Check out the full story detailing how much plastic these gentle giants actually consume. A single Sperm Whale has been recorded with over 400 hundred pounds of plastic refuse in its stomach! 10/21/2013 The tale of dimethyl sulfide: A global climate regulator turned marine infochemicalRead NowI must admit, I took the idea for the title of this post from a recently-published paper by my PhD advisor (Nevitt 2011. Integ. & Comp. Biol. 51:819-825). This post is about how a simple, plant-derived molecule influences global climate and mediates biotic interactions throughout the marine food web. The molecule in question is dimethyl sulfide (DMS) and it is so important that many scientists have dedicated their entire careers studying it in action. DMS consists of a single sulfur molecule stuck between two methyl (CH3) groups. Produced by marine and freshwater algae, DMS is a breakdown product of dimethylsulfoniopropionate (DMSP; an osmoregulatory compound) and forms when algal cells lyse. DMS has a very low boiling point, which means that once it’s formed in the water, it readily evaporates. For a long time, DMS was thought to be nothing more than a biological waste product of DMSP catabolism. That all changed in the late 1980s, when a paper was published in Nature titled: Oceanic Phytoplankton, Atmospheric Sulfur, Cloud Albedo and Climate (Charlson et al. 1987). That article has since been cited over 2,100 times according to the Web of Science. This paper was revolutionary because it suggested that DMS plays a significant role in global climate regulation. When DMS evaporates, it oxidizes to form sulfur dioxide, which is an important cloud-forming molecule. An increase in the amount of algae in the ocean would theoretically increase the concentration of DMS in the air and subsequently form more clouds. Clouds do a great job of reflecting incident solar radiation back into space. This increase in the earth’s reflectance (termed “albedo”) would lower global temperatures. The CLAW hypothesis, as this theory is now known, is an acronym for each of the authors’ last names of the original paper (Charlson et al. 1987). DMS wasn’t well known among zoologists until the mid-1990s when it was first suggested that procellariiform seabirds (i.e. petrels and their allies) use the scented compound to help locate biologically-productive regions to feed (Nevitt et al. 1995. Nature. 376:680-682). Since then, it has been shown that organisms as diverse as penguins, reef fish, seals, and whale sharks are attracted to DMS/P in foraging contexts. A biochemical that provides information to another organism is known as an infochemical. The concept that a plant-derived compound signals to attract predators has been known for decades in the plant-insect literature, but this idea is fairly new in the marine realm.
That is where my work comes in. In addition to studying plastic ingestion in procellariiform seabirds, I am also investigating the role these amazing birds play in a marine tritrophic interaction, mediated by the infochemical, DMS. From its humble beginnings as a mere biological waste product, DMS has turned into one of the most well-studied molecules on the planet. An interesting tale, indeed. Evolutionary traps make the cover on this month's Trends in Ecology & Evolution (Robertson et al. 2013). Apparently, the prominence of one of my research topics is trending upwards! Read the article here And check out Bruce Robertson's website if you want to learn more about evolutionary trap research. "Do we have the courage to face the realities of our time?" A fantastic trailer to a new documentary by Chris Jordan.
The stunning Laysan and Black-footed Albatross of Midway Island in the north Pacific face a serious threat that, as recently as 100 years ago, was unknown on the face of the earth... plastic. Plastics have permeated our everyday lives and become so ubiquitous (as I type this post on a plastic keyboard, navigate around the page with a plastic mouse, and sip soda from a 20oz plastic bottle) that we often forget how detrimental plastics can be once discarded. This short video is shows the grim reality of the "plastic age." My research focuses on why these beautiful creatures consume so much plastic in the first place. Does it look like food? Does it taste like food? Are they consuming fish/squid that have previously eaten plastic? Are they consuming plastic incidentally or purposefully? What steps can we take as a society to mitigate this problem? These are all questions I ask myself as both a conservation biologist and a concerned citizen. Many cities in California have now banned single use plastic bags. Indeed, this is a good start, but intelligently designed research asking the right questions can also help out. Stay tuned to my (new) blog as I post updates on my research progress and explore the world of plastic ingestion in marine biota. Additionally, I will be posting links to scientific papers that delve into the cutting-edge research in this field. Awesome study (Amo et al. 2013) by a couple very famous ecologists, namely Marcel Visser and Marcel Dicke, demonstrating that terrestrial songbirds use induced plant volatiles to locate their herbivorous insect prey. Not too long ago, it was thought that most passerine birds did not have a sense of smell. Read more here To my knowledge, this is the first study to link DMS behavioral responsiveness to diet, with work done on Chinstrap Penguins (Amo et al. 2013). Cool foundational work for the first chapter of my thesis! Read more here |
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AuthorMatthew Savoca holds a PhD in Ecology from the University of California, Davis. His research interests include sensory behavioral ecology, marine conservation biology, and seabird ecology. Categories
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December 2021
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