Dutch students’ anti-climate change strike, 7 February


Dutch students' climate change protest organisers, Stijn Warmenhoven on the right, NOS photo

Translated from Dutch NOS TV today:

‘We should also do this’, after Belgium also climate march in the Netherlands

With the 35,000 Belgian pro-climate truants on today’s march as a big example, Dutch students also want to hold a climate march. The protest must take place on 7 February in The Hague.

The organization is in the hands of a group of students from the Dalton school in The Hague. Stijn Warmenhoven from 6 VWO is the spokesperson. “I saw on the news that thousands of young people were demonstrating in Belgium, and then I sent a message to a number of friends with: guys, we must do this, we also need to stand up for the climate in the Netherlands.”

… “We want to prepare ourselves as well as possible, so that the climate march will work just as well as in Belgium.”

The goal of the march is to move politics to action, says Warmenhoven. “You can not deny that there is climate change, and our generation is the last one who can do something about it, and we hope that politicians will listen and come up with changes that we can do something about.”

The student says he is disappointed in the recently presented climate agreement [of the Dutch government]. “Unfortunately, it is mainly the citizens who have to change, well, of course they have to change, but the big corporations that emit a lot of pollution have to change as well, and the climate agreement is not strict enough for them.”

3000 participants

The organizers hope for at least 3000 participants for the march. It is certain that there will be a start on the Malieveld. How the route then goes is discussed with the municipality of The Hague.

As in Belgium, the Dutch students want to protest different on Thursdays in a row. Even if they actually have to go to school on those days, one of the initiators says. “Truancy is actually against my principles, but if it is for a just cause, then truancy should be part of it at the moment.”

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Why Megalodon sharks were so big


This November 2017 video says about itself:

Sharks are cartilaginous fishes, what’s that? It means sharks don’t really have real bones. Size of sharks vary from species to species, from small shark size like Port Jackson sharks to medium size like whitetip reef and up to large size of the great white species and gigantic size of the basking shark species. Comparison of sharks are done against a grid and diver silhouette. Comparison and size of these shark species are taken from Wikipedia.

From Swansea University in Wales:

What it takes to be a giant shark

January 24, 2019

Summary: Have you ever wondered why the Megalodon shark became to be so big? Or wondered why some other sharks are much smaller?

In a paper published by Evolution, research led by Swansea University’s Dr Catalina Pimiento and co-authored by an international team of scientists from the UK, Europe and the USA examined the biological traits of all sharks and rays before running a series of evolutionary models to seek how gigantism evolved over time.

The results showed that for a shark to be giant, it would need to first evolve adaptations that enhance feeding such as the ability to control — at least to some degree — their own body temperature or become a filter feeder.

One of the most famous giant sharks, Megalodon — the topic of 2018 Hollywood film The Meg — was an active predator that could measure up to 18 metres in length and became extinct around two million years ago.

Meanwhile, the whale shark — which is still around today — can also reach 18 metres but isn’t an active predator. Instead, it is a filter feeder and eats tiny plankton from the sea.

These two subjects formed key parts of the research, which centred on the tree of life for sharks, where the authors mapped characteristics relating to body size, like their thermo-regulatory capacity, feeding mechanism and diet.

Researchers then found that sharks could become giants by following one of two possible evolutionary pathways; the mesothermic pathway, which consists of evolving the ability to self-control the temperature of their most important organs — or the filter-feeding pathway, which consists of evolving the ability to feed on microscopic plankton.

The mesothermic adaptation allows sharks to live in different types of habitats — including cold waters — and also hunt more effectively. The filter-feeding adaptation allows sharks to eat the most abundant food in the ocean — plankton.

However, there are risks involved for any shark following the evolutionary pathways that lead to gigantism. The mesothermic species need to consume big prey to maintain their high energetic demands, but when these prey are scarce, giant sharks are more susceptible to extinction. The scarcity of large prey in times of rapid climatic change was the most likely cause of the extinction of Megalodon.

While the filter feeders have shown more resilience, they are at risk of eating large volumes of toxic micro plastics that now can be found in the world’s oceans — thus threatening their extinction.

Dr Catalina Pimiento, lead researcher and Postdoctoral fellow at Swansea University, said:

“Sharks provide an ideal case study to understand the evolutionary pathways leading to gigantism in the oceans because they display contrasting lifestyles and adaptations, and because they have an evolutionary history of at least 250 million years.”

Coral species need other corals


This 2012 video says about itself:

Coral Gardening | South Pacific | BBC Earth

Conservationists work to garden coral and help preserve these unique life forms.

From the Georgia Institute of Technology in the USA:

When coral species vanish, their absence can imperil surviving corals

January 23, 2019

Summary: As coral species die off, they may be leaving a death spiral in their wake: Their absence could be sapping life from the corals that survive. In a new study, when isolated from other species, corals got weak, died off or grew in fragile structures. The study has shown it is possible to quantify positive effects of coral biodiversity and negative effects of its absence.

Waves of annihilation have beaten coral reefs down to a fraction of what they were 40 years ago, and what’s left may be facing creeping death: The effective extinction of many coral species may be weakening reef systems thus siphoning life out of the corals that remain.

In the shallows off Fiji’s Pacific shores, two marine researchers from the Georgia Institute of Technology for a new study assembled groups of corals that were all of the same species, i.e. groups without species diversity. When Cody Clements snorkeled down for the first time to check on them, his eyes instantly told him what his data would later reveal.

“One of the species had entire plots that got wiped out, and they were overgrown with algae,” Clements said. “Rows of corals had tissue that was brown — that was dead tissue. Other tissue had turned white and was in the process of dying.”

36 ghastly plots

Clements, a postdoctoral researcher and the study’s first author, also assembled groups of corals with a mixture of species, i.e. biodiverse groups, for comparison. In total, there were 36 single-species plots, or monocultures. Twelve additional plots contained polycultures that mixed three species.

By the end of the 16-month experiment, monocultures had faired obviously worse. And the study had shown via the measurably healthier growth in polycultures that science can begin to quantify biodiversity’s contribution to coral survival as well as the effects of biodiversity’s disappearance.

“This was a starter experiment to see if we would get an initial result, and we did,” said principal investigator Mary Hay, a Regents Professor and Harry and Linda Teasley Chair in Georgia Tech’s School of Biological Sciences. “So much reef death over the years has reduced coral species variety and made reefs more homogenous, but science still doesn’t understand enough about how coral biodiversity helps reefs survive. We want to know more.”

The results of the study appear in the February issue of the journal Nature Ecology and Evolution and were made available online on January 7, 2018. The research was funded by the National Science Foundation, by the National Institutes of Health’s Fogarty International Center, and by the Teasley Endowment.

The study’s insights could aid ecologists restocking crumbling reefs with corals — which are animals. Past replenishing efforts have often deployed patches of single species that have had trouble taking hold, and the researchers believe the study should encourage replanting using biodiverse patches.

40 years’ decimation

The decimation of corals Hay has witnessed in over four decades of undersea research underscores this study’s importance.

“It’s shocking how quickly the Caribbean reefs crashed. In the 1970s and early 1980s, reefs consisted of about 60 percent live coral cover,” Hay said. “Coral cover declined dramatically through the 1990s and has remained low. It’s now at about 10 percent throughout the Caribbean.”

“You used to find living diverse reefs with structurally complex coral stands the size of city blocks. Now, most Caribbean reefs look more like parking lots with a few sparse corals scattered around.”

84 percent loss

The fact that the decimation in the Pacific is less grim is bitter irony. About half of living coral cover disappeared there between the early 1980s and early 2000s with declines accelerating since.

“From 1992 to 2010, the Great Barrier Reef, which is arguably the best-managed reef system on Earth, lost 84 percent,” Clements said. “All of this doesn’t include the latest bleaching events reported so widely in the media, and they killed huge swaths of reef in the Pacific.”

The 2016 bleaching event also sacked reefs off of Fiji where the researchers ran their experiment. The coral deaths have been associated with extended periods of ocean heating, which have become much more common in recent decades.

10 times more species

Still, there’s hope. Pacific reefs support ten times as many coral species as Caribbean reefs, and Clements’ and Hay’s new study suggests that this higher biodiversity may help make these reefs more robust than the Caribbean reefs. There, many species have joined the endangered list, or are “functionally extinct,” still present but in traces too small to have ecological impact.

The Caribbean’s coral collapse may have been a warning shot on the dangers of species loss. Some coral species protect others from getting eaten or infected, for example.

“A handful of species may be critical for the survival of many others, and we don’t yet know well enough which are most critical. If key species disappear, the consequences could be enormous,” said Hay, who believes he may have already witnessed this in the Caribbean. “The decline of key species may drive the decline of others and potentially create a death spiral.”

864 abrasive animals

Off Fiji’s shores, Clements transported by kayak, one by one, 48 concrete tables he had built on land. He dove them into place and mounted on top of them 864 jaggy corals in planters he had fashioned from the tops of plastic soda bottles.

“I scratched a lot of skin off of my fingers screwing those corals onto the tables,” he said, laughing at the memory. “I drank enough saltwater through my snorkel doing it, too.”

Clements laid out 18 corals on each tabletop: Three groups of monocultures filled 36 tables (12 with species A, 12 with species B, 12 with species C). The remaining 12 tabletops held polycultures with balanced A-B-C mixtures. He collected data four months into the experiment and at 16 months.

The polycultures all looked great. Only one monoculture species, Acropora millepora, had nice growth at the 16-month mark, but that species is more susceptible to disease, bleaching, predators, and storms. It may have sprinted ahead in growth in the experiment, but long-term it would probably need the help of other species to cope with its own fragility.

“Corals and humans both may do well on their own in good times,” Hay said. “But when disaster strikes, friends may become essential.”

Corals lurking in deeper, darker waters could one day help to replenish shallow water reefs under threat from ocean warming and bleaching events, according to researchers: here.

Which Australian predators eat young birds?


This November 2018 video says about itself:

Last Pied Currawong chick makes the jump from the nest!

Each day for the last 4 days, one of the Currawong chicks made the jump from the nest. I was lucky enough to catch the last one. It’s a 10 metre drop, and it can’t fly yet, so no wonder it gets so worked up.

Pictures of this year’s nesting here.

From the University of Queensland in Australia:

It’s a bird-eat-bird world

January 24, 2019

Baby birds and eggs are on the menu for at least 94 species of animals in Australia’s forests and woodlands, according to new research from The University of Queensland.

PhD candidate Graham Fulton reviewed 177 existing bird studies across the country, identifying Australia’s most prolific nest predators and the factors affecting nest attacks.

“Predators attacking bird nests — known as nest predation — is the leading cause of nesting failure,” Mr Fulton said.

“Predators are always looking for their next meal and now we know who Australia’s common culprits are.

“In the reviewed research, 94 nest predators — from birds to reptiles to ants — were found to be attacking both natural and artificial nests.

“If you take out the artificial nests, it’s 69 species, and from that data there’s a clear dominant nest attacker in the Australia’s natural environment — the pied currawong.”

The pied currawong was found to be taking eggs and young from 29 different bird species; followed by the square-tailed kite (18 species), the tiger snake (15 species), the laughing kookaburra (10 species) and the grey shrike-thrush (eight species).

“These five nest predators were recorded as attacking a whopping 40 per cent of the prey measured by the number of prey species taken,” Mr Fulton said.

“The other 60 per cent of predation was carried out by the other 64 species, which included, by order of importance: birds, mammals, reptiles, frogs and ants.”

It also appears that the young and eggs of small ‘cup’ nesting birds, like the willie wagtail, are more often on the menu than other birds.

“This is probably because birds like willie wagtails are easily seen in the open, and they’re probably delicious and certainly nutritious,” Mr Fulton said.

“And predation at ‘cup’ and ‘dome’ nests was more frequently reported than at burrow, ground and hollow nests.

“When birds attack, they also prefer to eat the babies of other bird species whose parents are a quarter to a third of the predators’ weight.

“It’s a bird-eat-bird world out there, but at least we now know who’s doing the eating.”

An endangered Queensland bird is at risk of extinction because environmental legislation is failing to protect its habitat, according to a University of Queensland-led study. Researchers reviewed Australian and Queensland laws that protect threatened and endangered species, in light of a more than 80 per cent reduction in the distribution of the southern black-throated finch’s population. They found that despite the protection laws, extensive finch habitat loss has continued to be approved – with more in the pipeline: here.