Given the lack of detectable impact by PCBs, toxaphene, or PAHs on living fungal standing crops in impacted marshes and the positive impact on this parameter in urbanized marshes, the last year's effort will be concentrated either on determining whether complex organic pollutants are altered by the lignocellulolytic enzymes of saltmarsh-ascomycetes, or examining the nitrogen subsidy hypothesis for increased fungal standing crops in urbanized marshes. Work also will continue on manuscript preparation and submission. Gas Exchange Studies. Fieldwork during the third year of the study suggested that plant gas exchange measurements vary as a function of tidal stage and range. If true, successful use of gas exchange measurements as an environmental tool would require that variation due to tidal fluctuation be avoided in the sampling design or factored out in the analysis stage.
Preliminary results support both hypotheses.
Work in the final year of the grant will focus on data analysis and manuscript preparation. Crustacean Reproductive Potential Studies. Emphasis continues on counting and measuring the extensive set of samples collected from the Georgia and South Carolina sites. It is expected that these enumerations will be completed for all samples by June or July 2000. The remaining effort will be placed on statistical data analyses and preparation of manuscripts of publication in the peer-reviewed literature.