Biodiversity Helps Coral Reefs Thrive and Could Be Used Strategically to Save Them

By Cody Clements
Coral reefs are home to so many species that they often are called "the rainforests of the seas." Today they face a daunting range of threats, including ocean warming and acidification, overfishing and pollution. Worldwide, more than one-third of all coral species are at risk of extinction.
I am one of many scientists who are studying corals to find ways of helping them survive and recover. As a recent report from the National Academies of Science, Engineering and Medicine shows, researchers are exploring many different strategies. Some, such as managed breeding to make corals more tolerant of stresses, are already being developed at small scales. Others, such as moving corals to colonize new areas, have not been tested yet.
My own work examines whether greater diversity of coral species on reefs can help corals survive and thrive. In a study published earlier this year, my colleague Mark Hay and I found evidence that the answer is yes. This finding could help to inform broader strategies for making coral reefs more resilient in altered oceans.
In Nature, More Is Better
Are ecosystems healthier if they contain many species than if they harbor only a few? This is a central question in ecology. Generally, scientists have found that ecosystems with more diverse foundation species – those that define a system and are inseparable from it, such as trees in a forest – tend to be healthier and function better.
Until recently, no one had applied this test to coral reefs. But we do know that healthy coral reefs are diverse, structurally complex ecosystems dominated by corals. In contrast, reefs that have been damaged by stresses such as coral bleaching events tend to become simplified, less diverse landscapes, often dominated by seaweeds.
For our study we chose a reef area on the southwestern coast of Fiji's main island, Viti Levu, in the South Pacific. Many reefs along this coast have been heavily degraded by overfishing and other human-related activities, reducing coral cover and allowing seaweeds to dominate.
There are hundreds of coral species across the Pacific, but at smaller scales, we found just five species or fewer during preliminary surveys conducted on the degraded reef at our site. Since these conditions mirror what is happening to many reefs worldwide, we saw it as an ideal place to test whether coral diversity matters for the "new normal" that we expect to see on reefs of the future.
Underwater Gardens
Our team created 48 concrete plots on the sea floor of the degraded reef, which served as the bases for experimental coral gardens. We created single-species gardens that each contained one of three coral species – Pocillopora damicornis, commonly known as cauliflower coral; Porites cylindrica, also known as yellow finger coral; and Acropora millepora, one of a number species known as staghorn corals. We also planted mixed gardens containing all three species.
We chose these corals because they are common to reefs across the Pacific and are representative of different coral families that have shown varying responses to a variety of harmful disturbances. In all, each garden contained 18 coral individuals, for a total of 864 corals.
To assess each coral's performance as it grew, we needed to remove them from their plots periodically. So we cut off the tops of hundreds of soda bottles and planted an individual coral in the upside-down neck of each bottle with epoxy putty. We embedded the bottle caps into our concrete slabs so that we could easily unscrew each bottle neck to examine the coral it held, then screw it back into its base. Over 16 months we weighed the corals and tracked other measures of their well-being, including tissue death and colonization of each garden by harmful seaweeds.
Experimental coral gardens on a degraded reef in Fiji. Gardens with a mix of coral species performed better than gardens containing only one species.
Cody Clements / CC BY-ND
We consistently found that corals grown in mixed-species gardens performed better than those in single-species plots. Within four months, coral growth in the mixed-species gardens was even exceeding the best-performing single-species gardens. This suggests that different species may benefit each other in yet unknown ways, at least during early stages of a coral community's development.
Examples of single- and mixed-species coral gardens through time during our 16-month experiment. At four months, mixed-species gardens were outperforming single-species gardens in multiple ways – growing faster on average than even the best performing single-species gardens (Acropora millepora). By 16 months, growth was comparable between mixed-species and Acropora gardens, but aggregate performance of single-species gardens continued to lag behind their mix-species counterparts.
Clements and Hay, 2019 / CC BY-ND
Why Is More Better?
The next question is what drove the effects that we observed. We hope to investigate a number of leads in future experiments. For example, farmers commonly observe that planting a diverse mix of crops helps to reduce the spread of infectious diseases among individuals. Could the same be true for coral reefs?
Our initial findings offer both concern and hope for the future of coral reefs. If diversity is integral to coral well-being, then continued species loss could dramatically alter these ecosystems in ways that lead to further reef decline. How many parts can be removed from the "ecosystem engine" before it breaks down?
That said, many of the strategies in the National Academies report involve using biodiversity – both at the genetic and species level – to enhance coral reef resilience. Examples include cross-breeding corals between populations; altering coral genes to give them new functions, such as higher heat tolerance; and moving stress-tolerant corals or coral genes to new locations.
Promising advances in technology, such as mapping coral reefs from the air, may also help researchers assess coral health and determine which species they contain. This baseline information may help better inform management and restoration efforts.
Corals are in trouble, but they aren't down for the count yet. Perhaps harnessing the power of their remaining biodiversity can help give them a fighting chance.
Researchers Use Technology and Nature to Save Hawaii’s Coral Reefs From Invasive Algae https://t.co/FIeqApvnCC
— PFMC (@PacificCouncil) August 17, 2018
Cody Clements is a postdoctoral fellow at the Georgia Institute of Technology.
Disclosure statement: Cody Clements receives funding from the National Science Foundation, the National Institutes of Health, the National Geographic Society, and the Teasley Endowment to the Georgia Institute of Technology.
Reposted with permission from our media associate The Conversation.
World's 5% 'Polluter Elite' Responsible for 37% of Global Emissions Growth, Study Concludes
By Brett Wilkins
As world leaders prepare for this November's United Nations Climate Conference in Scotland, a new report from the Cambridge Sustainability Commission reveals that the world's wealthiest 5% were responsible for well over a third of all global emissions growth between 1990 and 2015.
The report, Changing Our Ways: Behavior Change and the Climate Crisis, found that nearly half the growth in absolute global emissions was caused by the world's richest 10%, with the most affluent 5% alone contributing 37%.
"In the year when the UK hosts COP26, and while the government continues to reward some of Britain's biggest polluters through tax credits, the commission report shows why this is precisely the wrong way to meet the UK's climate targets," the report's introduction states.
The authors of the report urge United Kingdom policymakers to focus on this so-called "polluter elite" in an effort to persuade wealthy people to adopt more sustainable behavior, while providing "affordable, available low-carbon alternatives to poorer households."
The report found that the "polluter elite" must make "dramatic" lifestyle changes in order to meet the UK's goal — based on the Paris climate agreement's preferential objective — of limiting global heating to 1.5°C, compared with pre-industrial levels.
In addition to highlighting previous recommendations — including reducing meat consumption, reducing food waste, and switching to electric vehicles and solar power — the report recommends that policymakers take the following steps:
- Implement frequent flyer levies;
- Enact bans on selling and promoting SUVs and other high polluting vehicles;
- Reverse the UK's recent move to cut green grants for homes and electric cars; and
- Build just transitions by supporting electric public transport and community energy schemes.
"We have got to cut over-consumption and the best place to start is over-consumption among the polluting elites who contribute by far more than their share of carbon emissions," Peter Newell, a Sussex University professor and lead author of the report, told the BBC.
"These are people who fly most, drive the biggest cars most, and live in the biggest homes which they can easily afford to heat, so they tend not to worry if they're well insulated or not," said Newell. "They're also the sort of people who could really afford good insulation and solar panels if they wanted to."
Newell said that wealthy people "simply must fly less and drive less. Even if they own an electric SUV, that's still a drain on the energy system and all the emissions created making the vehicle in the first place."
"Rich people who fly a lot may think they can offset their emissions by tree-planting schemes or projects to capture carbon from the air," Newell added. "But these schemes are highly contentious and they're not proven over time."
The report concludes that "we are all on a journey and the final destination is as yet unclear. There are many contradictory road maps about where we might want to get to and how, based on different theories of value and premised on diverse values."
"Promisingly, we have brought about positive change before, and there are at least some positive signs that there is an appetite to do what is necessary to live differently but well on the planet we call home," it states.
The new report follows a September 2020 Oxfam International study that revealed the wealthiest 1% of the world's population is responsible for emitting more than twice as much carbon dioxide as the poorest 50% of humanity combined.
Reposted with permission from Common Dreams.
- Small Percentage of Frequent Flyers Are Driving Global Emissions ... ›
- World's Richest People Gained $1.8 Trillion in 2020 - EcoWatch ›
- Tourism Responsible for 8% of Global Greenhouse Gas Emissions ... ›
By Paul Brown
It may come as a surprise to realize that a plant struggling for survival in a harsh environment is also doing its bit to save the planet from the threats of the rapidly changing climate. But that's what Mexico's cactuses are managing to do.
Research published in the journal The Science of Nature shows that desert soils supporting a high density of cactus contain large quantities of stored bio-minerals (minerals produced by living organisms), formed by the action of the plants in extracting carbon dioxide from the atmosphere.
Not only that. Cactuses can also be harvested, processed and turned into a form of leather used to make fashion accessories like purses and wallets.
These two attributes have been turned into a successful business by a Mexican/American company, CACTO. It claims to be the first "carbon negative fashion company in the Americas" − in other words, its activities remove more carbon from the atmosphere than it creates in making and marketing its products.
No Animals Involved
This is a bold claim in an industry struggling with its poor environmental record. According to McKinsey and Co. the worldwide fashion industry emits about the same amount of greenhouse gases as France, Germany and the United Kingdom combined. But CACTO gives Mexico's cactuses special treatment.
CACTO's products are vegan and so allow a growing class of consumers to buy leather objects that are made without any animal products.
The research into the ability of cactus to extract carbon from the atmosphere and store it was carried out on one cactus species, the saguaro (Carnegiea gigantea), which can grow to 40 feet.
It is native to the Sonoran desert in Arizona and the Mexican state of Sonora, and shares with all other cactus varieties the same abilities for dealing with carbon. This has proved a bonus for CACTO because cactuses are the most numerous plants in Mexico.
CACTO's plantations are organic, fed by rainwater, free of herbicides and pesticides, and renewable, and after the ears, or leaves; of the cactus are harvested, the plant grows a replacement in six to eight months. This regeneration allows repeat harvesting. The leaves are then sun-dried to avoid using any electricity. The company's products (available only in green or black) are on sale in more than 100 countries.
CACTO was founded by Jesus Chavez, a climate campaigner, and was designed to have sustainability as a guiding principle at the core of its operation. The entire production cycle is closely monitored by its staff, from the sourcing of materials to production, packaging, distribution and shipping.
Through a partnership with a Swiss non-profit organisation, On a Mission, CACTO says its staff have measured and offset 150% of its CO2 emissions through sustainable reforestation worldwide.
The measurement and offsetting process will take place every six months for the next 10 years. Through several emergent partnerships, the company says it aims to offset at least 1000% of the emissions it generates by the end of 2021.
Engaging Entrepreneurs
Jesus Chavez said: "If we want to succeed in reaching net zero carbon emissions well before 2050 and avoid the worst consequences of climate change, we must all work in concert in whatever capacity we are able to.
"Industries across the board need to benefit from existing technology and offsetting programs to become carbon-negative, and to invest in new research and innovation to reach that goal faster. The decisions we make this decade will determine the fate of humanity for centuries to come. It is up to us now."
He said customers around the world wanted alternatives to materials that increased pollution and to unethical manufacturing processes.
CACTO hopes to inspire a new generation of entrepreneurs to make clear what has been evident to specialists for decades, that decoupling emissions from economic growth is not only feasible, but is the smartest, fastest and most responsible way to grow. Mexico's cactuses bear a heavy responsibility on their ears − or leaves − or branches.
Reposted with permission from Climate News Network.
Climate change, activities that contribute to it, and dams pose grave threats to America's rivers, according to American Rivers.
The annual report ranks the county's 10 rivers most endangered by human activity that also have a critical decision point coming in the next year that could change the river's fate.
Four dams are choking the Snake River — earning it the top spot in the report — obstructing salmon and posing an existential threat to Native American tribes in the region who depend on the fish for food, culture and their identities.
Advocates are calling on President Biden to remove the federal dams and revitalize the river and its ecosystem.
Toxic coal ash pollutes the Lower Missouri, which also is experiencing an increase in climate-driven flooding, putting it second on the list, while Iowa's Raccoon River, at number nine, faces threats from industrial agriculture.
Between them are rivers befouled by sewage, polluted or threatened by mining, and otherwise dammed or mismanaged.
"Rivers are among the most degraded ecosystems on the planet, and threats to rivers are threats to human health, safety and survival," American Rivers head Tom Kiernan said.
"If we want a future of clean water and healthy rivers everywhere, for everyone, we must prioritize environmental justice."
For a deeper dive:
The Guardian, USA Today, Mother Jones, Reuters, E&E
For more climate change and clean energy news, you can follow Climate Nexus on Twitter and Facebook, sign up for daily Hot News, and visit their news site, Nexus Media News.
Japan will release radioactive wastewater from the failed Fukushima nuclear plant into the Pacific Ocean, the government announced on Tuesday.
The water will be treated before release, and the International Atomic Energy Agency said the country's plans were in keeping with international practice, The New York Times reported. But the plan is opposed by the local fishing community, environmental groups and neighboring countries. Within hours of the announcement, protesters had gathered outside government offices in Tokyo and Fukushima, according to NPR.
"The Japanese government has once again failed the people of Fukushima," Greenpeace Japan Climate and Energy Campaigner Kazue Suzuki said in a statement. "The government has taken the wholly unjustified decision to deliberately contaminate the Pacific Ocean with radioactive wastes."
The dilemma of how to dispose of the water is one ten years in the making. In March 2011, an earthquake and tsunami in northeastern Japan killed more than 19,000 people and caused three of six reactors at the Fukushima Daiichi nuclear power plant to melt down, The New York Times explained. This resulted in the biggest nuclear disaster since Chernobyl, and the cleanup efforts persist more than a decade later.
To keep the damaged reactors from melting down, cool water is flushed through them and then filtered to remove all radioactive material except for tritium. Up until now, the wastewater has been stored on site, but the government says the facility will run out of storage room next year. Water builds up at 170 tons per day, and there are now around 1.25 million tons stored in more than 1,000 tanks.
The government now plans to begin releasing the water into the ocean in two years time, according to a decision approved by cabinet ministers Tuesday. The process is expected to take decades.
"On the premise of strict compliance with regulatory standards that have been established, we select oceanic release," the government said in a statement reported by NPR.
Opposition to the move partly involves a lack of trust around what is actually in the water, as NPR reported. Both the government and Tokyo Electric Power Co., which operates the plant, say that the water only contains tritium, which cannot be separated from hydrogen and is only dangerous to humans in large amounts.
"But it turned out that the water contains more radioactive materials. But they didn't disclose that information before," Friends of the Earth Japan campaigner Ayumi Fukakusa told NPR. "That kind of attitude is not honest to people. They are making distrust by themselves."
In February, for example, a rockfish shipment was stopped when a sample caught near Fukushima tested positive for unsafe levels of cesium.
This incident also illustrates why local fishing communities oppose the release. Fish catches are already only 17.5 percent of what they were before the disaster, and the community worries the release of the water will make it impossible for them to sell what they do catch. They also feel the government went against its promises by deciding to release the water.
"They told us that they wouldn't release the water into the sea without the support of fishermen," fishery cooperative leader Kanji Tachiya told national broadcaster NHK, as CBS News reported. "We can't back this move to break that promise and release the water into the sea unilaterally."
Japan's neighbors also questioned the move. China called it "extremely irresponsible," and South Korea asked for a meeting with the Japanese ambassador in Seoul in response.
The U.S. State Department, however, said that it trusted Japan's judgement.
"In this unique and challenging situation, Japan has weighed the options and effects, has been transparent about its decision, and appears to have adopted an approach in accordance with globally accepted nuclear safety standards," the department said in a statement reported by The New York Times.
But environmentalists argue that the government could have found a way to continue storing waste.
"Rather than using the best available technology to minimize radiation hazards by storing and processing the water over the long term, they have opted for the cheapest option, dumping the water into the Pacific Ocean," Greenpeace's Suzuki said.
- Japan's New Environmental Minister Calls for Closing Down All ... ›
- Radiation Along Fukushima Rivers Up to 200 Times Higher Than ... ›
Scientists have maneuvered an underwater robot beneath Antarctica's "doomsday glacier" for the first time, and the resulting data is not reassuring.
Antarctica's Thwaites Glacier is referred to as the doomsday glacier because every year it contributes four percent to global sea level rise and acts as a stopper for the West Antarctic Ice Sheet. If the glacier were to collapse and take the sheet with it, that would raise global sea levels by around 10 feet. Now, a study published in Science Advances on April 9 warns that there is more warm water circling below the glacier than previously believed, making that collapse more likely.
"Our observations show warm water impinging from all sides on pinning points critical to ice-shelf stability, a scenario that may lead to unpinning and retreat," the study authors wrote. Pinning points are areas where the ice connects with the bedrock that provides stability, Earther explained.
The new paper is based on a 2019 expedition where an autonomous submarine named Ran explored the area beneath the glacier in order to measure the strength, salinity, oxygen content and temperature of the ocean currents that move beneath it, the International Thwaites Glacier Collaboration explained in a press release.
"These were the first measurements ever performed beneath the ice front of Thwaites glacier," Anna Wåhlin, lead author and University of Gothenburg oceanography professor, explained in the press release. "Global sea level is affected by how much ice there is on land, and the biggest uncertainty in the forecasts is the future evolution of the West Antarctic Ice Sheet."
This isn't the first instance revealing the presence of warm water beneath the glacier. In January 2020, researchers drilled a bore hole through the glacier and recorded temperature readings of more than two degrees Celsius above freezing, EcoWatch reported at the time.
However, Ran's measurements were taken earlier and allow scientists to understand the warmer water's movement in more detail. Scientists now know that water as warm as 1.05 degrees Celsius is circulating around the glacier's vulnerable pinning points.
"The worry is that this water is coming into direct contact with the underside of the ice shelf at the point where the ice tongue and shallow seafloor meet," Alastair Graham, study co-author and University of Southern Florida associate professor of geological oceanography, told Earther. "This is the last stronghold for Thwaites and once it unpins from the sea bed at its very front, there is nothing else for the ice shelf to hold onto. That warm water is also likely mixing in and around the grounding line, deep into the cavity, and that means the glacier is also being attacked at its feet where it is resting on solid rock."
While this sounds grim, the fact that researchers were able to obtain the data is crucial for understanding and predicting the impacts of the climate crisis.
"The good news is that we are now, for the first time, collecting data that will enable us to model the dynamics of Thwaite's glacier. This data will help us better calculate ice melting in the future. With the help of new technology, we can improve the models and reduce the great uncertainty that now prevails around global sea level variations," Wåhlin said in the press release.
- Scientists Identify Tipping Points for Antarctica Glacier - EcoWatch ›
- Record Warm Water Measured Beneath Antarctica's 'Doomsday ... ›
- Antarctica's 'Doomsday Glacier' Is Starting to Crack - EcoWatch ›