Pollution in Bays and Estuaries (PDF)

Summary

This document discusses pollution in bays and estuaries. It describes the differences between bays and estuaries and highlights the importance of estuaries in maintaining biodiversity. The document covers the various ways pollution harms these ecosystems, from natural erosion and urban contaminants to invasive species and ocean mining. Its focus is on the effects of pollution on marine life and potential solutions, making it valuable to anyone studying environmental science and marine ecosystems.

Full Transcript

***POLLUTION IN BAYS AND ESTUARIES,*** ***How do bays differ from estuaries?*** An **estuary** is defined as a partly enclosed body of water along the coast where one or more streams or rivers enter and mix freshwater with seawater. A **bay** is defined as a body of water partially enclosed by la...

***POLLUTION IN BAYS AND ESTUARIES,*** ***How do bays differ from estuaries?*** An **estuary** is defined as a partly enclosed body of water along the coast where one or more streams or rivers enter and mix freshwater with seawater. A **bay** is defined as a body of water partially enclosed by land that is directly open, or connected, to the ocean. In Texas, many **bays** are also **estuaries**. ![](media/image2.jpeg) ***Estuaries, such as our coastal bays, form the transition between the land and the sea; creating a unique and diverse ecosystem.*** ------------------------------------------------------------------------------------------------------------------------------------- **Importance of estuaries** 1. Estuaries are partially enclosed bodies of water, where fresh water from rivers and streams mixes with salt water from the ocean. Estuaries, such as our coastal bays, form the transition between the land and the sea; creating a unique and diverse ecosystem. 2. Estuaries are among the most productive ecosystems in the world, along with coral reefs and tropical rain forests. 3. They [filter] water brought in by the surrounding watershed, which is the area of land that drains into a particular body of water. This filtered water brings nutrients from the watershed, but also many of the pollutants. 4. Estuaries and their surrounding wetlands filter out pollutants such herbicides, pesticides, heavy metals and excess nutrients and sediments. For this reason, estuaries comprise one of the most fertile ecosystems, but also have the potential be the most polluted. 5. Thousands of species of wildlife rely on estuaries for their survival. 6. Many commercially important species of fish, such as herring, menhaden, sea bass and striped bass, spend a portion of their life cycle in estuaries. 7. Estuaries function as important spawning ground for these species and provide protection for juvenile fishes. 8. Migratory waterfowl utilize estuaries as areas to rest and feed on their seasonal journeys. Crustaceans and shellfish, such as the infamous blue crab and Eastern oyster, also make estuaries their home, residing in underwater grasses. 9. Wetlands and estuaries also act as buffer zones (minimizing effect). They absorb floodwaters and protect against storm surges by acting as sponges and absorbing excess water. Wetlands and estuarine plants stabilize shorelines, which minimize erosion caused by waves, wind and ice. 10. Additionally, these wetlands sequester or store large amounts of carbon in their soils. Carbon sequestration is beneficial as it helps mitigate the effects of climate change. a. natural erosion. a large portion of this land loss is due to development. Sediment slugs. When it rains, soil is eroded from the catchment, washes into streams and rivers, and makes its way down to the coast, where it is dispersed and ultimately deposited. If the conditions are right, then some part of that load of eroded sediment may deposit in a noticeably thick "slug" in some parts of the estuary. If the slug is thick enough and covers a wide-enough area, then estuarine plants and animals unlucky enough to be under the slug can be smothered and killed. b. Since wetlands and estuaries act as a filter to pollution and excess nutrients, these contaminants can often build up and cause what is known as eutrophication. c. Eutrophication is caused by excess nutrients and may contribute to excessive growth of algae, depleting the water of oxygen when algae die. d. Urban contaminants.When it rains, zinc is leached from galvanised iron roofs (by design), gets washed into stormwater drains, and for the most part attaches itself to fine sediment particles that are also travelling in the runoff. The sediment with its attached zinc load makes its way down to the coast where it is dispersed and, ultimately, deposited. If the zinc in the deposited sediments reaches a certain high concentration, then it can be toxic to the biota. e. This lack of oxygen, known as anoxia, is problematic for wildlife in the estuaries and can result in significant mortality among fish populations. f. Invasive species Some nuisance and pest species invaded; others were invited. An example of an invited species is cordgrass (genus *Spartina*),which was planted to prevent shoreline erosion and as part of reclamation schemes to extend pastures. The Department of Conservation have tried to eradicate *Spartina* by spraying with Gallantto no avail g. Faecal contamination \'Flood flushing of bugs in agricultural streams\', pastoral agricultural streams are chronically contaminated by livestock faeces. These may be washed by rainfall from pastures into streams,,danger being faeces of all warm-blooded animals -- which includes humans-- can contain disease causing micro-organisms (or "pathogens"). NB: you will notice that most problems in the estuary start "when it rains". Why? Remember, estuaries are at the bottom of the freshwater drainage network, which means that "what ails our estuaries" often comes from the land, carried down streams and rivers by rainwater **OFFSHORE OIL AND GAS DEVELOPMENT, AND DELIBERATE WASTE DISPOSAL IN THE SEAS.** Image result for offshore oil and gas development **About Offshore Oil & Gas Industry** Ocean dumping refers deliberate dumping of materials like garbage, construction and demolition debris, sewage sludge, dredge material, and waste chemicals in the ocean. Materials in the ocean are often dumped on the continental shelf. In some cases, ocean dumping is regulated and controlled, while some dumping occurs haphazardly by ships and tankers at sea, or illegally within coastal waters. The legal definition of ocean dumping refers to the dumping of garbage, sewage, waste chemicals, and construction debris into the ocean. There are many cases where ocean dumping is controlled and regulated. However, there are hazardous materials being dumped into the sea by tankers and ships. They are also being illegally dumped in coastal waters. **Causes of Marine Pollution** ------------------------------ ### 1. Ocean Dumping Among all sorts of activities that pollute the ocean, dumping of garbage and other waste materials stands first in the list. Dumping involves depositing all the waste materials from factories and industries, tankers and ships and sewerage waste materials into the oceans and seas. Some of the materials emitted by the industrial wastes and sewage wastes contain materials like mercury, cryolite and DDT. Certain industrial wastage also includes radioactive materials. Even small amounts of these substances tend to have negative effects. The scale and the magnitude of the ocean dumping are not just vast but are so huge, that our entire civilisation could be wiped out with the intensity of careless dumping. The discharge of ballast water also causes the problem by way of ocean waste. Ballast water tends to proliferate and transfer organisms that debilitate the growth of naturally occurring fishes in a particular oceanic area. ### **2. Land Runoff** According to researchers, many pollutants, almost eighty percent pollution, are released into the marine environment far upstream from coastlines. The non-point pollution, which is a result of land runoff brings many wastage materials such as the debris of cars and boats into the sea every day. Moreover, rivers during floods pick up harmful contaminants including fertilizers, petroleum, and pesticides, among others. Studies have suggested that the presence of fertilizers in the ocean will result in the sudden explosions of marine algae, which can disrupt ocean ecosystems, and also the creation of dead zones in the waters. ### **3. Oil Spills** [Spilling of oil](https://www.marineinsight.com/guidelines/fighting-oil-spill-on-ship/) from tankers and offshore rigs in the oceanic area is also another example of sea pollution. Several of such oil spills from tanker ships after accidents, including Deepwater Horizon, Gulf War oil spill and Atlantic Empress*, *have shown us the extent of the damages the spills can do to the ecosystems. Spilling of oil can happen inadvertently where small doses of oil are leaked into the oceans by the tanker ships or in a massive scale where gallons and gallons of oil are leaked into the water surface of the ocean after the collision of vessels or capsizing. The pollution through oil spills can have serious consequences for society, both economically and environmentally. Importantly, the main victims of oil spills are birds and mammals. [The Gulf of Mexico oil spill](https://www.marineinsight.com/environment/the-gulf-of-mexico-oil-spill-the-complete-story/) has caused problems to birds among the other marine creatures whose wings had gotten covered by the slick, causing them to die a slow and painful death. ### **4. Littering** Beaches covered with plastic wastes are not a rare scene in these days. Besides the large chunk of industrial wastes, the dumping of plastic is another biggest source of pollution as it slowly leads to adverse effects. Materials like plastic are non-degradable which means they will not be absorbed and recycled. When oceanic creatures and even birds consume plastic inadvertently, they choke on it which causes a steady decline in their population. Activists say who suffer from the plastic debris are dolphins, sharks, turtles, crabs, and sea birds, among others. The Pacific Ocean Garbage Patch is a very good example of plastic being hazardous and Islands like Henderson have transformed from the beautiful lands to Plastic Junkyards. ### **5. Ocean Mining** Mining under the ocean for silver, gold, copper, cobalt, etc. is another source of ocean pollution. Mines, where ores are drilled thousands of meters down, dispose of their wastes in the ocean, creating disastrous impacts in the marine life on the seabed. Researchers, with limited scientific evidence, suggest that such activities help increase the toxicity, which will eventually put ecosystem in the area under threat. ### **6. Noise Pollution** Besides these reasons, the aquatic life in the sea is also disturbed by several other factors. Recent studies have proved that the increasing noise pollution in the sea also creating threats to the marine life. In addition to the increased traffic, the loud sounds from sonar devices and oil rigs also making the situation worse. According to researchers, the noise pollution will disrupt the migration and reproduction patterns of mammals like whales and dolphins. **Effects of Ocean Dumping** ---------------------------- Oil spills are dangerous for marine life and can affect coral reefs that thrive in the ocean. In fact they can greatly affect the life cycle. The gills of fish can be clogged by spilled oil which can block off respiration. If sunlight is blocked, marine plants will die because it affects photosynthesis and its process. These toxins not only affect the marine life, but they affect humans as well. For example, let's say the fish are contaminated, if someone were to catch a fish and eat it, they could get food poisoning. If garbage is dumped into the ocean, the oxygen in the water could be depleted. This results in poor health for marine life due to lack of oxygen. Animals such as seals, dolphins, penguins, sharks, whales, and herring could all die. Bottles and other plastics including bags can suffocate or choke sea creatures. Thinking they are food, they may eat them. Plastic items are one of the major causes of death among turtles. They think plastic bags look like jellyfish and try to eat them. The effects of ocean dumping are due to our carelessness. Roughly two thirds of the world's marine lives have been threatened with chemicals we throw down the drain every day such as house hold cleaners. It may do you good to remember that marine life is a part of our food chain. Not only do we eat fish and other marine life, but so do other animals. Underwater creatures are a main food source for other fish and bears. There's a lot we can do to save our oceans. The best place to start is to keep them clean and not throw anything into them. It's also a good idea to keep the beaches clean. Garbage on the beach can easily end up in the water. Another thing we can do is to stop pouring chemicals down the drain such as paint or oil. Stop using toxic household products and don't overwater our lawns, in other words, conserve water. Now that you know the cause and effects of ocean dumping, you'll be able to understand that it's just something you shouldn't do. You never know how much water is worth, until you have none. It's best to remember the causes, consider the animals and always keep them in the back of your mind. If we work together we can stop the effects of ocean dumping for good.

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