Marine organisms live in a wide range of habitats and environments. These can be cold Antarctic waters high in nutrients to nutrient-poor tropical oceans to the deep sea. This is possible because marine organisms have had millions of years to evolve the necessary adaptations for these environments. The problem with climate change and pollution is that big changes are happening to the oceans in very short periods of time.
One example is mercury, a toxic compound that is found naturally in the atmosphere and oceans and is released from the earth's crust by volcanoes. Although marine organisms have had a long time to adapt to mercury, the amount of it in the atmosphere has tripled in just the last 100 years, most coming from our use of coal to produce energy. Not surprisingly, we are already starting to see marine mammals with very high levels of mercury in their bodies. These high levels could be extremely harmful to them.
Another problem with pollution is that we are presenting marine organisms with challenges that they have never seen before and have not adapted mechanisms to deal with. For instance, we inadvertently wash many drugs down the drain that introduce hormone-like chemicals into the oceans. These hormone mimics can confuse the cellular systems that control fish growth and interfere with their ability to reproduce as adults.
Examples like those or the recent Gulf of Mexico oil leak make it clear how pollution and climate change are having an adverse impact on our oceans. If and how some marine organisms might be able to adapt to new threats we generate remains to be seen.
-- Amro Hamdoun, assistant professor of biology, Marine Biology Research Division
To learn more about Scripps research during the Gulf of Mexico oil leak, read our story “Lessons from Deepwater,” http://explorations.ucsd.edu/Features/2010/Lessons_Deepwater