Exercise 22. Make up collocations using words from both columns

temperature	zones
upwelling	fluctuations
fishing	current
oceanic	content
rainfall	chemistry
water	ground
nutrient	pattern

Exercise 34. Give special characteristics to each oceanic zones according to the table below:

Pelagic zone	Photic zone	Upwelling zone

Exercise 9. Give the explanation for the following words. What is your opinion?

Upwelling zone, neritic province, photosynthesis , greenhouse warming, photic zone.

Exercise 35. Test yourself by answering these questions and summarize given information.

What does upwelling zone mean?

Where is pelagic zone found?

What determines the diversity of ocean inhabitants?

What does photic zone mean?

What is the the primary food source for all marine life?

What is nekton?

How do you explain the ocean moderating effect on world climate?

What alters rainfall patterns?

What causes evaporation?

What effect on the atmosphere has the enormous productivity of phytoplankton?

Text B

Brackish water.

VOCABULARY LIST TO TEXT B

brackish adj	[ˈbrakɪʃ]	солоноватый
tidal cycle n	[ˈtʌɪd(ə)l] [ˈsaɪkəl]	приливо-отливный цикл
prairie n	[ˈprɛːri]	прерия
snowmelt n	[ˈsnəʊmɛlt]	таяние снегов
ion n	[ˈʌɪən]	ион
creek n	[kriːk]	небольшой залив, бухта
flood n	[flʌd]	наводнение, разлив
dilute v	[dʌɪˈl(j)uːt]	растворять
eel n	[iːl]	угорь
spawning n	[ˈspɔːnɪŋ]	нерест
eelgrass n	[ˈiːlɡrɑːs]	зостера, морская трава

Exercise 36. Read and translate the following words and word combinations from English into Russian.

Brackish water, tidal cycles, diluting effects,mangrove swamps, killifish, creeks, spawning migration, cord grass, swings, brackish habitats, ecological opportunity, physiological stresses, brackish water, severe storm, occasional inputs, salt concentrations, cord grass, aquatic eelgrass, eel, spawning, snowmelt, dilute, creek.

Read the text and translate. Be ready to discuss.

Brackish refers to water with a level of salinity between freshwater and seawater (the latter has a salt concentration of about 3.5%, or 35 parts per thousand). Brackish water originates by the mixing of seawater and freshwater, and is most common near the coasts of the oceans.

The word is derived from the Dutch brack, which means “salt”. The term was first used to describe portions of potable water table which had been contaminated by salt water in the 1500s. The mixing of salt and fresh water was created mildly salty water which was not salty as seawater, but still distasteful. Many people also noted that the brackish water was harmful, due to unique microorganisms which cause human illness that thrive in it.

Brackish water can occur as enclosed system such as lake and pond that receive occasional inputs of oceanic water during severe storms. Brackish water also occur as coastal estuaries or salt marshes that are more frequently flooded with saline water as a result of tidal cycles. Sometimes, brackish water can occur far inland, for example, in parts of the prairies of North America where saline ponds and wetlands have variable salt concentrations depending on the diluting effects of recent rains or snowmelt. Two of the most ecologically important types of brackish environments are river estuaries and mangrove swamps. The Baltic Sea is the largest region of brackish water in the world.

The salt concentration of water is highly influential on the transport of ions across cellular membranes, the availability of nutrients in soil, and for other reasons. Most species can tolerate either saltwater or freshwater, but not both. However, organisms that live in brackish habitats must be tolerant of a wide range of salt concentrations (such species are known as euryhaline). For example, the small fish known as killifish (Fundulus spp.) are common residents of brackish coastal habitats known as estuaries, where within any day the salt concentration in tidal pools and creeks can vary from that typical of freshwater to that of the open ocean. Other fish such as salmon (e.g., Salmo spp.) and eels (Anguilla spp.) move to or from marine water during their spawning migrations, in the process moving from environments characterized by the salt concentration of full seawater, through brackish, to freshwater. Animals that live in or move through estuaries must be tolerant of the physiological stresses associated with such large and rapid changes in salinity, as must the plants of those habitats, such as the aquatic eelgrass (Zostera spp.) and the cord grass of salt marshes (Spartina spp.).

The environmental conditions of brackish water are highly stressful for organisms that cannot tolerate such wide swings of salinity. However, for those relatively few species that are tolerant of such difficult environmental conditions, the brackish habitats represent a relatively uncompetitive, ecological opportunity to be exploited.

Exercise 36. Read and translate the following words and word combinations from Russian into English.

Степень разжижения, солоноватые воды, приливный цикл, мангровые болота, небольшой залив, сильный шторм, концентрация соли, нерестовая миграция, солоноватая среда обитания, большие колебания солености, быстрые изменения, заполняемый во время прилива, физиологическое напряжение, оказывающий сильное влияние.

Exercise 37. Give the explanation for the following words and remember them.

Brackish water, mangrove swamps, killifish, spawning. tidal cycles.

Exercise 38. Test yourself by answering these questions and summarize given information.

1. What is brackish water?

2. What level of salinity has brack water?

3. Where can brackish water occur?

4. What was the term “brackish water” first used to describe for?

5. Can brackish water cause health problems?

6. What are the most ecologically important types of brackish environments?

7. What effect does brackish water have on different types of fish?

8. Can the environmental conditions of brackish water be highly stressful for organisms?

9. What organisms are the most susceptible to wide swings of salinity?