Petroleum hydrocarbons in the coastal environment Chris Reddy Dept. of Marine Chemistry and Geochemistry Woods Hole Oceanographic Institution, Woods Hole, MA

Petroleum hydrocarbons Petroleum is the biologic and geologic product of the “cooking and squeezing” of organic matter. It is composed of many compounds that can have different chemical, physical, and biological properties. Easiest to class as either refined or crude.

Boiling range °C Boiling range °F Wide-cut gas oils Residual oils Residuum Boiling range °C 200 600 400 800 1000 100 300 500 Straight-run gasoline Middle distillates Gasoline fractions Home heating oil Light gas oil Diesel Heavy gas lubes Kerosine Jet fuel max min

Percentage of molecular types Boiling point °C 100 200 300 400 500 600 100 normal alkanes 80 branched alkanes cycloalkanes 60 Percentage of molecular types 40 Percentage of molecular types aromatics 20 napthenoaromatics nitrogen, sulfur, and oxygen s 20 40 60 80 100 Gasoline Kerosene Diesel Heavy Lubricating Residuum fuel gas oil oil

Oil in the coastal zone Urban runofflarge input term “leaky faucet”, mainly used crankcase oil from cars and trucks, relatively low acute toxicity, impacts urban areas. Oil spillssmaller input, but is a dramatic event that may be from a wide range of products, toxicity can vary, pristine areas are vulnerable. Natural oil seepslarge input for long times scales, crude oil with varying toxicity.

Why study the fate of oil? Excellent opportunity to observe how ecosystems react to anthropogenic perturbations. Use knowledge for “engineered” clean-ups. Societal issues (human and animal health) Oil Pollution Act of 1990

Historical Spills Bouchard 65 Winsor Cove October 9, 1974 41,000 to 140,000 L of diesel fuel Florida Wild Harbor September 16, 1969 Spilled 700,000 L of diesel fuel

Florida spill: Background On September 16, 1969, the barge Florida ran aground on rocks near West Falmouth, MA. Over ~650,000 liters of diesel fuel spilled into the water column. Storm winds from the southwest drove the oil into Wild Harbor.

Florida spill (1969) Depth (cm) Concentration of total petroleum hydrocarbons (TPHs) (mg g-1 dry weight) 2 4 6 8 10 5 10 15 Depth (cm) 20 25 30 Wild Harbor August 2000 35 40

Atlantic marsh fiddler crab Uca pugnax

Burrowing depth Made plaster casts of burrows in areas of Wild Harbor and Great Sippewissett to compare burrow depths of oiled and non-oiled areas.

Peacock et al. 2005

RESULTS: Burrowing depth Oil Non-Oil Wild Harbor Great Sippewissett Mean depth (cm) ± s.e. 6.4 ± 0.6 16.2 ± 0.6 13.7 ± 3.2 T-test: shows STRONG significant difference between oiled and non-oiled burrow depths (<0.05)…P(T<=t) two-tail = 3.10557E-09 Total of 25 cores. Significant difference between oil and non-oil areas in Wild Harbor (t-test, p < 0.001)

Burrow casts Wild Harbor (oiled) Great Sippewissett

Florida spill (1969) Depth (cm) Concentration of total petroleum hydrocarbons (TPHs) (mg g-1 dry weight) 2 4 6 8 10 5 10 15 Depth (cm) 20 25 30 Wild Harbor August 2000 35 40

Santa Barbara Oil Seeps Releases >20,000 liters of petroleum daily. Seepage has been occurring for thousands of years. Sheens and tar balls along the Santa Barbara coastline are constant reminders of this natural process. Excellent opportunity to study the fate of petroleum in the marine environment. My group started work at this site a few months ago.

Seep stringer

Tarballs

Holly Platform product

Santa Barbara seep stringer

Santa Barbara beach tar

Santa Barbara beach tar

Summary Oil can have different properties and behave differently in the environment. Thanks to Helen White, Bob Nelson, Greg Slater, Jennifer Culbertson, Ivan Valiela, and Emily Peacock