Abstract:

Testing the effect WAF (water accommodated fraction) on TEP (transparent exopolymers) and CSP (Coomassie stained particles). Samples were collected as a time series in the Control, WAF, and the WAF silicon tube treatment. Qualitative, but not quantitative samples were also collected in the sea surface microlayer and from the sunken marine snow.

Suggested Citation:

Uta Passow. 2017. GOM open ocean (GOMOO): Production of TEP (transparent exopolymers) and CSP (Coomassie stained particles) as a function of oil. Distributed by: GRIIDC, Harte Research Institute, Texas A&M University–Corpus Christi. doi:10.7266/N7ST7N61

Purpose:

This mesocosm experiment investigated the response of an open ocean plankton community from the Gulf of Mexico to dispersed oil in comparison to conditions without oil. Specifically, the effect of oil addition for the production of transparent exopolymer particles (TEP) and CSP (coomassie stainable particles) was tested. TEP, that are rich in polysaccharides, are central for the formation of marine snow. The role of CSP, which are protein-rich is less clear.

Data Parameters and Units:

Timepoint (day) SSW = surrounding seawater, sample does not include marine snow; Avg = average (of three replicate mesocosms); Stdev = standard deviation; TEP = Transparent Exopolymer Particles (ug GXeq/L); CSP = Coomassie Blue Particles (mg BSAeq/L); GXeq = Gum Xanthan equivalent; BSA eq = Bovine serum albumin equivalent; Control = Control treatment containing seawater and plankton community; WAF = Water accommodated fraction treatment, containing WAF made from the seawater (see methods) and plankton community; DL = at or below detection limit

Methods:

In order to create an environment for controlled testing of TEP and CSP formation six 112 L capacity glass tanks (40x40x72 cm3) were used as mesocosms. Three replicate tanks were considered controls and three oil treatments, produced with a water accommodated fraction of oil (WAF; WAF-treatments). The WAF was produced using 130 liter baffled recirculating tanks (BRT) and Macondo Surrogate oil. Seawater was collected from 2 m depths 0.25 miles from buoy N in the Flower Garden area (27° 53.4180'N 94° 2.2020'W) in the Gulf of Mexico 8 July 2016 (salinity 30.8). This water was blue and clear. The three Control tanks were filled directly with seawater from the storage tank (90 liters each). WAF was prepared by mixing 25 ml (5 ml ~ every 30 min for 2.5 hrs.) of Macondo Surrogate oil into 130 L of seawater then mixing for 12-24 hrs. The WAF was then introduced into the WAF mesocosm tanks (90 L). Macro-nutrients were added to each tank (F/8 levels). Plankton (≥63 µm), which had been collected at the same side as the seawater using a net and the pump were also added. immediately prior to starting the experiments. Banks of lights were placed behind each of the glass tanks and a 16:8 light dark cycle used. Samples were drawn through a 5 cm diameter Teflon faucet, positioned 10 cm from the bottom of each tank. Samples were collected every 12-24 hrs. up to 96 hrs. TEP concentrations were determined in triplicate twice daily (every 12 hours) using the colorimetric method and are expressed in Gum Xanthan equivalents (GXeq.) (Passow and Alldredge, 1995). CSP was determined once daily (every 24 hrs.) using the colorimetric method (Cisternas-Novoa et al. 2015).

Error Analysis:

Coefficient of variation (standard deviation / average) were calculated from the triplicate TEP analysis to identify problems. Averages and standard deviations were calculated from the three replicate mesocosms of each treatment.

Provenance and Historical References:

Cisternas Novoa, C., C. Lee, A. Engel (2015). Transparent exopolymer particles (TEP) and Coomassie stainable particles (CSP): Differences between their origin and vertical distributions in the ocean. Marine Chemistry, 175: 56-71, doi.org/10.1016/j.marchem.2015.03.009. Passow, U., Alldredge, A.L., 1995. A dye-binding assay for the spectrophotometric measurement of transparent exopolymer particles (TEP). Limnology and Oceanography 40 (7), 1326-1335.

Individual Files: