Wednesday, May 17, 2017

Improving Clam Populations with Sea Grass and Oyster Shell

In the popular press we have seen several articles about ocean acidification adversely affecting the growth of clams and some species of oyster. This article from a Yale Environmental blog does a wonderful job laying out the challenge and two solutions: eel grass that can process CO2 in the water and placing oyster shell. We have been recycling shell at the Mass Oyster Project for over a decade. Oyster shell was once a major part of our estuarine ecosystems. By returning it through recycling or oyster restoration, we are bringing that balance back. 

How Growing Sea Plants Can Help Slow Ocean Acidification

Researchers are finding that kelp, eelgrass, and other vegetation can effectively absorb CO2 and reduce acidity in the ocean. Growing these plants in local waters, scientists say, could help mitigate the damaging impacts of acidification on marine life.
Robert Schwemmer/NOAA
Harvesting kelp, shown here off the California coast, removes CO2 from the ecosystem.
Oregon’s picturesque Netarts Bay has long been known for its oysters. But Netarts, like the whole west coast of North America, is getting more acidic. And the oysters don’t like it.
Since the Industrial Revolution, carbon dioxide in the air has seeped into ocean waters and boosted acidity by 30 percent. Globally, the oceans’ pH has dropped from 8.2 to 8.1, and could drop another 0.4 units by the end of the century. The problem is worse off the west coast of North America, where acidic bottom-waters are brought up to the surface by onshore winds. Corrosive waters like those suck up the building blocks for shells, and can literally eat away at the skeletons of corals.
Last summer, Oregon State University marine ecologist George Waldbusser and his team boated around Netarts Bay planting baby oysters to see how they would fare. The only ones that thrived were those protected by beds of eelgrass, which seemed to swallow up enough carbon dioxide during the peak of each day to give the oysters a break from acid and a window of opportunity for growth.
“Basically nothing outside of those beds survived,” says Waldbusser, who hasn’t yet published the work. Meanwhile, the Whiskey Creek Shellfish Hatchery in Netarts Bay has started only pulling water into their tanks in the afternoon, when photosynthesis peaks and the water is less acidic.
Waldbusser is part of a small team of scientists now exploring the idea that seagrasses, kelps, and shell beds might be able to counteract the rising tide of ocean acidity in local hot spots, making life a little easier for struggling animals. He and other experts on the West Coast Ocean Acidification and Hypoxia Science Panel, which released its first report this April, recommended that scientists and managers push forward such strategies to suck CO2 out of the water.
The idea is a smaller, gentler cousin to grander schemes of geo-engineering. There have been proposals to soak up the ocean’s excess acid by throwing iron, limestone, or olivine into the water, boosting plankton growth, adding the building blocks for shells, or chemically absorbing CO2. But the general response to such plans usually ranges from head-shaking disbelief that they might be feasible or effective, to widespread concern about the possible ecological side effects. The energy needed to mine and distribute rocks, and the unpredictable shift in food webs, have made these schemes unappealing on a global scale. 
One study said seagrass meadows should give corals about an 18 percent boost in growth.
On the local scale, however, lower-cost, lower-risk ecological restoration might have the dual benefit of giving threatened sea creatures both a better place to live and a refuge from ocean acid.
Oysters would not be the only creatures to benefit. Derek Manzello manages a long-term ocean acidification monitoring site at Cheeca Rocks in the Florida Keys, as part of the National Oceanic and Atmospheric Administration’s (NOAA) National Coral Reef Monitoring Program. That particular patch of coral is one of the only reefs in the Florida Keys that is still growing; in other reefs, most corals have died from disease and bleaching since the early 1980s. This is odd because Cheeca Rocks, like other near-shore spots in Florida, sees high temperature swings and large amounts of soil and nutrients dumped into the water, which should limit coral growth. There are several possible explanations for Cheeca Rocks’ resistance to these problematic conditions, including that the corals there might be genetically adapted to thrive in harsh conditions. But another possible explanation is that they are living in a low-acidity refuge created by nearby seagrass beds.
In 2012, Manzello showed that Florida’s inshore waters, including where Cheeca Rocks sits, are packed with dissolved aragonite, the material that corals need to grow. Acids in the water decrease the aragonite saturation value; if it gets below 1, corals and shells start to dissolve. In pre-industrial times, these inshore waters typically had a saturation value of 4.6. Today, most reefs in Florida and the Caribbean have been eked down to 3.8. But Florida’s inshore waters have a happy 4.7.
“This is a huge difference,” says Manzello. The reason is the banks of seagrass growing in Florida’s inshore waters, like turtle grass and manatee grass, that suck up CO2 as they photosynthesize — particularly in the spring.
Another study out that same year showed the same effect in the tropical Indo-Pacific. Seagrass meadows there have the potential to increase aragonite saturation by up to 2.9 units, and the pH by 0.38. That should give corals about an 18 percent boost in growth, making seagrass a potential tool for marine park managers, the authors write.
George Waldbusser/OSU
Stephanie Smith stands in a bed of Zostera marina seagrass in Netarts Bay with the CO2 sensor she designed while a graduate student at Oregon State University.
The potential is huge. Plants in the ocean, from seagrasses to plankton, add up to just 0.05 percent of the plant biomass on land, but are so pervasive and efficient at sucking up carbon that they cycle through roughly the same amount of carbon every day as all the land-based plants. Yet seagrass ecosystems are being wiped out, thanks to everything from pandemic disease to water pollution and coastal construction projects. The rate of loss has skyrocketed from less than 1 percent of global seagrass cover per year in the 1970s to 7 percent annually in the 2000s, making seagrasses one of the planet’s most threatened ecosystems. Efforts to restore or farm such plants could have a host of benefits, including soaking up atmospheric carbon.
Waldbusser cautions that many scientists don’t yet know about the effect of seagrasses on ocean chemistry. Some breeds, like the invasive Zostera japonicaeelgrass in Oregon, tend to shed their leaves in the winter, and the degrading plant matter boosts carbon dioxide levels in the water rather than lowering them. And if the water is swift flowing, then any patches of water made less acidic by plants will likely be swept away before they have a chance to benefit local shellfish or corals.
Seagrasses aren’t the only possible solution. Kelp is also well known for soaking up excess nutrients and making waters cleaner for shellfish. Most academic papers looking at the benefits of kelp don’t even mention acidification. But it didn’t take much for Nichole Price of the Bigelow Laboratory for Ocean Science in Maine to put two and two together. “The biggest challenge in land-based kelp nurseries is keeping the pH low enough because they consume so much CO2,” says Price, who wondered how those same photosynthetic algae were affecting ocean waters.
Price teamed up with Ocean Approved, North America’s first commercial kelp farmer, to put instruments inside and outside of its kelp farms to see what was going on. In as-yet-unpublished work, they show that the aragonite saturation level is half a unit to a full unit higher within the kelp farm. “That’s bigger than the change we expect from ocean acidification,” she says. Next year they plan to map the extent of the impact, and test the effect of the kelp on a mussel farm around the corner. That farm, says Price, has already started growing kelp based on these preliminary results. 
Researchers will soon start the first large-scale project to plant and grow kelp to suck up CO2.
The key, says Price, is to harvest the kelp so that the carbon it extracts gets removed from the ecosystem. It’s hard to compete with Asian kelp suppliers, but local kelp could be dried and used as food or fertilizer, adding a layer of economic diversity to a struggling coastal economy. “There’s a lot of potential for shellfish aquaculture, but people are really hesitant [because of acidification],” says Price, who now heads up Bigelow’s Centers for Venture Research. Pairing up with seaweeds might be the trick to buy new businesses a bit of insurance against future conditions, she says.
This autumn, researchers will start the first large-scale project to intentionally plant and grow kelp to suck up carbon dioxide. The Puget Sound Restoration Fund, based in Bainbridge Island, Washington, won $1.5 million from the Paul G. Allen Ocean Challenge in April 2015 to investigate the potential for sugar kelp to reduce acidity in local waters, where the pH can hit 7.8. Plans call for starting farming an acre of kelp this October.
Ocean waters can be buffered against acids by non-living material, too. Instead of soaking up carbon dioxide, the strategy here is to add more carbonate to the water. That shifts the aragonite saturation point and, again, makes it easier for shells to grow. 
Nearly every estuary that once had a thriving oyster industry hosts an effort to put old shells back into the water, says Waldbusser. Most, if not all, of these projects are focused on giving the oysters or other shellfish something to grow on — their babies prefer to sit on piles of old shells, rather than getting buried or choked by mud. The fact that these shells help to buffer water acidity is an added bonus.
The Chesapeake Bay, he notes, has seen the largest oyster reef restoration effort to date and also possibly the largest (and unintentional) ocean acidification buffering experiment. About 196 million bushels of dredged oyster shells were put back into Chesapeake Bay from 1960 until 2006, before the project coordinators ran low on shells. They’re still about 100 million bushels short of where the Chesapeake’s ecology would have been had oysters not been extracted for centuries, notes Waldbusser, and the effects on the bay’s complex water chemistry have so far been hard to track. But that doesn’t mean that shells can’t shift pH significantly under different conditions.
In previous work off the coast of Maine, Waldbusser’s team, led by Mark Green of Saint Joseph’s College of Maine, mixed old ground-up shells with ocean sediments and replanted them. They then looked to see how that affected oysters. Three times as many oyster larvae settled in the shell-rich soils as in the non-shelled soils, they found. The reason, Waldbusser thinks, is because of a change in water acidity within the pores of the sediment.
Examining How Marine Life Might Adapt to Acidified Oceans
In an interview with Yale Environment 360, marine biologist Gretchen Hofmann discusses how well mollusks and other shell-building organisms might evolve to live in increasingly corrosive ocean conditions caused by soaring CO2 emissions.READ MORE
“You have this incredibly hostile environment in the pore water, which is generally more acidic than the overlying water,” says Waldbusser. “Mix shell in and it’s a little less hostile.”
Waldbusser is familiar with other proposed ways of shifting ocean pH. He wrote a proposal to use the waste CO2 emitted from a hatchery to dissolve calcium carbonate rocks and bubble the products back into the ocean, helping to buffer acidity in much the same way as is done in home aquariums. But it didn’t get funded. “There are lots of technologies that exist and things you can do, but it comes back to scalability and unintended consequences,” says Waldbusser. Using rocks to buffer ocean water, for example, involves using energy to treat the minerals beforehand so they dissolve, and then you have to worry about toxic levels of nickel or cadmium hitching a ride along with the rocks.
In the end, says Waldbusser, “I always come back to restoration.” Replanting the seagrasses or shell banks that used to exist in an estuary is much safer, and often easier, than some industrial schemes. And, he adds, it probably comes with “built-in benefits that we don’t even recognize.”


  1. Asian online gambling
    คาสิโนIs an online casino that is open to the online gambling of Asian gamblers for risk providers, this is considered one of the online casino game providers are famous for. Circles for today, playing online gambling online is considered to be excellent because the number of players to use the most. And importantly, playing online gambling games on the online casino site also has many online gambling games for you to choose from, you can play all kinds of online games on our online casino. By just surfing the internet, whenever you have an internet connection, you can access all the online risk games on the web. Lahore online casinos have the pleasure and excitement can challenge the player to become billionaires by only player to start playing games online bets with us. You can play all kinds of online gambling games. And players can also get money into the pockets of the players, players can begin to enjoy and start playing more than a hundred online gambling games on our online casino site as well. Day and night, the player can join us at any part of the web. Sbobet

  2. Online Bingo Games That's right for you
    คาสิโนออนไลน์Is one of the web Online casino famous. The online gambling service has been open for more than 10 years with a service system that is popular and always develops a system of play. Make this online casino site popular and get. Many Asian gamers choose to play online casino games with online gambling sites because gamblers can choose to gamble online at all online games. Online casino sites and on-line casino websites are also filled with hundreds of famous online gambling sites. The orderly and graceful, so access to the pages of this online casino is considered that the service is very simple. You only have Internet access, you can play online gambling games that are placed on our online casino website and then call it online casino online gambling online play. It's free. Every gambler can play free online gambling every time a gambler thinks about online gambling. The delighted to join and play games of chance online. The favorite players are those from the webpage. บาคาร่าออนไลน์

  3. Online casino games that measure players.
    GclubIt is the online gambling option that users enjoy every moment with the online casino games you like. With gambling, online gambling is the better place to gamble because you can gamble. Our next step is to gamble online through the internet. Available for a variety of festivities along with a taste of reliable gambling every game. Nowadays, online gambling is a game where anyone. They all bet. Because it is not just a joy to be alone. You can also profit from online gambling as a new online gambling game because it allows anyone to bet on every single online gambler. Online casino games that are ready to serve customers at any time, you just have the Internet. Come play a variety of online gambling games online with our online games to win a lot. No matter what you want to gamble online, we are ready to open the service. Many types of online gambling games and most popular online casino games. Entertainment and Going to Bet on Multiplayer Online Gambling in All Games Click on the Website. Royal1688

  4. The best online gambling games.
    Ruby888Is a web g club The leading online casino that has been providing online gambling for more than 10 years for the fun and new opportunity to make online casino games more attractive due to playing games. Online gambling is another new way to add fun to the game, double the amount of gambling and more importantly, playing the game. Online is also an opportunity for new players can make money with fun is endless. Because of that, playing online gambling is another new joy. The gambler can choose to play online gambling more easily with just the Internet, only the gambler can play all online casino games that are available on the gambling website. This online casino. And most importantly, online gambling games on the computer screen can be played at any time the player wishes by just having an internet connection. Every time an internet gambler has an internet connection, the player can enter online gambling. All on the casino site. Our gambling clubs and major risk takers can also start enjoying and play casino games online with gamblers around the world on the webIBCbet

  5. Online gambling New opportunity of wealth
    Goldclub SlotEntrance to online gambling games new opportunities most convenient. For playing online casino games in the present time, there are many opportunities to choose the player can choose whether the player will play gambling online games with gambling club website. Online casino New camp that the player can choose to play online gambling games in any style, the player can set the time to play online casino games on their own. Because of the service system of the modern web gclub. This online casino players can determine. Type and duration of playing online casino games with the player itself, because now playing online gambling games is another good way for players of all ages to play. Play online gambling games where the player does not have to travel to foreign countries every time a player has an internet connection. Play the lottery online format on the casino site. Gclub has the fun and excitement to make playing online casino games all interesting and easy to play as well. The player can find and play online casino games that you love all the time that the player needs because of the service of the web. Our casino is ready to serve you every time. The player can contact us for details before starting the gameคาสิโนออนไลน์

  6. The original bets are universal.
    Ruby888It is a site that is open to the problem of playing the game through the computer network. The instant excellent service. You will find a variety of risky games. And the games are broadcast live. Directly to your residence every day, such as casino games that are popular in modern times, slots, roulette, poker, slots, slots, online. And many more that you will play baccarat online. And other games can be delivered directly to the residence. Or wherever you go, you can play games anywhere. With a desirable design for everyone. Make it easy to use and let you enjoy every minute. Get easy money, minutes per minute. Ensure a steady, steady eye to fascinate us with a distinctly. Join us for fun with our online risk website today. Get paid immediately. Dividend to the new team 30% of the minimum registration open from 500 baht up to 15000 baht. This excellent choice is not a regular, hurry to register with us at. Website IBCbet

  7. The thrill of playing casino games.
    Sbobet It is a site to create pleasure and excitement with casino games. In the present day, there are websites that provide services in the field of games, gambling, internet networks, emerging to provide services to many online gamblers. And our online betting site is a leading provider of gambling games that have been fashioned to cater to any one who has a keen interest in it. Gambling games are popular at the risk of popular games such as slot games, baccarat, online gambling, as well as websites. Gambling Online Betting These games also provide all types of gambling games. Whether it's football, every game, the most popular matches. The most popular sport betting is to play online. The game of gambling to make money for gamblers enough. Our Online Betting Sites are also considered to be online gambling providers that are widely credited by the risk takers. Because of the gambling games here. When a player wins a bet The winnings are instantly paid out and the amount wagered. There are also promotions for gamblers to enjoy each month as well. And all this you can find at the website. คาสิโน