High temps due to global warming will be dramatic even for tardigrades

Global warming, a major aspect of climate change, is already causing a wide range of negative impacts on many habitats of our planet. It is thus of the utmost importance to understand how rising temperatures may affect animal health and welfare. A research group from Department of Biology, University of Copenhagen has just shown that tardigrades are very vulnerable to long-term high temperature exposures. Animals, which in their desiccated state are best known for their extraordinary tolerance to extreme environments.

In a study published recently in Scientific Reports, Ricardo Neves and Nadja Møbjerg and colleagues at Department of Biology, University of Copenhagen present results on the tolerance to high temperatures of a tardigrade species.

Tardigrades, commonly known as water bears or moss piglets, are microscopic invertebrates distributed worldwide in marine, freshwater and terrestrial microhabitats.

Ricardo Neves, Nadja Møbjerg and colleagues investigated the tolerance to high temperatures of Ramazzottius varieornatus, a tardigrade frequently found in transient freshwater habitats.

- "The specimens used in this study were obtained from roof gutters of a house located in Nivå, Denmark. We evaluated the effect of exposures to high temperature in active and desiccated tardigrades, and we also investigated the effect of a brief acclimation period on active animals," explains postdoc Ricardo Neves.

Rather surprisingly the researchers estimated that for non-acclimated active tardigrades the median lethal temperature is 37.1°C, though a short acclimation periods leads to a small but significant increase of the median lethal temperature to 37.6°C. Interestingly, this temperature is not far from the currently measured maximum temperature in Denmark, i.e. 36.4°C. As for the desiccated specimens, the authors observed that the estimated 50% mortality temperature is 82.7°C following 1 hour exposures, though a significant decrease to 63.1°C following 24 hour exposures was registered.

The research group used logistic models to estimate the median lethal temperature (at which 50% mortality is achieved) both for active and desiccated tardigrades.

Approximately 1300 tardigrade species have been described so far. The body of these minute animals is barrel-shaped (or dorsoventrally compressed) and divided into a head and a trunk with four pairs of legs. Their body length varies between 50 micrometers and 1.2 millimeters. Apart from their impressive ability to tolerate extreme environments, tardigrades are also very interesting because of their close evolutionary relationship with arthropods (e.g., insects, crustaceans, spiders).

As aquatic animals, tardigrades need to be surrounded in a film of water to be in their active state (i.e., feeding and reproducing). However, these critters are able to endure periods of desiccation (anhydrobiosis) by entering cryptobiosis, i.e., a reversible ametabolic state common especially among limno-terrestrial species. Succinctly, tardigrades enter the so-called "tun" state by contracting their anterior-posterior body axis, retracting their legs and rearranging the internal organs. This provides them with the capacity to tolerate severe environmental conditions including oxygen depletion (anoxybiosis), high toxicant concentrations (chemobiosis), high solute concentration (osmobiosis) and extremely low temperatures (cryobiosis).

The extraordinary tolerance of tardigrades to extreme environments includes also high temperature endurance. Some tardigrade species were reported to tolerate temperatures as high as 151°C. However, the exposure time was only of 30 minutes. Other studies on thermotolerance of desiccated (anhydrobiotic) tardigrades revealed that exposures higher than 80°C for 1 hour resulted in high mortality, with almost all specimens dying at temperatures above 103°C. It remained, yet, unknown how anhydrobiotic tardigrades handle exposures to high temperatures for long periods, i.e., exceeding 1 hour.

- "From this study, we can conclude that active tardigrades are vulnerable to high temperatures, though it seems that these critters would be able to acclimatize to increasing temperatures in their natural habitat. Desiccated tardigrades are much more resilient and can endure temperatures much higher than those endured by active tardigrades. However, exposure-time is clearly a limiting factor that constrains their tolerance to high temperatures.," says Ricardo Neves.

Indeed, although tardigrades are able to tolerate a diverse set of severe environmental conditions, their endurance to high temperatures is noticeably limited and this might actually be the Achilles heel of these otherwise super-resistant animals.


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Materials provided by Faculty of Science - University of Copenhagen. Note: Content may be edited for style and length.

Unprecedented Crisis: Australia and its Raging Forest Fires

The local officials from Australia urged a massive exodus from some cities from the south coast of the country where there are 200 fires which are destroying the New South Wales and Victoria in a revived fire due to the high temperatures and strong winds.

The extreme heat, which was expected for the weekend, will increase even much more the fire in the coastal communities that are already facing the electric and communication cuts, food and running water shortages, as well as fuel shortage after having been isolated.

Long queues were created in the outside areas of supermarkets and gas stations while the local citizens and tourists were looking for related supplied to be sheltered or escaping from the fires.

Ships and helicopters already began to rescue thousands of people trapped by the fires as part of the biggest evacuation of local citizens ever carried out in that region.

Helping the residents and visitors trapped in Mallacoota small town is among the planned related operations as it is a small and popular holiday place that attracts thousands of visitors each Summer in which they looked for safety in its beaches while fleeing from the intense fires last Tuesday.

   Unprecedented Crisis: Australia and its Raging Forest Fires

The Naval authorities have a proper ship to transport up to one thousand people in a first journey as part of an maneuver that will require two or three journeys in the upcoming days, taking into account the nearer port to Mallacoa town is 16 hours distant.

The chief of the Australian Royal Navy, Michael Noonan, regretted to have to prioritize who is evacuated from Mallorca and who will have to remain in the little town where the possible transit of vehicles to that place was blocked by the fall of some trees on the roads.

Thousands of people had already been rescued from the adjacent East Gippsland region that is one of the biggest rescue operations of that kind since the northern Darwin city evacuated more than 35000 people after the Tracy hurricane in 1974.

Since October, the forest fires has affected the south-east region of Australia where more than five million hectares has been destroyed nationwide and over 1400 houses were destroyed.

The death Toll is 16 and its capital city that is Camberra has become one of the most polluted of the world as it faces the smoke high levels caused by the fire in the forest.

   Unprecedented Crisis: Australia and its Raging Forest Fires

The Australian Prime Minister, Scott Morrison, reiterated to the local journalists that the priority is fighting the fires and evacuating the population to a safe place, A team made up of a hundred experts and firefighters from the United States and Canada help the Australians to face that serious crisis.

It is expected a difficult day due to fires, strong winds and temperatures higher to 40 Centigrade Degrees. Those conditions will increase the fire.

It could be even worse than last Tuesday that was the deadliest day since the beginning of the forest fires season in Australia.

The unprecedented crisis has caused demonstrations by the Australians who are requesting immediate measures against the global warming that responsible for those fires lasting much more and more intense than ever, according to the scientists.

  • Published in World

Climate Change Corrodes Shark Skin

We’ve heard it before that sharks have repeatedly survived mass extinctions… surely, they should be able to survive the one our planet seems to currently be undergoing, right? Although they have been around since the dinosaurs, it seems sharks are facing their most fearsome foe yet: climate change.

After destroying their habitats, overfishing, and hunting them, humans have caused shark numbers to decline at a staggering rate. In a study published in the journal https://www.nature.com/articles/s41598-019-54795-7">Scientific Reports, researchers show that prolonged exposure to acidified water corrodes shark’s skin. Shark skin is not like ours; it’s made up of thousands of little scales, called dermal denticles, that have a makeup like teeth. While some can be seen by the naked eye, the impact acidic water has on dermal denticles can only be seen via electron microscope. But how acidic are we talking about? Currently our oceans average a pH of 8.1, which is apparently 25 percent more acidic than in pre-industrial times. For this research, the scientists kept puffadder shysharks (Haploblepharus edwardsii) in tanks of 7.3 pH water. Why this specific number? According to one estimate, ocean water could be this acidic by the year 2300.

“It's probably not going to be an average for the ocean, even in 2300,” Luiz Rocha, curator of fishes at the California Academy of Sciences, told Wired. “Unless instead of slowing down, we continue racking up the amount of greenhouse gases that we're dumping in the atmosphere. If it drops to 7.3, we are doomed. Everything is going to fall apart, not just sharks.”

Climate change will have an enormously varied impact on the world’s oceans. Overall, some changes that can be expected include increased warming, a decrease in pH levels, decreases in dissolved oxygen (leading to more ‘dead spots’ of very low oxygen), and changes in salinity. For highly mobile animals such as sharks, it’s harder to study how these changes will impact them. Already we are seeing shifts in their swimming behavior and changes to migratory patterns, food availability and altered brain development are all predicted to occur if things continue the way they are.

Scanning electron micrographs show that the denticles of puffadder shysharks kept in pH 7.3 water for nine weeks (right) were substantially more degraded than those of sharks kept in normal ocean water (left).

Scanning electron micrographs show that the denticles of puffadder shysharks kept in pH 7.3 water ... [+]

J. DZIERGWA ET AL/SCIENTIFIC REPORTS 2019

But not all sharks are migratory. Some, like this slender benthic catshark, stay in one spot. Puffadder shysharks are endemic to the coast of South Africa, preferring the cold waters here to scavenge on crustaceans, polychaetes and small fishes. Camouflaged due to their sandy color and reddish saddles with dark and white spots, they tend to be seen as pests by local fishermen due to them eating bait off their hooks. While seen as a nuisance to some, they were a great study species since they have such a restricted range! The experiments, done in a lab, were carried out for nine weeks where after the researchers looked at the puffadder’s dermal denticles. On average, a quarter of the denticles on the sharks in acidic water were damaged, compared to 9.2 percent on the controls. “Damaged denticles may impact their ability to hunt or escape,” study co-author Lutz Auerswald, biologist at Stellenbosch University in South Africa, told Wired. “In addition, since sharks’ teeth are from the same material, corrosion may impact hunting and feeding.”

Ocean acidification is a major, but often less understood, concern for sharks. In fact, all sharks and their relatives (rays, skates, and chimaeras) have teeth and denticles made from this same material that seems to be vulnerable in increasingly acidic water. While done in a lab and only on one species, the results are still troubling. Our oceans may not get this acidic in the near future, but it’s just another hurdle for these animals to overcome. Currently they face more pressing threats such as overfishing and bycatch, habitat destruction, and even shark finning. But climate change shouldn’t be ignored. “The rate of climate change is very fast compared to previous changes,” says Auerswald. “Most likely, shark species will feel the impact differently and some may not be able to cope, whereas others may have the potential to adapt.”

Cubans promote program to face climate change

Different tasks have been carried out during the current year in the central province of Sancti Spiritus, aimed at reducing the negative impacts of climate change.

As part of the so-called Tarea Vida, studies on water salinity in coastal areas were undertaken in 2019 and to determine the progress of erosion on Ancon beach, located in the central southern city of Trinidad, a World Heritage Site.

Likewise, the improvement of soils and the reforestation of coastlines were undertaken in the present year in the province as part of the program, described as a State Plan for confronting climate change.

According to information released here Monday, vital importance is attached to the prioritized areas of the municipalities of La Sierpe and Sancti Spiritus, dedicated to the cultivation of rice, affected by drought and saltwater intrusion.

The aforementioned State Plan is grounded on a scientific base that prioritizes 73 of the 168 Cuban municipalities, 63 of them in coastal areas and another ten within the territory.

It includes five strategic actions and 11 tasks aimed at counteracting impacts in vulnerable areas. It is inspired by the thought of the historic leader of the Cuban Revolution Fidel Castro (1926-2016), expressed at the Earth Summit in 1992, where he described the challenges facing humanity due to climate change.

  • Published in Cuba

Coral reefs with higher microbial diversity are much healthier, study finds

A collaborative study that compared seawater from 25 reefs in Cuba and the U.S. Florida Keys, which varied in human impact and protection, found that those with higher microbial diversity and lower concentrations of nutrients and organic carbon (primarily caused by human activities) were markedly healthier.

Researchers sampled seawater from each site and measured nutrients as well as a variety of other parameters that offer insight into the microbial community. They found a notable difference between the heavily protected offshore reefs in Cuba and the more impacted nearshore ones in the Florida Keys.

They found that exploring the connection between microorganisms and the health of coral reefs can be difficult due to the lack of unspoiled reef systems around the world.

“Human impacts such as overfishing and pollution lead to changes in reef structure,” says WHOI graduate student Laura Weber, lead author of the paper. “Removal of algae grazers such as herbivorous fish and sea urchins leads to increases in macroalgae, which then leads to increased organic carbon, contributing to the degradation of coral reefs.”

The study outlines how offshore and highly-protected reefs are healthier than nearshore reefs with less protection from human impacts. Additionally, reefs with lower nutrient runoff and carbon from industrial activities are markedly healthier.

“Cuba does not have large-scale industrialised agriculture or extensive development along most of its coastline,” says Patricia González-Díaz, Director of CIM-UH and co-author of the study. “So there is not a lot of nutrient run-off and sedimentation flowing on to the reefs.”

Additionally, the reefs of Jardines de la Reina, the largest protected area in the Caribbean, may be further buffered from impacts by the mangroves and seagrass meadows that lie between the island of Cuba and the reef system of Jardines de la Reina. Here, researchers found low concentrations of nutrients, and a high abundance of Prochlorococcus—a photosynthetic bacterium that thrives in low nutrient waters. More accessible and heavily-impacted areas in Florida Keys both contained higher organic carbon and nitrogen concentrations.

The work suggests that protection from a variety of human impacts does play a significant role in maintaining microbial diversity. The hope is that these findings could aid resource managers in deciding how best to protect and restore Caribbean coral reefs in the face of habitat and climate-based change.

To read the full paper, Microbial signatures of protected and impacted Northern Caribbean reefs: changes from Cuba to the Florida Keys,click here. Co-authors of the paper include colleagues from CIM-UH, Universidad Nacional Autónoma de México, Phillip and Patricia Frost Museum of Science, Mote Marine Laboratory, and the University of California, Santa Barbara.

Photograph by Amy Apprill, courtesy of Woods Hole Oceanographic Institution.

Global warming trend will continue in 2020

London, Dec 20 (Prensa Latina) The trend of rising temperatures will continue next year with an average of 1.11 degrees Celsius in relation to pre-industrial levels, according to data reported by Met Office, a UK meteorological service.

2020 will be added to the series of the hottest years in history for six consecutive years and its main cause is the increase in greenhouse gas emissions, explains the entity in its report.

In addition, the text remembers that the warmest year so far was 2016, when a strong El Niño phenomenon made a significant difference.

This meteorological phenomenon causes sea surface temperatures to increase in the central and eastern Pacific and is associated with a series of impacts worldwide, including the overall level of global warming, it explains.

However, the chances of a strong El Niño in 2020 are low, the source specifies.

It details that the global average temperature next year will be in the range of 0.99 to 1.23 degrees Celsius with a central estimate of 1.11.

  • Published in World

Failure of UN climate summit continues to haunt the world

Madrid, December 17 (RHC)-- The failure of the United Nations climate summit continues to haunt the international community.  Negotiators could not agree on a deal that would limit global warming to 1.5 degrees Celsius, or 2.7 degrees Fahrenheit, above pre-industrial levels — a key goal of the Paris Agreement. 

Scores of civil society groups condemned governments in the European Union, Australia, Canada and the U.S. for blocking progress at the talks.  Alden Meyer, strategy chief at the Union of Concerned Scientists, said: “Never have I seen the almost total disconnect we’ve seen here at COP25 in Madrid between what the science requires and what the climate negotiations are delivering in terms of meaningful action.” 

Ian Fry, the climate negotiator for the Pacific island nation of Tuvalu — whose existence is threatened by rising sea levels — called out the United States for watering down the final document even though Donald Trump is withdrawing from the Paris Agreement.  Ian Fry said: “This is an absolute tragedy and a travesty on those affected by the impacts of climate change.  There are millions of people all around the world who are already suffering from the impacts of climate change.  Denying this fact could be interpreted by some to be a crime against humanity.”

Environmentalists and indigenous leaders blasted the United Nations for marginalizing civil society groups over two weeks of negotiations, while welcoming polluters at the climate summit. 

Kera Sherwood-O’Regan, a Maori representative from the Indigenous Peoples Organizations at the COP, told reporters: “When you silence us, you deny yourselves learning from our ways, and you continue to sideline those who have real solutions for all communities.  We are experts on climate.  We are the kaitiaki, the stewards of nature.  We know the legitimacy of our voices, and it’s about time that you recognized it, too.  Hear our stories.  Learn our histories.  Stop taking up space with your false solutions and get out of our way.”

Edited by Ed Newman
  • Published in World

Climate change: Five things we've learned from Madrid talks

At the conclusion of UN climate talks in Madrid, our environment correspondent Matt McGrath considers the key lessons.

1. Leadership is REALLY important

COP25 in Madrid only happened because the Chilean government, faced with mounting civil disorder, decided to cancel the meeting in Santiago.

Spain stepped in and in three weeks organised a well-resourced and well-run event.

However, the fact that it was being run by one government, while hosted by another, gave rise to severe difficulties.

Delegates were highly critical of the fact that when it came to the key text about ambition, the Chileans presented the lowest common denominator language first, resulting in a huge number of objections from countries eager to see more ambition on carbon cuts.

Experienced COP watchers said they should have started with high ambition and negotiated down to a compromise.

Insiders say that agreement was only found because of the influence of Spanish minister Teresa Ribera who played a key role in bringing parties together during the long, last night of negotiations.

2. Disconnect is the key word

This was the word that was most widely used to describe COP25.

There was a yawning gap between the demands of those outside the process and the actions of those within.

This disconnect was the difference between the urgency underlined by the latest science, the demands for more ambitious climate targets from school strikers around the world, and the torturous, convoluted nature of the talks.

During the talks, young activists staged an unauthorised protest that saw hundreds ejected by security.

"It's clear that civil society is at a boiling point, they are frustrated with the glacial pace and they are livid with the presence of polluters and their trade associations," said Sriram Madhusoodanan from Corporate Accountability, a campaign group that monitors the presence of the oil and gas industry at COP.

"If these talks are ever going to deliver, governments have to take a long serious look at why its failed for 25 years, and start by kicking polluters out."

3. Leipzig in September

This will be the most critical climate encounter in 2020.

The next conference of the parties may be in Glasgow, but the chance of any real success there will be determined, to a large extent by what happens in the EU-China summit taking place in the German city of Leipzig next September.

The hope is that by then the EU will have formalised its zero-carbon long term goal and also updated its 2030 pledge to cut emissions by 55% of 1990 levels.

The EU will likely try and secure agreement from the Chinese to improve their nationally determined contribution (NDC).

Back in 2014 the climate pact signed by President Obama and President Xi Jinping became the lynchpin of the Paris Agreement.

Many observers hope that if the EU and China can do the same, it will be a massive boost for Glasgow.

"The good news is that the Chinese president is coming to the summit," said Li Shuo, a senior policy adviser with Greenpeace China.

"From the Chinese perspective the NDC enhancement decision is one that has to be made at the very top level so the fact the president is going would provide one potential condition for a political level decision."

4. The elephant in the room….

At Paris in 2015, countries submitted their first climate plans, which was relatively easy for many of the larger developing countries.

But in 2020, they are supposed to do much more and as Madrid proved, many are fighting this hard.

The actions of the US in pulling out of Paris and adopting an antagonistic attitude to the COP have chimed with the desire among some of the larger emitters to put off difficult decisions.

That was clearly evident in Madrid.

So Australia fought hard to keep old carbon credits in the system because it wants to use them to reduce its own carbon rather than taking actions that might impact consumers.

India became much more vocal about the need for an examination of whether richer countries have done enough in the years running up to 2020.

If countries can't be persuaded to move away from these self-protective positions, Glasgow will suffer the same fate as the ill-fated Copenhagen COP in 2009.

5. Glasgow has a mountain to climb

The key takeaway from Madrid is that making progress in climate talks requires huge preparation, strong diplomacy and very committed leadership.

Because Madrid failed to clarify so many key issues the onus now falls on the UK to resolve many of the most challenging questions.

In Glasgow, the question of loss and damage, of carbon markets, transparency and many other technical issues will need to solved.

Most importantly the countries will have to agree a major boost in their carbon cutting if the world is to keep the rise in global temperatures under 1.5C this century.

At a time when the UK will be negotiating trade deals with the EU and with the US, it is going to require enormous diplomatic clout to deal with the climate question as well.

"The diplomacy to build the confidence of the Chinas and the Indias that they can do more and they will be supported, through economic co-operation and that everyone else is moving in that direction, is incredibly important for changing the politics heading into next year," said Jennifer Tollman, a climate expert with the E3G think tank.

"The UK can't do it on its own. They will have to outsource this to people they know and trust."

There was a yawning gap between the demands of those outside the process and the actions of those within.

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