Posts Tagged ‘water’

Damn Dams risk fish extinction in U.S.

February 9, 2018

Dams drive local extinction risk of native fish in the southern United States, according to a study by Florida International University.

The high number of dams built close to each other in the southeast significantly limits where fish can move throughout their lives, driving the risk of extinction for native fish in some areas, according to a study led by FIU ecologist John Kominoski. In the southwest, dams and climate change interact to drive the risk of native fish extinction in some areas. …The restriction of water flows in rivers and streams is proving to be a real problem for fish.

The southern U.S. has experienced unprecedented population growth driving up water demands.

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Areas of No Oxygen in Ocean Waters

January 5, 2018

In the past 50 years, the amount of water in the open ocean with zero oxygen has gone up more than fourfold. In coastal water bodies, including estuaries and seas, low-oxygen sites have increased more than 10-fold since 1950. Scientists expect oxygen to continue dropping even outside these zones as Earth warms.

“Oxygen is fundamental to life in the oceans,” said Denise Breitburg, lead author and marine ecologist with the Smithsonian Environmental Research Center. “The decline in ocean oxygen ranks among the most serious effects of human activities on the Earth’s environment.”

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Sea-level rise predicted to threaten >13,000 archaeological sites in southeastern US

November 30, 2017


Sea-level rise may impact vast numbers of archaeological and historic sites, cemeteries, and landscapes on the Atlantic and Gulf coasts of the southeastern United States, according to a study published November 29, 2017 in the open-access journal PLOS ONE by David Anderson from the University of Tennessee, Knoxville, USA, and colleagues.

To estimate the impact of sea-level rise on archaeological sites, the authors of the present study analyzed data from the Digital Index of North American Archaeology (DINAA). DINAA aggregates archaeological and historical data sets developed over the past century from numerous sources, providing the public and research communities with a uniquely comprehensive window into human settlement.

Just in the remainder of this century, if projected trends in sea-level rise continue, the researchers predict that over 13,000 recorded archaeological sites in the southeast alone may be submerged with a 1 m rise in sea-level, including over 1,000 listed on the National Register of Historic Places as important cultural properties. Many more sites and structures that have not yet been recorded will also be lost.

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See also:  NASA finds Virginia metro area is sinking unevenly

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Please don’t tip over Falcon 9!

April 8, 2016

Congratulations to SpaceX for a successful launch and landing of the Falcon 9!

4.18.16 spacex lands on water

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NASA, “Oh by the way Ceres has water and is in the habitable zone”

October 7, 2015

Boring, but informative:

NASA Discovers New Gully on Mars (Photo)

March 21, 2014

By Mike Wall, Senior Writer   |   March 20, 2014 02:41pm ET

A New Gully Channel in Terra Sirenum, Mars

This pair of before (left) and after (right) images from the High Resolution Imaging Science Experiment (HiRISE) camera on NASA’s Mars Reconnaissance Orbiter documents the formation of a substantial new channel on a Martian slope between Nov. 5, 2010, and May 25, 2013. The location is on the inner wall of a crater at 37.45 degrees south latitude, 222.95 degrees east longitude, in the Terra Sirenum region. Image released March 19, 2014. Credit: NASA/JPL-Caltech/Univ. of Arizona

A NASA spacecraft has spotted a big gully on Mars, a feature that appears to have formed only within the last three years.

The powerful HiRISE camera on NASA’s Mars Reconnaissance Orbiter (MRO) imaged the channel, which is found on the slope of a crater wall in the Red Planet’s mid-southern latitudes, on May 25, 2013. The feature was not present in HiRISE photos of the area taken on Nov. 5, 2010. NASA unveiled the image on Wednesday (March 19).

“The dates of the images are more than a full Martian year apart, so the observations did not pin down the Martian season of the activity at this site,” officials wrote in a description of the gully image on Wednesday.

But, they added, “before-and-after HiRISE pairs of similar activity at other sites demonstrate that this type of activity generally occurs in winter, at temperatures so cold that carbon dioxide, rather than water, is likely to play the key role.”

However, MRO has observed other Martian features that do seem associated with liquid water — dark streaks known as recurring slope lineae.

RSL lines snake down crater walls and other slopes during warm weather on the Red Planet, and some researchers think they’re caused by briny water that contains an iron-based antifreeze. Direct evidence of flowing water at RSL sites, however, remains elusive.

If water does flow across the surface of present-day Mars from time to time, the planet would be a likelier bet to host life as we know it. Here on Earth, life teems pretty much anywhere liquid water exists.

Ancient Mars was much more hospitable to life. For example, NASA’s Curiosity rover discovered an ancient lake-and-stream system near its Red Planet landing site that could have supported microbial life billions of years ago.


Ceres asteroid vents water vapour

January 22, 2014

By Jonathan Amos Science correspondent, BBC News

Ceres impression
An artist’s impression of water out-gassing from two sources on Ceres

Observations of the Solar System’s biggest asteroid suggest it is spewing plumes of water vapour into space.

Ceres has long been thought to contain substantial quantities of ice within its body, but this is the first time such releases have been detected.

The discovery was made by Europe’s infrared Herschel space telescope, and is reported in the journal Nature.

Scientists believe the vapour is coming from dark coloured regions on Ceres’ surface, but are not sure of the cause.

One idea is that surface, or near-surface, ice is being warmed by the Sun, turning it directly to a gas that then escapes to space.

“Another possibility,” says the European Space Agency’s Michael Kuppers, “is that there is still some energy in the interior of Ceres, and this energy would make the water vent out in a similar way as for geysers on Earth, only that with the low pressure at the surface of the asteroid, what comes out would be a vapour and not a liquid.”

The quantity being out-gassed is not great – just 6kg per second – but the signature is unmistakable to Herschel, which was perfectly tuned to detect water molecules in space.

The telescope’s observations were made before its decommissioning last year.

Ceres pictured by Hubble Currently, our best image of Ceres comes from the Hubble Space Telescope

Scientists will get a better idea of what is going on in 2015, when Ceres is visited by the American space agency’s Dawn probe.

The satellite will go into orbit around the 950km-wide body, mapping its surface and determining its composition and structure.

“It will be able to observe those dark regions at high resolution, and will probably solve the question of what process is creating the water vapour,” explained Dr Kuppers.

Ceres is often now referred to as a “dwarf planet” – the same designation used to describe Pluto following its demotion from full planet status in 2006.

The asteroid’s sheer size means gravity has pulled it into a near-spherical form.

It is regarded as quite a primitive body in that it has clearly not undergone the same heating and processing of its materials that the many other objects in the asteroid belt between Mars and Jupiter have experienced.

Scientists suspect water-ice is buried under Ceres’ crust because its density is less than that of the Earth’s. And this reputation as a “wet body” is supported by the presence of a lot of minerals at its surface that have water bound into their structure.

One theory to explain why Ceres has so much more water-ice than other members of the surrounding asteroid population is that it formed further away from the Sun, and only later migrated to its present location.

This could have happened if perturbed by Jupiter, whose gravity plays a key role in corralling the asteroids in the belt they occupy today.

“We now have a more sophisticated model for the evolution of the Solar System called the Nice model, which successfully explains many of the features of the Solar System, with the planets having migrated outwards and then maybe also inwards,” said Dr Kuppers. and follow me on Twitter: @BBCAmos



Mars water surprise in Curiosity rover soil samples

September 27, 2013

By Jonathan Amos Science correspondent, BBC News Sept 26, 2013


Curiosity at Rocknest
Curiosity stopped at a location called Rocknest to sample some of the wind-blown sand and dust

There is a surprising amount of water bound up in the soil of Mars, according to an analysis done onboard the US space agency’s (Nasa) Curiosity rover.

When it heated a small pinch of dirt scooped up from the ground, the most abundant vapour detected was H2O.

Curiosity researcher Laurie Leshin and colleagues tell Science Magazine that Mars’ dusty red covering holds about 2% by weight of water.

This could be a useful resource for future astronauts, they say.

“If you think about a cubic foot of this dirt and you just heat it a little bit – a few hundred degrees – you’ll actually get off about two pints of water – like two water bottles you’d take to the gym,” Dr Leshin explained.

“And this dirt on Mars is interesting because it seems to be about the same everywhere you go. If you are a human explorer, this is really good news because you can quite easily extract water from almost anywhere.”

The dean of science at the Rensselaer Polytechnic Institute, New York, has been describing her work with Curiosity in this week’s Science In Action programme on the BBC.

The revelation about the amount of water chemically bound into the fine-grained particles of the soil is just one nugget of information to come from a series of five papers in the respected journal describing the early exploits of the rover.

Some of this data has been reported previously at science meetings and in Nasa press conferences, but the formal write-up gives an opportunity for the wider research community to examine the detail.

‘Good and bad’

Dr Leshin’s and colleagues’ publication concerns a sample analysis done at “Rocknest”, a pile of wind-blown sand and silt about 400m from where Curiosity touched down on the floor of Gale Crater in August 2012.

The robot used its tools to pick up, sieve and deliver a smidgeon of this Martian dirt to the Sam instrument hidden away inside the belly of the vehicle.

Sam has the ability to cook samples and to identify any gases that are released. These products are diagnostic of the different components that make up the soil.

So, for example, Curiosity saw a significant proportion of carbon dioxide – the likely consequence of carbonate minerals being present in the sample. Carbonates form in the presence of water.

And it saw oxygen and chlorine – a signal many had expected to see following similar studies in Mars’ “High Arctic” by Nasa’s Phoenix lander in 2008.

“[We think these] are break-down products from a mineral called perchlorate, and that’s there at about a half-a-percent in the soil,” said Dr Leshin.

“If the water was the good news for the astronauts, this is the bad news. Perchlorate actually interferes with thyroid function, so it could be a problem if humans were to ingest some of the fine dust on Mars. It’s just something we need to know about now so we can plan for it later.”

Scottish link

Three of the other Curiosity papers in the Science Magazine release also concern themselves with the nature of the Martian soil.

The fifth is a report that describes a pyramid-shaped rock found in the vehicle’s path. This striking block was dubbed Jake Matijevic, in honour of a recently deceased Nasa engineer.

The team led by Prof Ed Stopler from Caltech, Pasadena, can now confirm that Jake_M is a rock not seen before on the Red Planet.

It is most like a mugearite, says the group – a type of rock found on islands and rift zones on Earth.

“On Earth, we have a pretty good idea how mugearites and rocks like them are formed,” said co-worker Prof Martin Fisk from Oregon State University, Corvallis.

“It starts with magma deep within the Earth that crystallises in the presence of 1-2% water.

“The crystals settle out of the magma and what doesn’t crystallise is the mugearite magma, which can eventually make its way to the surface as a volcanic eruption.”

Mugearite was first identified on Earth by British petrographer/petrologist Alfred Harker. The name references a local croft, Mugeary, on the Isle of Skye, just off the Scottish mainland.

The Curiosity rover is currently engaged in some hard driving in Gale Crater. Since early July, it has been rolling tens of metres a day.

The robot is trying to reach the foothills of the large mountain that dominates the centre of the deep, equatorial impact bowl. and follow me on Twitter: @BBCAmos

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