V. Yurchenko, Сandidate of Аgrarian Sciences, Associate Professor
Kharkiv State Zooveterinary Academy, Kharkiv
Temperature is the most important climatic factor that often limits the existence and geographic distribution of organisms. More than a century, there is an increase in the average temperature on the surface of the ocean. As a result, organisms have to adapt to new conditions. The first consequence of changes in environmental conditions is a displacement terms of seasonal phenomenons. The sharp warming water has a negative effect on the reproductive performance of fish, causes a heat stress, stimulates the contamination of fish parasites and infectious diseases. Because of global warming, many species of fish significantly reduced in size. The water temperature determines the sex of some species. To the end of the century the ratio of males and females of some fishs may change from the usual 50% to 75 – 98%. Thus, these species may disappear.
Increasing the ocean temperature causes migration of marine organisms. Changing ocean dynamics particularly adversely affects the those species that are not able to migrate, and leads to their death. Global warming and rising acidity of the waters of the oceans has caused the destruction of 20% of all coral reefs in the world.
An important aspect of the impact of global warming is reducing the amount of aquatic plants. This causes the reduction populations consuments – the next level trophic chain. The result is changing species composition of ecosystems and nature their functioning. Quite a lot of indirect climate effects that affect aquatic organisms, including changes chemical composition of the ocean (concentration of oxygen, carbon dioxide, etc.). For example, reducing the content of oxygen in the sea water leads to a decrease in fertility and growth of marine organisms. In some cases, negative trends in marine fishery related to global warming, can be overcome through mariculture or aquamelioration.
Key words: climate change, global warming, temperature, environmental conditions, aquatic ecosystems, aquatic organisms, fishs, number of populations, seasonal phenomenons, reproductive function, migration, corals, marine fishery.