Studies On Diatoms Of Da'erbin Lake And Swamps Around It In Daxing'anling Mountains

The swamp is a systematic important component of natural ecology contained rich alga resource among them. Swamp of our country area is very vast, scatter mainly in Xing'an Mountains, Qinghai-Tibet Plateau and Xinjiang north part area, among them the Daxing'anling Mountains which located in Chinese Northeast has swamp rates being amount to 9%, the swamp type is various, and there is a very important distribution area of swamp, but the alga to that area investigates haven't been reported till now. In this paper, preliminary investigation and study have been done about the diversity of diatom in Da'erbin lake and swamp in the surrounding area in Daxing'anling Mountains and provide important data to alga resource investigations, diversity of alga and swamp ecology research to Daxing'anling Mountains Territory, also provides the basis data to our country's alga investigation.Da'erbin lake located in Aershan, southwest of Daxing'anling Mountains, Inner Mongolia, altitude 1288 meters, that is formed by the Plinian eruption lava blocks up the dammed lake and the river valley from the ancient times. Lake vicinity has the eutrophic swamp , the middle nutrition swamp and the moss swamp which is the oligoteophic type. This area is the most representative distribution area of swamp in Daxing'anling Mountains.We have carried out four times of alga specimen collection in Da'erbin lake and their vicinity swamp in August 2004, August and October 2005, May 2006, including three seasons, together collect specimens striding over spring, summer, autumn. The light microscope is made use of observation on all specimens and taken photos, unit making use of scanning electron microscope to observation and taken photos, 262 taxa have been identified, including 201 species, 59 varieties and 2 forms, which belong to 44 genera, 10 families, 6 orders, 2 classes. In these taxa, 72 taxa including 48 species, 65 varieties and 1 form are new records in China.In Centricae, 1 order has been identified.①Coscinodiscales: there are only 5 taxa in total, including 1 family 2 genera 4 species 1 variety.In Pennatae, 5 orders have been identified.①Araphidiales: there are 26 taxa in total, including 1 family 8 genera 20 species 5 varieties 1 form. In these taxa, 2 species 1 variety are new records in China.②Raphidionales: there are 28 taxa in total, including 1 family 1 genera 20 species 8 varieties. In these taxa, 1 species 1 varieties are new records in China.③Biraphidinales: there are 163 taxa in total, including 3 families 24 genera 121 species 41 varieties 1 form. In these taxa, 39 species 19 varieties 1 form are new records in China.④Monoraphidales: there are 8 taxa in total, including 1 family 2 genera 7 species 1 varieties. In these taxa, 3 species are new records in China.⑤Aulonoraphidinales: there are 32 taxa in total, including 3 families 7 genera 29 species 3 varieties. In these taxa, 3 species 2 varieties are new records in China.The species composition and distribution of diatom in Da'erbin lake and swamp in surrounding area were discussed preliminarily. The distribution of diatom in Da'erbin lake having follow characteristic:1. Da'erbin lake and swamp around it have diversity rich diatom species, the main characteristic is that the species are abundant but quantities are few, mainly of these taxa are general widespread species, most of all is the world's widely distributed species or scattering broadly in the Northern Hemisphere. 2. Centricae class species is few, Pennatae is many. In Centricae, only 2 genera 4 species 1 varieties are identified, the others 42 genera 197 species 58 varieties 2 forms are all belong to the Pennatae.3. Be addicted to acids species are outstanding, and some high mountain cold water species appeared, some representative species of typical habitat also discovered.4. In the habitat conditions, the occasional species are many, the dominant and common species are rare. In all taxa only 8 species 1 variaty becoming more obvious dominant species and these species are all present in autumn.5. Among three seasons, summer has the most abundant composition, 231 taxa are identified. In spring, the species are less, 155 taxa are identified in total. In autumn, 193 taxa are identified in total. Species appearing in all the three seasons accounts for 45% of all the taxa.6. In the three kinds of habitats, 164 taxa are identified in the lake. 167 taxa are identified in the surrounding swamp. Lakeside waterweeds adherence zone is the lake and swamp transition belt, diatom rich degree is maximal, most dominant species appears in this habitat, 197 taxa are identified in there. Species appearing in all the three kinds habitats accounts for 33% of all taxa.