Alaska grizzly bears on webcams


This video is called Battle Of The Giant Alaskan Grizzlies.

From eNature.com in the USA:

Watch Live As Grizzlies Catch Salmon

Salmon are running in Alaska and Brooks Falls in Katmai National Park may be the best place to watch local bears gorge themselves on fresh caught salmon.

Explore.org has a number of webcams on the scene and you can almost always observe a bear or two (or three or four!) in action.

Bahamas, built by bacteria from Saharan dust?


This video says about itself:

Wildlife of Exuma Island, Bahamas – Lonely Planet travel video

Visitors to sparsely populated Exuma, a remote island in the Bahamas, can expect a close encounter with sharks and iguanas.

From New Scientist:

Bahamian paradise built by bacteria using Saharan dust

13:40 28 July 2014 by Flora Graham

The Bahamas may have been created by bacteria thriving on minerals in dust from the Sahara desert, 8000 kilometres away.

In this NASA satellite image from 2009, it is possible to see how the many islands of the Bahamas are actually the highest points of distinct areas where the sea is shallow and turquoise.

These turquoise waters mark the top of the Bahama Banks – underwater columns of coral reef limestone more than 4500 metres tall that have formed over the past 100 million years. It was thought that tiny plants and animals generate the vast amounts of carbonate that make up the towers, similar to how coral reefs are formed. But the surrounding sea is poor in nutrients, so what would have sustained them is a mystery.

Now researchers including Peter Swart from the University of Miami’s Rosenstiel School of Marine and Atmospheric Science in Florida are showing that photosynthetic cyanobacteria may actually have done much of the construction.

Cyanobacteria are involved in the precipitation of calcium carbonate in the sea, but they would have needed an enormous amount of iron to do their work. This could have been provided by the dust that blows across the Atlantic from the Sahara.

There are characteristic traces of iron and manganese in recent carbonate sediment on the banks, pointing to their Saharan origin. So the team suggests that the Bahama Banks are being built up by cyanobacteria and may also have been in the past.

The results of this research are here.

Seahorse sounds, new study


This video is called The World of Seahorses.

From the Journal of ZooLogy:

Sounds produced by the longsnout seahorse: a study of their structure and functions

Abstract

Seahorses are known to produce sounds in different behavioural contexts, but information on the sound production in this fish group is scarce. Here we examined the acoustic behaviour of the longsnout seahorse Hippocampus reidi by analysing sound production when fish were introduced to a new environment and during feeding, handling and courtship. We show that males and females produce two distinct sound types: ‘clicks’ (main energy between 50 and 800 Hz) during feeding and courtship, and previously undescribed ‘growls’ (main energy concentrated below 200 Hz).

The latter consists of series of sound pulses uttered in stress situations when the animals were handheld. Growls were accompanied by body vibrations, and may constitute an additional escape mechanism in seahorses, which might startle predators. During reproductive behaviour, clicks were most abundant on the third (last) day of courtship; they were particularly associated with the males’ pouch-pumping behaviour, suggesting synchronization between sound production and courtship behaviour. This is consistent with the biology of Hippocampus species, which are mostly monogamous and form pair bonds. Thus, a courtship call may be used to signal readiness to mate.

Hammerhead sharks in danger


This video is called Shark Academy: Scalloped Hammerhead Sharks.

From Wildlife Extra:

US lists four species of hammerhead shark under its Endangered Species Act

The US National Marine Fisheries Service has recently listed four populations of scalloped hammerhead shark, Sphyrna lewini, under the American Endangered Species Act (ESA), because of severe threats posed by human exploitation.

“It’s sobering that we must begin adding shark species to the endangered species list,” said Taylor Jones, endangered species advocate for WildEarth Guardians, an American non-profit organisation.

“Our oceans are in serious trouble and this is only the first step toward protecting and restoring the ocean ecosystems that these amazing carnivores call home.”

Shark species worldwide are dwindling in the face of heavy fishing pressures, with animals killed for their meat and fins.

Sharks are also accidentally caught and killed in the course of fishing operations targeting other species. In fact, experts consider fishing to be the greatest threat to the future of all shark species.

Most sharks, including the scalloped hammerhead, maintain oceanic ecosystems as apex carnivores. Ecosystem stability and biodiversity, the preservation of which is the main goal of the ESA, can suffer from the removal of this top predator.

Scalloped hammerheads can be grouped into six distinct populations distinguished by genetics, geography, and behaviour. The new listing rule protects the Central and Southwest Atlantic populations and the Indo-West Pacific populations as Threatened, and the Eastern Atlantic and Eastern Pacific populations as Endangered.

“The listing of the scalloped hammerhead is an important indication that the human exploitation of marine species has taken its toll,” said Michael Harris, Director of the Wildlife Law Program that was launched last year by the American organisation, Friends of Animals, to use environmental laws to protect wildlife and their habitats.

“In fact, nearly half of all marine species worldwide face the threat of extinction as a result of anthropogenic action, including destructive fishing methods, pollution, climate change and ocean acidification.

“It is about time that our government took action to protect hammerheads. Now they should do the same for the many species still awaiting review under the ESA.”

Listing under the ESA has proven to be an effective safety net for imperiled species. Proponents say the law is especially important as a bulwark against the current extinction crisis.

Due to human activities, plants and animals are disappearing at a rate much higher than the natural rate of extinction. Scientists estimate that 227 species would have become extinct if they had not been listed under the ESA.

Listing species with a global distribution can protect the species in the United States and help focus resources toward enforcement of international regulation and recovery of the species.

Tens of millions of sharks are killed every year — mostly for the sake of a bowl of soup — but conservationists hope that that the multibillion-dollar trade in shark fins will soon be more endangered than the sharks. Several trends are coming together — including high-profile pledges in China to swear off the traditional soup, to laws banning shark fins from menus, to new international export regulations that are due to take effect in September: here.

USA: Sharks in Cape Cod Town Draw Tourists, Flipping the ‘Jaws’ Script: here.

Escher art in Costa Rica


Metamorphosis III, 30 March 2014

Still 30 March 2014, in the botanical garden of Heredia in Costa Rica. Not just birds in that garden; art as well. This art, based on the woodcut print Metamorphosis III by Dutch artist M.C. Escher, was in one of the garden buildings; a round gazebo.

Escher, Metamorphosis III reptiles, 30 March 2014

In Escher’s work, reptile forms slowly morph into other forms.

Escher, Metamorphosis III more reptiles, 30 March 2014

Escher, Metamorphosis III bees, 30 March 2014

And bees morph into other insects.

Escher, Metamorphosis III birds, 30 March 2014

And birds into fish.

Escher, Metamorphosis III birds and mammals, 30 March 2014

And birds into mammals.

Escher, Metamorphosis III yet more reptiles, 30 March 2014

Until we were back at the reptiles again.

Reddish egrets, what do they eat?


This video from the USA is called Crazy Reddish Egret dance hunting for fish, Marco Island, Florida.

From Waterbirds in the USA:

Comparisons of Reddish Egret (Egretta rufescens) Diet During the Breeding Season Across its Geographic Range

Abstract

Although the prey of Reddish Egrets (Egretta rufescens) generally consists of shallow-water, euryhaline fish species, rangewide differences in breeding season diet have not been examined. Furthermore, the relative proportions of the two Reddish Egret color morphs vary from east to west across the species’ range. Color morph may influence foraging efficiency, but variations in prey across the species’ range and between morphs is undocumented.

By examining boluses from Reddish Egret (n = 109) nestlings, prey species proportions were compared between morphs, among regions and among colonies within Texas. Between regions, prey species and proportion of species differed widely; however, fish species with similar life histories were selected across the Reddish Egret’s range (Bahamas: 100% sheepshead minnow (Cyprinodon variegatus); Texas: 85% sheepshead minnow; Baja California Sur: 49% American shadow goby (Quietula y-cauda); Yucatán: 64% Yucatán pupfish (C. artifrons).

Within the Laguna Madre in Texas, significant differences in prey species were not detected between morphs (F(1,61) = 1.36, P = 0.224); however, prey mass by species differed between colonies (F(1,60) = 2.68, P = 0.010). While our results only pertain to Reddish Egret diet during the breeding season, this study increases our understanding of Reddish Egret ecology and provides initial diet information across the species’ range.

Zander, underwater video


This is a video about a zander in the Haarlemermeersebos pond in Hoofddorp in the Netherlands.

Tveenstra made the video.

Prehistoric meteor shower and evolution of life discovery


This video is called Late Ordovician Mass Extinction (Ordovician – Silurian).

From daily The Independent in Britain:

Scientists discover fragment of ‘missing link’ asteroid that led to explosion of life on Earth

James Vincent

Thursday 03 July 2014

Scientists in Sweden have discovered a never-before seen class of meteorite that could be the ‘missing link’ between a gigantic collision in the asteroid belt 470 million years ago and the subsequent explosion of diverse life forms here on Earth.

Although it’s usually thought that meteorite impacts are disastrous for species on Earth (the classic example is the colossal impact thought to have killed off the dinosaurs 66 million years ago) there’s plenty of evidence to suggest that these events can also be beneficial to the overall diversity on the planet.

It’s thought that just such an impact – or rather, a string of them – dramatically boosted biodiversity on the planet during the Ordovician Period some 470 million years ago. It’s believed that a collision of two asteroids (or possibly an asteroid and a comet) out in space caused a shower of meteors to rain down on Earth.

Over time fragments of this meteor shower have been found around the planet and dated to 470 million years ago – but until now scientists had not found any evidence of the ‘killer’ asteroid that started this chain of events.

During the Ordovician Period most life on Earth was found in the ocean, with jawless fish, molluscs and insect-like arthropods making up the bulk of the species roll-call. However, a study from 2008 showed that the planet went through a “major phase of biodiversification” at this time shortly after “the largest documented asteroid breakup event during the past few billion years”.

The evidence for this breakup comes from the abundance of L-chondrite meteorites – the second most common meteorite type – fragments of which first started appearing on Earth around 470 million years ago.

“Something we didn’t really know about before was flying around and crashed into the L-chondrites,” said Gary Huss, co-author of the study that analysed the sample (published in Earth and Planetary Science Letters). This newly-discovered fragment is thought to be that very object – the mysterious ‘bullet’.

The composition of the fragment differs from known meteorite samples and its exposure age – the length of time it sailed through space – places it at the ‘scene of the crime’ when meteors rained down on the planet during the Ordovician Period.

“It’s a very, very strange and unusual find,” Birger Schmitz, the lead author of the study, told Live Science. “I think [it] adds to the understanding that the meteorites that come down on Earth today may not be entirely representative of what is out there.”

It’s not clear exactly why the Ordovician meteor shower led to a greater variety of life on the plane although some more far-fetched theories suggest that life itself was ‘seeded’ by organisms hitching a ride on asteroids.

A more likely explanation is that the impact craters caused by the collisions provided perfect test-beds for developing life. When meteorites hit the surface of the planet they scooped out bubbling pools of minerals and nutrients that served – in Carl Zimmer’s words – as “natural beakers that synthesized new chemicals essential for life”. However, even this is still just a theory – and the impacts might have also fostered life by creating new habitats, like restructured shorelines.

If further geochemical tests on the newly discovered fragment confirm its suspected origins then scientists will have pinned down another piece of the solar system’s history – but figuring out what happened closer to home might be more difficult still.

Parrotfish help coral reefs survice


This video says about itself:

The parrotfish is an interesting specimen. Not only do they change sex from female to male as they get older but parrotfish like blowing spit bubbles to sleep in.

A giant spit bubble sleeping bag.

In the morning the parrotfish goes about living its life on the reef, spending its day happily munching coral with its huge buck teeth. The fish grinds the coral down to extract the algae. Like all animals – what goes in must come out and the fish poops out the undigested rock as sand. A single fish can produce 200 lbs of sand a year.

From Wildlife Extra:

Corals need more parrotfish to survive

A decline in parrotfish and sea urchin numbers is a bigger cause of Caribbean coral loss than global warming, a new report suggests, and by increasing these populations the reefs have a chance of recovery.

The corals have declined by more than 50 per cent since the 1970s and only about one-sixth of their original coral cover remain.

These species are the area’s two main grazers and the loss of them breaks the delicate eco-balance of corals and allows algae, on which they feed, to smother the reefs.

“The rate at which the Caribbean corals have been declining is truly alarming,” says Carl Gustaf Lundin, Director of IUCN’s Global Marine and Polar Programme.

“But this study brings some very encouraging news: the fate of Caribbean corals is not beyond our control and there are some very concrete steps that we can take to help them recover.”

“Even if we could somehow make climate change disappear tomorrow, these reefs would continue their decline,” says Jeremy Jackson, lead author of the report and IUCN’s senior advisor on coral reefs.

“We must immediately address the grazing problem for the reefs to stand any chance of surviving future climate shifts.”

The research was carried out by the Global Coral Reef Monitoring Network (GCRMN), the International Union for Conservation of Nature (IUCN) and the United Nations Environment Programme (UNEP).