Jaguars robust to climate extremes but lack of food threatens species

Researchers track climate change scenarios for Amazonian wild cats

QUEENSLAND UNIVERSITY OF TECHNOLOGY

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VIDEO: QUT RESEARCHERS LEAD A WORLD-FIRST INVESTIGATION INTO THE CHANCES OF WILD JAGUARS SURVIVING CLIMATE EXTREMES WITH SIX SCENARIOS MODELLING THE BEHAVIOUR, MATING, BIRTHS OF CUBS, COMPETITION, ILLEGAL HUNTING, DEATH FROM... view more 

CREDIT: QUT MEDIA

A new QUT-led study has found wild jaguars in the Amazon can cope with climate extremes in the short-term, but numbers will rapidly decline if weather events increase in frequency, diminishing sources of food.

Distinguished Professor Kerrie Mengersen and Professor Kevin Burrage led a team of researchers in a world-first investigation of the big cat's chances of survival.

The new research results have been published in Ecology and Evolution.

The jaguar (Panthera onca) is the dominant predator in Central and South America and is considered a near-threatened species by the International Union Conservation Nature.

Research main points: -

• Results are concerning for future viability of jaguar populations in Peruvian Amazon.
• Stochastic statistical temporal model of jaguar abundance considers six population scenarios and estimates of prey species.
• Jaguar diet includes white lipped peccary, collared peccary, red brochet deer, white tailed deer, agouti, paca and armadillo.
• Species exhibit some robustness to extreme drought and flood, but repeated exposure can result in rapid decline.
• Predictions show species can recover- at lower numbers - if there are periods of benign climate patterns.
• Modelling provides framework to evaluate complex ecological problems using sparse information sources.

CAPTION

Infographic describing QUT investigation on the impact of climate change on jaguars.

Professor Mengersen said the Pacaya Semiria Reserve covers 20,800 km2 in the Loreto region of the Peruvian Amazon, comprised of mostly primary forest.

"Estimates of jaguar numbers are difficult to achieve because the big cats are cryptic by nature, are not always uniquely identifiable, and their habitat can be hostile to humans," Professor Mengersen said.

The project drew on information gathered during a 2016 trip to the remote reserve, as well as a census study based on camera traps and scat analysis, jaguar ecology, and an elicitation study of Indigenous rangers in the Pacaya Samiria National Reserve.

Six jaguar population scenarios were analysed mapping the jungle creature's solitary behaviour, mating, births of cubs at certain times of the year, competition, illegal hunting, death from starvation and availability of key prey.

Professor Kevin Burrage cautioned the predicted results for the jaguars in the long-term were concerning.

"Our results imply that jaguars can cope with extreme drought and flood, but there is a very high probability that the population will crash if the conditions are repeated over short time periods. These scenarios are becoming more likely due to climate change," he said.

"The declines may be further exacerbated by hunting of both jaguars and their prey, as well as loss of habitat through deforestation."

Professor Burrage said scenario 1 estimated the jaguar population at 600-700 assuming stable prey availability while scenario 6 was an extreme case with drought and flood occurring every other year.

"In this worst-case scenario, prey levels could not recover, and jaguar populations was predicted to drop to single digits in 30 years' time," Professor Burrage said.

CAPTION

QUT's Distinguished Professor Kerrie Mengersen led a team of researchers in a world-first investigation of the big cat's chances of survival with the findings published in Ecology and Evolution.

In addition to Professors Mengersen and Burrage, researchers involved in the study included Professor Erin Peterson, Professor Tomasz Bednarz, Dr Pamela Burrage, Dr Julie Vercelloni and June Kim based at the ARC Centre of Excellence for Mathematical and Statistical Frontiers, and Dr Jacqueline Davis of the University of Cambridge and the Vrije Universiteit of Amsterdam.

A pdf of the journal paper is available.

Imagery available via Dropbox.

TPU scientists develop eco-friendly hydrogel for agriculture

TOMSK POLYTECHNIC UNIVERSITY

Research News

 

Scientists of Tomsk Polytechnic University, in cooperation with the Czech colleagues have developed a new hydrogel for agriculture. It is meant to retain moisture and fertilizers in soil. The difference of the new hydrogel from other formulations is that it is made entirely of natural components and degrades in soil into nontoxic products to humans, animals, and plants. The research results are published in the Journal of Cleaner Production (IF: 7, 246; Q1).

Hydrogels are used in agriculture and forestry to retain moisture in soil, which directly affects germination. They are also used in combination with fertilizers as hydrogels reduce volatilization of fertilizers and therefore control fertilizer release.

"Due to the hydrogels, plants require less watering and fertilization. On the one hand, it is important for fresh water conservation on the planet, on the other hand, it reduces the harmful effect of fertilizers to the soil. Most of the hydrogels available on the market are made of polyacrylamide and polyacrinolintrile. They are not fully biodegradable, that is why they are considered potential soil contaminants. Even though the components themselves are not toxic, their commercial formulations contain residual amounts of acrylamide, which is a neurotoxic and carcinogen substance. We used whey protein and alginic acid as primary components in our research work. These are affordable, natural and completely non-toxic components. This is the main advantage of our hydrogel," Antonio Di Martino, one of the article authors, associate professor of the TPU Research School of Chemistry & Applied Biomedical Sciences, says.

The process of obtaining the hydrogel suggested by the authors of the research is simple: the primary components must be mixed in a solution, dried, and compressed into a tablet. In contact with liquids, the substance swells and becomes gel-like.

"We also added urea in the mixture which is a well-known fertilizer. Over time, the hydrogel degrades in soil gradually and evenly releasing the fertilizer. Moreover, the hydrogel itself degrades into carbon and nitrogen over time, while nitrogen is a widely used macronutrient in agriculture and an essential structural material for plants. The laboratory experiments showed that the hydrogel can be used a few more times after a full release of moisture," Antonio Di Martino notes.

In the future, the scientists will continue experimenting and searching for new materials for a controlled application of fertilizers in soil.

###

The scientists from Tomas Bata University in Zlín (the Czech Republic), Dairy Research Institute (the Czech Republic), and Research Institute for Soil and Water Conservation (the Czech Republic) took part in the research project.

An escape route for seafloor methane

Leakage from frozen layers was a puzzle, but a new study shows how the potent greenhouse gas breaks through icy barriers.

MASSACHUSETTS INSTITUTE OF TECHNOLOGY

Research News

 

Methane, the main component of natural gas, is the cleanest-burning of all the fossil fuels, but when emitted into the atmosphere it is a much more potent greenhouse gas than carbon dioxide. By some estimates, seafloor methane contained in frozen formations along the continental margins may equal or exceed the total amount of coal, oil, and gas in all other reservoirs worldwide. Yet, the way methane escapes from these deep formations is poorly understood.

In particular, scientists have been faced with a puzzle. Observations at sites around the world have shown vigorous columns of methane gas bubbling up from these formations in some places, yet the high pressure and low temperature of these deep-sea environments should create a solid frozen layer that would be expected to act as a kind of capstone, preventing gas from escaping. So how does the gas get out?

A new study helps explain how and why columns of the gas can stream out of these formations, known as methane hydrates. Using a combination of deep-sea observations, laboratory experiments, and computer modeling, researchers have found phenomena that explain and predict the way the gas breaks free from the icy grip of a frozen mix of water and methane. The findings are reported today in the journal PNAS, in a paper by Xiaojing (Ruby) Fu SM '15, PhD '17, now at the University of California at Berkeley; Professor Ruben Juanes at MIT; and five others in Switzerland, Spain, New Mexico, and California.

Surprisingly, not only does the frozen hydrate formation fail to prevent methane gas from escaping into the ocean column, but in some cases it actually facilitates that escape.

Early on, Fu saw photos and videos showing plumes of methane, taken from a NOAA research ship in the Gulf of Mexico, revealing the process of bubble formation right at the seafloor. It was clear that the bubbles themselves often formed with a frozen crust around them, and would float upward with their icy shells like tiny helium balloons.

Later, Fu used sonar to detect similar bubble plumes from a research ship off the coast of Virginia. "This cruise alone detected thousands of these plumes," says Fu, who led the research project while a graduate student and postdoc at MIT. "We could follow these methane bubbles encrusted by hydrate shells into the water column," she says. "That's when we first knew that hydrate forming on these gas interfaces can be a very common occurrence."

But exactly what was going on beneath the seafloor to trigger the release of these bubbles remained unknown. Through a series of lab experiments and simulations, the mechanisms at work gradually became apparent.

Seismic studies of the subsurface of the seafloor in these vent regions show a series of relatively narrow conduits, or chimneys, through which the gas escapes. But the presence of chunks of gas hydrate from these same formations made it clear that the solid hydrate and the gaseous methane could co-exist, Fu explains. To simulate the conditions in the lab, the researchers used a small two-dimensional setup, sandwiching a gas bubble in a layer of water between two plates of glass under high pressure.

As a gas tries to rise through the seafloor, Fu says, if it's forming a hydrate layer when it hits the cold seawater, that should block its progress: "It's running into a wall. So how would that wall not be preventing it from continuous migration?" Using the microfluidic experiments, they found a previously unknown phenomenon at work, which they dubbed crustal fingering.

If the gas bubble starts to expand, "what we saw is that the expansion of the gas was able to create enough pressure to essentially rupture the hydrate shell. And it's almost like it's hatching out of its own shell," Fu says. But instead of each rupture freezing back over with the reforming hydrate, the hydrate formation takes place along the sides of the rising bubble, creating a kind of tube around the bubble as it moves upward. "It's almost like the gas bubble is able to chisel out its own path, and that path is walled by the hydrate solid," she says. This phenomenon they observed at small scale in the lab, their analysis suggests, is also what would also happen at much larger scale in the seafloor.

That observation, she said, "was really the first time we've been aware of a phenomenon like this that could explain how hydrate formation will not inhibit gas flow, but rather in this case, it would facilitate it," by providing a conduit and directing the flow. Without that focusing, the flow of gas would be much more diffuse and spread out.

As the crust of hydrate forms, it slows down the formation of more hydrate because it forms a barrier between the gas and the seawater. The methane below the barrier can therefore persist in its unfrozen, gaseous form for a long time. The combination of these two phenomena -- the focusing effect of the hydrate-walled channels and the segregation of the methane gas from the water by a hydrate layer -- "goes a long way toward explaining why you can have some of this vigorous venting, thanks to the hydrate formation, rather than being prevented by it," says Juanes.

A better understanding of the process could help in predicting where and when such methane seeps will be found, and how changes in environmental conditions could affect the distribution and output of these seeps. While there have been suggestions that a warming climate could increase the rate of such venting, Fu says there is little evidence of that so far. She notes that temperatures at the depths where these formations occur -- 600 meters (1,900 feet) deep or more -- are expected to experience a smaller temperature increase than would be needed to trigger a widespread release of the frozen gas.

Some researchers have suggested that these vast undersea methane formations might someday be harnessed for energy production. Though there would be great technical hurdles to such use, Juanes says, these findings might help in assessing the possibilities.

"The problem of how gas can move through the hydrate stability zone, where we would expect the gas to be immobilized by being converted to hydrate, and instead escape at the seafloor, is still not fully understood," says Hugh Daigle, an associate professor of petroleum and geosystems engineering at the University of Texas at Austin, who was not associated with this research. "This work presents a probable new mechanism that could plausibly allow this process to occur, and nicely integrates previous laboratory observations with modeling at a larger scale."

"In a practical sense, the work here takes a phenomenon at a small scale and allows us to use it in a model that only considers larger scales, and will be very useful for implementing in future work," Daigle says.

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The research team included Joaquin Jimenez-Martinez at the Swiss Federal Institute of Aquatic Science and Technology; Than Phon Nguyen, William Carey and Hari Vinaswanathan at Los Alamos National Laboratory; and Luis Cueto-Felgueroso at the Technical University of Madrid. The work was supported by the U.S. Department of Energy.

Written by David L. Chandler, MIT News Office

Caribbean coral reefs under siege from aggressive algae

An aggressive, golden-brown, crust-like alga is rapidly overgrowing shallow reefs, taking the place of coral that was damaged by extreme storms and exacerbating the damage caused by human activity

CARNEGIE INSTITUTION FOR SCIENCE

Research News

 

IMAGE: ORANGE PEYSSONNELID ALGAL CRUSTS SPREADING OVER A LOBE OF ORBICELLA ANNULARIS AT 14-METER DEPTH ON THE TEKTITE REEF ON THE SOUTHERN SHORE OF ST. JOHN, U.S. VIRGIN ISLANDS. view more 

CREDIT: IMAGE COURTESY OF PETER EDMUNDS.

Baltimore, MD--Human activity endangers coral health around the world. A new algal threat is taking advantage of coral's already precarious situation in the Caribbean and making it even harder for reef ecosystems to grow.

Just-published research in Scientific Reports details how an aggressive, golden-brown, crust-like alga is rapidly overgrowing shallow reefs, taking the place of coral that was damaged by extreme storms and exacerbating the damage caused by ocean acidification, disease, pollution, and bleaching.

For the past four years, the University of Oxford's Bryan Wilson, Carnegie's Chen?Ming Fan, and California State University Northridge's Peter Edmunds have been studying the biology and ecology of peyssonnelid algal crusts, or PAC, in the U.S. Virgin Islands, which are out-competing coral larvae for limited surface space and then growing over the existing reef architecture, greatly damaging these fragile ecosystems.

"This alga seems to be something of an ecological winner in our changing world," described lead author Wilson, noting that the various other threats to coral communities make them more susceptible to the algal crusts.

Edmunds first took note of the crusts' invasive growth in the wake of category 5 hurricanes Irma and Maria when they were rapidly taking over spaces that had been blasted clean by the storms.

Corals are marine invertebrates that build large exoskeletons from which reefs are constructed. To grow new reef structures, free-floating baby corals first have to successfully attach to a stable surface. They prefer to settle on the crusty surface created by a specific type of friendly algae that grows on the local rocks. These coralline crustose algae, or CCA, acts as guideposts for the coral larvae, producing biochemical signals along with their associated microbial community, which entice the baby coral to affix itself.

What puzzled the researchers is that both the destructive PAC and the helpful CCA grow on rocks and create a crust, but PAC exclude coral settlement and CCA entices it. What drives this difference?

The team set out to determine how the golden-brown PAC affects Caribbean coral reefs, and found that the PAC harbors a microbial community that is distinct from the one associated with CCA, which is known to attract corals.

"These PAC crusts have biochemical and structural defenses that they deploy to deter grazing from fish and other marine creatures," explained Fan. "It is possible that these same mechanisms, which make them successful at invading the marine bio-space, also deter corals."

More research is needed to elucidate the tremendous success that the algal crusts are having in taking over Caribbean reef communities and to look for ways to mitigate the risk that they pose.

"There is a new genomic and evolutionary frontier to explore to help us understand the complexity of organismal interactions on the reef, both mutualistic and antagonistic," added Fan.

Edmunds concluded: "The coral and their ecosystem are so fragile as it is. They are under assault by environmental pollution and global warming. We have made their lives so fragile, yet they are sticking in there. And now this gets thrown into the mix. We don't know if this is the straw that breaks the camel's back, but we need to find out."

###

This work was funded by a Long Term Research in Environmental Biology grant and a Rapid Response Research grant from the U.S. National Science Foundation.

Research was completed under permits issued by the Virgin Islands National Park.

The Carnegie Institution for Science (carnegiescience.edu) is a private, nonprofit organization headquartered in Washington, D.C., with three research divisions throughout the U.S. Since its founding in 1902, the Carnegie Institution has been a pioneering force in basic scientific research. Carnegie scientists are leaders in plant biology, developmental biology, astronomy, materials science, global ecology, and Earth and planetary science.

UN to issue first-ever global report on harmful algal blooms

After 7 years' work, 100+ experts in 112 countries deliver 1st global assessment of HABs, synthesizing three decades of data

UNESCO INTERGOVERNMENTAL OCEANOGRAPHIC COMMISSION

Research News

 

IMAGE: MORE THAN 100 SCIENTISTS IN 112 COUNTRIES CONTRIBUTED TO A SYNTHESIS AND ANALYSIS OF HARMFUL ALGAL BLOOM DATA GATHERED FROM 1985 TO 2018 -- A FIRST-EVER BIG DATA APPROACH TO... view more 

CREDIT: MELVIL JAPAN

A seven-year analysis of almost 10,000 Harmful Algal Blooms (HAB) events worldwide over three decades will be published by the HAB Programme of UNESCO's Intergovernmental Oceanographic Commission.

More than 100 scientists in 112 countries contributed to the synthesis and analysis of HAB data gathered from 1985 to 2018 -- a first-ever big data approach to detecting changes in the costly phenomenon's global distribution, frequency, and intensity.

The authors detail the health and economic damages caused by harmful microalgae, including:

• Bioaccumulation of toxins in seafood (the most dominant HAB problem, broken down by both region and by algae species)

• Toxic or non-toxic microalgae blooms causing discoloured water, scum, mucilage or foam, harming tourism and/or fisheries

• Mass fish kills, including in aquaculture operations

• High biomass, causing closures of e.g. beaches or desalination plants

The researchers also examine whether and how rising marine resource exploitation and other factors affect HAB events.

The work assesses the occurrence of toxin-producing and other harmful microalgae, and the status and probability of change in HAB frequencies, intensities, and range resulting from environmental change at the local and global scale.

Publication of the key findings in a prominent journal will be followed by a complete set of 13 papers to be published in a special edition of Harmful Algae.

Databases mined

Thousands of microalgae species form the foundation of aquatic food chains, help control atmospheric CO2 levels, and produce roughly half of the world's oxygen.

The troublemakers are approximately 200 species that can produce potent toxins or cause harm through their sheer biomass, plus a similar number of non-toxic species that can harm fish gills, impair the beauty of the sea with strange colours, scums and foams, or deplete oxygen.

The study involved mining the global Harmful Algae Event Database (HAEDAT), consisting of 9,503 events with one or more impacts on human society, together with the Ocean Biodiversity Information System (OBIS), which contains 7 million microalgal records including 289,668 toxic algal species occurrences.

Due to differences in the levels of monitoring worldwide, trends within the HAEDAT database were examined regionally and corrected for sampling effort using OBIS phytoplankton species records as a proxy.

The work creates the first-ever baseline to facilitate future tracking and detection of changes in the world's HAB problems, and to help manage the problems in future.

Three key public databases

The Harmful Algal Event Database (HAEDAT, http://haedat.iode.org)

The only existing database of information about harmful algal events from around the world, summarized into 'events' associated with a management action or negative economic / ecological impact. Includes cases of non-toxic water discolorations, mucilage, anoxia or other damage to fish.

HABMAP-OBIS (http://www.iobis.org):

A database on the geographic range of harmful algal species

HAEDAT and OBIS are both components of the IOC International Oceanographic Data and Information Exchange Programme (IODE).

The IOC-UNESCO Taxonomic Reference List of Harmful Microalgae

Includes formally accepted names of 150+ planktonic or benthic microalgae that have been proven to produce toxins. The number of species in the list has doubled over the years.

The work will help future researchers determine:

1. The distribution of HAB species, HAB events, and toxins globally

2. How the geographic distribution, characteristic, frequency and intensity of HABs are changing and if these changes are attributable to global change

3. How climate change and other factors alter the impacts of HABs -- on human health, ecosystems, economics, food and water security

With more than 100 expert contributors from 112 countries, the work is piloted by 18 principal authors from 14 countries (including two from Australia, two from France, three from the USA):

· Gustaaf M. Hallegraeff, University of Tasmania, Australia

· Donald M. Anderson, Woods Hole Oceanographic Institution, USA

· Catherine Belin, IFREMER, France

· Marie-Yasmine Bottein, Ecotoxicologie et Développement Durable expertise, France

· Eileen Bresnan, Marine Scotland, UK

· Mireille Chinain, Institut Louis Malardé-UMR241, Tahiti

· Henrik Enevoldsen, Intergovernmental Oceanographic Commission of UNESCO, University of Copenhagen, Denmark

· Mitsunori Iwataki, University of Tokyo, Japan

· Cynthia H. McKenzie, Fisheries and Oceans Canada, Canada

· Inés Sunesen, CONICET - UNLP, Argentina

· Grant C. Pitcher, University of Cape Town, South Africa

· Pieter Provoost, Intergovernmental Oceanographic Commission of UNESCO, Oostende, Belgium

· Anthony Richardson, CSIRO Oceans and Atmosphere, and University of Queensland, Australia

· Laura Schweibold, Institut Universitaire Européen de la Mer, France

· Patricia A. Tester, Ocean Tester, USA

· Vera L. Trainer, National Oceanic and Atmospheric Administration, USA

· Aletta T. Yñiguez, University of the Philippines, Philippines

· Adriana Zingone, Stazione Zoologica Anton Dohrn, Italy

"The most frequently asked questions about Harmful Algal Blooms (HABs) are if they are increasing and expanding, and what are the mechanisms behind observed trends," the authors say.

"Indeed a global expansion of HABs and its causes have long been debated. Eutrophication, human-mediated introduction of alien harmful species, climatic variability, and aquaculture have all been mentioned as possible causes of an expansion and intensification of HABs. Our research sheds an authoritative light on the problem and will help guide responses to it for decades to come."

The IOC Intergovernmental Panel on HABs began the Global HAB Status Report in 2013.

The work is linked with the International Panel on Climate Change (IPCC) reporting mechanism, which increasingly is focusing on the biological impacts of climate change.

IOC UNESCO project partners include the International Atomic Energy Agency (IAEA), the International Council for Exploration of the Sea (ICES), the North Pacific Marine Science Organization (PICES) and the International Society for the Study of Harmful Algae (ISSHA). The initiative receives financial support from the Government of Flanders/FUST-DIPS.

Interested media and other parties may apply for advance, embargoed access to the papers, approximately one week prior to publication. Please email tc@tca.tc with the subject line: Advance access, UN HAB report

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About the HAB Programme: https://bit.ly/3l44mUY

The Intergovernmental Panel on Harmful Algal Blooms (IOC-IPHAB), part of the Intergovernmental Oceanographic Commission of UNESCO, initiated the development of the Global HAB Status Report in Paris in April 2013, developed with the support of the Government of Flanders within the IOC International Oceanographic Data and Information Exchange (IODE) Programme, which manages both the Harmful Algae Event Data Base (HAEDAT) and the Ocean Biodiversity Information System (OBIS). Partners include ICES, PICES and IAEA.

OBIS focuses on the global distribution of all marine species including those HAB species that are toxic to humans and fish as covered by the IOC-UNESCO Taxonomic Reference list of Harmful MicroAlgae (a subset of the World Register of Marine Species), while HAEDAT holds information specifically on the HAB events that have adversely impact on human society, whether by high biomass (clogging of fishing nets, beach closures), aquaculture fish kills, or seafood toxin events leading to shellfish farm closures, human poisonings or even death.

Plastic contaminants harm sea urchins

UNIVERSITY OF EXETER

Research News

 

IMAGE: DEVELOPING SEA URCHIN LARVAE ARE AFFECTED BY CHEMICALS FROM MARINE MICROPLASTICS. LEFT - NOT TREATED. RIGHT - TREATED. view more 

CREDIT: EVA JIMENEZ-GURI

Plastics in the ocean can release chemicals that cause deformities in sea urchin larvae, new research shows.

Scientists soaked various plastic samples in seawater then removed the plastic and raised sea urchin embryos in the water.

The study, led by the University of Exeter, found that urchins developed a variety of abnormalities, including deformed skeletons and nervous systems.

These abnormalities were caused by chemicals embedded in the plastics leaching out into the water, rather than the plastics themselves.

The plastic-to-water ratio in the study would only be seen in severely polluted places, but the findings raise questions about the wider impact of plastic contaminants on marine life.

"We are learning more and more about how ingesting plastic affects marine animals," said Flora Rendell-Bhatti, of the Centre for Ecology and Conservation on Exeter's Penryn Campus in Cornwall.

"However, little is known about the effects of exposure to chemicals that leach into the water from plastic particles.

"This study provides evidence that contamination of the marine environment with plastic could have direct implications for the development of larvae, with potential impacts on wider ecosystems.

"Our work contributes to the growing evidence that we all need to help reduce the amount of plastic contamination released into our natural environment, to ensure healthy and productive ecosystems for future generations."

Dr Eva Jimenez-Guri, also of the Centre for Ecology and Conservation, added: "Many plastics are treated with chemicals for a variety of purposes, such as making them mouldable or flame retardant.

"If such plastics find their way to the oceans, these chemicals can leach out into the water.

"Plastics can also pick up and transport chemicals and other environmental contaminants, potentially spreading them through the oceans."

The study used pre-production "nurdles" (pellets from which most plastics are made) from a UK supplier, and also tested nurdles and "floating filters" (used in water treatment) found on beaches in Cornwall, UK.

For the tests, each plastic type was soaked in seawater for 72 hours, then the plastic was removed.

Analysis of the water showed all samples contained chemicals known to be detrimental to development of animals, including polycyclic aromatic hydrocarbons and polychlorinated biphenyls.

Water from the different kinds of plastic affected urchin development in slightly different ways, though all sample types led to deformity of skeletons and nervous systems, and caused problems with gastrulation (when embryos begin to take shape).

The study also raised urchin embryos in water that had contained "virgin" polyethylene particles that had not been treated with additive chemicals or collected any environmental pollutants.

These urchins developed normally, suggesting that abnormalities observed in other samples were caused by industrial additives and/or environmentally adsorbed contaminants - rather than the base plastics themselves.

Nurdles and floating filters are not waste products, so they are not deliberately discarded, but the study highlights the importance of preventing their accidental release.

The researchers say most plastics may have similar effects as those in the study, so the findings emphasise the importance of finding alternatives to replace harmful additives, and reducing overall marine plastic pollution.

CAPTION

The skeleton (green) and nervous system (magenta) of sea urchin larvae are affected by chemicals from microplastics. Left - not treated. Right - treated.

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The study team included the Stazione Zoologica Anton Dohrn (Naples, Italy) and the Institute of Oceanology at the Polish Academy of Sciences (Sopot, Poland).

It was funded by the European Union's Horizon 2020 programme and the Natural Environment Research Council.

The paper, published in the journal Environmental Pollution, is entitled: "Developmental toxicity of plastic leachates on the sea urchin Paracentrotus lividus."

Even razor clams on sparsely populated Olympic Coast can't escape plastics, study finds

PORTLAND STATE UNIVERSITY

Research News

 

IMAGE: RESEARCHERS FOUND MICROPLASTICS IN PACIFIC RAZOR CLAMS ON WASHINGTON'S SPARSELY POPULATED OLYMPIC COAST -- PROOF, THEY SAY, THAT EVEN IN MORE REMOTE REGIONS, COASTAL ORGANISMS CAN'T ESCAPE PLASTIC CONTAMINATION. view more 

CREDIT: BRITTA BAECHLER | PORTLAND STATE UNIVERSITY

Portland State University researchers and their collaborators at the Quinault Indian Nation and Oregon State University found microplastics in Pacific razor clams on Washington's sparsely populated Olympic Coast -- proof, they say, that even in more remote regions, coastal organisms can't escape plastic contamination.

Microplastics are pieces of plastic smaller than 5 millimeters that are either intentionally produced at that size, or break down from synthetic clothing, single-use plastic items, or other products. These particles enter the environment and pervade freshwater and marine environments, soils and even the air we breathe.

Britta Baechler, the study's lead author and a recent graduate of PSU's Earth, Environment and Society doctoral program, analyzed the concentrations of microplastics in razor clams collected from eight beaches along the Washington coast and, after surveying recreational clam harvesters,estimated the annual microplastic exposure of those who eat them.

The Pacific razor clam is one of the most sought-after shellfish in Washington. The state's Department of Fish and Wildlife said that during a recent season, the recreational razor clam fishery saw more than 280,000 digger trips with diggers harvesting 4 million clams for the season. It's also a key first food, cultural resource, and vital source of income for members of the Quinault Indian Nation.

During the study, a total of 799 suspected microplastics were found in the 138 clam samples, 99% of which were microfibers. On average, clams had seven pieces of plastic each.

Clams from Kalaloch Beach, the northernmost site near the mouth of Puget Sound, contained significantly more microplastics than clams from the other seven sites. Though the study did not explore the reasons behind this, Baechler noted that there were no major differences in land cover types between Kalaloch and the other sites, but Kalaloch is the closest in proximity of all sites to the densely populated Seattle metro area.

Baechler's team compared whole clams -- minimally processed as if being consumed by an animal predator -- and cleaned clams -- gutted, cleaned of sand debris and grit, and prepared as if being eaten by a person. They found that in thoroughly cleaned clams, the amount of microplastics was reduced by half.

Baechler said this bodes better for people -- 88% percent of the survey respondents reported cleaning clams before eating them -- than for ocean predators that aren't afforded the luxury of cleaning clams prior to consumption.

Surveys of 107 recreational harvesters determined the average number of razor clams consumed per meal and the number of meals containing clams each year. Combining consumption information with the average number of microplastics per clam, the researchers estimated Olympic Coast razor clam harvester-consumers were exposed to between 60 and 3,070 microplastics per year from razor clams for those who thoroughly cleaned their clams before eating them, or between 120 and 6,020 microplastics a year for those who ate them whole without removing the guts, gills or other organs.

"We don't know the exact human health impacts of microplastics we inevitably ingest through food and beverages," said Baechler, who now works as an ocean plastics researcher at Ocean Conservancy. "Our estimates of microplastic exposure from this single seafood item are, for context, far lower than what we likely take in from inhalation, drinking bottled water and other sources, but no amount of plastic in our marine species or seafood items is desirable."

Baechler and Elise Granek, a professor of environmental science at PSU, said that everyone has a role to play in reducing plastic pollution in the marine environment -- from plastic producers and product designers who can develop effective upstream pollution control solutions to consumers who can make substitutions in their daily lives to reduce their plastic footprints.

"We all have become dependent on plastics for our clothing and packaging, and the more plastic we use, the more likely it's going to end up in our drinking water, our food and our air," Granek said. "All of us have a responsibility to do what we can to limit the amount of plastic that we're using."

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The study's findings were published in the journal Frontiers in Marine Science. Co-authors include Granek; Scott Mazzone, marine and shellfish biologist for the Quinault Indian Nation; Max Nielsen-Pincus, associate professor of environmental science at PSU; and Susanne Brander, assistant professor of fisheries and wildlife at Oregon State University.

Guam's most endangered tree species reveals universal biological concept

UNIVERSITY OF GUAM

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IMAGE: UNIVERSITY OF GUAM RESEARCH ASSOCIATE BENJAMIN DELOSO EXAMINES A BI-PINNATELY COMPOUND LEAF OF GUAM'S FLAME TREE. THE ENDANGERED SERIANTHES NELSONII TREE MAKES A LEAF THAT USES THIS SAME DESIGN.... view more 

CREDIT: UNIVERSITY OF GUAM

Newly published research carried out at the University of Guam has used a critically endangered species to show how trees modify leaf function to best exploit prevailing light conditions. The findings revealed numerous leaf traits that change depending on the light levels during leaf construction.

"The list of ways a leaf can modify its shape and structure is lengthy, and past research has not adequately looked at that entire list," said Benjamin Deloso, lead author of the study.

The results appear in the October issue of the journal Biology (doi:10.3390/biology9100333).

Terrestrial plants are unable to move after they find their permanent home, so they employ methods to maximize their growth potential under prevailing conditions by modifying their structure and behavior. The environmental factor that has been most studied in this line of botany research is the availability of light, as many trees begin their life in deep shade but eventually grow tall to position their leaves in full sun when they are old. These changes in prevailing light require the tree to modify the manner in which their leaves are constructed to capitalize on the light that is available at the time of leaf construction.

"One size does not fit all," Deloso said. "A leaf designed to perform in deep shade would try to use every bit of the limited light energy, but a leaf grown under full sun needs to refrain from being damaged by excessive energy."

The research team used Guam's critically endangered Serianthes nelsonii tree as the model species because of the complexity of its leaf design. This tree's leaf is classified as a bi-pinnate compound leaf, a designation that means a single leaf is comprised of many smaller leaflets that are arranged on linear structures that have a stem-like appearance. The primary outcome of the work was to show that this type of leaf modifies many whole-leaf traits in response to prevailing light conditions. Most literature on this subject has not completely considered many of these whole-leaf traits, and may have under-estimated the diversity of skills that compound leaves can benefit from while achieving the greatest growth potential.

This study provides an example of how plant species that are federally listed as endangered can be exploited for non-destructive research, helping to highlight the value of conserving the world's threatened biodiversity while demonstrating a universal concept.

The study was a continuation of several years of research at the University of Guam designed to understand the ecology of the species. The research program has identified recruitment as the greatest limitation of species survival. Recruitment is what botanists use to describe the transition of seedlings into larger juvenile plants that are better able to remain viable. Considerable seed germination and seedling establishment occur in Guam's habitat, but 100% of the seedlings die. Extreme shade is one of the possible stress factors that generate the seedling mortality. Testing this possibility by providing outplanted seedlings with a greater range of sunlight transmission than the 6% recorded in this study may provide answers to the extreme shade stress hypothesis.

The latest results have augmented the team's earlier research that demonstrated how a specialized leaf gland enables rapid leaflet movement when the light energy is excessive. This skill of being able to change the leaflet's orientation is an instantaneous behavior that mitigates the damage that may result from excessive sunlight exposure.

"Just because the tree can't move itself, that doesn't mean it can't move its leaves to avoid stress," Deloso said.

Serianthes nelsonii was listed on the Endangered Species Act in 1987. A formal plan to recover the species was published in 1994 and called for research to more fully understand the factors that limit success of the species. This latest publication adds to the expanding knowledge that the University of Guam is generating to inform conservation decisions into the future.

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Further Reading:

Deloso, B.E. and T.E. Marler. 2020. Bi-pinnate compound Serianthes nelsonii leaf-level plasticity magnifies leaflet-level plasticity. Biology 9: 333; doi:10.3390/biology9100333.