Tuesday, March 27, 2012

Wild life in the Hawaiian deep: new photo archive

When you get down into the deep ocean, it’s not just more of the same.

The creatures of the deep are different—so different that some don’t even look like creatures.

(Images: A couple of shots from the Hawai`i Undersea Research Laboratory deep sea creature collection include the outrageously spiky crab Lethodidae neolithodes and the impressively patterned starfish Pentaceraster cumingi. Credit: HURL.)

To help understand the amazing diversity of deep ocean life around the Islands, the Hawai`i Undersea Research Laboratory (HURL), which has been photographing them for more than 30 years, has created an online identification guide.

The resource was once access-limited to scientists—it is loaded onto iPads that submersible staffs can take along for critter identification--but is now publicly available, here.

You’ll find there more than 1,500 images, some of them still shots and others taken from videos, that have been collected during deep dives by the University of Hawai`i’s various manned and remotely operated submersibles.

A press release with more details on the program is available here.

© Jan TenBruggencate 2012

Wednesday, March 21, 2012

Mercury and Venus used to gauge the Sun

Captain James Cook more than two and a quarter centuries ago voyaged to Tahiti to view the transit of Venus across the face of the sun, in attempt to gauge the size of the solar system.

There is a cool NASA article about that here.

(Image: Images of Mercury’s path across the face of the sun, as viewed from NASA’s Solar and Heliospheric Observatory (SOHO) on November 8, 2006. Credit: NASA.)

Scientists are still doing that kind of seminal work, and researchers from Hawai`i, Brazil and California have just announced that the 2003 and 2006 transits of Mercury across the sun, measured from the SOHO satellite, have yielded the most accurate ever calculation of our sun’s size.

The radius of the sun is 432,687 miles, give or take 40 miles, they say.

Using a satellite gave the researchers a great advantage over Cook, since they could overcome the blurring caused by the Earth’s atmosphere. The researchers included Jeff Kuhn and Isabelle Scholl of the University of Hawai`i Institute for Astronomy, Brazilian astronomer Marcelo Emilio, who was visiting the Hawai`i institute, and Rock Bush of Stanford University.

And while they used Mercury for the latest measurement, they plan to observe the transit of Venus June 5, in an attempt to improve the accuracy of their measurement even more. Their paper on the work is here.

© Jan TenBruggencate 2012

Saturday, March 17, 2012

Wave energy potential massive for Hawai`i, but...

Forget land-based electricity sources like geothermal, wind and solar—the Electric Power Research Institute says Hawai`i could easily produce all its power from waves.

Its new study, “Mapping and Assessment of the United States Ocean Wave Energy Resource,” the agency says Hawai’i has the potential to produce 130 theoretical terawatt-hours of power annually from wave energy. And 80 terawatt-hours annually of actually recoverable power.

The report was prepared for EPRI by the Virginia Tech Advanced Research Institute and the National Renewable Energy Laboratory.

There remain significant issues for wave energy, including that there’s no robust wave energy collection technology that yet has a long history of actual energy production. There are, however, many companies with some really interesting technological approaches.

This 2009 report from the Hawai`i Clean Energy Initiative doesn’t even list wave power as a renewable energy source.

One of the issues for Hawai`i is that the system that’s going to work may not be one that requires waves come reliably from a single direction. Says the report: “The Hawaii region experiences a greater vaiety of orientations and prevailing wave directions than the US mainland West Coast...”

And there’s the whole issue of whether wave energy in a particular location, even though it is “technically recoverable,” is actually something in a place you’d want to have a wave generation unit.

And there’s the question of how quickly wave energy can become a part of our energy mix. If you go to this U.S. Energy Information Service Administration website, you find an estimate that Hawaii was expected to have 2.7 megawatts of wave energy production in place by the end of last year. Hopeful forecasts are rampant in the energy field, and this appears to have been another.

Still, there’s a lot of theoretical potential in wave energy. Total installed capacity of all the utilities in Hawai`i today is between 2 and 3,000 megawatts. If all of that were producing at 100 percent all the time, it would produce on the order of 20 terawatt-hours—a fraction of the 80 terawatt capacity EPRI says is possible from waves alone.

© Jan TenBruggencate 2012

Thursday, March 8, 2012

Crown of Thorns starfish invasions are local, not alien

When crown-of-thorns starfish invade a reef in numbers, the results are devastating.

It’s been assumed that they show up like alien invaders, their larvae washing in from elsewhere and taking rapacious advantage of a virgin reef. But new evidence suggests that’s not the case.

(Image: A line of crown-of-thorns starfish grazing on a reef. Credit: Molly Timmers, NOAA.)

The new genetic work shows that most outbreaks seem to be sourced in the native starfish population—that perhaps something has changed in their environments to suddenly give them a massive opportunity to burgeon.

As Walt Kelly wrote for Pogo, “We have met the enemy and he is us.”

A copy of the new research is available here.

The paper was written by Molly A. Timmers of NOAA’s Pacific Islands Fisheries Science Center, Chris Bird, Rob Toonen and Derek Skillings of the Hawai`i Institute of Marine Biology at the University of Hawai`i, and Peter Smouse of Rutgers University’s Department of Ecology, Evolution and Natural Resources.

Crown-of-thorns sea stars, Acanthaster planci, are notorious for their massive population explosions. They eat vast amounts of live coral, changing the very character of the reef, promoting seaweed growth, changing fish populations and creating cascades of changes.

In Hawai`i, outbreaks have been attacked by divers with toxic syringes, injecting individual animals. In Australia’s Great Barrier Reef, outbreaks often occur in vast waves, working their ways down the length of the reef.

The team of scientists conducted genetic tests on the sea stars, only to find that they tended to be home-grown, not outsiders,

“This research has proved that outbreaks are not some rogue population that expands and ravages across central Pacific reefs. Instead, the authors hypothesize that nutrient inputs and favorable climatic and ecological conditions likely fuel outbreaks of local populations,” said a press release from the University of Hawai`i.

Why is this information useful? Because a lot of the response to the outbreaks tends to focus on killing the starfish themselves rather than attacking the cause of the population increase,

“This study is the first genetic survey of (crown-of-thorns) populations in which both outbreak and non-outbreak populations are surveyed across a broad region of the Pacific and the results are pretty clear that outbreaks are not jumping across large expanses of open ocean,” the release said.

The paper itself concludes: “Overall, outbreaks that occur at similar times across population partitions are genetically independent and likely due to nutrient inputs and similar climatic and ecological conditions that conspire to fuel plankton blooms.”

In plainer English, co-author Rob Toonen, of the Hawai‘i Institute of Marine Biology, said, “Our recommendation to managers is to seriously consider the role that environmental conditions and local nutrient inputs play in driving (crown-of-thorns) outbreaks,” said

© Jan TenBruggencate 2012