How pollutant compounds threaten coral reefs worldwide

¶ … Pollutants Compound Threats to Coral Reefs and What That Means for the Ocean and Us Humans

POLLUTANTS AND CORAL REEFS

All over the world, the existence of coral reefs in the oceans face a lot of danger caused by pollutant compounds. A lot of consideration therefore needs to be put in place to access the effects caused by these pollutants on human beings and possible remedies on the impact of the pollution to the ecosystem as a whole.

The beauty and bio diverse nature of coral reefs qualify them as a resource with a lot of worth in the ocean. Among the many uses they have include, but are not limited to, provision of shelter for marine life, human leisure, source of organisms for medicinal value, creation of sandy beaches, and acting as shoreline buffers. The use of excess carbon dioxide in the water from the air to make limestone is what millions of coral polyps (tiny animals that look like inverted jellyfish) use to create coral reefs. Coral reefs exist all over the ocean ranging from cold waters from the deepest part of the ocean to warm waters in the shallow end. Warm waters between 70-85F (21-29C) yield the greatest rate of shallow coral reef growth. The recommended depth for best coral reef growth is less than 70m (230 ft) in as much as they can also be found in depths of more than 91m (300 ft). Coral reefs do not do well in areas next to river openings that are dominated by fresh waters because they need salt water in order to thrive. Hard bottom substrate, plankton availability, existence of spices that assist in the regulation of macro algae like urchins and herbivorous fish are additional factors that contribute to the widespread of coral reefs.

Changes in temperature, fishing practices that pose a lot of damage (overfishing), pollution and more than the required amount of sediments from erosion have a diverse impact on coral. Man-made activities like the destruction of mangrove forests that take in sediments and nutrients that choke coral reefs with salt and algae blooms are just but a number of the factors that threaten coral reefs. Southeast Asia is suffering the most out of these threats.

Effects of pollutants on coral reefs

All round the world, pollution emerging from the land reduce the worth of coral reefs to the greatest extent with the Caribbean suffering at around 80% of ocean pollution coming from the land (How Pollution Affects Coral Reefs). With each passing day, pollution emerging from the land poses a lot of danger to the well-being of coral reefs due to such activities like expansion of human population into the coast, changes in the landscape due to development, and the rise in runoff emerging from the land (How Pollution Affects Coral Reefs). It is because of runoff that large amounts of sediments are swept away from the land resulting in rich nutrients being cleared from agricultural areas and sewage outflows with pollutants like petroleum products and pesticides.

Lowered amounts of oxygen and added amounts of nutrients also known as eutrophication, is caused by more than the required nutrients that lead to poor quality of water. This increases the rate at which algae grow on reefs, crowd corals and ultimately reduce the worth of the ecosystem (How Pollution Affects Coral Reefs). If sediments are deposited on reefs, their capability to feed and reproduce is messed with, same as the situation that results when the presence of pesticides is indicated. Coral diseases like white pox caused by Serratiamarcescens and sea fans caused by Aspergillussydowii have been proven to come as a result of sewage discharge and runoff that introduce pathogens into the ecosystem (How Pollution Affects Coral Reefs).

Effect of pollution on coral reef communities

Sewage pollution brings about many effects on coral reef communities, a subject that is well highlighted in this research and suggestions for future study are indicated (Pastorok and Bilyard, 1985). In the tropical marine environments, sewage pollution has been noted as a rising matter of concern with different cases of effects on coral reef communities reported. So far, very few cases of effects reported on reefs in well-flushed waters and those that take in small amounts of effluence. On the contrary, notable changes in the composition and abundance of species have been caused by high amounts of discharge of effluence into lagoons and bays that are not well-flushed (Pastorok and Bilyard, 1985). Nutrients, sediments and toxic substances are the three major components of sewage effluent that have been proven to be most dangerous to coral reef communities.

Sewage effluent may contain nutrient concentration and increase the core production of water column and benthic biomass. With increase in the production of water column, benthic filters-feeding invertebrates are on the gaining end, a situation that may lead to corals being overshadowed by other reef-building organism. Oxygen levels may also reduce due to other anthropogenic inputs of dissolved nutrients and matters of organic nature (Pastorok and Bilyard, 1985).

The short-term nature, narrow scope, poor design and unreliability of data, are the major challenges that most field studies that embarked on the investigation of the effects of the sewage pollution on coral reef on the ecosystem suffered (Pastorok and Bilyard, 1985). Wide stretch discussions prove reasonable after one sewage-stressed reef ecosystem was studied for a period of time: Kaneohe Bay, Oahu, Hawaii. It is only after the results of the short-term studies have been revised that Kaneohe Bay will be discussed.

Role of humans in the pollution

Human beings have additionally contributed too many dangerous pollutants into the ocean that could result in destruction of the delicate ecosystems of the coral reefs. Deforestation has also had indirect effects on the coral reefs like the runoff of sediments that carry with it many natural and toxic components that pose harm when they build up at river mouths leading to the ocean. Runoff that occurs in the mining and farming process is yet another major pollutant that flows into the rivers and into the ocean. Farming, particularly comes with many negative results due to the runoff from fertilizers which add nitrogen and phosphorous into the ocean. These additional nutrients enhance the growth rate of algae that cause the use up of the available oxygen in the water for aquatic creatures, affecting the biodiversity of such affected areas in addition, algae also grow to a large extent and colonizes parts of corals, preventing light from reaching such areas and limiting its level of survival.

Human activities like leaking of petroleum and other dangerous chemicals that are let loose into the ocean make coral experience a hard time in exponentially growing because of the toxic environment. In the modern cruel conditions, pollution caused by human beings have been noted to be the major source for issues involving the continued battle of survival of the Great Barrier Reefs.

The impacts of pollution to the coral reefs are significant. In case the intention to save this delicate ecosystem still exist then it is important to understand the effects of human pollution and stop it. Research shows that 22% of the world's coral reefs are threatened by land pollution (Puglise, 2007). The major type of pollution of this kind includes nutrient and chemical pollution. The pollutants in these categories include pesticides, herbicides, human derived sewage and fertilizers as well as sediments that form after land development. All these pollutants affect coral reef's ecosystem by changing it from phototropic to heterotrophic. They affect the access of light by the coral reefs yet it is needed for proper growth. In addition, the excess of nutrients especially nitrogen and phosphorus affect the great coral reef.

80% of the land adjacent to coral reefs is suitable for farming especially sugarcane as well as cattle grazing (GBR, 2007). These agricultural activities affect the coral reef. The type of fertilizers rich in nitrates and phosphorus are the main agents of pollution. These substances are found near the reef because farmers in crop and animal production prefer them. The use of nitrogen for farming and feeds may lead to the toxic substances ending up being mixed in water (Nitrogen management, 2007). The NPK group of fertilizer used by most farmers in their crops contain potassium and nitrogen and phosphorous. When the fertilizers are leached, they end up mixinh in the ocean causing more damage to coral ecosystem.

The use of agricultural pesticides also endangers coral reef health. Farmers use herbicides and pesticides to eliminate specific insects and pest damaging their crops. Unfortunately, these substances are composed of metals such as lead, arsenic and mercury that are harmful to both human beings and aquatic life (Human impact on the Great Barrier Reef). These pesticides are washed into the sea with the runoff water thus reaching the coral reefs eventually. Farming using pesticides and herbicides have negative implications on the coral reef ecosystem (Human impact of the Great Barrier Reef).

The Queensland in Australia is a perfect example of the harmful effects of runoff. This may be all the evidence you need to realize the negatives of farming on the coral reef. The runoff from the Queensland's farms have continually damaged reefs because of the runoff containing chemicals, sediments and nutrients thus causing a general decrease of coral cover. Two Australian scientists have conformed these negative effects by comparing different areas at least 400km apart (human impact on the great barrier reef). These scientists used the epidemiological technique that worked for lung cancer in 1960's. The experiment involved comparing farming effects to the harm caused on the great coral reef. This included a hypothesis on whether the quality of water had the ability to affect corals, if the runoff also had the same impact of causing coral health struggle and finally whether pollutants have any effects on coral reef (human impact on coral reefs).

The suggested relationship is between low coral reef biodiversity, pre-colonization of the reef as well as agricultural pollution. The results were that coral reefs away from agricultural activities had twice the amount of reef compared to those near farms. In addition, the decrease of coral biodiversity was also found to increase pollutants. The conclusion of this research is that use of pesticides and fertilizers for farming in this region has negative implications on the coral reef health (Human impact on the Great Barrier Reef).

Solutions

The local action/strategy for Hawaii's watershed includes natural resource management as well as other traditional land management techniques as seen in the ahupua'a. This watershed includes mountain water sources and extends the offshore to include coral reefs and coastal resources (Land-based sources of pollution). These Ahupua'a contained all the necessary resources meant to sustain Hawaiians. Through planning collaborations and public input the program was created to meet goals and objectives measuring Hawaii's LAS that focuses on demonstration projects in main Hawaii island namely the Honolua, Maui; Kawela to Kapui among others. Furthermore additional projects are currently being conducted (Land-based sources of pollution) all aiming at improving water quality and coral ecosystem function to reduce pollution. These management practices are aimed at reducing pollutant load to surface and ground water. It also improves understanding of links between land-based pollution and coral reef health that focuses on scientific research, monitoring and increasing awareness on how to prevent this pollution to meet the program's goals (Land-based sources of pollution).

Other pollution impact measuring methods have been developed. Up to date the emphasis lies on managing land use, monitoring pollutant response and NRM where different methods including multiple criteria analysis (MCA) has been used. This approach tends to focus on complex issues including environmental, social and economic factors that which is known as assessing the relative risks. Even though these analyses have been useful in reef management and investment under the rescue plan there are other techniques that work better. These new analyses prioritize pollutants in individual catchments and as such can variably incorporate both economic and social factors.

Seven water qualities were selected for an assessment of ecological risks. All these samples represented each of the pollutants affecting the ecosystem from agricultural runoff (Assessing the relative risks). The limitations were accounted for in the risk assessment through coral reef and sea grass meadow area in different assessment classes ranging from the very high to very low risks. These variables included all ecologically relevant thresholds to concentrate total suspended solids (TSS) as well as chlorophyll that comes from daily monitoring in addition to distribution of major pollutants such as TSS, inorganic nitrogen and the photo system that inhibits herbicides (PSII herbicides). This needs to be in the marine environment that can be assessed based on flood plume frequency and predicted distributions of the end of catchment loads. Also included was a spatial variable whose aim was to represent an area of GBR lagoon that is full of crown of thorn starfish in the northern side between cairns and Lizard Island. The starfish outbreaks respond to excess nutrients, which in the process lead to destruction of coral reefs as they form competition. This impact is known as the COTS initiation zone (Assessing the relative risks).

Research indicates the resilience of coral reefs showing their ability to recover from the worst situations. It is documented that the Heron Island loses all its coral reefs every decade due to cyclones but always recover showing no signs to shift on a long-term basis to another alternative (Beyond Gloom).

Human impacts are however different from natural ones like cyclones. To date, coral reefs are not being affected by a single, passing threat but several continuously occurring threats. These chronic human impacts are what cause failure of the coral reefs to recover as they become overwhelmed. As a result, most of them collapse completely (beyond gloom). Sadly, this is becoming a common phenomenon. The best evidence is accumulation of sediments over the past century on most coral reefs causing them to show little or no capacity to regain their former glory. According to Hunges, coral reefs can be salvaged by understanding reasons for degeneration into weeds without recovery, which is something that is considered the lift phase yet other corals have no problems bouncing back with resilience (Beyond Gloom).

Researchers pin point regions where reefs are returning because of reduced human pollution. One good example is the stop of sewage discharges in Kaneohe bay in Hawaii, which led to the recovery of coral reefs as well as returning sea urchin population to this part. This led to coral reefs overcoming the effects of seaweed. In the Philippines, regulation on overfishing lead to the return of parrot fish that feeds on coral reef competitor weeds (Beyond Gloom).

The recommended step is to have governments bring in researchers that will understand resilience as well as putting in relevant legislation (Beyond Gloom). Additionally, local educational programs should be started to teach locals on how to protect the region for their own benefits through working with international organizations such as CITES to protect endangered coral species (Beyond Gloom). Failure to do could result in climate changes due to acidification of the seawater as a result of excess carbon dioxide causing the waters to warm and destroy the reefs all together. The government therefore needs to confront climate change issues head on to add in the management of coral reefs by reducing all the greenhouse gas emissions.