Analytical measurements: Time series of nutrients in MICROX, a mesocosm to quantify microbial oxidation and degradation of oil

This experiment was conducted to investigate how nutrients change with time. Eighteen 110L capacity glass mesocosm tanks were filled with Gulf of Mexico seawater collected 8 km offshore south of Galveston (TX) that had been pre-treated with a charcoal filter to remove large particles and debris. Plankton (≥63 µm) were collected using a net and transferred into polycarbonate bottles after being pre-filtered (115 um) to remove zooplankton, jellyfish and debris. The tanks were amended with WAF (water accommodated fraction) and the DCEWAF (diluted chemically enhanced water accommodated fraction) to a target concentration of 2 mg/L. Concentrated plankton mass was introduced to each of the tanks immediately prior to starting the experiments. A 12:12 light/dark cycle employed. Treatments included controls (2), WAF (8) and DCEWAF (8). One mesocosm was sacrificed at each sampling point. Controls were sampled on Day 0 and Day 12. For WAF and DCEWAF, sampling was more frequent at the start and less frequent with time, such that sampling was done on 0, 0.5, 2, 3, 6, 8, and 12. Nutrients were determined on an autoanalyzer.