Linking nitrogen and phosphorus uptake in streams to metabolism, ecosystem structure, and substrata type
Podzikowski, Laura Y.
MetadataShow full item record
Many previous studies have compared nutrient uptake rates to metabolism between multiple streams, while few have attempted to explain variations seen at the substrate level. In this study we examined the variations seen in the relationship between nutrient uptake and metabolism at both cobble and sand substrata in Augusta Creek. We utilized in situ benthic chambers to measured phosphate, nitrate, and ammonium uptake rates and compared them to heterotrophic respiration and gross primary production. We found that heterotrophic respiration positively related to nitrate, ammonium, and phosphate rates under ambient conditions at the sand sites. Gross primary production related positively to nitrate uptake at cobble sites, while heterotrophic respiration negatively related to nitrate at cobles sites. These data suggest that heterotrophic activity tended to dominate sand sites rich with particle organic material for microbial activity, as heterotrophic respiration correlated positively at these sites. While gross primary production correlated with nitrate uptake at cobble sites suggesting that autotrophic activity tended to dominate the algae rich cobble sites. These data help to shed further light on the complex relationship between nutrient uptake and metabolism and suggests the need for more site-specific studies, such as this one.