The “Butterfly Effect’ and Inter-Connectedness of Marine Life
Sea stars (Pisaster ochraceous) are predators that can control local population abundance within rocky intertidal communities by consuming the dominant mussel (Mytilus californianus). (Dr. Tarik C. Gouhier)
Explaining and understanding life cycles is on many people’s minds in spring, and McGill Biologist Dr. Frédéric Guichard is no exception – in fact, he’s made a fascinating discovery relating to the life, death, reproduction and communication … of mussels. Guichard says marine life can communicate over thousands of kilometres, calling into question current fishery management and marine preservation practices. “If I kill mussels in San Diego, it will have an impact in Seattle. We now know that populations are connected,” he said.
Using mathematical modeling and data from natural populations, Guichard and his colleagues, Dr. Tarik Gouhier and Dr. Bruce A. Menge at Oregon State University, found a phenomenon similar to the “butterfly effect,” whereby the actions of one individual can cause a series of chain reactions. Mussel populations communicate by actions such as releasing larvae or dying. “Current practices are based on the knowledge that a mussel can travel no further than 100 km in its lifespan, so efforts are focused on local areas in the belief that we can control local populations,” Guichard explains. “But this ‘fence approach’ only looks at the life history of an animal, which isn’t enough to predict how it will affect its environment and other marine life. (more…)
Humans “Damaging the Oceans”
Dr Andrew Brierley of St Andrews University, Scotland aboard the RRS James Cook on its first ECOMAR cruise to the mid-Atlantic Ridge.
Mounting evidence that human activity is changing the world’s oceans in profound and damaging ways is outlined in a new scientific discussion paper released today.
Man-made carbon emissions “are affecting marine biological processes from genes to ecosystems over scales from rock pools to ocean basins, impacting ecosystem services and threatening human food security,” the study by Professor Mike Kingsford of the ARC Centre of Excellence for Coral Reef Studies and James Cook University and colleague Dr Andrew Brierley of St Andrews University, Scotland, warns.
Their review, published in the latest issue of the journal Current Biology, says that rates of physical change in the oceans are unprecedented in some cases, and change in ocean life is likely to be equally quick.
These include changes in the areas fish and other sea species can inhabit, invasions, extinctions and major shifts in marine ecosystems. (more…)
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