Saturn’s moon Enceladus, new study


This video says about itself:

Warm Water Spots Found On Saturn’s Icy Moon Enceladus

12 March 2015

Astronomers have detected the first active hydrothermal vents outside of Earth’s seafloor on Saturn’s icy moon Enceladus, indicating conditions that could be hospitable to the initial development of life.

New research suggests the existence of warm spots on the ocean floor of Saturn’s icy moon Enceladus.

They could be the first active hydrothermal vents to be detected outside of Earth’s seafloor, and their conditions may even be similarly hospitable to the initial development of life.

Two studies, one led by the University of Colorado, Boulder and the other by the Southwest Research Institute in Texas, support the possible existence of this hydrothermal activity.

In 2005, the Cassini orbiter captured images of geysers shooting out of the moon’s surface, which led to the discovery of an underground sea believed to be approximately 6 miles deep and under about 25 miles of icy crust.

Scientists discovered particles from the geysers in one of Saturn’s rings and using an instrument onboard Cassini were able to analyze the tiny, uniform dust particles. They found they were rich in silica which is common on Earth but different from the usual ice crystals found in Saturn’s E-ring.

Because silica has such well-known properties, the only way they could create similar particles in the lab was using slightly alkaline, low-in-salinity water at temperatures of at least 194 degrees Fahrenheit.

Despite the ultra-cold environment, the moon’s high core temperature is thought to come from an effect called tidal heating where Saturn’s gravitational pull on the moon generates heat.

From the International Business Times:

On Saturn’s Moon Enceladus, Water Vapor Erupts In Giant Curtains: Study

By Avaneesh Pandey

May 08 2015 8:35 AM EDT

In 2005, NASA’s Cassini-Huygens spacecraft found evidence of an icy spray issuing from the southern polar region of Saturn’s sixth-largest moon, Enceladus. Now, just two months after scientists confirmed the presence of hydrothermal activity on the moon, researchers have claimed that the eruption of water vapor on its surface might be in the form of broad, curtain-like sheets, rather than discrete jets.

“We think most of the observed activity represents curtain eruptions from the ‘tiger stripe’ fractures, rather than intermittent geysers along them,” Joseph Spitale, a Cassini mission participating scientist and senior scientist at the Planetary Science Institute in Tucson, Arizona, said, in a statement, referring to prominent wavy fractures along the moon’s surface. “Some prominent jets likely are what they appear to be, but most of the activity seen in the images can be explained without discrete jets.”

According to a study published Thursday in the journal Nature, these “phantom jets” seen in simulated images produced by scientists line up perfectly with some of the features seen in real Cassini images. This means that the discrete geysers that scientists have observed on Enceladus are, in fact, an optical illusion created in places where these curtains fold against one another. This illusion is also responsible for creating regions of phantom brightness when viewers are looking through the folds of watery curtains.

“The viewing direction plays an important role in where the phantom jets appear,” Spitale said, in the statement. “If you rotate your perspective around Enceladus’ South Pole, such jets would seem to appear and disappear.”

On Earth, these curtain eruptions occur in regions of volcanic activity such as Hawaii, Iceland and the Galapagos Islands. However, unlike Enceladus’ watery curtains, these are curtains of fire.

Enceladus is believed to be covered with a layer of ice about 19 miles to 25 miles thick. Evidence strongly suggests that the moon harbors a six-mile-deep ocean, with temperatures reaching up to 194 degrees Fahrenheit below its thick, icy surface, making it a prime location to look for extraterrestrial life.

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.

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.

Galapagos islands, evolution and sea levels


This video says about itself:

How Have Sea-Levels Influenced Evolution on the Galapagos Islands?

This movie is a simple 0 m to -210 m geographical loop sequence at 5 m increments. Important features are the substantial gaps between Galapagos’ “core” islands even at -100 m. However, below c. -130 m the various islands begin coalescing.

Research: “Exploring the combined role of eustasy and oceanic island thermal subsidence in shaping biodiversity on the Galápagos” by Jason R. Ali and Jonathan C. Aitchison from the Journal of Biogeography.

From Wiley Research News:

The Galapagos Islands have an iconic status in the history of evolutionary study, now new research shows that the islands’ own geological past may have influenced the evolution of the chain’s native species.

Writing in the Journal of Biogeography, Jason Ali and Jonathan Aitchison explore how fluctuating sea level changes over thousands of years impacted the island chain’s ecology. They estimate that when the sea retreated, most recently 20,000 years ago, the water would have been 144m below its current level.

As a result, Santa Cruz, the island in the center of the archipelago, would have expanded, enveloping many of the smaller islands, while creating a series of shallow ‘land bridges’ between the volcanic outcroppings. Such bridges explain the range and diversity of the islands’ species, such as snakes, geckos and iguanas, which appear landlocked to modern eyes.

“As soon as I saw that that half the islands in the archipelago were sat on a single, shallow, submarine platform, I realized that the implications for biology could be significant,” said Dr. Ali. “My geological knowledge told me that sea-level falls must have regularly re-connected the islands, and that this must have profoundly shaped the landlocked biota’s distribution, and very likely its composition.”

Ecuador has declared an emergency in the Galapagos Islands, saying that a cargo ship which ran aground last week still poses a threat to the archipelago’s fragile ecosystem: here. See also here.

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Poas volcano in Costa Rica


Poas volcano in Costa Rica

This is a photo of Poas volcano in Costa Rica. Taken on 15 March 2014; after our departure from Alajuela.

The photos on this blog post are smartphone photos.

Poas is an active volcano. You can see smoke. The temperature in the crater lake is about 40 degrees Celsius.

Poas volcano in Costa Rica

About birds around Poas volcano: stay tuned for another post on this blog.

SCIENTISTS FIND NEW TRIGGER WARNING FOR VOLCANO ERUPTIONS “An international team of researchers has discovered a previously unknown trigger of volcanic eruptions — a finding that could give scientists a leg up on predicting blow-ups and saving lives.” [HuffPost]

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Saving Galapagos mangrove finches


This video is called: In the Galapagos, Mangrove Finches Fight On by Sue Maturin, Forest & Bird.

From the International Community Foundation:

International Community Foundation Announces World’s First Mangrove Finch Hatched in Captivity at Charles Darwin Research Station, Ecuador

In February 2014, twelve Mangrove Finch (Camarhynchus heliobates) chicks have hatched as part of a captive rearing program was born at the Charles Darwin Research Station (CDRS) in Puerto Ayora, Galapagos, Ecuador. This was the first success in the Mangrove Finch “head-start” program, which is designed to rescue the Mangrove Finch, the most threatened bird on the Galapagos Islands due to threats from nest parasites.

San Diego, CA (PRWEB) March 05, 2014

The International Community Foundation is pleased to announce that on 10th February 2014, the first Mangrove Finch (Camarhynchus heliobates) chick ever to hatch as part of a captive rearing program was born at the Charles Darwin Research Station (CDRS), the operative arm of the Charles Darwin Foundation in Puerto Ayora, Galapagos.

This was the first success in the Mangrove Finch “head-start” program, with eleven chicks having since hatched. This program is being conducted jointly by the San Diego Zoo Global (SDZG), the Charles Darwin Foundation (CDF) and the Galapagos National Park Directorate (GNPD).

This is a great effort that complements previous hard work on research and management with this species that has been carried out since 1997, by the CDF in collaboration with the GNPD.

The Mangrove Finch is the bird most threatened by extinction in the Galapagos Islands. Currently only 60 to 80 individuals are left in existence and the Mangrove Finch is classified as Critically Endangered on the International Union for the Conservation of Nature’s (IUCN) Red List of Threatened Species. Its entire population is restricted to a tiny range of less than 30 hectares in two patches of mangrove forest in the west coast of Isabela Island. In the past 5 years individuals from a remnant population at southern Isabela have no longer been found.

Since early February, 21 eggs and three newly hatched chicks were collected from wild nests in the mangrove forest at Playa Tortuga Negra, on Isabela. The eggs and chicks were then transported in an incubator, by helicopter, to the newly created incubation and hand-rearing facility at the CDRS. This is an area adapted as a quarantine facility, which aims to minimize the chance of the nestlings being infected by disease. Once out of the shell, the chick rearing process is a very demanding task, since, among other things, they need to be hand fed fifteen times a day.

Francesca Cunninghame, CDF scientist responsible for the project said: “After three years of planning and despite many challenges, we are thrilled with the achievements in every step of the process: collection of the eggs, incubation and hand rearing in captivity. Each success is a result of the great teamwork with the SDZG and GNPD and represents a milestone for the recovery of the mangrove finch wild population. The reintroduction of the youngsters back into the wild will be our next big challenge.”

Richard Switzer, Associate Director of Animal Applied Ecology from SDZG stated: “The San Diego Zoo team is very excited to collaborate in this critically important project to prevent the extinction of the Mangrove Finch. In our breeding centers in San Diego and Hawaii, USA, we have developed techniques to raise very small insectivorous birds. Being able to share these skills for the conservation of Galapagos’ biodiversity is a wonderful opportunity.”

Among many introduced species, the main threat to the Mangrove Finch is the Philornis downsi fly. This fly lays its eggs in the nests of the finches and subsequently its larvae parasitize nestlings, feeding on their tissue and blood, and causing a high mortality rate. Due to its tiny population, and with very few youngsters that manage to grow into adults, the population is simply disappearing. In addition, because the Mangrove Finch is only found in one small location, the species faces a particular risk from natural disasters such as lava flows, fire, or disease.

The Minister of Environment, Lorena Tapia, emphasized: “It is extremely important the support of various institutions, in this case the Charles Darwin Foundation and the San Diego Zoo, as due to the geographical scale of the problems we face, joint efforts are required for the conservation of a species that is seriously affected.”

The first goal of this collaboration is to implement a “head-start” program to help Mangrove Finch chicks through the major threat of Philornis. The goal is to return the young birds back to Playa Tortuga Negra, where they will be cared for in a purpose-built acclimation aviary, before being released back into the mangrove forest and monitored by the field team.

The Mangrove Finch Project is funded by SOS – Save Our Species, the International Community Foundation (with a grant awarded by The Leona M. and Harry B. Helmsley Charitable Trust), Durrell Wildlife Conservation Trust and Galapagos Conservancy. San Diego Zoo Global provides technical expertise and funding. Several private individuals have also contributed.

Scientists help Galapagos finches combat killer maggots: here.

Talking about the Galapagos; from the University of Rochester:

First-ever 3D image created of the structure beneath Sierra Negra volcano

The Galápagos Islands are home to some of the most active volcanoes in the world, with more than 50 eruptions in the last 200 years. Yet until recently, scientists knew far more about the history of finches, tortoises, and iguanas than of the volcanoes on which these unusual fauna had evolved.

Now research out of the University of Rochester is providing a better picture of the subterranean plumbing system that feeds the Galápagos volcanoes, as well as a major difference with another Pacific Island chain—the Hawaiian Islands. The findings have been published in the Journal of Geophysical Research: Solid Earth.

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