Estuary Ecosystem Flashcards
Estuary
Located where river meets sea
No of freshwater from river mixes with salt water, and is transported by ocean
Most productive water bodies in the world
Located at the lower end of river and subjected to tidal fluctuations
Either once or twice daily washed by seawater
Characteristics of estuary
They are a semi enclosed body of water with one or more rivers or streams flowing into it
Free connection with open sea
Complete salinity range from 0-35ppt scene from head (river head) to mouth (sea end) of estuary
Has very little wave action, provides calm refuge from open sea
Provide shelter for animals
Most productive region receives more nutrients from fresh and marine water
Exhibits gradient in salinity from freshwater to Marine depending upon extent of influence of sea water
Estuary formation
Four geomorphic categories based on physical processes responsible for formation: tectonic processes, glacial processes, rising sea level and movement of sand and sand bars
Classified by geomorphological features or by water circulation patterns, bays, harbours, lagoons and inlets
Banks of estuarine channels form a favoured location for human settlements
Use estuaries for fishing and commerce, dumping civic and industrial waste
Usually biologically highly productive zones
Act as a filter for dissolved constituents in river water, precipitate in zones where river water meets seawater
Important in trapping of suspended mud and sand carried rivers lead to delta formations around estuaries
A healthy estuary
Healthy actually supports a host of plants and animals, stores and recycles nutrients, traps sediment and forms buffer between coastal catchments and Marine environment
It absorbs, traps and detoxifies pollutants, acting and natural water filter
It supports diverse habitats like mangroves, salt marshes, sea grass and mudflats, etc.
Life in estuary
Types of plants and animals adapted to brackish waters flourish in estuaries
Factors influencing growth and distribution of organisms in estuary its salinity and amount of flooding
Homes to terrestrial or land based plant & animals like wood storks, pelicans, coniferous and deciduous trees and butterflies
Homes to unique aquatic plants and animals like sea turtles, sea catfish, saltwords, eelgrass, saltgrasses, cordgrasses, sea grass, sedge and bulrush
Predators are important to estuaries because of end position in most consumer food chain
Benefits of estuary ecosystem
Water quality regulation and groundwater recharge.
Habited, breeding and nursing grounds for plants and animals
Biological productivity
Social benefits
Community values
Indigenous values
Recreational values
Knowledge and research values
Economic benefits
Commercial fishing
Ports and harbours
Navigation
Tourism
Agriculture, aquaculture and industry
Storm and erosion protection
India’s estuarine ecosystem
India has 14 major, 44 medium and 162 minor rivers that drain into sea through various estuaries
Important and distinct component of coastal landscape with highly complex ecosystems
Varying physical and chemical properties and having highly diverse flora and fauna
Major estuaries (bay of Bengal)
Locations of some major sea ports
India’s major estuaries occur on east coast
In contrast, estuaries on West coast are smaller
Problems of Indian estuarine ecosystem
Specific issues affect the estuarine environment in the country
The water flow changes in various estuaries either far in excess or much lower, like Hooghly, Narmada, Krishna, Godavari and pulicat
Modification of estuarine catchments like most Indian estuaries
Pollution through industries and combined city sewage effect most Indian estuaries
Recreation and tourism: recreational boating has affected Hooghly in West Bengal and chilika in Odisha and recreational fishing has affected chilika Lake
Navigation has affected Hooghly river
Ports and shipping, like dredging in Hooghly, shipping in Hooghly
Land use: suspension of urban and rural settlements in Hooghly, Krishna, Kaveri and pulicat
Marines, groynes, land reclamation and other structures in Hooghly and pulicat
Mining an industries in Hooghly and zuari in Goa
Agriculture (all estuaries)
Dumping of solid wastes (all Indian estuaries).
