Subproject 子项目 7

Subproject   子项目   7

Diversity and community composition of coastal benthic invertebrates related to the dispersal of land-derived pollutants.

Participating scientists

Dr. Inga Nordhaus (ZMT), Dr. Daoru Wang (HAOFS)

Project description

Human activities, e.g. the operating of aquaculture ponds and the related discharges may influence benthic diversity in coastal waters. The decline of invertebrate species in polluted coastal waters can be related to hypoxia, acidic conditions and high organic enrichment in sediments, or can be explained with the toxicity of specific organic contaminants. A decline of species holding important ecological functions as a result, may negatively affect the whole ecosystem.

The major goal is to determine the diversity, distribution and community composition of macrobenthic invertebrates in relation to water and sediment parameters, including the concentrations of nutrients and contaminants in the vicinity of aquaculture facilities and at reference sites. Possible correlations between benthic diversity, community composition and environmental parameters will be determined with multivariate statistics. The stress level and condition factors of selected species will be assessed and their functional roles investigated. This study will provide the basis for a first assessment of pollution effects on benthic diversity and related ecosystem functions.

Information to our field campaign

What have we done in Hainan during our field work?

• Collecting benthic invertebrates for the determination of diversity, abundances and biomass
• Collecting benthic invertebrates and mangrove leaves for the analysis of carbon and nitrogen concentration as well as stable isotopes of carbon and nitrogen in their tissues
• Measurement of growth rates (size, biomass) of economically important bivalve species over seven weeks
• Sampling of sediments for the determination of the grain size distribution, the analysis of carbon and nitrogen concentration and stable isotopes of carbon and nitrogen
• Sampling of water for the analysis of nitrate, nitrite, ammonium, and phosphate
• Measuring temperature, salinity and pH values in the pore water
• Filtering of pore water samples for nutrient analysis
• Determination of mangrove tree diversity and density

What have we done in the field laboratory?

• Sieving of sediment samples to extract the benthic invertebrates
• Labelling and preservation of samples (+ 4% Formaldehyde)
• Sorting and identification of benthic invertebrates
• Measuring benthic invertebrates: length, width, wet biomass (without shells)
• Extraction of haemolymph for counting of hemocytes
• Dissection of potential sentinel species to separate the organs (hepatopancreas, gonads, gills, foot)
• Weighing and drying of organs for later analysis of trace metals and calculation of condition indices
• Weighing and drying of sediment samples for later determination of organic carbon and nitrogen, stable isotopes of carbon and nitrogen, and trace metals
• Determination of conditional biomarkers (including condition factor, gonado-somatic index and hepato-somatic index ) and biochemical biomarkers (including Acetylcholinesterase, Lipid Peroxidation, Glutathione S-Transferase, Superoxide Dismutase, Catalase)
• Exposure experiments with the Asian green mussel Perna viridis and an organotin compound called tetraphenyltin in different concentrations

Where did we collect our samples?

Basic information about benthic organisms in our Fact Sheet

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