The Spatio-temporal Distribution And Carbon Sequestration Mode Of Thraustochytrids In Different Habitats In Coastal Waters

The coastal region of ocean represents a special ecological system connecting the terrestrial land and ocean.In the coastal waters,a large amount of resources are stored,which is closely related to the survival and development of human beings.The coastal waters has high primary production.Quite large number of excessive primary production becomes detritus and becomes availabled to heterotrophic protists.There are a number of complex organic matters in the different chemical forms and sources in the coastal waters.Bacterioplankton has long been considered to be the main decomposers and consumers in the marine ecosystem and plays a key role in the nutrient cycling in the ocean.The unicellular heterotrophic protists,which are represented by the lineage of thruastochytrids,are recently considered to play an assignable role in the ecosystems.Thraustochytrids are widely distributed in the ocean and estuaries and it is thought to play an important role in the marine carbon cycling because of their high biomass.In order to study the distribution and living status of thraustochytrids in different habitats,water samples were collected from two coastal regions in the Shenzhen and Qinhuangdao.In this report,the average abundance of thraustochytrids in Qinhuangdao is higher than that in Shenzhen(660 cells/mL and 315 cells/mL).We conducted research to obtain the abundance data of thraustochytrids in water samples collected in different months and stations with one-way analysis of variance(ANOVA).We observe a significant difference in temporal distribution pattern(F=4.883,P<0.01)in Shenzhen while has no significant difference was detected in Qinhuangdao.The highest biomass ratio between thraustochytrids and bacterioplankton in Qinhuangdao and Shenzhen are 125.02% and 257.2%,and the average biomass ratio are 40.89% and 90.7%.It indicates that the thraustochytrid in Shenzhen has a greater potential in nutrient carbon sequestration in the coastal water ecosystem.The average proportions of thraustochytrids in the total heterotrophic protsits are 16.4% and 16.82% in Qinhuangdao and Shenzhen coastal waters.No significant variations in the population abundance ratio between thraustochytrids and bacterioplankton were observed in different oceans and proportion.It indicates that the thraustochytrids keep a high and stable status in heterotrophic protists even in different habitats.In a conclusion,the thruastochytrids play an important role in the carbon cycling and carbon sequestration in marine ecosystem.