PW18 Field Biological Monitoring of Ecosystem Impairment
Exhibit Hall
8:00 AM - Wednesday
(PW278) Assessing freshwater aquatic ecosystem status using chitobiase activity.
Hanson, M.L.1, Lagadic, L.1, 1 INRA EQHC, Rennes, France
ABSTRACT- A new method to assess freshwater arthropod community health is presented. It integrates all arthropod communities into a single measure using the arthropod molting enzyme chitobiase, which is released into the aqueous environment during ecdysis. The inference is that arthropod populations, in terms of biomass, are therefore similar when chitoiase activity is similar. A sampling program was initiated on the Oir and Scorff rivers in western France. Initial results show consistent levels of standing chitobiase activity across the riversheds, with relatively low variation within both rivers and their tributaries on sampling dates. Similar patterns of chitobiase acitivity are observed between monthly sampling dates, with the lowest acitivty during the winter when most arthropods would be in diapause or a resting stage. Chitobiase levels in declined when inputs from wastewater treatment plants entered tributaries and rivers, implying that arthropods were impacted, perhaps through contaminants or habitat degradation, but this was not always the case. When compared with fish population data, those sections of the rivers with the highest levels of chitobiase acitivity, generally had the largest fish. Overall, this rapid and simple assay has potential in monitoring aquatic arthropod populations in the field, but extensive validation is required.
Key words: Arthropod community, Field assessment, Chitin synthesis