Preliminary Stauy On Taxonomyof Freshwater Diatoms In Coastalislands Of Fujian Province

From 2020 to 2021,diatom specimens were collected from six coastal islands in Fujian Province,including Yushan Island,Dongshan Island,Sandu Island,Pingtan Island,Meizhou Island and Xiamen Island.A total of 59 specimens were collected and120 permanent sides were made.Habitats include: reservoirs,lakes,rivers,wet stone walls,dry stone walls,wells,puddles,ponds.Light microscope(ZEISS Imager.A2)and scanning electron microscope(Hitachi S-4800)were used to study the taxonomy of diatom plants in the sides.The main results are as follows:1.There are abundant species of freshwater diatoms in the coastal islands of Fujian Province.A total of 33 families,83 genera and 419 taxa of diatoms were identified,including 11 taxa of newly recorded species in China,including: Synedra bacilaris(Grunow)Hustedt、Opephora schwartzii(Grunow)Petit ex Pelletan、Actinella brasiliensis Grunow 、 Eurotia asterionelloides Husledt 、 Placoneis yucatanensis Lange-Bertalot、Encyonopsis medicinalis Bahls、Gomphosphenia oahuensis(Hustedt)Lange-Bertalot、Brachysira irawanoides Lange-Bertalot & Moser、Sellaphora pupula f.capitata Skvortzow & Mayer、Neidium juba Carter、Psammodictyon constricta var.subconstricta Grunow.The morphological characteristics and distribution information of each taxa were described in detail.All species were accompanied by LM photos,and some species were accompanied by SEM pictures;2.Bacillariophycidae is the main diatom species in the coastal islands of Fujian Province,including 45 genera and 350 taxa,accounting for about 84.5% of the total.Followed by Coscinodiscophyceae,including 12 genera and 35 taxa,accounting for about 8.47% of the total;Fragilariophyceae is the least,9 genera and 29 taxa,accounting for about 7.03% of the total;3.Among the 83 genera identified,Eunotia was the most abundant,with 29 taxa;and only one taxa was observed in 32 genera;4.The dominant species in the coastal islands of Fujian Province include:Aulacoseira ambigua(Grunow)Müller,Aulacoseira granulata var.angustissima Müller,Cymbella subaequalis Grunow,Encyonopsis robusta(Hustedt)Bahls,Achnanthes kuwaitensis Hendey,Achnanthidium affine(Grunow)Czarnecki,Achnanthidium catenattum(Bily & Marvan)Lange-Bertalot,Humidophila contenta(Grunow)Lowe et al.,Brachysira microcephala(Grunow)Compère,Navicula cryptotenella Lange-Bertalot,Navicula lundii Reichardt,Nitzschia soratensis Morales & Vis.5.The species composition and ecological distribution of diatom plants in six islands along the coast of Fujian Province were preliminarily analyzed.There are many diatom species in the coastal islands of Fujian Province,mainly freshwater common species,and most of them are world-wide.Most of the species were distributed in reservoir habitats,and 292 taxa were found.In the lake habitat,208 taxa were found.164 taxa were found in the wet stone wall.A total of 119 taxa units were found in the river habitats,41 taxa were found in the pond habitat;35 taxa were found in the well habitat;26 taxa were found in puddle habitats.The least is found in the dry stone wall,with a total of 19 classification taxa.6.From the distribution point of view,Sandu Island found the most species,a total of 242 taxa were found;Yushan Island followed,a total of 207 taxa were found.A total of 161 taxa were found in Dongshan Island.A total of 130 taxa were found in Pingtan Island.A total of 118 taxa were found in Meizhou Island;A total of 112 taxa were found in Xiamen Island.7.Based on the biogeographic analysis of diatom distribution characteristics data of 12 sampling sites in coastal islands of Fujian Province,it was found that the main influencing factors of diatom distribution in coastal islands of Fujian Province were salinity,conductivity,annual average rainfall,population,coastline length,island area,monthly average temperature,and near-land distance.8.The β diversity of freshwater diatoms in the coastal islands of Fujian Province is high,and the proportion of species turnover components is much larger than that of species nested components,indicating that diatom plants have good adaptability to different habitats.The difference in species composition mainly comes from the species succession between the islands.This study provides reference materials for the study of diatom biodiversity in China,and provides an important reference for the study of freshwater diatoms in coastal islands.Accumulate important basic data for the study of diatom biodiversity in China and the diversity of algae in Fujian Province.It also provides important basic data for subsequent studies on algae ecology,water environment quality assessment,scientific and rational development and utilization of island resources,and protection of ecological environment.