Caspian Sea 2011
State of the Environment of the Caspian Sea
The desertification process begins with deforesta- tion and is difficult to stop. On the Turkmenistan coast, desertification is a more natural process due mainly to water shortages and a reduction over time in amounts of precipitation. A rise in sea levels can lead to the inundation of lowlands. In some locations such inundations can result in the loss or reduction of wetland hab- itats — as has occurred in the Anzali lagoon in Iran – while in other areas inundations are a posi- tive factor, creating new wetlands – as in Komso- molets Bay in Kazakhstan. While sea level change does not substantially impact most Caspian spe- cies, it does affect some – in particular, it leads to the loss of seabird nesting grounds and seal “hauling out” sites – land areas where seals rest. Earthquakes and underwater volcanoes are a relatively common feature of the region and do not usually have any significant impact on ma- rine habitats and biodiversity levels. However, such events can have the effect of concentrating oil related materials in sea waters; most Caspian species can cope with such events. Volcanic ac- tivity was thought to be one of the main reasons behind a mass tulka death in 2000. Oil extraction, both offshore and onshore, is an actual as well as a potential danger in the region. Luckily, up to the present time, there has not been a large oil spill in the area. Due to the closed nature of the Caspian Sea, such spills have the potential of causing considerable loss of life in seawaters and along the shoreline, causing even small leaks to have a large impact. Oil pollution hot spots include those on the Azerbaijan coast where there are many old oil wells, and where onshore wells near the shore- line presenting a particular problem. Due to the geography of the Kazakhstan coast in the north- east of the Caspian Sea, small changes in sea levels can lead to the inundation of large areas, with many dozen kilometers of seawater intru- sion. As a result, oil wells can be inundated and sea waters polluted with oil residues and other toxic substances. The development of the oil in-
dustry has also resulted in the presence of larger and smaller vessels in the Caspian Sea and the growth of coastal infrastructure. This has often had a negative impact on various habitats and species, the most important of which is the dis- turbance of bird nesting and seal pupping cycles. Water pollution and the accumulation of pol- lutants at lower depths in the Caspian Sea have long been recognized as having a significant im- pact on bioresources and biodiversity. Diseases which have affected all sturgeon species are believed to have been the result of long-term exposure to pollutants. There are many sources of pollution in the Caspian Sea region, where river waterways are considered to be the main pollution factor. The pollution might originate far from the Caspian Sea, but due to the Sea’s closed nature, pollution accumulates within the its vast basin. The most important pollut- ants found in the Caspian Basin are heavy met- als, and various forms of pesticides and other chemical substances. Though such pollutants have differing origins and effects, they can cause liver disease, other ailments in animals, and even the death of organisms. Many species of phytoplankton and zooplankton are very sen- sitive to very low concentrations of pollutants and are therefore very vulnerable. Agriculture is one of the main sources of pol- lution in the region. Beside pesticides, the ag- ricultural sector also uses large quantities of fertilizers and produces sizeable quantities of livestock waste. Historically, eutrophication was not a problem in the Caspian Sea region. An increase in fertilizer inputs plus the accu- mulation of livestock waste, along with a rise in temperatures, could have been the cause of a massive algae bloom in the South Caspian Sea in 2005. A similar but smaller bloom ap- peared again in 2006. However, the reasons for such blooms are not fully understood: climate change – with higher temperatures and less winds experienced over lengthy periods – is one likely cause. Another is seawater plant growth due to fertilizer and livestock waste runoffs.
Made with FlippingBook - Online catalogs