Abstract:

Marine snow aggregates were collected from the mesocosm tanks. The concentrations of 16 EPA priority polycyclic aromatic hydrocarbons (PAHs) namely; Naphthalene (Nap), Acenaphthylene (Acy), Acenaphthene (Ace), Fluorene (Flu), Phenanthrene (Phe), Anthracene (Ant), Fluoranthene (Flt), Pyrene (Pyr), Benzo[a]anthracene(BaA), Chrysene (Chr), Benz[b]fluranthene (BbF), Benz[k] fluoranthene (BkF), Benzo[a]pyrene (BaP), Indeno[1,2,3-cd]pyrene (Ind), Dibenzo[a,h]anthracene (Dba), and Benz[g,h,i]perylene (BghiP), were determined.

Suggested Citation:

Hernando Bacosa. 2019. Concentrations of polycyclic aromatic hydrocarbons (PAHs) in marine snow aggregates. Distributed by: GRIIDC, Harte Research Institute, Texas A&M University–Corpus Christi. doi:10.7266/5P8B7NWV

Publications:

Bacosa, H. P., Kamalanathan, M., Cullen, J., Shi, D., Xu, C., Schwehr, K. A., … Quigg, A. (2020). Marine Snow Aggregates are Enriched in Polycyclic Aromatic Hydrocarbons (PAHs) in Oil Contaminated Waters: Insights from a Mesocosm Study. Journal of Marine Science and Engineering, 8(10), 781. doi:10.3390/jmse8100781

Purpose:

To determine the concentrations and distributions of 16 EPA priority polycyclic aromatic hydrocarbons (PAHs) in marine snow aggregates during mesocosm experiments.

Data Parameters and Units:

All data are expressed as ng/L (ng PAH compound per dry mass of aggregates). Control- Seawater only WAF- Water accommodated fraction DCEWAF- Diluted chemically enhanced water accommodated fraction 4 d - 4 days 16 d- 16 days A, B, C indicates replicates

Methods:

Marine snow aggregates that deposited at the bottom of the mesocosm tanks were collected at 4 d and 16 d. Freeze-dried aggregates were extracted for polycyclic aromatic hydrocarbon (PAH) using hexane/ethyl acetate. Extracts were concentrated and PAHs were analyzed using gas chromatography-mass spectrometry (GC-MS). Mesocosm experiments were performed with Gulf of Mexico seawater collected 8 km offshore south of Galveston (TX) and were amended with microbial concentrate. Three treatments (Control, WAF and DCEWAF) were prepared in triplicate. Control tanks were filled with seawater. Water accommodated fraction (WAF) of oil was prepared by mixing 25 mL (5 ml ~ every 30 min for 2.5 hrs) of Macondo surrogate oil into 130 L of seawater. Mixing ended 24 hrs. after the initial oil addition (Knap et al. 1986). The WAF was then introduced into the WAF mesocosm tanks and filled to 87 L and mixed. From these WAF tanks, 6 L was removed for other experiments and analyses (2 L dark/light, 4 L hydrocarbon analyses). In order to make chemically enhanced water accommodated fraction (CEWAF), Corexit was mixed with oil in a ratio of 1:20. Diluted CEWAF (DCEWAF) was prepared by mixing 9 L of CEWAF with 78 L of the original seawater for a total volume of 87 L.

Instruments:

Gas chromatography-mass spectrometry (GC-MS).

Provenance and Historical References:

Knap, A. H., Burns, K. A., Dawson, R., Ehrhardt, M., & Palmork, K. H. (1986). Dissolved/dispersed hydrocarbons, tarballs and the surface microlayer: Experiences from an IOC/UNEP Workshop in Bermuda, December, 1984. Marine Pollution Bulletin, 17(7), 313–319. doi:10.1016/0025-326x(86)90217-1

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