PLASTICS AND ITS EFFECTS ON Considering the magnitude of the ENVIRONMENT problem, the most logical sources would be somewhere along the supply chain of 1. Introduction: the plastics industry. Plastic is a toxic material that is severely affecting marine creatures and the marine ecosystems and ultimately humans. We only see the stuff that floats. But it can sink and or float depending on the environmental conditions of the ocean. Because the specific gravity of much of it is roughly that of the ocean water, it can rise in rough seas and sink during the calms. Sunlight, which has very limited penetration in the water, breaks it down into continuously smaller particles until The disposable plastic bottle it reaches molecular size. Some of the symbolizes waste and litter around the plastic debris has taken a fifty-year world. But it is not just plastic bottles voyage in violent seas since it was first and careless littering that threaten to produced. And it doesn’t appear to be turn the oceans from life sustaining to breaking down into something that is life threatening. Bottles and straws bags, even close to the natural materials of the discarded toys, product packaging and earth they once came from. There are cheap holiday decorations. Household estimates of how long this will take, but and industrial waste of a thousand it clearly takes more than fifty years. kinds. Littered, dropped, and dumped. According to a study published in 1992 Used despite safer alternatives, by the US Environmental Protection carelessly disposed, improperly Agency (EPA), plastic pellets were one managed. Not reduced, not reused and of the most abundant types of debris not recycled. Plastic in the oceans is found in US harbors of the Atlantic, entirely caused by human action and Pacific, and Gulf of Mexico. These human inaction. It has as much hurdles are the feed stock of the plastics potential to do harm as the worst industry and come in a variety of shapes climate change scenario and is having spherical, ovoid, and cylindrical — — greater immediate effects. with sizes ranging from one to five There are a number of ways that millimeters diameter. In 1992, nearly marine science, waste management, sixty billion pounds of these plastic recycling and materials experts, pellets were made annually in the biochemists and medical professionals United States and are shipped via train, might be brought together to work on truck, and ship. The most commonly the interrelated problems from a produced resins include polyethylene, number of critical angles. But currently, polypropylene, and polystyrene. there are no major collaborative efforts among these disciplines. If plastic in the and informal dump sites that are poorly ocean can be safely collected, existing located or lack proper controls. and new technologies can be used to Mega- and macro-plastics have reprocess and reuse it. Research can accumulated in the highest densities in determine the requirements, risks and the Northern Hemisphere, adjacent to potential for commercially viable urban centre’s, in enclosed seas and at operations that could turn this water convergences (fronts). Report environmental disaster into an economic reveals that, lower densities on remote opportunity for the right companies. island shores, on the continental shelf Less than 20 percent of leakage seabed and the lowest densities (but still originates from ocean-based sources like a documented presence) in the deep sea fisheries and fishing vessels. This means and Southern Ocean. The longevity of over 80 percent of ocean plastic comes plastic is estimated to be hundreds to from land-based sources; once plastic is thousands of years, but is likely to be far discarded, it is not well managed, and longer in deep sea and non-surface thus leaks into the ocean. Over half of polar environments. Plastic debris poses land-based plastic-waste leakage considerable threat by choking and originates in just five countries: China, starving wildlife, distributing non- Indonesia, the Philippines, Thailand, native and potentially harmful and Vietnam. These countries have all organisms, absorbing toxic chemicals succeeded at achieving significant and degrading to micro-plastics that growth in recent years, and they are at a may subsequently be ingested. Well- stage of economic growth in which established annual surveys on coasts consumer demand for safe and and at sea have shown that trends in disposable products is growing much mega- and macro-plastic accumulation more rapidly than local waste- rates are no longer uniformly increasing: management infrastructure. This creates rather stable, increasing and decreasing a dual problem: the scale of collection trends have all been reported. The and the retention of waste within the average size of plastic particles in the system itself. Our field research and environment seems to be decreasing, interviews with public officials have and the abundance and global also shown that these countries distribution of micro-plastic fragments acknowledge the problem and are have increased over the last few actively looking for collaborative decades. However, the environmental solutions. Of the leakage that comes consequences of such microscopic from land-based sources, we found that debris are still poorly understood. 75 percent comes from uncollected 2. What are Plastics? waste, while the remaining 25 percent Plastics are derived from leaks from within the waste- materials found in nature, such as management system itself. Post natural gas, oil, coal, minerals and collection leakage can be caused by plants. The very first plastics were made improper dumping, as well as formal by nature, rubber from a rubber tree is actually a plastic. Interest in making plastics arose in the 1800s to replace 4. Chemistry of Plastics scarce materials such as ivory and The chemistry of plastics can be tortoise shell. The first synthetic plastics complex, but the basics are were derived from cellulose, a substance straightforward. Think back to your found in plants and trees. Cellulose was high school science lessons about atoms heated with chemicals and resulted in a and molecules (groups of atoms). new material that was extremely Plastics are simply chains of like durable. The raw materials for today’s molecules linked together. These chains plastics come from many places (some are called polymers. This is why many even use salt!), but most plastics can be plastics begin with “poly,” such as made from the hydrocarbons that are polyethylene, polystyrene, and readily available in natural gas, oil and polypropylene. Polymers often are coal. made of carbon and hydrogen and sometimes oxygen, nitrogen, sulfur, 3. Types of Plastics chlorine, fluorine, phosphorous, or There are two types of silicon. plastics: thermoplastics and thermosetti The term “plastics” encompasses all ng polymers. Thermoplastics are the these various polymers. Although there plastics that do not undergo chemical are many polymers, plastics in general change in their composition when are lightweight with significant degrees heated and can be molded again and of strength. Plastics can be molded, again. Examples extruded, cast and blown into seemingly include polyethylene, polypropylene, po limitless shapes and films or foams or lystyrene and polyvinyl even drawn into fibers for textiles. Many chloride. Common thermoplastics range types of coatings, sealants and glues are from 20,000 to 500,000 amount, while actually plastics, too. thermosets are assumed to have infinite molecular weight. These chains are 4.1 Classification of Plastics based on made up of many repeating molecular Chemistry units, known as repeat units, derived Plastics are usually classified by from monomerseach polymer chain will their chemical structure of the polymer's have several thousand repeating units. backbone and side chains. Some Thermosets can melt and take shape important groups in these classifications once; after they have solidified, they are stay solid. In the thermosetting process, the acrylics, polyesters, silicones, polyur a chemical reaction occurs that is ethanes, and halogenated plastics. irreversible. The vulcanization of rubber Plastics can also be classified by the is a thermosetting process. Before chemical process used in their synthesis, heating with sulfur, the polyisoprene is such as condensation, polyaddition, and a tacky, slightly runny material, but cross-linking. after vulcanization the product is rigid and non-tacky.

4.2 Classifications based on Physical property 4.2.2. Natural vs synthetic Other classifications are based on Most plastics are produced qualities that are relevant for from petrochemicals. Motivated by the manufacturing or product design. finiteness of petrochemical reserves and Examples of such classes are the threat of global warming, bioplastics are thermoplastic and being developed. Bioplastics are made thermoset, elastomer, structural, biodeg substantially from renewable plant radable, and electrically conductive. materials such as cellulose and starch. In Plastics can also be classified by comparison to the global consumption various physical properties, such of all flexible packaging, estimated at as density, tensile strength, glass 12.3 million tonnes/year, estimates put transition temperature, and resistance to global production capacity at 327,000 various chemical products. tonnes/year for related bio-derived 4.2.1 Biodegradable plastic materials. Biodegradable plastics break 4.2.3. Crystalline vs amorphous down (degrade) upon exposure to Some plastics are sunlight (e.g., ultra-violet radiation), partially crystalline and water or dampness, bacteria, enzymes, partially amorphous in molecular struct wind abrasion, and in some instances, ure, giving them both a melting rodent, pest, or insect attack are also point (the temperature at which the included as forms attractive intermolecular forces are of biodegradation or environmental overcome) and one or more glass degradation. Some modes of transitions (temperatures above which degradation require that the plastic be the extent of localized molecular exposed at the surface, whereas other flexibility is substantially increased). modes will only be effective if certain The so-called semi-crystalline plastics conditions exist in landfill or include polyethylene, polypropylene, composting systems. Starch powder has poly (vinyl chloride), polyamides been mixed with plastic as a filler to (nylons), polyesters and some allow it to degrade more easily, but it polyurethanes. Many plastics are still does not lead to complete completely amorphous, such as breakdown of the plastic. Some polystyrene and its copolymers, poly researchers have actually genetically (methyl methacrylate), and all engineered bacteria that synthesize a thermosets. Thermoplastics which are completely biodegradable plastic, but softened by heat and can be moulded. this material, such as Biopol, is (Injection moulded, blow moulded or expensive at present.[21] Companies vacuum formed). Good examples are have made biodegradable additives to acrylic, polypropylene, polystyrene, enhance the biodegradation of plastics. polythene and PVC.

Thermosets which are formed by of deforestation because in past woods ha heat process but are then set (like were cut for usage in daily life however concrete) and cannot change shape by their usage has become limited over a reheating. Good examples are melamine period of time. (kitchen worktops), Bakelite (black 4.3.3 Efficient use of resources: saucepan handles), polyester and epoxy According to experts, Plastic resins. Composites are made by mixing usage has gone on a long way in reduce materials together to get enhanced the dependence on oil. Plasticrecycling properties. Polyester resin is mixed with has become a thriving industry in glass fibre to make GRP used for modern times with the waste being boatbuilding and fishing rods. Epoxy directed to the landfill. Plastic is also resin plus carbon fibre is stronger than used to capture the solar energy in order steel but lighter. Plastic is defined as any to generate electricity and save on the synthetic or semi-synthetic organic energy bills. Majority of people are material that can be shaped or molded suffering from the rise in the price of into any form. Chemical composition of fossil fuels, hence optimizing their plastics includes chains of carbon, usage will help to reduce the oxygen, sulfur or nitrogen. manufacturing cost and inflation. 4.3 Uses of plastic 4.3.1. Enhancement of the quality of 4.4. Effects of plastics in the life: Environment Internet, electronic devices and Although there are little to no even surgical instruments play a very empirical data on the quantity of important role in making life easier for anthropogenic debris (hereafter debris) the people. They use plastic as the entering the marine environment, medium to make the product durable estimates place it at approximately 6.4 and light weight. Continuous million tons annually (UNEP 2005), innovation has led to the refinement of such as the 2011 Japanese tsunami products made from plastic to ensure which created an estimated 1.5 million sustainable development. tons of floating debris (NOAA 2012). 4.3.2. Preservation of precious Because there is presently no way to resources: map the movement of debris in real Pipelines are being constructed time, best estimates of where debris with the help of the plastic material to accumulates come from oceanographic ensure that flow of water to different models. predicts that floating debris parts of the world. Moreover, they are accumulates in 5 main oceanic gyres also used in the construction of houses and occurs predominantly in for plumbing. Unlike iron, plastic pipes subtropical regions. Debris gathers in don’t rust when coming in contact with drift lines and convergence zones, water; therefore they are used in which are also important feeding areas multiple application right from for many oceanic species, including sea residences to industries. Usage of plastic birds, pelagic fish, and sea turtles. is instrumental in reducing the problem Plastic is the primary type of consequences of plastic pollution and debris found in marine and coastal how it affects all living things. environments and plastics are the most According to a study from Plymouth common form of debris ingested by University, plastic pollution affects at wildlife With the exponential increase in least 700 marine species, while some global plastic production over the past estimates suggest that at least 100 60 years it is likely that effects on marine million marine mammals are killed each wildlife from ingestion of plastic have year from plastic pollution. also increased. Ingestion of marine 4.5. Effects of Plastic Pollution debris affects over 170 species. Debris It seems rather obvious that this ingestion can result in death by amount of a material that isn’t meant to perforation or impaction of the break down can wreak havoc on natural gastrointestinal system and toxic environments, leading to long-term compounds in plastics may have issues for plants, animals, and people. sublethal effects on development and Some of the major long-term effects of population dynamics. The role plastic plastic pollution are: products play in the daily lives of 4.5.1. It Upsets the Food Chain people all over the world is Because it comes in sizes large interminable. We could throw statistics and small, polluting plastics even affect at you all day long (e.g. Upwards of 300 the world’s tiniest organisms such as million tons of plastic are consumed plankton. When these organisms each year), but the impact of these become poisoned due to plastic numbers border on inconceivable. ingestion, this causes problems for the For those living on the coasts, a larger animals that depend on them for mere walk on the beach can give anyone food. This can cause a whole slew of insight into how staggering our problems, each step further along the addiction to plastic has become as food chain. Plus, it means that plastic bottles, cans, bags, lids and straws (just are present in the fish that many people to name a few) are ever-present. In other eat every day. areas that insight is more poignant as 4.5.2. Groundwater Pollution the remains of animal carcasses can Water conservation is already a frequently be observed; the plastic concern in places ranging from debris that many of them ingested or California to parts of , but the became entangled in still visible long world’s water is in great danger because after their death. Sadly, an of leaking plastics and waste. If you’ve overwhelming amount of plastic ever seen a garbage dump, imagine pollution isn’t even visible to the human what happens every time it rains – then eye, with much of the pollution imagine that being in your drinking occurring out at sea or on a microscopic water. Groundwater and reservoirs are level. The short-lived use of millions of susceptible to leaking environmental tons of plastic is, quite simply, toxins. Most of the litter and pollution unsustainable and dangerous. We have affecting the world’s oceans also derives only begun to see the far-reaching from plastics. This has had terrible consequences on many marine species, Though the declining sea turtle which can lead to consequences for populations in the oceans are due to a those that eat fish and marine life for variety of factors (most all of which nutrients – including people. involve human exploitation), plastic 4.5.3. Land Pollution pollution plays a significant role. When plastic is dumped in Separate studies from 2013 suggest as landfills, it interacts with water and many as 50 percent of sea turtles are form hazardous chemicals. When these ingesting plastic at an unprecedented chemicals seep underground, they rate, and dying because of it. Another degrade the water quality. Wind carries study of the Loggerhead species found and deposits plastic from one place to that 15 percent of young turtles another, increasing the land litter. It can examined had ingested such enormous also get stuck on poles, traffic lights, quantities of plastic that their digestive trees, fences, tower etc. and animals that system was obstructed. may come in the vicinity and might Marine life can become entangled suffocate them to death. in a variety of ocean debris including 4.5.4. Air Pollution fishing nets, lines, and lures. Still, there Burning of plastic in the open air, are a number of seals and sea lions that leads to environmental pollution due to become entangled in plastic bags or the release of poisonous chemicals. plastic packing bands leading to injury The polluted air when inhaled by and death. In fact, plastic packing bands humans and animals affect their health and rubber bands continue to deeply and can cause respiratory problems. impact the Steller Sea Lion population. Some of the marine species most deeply An eight-year study in Southeast Alaska impacted by plastic pollution in Ocean. and British Columbia documented 388 4.5.5. Marine Pollution sea lions entangled in plastic debris. These plastic packing bands and rubber bands can become so embedded in the animal that it can lead to severe infection and death. Plastic pollution leads to the deaths of millions of marine bird species each year. Arguably more so Picture showing the plastic straw than other birds, the Laysan albatross blocked the nose of the sea turtles has been deeply impacted by plastic when removing it by vertenarians the debris through their hunting techniques. turtle died (Picture courtesy: S.A. When the albatross dives into the ocean Williamson) to catch fish, squid or other food they use their beak to skim the surface, Like many other marine animals, picking up plastic along the way. sea turtles mistake plastic waste for a Shockingly, an estimated 98 percent of viable food source, sometimes causing albatross studied are found having blockages in their digestive system. ingested some kind of plastic debris. Once the plastic has been ingested, it pollution impacts virtually every living causes an obstruction in the digestive organism in, or thriving off of, the tract and can puncture internal organs. oceans of our world. This is simply not Fish, along with pretty much any acceptable. The balance of our marine mammal that brings in water ecosystem is essential to our quality of through its gills, are increasingly at risk life and will ultimately depend on when to microscopic plastic debris. A study the world decides to stop turning a performed at the University of Exeter blind eye to the issue and make the UK suggested that microscopic marine necessary lifestyle changes. We all must debris could take up to six times as long remain diligent as we work to minimize for the animal to rid themselves of in our own individual consumption of comparison to ingesting the debris plastic products. So, whether you’re just orally. Of course plastic pollution beginning the journey to minimizing deeply impacts species of fish, but plastic in your life or not, there are a few unlike other animals on our list, this is key steps that never hurt to repeat. the one animal that’s also commonly References eaten by humans. A number of studies Ashmole, N.P, Ashmole, M.J. 1967. suggest that the fish humans continue to Comparative feeding ecology of consume have at one time or another sea birds of a tropical oceanic ingested plastic microfibers, including island. New Haven, Connecticut: brown trout, cisco, and perch. Peabody Museum of Natural Like other marine mammals, History, Yale University. whales often mistakes marine debris for Derraik, J. 2002. The pollution of the a potential food source. In some species, marine environment by plastic similar to that of the albatross, the debris: a review. Marine whales’ mouth is so large it Pollution Bulletin. 44:842–852. unknowingly picks up plastic debris (a Harshvardhan, K. and Jha, B, 2013. technique observed in baleen whales). Biodegradation of low-density Necropsies performed after numerous polyethylene by marine bacteria whale strandings saw an increase in the from pelagic waters, Arabian Sea, amount of plastic debris found. India. Mar Poll Bull, 77:100–106 A study also found that Plastic Breaks Down in Ocean, After All hundreds of species of cetaceans have -- And Fast. National Geographic been negatively impacted by plastic News, August 20, 2009. pollution in the past two decades. The Plastics Europe . Plastics—The Facts obstructions often puncturing and 2013: An Analysis of European tearing the stomach lining, leading to Latest Plastics Production, starvation and death.According to Demand, and Waste Data. Marine Pollution Bulletin, cetaceans are Plastics Europe; Brussels. ingesting plastic debris at a rate as high VanFraneker, J.A.2011. SNS Fulmar as 31 percent, and in turn, 22 percent of Study Group. Chemicals in those cetaceans were at an increased marine plastics and potential risk of death. It’s clear that plastic risks for a seabird like the Northern Fulmar cases SST does not represent the upper (Fulmarusglacialis. In: Carswell ocean heat content (UOHC) or the B, McElwee K, Morison S, editors. energy available to the cyclones. Fifth international marine debris Recently, Ali et al. [2013] studied the conference. Honolulu: National statistical relationship between Cyclone Oceanic and Atmospheric Intensity (CI) and SST in the tropical Administration. pp. 415–418. Indian Ocean (TIO; 30°S–30°N, 30°E– By 120°E) and concluded that satellite M. Fasuludeen, K. Prabakaran derived SST (a skin temperature) is not a and S. Ravikumar good indicator of CI. They suggested a School of Marine more accurate parameterization of SST Sciences throughout the lifetime of a cyclone, for Department of example, a parameter that also depends Oceanography and onUpper Oceanic Heat Coastal Area Studies, Content(UOHC). Alagappa Thus, the use of satellite derived SST University, Thondi campus. alone as a measure of CI needs to be reconsidered in the north Indian Ocean, as these two fields are often negatively Use of Sea Surface Temperature for correlated. Because the ocean affects the Cyclone Intensity Prediction Needs a cyclones through SST, a more accurate Relook parameterization of SST throughout the If a cyclone’s track and intensity can be lifetime of a cyclone is suggested. predicted precisely, the losses due to Replacing SST with Ocean Mean cyclones can be minimized. While Temperature (OMT), representing the efforts are under way to improve the heat energy available for cyclones in the understanding of the physics of the upper layers, is one such option. This problem of track and intensity parameter can be computed from OHC prediction, it is worthwhile to look or TCHP, which in turn can be again at the efficiency of the input computed from satellite derived SSHA. parameters presently used in models Because OMT has the same units as SST, and to look for new approaches. it can be easily assimilated into models Sea surface temperature SST ( ) is one and thus could be a good way to help such parameter that needs to be improve cyclone intensity predictions. reconsidered for cyclone studies. SST is Keywords: Cyclone Intensity (CI), Sea the only oceanographic input used in Surface Temperature (SST) most of the statistical and dynamical Reference:Ali, M. M., D. Swain, T. prediction models, though it is well Kashyap, J. P. McCreary, and P. V. known that cyclones interact with the Nagamani (2013), Relationship between upper layers of the ocean, not just with cyclone intensities and sea surface the surface. Although the upper ocean temperature in the tropical Indian drives SST depending on mixed layer Ocean, IEEE Geosci. Remote Sens. depth and upper ocean salinity, in many Lett., 10, 841–844, doi: 10.1109/ developing countries, coastal erosion is LGRS.2012.2226138 a major crisis and it potentially impacts By the coastal population and natural DEBASHIS PAUL environment. The landward Second Year M.sc displacement of the shoreline caused by Dept. of Oceanography and Coastal the forces of waves and currents is Area Studies termed as coastal erosion. It is the loss of sub aerial landmass into the sea due to Mapping of shoreline changes in- natural processes such as waves, winds between Devipattinam and Kilakkarai, and tides, or even due to human Tamilnadu, Southeast Coast of India. interference. Monitoring changes in littoral profiles to develop signatures of 1. Introduction erosion is one approach used to quantify Shoreline is the boundary between land coastal erosion (Kana 2003). Numerous and sea which is dynamic in nature. researchers viz., Selvavinayagam (2008); Beaches/ sea shores are ephemeral Chand and Acharya (2010); Kumaravel environment between land and sea with et al. (2013); Usha and Subramaniam unique and fragile ecosystems which (1994); Usha et al. (2013); Anitha and change position continuously due to Usha (2014a,b) have monitored the dynamic conditions. Shoreline change shoreline changes along may occur due to both natural and the coast based on remote sensing and man-made processes. While the effects geospatial techniques. The main of waves, currents, tides and winds are objective of this paper is to assess the primary natural factors that influence long term shoreline changes along the coast, the other aspects eroding the Tamilnadu coast, in a view to identify coastline include the sand sources and and quantify the erosion and accretion sinks, changes in relative sea level, areas. Remote sensing and GIS can be geomorphological characteristics of the used as an effective tool to identify the shore etc. Anthropogenic effects that areas that are vulnerable to coastal trigger beach erosion are construction of erosion along the coast. artificial structures, mining of beach sand, offshore dredging or building of 2. Shoreline Changes dams or rivers. Shoreline changes occur Geocoded IRS LISS II data of 1995, IRS over a wide range of time scales from LISS III 1979, LANDSAT ETM 2006 and geological to short lived extreme events SOI topographic sheets of 1969 were (Addo 2008). Shoreline assessment is a used to prepare shoreline maps on major concern in environmental 1:50,000 scale. Multi-date shoreline monitoring and integrated coastal zone maps of 1969 and1979 1995, and 2006 management (ICZM). Shoreline changes were digitized and projected using draw more attention since they are most polygonal using ARC- GIS and were important environmental indicators that overlaid using tic coordinates of the directly affect the economic study area. Overlaid maps were edited development and land management. In and labelled. Finally a temporal shoreline change map was generated in many cases these terms also refer to using intercept option of ARC-VIEW the horizontal movement of the and identified erosion and accretion shoreline associated with vertical areas along the coasts of island and changes of sea level. Recent depth offshore islands in with contour map of 1999 has been compared sufficient ground truth verification. The with bathymetry map of 1975 (Figure changes were estimated for a period of 8a&b); it reflects that the seafloor level 27 years between 1979 and 2006. decreased along the coastal and around the islands in the study area. It may be due to emerging of land or lowering of sea level (due to tectonism) and sediment deposit. In very few places particularly at river mouths and in island areas, the sea floor level has increased, which may be due to erosion caused by anthropogenic activities.

Fig.1 Shoreline Changes

3. Bathymetry Mapping Any changes in sea floor may be the result of sea-level variation or to a Fig.2 Bathymetry maps of Gulf of change in the elevation of land surface. Mannar (1975) Thanikachalam et.al. Changes in absolute water-surface (2002) levels are worldwide due to the interconnectivity of the oceans and are termed eustatic changes. Changes in the absolute level of the land are localized. They may be due to tectonic adjustments or due to adjustments caused by their distribution of weight on the land surface. As and when sedimentation or ice build-up occurs, such changes are known as isostatic. A Fig.3 Bathymetry map of rise in the sea level or down warping of coastal region (1999) Thanikachalam land would involve the opposite et.al. (2002) movements of sea and land. The average depth reduction of Synonymous with positive and negative seafloor along the coast of the study changes are the forms of sea-level area has been estimated as 0.51m over a transgression and regression, although period of 24 years. The average decrease and increase of depth around the Figure.4 Three dimensional model for islands in the study area have been Gulf of Mannar sea floor.Thanikachalam calculated as 0.56m and 0.38m et.al.( 2002) respectively. Assuming that the rate of In the shore between Tuticorin to change of depth of sea floor is uniform Vaippar River, the sea floor is sloping over a year, the rate of decrease of depth gently down to 5m depth while in is estimated as 0.021m/year along the Sippikkulam coast where the sea floor is coast and 0.023 m/year around the very steep down to 2m depth and it island, and also the rate of increase of extending up to 0.129 km from the coast. depth as 0.015 m/year around the In between 4 and 5m depths, some island. The annual sediment deposit on elevated rises and islands are noticed. Gulf of Mannar sea floor is 0.001m/year At a distance of 4.30 km (78° 12'16"E-8 (Basanta Kumar Jena 1997), so it will 49'N) from Tuticorin coast, a 3.9 m become 0.024m for a period of 24 years. elevated rise was observed. Just As found from the present study, the northeast of this riise a 6m elevated decrease of depth for the period of 24 island (78° 12'28" E-8 49'35"N) called years (1975 to 1999) is 0.51m. Out of this Van Island, which is situated 5 km away 0.51 m of decrease of depth, from Tuticorin coast. Around this island sedimentation will account for about the sea floor is sloping very gently 0.024m. The remaining 0.486 m down to 2m depth in southeast, east, reduction in depth may be due to northeast and north directions. Whereas emerging of land or lowering of sea west, southwest, and north-western level (by tectonic activities). From this, parts of the island, the sea floor slope is the rate of emerging of land or lowering very steep. On the north-eastern, eastern of sea level can be estimated as and southern sides of the island, the sea 0.02m/year. floor is covered by fringing coral reef, extending down to 2 m depth with an 4. Continental shelf morphology average distance of 1.50 km from the In Gulf of Mannar, the slope and width coast of the island. Between the depths of the continental shelf is approximately of 3m and 4m, there is another island the same as the average for the eastern called Koswari Island, which is located coast of India (Ahmad 1972). The total at 78°13'22" E-8°52'2" N, with a distance width of the shelf is around 30 km of 6.09 km from Taruvaikkulam coast. In having a slope of about 21’. The slope between 5 and 10m depths, the sea floor near the shore is about 4’. Shelf slopes moderately. From the depth of morphology (Figure 2 and 3) of the 10m to 20 m, the sea floor slopes gently, study area has been described in detail having a distance of 16.65km between by dividing the study area into four them. At a depth of 20m, the seafloor segments viz (1) Tuticorin to Vaippar falls suddenly with a very steep slope River, (2) Vaippar River to Gundar (continental slope) extending till 30m River, (3) Gundar River to Palar River depth. The width of this slope has been and (4) Palar River to Dhanushkodi calculated as 7.27 km. The total width of shelf regions. continental shelf in Tuticorin region has been calculated as 26.75 km. In the coast is plain up to 1m depth in all directions from Veppaloadi to Sippikkulam, around the island except in the north between 4m and 6m depths, elevated and northeastern directions where the islands namely KariyaShuli and slope is very steep. The shore between VilanguShuli Islands are situated at a Gundar and Palar River, the sea floor is distance of 4.77 km and 6.56 km from found at a depth of 3m, and this deep Sippikulam coast respectively. The sea extends to 1.19 km from the coast. At floor is found to be sloping gently the south of Mel Mendal coast the sea towards north, east and south from the floor slopes very steeply to 7 m depth shore of VilanguShuli Island, whereas and extends to 1.44 km from the coast. west of the the sea floor tends to slope Between the depths of 10 and 20 m the very steeply. An extensive well- sea floor slopes moderately with a developed fringing reef has been width of 7.52 km. At an average depth identified around VilanguShuli and of 20 to 30 m, there is a continental slope KariaShuli Islands extending to 3 meters with 16.56km width. In between 7 and 8 depth. m depths, the sea floor is broad and has In the shore between Vaippar and a very gentle slope. In this region Muttiapuram, the sea floor is at a depth particularly at latitude of 9°6'5"N and of 3 m., which extends to an average longitude of 78°32'10"E, an island, distance of 3.51 km from the shore. In namely Shalli Island, having 9 m the area near the mouth of Vembar the elevation from sea floor is encountered. sea floor topography is plain with a On the northern and southern sides of depth of 2 m. Between 2 m and 20 m the this island, the sea floor slopes very sea floor slopes very gently and extends steep, while on the eastern and western to a distance of 19.75 km. A sudden sides, the slope is gentle. Towards east steep slope is encountered at 20m depth, from Shalli Island another island this area is the starting point of the namely NallaTanni Island is continental slope and it extends to the encountered (78°34'29"E - 9°6'11"N). depth of 30m. The width of the slope Around this island the sea floor slopes has been calculated as 5.45 km and the very gently, particularly in the width of the continental shelf has been northeast, east and south-eastern sides calculated as 19.75 km. In the area from of the island, which extends to a depth TerkkuNarippeyur to Gundar River, the of 4 m from the shore of the island. shelf is found at a depth of 3m, Whereas northern and southwestern extending to 0.36 km south and sides of this island, the seafloor have a southeast of Narippeyur coast and 0.88 very steep slope, extending to a depth of km south of Gundar River mouth. 4 m at a distance of 0.36 m from the Between the depths of 7 and 8 km, the coast of the island. The region between sea floor is very broad and the slope is Palar River mouth and Dhanushkodi very gentle. An elevated island is found shelf, the topography has some exposed above sea level viz., irregularities. In the area opposite to UppuTanni Island situated at 6.72 km Palar River mouth, there is a gentle from Gundar River mouth. The sea floor depressed channel, having an approximate length of 4.41 km towards elevated rise and Islands are observed. south. The coast between Palar River Located at a lat-long of 78°49'10"E- mouth and Kalachimundal, the sea floor 9°9'31"N an island namely Appa Island, is found at a depth of 1 m and it extends having an elevation of 5 m from sea to a distance of 0.28 km from the shore. floor has been noticed. Around this Between these areas the sea floor island the sea floor slopes gently to 2 m gradient is very steep to a depth of 7m. depth. It extends to an average distance The width of this area is 1.60 km. After of 1.50 km. At 78°51'25"E - 9°14'2"N and reaching 7 m depth the sea floor rises 78°52'31"E - 9°14'32", two continental upto 3 m depth, this depressed channel rise have been observed having an runs to a distance of 21.27 km towards elevation of 1m from the sea floor. In northeast and south, and lies between between 4 and 5m depths, there are 78°40'4'E-9°9'15"N and 78°47'37"E- some low elevated islands (5.50 m from 9°13'8"N. The average width of this sea floor) namely Talairi, Valai and Muli channel has been measured as 0.75 km. Islands. They are located at an average After reaching 3 m depth the sea floor distance of 8.45 km from Kaplar River has a sudden fall to 10 m depth. In mouth. In this region the sea floor between the two depressions, a flat- gradient is very steep extending from 5 topped continental rise has been m depth to 10m depth and then it slopes observed. The average width of the gently upto 30 m depth. In the coast continental rise is 1.58 km and is located between and Thoniturai, 5.7 km from the shore. On this rise, there the sea floor is almost plain having a are two elevated islands rising 4m from depth of 2 to 3 m. This plain extends the sea floor and are located between 6.95 km from the coast. Near 78°41'28"E-9°9'3"N and 78°43'32"E- SenniappaDargah and Thoniturai this 9°9'4"N. These islands are called as plain is encountered at 2m depth and it Anaipar and Pilliyarmunai Islands. extends to an average distance of 2.17 Around these islands the sea floor km from the coast of SenniappaDargah slopes very gently and extensively and 0.50 km from Thoniturai coast. developed fringing corals are found Along this plain some low elevated within 2 m depth. Between 4 and 5m continental rise (79°5'19"E - 9°12'14"N) depth, at a lat-long of 78°45'8'E - and chain of islands have been 9°9'12"N, an island namely, observed. From SenniappaDargh to 6.65 Puvarasanpatti Island, having an km towards south, an island namely elevation of 4.50 m from the sea floor is Musal Island having an elevation of encountered. At a depth between 10 m 3.5m from sea floor is encountered. and 20 the sea floor slopes gently. The Around this island fringing corals have width of this continental shelf is 18.17 developed very extensively to a depth of m. In the area between Keelakkarai and 2 m, they extend 1.45 km towards north, Pudumadam, the seafloor is almost 1.75 km towards northwest, 1.69 km plain and has a depth of 3 to 4 m. This towards west and 1.42 km towards plain extends to a distance of 9.72 km south from the coast of the island. from coast. In this plain some low Around this island the sea floor slopes gently upto a depth of 2m. On the slope is steep having a width of 1.83 km. seaward side of this island, the sea floor From 10 to 30 m the sea floor slopes slope is very steep to 10m depth and to moderately. In the area between an average distance of 2 m. About 6.18 Dhanuskodi and Kundugal the sea floor km away from Marakkayarpattinam, is at a depth of 6 m and slopes there are two islands namely Manalli moderately up to 30 m depth. The width and Manalliputti Islands (79°7'26"E- of the continental shelf in this area has 9°12'23"N and 79°8'16"E - 9°12'23"N). been measured approximately as 26.25 Around these islands, the sea floor is km. encountered at 1m depth and the topography of the sea floor around this island has a moderate gradient. On the seaward side of this island, the sea floor slope is very steep, between 3 m and 6 m depths. The width of this slope is 0.73 km. At a depth of 6 to 7 m a plain having a width of 3.52 km is encountered. The sea floor slopes gently between 7 and 30 m depths. In the area between Thoniturai and canal, Figure.5 Shoreline changes-Kilakkarai the sea floor is encountered at a depth of 1 m and extends to an average distance of 1.07 km from the coast of Thoniturai and Velupilliyarkovil. In this area the sea floor slopes very gently upto 2 m depth. In between 2 and 3 m depths, there is a vast plain sea floor extending 3.80 km from north to south and 23.3 km from east to west. Along this plain there are low elevated chain of islands (79°10'28"E - 9°14'28"N and 79°14'16"E - 9°13'28") namely Pumurichan, Kovi, Figure.6 Shoreline changes and Kursadi and Shingle islands. Around shrinkage-Pampar river these islands the sea floor is encountered at a depth of 0.5m and extends to an average distance of 0.49 km towards north, 1 km towards south, 0.19 km towards east and 0.27 km towards west. In the north of these islands the sea floor slope is steep (till a depth of 1 m) whereas it is very gentle in the south (till a depth of 3 m). In between 3 m and 10 m the sea floor which is needs to be documented. In this paper we have analysed the shoreline changes rates using vector layer year wise different methods to provide consistent and reliable information in complex coastal ecosystems across different time scales. Shoreline changes along the Gulf of mannar coast over the last 27 years were studied. The high erosion was noticed on the Devipattinam region, whereas Figure.6 Shoreline changes-Valinokkam high accretion was notised along the Keelakkarai and Valinokkam. The shrinkage was noticed on the Vaikai and Pampar river mouth. Arc GIS and ENVI imagine software’s are very much useful for bathymetry mapping. Various shelf morphological features like channels, continental raise and islands, and their slopes and extents are identified. The present study suggests that in the study area sea floor has been gradually rising Figure.6 Shoreline changes- due to tectonic upliftment. Devipattinam

References Agarwal J.M. (1990), ‘Sea level variation-through bathymetric data example: Azhikkal on west coast of India’, In: Sea Level Variation and its Impact on Coastal Environment, (ed) Rajamanickam G.V, Tamil University, Thanjavur, pp.1-5.

Figure.6 Shoreline changes and Ahmad E. (1982), ‘India, coastal shrinkage-Vaikai river morphology’, The Encyclopedia of Earth Sciences, (ed) Schwartz M.L, The 5. Conclusion Encyclopedia of Beach and Coastal Shoreline mapping, inventory and Environments, Vol.15, pp.481-484. monitoring are very important information for characterization and Foot R.B. (1888), ‘Notes on management of coastal eco systems Island’, In: Madras Christian College Magazine Information System (CZIS) Pilot Project (July 1998), pp.828-840. for Rameswaram, Project Report submitted to Dept. of Ocean Jayprakash C, Maran N, Jayakumar R Development, New Delhi, 60 pp. and Kumaran K. (2002), ' Imprints of sea evel oscillation in the continental shelf De Alwis, P., H. Dissanayake and S. of Gulf of Mannar’, Newsletter, Azmy (1994). Report on water quality Geological Survey of India, Vol.XVI, aspects in the Hikkaduwa Marine pp.8-10. Sanctuary. National Aquatic Resources Agency and CRMP, Colombo. Loveson V.J. and Rajamanickam G.V. (1988a), 'Progradation as evidenced De Silva, M.W.R.N. (1984). Coral reef around as evidenced around a assessment and management submerged ancient port, Periapatnam, methodologies currently used in Tamilnadu, India’, International Journal Malaysia. In Comparing coral reef of Land.Sys.Eclo.Studies, Vol.12, pp.94- survey methods: A regional 98. Unesco/UNEP workshop, Phuket Marine Biological Centre, Thailand, Pillai C.S.G. (1972), ‘Composition of the December 1982. UNESCO Reports in coral fauna of southeastern coast of Marine Science 21: 47-56. India’, In: Regional Variation in Indian De Silva, M.W.R.N. (1985a). A strategy Ocean Coral Reefs, (ed) Stoddart C.M for the rational management of coral and Young, Symposium of the reefs. Proc. Symp. Endangered Marine Zoological Society of London, Vol. 28, Animals and Marine Parks. 1:440-447. pp.301-325. Marine Biological Association of Cochin, India. Ramasamy, S. M., 1997. “Remote sensing and creation challenging coastal De Silva, M.W.R.N. and ArjanRajasuriya engineering geological problems of (1985a). Management plans for the Tamil Nadu coast, India”.Proceedings proposed marine park. atHikkaduwa. international symposium on Paper presented at the 41st Annual engineering geology and the Sessions of the Association for environment, Greece, pp.345-348. the Advancement of Science, 9-13 December, 1985. Ramasamy S.M. (1989), ‘Morpho- tectonic evolution of east and west coast By of Indian peninsula’, In: Geological T.Kongeswaran and R.Karikalan Survey of India Special Pubilsh. Arabian Ph.D Research Scholar (Geology) Sea Seminar, No.24, pp.333-339. Department Of Oceanography and Coastal Area Studies, S. Ramachandran, R. Krishnamoorthy, Alagappa University, Thondi Campus- S. Sundaramoorthy, D. Mohan and S.P. 623409, Tamilnadu, INDIA. Karthikeyan (1994), Coastal Zone into an operational global resource Earth Resources Satellites monitoring programme. Three different There are three distinct groups of earth types of sensors have been flown in resources satellites. The first group of various combinations on the five satellites record visible and near visible missions. These are Return Beam wavelengths. The five satellites of Vidicon (RBV) camera system, the Landsat series which are the first Multispectral Scanner (MSS) system and generation earth resources satellites are the Thematic Mapper (TM). Table 4.1 a classic example of this group. The four summarizes the characteristics of IRS satellites and the more improved Landsat-1, through 5, and the sensors SPOT series of these satellites may be used on these satellites and orbital considered the second generation earth characteristics. Landsat images have resources satellites of the same group. found a large number of applications, Group two satellites carry sensors that such as, agriculture, botany, record thermal infrared wavelengths cartography, civil engineering, and include the Heat Capacity Mapping environmental monitoring, forestry, Mission satellites, namely, Explorer geography, geology, land resources series. Group three satellites are eployed analysis, landuse planning, with sensors that record micro oceanography, and water quality wavelengths. The seasat series and the analysis. ERS are examples of this group. 1. Landsat Satellite Programme National Aeronautics and Space Administration (NASA) of USA with the cooperation of the U.S. Department of Interior planned the launching of a series of Earth Resources Technology Satellites (ERTS). ERTS-1 was launched by a Thor Delta rocket on July 23, 1972 and it operated until January 6,1978. It represented the first unmanned satellite designed to acquire data about the earth resources on a systematic, repetitive, medium resolution, multispectral basis. Subsequently, NASA renamed the ERTS programme as "Landsat" programme to distinguish it from the series of meteorological and oceanographic satellites that the USA launched later. 2. SPOT Satellite Programme ERTS-1 was retrospectively named France, Sweden and Belgium joined Landsat-1. Five Landsat satellites have together and pooled up their resources been launched so far and this to develop the System Pourl' experimental programme has evolved Observation dela Terre (SPOT), an earth The IRS mission envisages the planning observation satellite programme. The and implementation of a satellite based first satellite of the series, SPOT-1 was remote sensing system for evaluating launched from Kourou Launch Range in the natural resources. The principal French Guiana on February 21,1986 components of the mission are: a three aboard an Ariance Launch vehicle axis stabilised polar sunsynchronous (AIV). This is the first earth resource satellite with multispectral sensors, a satellite system to include a linear array ground based data reception, recording sensor employing the push broom and processing systems for the scanning technique. This enables side- multispectral data, ground systems for to-side oft-nadir viewing capabilities the in-orbit satellite control including and affords a full scene stereoscopic the tracking network with the associated imaging from two different viewing supporting systems, and hardware and points of the same area. The high software elements for the generation of resolution data obtained from SPOT user oriented data products, data sensors, namely, Thematic Mapper (TM) analysisand archival. The principal aim and High Resolution Visible (HRV), of the IRS mission is to use the satellite have been extensively used for urban data in conjunction with planning, urban growth assessment, supplementary/complementary transportation planning, besides the information from other sources for conventional applications related to survey and management of natural natural resources. resources in important areas, such as, agriculture, geology and hydrology in association with the user agencies. IR$ series of satellites are IRS lA, IRS IB, IRS IC, IRS ID and IRS P4 apart from other satellites which were launched by the Government of India. The orbital and sensor characteristics of IRS IA and IB are the same and IRS IC and IRS ID have almost similar characteristics. IRS P4 is an oceanographic satellite, and this will be discussed in the next section. IRS has application potential in a wide range of disciplines such as management of agricultural resources, inventory of forest resources, geological mapping, estimation of water resources, study of coastal hydrodynamics, and water quality surveying. The sensor payload system consists of two push 3 Indian Remote Sensing Satellites broom cameras (LiSS-II) of 36.25 m (IRS) resolution and one camera .(LlSS-I) of 72.5 m resolution employing linear is to provide optimum satellite Charge Coupled Device (CCD) arrays as operation and a mission control centre detectors. Each camera system images in for mission management, spacecraft four spectral bands in the visible and operations and scheduling. The three near IR region. The camera system sensors on board IRS-1 D and IRS-1 C consists of collecting optics, imaging are described in the following detectors, inflight calibration paragraph. The panchromatic camera equipment, and processing devices. The provides data with a spatial resolution orbital characteristics of the IRS-1A, 1 B of 5.2-5.8 m (at nadir) and a ground satellites and the sensor capabilities are swath between 63 Km -70 Km (at nadir). given in Table 4.3. As IRS-1 D satellite is It operates in the 0.50 - 0.75 microns the latest satellite of the series and hence spectral band. This camera can be the system overview of IRS - 1 D is steered upto ± 26 deg. storable upto provided. The IRS-1 D is a three-axes ±398 Km across the track from nadir, body stabilized satellite, similar to IRS-1 which in turn increases the revisit C. Since IRS-1 C and 1 D are similar in capability to 3 days for most part of the orbital characteristics and sensor cycle and 7 days in some extreme cases. capabilities, the details of IRS-1 D are The LlSS-1i1 sensor provides discussed as it is a very recent satellite. multispectral data collected in four It will have an operational life of three bands of the visible, near infra-red years in a near polar sunsynchronous (V,NIR) and short wave infra-red orbit at a mean altitude of 780 Km. The (SWIR) regions. While the spatial payload consists of three sensors, resolution and swath in the case of namely, Panchromatic camera (PAN), visible (two bands) and NIR (one band) linear imaging and self-scanning sensor regions are between 21.2 m to 23.5 m (LiSS-III) and wide Field sensor (WiFs). and 127 Km-141 Km.respectively, they The satellite is equipped with an On- are between 63.6 m to 70.5 m and 133 Board Tape Recorder (OBTR) capable of Km to 148 Km for the data collected in recording limited amount of specified SWIR region. (Table 4.5). Plate 3 shows sensor data. Operation of each of the IRS-1D LlSS III FCC image (band 2, 3, 4) sensors can be programmed. The and corresponding black and white payload operation sequence for the images of band 2, band 3, and band 4 of whole day can be loaded daily on to the path 108, row 56 showing Culcutta and on-board command memory when the surrounding areas. The Wide Field satellite is within the visibility range. Sensor (WiFS) sensor collects data in The ground segment consists of a two spectral bands and has a ground Telemetry Tracking and Command swath between 728 Km to 812 Km with (TTC) segment comprising a TTC a spatial resolution of 169 m to 188 m. network, and an Image segment comprising data acquisition, data processing and product generation system along with data dissemination centre. The over view of IRS-1 D mission prediction, and monitoring industrial thermal pollution.

By Mr.T.Kongeswaran Ph.D Research Scholar (Geology) Department Of Oceanography and

4. AEM Satellites Coastal Area Studies, The (Heat capacity Mapping Mission) Alagappa University, Thondi Campus- HCMM satellite is the first of a small 623409, Tamilnadu, INDIA. and relatively inexpensive series of NASA's Applications Explorer Mission (AEM) satellites. Launched in April 1978, it lasted till September 1980. Table 4.7 summaries the details of AEM satellite and HCM sensor characteristics. The orbits of the satellite are arranged to ensure that images of each scene are obtained during the periods of maximum and minimum surface temperature for the determination of thermal inertia. The data from HCMM are intended primarily for conversion to thermal inertia maps for geological mapping. However, the images have found wider applications, such as, vegetation mapping, vegetation stress detection, microclimatology, soil moisture mapping, snowmelt