Nitrogen stable isotope ratios have successfully been applied in the study of trophic linkages, as well as of human impacts in aquatic ecosystems. Anthropogenic wastewater input typically elevates d N values in dissolved inorganic nitrogen and this N enrichment subsequently propagates throughout the food chain. Bivalve mollusks are of interest for studies of this human in uence since they are primary consumers and are known to trace environmen have, for example, been found to correlate with the fraction of residential development in watersheds around lakes and salt an ecosystem, before anthropogenic nitrogen input, d N records need to be extended into the past. Bivalve shells can be useful for this, since they are often abundant in archaeological deposits as well as historic museum collec tions.

A predictable relationship has been demonstrated between the d N values of shell organic matter and soft tal d N variability. The d N values of their soft tissues marshes. To determine the undisturbed d N values in tissues and d N values of this organic matrix indeed trace anthropogenic in uences. animals. Syva??ranta et al. found that neither formalin nor ethanol had a significant LY294002 effect on d N values of preserved zooplankton and macroinvertebrates. However, in fish muscle, enrichments of 0. 5 to 1. 4% have been found after fixation in formalin and subsequent preservation in etha studies, but generally preservation effects on tissue d N found that ethanol preservation lowered d N values of the soft tissues of the freshwater bivalve Corbicula uminea by 0. 39% after 6 months.

Similarly, in the freshwater mussel Amblema plicata, ethanol preservation for MEK Inhibitors 1 year caused a contrast, some other workers found higher d N values for liquid preserved mollusk tissue samples in comparison to frozen or dried samples. Ethanol preservation for 12 weeks resulted in a non significant enrichment in octopus and vulgata, tissue d N values increased up to 1. 1% and 1. 0%, respectively, after treatment with formalin for 2 days and ethanol for 6 24 months. In summary, wet preserved specimens typically exhibit a small enrichment in nol. Results on mollusks differ among values are small in short term studies. Sarakinos et al. change of _0. 23% in tissue d N values. In Littorinid tissues. In Mytilus galloprovincialis and Patella N, but this effect is variable between studies.

We report herein the evaluation of the method of simple combustion without acidification by testing the in uence of CaCO 3 content on d N values of different mixtures of acetanilide and synthetic pure CaCO 3. We also investigate the fractionation between tissue and shell organic matrix in the bivalve Mytilus edulis. Finally, we examine the effects of long term ethanol preser Neuronal Signaling vation on d N values of bivalve shell organic matrix. For the comparison of d N values of mantle tissue and shell organic matrix, three specimens of the blue mussel Mytilus edulis were collected in 2002 in Knokke, Belgium investigation of the long term effect of ethanol preservation, six shells from the Royal Belgian Institute of Natural Sciences collected at Dudzele on 27 March 1936 were selected.

DNA Damage Three individuals were stored dry and three individuals were preserved in ethanol along with whole soft tissues. In addition, dry stored shells from three individuals collected at a nearby site at Lissewege on 22 November 1938 were obtained from the same museum and one shell, collected on 3 June 1935 at Knokke, was obtained from the Dutch National Museum of Natural History, Naturalis. All shell samples were rinsed with deionized water and left to dry. The periostracum was completely removed with a Dremel abrasive buff. Calcite samples were taken from the outside of the shell with a hand drill, the inner aragonite layer was avoided. Between 10 and 20 mg of calcite powder was collected, covering an area of at least 1 year of the most recent growth.

The mantles from the ethanol preserved specimens were dissected, rinsed NSCLC with Milli Q grade water and dried overnight at 608C and pooled. An aliquot of the ethanol these specimens were preserved in. For the Various sample preparation techniques have been used to analyze d N values of skeletal organic matter, such as acidification or simple combustion of whole skeletal material. These methods are also used in analysis of organic matter. Animal soft tissue samples contain varying amounts of CaCO 3, which will introduce a bias in d C measurements. Therefore, samples are generally treated with an HCl solution before analysis. However, the acidification process in itself may in uence d N values, although some authors found no effect of typically avoid acidification of samples for d N analysis and will run one set of non acidified samples for d N and one CaCO 3 on d N analysis, then avoiding acidification would be the method of choice for d N analysis of shell organic matter.