The biological content of ballast water in China:A review

The introduction of species through the release of ballast water has become a major threats to marine biodiversity and ecosystem function worldwide.China is one of the top trading countries,yet little is known about exotic species in the ballast water of ships coming to its ports.Here,we review the biological surveys of ballast water from major Chinese ports.These surveys reveal that 40 species of nonindigenous phytoplankton that,belong to 25 genera and five phyla,have been observed in ballast water.The dominant species are diatoms and dinoflagellates.There were 17 red-tide causing species observed,five of which are noxious algae.Seventeen species of non-indigenous zooplankton have been reported,most of them(11)copepods.There were also 22 species of pathogenic bacteria recorded,including Vibrio alginolyticus,V.carchariae,V.parahaemolyticus,and V.vulnificus.These studies show that species introduction through ballast water potentially a serious threat to the ecology and human health in China.More research,including collaboration with the international community,is urgently needed to address this problem.

Community structure of benthic macroinvertebrates in reclaimed and natural tidal flats of the Yangtze River estuary

Previous studies have found differences between communities of benthic macroinvertebrates living in constructed tidal flats compared with natural ones.We analyzed the distributional characteristics of benthic macroinvertebrates in a blowing sand reclamation area(Area A),a dike-building silting area(Area B),an out-ofsiltation area(Area C),and a natural tidal flat(Area D)in order to characterize the community structure and diversity of benthic macroinvertebrates in a human-disturbed estuarine tidal-flat wetland.A total of 32 benthic macroinvertebrate species were identified(Area A=7;Area B=12;Area C=10;Area D=27).The diversity index was variable where:Area B<Area C<Area A<Area D.A higher average annual abundance of benthic macroinvertebrates was found at Area B(840.43±569.23)ind/m^(2) than in Area D(203.00±5.85)ind/m^(2),Area A(42.87±10.21)ind/m^(2),and Area C(17.64±1.50)ind/m^(2).The biomass in Area C(3.18±0.39)g/m^(2) was lower than in the other areas.One-Way ANOVAs detected significant differences(P<0.05)in the abundance and biomass within Area B among seasons;however,there were no significant seasonal differences(P>0.05)in the abundance and biomass of Areas A,C,and D.An abundance/biomass curve showed that the habitat in Areas A,B,and C could be categorized as moderately disturbed,whereas Area D was categorized as undisturbed.The results of cluster analysis suggested distinct assemblages in the four sampling areas.Reclamation raised the altitude of tidal flats,weakening the tidal power and changing the physical and chemical parameters of the water,leading to a change in the community structure of benthic macroinvertebrates.

Seasonal variation and longitudinal distribution of copepods in the main river area of the Three Gorges Reservoir

The ecosystem of the Three Gorges in the Yangtze River was changed into an artificial lake(reservoir)ecosystem after impoundment in June 2003.We surveyed the seasonal variation and spatial distribution of copepods from April 2004 to January 2005 in order to provide data for clarifying the successional pattern of the ecosystem.From Jiangjin to Maoping,eight copepod species were collected and classified into Calanoida(2),Harpacticoida(1),and Cyclopoida(5).Among them,Mesocyclops pehpeiensis,M.leuckarti and Sinocalanus dorrii had a relatively wide distribution.No distinct difference in species number was found among the sampling sites,but the species composition was different.Species composition,distribution and density of copepods showed significant seasonal variations.In addition,copepod density showed an obvious gradient with the distance from the reservoir dam:the nearer to the dam,the denser the copepods.

Analysis of the diet of the tadpole shrimp, Triops sinensis, in paddy fields of Shouchang River watershed

The tadpole shrimp,Triops sinensis,was discovered in the paddy fields of the Shouchang River watershed.The gut contents of the shrimp from these field populations were analyzed in order to quantify their dietary patterns.Some species of tadpole shrimps were found to prey on mosquito larvae as well as uproot weeds.Mosquito larvae and weeds were seldom found in the paddy fields which the tadpole shrimp inhabited in the Shouchang River watershed.The results further showed that the larvae of these tadpole shrimp mainly feed on algae and rice lamina.The tadpole shrimp could feed on animal food including protozoa,nematodes,rotifers,crustaceans,and aquatic insect larvae,though the animal food was subsidiary.