Preliminary Study The Spatial And Temporal Distribution Of Carbon And Nitrogen Isotope In Ostrea Rivularis Gould And The Response To Inorganic Nitrogen,zhanjiang Harbor

Ostrea rivularis Gould, Phytoplankton, Sediment and Benthic-Macroalgae were collected to investigate the stable isotope ratios of carbon(δ13C) and nitrogen(δ15N) and Sea wate were collected to Inorganic nitrogen( nitrite nitrogen, nitrate nitrogen, ammonia nitrogen) in 2008 to 2009, Zhanjiang Harbor. All datas calculate by statistical survey to analysis the food source of Ostrea rivularis Gould, the relation Inorganic nitrogen andδ15N of tissues. the main results are shown as follows:(1)It was not relation between the stable carbon and nitrogen isotope enrichment of tissues and the age of Ostrea rivularis Gould. Different tissues had the same enrichment or dilution trend on stable carbon and nitrogen isotope. In spatial, the same tissue had different enrichment grade ofδ13C andδ15N values. In temporal, only the visceral mass were bigger change on seasons, And itsδ13C andδ15N values were pronounced change in all tissues.(2) Theδ13C andδ15N values of adductor muscle,mantle tissue,ctenidia and visceral mass on Ostrea rivularis Gould were differed from each other, the rang ofδ13C values were -24.13‰～-15.01‰,-23.81‰～-16.43‰,-24.37‰～-16.36‰,-25.16‰～-17.05‰;, and the range ofδ15N values were 7.70‰～14.26‰,7.13‰～13.23‰,6.39‰～13.55‰,5.74‰～12.74‰. Theδ13C和δ15N values of adductor muscle were best enrichment, the visceral mass were best dilution, relatively. The enrichment trend were: adductor muscle>ctenidia>mantle tissue>visceral mass. So, when it gained nutrition from SPOM and SOM, the flow pathway in its body was: viscera mass→mantle tissue→ctenidia→adductor muscle.(3)The food of Ostrea rivularis Could had different carbon and nitrogen isotope features.Theδ13C values of Phytoplankton and Benthic-Macroalgae were: -19.93‰～-20.90‰,-13.43‰～-18.47‰,the later had more enrichmentδ13C values. That because they used different carbon when photosynthesis. So the Benthic-Macroalgae enriched 13C more easily. Different Macroalgae had differδ15N values, the ranged of values was 8.06‰～12.60‰,that maybe because they used different nitrogen. It was inferred that the nutrient source of Macroalgae in Zhanjiang Harbor were mainly from atmospheric and human-drived waste according to the comparision ofδ15N values among atmospheric and human-drived waste and man-made ferilizer. Sediment had different stable carbon and nitrogen isotopes on stations, and its isotopes values were dilution at all foods, relatively, theδ13 andδ15N values were:-24.57‰～-16.96‰,2.33‰～10.75‰。(4)It's quite different in proportion of the contribution between different food on the same site oyster. It's also different in proportion of the contribution between the same kinds of food on different oyster different sites. This may be related to oyster filter feeding choices and using food. In this study, large benthic algae is a major contributor to organic carbon in oyster. The average ratio of range in the four seasons is 55.38%～86.09%. Among the three kinds of benthic macro-algae, the largest is Enteromorpha clathratha. The largest and smallest contribution to the season of phytoplankton as Winter and Spring, the values were 23.8% and 7.8%. The contribution of sediment in four seasons( Spring, Summer, Autumn, Winter) respectively were 6.1%,18.4%,6.5% and 26.6%.(5)There were significantly diversity forδ13C andδ15N values of adductor muscle and ctenidia of Ostrea rivularis Gould in stations, but seasonal variation were not significantly. It has relation with the slow turnover rate of adductor muscle and ctenidia. This characteristic made adductor muscle and ctenidia can use to indicate the long-term pollutant, and the adductor muscle was better. Viscera mass showed the maximal variability forδ13C andδ15N values in four tissues, it showed significantly diversity in different stations and seasons. The characteristic make it can use to indicate the short-term or long-term pollutant, however, due to its complicated composition, so, should be make it further purified when using as a tracer. Theδ15N values of mantle tissue was similar as the viscera, they also had significantly diversity forδ13C andδ15N values in different stations and seasons,can use to indicate the short-term or long-term pollutant. So,in the preference of tracer, adductor muscle was suitable to using as long-term pollutant tracer, and mantle tissue was suited to indicate short-term pollutant.(6)Theδ13C andδ15N values in tissues of oyster has the same changed tend as contents of inorganic nitrogen( nitrite nitrogen, nitrate nitrogen, ammonia nitrogen and total inorganic nitrogen).Accossing the correlation analysis, the results were showed as: theδ15N values in adductor muscle can better respond to the contents of nitrite nitrogen, nitrate nitrogen, ammonia nitrogen and total inorganic nitrogen. The next were ctenidia and mantle tissue, also better respond to the contents of inorganic nitrogen besides ammonia nitrogen. The viscera mass was less, only to nitrate nitrogen. Hence, adductor muscle and ctenidia can use to indicate the long-term status of inorganic nitrogen, in the preference of adductor muscle. And mantle tissue was suitable to indicate the short-term status of nitrite nitrogen, nitrate nitrogen and total inorganic nitrogen, but indicate the short-term status of ammonia nitrogen need the next study.