2020-10-10
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Environmental problems concerning marine ecosystems include unsustainable exploitation of marine resources (for example overfishing of certain species), water pollution, and building оn coastal areas.
Human activity impacts upon marine ecosystems just as it does on land, with the areas nearest the coast being most affected. For instance, the coral reefs are among the world’s most threatened biomes. They are affected by a range of factors, including destructive fishing practices, pollution, and sewage. Meanwhile, global warming is already causing bleaching of coral reefs. Increased temperatures destroy the symbiotic relationship between the coral and the algae that live there. According to research from the United Nations, one third of coral reefs around the world are destroyed already, 60% are damaged and will likely be dead by 2030. Mangrove swamps are similarly at risk.
Estuaries and shore areas are also at risk from pollution, which can cause eutrophication by raising nutrient levels in the water. Eutrophication encourages the growth of decomposers that consume available oxygen in the water. As oxygen levels fall, fish and other organisms begin to die off. Eutrophication also causes an overgrowth of algae in the water, often visible as a red, yellow, or green scum on the surface and a visible sign of a threatened ecosystem. These dead zones are found
in many areas around the world, such as the Mediterranean and the East Coast of the United States. The deep ocean has also been used as a dump for low radioactive waste, although this was banned in 1993. There have also been discussions on burying medium and high-level radioactive waste from nuclear power stations. If land alternatives prove too risky, these options may be put into practice, but no one knows what the longterm impact might be upon marine ecosystems, however secure the waste was made.
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Humans do not just put things into the seas and oceans. They take things out as well. Fishing is a traditional activity, with fish being an important protein source in the human diet. However, global fish harvesting has increased 5 times during the last 50 years or so, partly because fishing technology has become more efficient and partly because of the increase in human population, which has increased demand for food. The oceans can probably support a fish harvest of about 100 million tons (90 million metric tons) of fish caught per year. As the fishing industry has expanded, these limits are being reached. Fishing vessels now have to travel farther and farther to get catches. Not only does this hurt the economy, there could also be as-yet-unknown disturbances to the marine ecosystem by driving fish stocks down in this way. People are also seeking to exploit the ocean for oil and gas. Drilling offshore began in 1947 in the Gulf of Mexico, and now there are thousands of such developments. It may be that efforts to extract oil and gas will go deeper still, despite the difficulties of the technology, with unknown effects on the marine environment. There has also been discussion about whether it might be possible to exploit the sea bed as a source of minerals. As the world’s population grows and industrial development spreads, the pressure to use the ocean as a resource can only increase, with unknown impacts on marine ecosystems.
Bleaching, symbiotic relationship, eutrophication, scum, dump, radioactive waste, nuclear power stations.,
Comprehension check-up
Exercise 31. Look through the text to find out who this text is intended for:
a) general reader; b) students of the faculty of Bioresources and Aquaculture;
c) professional veterinarians.
Exercise 32. Answer the questions and discuss the main idea of the text. Ask questions to the text.
1. What are the main environmental problems concerning marine ecosystems?
2. How do high temperatures impact to the symbiotic relationship between corals and algae?
3. What does eutrophication mean?
4. What is the reason of coral reefs destruction?
5. Where can dead zones be found?
6. What makes people develop fishing as a traditional activity?
7. What problems do people meet with by seeking to exploit the ocean for oil and gas?
Books
Cunningham, W.P., and A. Cunningham. Environmental Science: A Global Concern. New York: McGraw-Hill International Edition, 2008.
Kaufmann, R., and C. Cleveland. Environmental Science. New York: McGraw-Hill International Edition, 2008.
Rice, Tony. Deep Ocean. London: Natural History Museum, 2000.
Unit 5
Text A
Forests of the Sea: Phytoplankton & Marine plants
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VOCABULARY LIST TO TEXT A
| eukaryote n | [juːˈkarɪəʊt] | эукариот |
| seaweed n | [ˈsiːwiːd] | морская водоросль |
| loose adj | [luːs] | свободный |
| poisonous adj | [ˈpɔɪzənəs] | ядовитый, вредный |
| harvest v | [ˈhɑːvɪst] | собирать урожай |
| nourishment n | [ˈnʌrɪʃm(ə)nt] | питание |
| valve | ||
| fission n | [ˈfɪʃ(ə)n] | разделение |
| armor n | [ˈɑːmər] | защита |
| kelp n | [kelp] | бурая водоросль |
Exercise 47. Read and translate the following words and word combinations from English into Russian.
Phytoplankton, Diatoms, Dinoflagellates, Algae, loose group, chlorophyll, cyanobacteria, float freely, substrate, seaweeds, poisonous, nanoplankton, picoplankton, silica, frustules, chains, whole, zooxanthellae, bioluminescence, filaments, branched plants, broad flat plates, ruffled plants, motile spores, subpolar regions, bottom-dwelling animals, epiphytes.
