| Seasonal investigation and evaluation on plankton community and water quality were carried out in coral reef of Dazhou Island in 2013.Integrated use with Shannon—Weaver’s diversity indices,Richness index,Pielou’s indices and the single-factor water quality index,the eutrophication index,the organic pollution index of plankton are to analysis of variance,correlation analysis,clustering analysis.Compare the waters seasonal development trend of ecological environment in front harbor,the middle harbor and the back harbor.Based on the result obtained in 2013 of the plankton ecological environment confirms coral can grow and reproduce in Dazhou Island.Putting the coral reef base into quicksand on seabed in order to achieve the goal of restoring the coral reef ecosystem and transplanting coral reef.Coral transplantation on seabed of quicksand environment provides the reference case in order to protect the coral resources and contribute to the species diversity of Dazhou Island.The results of the study are as follows:(1)We collected a total of 104 phytoplankton species which belong to 6 phylnm and 58 genus.First,the Diatom has 104 species belonging to 37 genus.Then,the Dinoflagellates has 30 species belonging to 9 genus.The Cyanobacteria has 4 species belonging to 4 genus.The Chlorophyta has 6 species belonging to 6 genus.The Euglena and the Chrysophyta,1 species belonging to 1 genus.On the whole,the change rules of species was summer(53 species)<spring=winter(69 species)<autumn(73 species);We collect 17 kind of dominant species.The Cyclotella is always dominant species in different seasons.Species which belong to 2 phylum and 22 genus are red tied phytoplankton,3 species belonging to toxic algae.There were some dominant species of red tide phytoplankton,but they could not cause red tide;from the local,the front harbor of spring had the potential danger which cause red tide.(2)We collected a total of 47 zooplankton species belonging to 11 categories,Protozoa 19,Copepods 9,Rotifers 3,Cladocerans 1,Ostracoda 1,Tunicata 4,Siphonophora 1,hydromedusa 1,Chaetognatha 3,Mollusk 1,Planktonic larva 4.On the whole,the change rules of species was spring=summer(19 species)<autumn=winter(23 species);We collect 10 kind of dominant species.Protozoa as the first dominant species in winter and autumn,Protozoa’s species and density did not affect water quality,with Nauplius as abundant natural bait in coral reef ecosystems.(3)Most of the waters monitoring index of all the year round of Dazhou Island confirm to the second level of seawater quality standards of the states.Water quality is good,stable and suitable for coral to grow.The Dazhou Island coral reef waters is dystrophic.Most of organic pollution area are in good condition.Dazhou Island Water quality is the worst during spring.In summer,the water quality is bad as well.In autumnandwinter are better for coral reef in Dazhou Island.The main pollutant is DIN,overloaded DIN should not be the factor on the eutrophication.(4)The change of anthropogenic activities regularity which are caused by seasonal wind shifting and coral coverage will not significantly affect the phytoplankton species and density,zooplankton species and density and water quality of study areas.The phytoplankton species,zooplankton species and density have little difference from season to season.But there exists an apparent difference in phytoplankton density between spring and winter,the density in winter is much more than that in spring.For the temperature of water was more fit on the phytoplankton breeding.And there was different water quality in different season.The quantities of COD,DIP,DIN in spring and summer with that in autumn and winter showed negative correlation analysis.Phytoplankton Shannon—Weaver’s diversity indices,Pielou’s indices respectively with COD,DIP,DIN,showed negative correlation analysis.Zooplankton Shannon—Weaver’s diversity indices respectively with COD,DIP,DIN,showed negative correlation analysis,Pielou’s indices respectively with DIP showed negative correlation analysis.So the environmental factors play an important role in the plankton species and distribution.And we can regulate it through change the environmental factors.The similarity coefficient is low between the bay and the former and latter of the port in different seasons.Despite the differences was not apparent,the ecological state of affairs are various.(5)Building 67 "Transplantation of coral reef base under the quicksand circumstances on the seabed".And coral reef base is normal without dumping and inclining under the circumstances,and is not buried,after super typhoon.Transplanting 1665 individual of coral reef,and survival rate is as high as 95%above,and improving the coral coverage more than 5%,there are already ecological effect of attracting fish,large algae and other benthos,restoring coral water more than 6000 square meter.trying to "desert of seabed"into "oasis of seabed".It is the first of coral transplantation on seabed of quicksand environment of in nation,filling the domestic blank,it has important guiding significance on coral reefs and conservation of fishery resources. |
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