Community Structure Of Macrozoobenthos Research Articles

The Community Structure and Biodiversity of Macrozoobenthos in Daoguanhe Reservoir, Hubei Province

1999年对湖北道观河水库大型底栖动物进行6次采样,共检出大型底栖动物17种,隶属4门16属.其中软体动物3种,环节动物5种,节肢动物8种,线形动物1种.密度和生物量分别为142ind/m²和0.99g/m².优势种类为大红德永摇蚊和霍甫水丝蚓.密度季节变化顺序为春季 >冬季 >秋季 >夏季;生物量季节变化为春季 >冬季 >夏季 >秋季.密度和生物量的水平分布为上游 >库湾 >中游 >下游.生物量与水深呈负相关关系;与水温、底泥TN、TP无显著相关关系.应用Goodnight-Whitley生物指数等对水质进行评价,结果显示该水库受到中等污染.提出在深水水库中不宜用Shannon-Wiener指数和Margalef指数等多样性指数评价水质.;In order to provide theoretic base for reasonable utilization of fisheries resource and to offer ecological strategy to the assessment and protection of aquatic environment, we studied the community structure and biodiversity of Daoguanhe Reservoir, Hubei Proince bimonthly in 1999.Macrozoobenthos were sampled from thirteen sites.Seven taxa of zoobenthos were identified.They belonged to 16 genera, 9 families, 4 phyla.Those were 3 species of mollusks, 5 species of oligochaetes, 8 species of aquatic insects and 1 of nematode.The density and biomass of the benthic animals were 142 ind/m² and 0.99 g/m², respectively.The dominant species were Tokunagayusurika akamusi and Limnorilus hoffmeisteri.The seasonal density variation order was spring > winter > autumn > summer;and biomass ranked as spring > winter > summer > autumn.The horizontal variation tendency of both density and biomass were the upper reaches > the reservoir bay > the middle reaches > the lower reaches.There was a significant negative relation between benthos biomass and water depths;but no pronounced relations between biomass and water temperature, sediment TN, TP or pH.Water quality of the reservoir was evaluated using Goodnight-Whitley index and other biological and biodiversity indices.The results demonstrated that the reservoir was polluted.We suggest Shannon-Wiener index and Margalef index are not fitted to the assessment of water quality in deep reservoirs.

Long-Term Effects of "El Niño" on The Structure of Soft-Bottom Macrozoobenthos Communities in Northern Chile

Long-Term Effects of "El Niño" on The Structure of Soft-Bottom Macrozoobenthos Communities in Northern Chile

Impact of Eutrophication on Biodiversity of the Macrozoobenthos Community in a Chinese Shallow Lake

ABSTRACT Comparative studies on community structure and biodiversity of macrozoobenthos were carried out in three lake areas with different states of eutrophication (mesotrophic, eutrophic and hypereutrophic) in a shallow subtropic lake (Lake Donghu) in the middle basin of the Yangtze River of China. Thirty-three taxa (including six Mollusca, five Oligochaeta, 15 Chironomidae and seven other zoobenthos) were found during February 1998 to April 1999. The results show that the more eutrophic the lake water, the lower the macrozoobenthos species diversity (measured as species number, diversity index, and K-dominant curves). Abundance of the oligochaete Limnodrilus hoffmeisteri was positively correlated with the degree of eutrophication, which was due mainly to its ability to tolerate low dissolved oxygen. The chironomid Tanypus chinensis also thrived in the hypereutrophic environment; however, it was less endurable to eutrophication than L. hoffmeisteri.

Sediment quality assessment in the delta of rivers Rhine and Meuse based on field observations, bioassays and food chain implications

The quality of sediment was assessed in 46 sites in the delta of the rivers Rhine and Meuse (The Netherlands) by means of physical-chemical analysis, field observations on the macrobenthic community structure, accumulation studies and bioassays using Chironomus riparius, Daphnia magna and Photobacterium phosphoreum. The results of chemical analyses were classified using national criteria for sediment quality. Results of field studies and bioassays were classified using criteria derived from research in reference areas or based on data from literature. Risk assessment was carried out according to the sediment quality triad and by means of multi criteria analysis (MCA). The Triad approach was used to demonstrate causal relations between effects on the macrozoobenthos community structure, effects demonstrated in bioassays and sediment pollution. This was done by making a comparison of sediment contamination levels with toxicity data from literature for the test organisms of the bioassays. Using the MCA method, for each site a numerical value was derived for total environmental risk in the present situation, based on observed effects. In this way, a relative risk ranking of all sites was realized. The MCA values for the present situation were also compared with MCA scores based on estimated risks after remediation in 1995, in order to set priorities for sites where remediation is expected to cause a significant reduction in environmental risk. In most of the 46 sites studied so far, the macrofauna community was poorly developed, judged by a low number of benthic species, low abundances and a high dominance of species regarded as relatively tolerant to chemical pollution. In bioassays high sediment toxicity was demonstrated for 24 sites. Using the sediment quality triad approach, 25 sites were identified as areas where pollution can be held responsible for the effects observed in the field. From a comparison of contaminant concentrations in different types of food with maximum tolerable risk levels, and the application of a bioaccumulation model it was concluded that the sediment pollution also implies high risks for plant-, benthos- or fish-eating birds (secondary poisoning of top predators). In the Nieuwe Merwede highest MCA risk scores were found for shallow parts where highly polluted sediments are found. It is concluded that the sediment quality triad and the MCA provide additional information which can be used to establish priorities for remedial action. Based on an ecotoxicological evaluation of the improved quality of new sediments that will be deposited after removal of the polluted sediments in the Nieuwe Merwede, it is concluded that in this upstream part of the Rhine delta remedial action will be effective.

Community structure of planktons and macrozoobenthos, with special reference to pollution in the River Khan (India)

This paper presents an assessment of water quality of the River Khan, which passes through Indore and is subjected to sewage and industrial pollution. The analysis of various pollution parameters showed an increase when the sewage and industrial channels joined the river. Changes in the biotic communities, such as phytoplankton, zooplankton and macrozoobenthos, have been explained numerically with the help of a diversity index and showed a decrease in diversity values with an increase in pollution, along with a correlation with physico‐chemical aspects. Genera tolerant to various degree of pollution has also been identified. The extend of pollution by certain heavy metals such as Cu, Zn, Ni, Cr, Cd and Hg has also been studied.