Stories tagged Earth Structure and Processes

May
12
2011

Mississippi River Levee in Baton Rouge, LA, taken May 11th 2011.: Panorama of the Mississippi River levee in Baton Rouge, LA near Louisiana State University, taken May 11th 2011.
Mississippi River Levee in Baton Rouge, LA, taken May 11th 2011.: Panorama of the Mississippi River levee in Baton Rouge, LA near Louisiana State University, taken May 11th 2011.Courtesy Azure Bevington
You might have heard about the terrible flooding that is occurring all along the Mighty Mississippi. As I write this I am sitting in Baton Rouge, Louisiana hoping the levees will hold. Normally the river in Baton Rouge is far below the tops of the levees. Flood stage, which is the water level at which the river would begin to flood surrounding areas without the levees acting as barriers, is 35 ft. Right now the water level is 42.8 ft and has risen 8 ft in just the last week. It is projected to crest at 47.5 ft and remain at that level for 8 to 10 days; this is higher than the previous record set in May 1927 of 47.28 ft. The tops of the levees that protect Baton Rouge are between 47 and 50 ft, they are currently sandbagging in areas less than 48 ft. Besides the possibility of overtopping there are also other problems that we need to look out for. When the river level remains high for an extended period of time the water can seep in and begin to saturate the soil, this can possibly weaken the levee structure. There is also the possibility of water going under the levee; this can result in sand boils, where the water bubbles up through the soil. It is very unlikely that this will happen, as the levees are strong and well constructed, but we need to be on the lookout for any problems.

Here in Baton Rouge we are much better off than many who live in communities within the Atchafalaya Basin, where the expected opening of the Morganza spillway could cause flooding of over 3 million acres (Click here to see a map of projected flooding in the basin) Many of these folks have already begun to sandbag their homes and to prepare to leave the area. The Morganza spillway is a large controlled gated structure that will divert water from the Mississippi River into the Atchafalaya Basin. The Atchafalaya Basin is a low lying cypress swamp that normally receives 30% of the flow of the Mississippi River through the Old River Control structure through the Atchafalaya River that winds its way through the swamp. This flood is projected to be larger than the 1973 flood and possibly even larger than the 1927 flood that devastated communities along the river, and brought about the passage of Flood Control Act of 1928. The magnitude of this year’s flood has already resulted in the opening of the Bonnet Carré spillway which diverts water into Lake Pontchartrain, this reduces the water levels as the River flows past New Orleans.

Stay tuned for updates on the flooding in Louisiana.

Have any of you been affected by the flood waters?

May
02
2011

the ocean's 5 major gyres
the ocean's 5 major gyresCourtesy NOAA
We often talk about the ocean ecosystem. And, indeed, there is really just one, world-wide ocean, since all oceans are connected. An Indian Ocean earthquake sends tsunami waves to distant coasts. Whitecaps look as white anywhere in the world. The ocean swirls in similar patterns.

However, oceanographers do find differences from place to place. For example, let’s take a closer look at the chemistry of two swirls, or gyres as they’re more properly called. Scientists have found a micro difference between the North Atlantic Gyre and the North Pacific Gyre. The Atlantic generally has really low levels of phosphorus, measurably lower than the North Pacific Gyre.

the element phosphorus among its neighbors in the Periodic Table of the Elements
the element phosphorus among its neighbors in the Periodic Table of the ElementsCourtesy modified from Wikipedia
Phosphorus is a very important element in living things. For example, it’s a necessary ingredient in ATP (adenosine tri-phosphate), the energy molecule used by all forms of life. Phosphorus is picked up from seawater by bacteria. All other marine life depends upon these bacteria, either directly or indirectly, for P. Therefore, if you’re bacteria living in the impoverished North Atlantic Gyre, you’d better be really good at getting phosphorus.

And they are!

Oceanographers at the Center for Microbial Oceanography: Research and Education (C-MORE) at the University of Hawai`i have made an important discovery. C-MORE scientists Sallie Chisholm, based at the Massachusetts Institute of Technology and her former graduate student Maureen Coleman, now a scientist at the California Institute of Technology, have been studying two species of oceanic bacteria. Prochlorococcus is an autotrophic bacterium that photosynthesizes its own food; Pelagibacter, is a heterotrophic bacterium that consumes food molecules made by others.

Pacific HOT and Atlantic BATS Stations: Microbial samples were collected at each location.
Pacific HOT and Atlantic BATS Stations: Microbial samples were collected at each location.Courtesy C-MORE
Drs. Chisholm and Coleman took samples of these two kinds of bacteria from both the Atlantic and Pacific Ocean. The Atlantic samples were collected by the Bermuda Atlantic Time-Series (BATS) program. The Pacific samples were collected in the North Pacific Gyre (about 90 miles north of Honolulu) by the Hawai`i Ocean Time-Series (HOT) program. The scientists discovered surprising differences in the genetic code of the bacteria between the two locations:

  • First of all, the Atlantic populations of both bacterial species have more phosphorus-related genes compared to their Pacific cousins. (Picture Atlantic microbes in Superman outfits with a big "P" on their chests!)
  • Secondly, in the Atlantic, Prochlorococcus has different kinds of P-related genes compared to Pelagibacter. Perhaps this means the two microbial species have evolved over time to use different phosphorus sources, to avoid competing with one another for this limited resource.

Drs. Chisholm and Coleman have discovered important micro differences between bacteria of the same species in two oceanic gyres. Now we can better understand how these microbes are working to recycle an important nutrient beneath the whitecaps.

Reference: October 11, 2010 issue of the Proceedings of the National Academy of Sciences

Mar
17
2011

Aren’t budgets all about money? Don’t they track how many $$$ come in and how many $$$ go out?

That’s right; so what’s a carbon budget? A carbon budget tracks how much carbon, C, goes in and out of a natural area.

Right now, we’re worried about too much C going into our planet’s atmosphere. This excess C is causing global warming, sea level rise, ocean acidification and other environmental problems. These are BIG problems! We can begin to fix these problems if we do a carbon budget and really know how much carbon is where.

Carbon Budget Study Area: How much carbon is in the shallow, coastal seawater?
Carbon Budget Study Area: How much carbon is in the shallow, coastal seawater?Courtesy Sergio Signorini, North American Carbon Program
Along with others, scientists at the Center for Microbial Oceanography: Research & Education (C-MORE), based at the University of Hawai`i, have begun to track C in the ocean off the eastern United States. The study area includes a LOT of water! -- all the seawater from high tide out to 500 meters deep, shown by the black line in the map, in the Gulf of Maine (GoM), the Mid-Atlantic Bight (MAB), and the South Atlantic Bight (SAB.)

Imagine your money budget. Let’s say we track your $$$ in and out of 4 categories. Money comes into your pocket from 2 categories, mowing the neighbor’s lawn and babysitting. Money goes out when you pay for movies and snacks.

In the same way, scientists want to track C as it moves between the coastal water “pocket” and 4 nearby areas: the coastal land, the atmosphere above, seafloor below, and the deeper ocean offshore. Where is C leaving the coastal water? Where is it entering?

But wait! Coastal zones are only small slivers of water, compared to the open ocean around the world. Why bother to track carbon in coastal waters?

Ah ha! Coastal waters are very important in C budgeting. Notice the red color in the map above. Red means there's a lot of chlorophyll. Chlorophyll is the green pigment important in photosynthesis, the process that plants use to take in C and fix it as sugar. The red in the map shows that coastal waters are richer in carbon than the open ocean.

Understanding the C budget of coastal waters is one small but important step in solving global warming and other environmental problems.

Reference: Ocean Carbon & Biogeochemistry Winter 2010 OCB Newsletter; Vol. 3, No. 1.

Feb
10
2011

Lisa Jackson: The head of the EPA met with House Republicans recently to discuss carbon regulation.
Lisa Jackson: The head of the EPA met with House Republicans recently to discuss carbon regulation.Courtesy EPA
I'm assuming that you aren't at home watching dense legal proceedings related to the regulation of molecules in our atmosphere. So here's the timeline of a recent important story.

  1. Humans figure out how to turn things (engines, turbines) by burning coal and petroleum. This makes like life a whole lot better in lots of ways.
  2. Scientists figure out that, all that burning is causing some problems. When we burn that stuff, we put carbon in the atmosphere and that's disrupting the natural climate system leading to all kinds of problems.
  3. Some different humans hear about this science and think we should pass a law. This law should put some limits on how much carbon we put into the atmosphere.
  4. The humans in the Republican controlled House don't like this idea, because they think these limits would cripple the economy. Oh, and some of them don't even believe the scientists. Since these Republicans are in charge right now, no new law.
  5. The humans over at the Environmental Protection Agency, who are mostly scientists, notice that they should already be regulating all this carbon, because of an existing law, the Clean Air Act.
  6. The Supreme Court agrees
  7. The House Republicans, disagree and call a hearing with the head of the EPA.
  8. Who knows what's next...

OK, you're up to date. Unfortunately the media is framing this issue in military terms. "The coming battle." "EPA and Republicans spar over climate change." "EPA blocks Republican rocket launcher with sweet ion science shield." Yeah, I made that last one up. But we don't need battles, we need conversations and action.

My point is that this issue is a great opportunity to have a discussion about how science is used in our public policy decisions. Do you think the EPA is too focused on the scientific findings related to climate change? Are they ignoring the economic impacts? Are you frustrated with some of the Republican views that outright deny the scientific findings on what's causing climate disruption? Are they ignoring real facts? Could this issue be alleviated by better science education?

Feb
07
2011

Mt. St. Helens erupts in 1980: Yellowstone's supervolcano has erupted with one thousand times the power of the blast pictured here.
Mt. St. Helens erupts in 1980: Yellowstone's supervolcano has erupted with one thousand times the power of the blast pictured here.Courtesy USGS/Cascades Volcano Observatory
The gigantic volcano seething under Yellowstone National Park could be ready to erupt with the force of a thousand Mt. St. Helenses! Large parts of the U.S. could be buried under ash and toxic gas!

Or, y'know, not.

This story has popped up in a couple of places recently, including National Geographic's website and, more sensationally, the UK's Daily Mail. Shifts in the floor of Yellowstone's caldera indicate that magma may be pooling below the surface, a phenomenon that might be the very earliest stages of an eruption. Then again, it's difficult to predict volcanic eruptions with much accuracy because there's no good way to take measurements of phenomena happening so far below the earth's surface.

Incidentally, the contrast in tone between the two stories makes them an interesting case study in science reporting: The Daily Mail plays up the possible risk and horrific consequences of an eruption, while National Geographic is much more matter-of-fact about the remoteness of that possibility. Which do you think makes better reading?

Jan
28
2011

ocean micro-plastic: These samples were collected from the surface water of the North Pacific Ocean by the SUPER expedition in 2008.
ocean micro-plastic: These samples were collected from the surface water of the North Pacific Ocean by the SUPER expedition in 2008.Courtesy C-MORE
Who hasn’t heard that plastic in the ocean is trouble?

  • Plastic has been found clogging the stomachs of dead albatross and other ocean birds.
  • Plastic ropes and traps have entangled marine life, causing more death.
  • As a long-lasting chemical, plastic floating in the ocean provides long-distance rafts that may move aggressive alien marine life to new areas.
  • Plastic may provide a “sticky” surface where toxins can accumulate, becoming a concentrated source of poison for marine consumers.
  • A "Great Pacific Garbage Patch" has been reported to be an "island the size of Texas" floating in the North Pacific Ocean...but is this really true? Continue reading to find out!

Yep, plastic in the ocean is bad news; so let’s put scientific energy into studying and solving the problem.

manta trawl: The trawl is hoisted above the stern deck of the RV Kilo Moana.
manta trawl: The trawl is hoisted above the stern deck of the RV Kilo Moana.Courtesy C-MORE
In 2008 C-MORE, the Center for Microbial Oceanography: Research & Education headquartered at the University of Hawai`i, with assistance from the Algalita Marine Research Foundation, embarked on an oceanographic expedition aboard the RV Kilo Moana, which means "oceanographer" in Hawaiian. The goal of the expedition, dubbed SUPER (Survey of Underwater Plastic and Ecosystem Response Cruise), was to measure the amount of micro-plastic in the ocean. In addition, oceanographers took samples to study microbes and seawater chemistry associated with the ocean plastic. The Kilo Moana sailed right through the area known as the “Great Pacific Garbage Patch,” between Hawai`i and California.

Early results: there was no garbage patch/island. Once in a while something like a barnacle-covered plastic buoy would float past the ship, but mostly the ocean looked really clean and empty of any kind of marine debris.

manta trawl: The net is being pulled slowly through the ocean's surface water.
manta trawl: The net is being pulled slowly through the ocean's surface water.Courtesy C-MORE
But wait! Scientists looked closer and were amazed. Every single one of the more than a dozen manta trawls, filtering the surface seawater for an hour and a half each, brought up pieces of micro-plastic! Some were as small as 0.2 millimeter, mixed among zooplankton!

Other expeditions have reported similar results (for example, Scripps Institution of Oceanography's 2009 SEAPLEX expedition and Sea Education Association's North Atlantic Expedition 2010): no Texas-size garbage patches, but plenty of plastic marine debris to worry about. The data seem to show that most of the plastic is in the form of small pieces spread throughout upper levels of water at some locations around the world's ocean. In these areas, the ocean is like a dilute soup of plastic.

Dr. White: examining the results of a manta tow
Dr. White: examining the results of a manta towCourtesy C-MORE
C-MORE researcher Dr. Angelicque (Angel) White, assistant professor of oceanography at Oregon State University (OSU) was a scientist on board the SUPER expedition. In recent interviews, (for example: the Corvallis Gazette-Times and Seadiscovery.com) Dr. White cautions us to view the complex plastic marine debris problem accurately. Furthermore, new results will soon be published by C-MORE about microbial diversity and activity on plastic pieces.

In the meantime, as Dr. White says, “…let’s keep working on eliminating plastics from the ocean so one day we can say the worst it ever became was a dilute soup, not islands. “

Plastic in the ocean is trouble. How can you be part of the solution?

Jan
12
2011

You know what I think makes humans unique? Our ability to solve problems. Ingenuity. Our can-do attitude. Throughout history, if we found a problem, we sought a solution. Too cold at night? Fire. Killing a mammoth with your hands too deadly? A team of spearman. Flash forward thousands of years and our problems became more sophisticated. Horse and buggy too slow? Automobiles. Candlelight not bright enough? Light bulbs. Washing laundry and dishes too tedious? Washing machines and dishwashers. Typewriters cramping your style? Computers. Computers cramping your style? Android phones. (Have you caught my drift? Good.) Now, some of our solutions are becoming new problems. Cars and electricity emit pollutants and greenhouse gases. Washing machines and dishwashers are using too much water. Computers and cell phones require the mining and eventual disposal of toxic metals. Once again, it’s time for some good ol’ human problem solving.

A Literal Eco-Footprint: Somehow, I don't think this is exactly what Sarah Hobbes and team had in mind.
A Literal Eco-Footprint: Somehow, I don't think this is exactly what Sarah Hobbes and team had in mind.Courtesy urje's photostream (Flickr)

Sarah Hobbes and her collaborators identified a problem: we aren’t doing enough to reduce our household ecologic footprints, especially regarding carbon. Now, they’re working on a solution by researching what influences families to change their living habits and minimize their footprint. This past Sunday’s edition of the Star Tribune covered Sarah’s research story (the Buzz’s own Liza was even quoted!). Sarah Hobbes is an ecologist at the University of Minnesota and a resident fellow at the Institute on the Environment. Her research project doesn’t take place in a lab, but rather in peoples’ home – including the St. Paul house Sarah shares with her husband (also a University of Minnesota ecologist) and two children. The research team uses a 23-page survey to understand what kind of ecological footprint Ramsey and Anoka county homes are leaving. (Btw, kudos to those of you who already completed the lengthy survey! Science really appreciates people like you.)

Some of the initial results aren’t surprising: While most of us really do care about the environment,

“For most families, cost and convenience are more important than concern about the environment. People in the suburbs tend to use more fertilizer than those in the urban core. People with bigger houses and bigger families had a bigger carbon footprint, as did people who drove farther to work.” (Star Tribune article)

But what’s most interesting is that competition really gets us going. That is, respondents were motivated to reduce their ecological footprint after they compared their own rank to their neighbors’. Larry Baker, a project collaborator, stated,

“We expect that attitudes will drive 10 or 20 percent of the carbon emissions… If we could reduce energy use by 20 percent, that would be a huge benefit.” (Start Tribune article)

No kidding! That would be fantastic!! The full survey report hasn’t been published yet, but I’m sure looking forward to the recommended solution.

Want to know your ecological footprint? Try out this online Ecological Footprint Quiz.

Dec
16
2010

I was not even a thought in the 1970s, but I've heard it was a pretty good time to be a rock. People took you as their pets, and I'll bet Professor Lawrence Edwards had a couple Pet Rocks back in the day.

Family Portrait: From left to right: Momma Igneous, Baby Sedimentary, and Poppa Metamorphic.
Family Portrait: From left to right: Momma Igneous, Baby Sedimentary, and Poppa Metamorphic.Courtesy Wikimedia Commons

You see, Edwards is an isotope geochemist, which sounds just about as awesome as it is: he studies the teeny tiny radioactive elements in rocks. These elements help Edwards date rocks. No, that doesn't mean he wines and dines them. Quite the opposite! Edwards developed a sneaky way to figure out how old they are (and let me tell you, nobody wants to be reminded of their age when they're hundreds of thousands of years old).

Edwards' method is similar to carbon-14 dating, only way better. In certain kinds of rocks, Edwards can date rocks as old as 500,000 years compared to carbon-14's measly 50,000 years. That's a whole order of magnitude older! Here's how Edwards' method works: Scientists know that half of any quantity of uranium decays into thorium every 245,500 years. Edwards uses a mass spectrometer to measure the ratio of two radioactive elements -- uranium and thorium. Then, Edwards compares the present ratio of uranium to thorium to what scientists would expect from the half-life decay and bada-bing, bada-boom! Simply genius.

Why am I getting all hyped up over some old rocks? Because they're helping us learn more about ourselves and the tenuous place we hold in this world. For example, Edwards has used his super-special method to trace the strength of monsoon seasons in China. Turns out weak monsoon seasons correlate with the fall of several historical dynasties, and strong monsoons correlate with climatic warming in Europe. Edwards calls this work,

"the best-dated climate record covering this time period."

Dec
09
2010

Surveying Microbes at Sea
Surveying Microbes at SeaCourtesy C-MORE
There are microbes…and then there are micro-microbes. Oceanographers on C-MORE’s BiG RAPA oceanographic expedition are finding bacteria the size of one-one-millionth of a meter in the oligotrophic (low nutrient), open-ocean of the Southeast Pacific, far from the productive waters off the coast of Chile. But that’s not all; some scientists are looking for the even smaller marine viruses in gallons of filtered seawater. Meet some of these micro-microbes in these video reports:
Prochlorococcus
ProchlorococcusCourtesy Dr. Anne Thompson, MIT

  • Microbe Diversity, Part 1: Prochlorococcus, the most common bacterium in the world’s oceans; nitrogen-fixing bacteria that provide a usable form of nitrogen “fertilizer” for other photosynthesizers
  • Microbe Diversity, Part 2: picophytoeukaryotes with different colored pigments; viruses, which are parasites on other living things

Yes indeed, microbial oceanographers are taking home quite a collection from the South Pacific Ocean. In less than a week the good ship RV Melville will arrive at Rapa Nui (Easter Island), and scientists will step onto land for the first time in almost a month. They and their oceanographic samples will return to C-MORE laboratories around the U.S. The oceanographers are also returning with new hypotheses buzzing around in their heads. Now it’s time for them to take the next step in the Scientific Method: data analysis!

Nov
26
2010

surveying microbes at sea
surveying microbes at seaCourtesy C-MORE
Dr. Dan Repeta from the Woods Hole Oceanographic Institution (WHOI) is C-MORE’s Chief Scientist on the BiG RAPA expedition, which is conducting research off the coast of Chile. Dr. Repeta and his team of scientists are sampling the underwater microbial environment using a variety of instruments, including a water collector called a CTD (see educational resource below). Two interesting results have turned up in the CTD data:

  1. chlorophyll -- The greatest amount of the green pigment, representing floating microscopic plants in the sea known as phytoplankton, was found about 30 meters below the sea surface. (That's where oceanographers expect the most chlorophyll. Perhaps phytoplankton living at that depth must produce more chlorophyll in order to capture the lower light intensities, just like leaves are usually darker green if they're growing on a land plant in the shade). However, a surprise awaited oceanographers at 60 meters. At that depth, they discovered an unusual “secondary, deeper chlorophyll max," something not seen many other places in the world.
  2. Oxygen -- This gas enters the ocean primarily at the surface, from the air and also from phytoplankton photosynthesis. Bacteria and other heterotrophs consume the O2 as they metabolize. Therefore, oxygen is expected to decrease with depth. At BiG RAPA's Station 1 oxygen not only fell; it fell all the way to near zero.

Dr. Angel White and the CTD
Dr. Angel White and the CTDCourtesy Eric Grabowski, C-MORE
"Sea It Live" in some BiG RAPA videos. Join Dr. Angel White from Oregon State University as she demonstrates the CTD rosette. Then join Dr. Repeta for his Chief Scientist Station 1 Update .
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*Educational resource = C-MORE Science Kit Ocean Conveyor Belt's Powerpoint, "Lesson 3: Using Data to Explore Ocean Processes "