Showing posts with label Marine Biology. Show all posts
Showing posts with label Marine Biology. Show all posts

Friday, May 20, 2022

New study reveals the global impact of debris on marine life

Dr Sarah Gall
Credit: University of Plymouth

Nearly 700 species of marine animal have been recorded as having encountered man-made debris such as plastic and glass, according to the most comprehensive impact study in more than a decade.

Researchers at Plymouth University found evidence of 44,000 animals and organisms becoming entangled in, or swallowing debris, from reports recorded from across the globe.

Plastic accounted for nearly 92 per cent of cases, and 17 per cent of all species involved were found to be threatened or near threatened on the IUCN Red List, including the Hawaiian monk seal, the loggerhead turtle and sooty shearwater.

In a paper, 'The impact of debris on marine life', published in Marine Pollution Bulletin, authors Sarah Gall and Professor Richard Thompson present evidence collated from a wide variety of sources on instances of entanglement, ingestion, physical damage to ecosystems, and rafting, where species are transported by debris.

Thursday, May 19, 2022

Mystery of seafloor metamorphosis unlocked

An adult tubeworm, in its tube, with its plume of tentacles extended.
Photo credit: Freckelton et al. 2022

Most bottom-dwelling marine invertebrate animals, such as sponges, corals, worms and oysters, produce tiny larvae that swim in the ocean prior to attaching to the seafloor and transforming into juveniles. A study published in the Proceedings of the National Academy of Sciences and led by University of Hawaiʻi at Mānoa researchers revealed that a large, complex molecule, called lipopolysaccharide, produced by bacteria is responsible for inducing larval marine tubeworms, Hydroides elegans, to settle to the seafloor and begin the complex processes of metamorphosis.

“This is a major milestone in understanding the factors that determine where larvae of bottom-living invertebrates settle and metamorphose,” said Michael Hadfield, senior author on the paper and emeritus professor in the UH Mānoa School of Ocean and Earth Science and Technology (SOEST). “It is the key to understanding how benthic (underwater) communities are established and maintained on all surfaces under salt water, that is, on 71% of Earth’s surface.”

Wednesday, May 18, 2022

At-Risk Sea Life in the Atlantic Needs Better Protection from an Increase in Shipping


Researchers at the University of Portsmouth have discovered that rates of shipping in the North East Atlantic area rose by 34 per cent in a five-year period.

Even more noticeable, and of major concern to scientists, is the rate of shipping growth in Marine Protected Areas. Analysis of vessel movements in these delicate environments shows an increase of 73 per cent in the same time period.

The report, which was published in Marine Pollution Bulletin, is the first detailed survey of shipping activity in the North East Atlantic. Researchers used data from over 530 million vessel positions recorded by Automatic identification Systems (AIS). They looked at the change in shipping between 2013 and 2017 across ten distinct vessel types.

In total the study area covered 1.1 million km2, including waters off Belgium, Denmark, France, Germany, Iceland, Ireland, The Netherlands, Norway, Portugal, Spain, and the UK.

Renewed monitoring effort is needed to ensure that protective measures are adequate to conserve species under threat in a changing environment.

Wednesday, May 11, 2022

International project aims to understand and protect endangered sea turtles

A hawksbill sea turtle (Eretmochelys imbricata)
Credit: Kate Charles, Ocean Spirits Inc

A partnership of organizations and universities in the UK and Grenada has launched a new project looking into the challenges and threats facing two endangered marine species.

Marine conservationists in the two countries will be working to understand more about hawksbill sea turtles (Eretmochelys imbricata) and green sea turtles (Chelonia mydas).

This will include using a variety of field techniques to fully appreciate their behaviors and habitats, and ultimately, the partners hope to develop a series of measures that can be used to support the sustainable conservation of the species now and in the future.

The research is being funded by the Oscar Montgomery Environmental Foundation (OMEF), a charity launched in 2020 as a legacy to a young man who was passionate about the marine environment.

He died, aged just 17, and the charity set up in his memory aims to support, advocate and raise awareness of environmental issues, largely marine, and support projects and research which work to conserve and enhance the global environment.

Saturday, May 7, 2022

Squid and Octopus Genome Studies Reveal How Cephalopods’ Unique Traits Evolved

The Hawaiian bobtail squid (Euprymna scolopes) is a model system for studying animal-bacterial symbiosis.
Credit: Tom Kleindinst

Squid, octopus, and cuttlefish – even to scientists who study them – are wonderfully weird creatures. Known as the soft-bodied or coleoid cephalopods, they have the largest nervous system of any invertebrate, complex behaviors such as instantaneous camouflage, arms studded with dexterous suckers, and other evolutionarily unique traits.

Now, scientists have dug into the cephalopod genome to understand how these unusual animals came to be. Along the way, they discovered cephalopod genomes are as weird as the animals are. Scientists from the Marine Biological Laboratory (MBL) in Woods Hole, the University of Vienna, the University of Chicago, the Okinawa Institute of Science and Technology and the University of California, Berkeley, reported their findings in two new studies in Nature Communications.

“Large and elaborate brains have evolved a couple of times,” said co-lead author Caroline Albertin, Hibbitt Fellow at the MBL. “One famous example is the vertebrates. The other is the soft-bodied cephalopods, which serve as a separate example for how a large and complicated nervous system can be put together. By understanding the cephalopod genome, we can gain insight into the genes that are important in setting up the nervous system, as well as into neuronal function.”

In Albertin et al., published this week, the team analyzed and compared the genomes of three cephalopod species – two squids (Doryteuthis pealeii and Euprymna scolopes) and an octopus (Octopus bimaculoides).

Only 10 vaquita porpoises survive, but species may not be doomed

Credit: Paula Olson/NOAA

The vaquita porpoise, the world’s smallest marine mammal, is on the brink of extinction, with 10 or fewer still living in Mexico’s Gulf of California, their sole habitat. But a genetic analysis by a team of UCLA biologists and colleagues has found that the critically endangered species remains relatively healthy and can potentially survive — if illegal “gillnet” fishing ceases promptly.

“Interestingly, we found the vaquita is not doomed by genetic factors, like harmful mutations, that tend to affect many other species whose gene pool has diminished to a similar point,” said Christopher Kyriazis, a UCLA doctoral student in ecology and evolutionary biology and a co–lead author of the research. “Outlawed fishing remains their biggest threat.”

The small porpoises, which range from 4 to 5 feet in length, often become entangled and die in the large mesh gillnets used by poachers hunting the totoaba, an endangered fish highly valued in some countries for its perceived medicinal properties. While Mexico has outlawed totoaba fishing and made the use of these nets in the vaquitas’ habitat illegal, many say the bans are not always enforced.

The researchers analyzed the genomes of 20 vaquitas that lived between 1985 and 2017 and conducted computational simulations to predict the species’ extinction risk over the next 50 years. They concluded that if gillnet fishing ends immediately, the vaquita has a very high chance of recovery, even with inbreeding. If, however, the practice continues, even moderately, the prospects of recovery are less optimistic.

Thursday, April 28, 2022

Unchecked global emissions on track to initiate mass extinction of marine life

Princeton University researchers report that unless greenhouse gas emissions are curbed, marine biodiversity could be on track to plummet to levels not seen since the extinction of the dinosaurs. The study authors modeled future marine biodiversity under projected climate scenarios and found that species such as dolphinfish (shown) would be imperiled as warming oceans decrease the ocean’s oxygen supply while increasing marine life’s metabolic demand for it. 
Credit: Evan Davis

As greenhouse gas emissions continue to warm the world’s oceans, marine biodiversity could be on track to plummet within the next few centuries to levels not seen since the extinction of the dinosaurs, according to a recent study in the journal Science by Princeton University researchers.

Princeton University researchers report that unless greenhouse gas emissions are curbed, marine biodiversity could be on track to plummet to levels not seen since the extinction of the dinosaurs. The study authors modeled future marine biodiversity under projected climate scenarios and found that species such as dolphinfish (shown) would be imperiled as warming oceans decrease the ocean’s oxygen supply while increasing marine life’s metabolic demand for it.

The paper’s authors modeled future marine biodiversity under different projected climate scenarios. They found that if emissions are not curbed, species losses from warming and oxygen depletion alone could come to mirror the substantial impact humans already have on marine biodiversity by around 2100. Tropical waters would experience the greatest loss of biodiversity, while polar species are at the highest risk of extinction, the authors reported.

Large bodies helped extinct marine reptiles with long necks swim, study finds

3D models of aquatic tetrapods
Credit: S. Gutarra Díaz

Scientists at the University of Bristol have discovered that body size is more important than body shape in determining the energy economy of swimming for aquatic animals.

This study, published today in Communications Biology, shows that big bodies help overcome the excess drag produced by extreme morphology, debunking a long-standing idea that there is an optimal body shape for low drag.

One important finding of this research is that the large necks of extinct elasmosaurs did add extra drag, but this was compensated for by the evolution of large bodies.

Tetrapods or ‘four-limbed vertebrates’, have repeatedly returned to the oceans over the last 250 million years, and they come in many shapes and sizes, ranging from streamlined modern whales over 25 meters in length, to extinct plesiosaurs, with four flippers and extraordinarily long necks, and even extinct fish-shaped ichthyosaurs.

Dolphins and ichthyosaurs have similar body shapes, adapted for moving fast through water producing low resistance or drag. On the other hand, plesiosaurs, who lived side by side with the ichthyosaurs in the Mesozoic Era, had entirely different bodies. Their enormous four flippers which they used to fly underwater, and variable neck lengths, have no parallel amongst living animals. Some elasmosaurs had really extreme proportions, with necks up to 20 feet (6 meters) long. These necks likely helped them to snap up quick-moving fish, but were also believed to make them slower.

Friday, April 8, 2022

Human activity ‘helped fuel’ red tide events, new study reveals

The study is just the beginning of discovering the effects of human activity on red tide blooms.
Credit: File photo/UF

In a new study that is the first to explain what some have long suspected, researchers found that human activity helps sustain and intensify naturally occurring red tide blooms in Southwest Florida.

Conducted by researchers at the University of Florida, Sanibel-Captiva Conservation Foundation and Sarasota Bay Estuary Program, the study found that while a combination of factors contributes to red tide blooms, human activity has played a consistent role in intensifying them during the past decade.

The researchers linked blooms in Charlotte Harbor and surrounding coastal areas to nitrogen inputs from the Caloosahatchee River, Lake Okeechobee and areas upstream of the lake. The study was published in the journal Science of the Total Environment.

“While red tide blooms develop naturally, we took a long view and found evidence that human activity has helped fuel coastal blooms in this estuary to varying extents between 2012 and 2021,” said Miles Medina, lead author of the study and a research scientist at UF’s Center for Coastal Solutions.

Determining what contributes to red tide intensification has been a priority for coastal states, as the harmful toxins these blooms create affect humans and sea and land creatures alike.

Thursday, April 7, 2022

Under Ocean Acidification, Embryos of a Key Forage Fish Struggle to Hatch

This photo shows sand lance embryos that have and have not hatched. Sand lance have trouble hatching at future ocean CO2 levels
Credit: Emma Cross.

When carbon is emitted into the atmosphere, about a quarter of it is absorbed by the earth’s oceans. As the oceans serve as a massive ‘sink’ for carbon, there are changes to the water’s pH – a measure of how acidic or basic water is. As oceans absorb carbon, their water becomes more acidic, a process called ocean acidification (OA). For years, researchers have worked to understand what effect this could have on marine life.

While most research so far shows that fish are fairly resilient to OA, new research from UConn, the University of Washington, the National Oceanic and Atmospheric Administration (NOAA), and Southern Connecticut State University, shows that an important forage fish for the Northwest Atlantic called sand lance is very sensitive to OA, and that this could have considerable ecosystem impacts by 2100. The team’s findings have just been published in Marine Ecology Progress Series.

Sand lance spawn in the winter months in offshore environments that tend to have stable, low levels of CO2, explains UConn Department of Marine Sciences researcher and lead author Hannes Baumann.

“Marine organisms are not living in a uniform ocean,” Baumann says. “In near shore environments, large CO2 fluctuations between day and night and between seasons are the norm, and the fish and other organisms are adapted to this variability. When we stumbled upon sand lances, we suspected they're different. We thought that a fish that lives in a more open-ocean offshore environment might be more sensitive than the near-shore fish because there’s just much less variability.”

Tuesday, April 5, 2022

Squid recorded color-matching substrate for the first time

A species of oval squid (locally known as Shiro-ika) from Okinawa is being cultured at OIST’s Marine Science Station. This animal exhibited amazing camouflaging abilities never before recorded in squid. Credit: Ryuta Nakajima / OIST.

While octopus and cuttlefish are famous for their use of camouflage to match the color of the substrate, a third type of cephalopod—the squid—has never been reported displaying this ability. Now, in a study published in Scientific Reports, scientists from the Physics and Biology Unit at the Okinawa Institute of Science and Technology Graduate University (OIST) have shown that squid can and will camouflage to match a substrate as a way of avoiding predators. This work opens up research avenues on how squid see and perceive the world around them. Furthermore, it sheds light on their behavior, and thus could go on to inform conservation initiatives.

“Squid usually hover in the open ocean but we wanted to find out what happens when they move a bit closer to a coral reef or if they’re chased by a predator to the ocean floor,” explained one of the three first authors, Dr. Ryuta Nakajima, OIST visiting researcher. “If substrate is important for squid to avoid predation than that indicates that increases or decreases in squid populations are even more tied to the health of coral reef than we thought.”

Previous studies on cephalopod camouflage have mostly been conducted on cuttlefish and octopus. Squids, as an animal that tends to live in the open ocean, are notoriously hard to keep in captivity and so have been avoided for this kind of research. But, since 2017, the scientists in the OIST’s Physics and Biology Unit have been culturing a species of oval squid in captivity.

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