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Title: Exchange rates for carbon, nitrogen, and phosphorus in the Colorado River delta marshes. Final report

Technical Report ·
OSTI ID:6173686

This study was undertaken to determine nutrient exchange rates from the marshes in the Colorado River delta to adjacent waters. Portions of the marshes were collected based on the representation of major plant types in this system. The samples for the plexiglass reactors were taken in the field with these reactors and returned intact ready for experimentation to the laboratory. The laboratory studies consisted of placing these reactors under controlled light and temperature conditions to simulate seasonal conditions in the field, imposing a diurnal tidal regime on the reactors, and measuring nutrient concentrations in the influent and effluent of the reactors. Based on the difference between mass and flow of each nutrient into and out of the reactors, an exchange rate was calculated in units of kg ha/sup -1/ d/sup -1/ for each reactor. Based on the major plant types contained in each reactor, the data for each reactor were grouped by major plant type and described. Seasonal changes in exchange rates were plotted and discussed. The exchange rates for carbon, nitrogen, and phosphorus for the major plant types were found to be very similar to exchange rates measured previously for similar plant types in Lavaca, Nueces, and San Antonio Bays and the Trinity River delta. Biological activity appeared to dominate the processes which affected concentrations of carbon, nitrogen, and phosphorus. Attached algae appeared to dominate the macrophytes affecting changes in nutrient concentrations; however, it was not possible to measure the release of phosphorus by the macrophytes alone and to determine their contribution to the exchange rates.

Research Organization:
Texas Univ., Austin (USA). Center for Research in Water Resources
OSTI ID:
6173686
Report Number(s):
CRWR-153; ON: DE83901439
Country of Publication:
United States
Language:
English