PROBLEMS ASSOCIATED WITH COASTAL ECOSYSTEM

INTRODUCTION Coastal ecosystems are areas where land and water join to

create an environment with a distinct structure, diversity, and flow of energy.

They include salt marshes, mangroves, wetlands, estuaries, and bays and are home to many different types of plants and animals.

Coastal ecosystems are also very sensitive to changes in the environment.

The three drivers of environmental change—climate change, population growth and economic growth—result in a range of pressures on our coastal environment.

Continental shelf areas

global primary productivitymarine fish catchglobal carbonate productionglobal denitrificationglobal sedimentary denitrification

PROBLEMS OF COASTAL ECOSYSTEM

Inland waters LandVegetationBiodiversityMarine environment

Inland water

Coastal river and estuary pollution, desalination, seawater intrusion, and impacts of water abstraction (removal) on flora and fauna.

COASTAL SUBTYPES

Estuaries, Marshes, Salt Ponds, and Lagoons

It play a key role in maintaining hydrological balance ,providing habitat for birds, fish, molluscs, crustaceans.

Poor management of watersheds often leads to degradation of estuaries.

Agricultural and grazing practices that destroy natural habitats have resulted in floods and burial of the natural estuarine habitats under silt and enriched sediment.

Urbanization of watersheds interrupts natural flows of both fresh water and nutrients, and it increases pollution.

Agricultural inputs often result in excessive nutrient loading, which in turn causes large coastal areas to become eutrophied, hypoxic, or even anoxic.

Salt ponds- water become hyper saline.

Natural and artificial It provide key feeding areas for coastal birds and have

their own unique biological communities. Salt marsh subsidence has occurred due to restricted

sediment delivery from watersheds.

Mangroves

Mangroves are trees and shrubs found in intertidal zones and estuarine margins that have adapted to living in saline water, either continually or during high tides.

Found in both tropical and sub-tropical areas.

Provide protection from typhoons, flooding, soil erosion, nutrient sink, improve water quality, and allow the harvest of plant products, etc.

Mangroves are highly valued by coastal communities, which use them for shelter, securing food and fuelwood, and even as sites for agricultural production, especially rice production.

Mangroves have been converted to allow for aquaculture and for agriculture, including grazing and stall feeding of cattle and camels, etc.

Mangrove forests are also affected by removal of trees for fuelwood and construction material, changes to hydrology in both catchment basins or near shore coastal areas, excessive pollution, and rising relative sea levels.

Intertidal Habitats, Deltas, Beaches, and Dunes It provide ecosystem services such as food, shoreline stabilization,

maintenance of biodiversity and recreation.

The IPCC has identified ‘‘deltas, estuaries, and small islands’’ as the coastal systems most vulnerable to climate change and sea level rise.

Intertidal habitats provided the foundation for our knowledge of predator-prey interactions, keystone species, and other biological regulation.

The rocky intertidal habitats of temperate areas are highly productive and, in some cases, an important source of food for humans.

Food and bait collection and human trampling have substantially depleted many of the organisms in these habitats.

• Deltas are high population and human land use areas and are dynamic and highly vulnerable.

• It undergoes massive alteration due to coastal development, pollution, erosion, storms, alteration to freshwater hydrology, sand mining, groundwater use, and harvesting of organisms.

• Disruptions to the sand balance in many locations results in the total disappearance of beaches and with the loss of ecological services.

• Dune systems occur inland of the intertidal zone but are commonly found in conjunction with beaches and sandy shores.

• These habitats are often highly dynamic and mobile, changing their form in both the short and long term.

• They act as sediment reserves, stabilize coastlines, provide areas for recreation, and provide breeding and feeding sites for seabirds and other coastal species.

• Encroachment in dune areas often results in shoreline destabilization, resulting in expensive and on-going public works projects such as the building of breakwaters or seawalls and sand re-nourishment.

Coral reefs

• Coral reefs exhibit high species diversity and endemism • They are a major source of fisheries products • They support tourism industry • They contribute to the formation of beaches• They buffer land from waves and storms and prevent beach

erosion• They provide pharmaceutical compounds and opportunities • Coral reefs are at high risk from many kinds of human activity,

including coastal construction that causes loss of habitat as well as changes in coastal processes that maintain reef life.

• Destructive fishing and collecting for the marine ornamental trade; overfishing for both local consumption and export .

• Inadequate sanitation and poor control of run-off leading to eutrophication

• Dumping of debris and toxic waste

• Land use practices leading to siltation

• Oil spills

• Degradation of linked habitats such as sea grass, mangrove, and other coastal ecosystems.

• Coral reefs may be the most vulnerable to the effects of climate change. : Warming seawater triggers coral bleaching, which sometimes causes coral mortality.

• Climate change also facilitates the spread of pathogens leading to the spread of coral diseases.

Major problems of coastal ecosystem

•Eutrophication,

•Habitat modification,

•Hydrologic and hydrodynamic disruption,

•Exploitation of resources,

•Toxic effects,

•Introduction of nonindigenous species

•Global climate change and variability

•Shoreline erosion and hazardous storms, and

•Pathogens and toxins affecting human health.

EUTROPHICATION

• Moderate inputs of nutrients can have beneficial effects because they stimulate plant production, which can lead to enhanced productivity of living resources.

• Many coastal ecosystems receive excessive nutrient inputs, leading to harmful or noxious algal blooms, shifts in food chains , increased sedimentation of organic particles and depletion of dissolved oxygen.

• Eutrophication has caused oxygen depletion (hypoxia) and even elimination of oxygen (anoxia)

• Sea grass populations may decline because phytoplankton and epiphytic algae reduce the light available to sea grasses growing on the seafloor.

Nitrate concentrations have greatly increased in many U.S. rivers, resulting in increased loadings to coastal waters.

HABITAT MODIFICATION• Either natural forces or human influence pose serious threats to

coastal ecosystem

• Loss of tidal wetlands, submerged aquatic vegetation or coral reefs due to a decline in water quality or changes in sedimentation, or from changes in the hydrodynamics of coastal systems.

• Increasing plastic burden on the ocean floor can also damage coastal habitats.

• Modification of shallow water habitats, including coral and other reefs, wetlands, and sea grass beds, cause biological diversity .

HYDROLOGIC AND HYDRODYNAMIC DISRUPTION

• Changes in water circulation

• Landscape changes, channelization and damming, consumptive water uses, and diversion to other drainage basins.

• Increased freshwater flow can result because of the increase in impervious surfaces, deforestation, and channelization of flows within flood plains.

• Hydrological changes can affect not only salinity patterns and circulation within coastal systems but also the delivery of nutrients, toxicants, and sediment to the coast.

• Increase in the supply of fluvial sediments as a result of land clearing or agricultural practices.

• Geomorphological modifications of shallow coastal systems may significantly affect the hydrodynamics of the coastal regime.

• It may result from dredging of navigation channels, shoreline development and filling, shoreline protection and channelization of tidal wetlands.

• Enrichment from nonpoint sources, which causes oxygen depletion, increased turbidity, and consequent loss of submerged vegetation and associated living resources.

MANY MAJOR COASTAL ENVIRONMENTAL PROBLEMS ARE LINKED TO INLAND WATER RESOURCES

• Florida Bay - the loss of submerged aquatic vegetation and the proliferation of algal blooms cause extensive mortalities of animals.

• San Francisco Bay has been greatly altered by human activity, including the filling of most of its wetlands and the introduction of many non-indigenous species .

• Increases in the flux of nutrients, particularly nitrogen, from the Mississippi River have contributed to serious oxygen depletion over a large area of the continental shelf in the northern Gulf of Mexico.

Impacts Of Water Abstraction On Flora And Fauna

• Impacts on water bird and shorebird populations due to abstractions and extended drought were evident by 2008.

• Loss of biodiversity

• Decline of inland wetlands.

EXPLOITATION OF RESOURCES

• Fishing activities can affect ecosystems by depleting the prey of other species, reducing populations of top predators, or disrupting the physical habitat by fishing activities.

• The harvesting of sea otters for the fur trade led to a massive increase in sea urchin populations .In turn, urchins decimated juvenile kelp and so diminished the kelp forest.

• Overexploitation of filter-feeding Oysters, leading to increased turbidity and decreased survival of submerged aquatic vegetation.

TOXIC EFFECTS

• Extremely low concentrations of some organic compounds may inhibit reproductive processes in aquatic organisms by disrupting endocrine biochemistry.

• Receptor binding and enzyme induction affect development, sexual maturation, gender distributions, behaviour, and immune function.

• PAHs and PCBs can act in concert to affect marine organisms adversely.

EMERGING CONCERNS ABOUT REPRODUCTIVE PROCESS INHIBITORS

• Anthropogenic compounds, many organic, that accumulates in the waters and sediments of the coastal zone can inhibit reproductive processes of aquatic organisms.

• DDT , Tributyltin (TBT) are examples of reproductive process inhibitors.

• TBT - antifouling agent , cause female gastropods to develop male sexual organs and become effectively sterile.

INTRODUCTION OF NON INDIGENOUS SPECIES

• Consequences to coastal ecosystems include loss of biodiversity by elimination of indigenous species, alteration of trophic dynamics, degradation of habitats, loss of fisheries productivity.

• The proliferation of the zebra mussel in the Great Lakes• Dominant species of benthic invertebrates in San

Francisco Bay are nonindigenous, and the filter-feeding activities of the Chinese clam Potamocorbula amurensis have eliminated summer phytoplankton blooms in the northern portions of the bay.

GLOBAL CLIMATE CHANGE AND VARIABILITY

• Local sea level changes (from subsidence of coastal areas from freshwater withdrawal, erosion, movements of Earth's crust, and thermal expansion of seawater could add to global effects.

• Sea level rises cause significant shoreline inundation, overstepping of barrier islands, loss of intertidal wetlands, and increased salinization.

• Increased tropical storm intensity and frequency

• Changes in precipitation patterns and river flow

• Changes in seawater temperature range

• Alteration of coastal currents, which affect temperature, nutrient supply, and larval transport

• Modification of intermediate-scale weather patterns that affect winds, currents, and rainfall.

• The effects biotic communities and ecosystem productivity produced by the el Niño-southern oscillation along the southern California coast.

SHORELINE EROSION AND HAZARDOUS STORMS

• It affect coastal environmental quality.

• It also threatens coastal properties and infrastructure, such as roads, homes, and businesses.

PATHOGENS AND TOXINS AFFECTING HUMAN HEALTH

• There are two public health issues involved: (1) the induction of illness through exposures of recreational swimmers, divers, and boaters to pathogens and (2) the consumption of undercooked or raw seafood that have accumulated pathogens or toxin-bearing algae from the environmental waters.

• Norwalk virus is responsible for one-half of the epidemic occurrences of nonbacterial gastroenteritis in the United States.

Current Legislation Process

• 1990 - Coastal Wetlands Planning, Protection and Restoration Act (CWPPRA or the Breaux Act)

• April 2005 – ‘Coastal Area Restoration Bill’ and ‘Together-Immediately Defeating Erosion Act of 2005’

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