To the chagrin of many, oil spills in our oceans are more ubiquitous than we think. A seaborne resource, oil spills are often caused by accidents involving refineries, tankers and storage facilities. Amongst others, these accidents are the result of human error, faulty equipment, illegal dumpers, terrorism and natural disasters. However, did you know that there are different types of oil spills? While surface oil spills are easily identifiable (oil floats on water) and leave oil stains and vapours released by the spilled oil, underground oil spills are far more difficult to identify and are far more insidious. This is because underground oil spills have a higher propensity of contaminating sediments and groundwater.

Oil spills can also seriously injure animals. (I’m pretty sure all of you have seen images of sea otters and birds laden with oil). However, apart from trapping these animals, oil weakens the insulating and water-repelling abilities of mammals and birds respectively when exposed to harsh elements. Likewise, oil can also cause irretrievable harm to the immune systems on bottlenose dolphins, weakening it to a state where they become extremely vulnerable to infections and disease.

But these ramifications do not stop here. Oil spills have long-standing catastrophic implications for the environment as evident in the wake of the Deepwater Horizon disaster. Eight years on, and oil levels in the sediments in the surrounding coastlines were 10 times higher as compared to pre-accident levels. According to Edmond (2021), oil droplets still continued to infiltrate the seabed a year after the accident ended, impacting sedimentation rates and inevitably harming the habitats and food source for many marine creatures.

Another cause of concern is the role that oil spill impacts play in accelerating the growth of harmful algal blooms (HAB). Eklund, Knapp, Sandifer and Colwell (2019) reveals how a causation was found in a study on oil spill impacts and the Florida red tide organism, Karenia brevis. Contaminants leaked from oil spills were discovered to have caused trophic cascades, contributing to the growth of algal blooms. Specifically, Eklund et al. (2019) highlight how the presence of anthropogenic impacts including oil spills resulted in growths in HAB formation and the aerolisation of HAB toxins even in environments with lowered phytoplankton grazing rates and reduced zooplankton populations.

This has severe repercussions for the human population as the release of toxic compounds by Karenia brevis not only harms marine animals and causes fish kills but threatens human health. Walsh et al. (2017) indicates how the widespread growth of aerosolised HAB toxins contributed to chronic pulmonary attacks and 15% of worldwide asthma events in 2004, but also affected another 45 million people. Moreover, it was posited that 40% of mercury poisoning did not originate from seafood consumption, but rather HAB aerosol contamination (Walsh et al., 2017 as cited in Eklund et. al, 2019). Therefore, these estimates not only suggest that HABs pose serious health threats to human health, but that oil spills triggered a trophic cascade that led to the aforementioned health risks.

References

Eklund, R., Knapp, L., Sandifer, P. and Colwell, R., 2019. Oil Spills and Human Health: Contributions of the Gulf of Mexico Research Initiative. GeoHealth, 3(12), pp.391-406.