This final installment of our Ask Chloe series considers perhaps the most pressing question for dolphins and the rest of us: how will we fare in the face of global warming?
Alan A (60yrs old from Hawaii): Since dolphins breathe the same air we do, what impact, if any, does our air quality have on them?
One might expect air quality to affect a dolphin’s lungs, but there are not many studies addressing that issue. One event that shows how our activities affect the health of dolphin lungs was the BP oil spill. Dolphins breathe at the surface of the water, where it is easy to inhale oil from a spill such as the 2010 Deepwater Horizon spill. Dead dolphins that washed up along shorelines in the area of that spill had severe lesions in their lungs, unlike what is normally seen in wild dolphins. It is worth remembering, that presumably this was also very painful for them.
Our air quality also affects the ocean and its inhabitants in ways that are less obvious though extremely destructive. A highly insidious and pervasive problem with our current atmosphere is ocean acidification. Carbon dioxide in our atmosphere emitted from fossil fuels mixes with seawater to form carbonic acid in the ocean. This changes the pH of the water, making it more acidic. The acidity of our oceans has already increased by 30% in the last 250 years. And why is an acidic ocean a problem? The first victim of ocean acidity is coral, the small animals that use calcium carbonate to grow. In an acidic ocean, calcium carbonate is increasingly difficult for these animals to synthesize. This photo by my friend Orvil Clark, known on Instagram as @ogc77, shows what a healthy reef looks like.
An understanding of the food chain would lead us to hypothesize that less coral means less food for coral-eating fish and perhaps less food for bigger fish who eat smaller fish, and less food for the dolphins who eat those fish. Indirectly, our air quality may be starving dolphins via ocean acidification. Mercury from coal plants also gets into the ocean from the air and into the food chain. Once again, as you travel up the food chain, mercury accumulates to toxic levels by the time you reach dolphins. Baby dolphins can ingest mercury from their mother’s milk, resulting in increased infant mortality.
Ben D (NYC filmmaker): Can Dolphin’s survive Global Warming?
It’s hard to say whether dolphins can survive global warming, because it is difficult to fully estimate the ways in which global warming will impact dolphins. A diminished food source is one very likely issue that dolphins will face due to global warming. And remember that certain dolphin species such as spinners don’t seem to be highly resilient, as they have inflexible hunting and resting schedules and only eat very specific kinds of food. Loss of habitat due to increasingly warm waters could also challenge the resiliency of dolphins who need to rest in bays with white sandy bottoms. It’s also hard to estimate how dolphin reproductive success might be affected by global warming, or increased competition from expansion of other species that may thrive under warmer conditions. Global warming might also affect different dolphin species to different degrees. Bottlenose dolphins may be more resilient than spinners, but we would need more research to know for certain. The scariest thing about global warming is that it is happening at a rate too fast for scientists to fully grasp the effects before we have made them much worse. There is more information on the Dolphin Dance Project ‘Protect’ page about the impact of climate change on dolphins and what we can do about it.
For Further Thought…
Global warming is happening right now. Some species may thrive under these conditions, while others suffer. The prospects definitely do not look promising for humans or for dolphins. And when we consider the interconnectedness of all living things, global warming seems like a much more ominous and pervasive threat. An examination of how we contribute to this problem in our everyday lives is necessary, so we can begin to imagine what other options might be possible. All of our choices make a difference.