Eutrophication induced changes in benthic community structure of a flow-restricted tropical estuary (Cochin backwaters), India.
The influence of anthropogenic loading on the distribution of soft bottom benthic organisms of a tropical estuary (Cochin backwaters) was examined. The industrial activities were found to be high in the northern and central part of the estuary, where dissolved inorganic nitrogen (DIN > 210 μM) and phosphorus (DIP > 6.5 μM) have caused high abundance of chlorophyll a (up to 73 mg m(-3)) and accumulation of organic carbon in sediments (up to 5%). Principal component analysis distinguished three zones in the estuary. The central zone (Z1) was characterized by organic enrichment, low species diversity, and increased number of pollution tolerant species. Long-term deterioration of the estuary is indicated by an increase in the nutrients and chlorophyll a levels by sixfold during the last few decades. Flow restrictions in the lower estuary have lead to a fourfold increase in sediment organic carbon over the period of three decades. The reduced benthic diversity followed by an invasion of opportunistic polychaetes (Capitella capitata), are indicative of a stress in the estuary.
Martin
G D
GD
National Institute of Oceanography (CSIR), Regional Center, P.B.No 1913, Cochin, 682018, India. martinnio@gmail.com
Nisha
P A
PA
Balachandran
K K
KK
Madhu
N V
NV
Nair
M
M
Shaiju
P
P
Joseph
T
T
Srinivas
K
K
Gupta
G V M
GV
D000818:Animals; D002244:Carbon / Q000378:metabolism; D002734:Chlorophyll / Q000378:metabolism; D000077194:Chlorophyll A; D004784:Environmental Monitoring / Q000379:methods*; D005068:Eutrophication / Q000502:physiology*; D007194:India; D007448:Invertebrates / Q000254:growth & development* / Q000378:metabolism; D025341:Principal Component Analysis
D002734:Chlorophyll; D002244:Carbon; D000077194:Chlorophyll A