitative population data most insights have to be made indirectly.Nevertheless,low abun-dance of Chrysaora cf.caliparea in the water column during summer (May 2007) and the overall annual abundance seem not to con-siderably affect the zooplankton population,especially copepods.The present work contributes to the knowledge of prey-predator relationship of the forgotten fauna in Indian waters,which is especially crucial for understanding the process of ecological recovery of coastal water environment.
基金the University Grants Commission,Govt.of India,New Delhi for financial support through UGCResearch Award(No.F.30-1/2014(SA-II)/RA-2014-16-SCTAM-4364 dated 05/02/2015)
文摘Hydrographical parameters and phytoplankton assemblages were determined along the Pondicherry, Parangipettai and Nagapattinam coastal waters, southeast coast of India. All the hydrographical parameters such as sea surface temperature, salinity, p H, total alkalinity, dissolved oxygen and nutrients like nitrate, nitrite, inorganic phosphate and reactive silicate, chlorophyll a and phytoplankton assemblages were studied for a period of five months(May, August, September 2010, March and November 2011). Over 121 species of phytoplankton represented by 93 species of diatoms, 16 species of dinoflagellates, 9 species of blue-green algae, 2 species of greens and 1 species of silicoflagellate were recorded. High phytoplankton species diversity was found in March 2011 when salinity and nitrate concentrations were low and reactive silicate and inorganic phosphates were moderate. Species diversity was low during May 2010 when increased sea surface temperature, salinity and low nutrients availability were observed. Coscinodiscus centralis, Diatoma vulgaris and Proboscia alata were dominant, especially Coscinodiscus sp. distributed in all stations whereas Skeletonema costatum, Odontella sinensis and Ditylum brightwellii were abundant in August and September 2010. From principal component analysis and multiple regression analysis, it is evident that variables like sea surface temperature and dissolved oxygen are the most important factors influencing the seasonal pattern of phytoplankton population.
