Caspian Sea 2011

State of the Environment of the Caspian Sea

Euglena algae constitute a minor presence with only eight species known in the Caspian Sea. They are distributed in small amounts in all parts of the Sea. Green algae constitute 138 species and 20 forms from 49 genera in the Caspian Sea, though only 70 species were found in surveys between 1990 and 2008. Most of the green algae are in freshwater and are distributed around river deltas. Maximum diversity and abundance levels were found in the Volga Delta and in the North Caspian Sea. Only 16 species were found in the Central and South Caspian Sea, along the eastern coast. Charophytas are small metaphytas up to 20- 40 cm. in length. Only seven species from two genera have been found in the Caspian Sea. They live at shallow depths in the South and Central Caspian Sea and are a preferred food source for many waterfowl. In total, there are 620 species and 48 forms of algae in the Caspian Sea. Seventeen of these are endemic to the region while four are recognized as having been introduced. There are 132 species of merged, submerged and fluctuant High plants from 44 genera. Only 25 of these are found in the Caspian Sea – the remainder are distributed in surrounding deltas and wetlands. Giant reed Phragmites australis is the most common submerged plant. It can be found in all locations sur- rounding the Caspian Sea. Common merged plants are eelgrass, pondweed, parrot’s-feather, widgeon grass, najas, and hornweed. The number of species in the Volga and Kura deltas are similar - 56 and 47 respectively - but species composition differs. Maxi- mum species diversity was found in Dagestan (117 species), an area where the floras of the north (Vol- ga) and the south (Kura) meet each other. Along the Iranian coast, 17 species of aquatic plants have been found, while along the coast of Turkmenistan only seven have been found. Twelve species have been listed in the Red Data Books of the Russian Federa- tion, Dagestan, Azerbaijan, and Kazakhstan.

All known Protozoans from the Caspian Sea are foraminifers. Only 27 species are identified in the North Caspian Sea, and 11 species in the South Caspian Sea. Planktonic protozoans have not been studied. There are about 400 species of Infusoria in the Caspian Sea of which 20 species are endemic. There are sedentary, planktonic and colonial spe- cies. Most of these species have been found over the last 15 years due to the intensive study of benthic communities in the vicinity of oil wells. These figures are, however, not definitive and are likely to change as studies continue. Five species of Jellyfish currently inhabit the Caspian Sea – three are introduced while two are autochthons. One species ( Moerisia pallasi ) is en- demic to the Caspian Sea. A sixth species, Aure- lia aurita, was found only once in 1999 and never found again. Some species of freshwater hydras are found in shallow-water deltas. One Comb jelly species has been introduced into the Caspian Sea – Mnemiopsis leidyi. The in- vasion of this jelly during the late 1990s repre- sents one of the main environmental issues in this unique ecosystem, and is considered as one of the world’s major marine ecosystem invasive species occurrences. Many Flat worms are parasites and the small group of Turbellaria live in the wild. Twenty five species of Turbellaria are identified in the Cas- pian Sea, and 18 of them are endemic. Most studies of this group of organisms were carried out more than 100 years ago and future studies could change our understanding of this group of organisms. The same is true for Nemertins — never identified at a species level in the Caspian Sea and found only near the Volga and Ural del- tas. Only one species of Entoprocta has been found in the Caspian Sea – Barentsia benedeni. It was probably introduced from the Black and Azov seas; it is now found only along the eastern coast of the South Caspian Sea.

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