Hot Time, Summer in the City Bottom of My Feet Getting Oily and Icky

Hot Time, Summer in the City Bottom of My Feet Getting Oily and Icky

Santa Barbara offshore seeps pollute beaches from Los Angeles to Monterey.  The natural oil and gas seeps beneath the Santa Barbara Channel cause oil to drift to the ocean’s surface, producing a persistent oil slick that’s usually carried north and west by ocean currents, generally coming ashore between Santa Barbara and Gaviota. As the oil rises to the surface and floats, it coagulates and biodegrades into tar. This is the same tar that is found on the beaches along the Santa Barbara coastline – and on your feet!As a result of weather and ocean conditions, the greatest amount of tar appears on Santa Barbara beaches during the summer months.


To the dismay of local beach-goers, sticky globules of tar lap up onto our coastline every day. This tar is an annoyance to many of us and is often perceived to be a man-made pollutant. In fact, the tar results from the aforementioned natural seeps that have been spewing oil and gas into the Santa Barbara Channel for centuries. Our beaches lie along the second largest natural seep area in the world – a field with 2,100 active seeps.


You are right to be worried about impacts of the oil that’s on your feet. But you only come in contact with oil seeps in a peripheral way. The creatures that live in the marine environment are exposed continually, and it’s important to understand how the seeps impact these species that are so impact our lives – and are so important to our ecosystem.


It is important to note that much of our knowledge of specific impacts of oil on marine and coastal species comes from studies on oil spill impacts. We need to emphasize that the oil that is seeping naturally is crude oil – no different from the oil that spilled in Santa Barbara’s harbor in 1969. The seep oil comes from the same oil-bearing formations. Each year the beaches of Santa Barbara County are impacted by a quantity of oil equivalent to that 1969 spill –and that quantity is released through seepage.

Our coastal waters are home to rich and diverse marine environments.  Point Conception is often identified as the transition point between two biogeograhic provinces: the colder Oregonian Province and the warmer California Province. Because of the confluence of these two bioregions, the areas offshore Santa Barbara support a great diversity of marine species, many of which are extremely rare and afforded special protection under federal and state law.  These include over 195 species of birds that use the open water, shore, or island habitats in the area; at least 33 species of cetaceans (whales and dolphins); 7 species of pinnipeds (seals and sea lions); and the southern sea otter.  All can be negatively impacted by encounters with oil released from seeps. Oil that has entered the water from seeps, in general, can have a smothering effect on marine life, fouling feathers and fur. It is a toxic poison that birds and mammals often ingest while trying to clean themselves. Fish absorb it through direct contact and through their gills.


Even when the oil does not kill, it can have more subtle and long-lasting negative effects. For example, it can damage fish eggs, larva and young – wiping out generations. It also can bio-accumulate up through the food chain as predators (including humans) eat numbers of fish that have sub-lethal amounts of oil stored in their bodies. Although seep-related fatalities are rare, low-level hydrocarbon exposure might be a significant stressor for animals living in seep areas. Systemic poisoning from chronic exposure could weaken the animals, making them more vulnerable to disease (SB County Energy Division).


Oil can be especially harmful to our coastal birds and seabirds—particularly diving birds that must get their nourishment from the water. With birds such as common loons and western grebes, the oil interferes with the birds’ ability to maintain their body temperature, often resulting in death from hypothermia by reducing or destroying the insulation and waterproofing properties of their feathers. Oiled birds also become easy prey, as their feathers being matted by oil make them less able to fly away. They also lose body weight as their metabolism tries to combat low body temperature. Seep oil has a far greater impact on bird populations that are aggregated during breeding or migration than those that are widely dispersed at sea. It is likely that the cumulative effect of numerous “small” spills and chronic pollution, such as through constant offshore oil seepage, has had a greater effect on seabird populations than the rarer large spills (Oil in the Sea 2003). The Santa Barbara Wildlife Care Network each year cleans approximately 50 birds that have been oiled by natural seeps. But higher seep flow volumes can impact much larger numbers. The International Bird Rescue Research Center, in March 2012, reported the oiling of 97 common murres – from one high flow event that was traced to the Santa Barbara seeps. As their blog stated, “Unlike the birds we hear about during high profile oil spills, these birds are being oiled by a natural oil seep along the Southern California coast, so public awareness is much more limited. The danger, however, to the birds is identical.”


Marine Mammals

Recent studies on possible effects of oil on marine mammals have focused on the behavioral effects, thermal effects, and physiological effects due to contact, inhalation, and ingestion of oil. Oil slicks on the water’s surface are particularly dangerous to fur bearing marine mammals. The lethargic behavior of oiled seals following the Exxon Valdez oil spill was not attributed to blanketing effects from a catastrophic spill, but rather to brain damage from inhalation of volatile fumes, since they breathe just above the water’s surface. This was suggested as being especially threatening with less weathered oil on the calm waters and on haulouts early in the spill (Parks Canada 1999).  The seeps at Coal Oil Point provide a constant supply of fresh oil and associated volatile fumes in an area frequented by harbor seal and other pinnipeds.


Fur-Bearing Marine Mammals

Fur-bearing marine mammals such as sea otters and fur seals are especially vulnerable to the effects of crude oil.
Fur seal pups drown if oil sticks to their flippers or to their bodies, and when it sticks to their fur it reduces or destroys the insulation of their wooly fur (called lanugo) and causes hypothermia. Adult fur seals have blubber and would not suffer from hypothermia if oiled. In California, the sea otter population was listed as “threatened” species. Sea otters are particularly vulnerable to oiling. Oil may compromise a sea otter’s fur coat thus hampering its ability to keep warm.  Sea otters may also groom and ingest oil trapped in their fur or inhale volatile components of freshly released oil, as from an ongoing seep.  Whether from ingestion or inhalation, otters exposed to oil may become sick and die (University of Alaska 1995). Different from whales, sea lions, and most seals, the sea otters do not have a layer of blubber to protect them from cold water. Instead, these marine mammals rely entirely on their very dense fur (300,000 hairs per square inch) for insulation. Oil compromises this protective coat and even a small oiled area of their fur can cause hypothermia and potentially death of the sea otter.


Gray whales:

Twice each year, from December to May, the population of the California, or eastern North Pacific, gray whale passes through southern California on its migration between breeding and calving lagoons in Mexico and summer feeding grounds off Alaska. During this journey, most gray whales stay close to the coastline and pass through the Santa Barbara Channel and the Santa Maria Basin—areas where most of southern California’s natural oil and natural gas seeps are located. Studies have shown that cetacean skin is nearly impenetrable to even the highly volatile components in oil. However, the toxic, volatile fractions in fresh crude oils could irritate and damage cetacean soft tissues, such as the mucous membranes of the eyes and airways and the effects could be as severe as death in extreme cases. Oil could also adhere to the fringed baleen plates that gray whales use to filter their food, blocking the flow of water and interfering with feeding. Gray whales are among the most vulnerable of the baleen whales to effects of ingesting oil-contaminated prey or bottom sediments since they are mainly bottom feeders.


While we don’t ingest oil, it can get on our skin – and people who spend time in the water definitely start to feel impacts that are similar to those experienced by the creatures that live in it.  Stay tuned to our next August blog to see how seeps could impact you!




    1. Straughan, D., 1976, “Sublethal effects of natural chronic exposure to petroleum in the marine environment,” American Petroleum Institute Publication No. 4280.


    1. University of Alaska 1995.  Emergency Care and Rehabilitation of Sea Otters: A Guide for Oil Spills Involving Fur Bearing Animals


    1. Loughlin, T.R. (ed.), 1994, Marine Mammals and the Exxon Valdez, Academic Press, San Diego


    1. Geraci, J.R., and D.J. St. Aubin, 1987. Effects of offshore oil and gas development on marine mammals and turtles, in Long-Term Environmental Effects of Offshore Oil and Gas Development, D.F. Boesch and N.N. Rabalais, eds., Elsevier Applied Science, London.


    1. Hunt, G.L. Jr., 1987, Offshore oil development and seabirds: The present status of knowledge and long-term research needs, in Long-Term Environmental Effects of Offshore Oil and Gas Development, D.F. Boesch and N.N. Rabalais, eds., Elsevier Applied Science, London.


    1. International Bird Rescue Research Center 2012.


    1. Minerals Management Service (MMS) 2008


  1. County of Santa Barbara 2002.  Natural Oil Seeps and Oil Spills. March 2002. County of Santa Barbara, Planning and Development, Energy Division.


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