MIT scientists find first evidence that rivers form coral reef passes
In a paper published in the peer-reviewed journal Geophysical Research Letters, the MIT team described reef passes as "deep, navigable channels dissecting coral reefs around volcanic islands." These are basically wide channels that cut through the coral and serve as conduits for ocean water and nutrients to filter in and out.
As many reef passes are found to form near large island river basins, researchers had previously assumed a relationship existed between the two. However, the theory remained unproven until now.
The authors of the latest study showed "how coral reefs line up with where rivers funnel out from an island's coast." These water channels play a direct role as a freshwater body meets the sea, providing circulation throughout a reef and maintaining the health of corals by allowing saltwater and transporting key nutrients, a media release by MIT explained.
The study impacts scientists' understanding of how coral reefs form and function, as much discussion has been brewing about this symbiotic interaction in recent years.
MIT researchers focused on the Society Islands, a chain in the South Pacific Ocean around Tahiti and Bora Bora. However, the pandemic limited their ability to work onsite, needing to rely on satellite images and maps.
Lead study authors professor Taylor Perron and graduate student Megan Gillen found that "reef passes are deep channels cutting through reef barriers and flats that facilitate wave- and tide-driven circulation. These passes regulate flow between lagoon and ocean."
"It is well known that rivers discharging freshwater and sediment off islands affect reef structure and composition," study authors added. However, was there a direct connection between outlets of large island rivers and reef passes?
Thanks to geospatial analysis of the archipelago, the researchers discovered that river basins drain to parts of the reef, essentially creating an underwater highway. River erosion actually shapes these coral formations. Rivers running towards the ocean created these eroded depressions in the coastline over time.
The study authors identified two river-driven reef pass formation mechanisms: reef incision and reed encroachment. Incision refers to how "rivers cut passes into reefs exposed when the sea level is lower." Encroachment refers to where "old river channels on land are preserved as passes when sea level rises."
"Reefs migrate toward the islands as sea levels rise, trying to keep pace with changing average sea level," observed Gillen. The study further states that the results "show how rivers may support reef health over geologic timescales by enhancing water circulation between lagoons and oceans."
"A lot of discussion around rivers and their impact on reefs today has been negative because of human impact and the effects of agricultural practices," said Gillen. "This study shows the potential long-term benefits rivers can have on reefs, which I hope reshapes the paradigm and highlights the natural state of rivers interacting with reefs," she added
Now, with this knowledge proven, Gillen will be exploring how rivers could be engineered to promote circulation and reef health.
You can view the full study in the journal Geophysical Research Letters.
Hashtags
Try Our AI Features
Explore what Daily8 AI can do for you:
Comments
No comments yet...
Related Articles
Yahoo
9 hours ago
- Yahoo
Human Babies Aren't Supposed to Have 3 Parents—but Now They Can
"Hearst Magazines and Yahoo may earn commission or revenue on some items through these links." Here's what you'll learn when you read this story: The first babies with three biological parents were born out of a new technique to prevent mitochondrial disease. The nucleus of an egg fertilized in vitro was transferred into a donor egg without a nucleus, but with viable mitochondria. Eight healthy babies, including a set of twins, were born with low to undetectable levels of mitochondrial mutations. The only creatures known to conceive offspring from more than two parents are salamanders. Females from the genus Ambystoma (which are notoriously promiscuous) mate with up to three different males, and that DNA is then incorporated into what is known as a triploid genome in their offspring. Now a version of this has become possible in humans. It seems limb regeneration isn't the only way medical intervention can put humans on salamanders' level. Being born with three genomes is not a phenomenon that occurs naturally in Homo sapiens, but in an attempt to prevent certain genetic conditions caused by mutations in the mitochondria, scientists have found a way. Mitochondrial DNA or mtDNA is exclusively passed down from the maternal side. Dysfunction in the mitochondria can lead to metabolic diseases characterized by symptoms such as seizures, developmental delays, blindness, and loss of muscular function. Some can even be fatal. Mitochondrial diseases occur in about 1 in every 5,000 people. They were previously only preventable by using a donor egg or foregoing the conception of biological children altogether. This is why pediatric neurologist Bobby McFarland, of Newcastle University in the UK, led an experimental study that would reduce and potentially eliminate the risk of mitochondrial disease with a new method of in vitro fertilization. McFarland and his research team wanted see if removing the nucleus of an egg and placing it in a donor egg with viable mitochondria would result in healthy offspring. 'We found that pronuclear transfer, a form of mitochondrial donation, was effective in reducing the level of pathogenic mtDNA variant to substantially below the threshold for clinical disease in the offspring of women with homoplasmic (or high heteroplasmic) levels,' he said in a study recently published in the New England Journal of Medicine. When mitochondria are homoplasmic, all copies produced by cell division have mutations. Mutation levels vary in heteroplasmic mitochondria. Preimplantation genetic testing (PGT) can screen for these abonormalities, and women with homoplasmy or high levels of heteroplasmy can benefit from what is now known as pronuclear transfer. This involves eggs from both the mother and donor being fertilized with the father's sperm in vitro. Nuclei are then removed from both eggs after ten hours. Since the nucleus carries most genetic material and has no connection to mitochondrial disease, the mother's nucleus is implanted into the donor egg to take advantage of its mitochondria. While there is a chance that a few of the mother's mitochondria may end up in the embryo, it is unlikely to cause a debilitating disease. Levels of defective mitochondria in offspring conceived via pronuclear transfer were low enough to escape that fate. Eight pregnancies (including a set of twins) resulted from the experiment, and while there were a few minor health problems in the newborns, these were either treatable or corrected themselves. Not only were levels of heteroplasty low for the babies, but undetectable in five of them. Developmental progress also turned out to be normal. Though one baby had a form of infant epilepsy, and another had heart arrhythmia and hyperlipidemia, or high levels of fats and lipids in the blood, both of these conditions were treated and resolved. Whether the hyperlipidemia was even caused by mtDNA is uncertain, especially because the mother also had severe hyperlipidemia during her pregnancy. Though there was a chance that any of the mothers with pathogenic mtDNA had a higher risk of complications during pregnancy, which could possibly cause their children to have health issues, there is no proof for now. 'We are assessing, over the long term, the health and extent of heteroplasmy (if detectable) of the offspring,' McFarland and his team said. 'Indeed, the role of mitochondrial donation as a choice for women with a heritable pathogenic mtDNA variant will only be established with the availability of additional data.' You Might Also Like Can Apple Cider Vinegar Lead to Weight Loss? Bobbi Brown Shares Her Top Face-Transforming Makeup Tips for Women Over 50 Solve the daily Crossword
Yahoo
11 hours ago
- Yahoo
Motion cameras were set up in the jungles of Guatemala — and they captured something incredible
During a nasty summer heat wave — see: much of the US right now — water is a reliable source of relief. Where there are no rivers or lakes to swim in, we still might have swimming pools, sprinklers, and popsicles to keep ourselves cool. Wild animals don't have such luxuries. Bouts of extreme heat and drought — which are becoming more common and less predictable as global temperatures rise — can cause natural watering holes in many different types of ecosystems to dry up. And animals don't have a tap they can simply turn on. That leaves them with few places to hydrate and cool off, putting their lives, often already imperiled, at risk. But in some parts of the world, humans are offering help. In the jungles of northern Guatemala, which have been abnormally hot in recent years, environmental groups placed several large tubs of water in nature reserves. They refill them regularly, providing a reliable source of fresh water that animals can drink from or splash in, even when there's no rain. And luckily for us, they also put motion-activated cameras nearby to see which animals were using them. You might call them thirst traps. Courtesy of Wildlife Conservation Society 'The diversity of species using the water sources was amazing,' said Gabriela Ponce, head of Wildlife Conservation Society Guatemala, a group involved in the project with several others, including the local Guatemala NGO Foundation for Ecodevelopment and Conservation. The footage reveals a diverse cast of jungle characters, including those that are rarely seen, like jaguars and tapirs — large herbivores with distinct trunk-like noses. It also exposed some interesting animal behaviors, Ponce said. Researchers noticed that spider monkeys seemed to prefer drinking from raised water containers — perhaps so that they can quickly escape if predators approach, Ponce said. Wild animals are often more sensitive to environmental impacts than we are. They don't have technologies like air conditioning and water purification to survive all the ways in which we're altering the planet, from heating it up to filling it with pollution. And when climate disasters hit, the impacts are often devastating to wild animals, too. But there are simple ways to help wildlife cope with the world we've created for them, like putting out (clean) hummingbird feeders and bird baths or extinguishing invasive mosquitos that are spreading avian malaria. 'Artificial watering holes are not a permanent solution,' Rony García-Anleu, who leads biological research at Wildlife Conservation Society Guatemala, said in a press release. 'But they are a vital tool in helping wildlife adapt to increasingly unpredictable environmental conditions.' Solve the daily Crossword
Washington Post
16 hours ago
- Washington Post
Ancient river landscapes under Antarctica may may stabilize ice sheet
Landscapes left behind by ancient rivers and buried beneath the Antarctic ice may affect the rate of ice loss, researchers report in Nature Geoscience. The team used radio echo sounding, a technique that measures ice thickness using radar, to study the East Antarctic Ice Sheet between Princess Elizabeth Land and George V Land in Antarctica. Parts of the ice sheet are thought to be particularly susceptible to climate change because the land beneath it contains huge troughs that let warming ocean water reach the ice, causing rapid shrinking.
