Dungeness Crabs’ Shells Are Dissolving From the Severity of Pacific Ocean Acidification
As the Pacific Ocean becomes more acidic, Dungeness crabs, which live in coastal areas, are seeing their shells eaten away, according to a new study commissioned by the National Oceanic and Atmospheric Administration (NOAA).
The study authors looked at ocean acidification levels from 2016. They found that the lowered pH is dissolving the shells of young Dungeness crabs in Oregon, Washington and British Columbia. Without strong shells, the young crabs suffer damage to their sensory organs, as CNN reported.
The findings contribute to growing concerns about the viability of the Dungeness crab as atmospheric carbon dioxide, which continues to rise, is absorbed by the Pacific Ocean and increases acidification, as The Seattle Times reported.
"If the crabs are affected already, we really need to make sure we pay much more attention to various components of the food chain before it is too late," said study lead author Nina Bednarsek, a senior scientist with the Southern California Coastal Water Research Project, as CNN reported.
The study was published last week in the journal Science of the Total Environment.
Dungeness crabs are vital to the West Coast fishing industry — netting around $200 million annually. They are also important to tribal and recreational crabbers. The crabs have thrived in coastal waters that have recently become hotspots for ocean acidification, according to The Seattle Times.
Ocean acidification happens when the pH of ocean water drops. The primary cause is an increase in absorption of atmospheric CO2 over a long period. When CO2 is absorbed by seawater, a chain of chemical reactions is set in motion. That causes the sea water to increase its acidity as an increase in hydrogen ions tamps down carbonate ions, which would balance out the water's pH level, as NOAA explained in a statement.
Crustaceans and corals need carbonate ions to help them build strong shells. In their absence, it becomes difficult for crabs, oysters and clams to build shells. It also stops corals from building strong skeletons and it weakens plankton, as CNN reported.
"Decreases in carbonate ions can make building and maintaining shells and other calcium carbonate structures difficult for calcifying organisms," explains NOAA.
Previous research had shown that ocean acidification was causing harm to West Coast pteropods, small free-swimming snails that are food for Dungeness crab, according to The Seattle Times. Direct damage to Dungeness crabs was not expected for many years to come, so the findings have alarmed NOAA scientists.
"We found dissolution impacts to the crab larvae that were not expected to occur until much later in this century," Richard Feely, study co-author and NOAA senior scientist, said as CNN reported.
The research boat that took samples in 2016 did not just find damage to the crab's shell, but also to tiny hair-like structures crabs use to navigate their environments, which is something scientists had never seen before. Crabs without these tiny mechanoreceptors could move slowly and have trouble swimming and finding food, according to CNN.
As for shell damage, the shells showed signs of scarring and abnormal ridging, which may impair a crab's ability to swim, stay buoyant and escape from predators. The damaged crabs were also smaller, which suggests developmental delays, as the Sustainability Times reported.
"We were really surprised to see this level of dissolution happening," Bednarsek said, as The Seattle Times reported.
The authors say their findings mean more research is needed to make new predictions about the future of the Dungeness crab as the Pacific coastal waters continue to absorb more carbon dioxide, according to The Seattle Times.
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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>
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