Environmental Science · Science

Extreme Environments


Extreme environments are crucial, as well as standard environments, to balance the life on Earth. Studying the formation, species, zonation, diversity and threats facing Coral reefs and Mangrove is necessary to establish adaptive strategies to conserve extreme environments. Mangrove forests have their own adaptive strategies which help them to survive in this hard environment. Polar Regions as extreme environments have a diversity of species that are adopted to live in these areas. They adopt to resist the impact of climate change and ozone depletion. Effective strategies have been put in the place to conserve the Polar Regions. Exploring the intertidal environment and the deep sea environment is also important to understand the threats they faced. As well as shallow water environments, climate change and pollution have a significant impact on the deep sea environment.

Coral Reefs

Corals are tiny organisms related to sea anemones. They belong to the phylum Cnidaria. They have a small can-like organ that has one open-end mouth surrounded by tentacles. The coral polyp used to catch small organisms that swim surrounding it by tentacles. It uses tentacle as a mean of food transportation and for defense. It contains small stinging cells called nematocysts. Coral reefs are formed from Calcium Carbonate layers (CaCO3) that are accumulated in warm and shallow seawater. They are formed by cooperation between the coral polyp and symbiotic dinoflagellates – zooxanthellae. They are divided into two types; soft and hard corals. Soft corals (octocorals) have no rigid skeleton. A hard coral polyp is hard and forms a protective shell.

Fringing reefs, Atoll Reefs, and Barrier reefs are three kinds of coral reefs. Fringing reefs have no lagoon associated with it, and it can be found attached to the shore. They existed in Volcano Islands and continents. Atoll reefs existed at the top of the submerged volcano island. It is a circular coral reef with the central lagoon. The barrier reef is a community of coral reefs nearby the shore that is separated by large quantities of the lagoon of open water.

There are different zonation patterns of coral reefs. It includes; back reef, reef crest, and fore-reef. Back Reef is the closest zone to the shore. It’s existed in shallow water areas. Reef crest existed between the fore-reef and back reef and away from the coast. Fore-reef has located far away the shoreline. It’s extended downwards gradually under sea levels, sometimes to great depth. Coral reefs dominate shallow water areas. Around a third of all species, are coming from shallow water coral reefs (Day, 2008). There are some animals feed on coral, such as Acanthaster planci, and Scarus species, but other use coral reefs as a place of refuge.



The Encyclopedia of Earth, Coral Reef Zonation, [online], http://www.eoearth.org/view/article/151489/ ,[Accessed, 04/10/2015].

Coral reefs have a symbiotic relationship. In the polyp, zooxanthellae algae live. These algae provide polyps by oxygen and nutrients and take CO2 and other substances from the polyp. Some fish use jellyfish’s tentacle as a trap for other fish. Fish, in return, share their meal with jellyfish. Coral reefs have exposed to several threats by human and other factors. The coral reef physical structure is not designed to resist the large-scale physical disturbance. Tropical hurricanes large waves can easily break up or overturn vast areas of living corals. Biological disturbance also can affect the diversity of coral reefs, for example, in the Pacific and Indian Oceans, the rising population of crown-of-thorns’ sea star results in the destruction of reefs. Human impact by overfishing can be considered the number one cause of the destruction of coral reefs. Fishing by using dynamite may cause damage to coral reefs and other organisms. One of the main reasons of damaging the coral reef, I think, is global warming. Rising in water temperature during El Niňo event in 1997/1998 results killing of hard coral colonies (Wilkinson, 1998).

Conservation strategies help environmentalists to conserve coral reefs. One of those strategies is Hawaii Coral Program. I can say that it’s the one of the most efficient and valuable programs for coral reef conservation. It outlines a Local Action Strategies (LAS). For me, it is very effective as it sets LAS advisory group to develop the strategy. As a result, they succeeded to establish four goals and 30 objectives (Hawaii Conservation, 2012). LAS advisory group is ranking sites in association with Coral Reef Working Group (CRWG) and key biologists. This strategy succeeded to help coral reefs to recover in Maui and Kauai. The remaining of Kaneohe Bay coral reefs has regained some color and has been recovered after the water cooled. Climate Change Action Plan 2012-2017 mainly works in Great Barrier Reefs adaptation strategy. It succeeded to manage climate change issued that related to coral reefs. One of the significant outcomes of this strategy is the Keppel Bay area coral that is now protected. I’d imagine that without this strategy, all corals in Keppel Bay would be destroyed, and it would have a great impact on the bay’s ecosystem.

Mangrove Forests

They’re trees where to grow up in tropical coasts in the muddy and soft soil. They can be considered as a connector between marine and terrestrial environments; because they existed along the coastline in the tropical and subtropical area. It’s a very productive ecosystem. The forests are the base of many of the marine food web as they can transfer energy and organic matter from land to the marine environment. Some of the commercially important species of fish and some species of coral reef use these forests as a nursery, some other species, such as shellfish, use them as a refuge. Mangrove trees have a dense root system which helps to stabilize the coastline. It also plays a crucial role in preventing erosion caused by waves and storms. Mangrove trees are the source of natural water as they work as a natural water filter. They have underwater filter feeders that clean the water of nutrients and silt.

The Red mangrove (Rhizopora mangle), the Black mangrove (Avicennia germinans), and the White mangrove (Laguncularia racemose) are the most known and comment species of mangrove forests. The red mangrove has a tangle of prop roots which helps tree to be fixed in a soft substratum. The black mangrove has a tropical tree-like trunk surrounded by a mass of pencil-like structure, called pneumatophores (Castro & Huber, 2010). The more terrestrial species of mangrove is the white mangrove.

Mangrove forests are exposed to several threats. I’d mention here some of those threats. As usual, the human has a significant impact on mangrove forests. Some of the forests are cleared to establish spaces for agriculture, human settlements, and industrial areas. Moreover, overharvesting for firewood, woodchip, pulp production, and construction wood is threatening the future of the mangrove forests. Building dams and irrigation affect the salinity level of water in the mangrove forests. Any change in the salinity of water can cause damaged of these trees. Pollution of water by fertilizers, pesticides, and toxic chemicals kill marine species that live in mangrove forests. Oil spills have a significant effect on the mangrove roots as it causes smothering of roots and suffocate the tree. The climate change that affects the sea level has the major effect on the mangrove forests. Mangrove forests need stable levels of water for long-term survival.

Adaptive Strategies with Mangrove

Mangrove adapt their leaves, roots, and their reproductive methods to survive.

Leaf Adaptations to Saline Conditions

This is one of the most efficient adaptive strategies of mangroves in a saline environment; they can close the opening of their stomata. It is a unique method to keep freshwater preserved in their leaves. Another extreme important way to prevent water loss is that they can turn their leaves away from the hot sun. I can’t imagine that the human can succeed to do so. They can excrete salt from their leaves’ glands. This is another good adaptive strategy, but I think it is not that much effective.

Root Adaptions to soft, saline, and low oxygen soils

It is one of the most valuable adaptation methods. They have the ability to survive in anaerobic soils. Some species has up-ground roots that are filled with spongy tissues with small holes to exchange oxygen with sub-ground roots. They copped to stop intake of some salts from the water. This strategy is not that much valuable. I don’t understand the mechanism of how they stop taking salts from water as they don’t have filters or sensors against salts.

Reproductive adaptation to tidal environments

Some species have adapted to produce seeds that have the ability to float. They disperse by the tide which helps to prevent crowding of young plants. On the one hand, how can they detect that seeds are crowded and how tides act as a traffic controller? I can say that this might happen spontaneously, which can’t be considered as a strategy. On the other hand, some species can retain their seeds until they become mature, then the parent tree drops it into the water. They will stay inactive until they find the soil and then put out roots. This is the most understandable and useful strategy. It explains the nature of adaptation that is required for survival.

Polar Regions

There are two Polar Regions on the earth; Antarctica and the Arctic regions. Antarctica is about 90 % of the world’s ice (Worldmark Encyclopedia of Nations, 2007), and 98% of which his covered by ice and snow (WWF, 2015), and the ice sheet contains about 30 million cubic kilometers of ice (Fact Monster,2015).  The Arctic land provides an excellent habitat for plants as the summer is warmer than that in Antarctica. There is plenty of surface water, as the water cannot drain away from permafrost. There are no large trees, but there is an enormous area of swampy plains with tundra or muskeg. Flowering plants are spreading in the Arctic land in the summer.

Around 14 million years ago, the ice sheet of Antarctica is formed (Gritzner, 2007). Needle – like frazil formed when the water begins to freeze. These crystals expelled salt and frazil became filled of freshwater. The frazil crystal floated to the surface, accumulated and bonded together forming sheets of sea ice. Calm Ocean, the congelation ice, and rough ocean, pancake, are formed depending on the climate conditions.


National Snow and Ice Data Center, Ice Formation, [online], https://nsidc.org/cryosphere/seaice/characteristics/formation.html, [Accessed, 07/10/2015].

Polar species has adopted their reproductive strategies to cope with global warming and ozone depletion. The absence of insects, limited vegetation cove, and low densities of animal that can help in pollination cause many problems to the polar species to reproduce. Plants adapt to cold weather as they extend their life cycle through several seasons due to the short growing season. The polar bear (Ursus Maritimus) reproduction depends on the migration of the female to hibernaculum. Pregnant females build a home in the thick layer of snow near to an island coast. It has lower reproductive rates than other mammals. The average interval for females is 2-3 years or sometimes four years ( Berta, L. Sumich, & M. Kovacs, 2015).There are a lot of species live in Polar Regions. In Antarctica, the flora consists of soil freshwater algae, mosses, fungi and two native species of vascular plants. Some terrestrial invertebrates, such as invertebrate protozoans, rotifers, nematodes, collembolan, and species of mite live in Polar Regions. Some of the famous species that are located in Polar Regions are; Polar bears. They have a layer of body fats and water resistance coat that protect them from cold air and water. Whales can survive in cold regions as they are warm-blooded mammals, and they have a thick layer of the bladder. Arctic Fox lives in land and away from the coast. They feed on sea birds, fish, and other marine species. Pacific Salmon began their life in freshwater streams then migrate to salty water. Brown bear also lives in the polar region.

Global warming and ozone layer depletion have great impact on the Polar Regions. The loss of ozone layer results increase in strength and frequency of storms and winds. The rising of the temperature of Antarctica help flowering plant species to become the dominant in some areas, for example, (Deschapsia Antarctica). Melting of ice and permafrost helps new plants, animals and microbial species to colonize the Polar Regions. Adelie Penguins species reduced in number and replace by Gentoo Penguins.

As a result of global warming and ozone depletion, some important actions have been taken to overcome the impact of these problems. Most of them are effective; others are still in progress. The most important and effective strategy is Kyoto Protocol. It has succeeded to reduce the Greenhouse Gases (GHSs) emissions in some countries. For example, Canada reduced their emission by 6% in 2012 compared to 1990 levels (Enzler, 2014). The UK has reduced the annual emissions by 22.5% compared to 1990 levels (Chestney, 2014). The Clean Air Act in the USA has succeeded to reduce emission in the USA. EPA partners reduced 345 million metric tons of GHS emission (Government Public Office, 2015). This is another effective strategy. I think the effectiveness is not only reducing the emission, but also, the EPA is monitoring emissions from its own energy use and fuel consumption and working to minimize GHGs emissions by 25% by 2020 (EPA, 2015). I believe they will succeed to reach this target. Another effective strategy, in my opinion, is The Montreal Protocol. It has succeeded to reduce ozone depletion substances. CFC-11 and CFC-113 emissions in the atmosphere have been declined for more than a decade (W. Fahey, D., and I. Hegglin, M., 2010). Climate Change Act helped the UK to achieve its first carbon budget. The UK succeeded to reduce 23% of carbon emission below 1990 level. This is also a very effective strategy as it requires the UK to emit no more than 3.018 MtCO2e in the 5-years’ period (Committee on Climate Change, 2013). This might be a very hard goal to be achieved, but I think the UK government has a great force to implement this goal and to enforce all participate to achieve this goal.

Intertidal Environment

The intertidal zone is the region that is completely covered by seawater at the high tide and completely uncovered at the low tides. It is occupied by marine organisms which are adopted to live in a high stressed physical environment. Intertidal environments can be divided into Rocky shores and Sandy Shores. Rocky shores are divided into the spray zone which lies above the high-tide lines and only covered by water during storms, and an intertidal zone which lies between high and law tidal extremes. The intertidal zone is divided into; the upper-tidal– infrequently covered by seawater, the middle-tidal– is regularly covered by water and uncovered by tides, and the lower-tidal– is submerged and dominated by seaweeds. Many animals live in this zone, such as Sea palms, sea-stars, and snails. Sandy Shores doesn’t have the stable foothold for sessile animals to be attached. The water slowly moves, so the shores are muddy that help fine particles to settle. Some organisms live in this area, such as bivalve mollusks, gastropod mollusks, crustaceans, echinoderms, photosynthesizing diatoms, dinoflagellates, and cyanobacteria.

The Intertidal Zones.JPG

Day, T., 2008, Ocean: Revised Edition, United States, Library of Congress Cataloging-in-Publication Data

Deep marine organisms have some adaptive strategies to survive. They include light, pressure, temperature, reproduction, and food.Adaptive Strategies to the deep sea environment

  • Light: Deep sea species have very well adapted to the absence of light. I would like to say that this is one of the most important strategies. Bioluminescence is very common in this environment that has been evolved. Dragonfish uses red light to see and snipe his prey. I believe that this adaptation is unique as most of the deep marine animals cannot see the red light. I guess that without this adaptive strategy, deep marine species would not be able to survive. I can’t imagine myself sitting in a dark room while I need to function, and survive.
  • Extreme Pressure Adaptation: Most fish species use swim bladder to maintain their buoyancy. I do not think that this strategy is effective in severe pressure. The bladder is inflated with gases, but I would ask from where they obtain gases. They might take dissolved gases in the seawater. The most acceptable strategy is that fish species relay on neutral buoyancy obtained from the dense surrounding water to fill their bladder with liquids and wax esters to add buoyancy.
  • Temperature: Imagine yourself in the kitchen surrounding with hot weather, you will be able to maintain your body temperature as your body has flexible proteins and unsaturated membranes which resist stiffening up in the cold. Deep sea animals, as same as your body, has flexible fats and protein.
  • Reproduction: Some species use bioluminescence, as well as scents, to attract the male, such as Anglerfish. This strategy can be useful in reproduction, but in my point of view I can say that here is another strategy that might be more efficient. The male can attach to the female using hook teeth, as he is smaller than the female in body size. Male share his blood vessel with the female. He provides food and sperm to the female. I strongly believe that this will help to overcome the problem of having located a new mate every breeding cycle.
  • Food: Some of deep marine fish species have large mouths that can be open very wide. This strategy provides deep water species the capability to take full advantages to take every meal available. I would like to maintain that this strategy is not available for shallow marine species. For example, anglerfish and black swallower are capable to swallow the whole prey that might be larger than themselves. They also have great extensible stomachs. The only problem is this advantage is not available for all deep sea species, so it might disturb the marine ecosystem if the food availability is disturbed.

The food availability might be disturbed by many reasons. Some of these reasons are climate change and pollution. The effect of climate change and the pollution on the deep sea environment is obvious and has a great impact. The impact of pollution can be caused by ocean mining in the deep sea as mining sites drilling for valuable minerals leaving a lot of wastes. Oil spillage can also be a very common source of the deep ocean pollution. Dumping of wastes and wet sewage sludge in the ocean may pollute the deep sea. 42 million tons of sludge dumped 2,500 m of the mid-Atlantic coast between 1986 and 1922 (Collie, and Russo, 2005). Some deep marine fish are suffering from live pathologies, tumors and other condition due to the dumping of heavy metals and industrial chemicals.

The effect of climate change can be seen in the global warming and raising of ocean temperatures. It can affect the food supply in several ways. The wind-driven changes might influence the delivery of nutrients to deep sea organisms. The changes in climate might cause heave storms and it might affect the population of some species. For example, after 1998, some species of sea cucumbers at Station M disappeared while others became more abundant. This is because of El Niño event in 1997 and 1998. Scientists say that in the North Atlantic, the seafloor-dwelling will decline by 38% and 5% globally due to the shortage of their food supply; plants and the animals live at the ocean surface (Kirby, 2014).


As we have seen, studying the formation and the environments of Coral Reefs and Mangrove forests helped to identify the effective adaptive strategies to maintain and conserve these extreme environments. Species of Polar Regions and Intertidal environments have adapted to survive in very hard conditions. Climate change and pollution impact the extreme environment. This issue needs to be looked deeply to overcome their impact.


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