According to the study, published in the journal Proceedings of the Royal Society B, coral populations of the Mediterranean — essential for the functioning of the coral reefs, one of the most emblematic habitats in this sea — could be unable to recover from the recurrent impact of these extreme episodes, with water temperatures reaching high degrees for days and even weeks.

This is the first study to assess the long-term recovery capacity of populations of two emblematic species of Mediterranean coral: the red gorgonian (Paramuricea clavata) and the red coral (Corallium rubrum), which provide complex habitats that are essential for a great diversity of associated fauna. Therefore, it is essential to understand their resilience regarding the more frequent and intense heatwaves.

Mass mortality events

The climate crisis is severely affecting the marine ecosystems worldwide, and the Mediterranean is no exception. In particular, the marine heatwaves associated to the climate crisis are causing mass mortality events in all the coastal ecosystems of this basin, and among the most affected species are the Mediterranean corals.

Knowledge on the coral’s long-term resilience is still scarce, despite the studies that analysed the immediate impact of marine heatwaves on these organisms. These are long-lived species (more than a hundred years in some cases) and with slow populational dynamics (that is, organisms with low growth and recruitment rates), and therefore researchers need long temporary series (decades) to assess their recovery capacity.

As part of the study, the team analysed the results obtained in a long-term monitoring on different populations of coral affected by a great mass mortality caused by a heatwave in 2003 in the protected marine area of Scandola (Corsega, France). In particular, they analysed data on the state of these populations (density, size structure and biomass) collected during the following fifteen years to the heatwave, by the researchers of the MedRecover research group, formed by experts of the UB and ICM-CSIC, among other centres.

Far from recovery, the results show that all the analysed populations tended to collapse since they were affected by the 2003 heatwave. Fifteen years after this event, these populations are practically considered to be extinct from a functional perspective.

“We observed an average biomass loss regarding the initial biomass of 80% in populations of red gorgonian, and up to a 93% regarding the studied population of red coral,” notes Daniel Gómez, researcher at ICM-CSIC.

“These data are worrying for the conservation of these emblematic species, and it indicates that the effects of the climate crisis are speeding up with obvious consequences for the submarine landscapes, where the loss of coral equals the loss of trees in forests,” notes Joaquim Garrabou, also member of ICM-CSIC.

Recurrent exposure to heatwaves

Cristina Linares, professor at the Department of Evolutionary Biology, Ecology and Environmental Sciences of the Faculty of Biology and member of IRBio, says that “we believe one of the main reasons why we observed these collapse trajectories is the potential recurrent exposure to heatwaves, incompatible with the slow populational dynamics of these species.” In particular, during the study period (2003-2018), they registered important heatwaves in at least four years: 2009, 2016, 2017, 2018.

“During these heatwaves,” continues Linares, “the temperature conditions in the studied area reached extreme levels which are incompatible with the life of these corals, which probably caused new mortality events to the decimated populations and made the recovery impossible.”

Since we expect the number and intensity of marine heatwaves to increase over the following decades due to the climate crisis, the viability of many coral populations could be seriously threatened.

“However, there will probably be some areas in the Mediterranean in which, due to several factors, the recurrence of such climate impacts may be lower. This makes it especially relevant to keep — regarding other potential impacts — these climate refuges where the trajectories of coral populations could be more positive than those observed in this study,” notes the research team.

“Nevertheless, there is an urgent need for stronger measures to be implemented against the climate crisis before the loss of biodiversity becomes irreplaceable,” conclude the experts.

This study has been carried out thanks to the support of the Regional Natural Park of Corsica, the HEATMED National Plan project (RTI2018-095346-B-485 I00), the European projects H2020, MERCES, H2020 Futurmares, Interreg MED MPA-Engage and Interreg MED MPA-Adapt.

Now, she is a climate scientist and associate research professor of dendrochronology in the University of Arizona Laboratory of Tree-Ring Research. And she is trying to understand how a warming world is transforming the place she once called home.

Someday, the Arctic Ocean may no longer host ice, since the northern regions of the world are warming are faster than the rest — a trend scientists refer to as Arctic amplification. As Arctic ice melts, new opportunities and challenges for humans will arise, researchers say.

Freshwater flowing into the Arctic Ocean from the continent is thought to exacerbate Arctic amplification, but the extent of its impact isn’t fully understood. New research led by Panyushkina measures how the flow of the Yenisei River — the largest freshwater river that flows into the Arctic Ocean — has changed over the last few hundred years, and describes the impact freshwater has had on the Arctic.

Previous studies have attributed recent changes in wintertime freshwater flow into the Arctic to warming air temperature, seasonal precipitation changes or snowpack. But more recent research, including Panyushkina’s study, suggests that the primary driver is actually degradation of permafrost — or frozen ground — as well as forest fires across southern Siberia.

Panyushkina’s research, funded by the National Science Foundation Polar Office, is published in the journal Environmental Research Letters.

What trees can tell us

Data collected by instruments at the upper reaches of the Yenisei River in Tuva, in southern Siberia, only goes back so far. To overcome this, Panyushkina and her team used tree-ring data to double the number of years’ worth of the stream flow data they had, allowing them to look back 300 years.

Stream flow, or the amount of water that moves through a certain area of a river over time, can be inferred by measuring changing tree-ring thickness over the years. Measurements of stream flow over specific seasons can even be teased out of the data.

Annual stream flow information is commonly used by water managers to reveal the average changes in stream flow trends. But Panyushkina and her team did something novel when they decided to also investigate winter stream flow specifically.

“We found an unprecedented increase in the winter flow rate over the last 25 years,” Panyushkina said. This winter flow rate is nearly 80% above the average seen over approximately 100 years.

“In contrast, annual flow fluctuated normally during the 300-year period, with only a 7% increase over the last 25 years,” Panyushkina said.

The winter stream flow data revealed the role of permafrost melt on Arctic ice.

Since ice covers rivers during winter in Siberia, the team’s stream flow measurements only captured information about river waterthat originated underground rather thanfrom the sky. That includes water from thawing permafrost, as well as water from sub-permafrost aquifers, as permafrost loss leads to an increased exchange of water between the river and aquifers. These two sources of groundwater are warm compared to the frigid air above, and when they eventually flow into the Arctic Ocean, they melt the ice.

An uncertain future

Forest fires are also thought to be a driver of Arctic ice melt.

“We know the frequency and intensity of forest fires in Siberia have been increasing,” Panyushkina said. “When fires happen in forests with permafrost, there is deep thawing under the fire event, and the affected area often doesn’t recover for up to 60 years. When we have large-scale fires and long-burning fires and more frequent fires, we’re maybe hitting the critical point when permafrost degradation cannot return to normal. Forest fires are also another process that increases connectivity between aquifers and stream flow.”

The combined effects of permafrost degradation and fires are very strong at the Yenisei River basin, with more fresh water and heat flowing into the Arctic Ocean in recent decades, according to the study. In turn, melting sea ice also exacerbates global warming.

“Research interest in the region is booming because the surface temperature is warming much faster here than anywhere else in the world,” Panyushkina said. “It’s a hot spot for climate research, and because I grew up there and understand how the system works, it’s a natural topic of study for me. I’m also very interested in knowing the impact of an ice-free Arctic on the surrounding landscape. Humans have never seen an ice-free Arctic before, ever. My mind still cannot comprehend how the Arctic Ocean can be free of ice.”

By the middle of the century, changing sea ice conditions are expected to lead to greater navigability for open water-vessels crossing the Arctic. A future trans-Arctic shipping route called the Supra Polar Route will link the Atlantic and Pacific Oceans through the Arctic, potentially paving the way for more trans-Arctic commerce.

There is a need to quantify the Arctic amplification impacts to manage and regulate Arctic seas of the future, Panyushkina said.

“This strong prospect of the global trade fleet entering the Arctic opens the Pandora’s box of near-future geopolitical and environmental issues and reinforces the urgency for a new regulatory framework by international organizations to ensure adequate environmental protections and vessel safety standards,” she said.

To understand more about Arctic amplification and its consequences, Panyushkina and her team plan to study other rivers in Siberia.

“There are two more Siberian rivers similar in size to the Yenisei,” she said. “If we can quantify the stream flow from those rivers, we’ll have more precise and clear understanding of its impact on the Arctic.”

The study of the mineral and macronutrient composition of huhu grubs (Prionoplus reticularis larvae) was undertaken by Food Science PhD student Ruchita Rao Kavle and the results have recently been published in the International Journal of Food Science and Technology.

Miss Rao Kavle says the analysis found huhu grubs had a high fat content — for which they have traditionally been known — but it was the high levels of protein that really stood out.

“Across the four development stages of the huhu, protein ranged from 26.2 per cent to 30.5 per cent, which is high when compared to other common protein sources such as beef (21 per cent), lamb (20.3 per cent), chicken (17.4 per cent), soy (13 per cent), and chickpeas (20.5 per cent).

“We also found that the grubs were rich in essential minerals which all play vital roles in human health and nutrition, the most abundant been manganese, magnesium, phosphorus, iron, copper, and zinc,” she says.

The analysis was undertaken on wild huhu grubs during four different development stages of their life cycle, and which were harvested from a pine-forested site in Dunedin.

Miss Rao Kavle says based on the results, a person weighing 60kg would require around 170g of huhu, or about 75 huhu grubs, to meet the same daily protein requirement that could be sourced from 230g of beef.

“Compared to beef, a smaller amount of huhu needs to be consumed, but some people would find eating 75 grubs off-putting.”

Miss Rao Kavle’s research is also looking into options to process the grubs into more presentable forms such as flour and meals.

Study supervisor and co-author Dr Dominic Agyei says this pioneering study brings scientific evidence to highlight the nutritional value of the traditional food source.

He says that even though huhu grubs have not been accessible commercially in New Zealand, there is an ever-growing interest in sustainability in food production, alternative proteins, and the need to diversify food sources.

“A focus on indigenous foods, particularly their unique nutritional and health properties, and alternative proteins is surging. This study on the huhu comes on the back of other research we have also undertaken on the larvae of several edible insects such as mealworms and black soldier flies,” Dr Agyei says.

The research concluded that New Zealand wild-harvested huhu is nutritious and safe for consumption, however the authors point out that as with most foods, moderate consumption is recommended, and the importance of variety and balanced diets cannot be overruled.

Story Source:

Materials provided by University of Otago. Note: Content may be edited for style and length.

“Our results indicate that non-neutralising antibodies could also provide protection. This would mean that we have broader protection from antibodies than previously thought, making us less vulnerable to mutations of the virus. It warrants further investigation,” says Pontus Nordenfelt who led the study and is a researcher at Lund University.

In its efforts to produce vaccines and treatments, the research community has focused on neutralising antibodies, which prevent the spike protein of the virus from binding to the surface protein on our cells.

In a large project led by researchers at Lund University, a more detailed study has been carried out on how the immune system also fights off the virus by means of phagocytosis, the ability to ingest foreign particles, in Covid-19 patients.

Phagocytosis is a type of cleansing mechanism during which the immune system’s players target potential threats, such as bacteria or viruses, and ingests them, and this mechanism is facilitated if the harmful substance is marked by an antibody. The results, published in a themed issue of Frontiers in Immunology, indicate that non-neutralising antibodies are also important in the fight against Covid — through this mechanism.

“We observed that many of the antibodies that develop in response to Covid-19 are opsonising, i.e. they signal to the immune system’s phagocytes to ingest the virus. Our results indicate that non-neutralising antibodies, so long as they are able to opsonise, are also able to provide an effective response to the virus,” says Pontus Nordenfelt.

The findings are supported by experiments on mice, in which the non-neutralising antibodies protected the animals from Covid-19 infection.

The research team also discovered that the amount of neutralising antibodies affects the process of phagocytosis.

The team identified and isolated immune system cells from the blood of recovered Covid-19 patients. Using several techniques, they mapped which immune cells interact with the virus’s spike protein and identified the antibody binding sites. Then, using flow cytometry, they studied how these antibodies affect phagocytosis.

The researchers coated micrometre-sized beads with the spike protein and in doing so observed that the dosage of neutralising antibodies had an effect on the phagocytosis.

Opsonisation is the immune system mechanism in which an increase in bound antibodies triggers a stronger phagocyte response. Surprisingly, maximum opsonisation is already achieved at relatively low levels of antibodies. Beyond this, the researchers observed a reduction in the effect. The antibody-binding itself continued to increase linearly, even when the phagocytosis decreased, demonstrating that it is the spike protein that does something that causes this reduced phagocytosis.

To ensure that this was not due to other factors, the researchers set up the same experiment, but this time they used only monoclonal antibodies. This meant that just one type of antibody (clone) was used instead of the standard combination of thousands of different antibodies.

“It showed the same trend. Up to a certain level, there is a linear dosage effect from the antibodies. After that, it dips. Basically, when you give a dose that is too high you don’t get the protective effect,” says Wael Bahnan, researcher in infection medicine at Lund University and first author of the study.

“It looks like something is happening to the spike protein that results in reduced interaction with the white blood cells, leading to the immune system no longer binding to and neutralising the virus through phagocytosis. Similar phenomena have been described as the prozone effect and have been reported in experiments with pneumococcus and malaria. However, it has not been linked to reduced phagocytosis, so it is not certain that the effect relates to what we are observing in our experiments,” concludes Wael Bahnan.