Posts Tagged ‘climate change’

Save the Whale Poop

Tuesday, April 27th, 2010

by Hilary Maybaum

Once upon a 1980s time, I came across some fecal matter while searching for whales in the Pacific Ocean. It was a milky brown color with a greenish hue and quite flocculent. A humpback mother and calf had just left the vicinity of our boat. The calf had been breaching, and scientific consensus was that this was his or her poo.

Exciting stuff! In the decade or so that my colleagues had been studying the Hawaiian humpbacks, no one we knew had ever collected whale feces. Why was that, I wondered, and more pressingly, what can we learn from studying it? We already knew that adult whales don’t eat in their Hawaiian breeding grounds, except perhaps, opportunistically, but what about the calves? There are plenty of nursing whales in Hawaii, which must mean that the opportunity to collect calf poo exists, right?
Not to be caught off guard the next time we came across potential whale poop, I returned to our research headquarters that night and built a couple of whale pooper scoopers—one for each boat. Makeshift equipment, typical for a graduate student: long wooden spoons duct-taped to a couple of wide-mouthed plastic jars (caps stashed in the cooler along with a dash of formalin solution). From that day forward, all boat staff and volunteers were notified to be on the lookout for whale poop, and instructions on collecting said substance became part of our bi-weekly fa fa.

In the remaining years of my whale studies, we never did collect any whale poop. And it’s too bad, because now, it seems, whale poop is big news. Climate scientists now think that whale poop may play a major role in mitigating climate change by recycling iron in the ocean.

Remember a few years back, when seeding the ocean with iron seemed like a good idea to reduce the effects of global warming? It all started in 1988, around the same time I stopped trying to collect whale poop, when the late John Martin, former director of the Moss Landing Marine Laboratory, made a strange comment at an informal seminar at Woods Hole Oceanographic Institution. Martin said: “Give me half a tanker of iron, and I’ll give you an ice age.” What he meant, in his inimitable biogeochemical way, was that sprinkling iron dust in certain areas of the ocean’s surface could trigger massive algal blooms which, in turn, could potentially absorb enough heat-trapping carbon dioxide to cool the Earth’s atmosphere. That’s because algae, like land plants, take in carbon dioxide for use in photosynthesis, converting it into sugar and releasing oxygen as a by-product.

Mind you, whether artificial ocean iron fertilization would actually work is still a matter of debate. However, if enough whales keep pooping, we may not have to worry about it. Researchers at an organization called the Australian Antarctic Division, based in Tasmania, have found “huge amounts of iron in whale poo.” It’s a simple equation, really: the more whale poo, the more iron in the surface ocean, the more algal productivity, and the less carbon dioxide. Voila! A natural process with fewer side effects than artificial fertilization.

In retrospect, then, it’s probably a good thing that we never collected whale poop all those years ago. Who knows, we might have inadvertently sped up the effects of global warming.

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Acid oceans may alter marine mammal messaging

Sunday, December 27th, 2009

by Hilary L. Maybaum

I already knew that carbon dioxide affects the pH level of seawater, and that increased levels of dissolved CO2 could therefore cause the oceans to become more acidic by lowering seawater’s pH. While writing a book on climate change, I learned that ocean acidification is already happening in response to increased levels of atmospheric CO2; that is, the ocean can no longer buffer itself in response to global climate change with natural acid-base (chemical) reactions. Further, ocean acidification can, in turn, dissolve the tests (shells or exoskeletons) of crustaceans, corals, and other critters that depend on calcium carbonate for their bodily protection.

What’s news to me—and bad news at that—is how ocean acidification can also affect the transmission of underwater sound. According to recent articles in Science Daily and in Scientific American, scientists at my alma mater, SOEST at the University of Hawaii, and a scientist at my dream institute, California’s MBARI, found that ocean acidification lowers the ability of seawater to absorb low-frequency sound. In other words, increased CO2 levels make the ocean more transparent to sounds with frequencies up to about 5,000 Hz.

Dolphins, killer whales, humpback whales, blue whales, and scores of other marine mammals rely on the clear transmission of underwater sound to communicate with each other in the wild. They already deal with continuous low-frequency noise from waves and whitecaps. They also contend with constant low-frequency noise from anthropogenic (manmade) sources such as daily ocean traffic—ships, barges, and the like— as well as tourist and recreational activities. [I'm not even going to get into the cacaphony of naval testing of low-frequency sonar and explosives in this post.] I and others have found behavioral effects associated with increased noise levels and changes in existing underwater sounds. My colleagues have referred to some of these effects as whales “running away with their fins covering their earholes.” Of course, my esteemed colleagues exaggerate, but you get the idea.

Think of a beautiful house high on a hill, overlooking a long stretch of sandy, white beach. When you go to sleep, you are lulled by the gentle sounds of ocean waves hitting the shore. Now imagine that someone decides to put a superhighway between your house and the coast. You can no longer hear the ocean waves because of the traffic noise. That’s the kind of acoustical interference we are talking about. What happens when marine mammals can’t get their messages across because the cruise ships are louder, the jet skis are deafening, and breaking waves are giving them headaches? Will they run away, adapt, or die?

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