Ocean Action Hub

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Ocean-Dwelling Species Are Disappearing Twice as Quickly as Land Animals

26 Apr 2019 - Researchers point toward marine creatures’ inability to adapt to changing water temperatures, lack of adequate shelter.

26 Apr 2019 - Researchers point toward marine creatures’ inability to adapt to changing water temperatures, lack of adequate shelter.

Marine animals are twice as vulnerable to climate change-driven habitat loss as their land-dwelling counterparts, a new survey published in the journal Nature finds.

As Mark Kaufman reports for Mashable, the analysis—centered on around 400 cold-blooded species, including fish, mollusks, crustaceans and lizards—suggests marine creatures are ill-equipped to adapt to rising temperatures and, unlike land animals that can seek shelter in the shade or a burrow, largely unable to escape the heat.

“You don't have anywhere to go,” Natalya Gallo, a marine ecologist at the Scripps Institution of Oceanography who was not involved in the study, tells Kaufman. “Maybe you can hide under a kelp leaf, but the entire water around you has warmed.”

Speaking with National Geographic’s Christina Nunez, lead author Malin Pinsky, an ecologist and evolutionary biologist at Rutgers University in New Jersey, further explains that ocean dwellers “live in an environment that, historically, hasn’t changed temperature all that much.”

Given that cold-blooded creatures rely on their surroundings to regulate body temperature, relatively stable marine ecosystems have actually made their inhabitants more susceptible to significant temperature changes. And while ocean temperatures are still much lower than those on land, as Anthony J. Richardson and David S. Schoeman point out in an accompanying Nature News and Views piece, marine heat waves, increased carbon dioxide pollution and other products of global warming are driving Earth’s oceans to higher temperatures than ever before.

To assess the threat posed by warming waters, Pinsky and her colleagues calculated “thermal safety margins” for 318 terrestrial and 88 marine animals. According to Motherboard’s Becky Ferreira, this measure represents the difference between a species’ upper heat tolerance and its body temperature at both full heat exposure and in “thermal refuge,” or cooled down sanctuaries ranging from shady forests to the depths of the ocean.

The team found that safety margins were slimmest for ocean dwellers living near the equator and land dwellers living near the midlatitudes. Crucially, Nunez writes, the data revealed that more than half of marine species at the higher end of their safety margins had disappeared from their historical habitats—a phenomenon known as local extinction—due to warming. Comparatively, around a quarter of land animals had abandoned their homes in favor of cooler environments.

CONTINUE READING: https://www.smithsonianmag.com/smart-news/ocean-dwelling-species-are-disappearing-twice-quickly-land-animals-180972040/

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Human Pollution May Be Fertilizing The Oceans. That’s Not a Good Thing - Smithsonian.com

2 Mar 2017 - Scientists now understand how the carbon and methane emissions from our cars, livestock and electricity use 

2 Mar 2017 - Scientists now understand how the carbon and methane emissions from our cars, livestock and electricity use are helping drive dramatic shifts in our climate through their contribution to the greenhouse effect. But they’re just beginning to untangle the effects of some of the other pollutants we produce. For instance, iron emissions from coal burning and steel smelting could actually be helping the oceans thrive and suck up more atmospheric carbon, according to new research.

If that sounds like a good thing, it isn’t. When we reduce our levels of iron oxide emissions—which we ultimately have to, to protect human and animals from inflammation and other adverse health effects—it will necessitate an even more drastic reduction in pollution to avoid the effects of climate change, the researchers warn.

Iron is a vital nutrient for nearly all living things. Humans need it to make new blood cells, while many plants need it to perform photosynthesis. However, iron is relatively rare in the open ocean, since it mainly comes in the form of soil particles blown from the land. For the trillions of phytoplankton in Earth's oceans, iron is a "limiting nutrient," meaning the available amount of it is a natural check on these creatures' population size. (To prove this, scientists in the early 1990s dumped iron across a 64 square kilometer region of the open ocean and quickly observed a doubling in the amount of phytoplankton biomass.)

Some scientists have proposed taking advantage of this fact through geoengineering, or deliberately intervening in the climate system using technology. Much like forests on land, phytoplankton in the ocean serve as "carbon sinks" because they take up carbon dioxide and then take that carbon with them into the deep ocean when they die. Therefore, adding more iron to the seas could potentially make these sinks even more potent at sucking up the carbon humans have dumped into the atmosphere, these proponents reason.

But the new research suggests that humans are already—albeit inadvertently—geoengineering this process, according to a study published today in the journal Science Advances.

Despite its promises to halt the growth of its carbon emissions by 2030, China remains the world's largest producer and burner of coal and the largest manufacturer of steel. Along with carbon, steel smelting and coal burning release particles of iron that can easily be carried away by the wind. Scientists have speculated for years that all those emissions could be fertilizing the oceans with extra iron, thus driving phytoplankton population growth, says Zongbo Shi, an environmental scientist at England's University of Birmingham. CONTINUE READING: http://www.smithsonianmag.com/science-nature/human-pollution-may-be-fertilizing-oceans-not-good-180962346/

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