While coral reefs around the world are dying from the effects of ocean acidification and global warming, one little section of the world, Kāne’ohe Bay off the windward side of Oahu, Hawaii, is defying that trend, as certain species of the corals in the bay are actually thriving.
Researchers with the University of Hawaii at Manoa are calling these corals super corals, because not only are they thriving in warm and acidic waters, the corals survived a massive sewage spill in the bay around 30 years ago. They hope that the corals offer a study for reef resilience.
“We won’t save every coral or every reef — many are already gone — but neither is it inevitable that we are going to lose all of them,” Christopher Jury, a marine biologist at the University of Hawaii, told DiscoverMagazine.com. “If we seriously reduce the rate of climate change and the intensity of local stressors, we can still give the survivors a chance.” Jury is the lead author of the study that describes how these corals are surviving one of the most heavily used and popular bays in Hawaii.
The bay suffered from dredging, coastal development and the dumping of sewage from 1930 to 1970, killing 95 percent of the bay’s corals. In 1978, the sewage outlets were relocated and the corals began to thrive again, according to the study. Between 50 percent and 95 percent of the corals recovered by 1998, in what Jury said was in waters that are warmer and more acidic than neighboring bodies of water.
“I began to realize that the temperature and chemistry conditions in Kāne’ohe Bay are very similar to the conditions that many people predict will kill corals off globally, yet the reefs in the bay seem to be thriving, making the area incredibly valuable as a possible window into the future,” Jury told DiscoverMagazine.com.
The researchers collected frags from the three dominant coral species in Kāne’ohe Bay and neighboring Waimānalo Bay: Montipora capitata, Pocillopora acuta and Porites compressa. While the bays are just 11 miles from each other, Waimānalo Bay has better reef water exchange with offshore waters than does Kāne’ohe Bay. And you would expect Waimānalo Bay corals to fare better, but in the research lab, they did not.
The coral frags were then brought into a laboratory where they were assessed for pH and temperature tolerance. The Kāne’ohe Bay corals Poc. acuta and M. capitata were more tolerant of the higher temperatures than the same species from Waimānalo Bay while Por. compressa, didn’t show any difference between the locations. Ph didn’t factor into the survival of any of the species.
The researchers also noted that the corals from Kāne’ohe Bay not only tolerated the warming water temperatures and the more acidic water of the bay, but they also grew faster than the frags taken from Waimānalo Bay.
“In contrast with many projections, we find that at least these corals do in fact harbor a lot of individual variation for temperature and chemistry tolerance and that the hardy members of the population were able to drive rapid reef recovery in Kāne’ohe Bay in spite of the warmer, more acidic conditions found there,” Jury said.
The complete paper “Adaptive responses and local stressor mitigation drive coral resilience in warmer, more acidic oceans” can be read on the Royal Society Publishing website.
United Nations biodiversity experts say that one million species face extinction due to human activities, according to a summary of a report that will be released later this year, and the UNESCO director has put the world on notice.
“Following the adoption of this historic report, no one will be able to claim that they did not know,” – UNESCO Director-General Audrey Azoulay, the head of the United Nations Educational, Scientific and Cultural Organization said in a statement released to the media. “We can no longer continue to destroy the diversity of life. This is our responsibility towards future generations.”
Azoulay said that the importance of diversity, notably the diversity within species, between species and of ecosystems must be protected and is as vital as fighting climate change.
The report, which was approved by more than 130 government delegations at UNESCO headquarters, is comprised of data compiled by 400 experts from 50 countries. It looks into the state of nature and ecosystems and how nature is changed by human activity. It also delves into the progress of UN international goals, including the Sustainable Development Goals (SDGs), the Aichi Biodiversity Targets and the Paris Agreement on climate change, of which the United States withdrew under the Trump regime. Some key highlights of the report
One in four species is at risk The report says that human activities “threaten more species now than ever before” due in part to the fact that 25 percent of of species in plant and animal groups are vulnerable. They cite the a further acceleration in the “global rate of species extinction” that the report says is 10 times higher than the average over the last 10 million years. One million species face extinction within decades unless we take action to reduce “the intensity of drivers of biodiversity loss.”
Crop security is threatened long term The report states that wild relatives of domesticated food crops are needed for long term food security, and currently lack effective protection, and the status of wild relatives of domesticated birds and mammals is getting worse. The report states that when there are reductions in the diversity of cultivated crops, crop wild relatives and domesticated breeds will cause farming to be less resilient against future climate change, crop and animal pests and pathogens.
Marine pollution has increased tenfold since 1980 “Marine plastic pollution in particular has increased tenfold since 1980, affecting at least 267 species”, the report says. The report says 86 percent of marine turtles, 44 percent of seabirds and 43 percent of marine mammals have been negatively affected by marine plastic pollution.
“The loss of species, ecosystems and genetic diversity is already a global and generational threat to human well-being,” Sir Robert Watson, the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES) Chair said in the statement. “Protecting the invaluable contributions of nature to people will be the defining challenge of decades to come. Policies, efforts and actions – at every level – will only succeed, however, when based on the best knowledge and evidence.”
Other key takeaways in the report:
Three-quarters of the land-based environment and about 66% of the marine environment have been significantly altered by human actions. On average these trends have been less severe or avoided in areas held or managed by Indigenous Peoples and Local Communities.
More than a third of the world’s land surface and nearly 75% of freshwater resources are now devoted to crop or livestock production.
The value of agricultural crop production has increased by about 300% since 1970, raw timber harvest has risen by 45% and approximately 60 billion tons of renewable and nonrenewable resources are now extracted globally every year – having nearly doubled since 1980.
Land degradation has reduced the productivity of 23% of the global land surface, up to US$577 billion in annual global crops are at risk from pollinator loss and 100-300 million people are at increased risk of floods and hurricanes because of loss of coastal habitats and protection.
In 2015, 33% of marine fish stocks were being harvested at unsustainable levels; 60% were maximally sustainably fished, with just 7% harvested at levels lower than what can be sustainably fished.
Urban areas have more than doubled since 1992.
Plastic pollution has increased tenfold since 1980, 300-400 million tons of heavy metals, solvents, toxic sludge and other wastes from industrial facilities are dumped annually into the world’s waters, and fertilizers entering coastal ecosystems have produced more than 400 ocean ‘dead zones’, totalling more than 245,000 km2 (591-595) – a combined area greater than that of the United Kingdom.
Negative trends in nature will continue to 2050 and beyond in all of the policy scenarios explored in the Report, except those that include transformative change – due to the projected impacts of increasing land-use change, exploitation of organisms and climate change, although with significant differences between regions.
The full report, which is expected to be more than 1,500 pages, is scheduled to be released later this year.
Local efforts to reduce pollution on coral reefs is not enough to save the world’s coral reefs, as a global effort to reduce global warming is needed to help these reef ecosystems, according to a National Science Foundation study put out by Oregon State University and University of California, Santa Barbara researchers.
The researchers collected Pocillopora meandrina cauliflower coral samples off the coast of Moorea in French Polynesia and exposed them to stressors that affect them in the wild. They examined how the dinoflagellates, fungi, bacteria and archaea that comprise a coral microbiome reacted.
“We subjected the corals to three stressors: increased temperature, nutrient enrichment—meaning pollution—and manual scarring,” Rebecca Maher, lead author of the study and a graduate research fellow in the OSU College of Science, said in a statement released to the media. “We scarred the corals with pliers, which was meant to simulate fish biting the coral.”
They then examined how these coral stressors interacted to negatively affect the coral microbiome and coral health.
“We found that with every form of stress, the amount of ‘friendly’ bacteria decreases in the coral and the amount of ‘unfriendly’ or disease-related bacteria increases,” Maher said. “Stressed corals had more unstable microbiomes, possibly leading to more disease and coral death.”
The researchers determined that stressing the corals with two stressors didn’t necessarily result in twice the stress on the coral, as there was less stress in some instances, but they determined that all three stressors together fueled each other to the detriment of the corals.
“Two stressors did not always compound each other’s negative effects but instead interacted antagonistically to produce less-than-additive effects on changes in microbial community distinctness, instability and diversity,” Maher said. “However, when three forms of stress were experienced by corals, the microbiomes dramatically changed, showing that stress can act synergistically to amplify the negative effects of single stressors.”
While the simulated fish bites definitely stressed the corals, the high temperatures were the death knell for the marine organisms.
“There is no magical number of stressors, but multiple stressors may interact in ways that we would not expect and that can depend on the type of stressor – human vs. environmental – or the severity of the stress,” Maher said. “Therefore, we should take care to understand these interactions before attempting to manage them with conservation actions. Our work is an important step in informing those actions by providing insights into how the coral and its microbiome will change under increasing human impacts.”
While we as ocean lovers can do our part to reduce the effects of global warming, it is imperative that people around the world continue to pursue a path to reduce our carbon footprint, so our coral reefs can recover from a warming planet.
Scientists meeting at the Blue Oceans Conference last month in Monrovia, Liberia, had ocean acidification on their minds and met during a side conference in an effort to develop a strategy on how to tackle the problem that research shows has lasting negative effects on the world’s oceans.
The scientists, part of the Ocean Acidification Africa (OA-Africa) network supported by the International Atomic Energy Agency, relayed the needs and challenges that Africa faces when dealing with ocean acidification. Because many coastal African nations depend on the oceans and marine ecosystems for food and livelihood, the scientists will try and determine how ocean acidification will impact local species.
“Nuclear and isotopic techniques are particularly important tools to assess the effects of ocean acidification on marine organisms and to better understand a host of other pressing environmental issues” Peter Swarzenski of the IAEA Environment Laboratories in Monaco said during the side event. Other topics discussed at the conference included marine plastic pollution, sustainable fisheries and the “Blue Economy,” which promotes “the sustainable use of ocean resources for economic growth, improved livelihoods and jobs, and ocean ecosystem health.”
“African countries are among the most vulnerable to climate change and ocean acidification. OA-Africa is committed to keep raising awareness and fill research gaps in its members’ countries,” Sheck Sherif, co-chair of OA-Africa said in a statement released by the IAEA.
Ocean acidification occurs when the ocean absorbs carbon dioxide that is created by human activities. The carbonate chemistry and acidity of the ocean water is changed. Studies have determined that these changes have detrimental effects on marine organisms such as corals, and mollusks.
A heatwave in early 2011 caused water temperatures in Western Australia’s Shark Bay to rise to levels so high that it negatively affected the survival and reproduction rates of the bay’s dolphin population, researchers with the University of Zurich wrote in a paper published April 1.
The high water temperatures caused negative effects up and down the food chain, from losses of habitat forming seagrass meadows, to mass deaths of invertebrate and fish communities. The Indo-Pacific bottlenose dolphin (Tursiops aduncus) that live in Shark Bay experienced a notable decline in female reproduction rates following the heatwave event. The researchers studied long-term data of hundreds of dolphins from 2007 to 2017 and found that the survival rate of these dolphins had declined by 12 percent after the heatwave of 2011. They also found that fewer calves were being born.
“The extent of the negative influence of the heatwave surprised us,” Sonja Wild, former Ph.D candidate at the University of Leeds and first author of the study said in a statement released by the university. “It is particularly unusual that the reproductive success of females appears to have not returned to normal levels, even after six years.”
Another notable observation is the fact that the heatwave didn’t have the same effect on all dolphin groups in the bay. Those dolphins that use sponges as a tool to help locate food in deep water were not as negatively affected as those dolphins that don’t use tools to help find food.
“Nevertheless, our work raises concerns that such sudden events might have quite negative long-term effects even in groups of marine mammals that are known to adapt usually well to novel environmental conditions,” Wild said.
According to the researchers, their data shows that marine heatwaves negatively affect organisms from lower levels, such as with seagrasses, all the way to the top of the food chain, such as with dolphins.
“Marine heatwaves are likely to occur more frequently in the future due to climate change,” study leader Michael Krützen, professor at the Department of Anthropology at UZH said. “This is worrying not only for the long-term prospects of marine mammal populations, but also for the entire oceanic ecosystems.”
An abstract of the study, “Long-term decline in survival and reproduction of dolphins following a marine heatwave,” can be read on the Current Biology website.