Ocean Acidification Causing Coral Reefs to Be Less Resilient to Climate Change
Ocean acidification (OA) occurs when carbon dioxide from the atmosphere is absorbed by seawater, resulting in a chemical reaction that reduces pH and calcium carbonate levels vital for the growth and repair of calcifying organisms like coral, explains the National Oceanic and Atmospheric Association. Publishing their work in Nature Climate Change, researchers examined four species of coral and two types of calcifying algae over the course of the year in order to determine how they might bounce back from stressful conditions.
"We found that corals and coralline algae weren't able to acclimatize to ocean acidification," said study author Malcolm McCulloch, adding that that the effects were rapid and persistent.
At least one-quarter of carbon dioxide in the atmosphere from coal, oil and gas dissolves in the ocean, according to the Smithsonian Institute. Changes in the ocean's chemistry since the Industrial Revolution have been recorded at an unprecedented rate. In the last two centuries alone, ocean water has become 30 percent more acidic — not even natural buffering can keep up.
Because seawater contains high levels of dissolved substances, Woods Hole Oceanic Institute notes that ocean waters have a slightly alkaline, or basic, pH of around 8.2. As more carbon builds up in the atmosphere, we see higher levels being absorbed in seawater to form carbonic acid, which breaks down to become more acidic as the pH level drops. Calcifying organisms like coral grow by adding calcium carbonate from the seawater to their shells or skeletons, but the researchers note that some species are disproportionately affected in their ability to repair or grow as these levels drop.
"The results also confirm that Ocean acidification could have repercussions on the competition between species which could, in turn, affect the ecological function of reefs," said lead author Steeve Comeau. In their findings, two of the species were found to be resistant to OA from the start of the experiment while two others were too sensitive to acclimate. Those species that were able to adjust have different physiological mechanisms at play, but the team notes that they aren't sure what they are or how they work.
Coral respond to bleaching events caused by stress from pollution, overexposure to sunlight, extreme low tides, and changes in ocean temperatures by repairing via this calcification process. However, a 2018 study found that OA impedes the thickening or growing process of coral and decreases skeleton density, making them more vulnerable to breaking. Climate change and the advent of the Anthropocene are only expected to worsen these effects. Oceana notes that before the Industrial Revolution, about 98 percent of coral reefs were surrounded by waters with ideal levels of aragonite, but today the proportion is less than half. A study published reported by CBS found that climate change has caused an 89 percent decrease in new coral in the Great Barrier Reef, further validating that coral reefs are threatened by climate change and its repercussions.
Long-term assessments of OA are scarce and the scientific community is limited in its understanding of how it impacts corals and coralline algae. We do know that if there is a 20 percent increase in current carbon dioxide levels over the next two decades, corals will grow slower and will be less able to overcome even normal pressures.
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By Jessica Corbett
A leading environmental advocacy group marked Native American Heritage Month on Wednesday by urging President-elect Joe Biden, Vice President-elect Kamala Kamala Harris, and the entire incoming administration "to honor Indigenous sovereignty and immediately halt the Keystone XL, Dakota Access, and Line 3 pipelines."
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Returning the ‘Three Sisters’ – Corn, Beans and Squash – to Native American Farms Nourishes People, Land and Cultures
By Christina Gish Hill
Historians know that turkey and corn were part of the first Thanksgiving, when Wampanoag peoples shared a harvest meal with the pilgrims of Plymouth plantation in Massachusetts. And traditional Native American farming practices tell us that squash and beans likely were part of that 1621 dinner too.
Abundant Harvests<p>Historically, Native people throughout the Americas bred indigenous plant varieties specific to the growing conditions of their homelands. They selected seeds for many different traits, such as <a href="https://emergencemagazine.org/story/corn-tastes-better/" target="_blank" rel="noopener noreferrer">flavor, texture and color</a>.</p><p>Native growers knew that planting corn, beans, squash and sunflowers together produced mutual benefits. Corn stalks created a trellis for beans to climb, and beans' twining vines secured the corn in high winds. They also certainly observed that corn and bean plants growing together tended to be healthier than when raised separately. Today we know the reason: Bacteria living on bean plant roots pull nitrogen – an essential plant nutrient – from the air and <a href="http://www.tilthalliance.org/learn/resources-1/almanac/october/octobermngg" target="_blank" rel="noopener noreferrer">convert it to a form that both beans and corn can use</a>.</p><p>Squash plants contributed by shading the ground with their broad leaves, preventing weeds from growing and retaining water in the soil. Heritage squash varieties also had spines that discouraged deer and raccoons from visiting the garden for a snack. And sunflowers planted around the edges of the garden created a natural fence, protecting other plants from wind and animals and attracting pollinators.</p><p>Interplanting these agricultural sisters produced bountiful harvests that sustained large Native communities and <a href="http://dx.doi.org/10.1353/eam.2015.0016" target="_blank">spurred fruitful trade economies</a>. The first Europeans who reached the Americas were shocked at the abundant food crops they found. My research is exploring how, 200 years ago, Native American agriculturalists around the Great Lakes and along the Missouri and Red rivers fed fur traders with their diverse vegetable products.</p>
Displaced From the Land<p>As Euro-Americans settled permanently on the most fertile North American lands and acquired seeds that Native growers had carefully bred, they imposed policies that <a href="https://doi.org/10.1086/ahr/87.2.550" target="_blank">made Native farming practices impossible</a>. In 1830 President Andrew Jackson signed the <a href="https://guides.loc.gov/indian-removal-act" target="_blank">Indian Removal Act</a>, which made it official U.S. policy to force Native peoples from their home locations, pushing them onto subpar lands.</p><p>On reservations, U.S. government officials discouraged Native women from cultivating anything larger than small garden plots and pressured Native men to practice Euro-American style monoculture. Allotment policies assigned small plots to nuclear families, further limiting Native Americans' access to land and preventing them from using communal farming practices.</p><p>Native children were forced to attend boarding schools, where they had no opportunity to <a href="https://doi.org/10.5749/jamerindieduc.57.1.0145" target="_blank">learn Native agriculture techniques or preservation and preparation of Indigenous foods</a>. Instead they were forced to eat Western foods, turning their palates away from their traditional preferences. Taken together, these policies <a href="https://kansaspress.ku.edu/978-0-7006-0802-7.html" target="_blank" rel="noopener noreferrer">almost entirely eradicated three sisters agriculture</a> from Native communities in the Midwest by the 1930s.</p>
Reviving Native Agriculture<p>Today Native people all over the U.S. are working diligently to <a href="https://www.oupress.com/books/15107980/indigenous-food-sovereignty-in-the-united-sta" target="_blank" rel="noopener noreferrer">reclaim Indigenous varieties of corn, beans, squash, sunflowers and other crops</a>. This effort is important for many reasons.</p><p>Improving Native people's access to healthy, culturally appropriate foods will help lower rates of <a href="https://www.cdc.gov/vitalsigns/aian-diabetes/index.html" target="_blank">diabetes</a> and <a href="https://www.apa.org/pi/oema/resources/ethnicity-health/native-american/obesity" target="_blank">obesity</a>, which affect Native Americans at disproportionately high rates. Sharing traditional knowledge about agriculture is a way for elders to pass cultural information along to younger generations. Indigenous growing techniques also protect the lands that Native nations now inhabit, and can potentially benefit the wider ecosystems around them.</p>
By Jake Johnson
Amid reports that oil industry-friendly former Energy Secretary Ernest Moniz remains under consideration to return to his old post in the incoming Biden administration, a diverse coalition of environmental groups is mobilizing for an "all-out push" to keep Moniz away from the White House and demand a cabinet willing to boldly confront the corporations responsible for the climate emergency.
Anger, anxiety, overwhelm … climate change can evoke intense feelings.
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