Stories tagged Earth Buzz


Another tidal generator: But this one is hiding underwater. This is why I didn't know what they look like.
Another tidal generator: But this one is hiding underwater. This is why I didn't know what they look like.Courtesy Fundy
Along with wind and solar, harvesting power from tidal forces comes up a lot in discussions of alternative energy sources.

Was that a horrible sentence? I think it was. What I meant to say is this: we can generate electricity from tides, and lots of it. "Tidal power" is often brought up alongside solar power and wind power, but while I can easily picture windmills and solar panels, I'm not always sure what sort of device we'd use to harness the power in the tides.

This sort of device! For those of you too afraid to click on a strange link (who knows... I could be linking to an image like this!), the article depicts something that looks sort of like a thick, stubby windmill, with blades on its front and back. It's a tidal turbine, and at 74 feet tall and 130 tons it's the world's largest. It should be able to supply electricity to about 1,000 households. Pretty impressive.

Tidal turbines, apparently, are so productive because water is so much denser than water, and so it takes a lot more energy to move it. An ocean current moving at 5 knots (that's a little shy of 6 miles per hour, for the landlubbers) has more kinetic energy, for example, than wind moving at over 217 miles per hour.

At least according to that article, the United States and Great Britain each have enough tidal resources (areas where this kind of generator could be installed) to supply about 15% of their energy needs.

More info on the tidal turbine, which I am calling "the Kraken," because it's big, underwater, and will occupy your mind for only a very short time.


A new record hail stone fell on 23 July 2010 near Vivian SD!

It is 8-inch in diameter hail stone and weighs 1.9375 pounds.

The old record heaviest U.S. hailstone was a 1.67-pound found near Coffeyville, KS on Sep. 3, 1970. The old record for the largest diameter hailstone was 7 inches found in Aurora, NE on June 22, 2003. This Aurora, NE hailstone still holds the U.S. record for circumference: 18.75 inches. The Vivian, SD hailstone circumference was only 18.5".

Here is a photo of the stone

Hail is precipitation in the form of large balls or lumps of ice. Hailstones begin as small ice particles that grow primarily by accretion. The production of large hail requires a strong updraft that is tilted and an abundant supply of supercooled water. Because strong updrafts are required to generate large hailstones, it is not surprising to observe that hail is not randomly distributed in a thunderstorm; instead it occurs in regions near the strong updraft. Supercell thunderstorms, in which the strongest updrafts are created with help from the mesocyclone, often produce the largest hail.
Eventually, though, the weight of the hailstone overcomes the strength of the updraft, and it falls to earth. The curtain of hailstones that falls below the cloud base is called the hailshaft. These regions are often said to appear green to observers on the ground, although recent research suggests that heavy rain as well as hail can create this optical phenomenon. As the storm moves, it generates a hailswath, a section of ground covered with hail.

Hailstorms can severely damage crops, automobiles, and roofs. Sometimes the swath can be so big you can see it on the ground from a satellite

The Guthrie Theater: Come visit this state-of-the-art theater right here in Minneapolis!  This weekend, see Macondo, a play about the BP oil spill for only $10/ticket.

Whether you've been following the Deepwater Horizon (BP) oil spill or not, if you like theater, have I got a show for you!

A friend turned me on to Macondo playing at the Guthrie theater through this weekend (last show is Sunday, Aug. 1st at 1:00pm). The play is A Guthrie Experience for Actors in Training production, so tickets are only $10/each. I've posted the Guthrie's description of the play below, but if you want more information or to reserve your tickets, click here.

"Macondo is a place of myth, a place where oil spills under and over water, creating a chain reaction that devastates human lives and animal habitats. It is also the name of the ruptured BP undersea oil field and oil well responsible for the current Gulf of Mexico spill. The gods awake from their slumber and intervene in this dramatically unfolding story that currently weaves itself through the fabric of our lives."

The National Research Council’s conceptual framework which will guide the development of next generation standards for science education has just been released (today) for public comment.

Here is the link-


Tropical Storm Alex, which formed over the northwestern Caribbean Sea out of a westward-moving tropical wave on Friday and Saturday (June 26 and27), emerged overnight into the Bay of Campeche from the Yucatan Peninsula. Since emerging from that landmass as a tropical depression (signifying sustained winds weaker than 35 knots), it has strengthened back to Tropical Storm status. Current forecasts place it as a hurricane — possibly major — near the northern Mexico Gulf Coast later this week.


NCED researchers studying delta dynamics in coastal Louisiana
NCED researchers studying delta dynamics in coastal LouisianaCourtesy National Center for Earth-surface Dynamics
The Mississippi River has turned out to be a big, muddy, silent hero in the fight to save Louisiana's wetlands from the oil spill.

It turns out that many scientists believe that the flow of fresh water from the Mississippi River into the Gulf of Mexico has thus far kept the oil slick offshore and out of wetlands.

Guerry Holm, a researcher with the National Center for Earth-surface Dynamics (NCED) tells me that the flow of the Mississippi River has been at a relatively high stage for the past two months and that the river's high volume of freshwater has acted as a hydrologic barrier, keeping oil from moving into the Mississippi Delta wetlands from the sea. Holms is now studying how two river characteristics—the slope of the water surface from the river delta to the sea and the time it takes water to move through a wetland to the sea—help mitigate oil contamination of the wetlands.

Holm is collaborating on the research with NCED Principal Investigator Robert Twilley, who is also busy addressing an immediate concern: the flow of the Mississippi tends to drop seasonally, starting in June. If that happens and Mississippi water flow into the delta decreases, Twilley, Holm, and others worry that oil will reach more of the wetlands sooner.

To address these concerns, some area scientists are proposing to shift the flow of water between the Mississippi and a river in Louisiana it feeds called the Atchafalaya. Twilley supports the idea: "We've been in conversation with U.S. Army Corps of Engineers and the state [of Louisiana] about how to manage the river as a protection system," Twilley reports.

Unfortunately, the river flow adjustments may be difficult to accomplish for political reasons. The diversion structure used to control flow between the Mississippi and Atchafalaya Rivers is controlled by Congress. Earlier proposals to send more water down the Mississippi have been met with resistance.


I see the American Museum of Natural History in NY is going to have an exhibit on the Scott and Amundsen 'race' to the South Pole. (See NYTimes Art section: ). I look forward to seeing that exhibit.

Being a weather guy.... Dr. Susan Solomon, a senior scientist at the NOAA and an IPCC author, has a book (The Coldest March: Scott`s Fatal Antarctic Expedition) that indicates that an unusually cold Antarctic autumn contributed to the death of Captain Robert F. Scott and his four comrades on their 1500-kilometer (900-mile) trek back from the South Pole in March 1912. Temperatures were 10° to 20° colder than expected during the race to the South Pole. The cold weather cut in half the distance the explorers could travel in a day. A blizzard trapped them in a tent, where they froze to death 18 kilometers (11 miles) from a supply depot.

Another fact I find interesting, is that the Scott expedition revealed that Antarctica once basked in warmth. Among the 16 kilograms (35 pounds) of rocks the expedition collected were fossils of Glossopteris, a seed fern. This fossil is scientific evidence that the current ice-covered continent was once fertile.


I enjoy working with our team to develop on-line interactive education activities. We are in the final testing of whose goal is to teach about the balance of global water, land coverage, atmosphere and cloudiness required to create a "liveable planet". If you want to play with it and give us feedback - here is the link:
The goal is to make a habitable planet by adding enough water, atmosphere and clouds to reach a global average temperature of about 15°C (59°F). You can mix and match, add or remove.

* Drag (and drop) an item from the right side to the left to add that element
* Drag (and drop) from the left are back to the right to remove that element
* HINT You must put at least 3 clouds by the planet!!

There is a timer to see how fast you can make the planet livable.

It's not every day that I agree with the NYTimes' John Tierney. But today, I do. He offers up seven rules for a new breed of environmentalist: the "Turq."

"No, that’s not a misspelling. The word is derived from Turquoise, which is Stewart Brand’s term for a new breed of environmentalist combining traditional green with a shade of blue, as in blue-sky open-minded thinking. A Turq, he hopes, will be an environmentalist guided by science, not nostalgia or technophobia."

Check out the rules. Are you a Turq? Does any of Tierney's advice surprise you?

Earth Day
Earth DayCourtesy Cornelia Kopp

Jon Foley, of the University of Minnesota's Institute on the Environment, has similar advice. "There are no silver bullets," he says. "But there is silver buckshot."

Human activities, rather than nature, are now the driving force of change on the planet. And experts say that there will be nine billion of us on the planet by 2050. Making sure that we all have the chance to survive and thrive will require a lot of innovation, and a lot of blue-sky thinking. Who's up for the challenge?


Is this house a biogeochemical hotspot?
Is this house a biogeochemical hotspot?Courtesy
To ecologists who study the environment, cities and suburbs are fascinating places. For one thing, they're full of people, and people take-up space, consume materials and energy, and create waste every single day. When people do this together in concentrated areas like cities and suburbs, they create what scientists call "biogeochemical hotspots" - places where chemical and energy reaction rates are much faster than in surrounding areas.

Individual houses are also hotspots. A group of scientists at the University of Minnesota, led by researchers Sarah Hobbie and Kristen Nelson, are trying to understand more about urban ecosystems and how chemicals and energy cycle through different people's homes.

They've begun to study a small group of people whose homes are here in Minnesota - asking them questions about their behavior and taking surveys and samples on their property.

What they've found might surprise a few people. It turns out that not everyone uses energy and chemicals the same way. Small numbers of individuals and families consume and waste much more than others - creating a bigger footprint in their ecosystem.

So who are these disproportionate polluters? There is a lot that scientists still don't know, especially about why people make the choices they do, but one thing seems to be clear - generally speaking, the more money that a family makes, the bigger their ecological footprint.

These bigger impacts come from a few behaviors that wealthier Americans tend to exhibit more than their less-wealthy counterparts. Flying in airplanes, buying a much larger home, having more pets and driving a car more often all contribute to a family's impact on their ecosystem.

While studying the role individuals play in urban ecosystems, another thing these scientists found to be true was that small individual actions - for example, turning down the thermostat in the winter just a few degrees, or using less chemicals on lawns, did have a significant impact on the environment.

You can see a recording of two of the researchers involved this study .