Stories tagged hydrology

Earth's water: Most of it is saline and undrinkable. A lot of the fresh water is underground or locked in polar and glacial ice.
Earth's water: Most of it is saline and undrinkable. A lot of the fresh water is underground or locked in polar and glacial ice.Courtesy US Geological Survey
This cool graphic from the USGS Water Science School website gives you a really good idea of just how much water there is on Earth. Compared to the Earth itself, it doesn't look like much. The large blue globe represents the volume of all the water present on Earth, i.e. in the oceans, lakes, icecaps, atmosphere etc. The next size is the volume of the all fresh water - much of which is located underground. Don't overlook the very tiny blue globe positioned beneath the mid-sized water globe and just northwest of Florida in the graphic. That's how much fresh water is contained in all the lakes and rivers on Earth - the sources of life's drinking water. Feeling thirsty now?

Sep
17
2012

Prehistoric Antarctica shoreline: artist's conception of flora living during the Middle Miocene epoch.
Prehistoric Antarctica shoreline: artist's conception of flora living during the Middle Miocene epoch.Courtesy NASA / JPL-Caltech / Dr. Philip Bart, LSU
Recent investigations into microfossils show that Antarctica hasn’t been quite the icebox scientists have imagined it to be over the past 34 million years. Pollen and leaf wax samples from Miocene-aged sediments indicate the continent has experienced some periods of warming since the beginning of the most recent glacial period. The core samples studied came from ocean sediments collected near Antarctica, and particulates found in the samples indicate more rain fell on the ice-covered continent during the Middle Miocene epoch (15.5 – 20 million years ago) than previously thought, enough rain to spur the growth of forests of small, stunted trees.

Paleoclimatologist and organic geochemist Sarah Feakins of the University of Southern California and her colleagues analyzed core samples taken from between 144 and 1,100 meters beneath the ocean floor – levels dating back to the Middle Miocene. Spikes of concentrated amounts of pollens and leaf wax appeared in two periods – one about 16.4 million years ago, and another about 15.7 million years ago. The warm periods were relatively short, each lasting less than 30,000 years.

In a previous study, palynologist Sophie Warny of Louisiana State University had first described the pollen and leaf wax spikes found in the core samples, and she and Feakins eventually teamed up for the recent study. The team determined the particle spikes didn’t arise from the leaf wax and pollen blowing in from elsewhere but rather came from two species of trees that once lined the shores of Antarctica. The two species, podocarp conifer and southern beech wouldn’t have grown very tall – maybe knee-high – and neither spreads their pollen over wide areas. Had the pollens blown in from elsewhere - say South America or New Zealand - there were would have been more species in the mix.

Using a mass spectrometer, Feakins and NASA researchers analyzed the ratio of hydrogen to deuterium atoms in the wax molecules which indicated the temperature at the Antarctica location during the two warm periods was about 7 degrees Celsius during the summer. Today, summer temperatures in the same region are about –4 °C. The average global temperature at the time was about 3 °C higher than it is today. As the overall global temperature changes a relatively greater change in polar temperature isn't unexpected due to a process called polar amplification.

The data from Feakins and Warny’s study, which appeared in Nature Geoscience, adds to growing concerns over the sensitivity of Earth’s climatic and hydrological systems. At the moment, no trees line the shores of Antarctica, but current levels of carbon dioxide (393 parts per million) are not far off those thought to have existed during the Middle Miocene’s warm periods (400-600 parts per million) when forests did exist on the margins of the icy continent. This could indicate that even small changes in carbon dioxide levels can are capable of creating big changes in climate.

SOURCES
Earth magazine
Science on NBCnews.com

Feb
19
2012

The Blue Heron: the Large Lakes Observatory's research vessel is owned by the University of Minnesota-Duluth.
The Blue Heron: the Large Lakes Observatory's research vessel is owned by the University of Minnesota-Duluth.Courtesy Mark Ryan
Last October, I attended the Geological Society of America’s annual meeting held here in Minneapolis. The convention presented plenty of opportunities to hear the latest ideas in geology, paleontology, and planetary science but the highlight for me was being able to join a GSA field trip on Lake Superior aboard the research vessel, the Blue Heron.

Blue Heron interior: Mid-deck area includes monitoring station, right, and one of two dry labs, background left, serving as a snack table during our trip.
Blue Heron interior: Mid-deck area includes monitoring station, right, and one of two dry labs, background left, serving as a snack table during our trip.Courtesy Mark Ryan
The 86-foot vessel is owned by the University of Minnesota-Duluth (UMD) and operated by the Large Lakes Observatory (LLO), an organization created in 1994 for investigating the geochemical and geophysical properties of large lakes, and their global impact. To accomplish this research, the LLO required a worthy vessel for limnological research, and the Blue Heron was purchased just three years later.

The vessel docks at the Corps of Engineers Vessel Yard on Park Point (aka Minnesota Point), a natural sand bar separating Duluth’s harbor basin from Lake Superior. The ten-mile spit was created by the lake’s wave action on material deposited by the St. Louis river, and is supposedly the largest freshwater sand bar in the world. Field trip leaders Doug Ricketts, the marine superintendent at LLO, and Charlie Matsch, professor emeritus of geology at UMD, greeted arriving participants and divided us into two groups. While one group spent the morning on Lake Superior, the other visited geological highlights in the Duluth area with professor Matsch. In the afternoon the groups switched places.

I joined the morning shift on the lake with a dozen geologists made up of GSA attendees from Minnesota, Wisconsin, and City University of New York. Besides Doug Ricketts and the ship’s five crew members, regents professor Tom Johnson, and the director of the LLO, professor Steve Colman, were also on hand to help demonstrate and explain the Blue Heron’s research capabilities.Lakebound through the harbor: As we head toward Lake Superior, regents professor Tom Johnson, left, and  director of the LLO, professor Steve Colman, discuss the morning agenda with one of the field trip passengers. The yellow tow fish used for profiling the lake bottom sets on the deck in the background.
Lakebound through the harbor: As we head toward Lake Superior, regents professor Tom Johnson, left, and director of the LLO, professor Steve Colman, discuss the morning agenda with one of the field trip passengers. The yellow tow fish used for profiling the lake bottom sets on the deck in the background.Courtesy Mark Ryan

Safety first: Blue Heron chief mate, John Simenson, goes over some of the vessel's safety rules.
Safety first: Blue Heron chief mate, John Simenson, goes over some of the vessel's safety rules.Courtesy Mark Ryan
We shoved off right on schedule, heading across the harbor toward the Superior entrance on the Wisconsin end of the sand bar. The crew spent this time going over the ship’s safety rules - how to descend ladders, which alarms meant what, how to communicate with the bridge - that sort of thing. We then made a quick tour of the facilities. The Blue Heron is equipped with a wet lab on the open deck and two dry labs inside, and all sorts of data gathering equipment for geophysical, geochemical, and biological sampling. These include multibeam sonar for profiling the lake bottom and sub-bottom, several coring instruments for collecting sediment samples, and water samplers able to collect at various depth levels in the water column while also measuring such things as temperature, depth, pH levels, and conductivity. There’s gear for tracking lake currents, and plankton nets and a trawl for gathering biological data. Inside, both above and below deck, computers record, display and analyze the gathered data. Many of the off-ship instruments can be monitored and controlled on-board from computer consoles.

Out on the big lake: Lake Superior is the deepest and largest of the Great Lakes, and contains ten percent of the world's fresh surface water.
Out on the big lake: Lake Superior is the deepest and largest of the Great Lakes, and contains ten percent of the world's fresh surface water.Courtesy Mark Ryan
The R/V Blue Heron is outfitted to carry five crew members and six researchers and can stay on the lake, around the clock, for 21 days between port calls. It’s used mainly on Lake Superior, the largest and least studied of the Great Lakes. Shipboard amenities are sparse (there’s no television or DVD) but include eleven bunks, a full galley for food preparation, dining table, shower, and of course, the "head", or as you landlubbers like to call it, the toilet. Internet service is sometimes available when the vessel is near shore.

Yellow fish deployed: The EdgeTech CHIRP/sidescan sonar is submerged and towed behind the Blue Heron for gathering bottom data.
Yellow fish deployed: The EdgeTech CHIRP/sidescan sonar is submerged and towed behind the Blue Heron for gathering bottom data.Courtesy Mark Ryan
Upon entering Lake Superior, the crew set to work demonstrating some of the vessel’s science gear, which is pretty much the same kind of instrumentation used in oceanographic research. Just beyond the Superior entrance, the EchoTech CHIRP/sidescan sonar tow fish was lowered from the Blue Heron’s stern. This bright yellow instrument is towed underwater behind the vessel as it makes several passes over the lake bed, and able to gather hydrographic and bathymetric data. One function is to send out an intermittent, low frequency “chirp” pulse that can penetrate the sub-bottom and record changes in its geophysical properties. The sonar data is processed using on-deck computers.The first demonstration was a scan of the underwater channel of the Nemadji River, a Wisconsin tributary to the lake. The mouth of the Nemadji has been drowned by a process called post-glacial rebound or more scientifically, differential isostatic rebound. During the last ice age, a mile thick sheet of ice covered the region and placed enormous pressure on the earth’s crust, depressing it downward. As the glaciers retreated, that enormous weight was gradually removed, and the lake basin began to rebound (a process still going on today). But the northern and eastern ends of Lake Superior basin are rebounding at a faster rate, tilting the water southward and to the west and subsequently flooding those areas of the shoreline.

CHIRP/sidescan sonar monitors: Left display shows a sidescan view of the bottom.  Right monitor reveals CHIRP sub-bottom profile of drowned channel of the Nemadji river.
CHIRP/sidescan sonar monitors: Left display shows a sidescan view of the bottom. Right monitor reveals CHIRP sub-bottom profile of drowned channel of the Nemadji river.Courtesy Mark Ryan
As the submerged tow fish was doing its stuff, we all gathered at a couple workstations in the lower deck dry lab to watch as images appeared on the computer screens. In one, you could plainly see the distinct profile of the Nemadji’s drowned riverbanks. Lower deck dry lab: Marine superintendent Doug Ricketts explains the R/V Blue Heron's data gathering capabilities to field trip participants.
Lower deck dry lab: Marine superintendent Doug Ricketts explains the R/V Blue Heron's data gathering capabilities to field trip participants.Courtesy Mark Ryan
The other monitor displayed bathymetric information being picked up by the duel frequency sidescan sonar. Printouts of the lakebed topography, created from a mosaic of stitched-together scans, were laid out on a worktable with several charts and maps.

Yellow tow fish retrieval: Blue Heron marine technician Jason Agnich (left) and seaman Peter Norick haul in the EdgeTech sidescan sonar tow fish.
Yellow tow fish retrieval: Blue Heron marine technician Jason Agnich (left) and seaman Peter Norick haul in the EdgeTech sidescan sonar tow fish.Courtesy Mark Ryan
For the next demonstrations, the Blue Heron moved out several miles onto the big lake. We’d all been warned of the lake’s fickle weather, and told to bring proper attire, just in case. Having been raised in Duluth, I was well acquainted with Superior’s moodiness, especially in autumn, so I brought along rain gear, a jacket, and an extra sweatshirt, expecting the worst. But I was most comfortable in jeans and a t-shirt. Cloud cover was sporadic, and while the water temperature was only around 49 degrees, the air temperature hovered in the mid to upper 70s during the entire excursion. We couldn’t have hoped for a nicer day; a perfect Duluth day, as we used to call them.

While some of the group watched the crew prepare for the next presentation, others enjoyed lunch (sandwich, chips, fruit and a cookie) at the galley dining table. During my lunch break Tom Johnson told me the story of how the university came to own the research vessel. In her previous life, the Blue Heron was known as the Fairtry a commercial fishing trawler that fished the Grand Banks in the northwest Atlantic (like the Andrea Gail in The Perfect Storm). UMD purchased it in 1997 and Tom sailed it from Portland, Maine, through the St. Lawrence Seaway and across the Great Lakes to Duluth. Despite some minor engine problems at the start, he said it was a fantastic two-and-a-half week trip. Over the next winter, the Fairtry was converted into a limnological research vessel and re-christened the Blue Heron.

Water sampling carousel: GSA field trip participants listen as LLO's Doug Ricketts, center, goes over some of the geophysical and geochemical data gathered by the Blue Heron's water sampling carousel.
Water sampling carousel: GSA field trip participants listen as LLO's Doug Ricketts, center, goes over some of the geophysical and geochemical data gathered by the Blue Heron's water sampling carousel.Courtesy Mark Ryan
Meanwhile, out on the back deck, the crew was ready to launch the next instrument, a carousel of canisters called Niskin bottles used for sampling the water column. Topside control: Marine tech Jason monitors the submerged water sampling carousel, which can be controlled to collect water samples at different levels, as well as additional water quality data.
Topside control: Marine tech Jason monitors the submerged water sampling carousel, which can be controlled to collect water samples at different levels, as well as additional water quality data.Courtesy Mark Ryan
This device is lowered into the lake and controlled remotely from the deck, and can collect samples at various depths into any one of its dozen canisters. It can also measure temperature, conductivity, pH balance, transparency, dissolved oxygen levels and other tests. After deployment, marine technician, Jason Agnich, sat at a computer workstation just inside the hatch, and easily controlled the carousel with a joystick while monitoring its progress on a couple electronic displays.

Gravity corer: Marine technician Jason Agnich helps launch the gravity corer, retrieves the sample, and lays it out on the wet lab workbench for study.
Gravity corer: Marine technician Jason Agnich helps launch the gravity corer, retrieves the sample, and lays it out on the wet lab workbench for study.Courtesy Mark Ryan
We moved a little farther down lake where two coring instruments, a spider-framed multi-corer, and an arrow-like gravity corer were put into action. The first can collect several shallow core samples by lowering it by winch to the lakebed, while the latter is dropped like a giant dart deep into the sub-bottom sediment for one large core.

Sediment sample examination: Tom Johnson, left, and Steve Colman examine one of the sediment samples collected by the Blue Heron's multi-corer from the bottom of Lake Superior.
Sediment sample examination: Tom Johnson, left, and Steve Colman examine one of the sediment samples collected by the Blue Heron's multi-corer from the bottom of Lake Superior.Courtesy Mark Ryan
After each was raised back to the surface, the collected core samples were removed from their tubing and laid out on the wet lab table for study. We all huddled around the workbench as each core was cut open with a knife so participants could take a closer look. The sediment cores were composed of a densely packed fine-grained mucky silt as brown as milk chocolate, and appeared more appropriate for a scatological study than a geological one, to me anyway. But that didn’t stop some of us from taking home a small plastic bag of it as a souvenir.

View of the Blue Heron's wet lab: Lake bottom sediment samples are examined on the workbench.
View of the Blue Heron's wet lab: Lake bottom sediment samples are examined on the workbench.Courtesy Mark Ryan
View from the Blue Heron: As the research vessel heads back to port, autumn colors brighten up Duluth's distant hillside.
View from the Blue Heron: As the research vessel heads back to port, autumn colors brighten up Duluth's distant hillside.Courtesy Mark Ryan
As we made our way back toward the harbor, I stood at the starboard rail and took in the beautiful autumn colors lighting up the lake’s distant North Shore. We were three, maybe four miles offshore but I was able to pick out my old stomping grounds in Duluth’s east end. The old neighborhood – like much of the city - was built up on terraces formed by past shoreline configurations of prehistoric Lake Superior. Duluth’s Skyline Parkway, a boulevard that skirts the hilltop across the length of the city was built on an old gravel beach line of Glacial Lake Duluth when the water surface was nearly five hundred feet above its present level. The bridge over the mouth of the Lester River was just barely discernible from where I stood but it was easy to spot the large swath of dark pine forest that encompassed Lester Park and Amity creek (the western branch of Lester river) where my friends and I used to hang out. It’s also where Charlie Matsch would guide our group later in the afternoon. He brought us there to examine the Deeps, my favorite old swimming hole carved out of the massive basalt flows that extruded from what’s now the center of Lake Superior during the Mid-continental rifting event that took place nearly a billion years ago.

Harbor bound: The Blue Heron heads back to port through the Duluth canal.
Harbor bound: The Blue Heron heads back to port through the Duluth canal.Courtesy Mark Ryan
We returned to port through the Duluth entrance, and as we entered the canal captain Mike King announced our arrival with a blast of the Blue Heron’s air horn. Duluth’s landmark Aerial-Lift Bridge, already raised for our return entry, responded in kind with a shrill loud blast of its own. Tourists lining the pier called out and waved as we passed the old lighthouse and rolled toward the harbor. We all waved back and I have to say it was kind of a thrill, for me anyway, after having participated in the same ritual, oh probably a hundred times in the past but always from the pier not from a vessel.

Return to harbor: The Blue Heron heads back to port after passing under Duluth's landmark Aerial-Lift Bridge.
Return to harbor: The Blue Heron heads back to port after passing under Duluth's landmark Aerial-Lift Bridge.Courtesy Mark Ryan
The Blue Heron swung in through the harbor, and soon we were back at port where we started at the Corps of Engineers Vessel Yard. Charlie Matsch was there to greet us and take for the second leg of the field trip.

Charlie took us first up the hillside to the rocky knob near the landmark memorial Enger Tower where he showed us some interesting exposures of gabbro, an intrusive rock common to the geological formation known as the Duluth Complex. Much of the bluffs west of downtown Duluth are composed of this dark, course-grained mafic rock. Now, I admit I enjoy a geological outcrop as much as the next guy (especially when a real geologist is explaining it), but it was the sweeping view from the hilltop that drew my attention. The Blue Heron: cuts through Duluth's harbor for another excursion on Lake Superior.
The Blue Heron: cuts through Duluth's harbor for another excursion on Lake Superior.Courtesy Mark Ryan
The lake and harbor and much of the St. Louis river bay stretched out below us in an array of vivid blues contrasting with the bright reds and golds of autumn. On one side of the harbor, bridges, railroads, and structures of industry jutted out on Rice's Point toward Wisconsin, paralleled on the other side by the slender ribbon of Park Point. As I took in this grand vista, a small, barely discernible bluish blur of movement caught my eye. There, cutting through the harbor, the Blue Heron headed southward toward the Superior entrance for another run on the great lake.

More photos on Flickr
More about Blue Heron
Lake Superior facts
Lake Superior video

Minneapolis hosts 2011 GSA meeting: Six thousand geologists will descend upon Minnesota rocks this fall
Minneapolis hosts 2011 GSA meeting: Six thousand geologists will descend upon Minnesota rocks this fallCourtesy Mark Ryan
Next week the Geological Society of America is convening in Minneapolis, Minnesota for the GSA's 2011 Annual Meeting and Exposition. That means something like 6000 geologist, paleontologist, hydrologists, and other ologists from around the world will be in our area to share new ideas and hobnob with their fellow earth scientists. The four-day event, which is hosted by the Minnesota Geological Survey, runs from Sunday, October 9 through Wednesday, October 12 at the Minneapolis Convention Center, and will include special lectures, award ceremonies, poster sessions, an exhibit hall, and several hundred technical talks covering a full range of geology-related subjects. There will also be a silent auction, a photo exhibition, short courses (available to non-registrants), and a screening of the locally produced documentary, “Troubled Waters: A Mississippi River Story”. Field trips happening before, during, and after the official meeting dates will give visiting geologists an opportunity to take in some of the spectacular and diverse geology that Minnesota and the Upper Midwest has to offer, not to mention the fall colors. This year’s meeting is titled “Archean to Anthropocene: The Past is the Key to the Future”, and even if you can’t make it to Minneapolis, you can download a cool poster of the event here.

The GSA 2011 Annual Meeting and Exposition

The river level here at downtown St. Paul has been going down since the crest on 3/30 at 19.1'. We're holding now at about 17.3', and the National Weather Service predicts that the trend will bottom out tonight at around 17.2' before the river starts rising again. We're expecting a second crest at about 19.5' on the evening of 4/10, but that prediction doesn't take into account any rain we might get later on this week. Stay tuned...

The Advanced Hydrological Prediction Service has released a new short-term forecast for the Mississippi River at downtown St. Paul. (There's still too much uncertainty in the models to make a new crest prediction for the area.) We should see the river rise above flood stage by midday on Thursday, 3/24.

3-16-11 flood forecast
3-16-11 flood forecastCourtesy National Weather Service

Click on the image for a larger view.

Jun
22
2009

Tributary of Lake Erie
Tributary of Lake ErieCourtesy U.S. Federal Government

Among the water management savvy and those concerned with the state our water resources the riparian zone refers to an area where land meets a flowing body of water, like a river bank.

The SAHRA or the Sustainability of semi-Arid Hydrology and Riparian Areas is a research institute that works with such areas, especially in drier climates, like the southwestern United States where SAHRA is based out of. Scientists at SAHRA conduct research primarily in river basins, and their research is "stakeholder-relevant". This means that there are public and private agencies who are taking an interest in this research. These agencies help SAHRA inform communities and policy makers of the critical knowledge required to understand water management and the fragile state many of these riparian zones are in.

Research on water and riparian zones at SAHRA, the study of which is generally known as hydrology has helped shed light on the pressure caused by population growth and climate change and what it is doing to these fragile ecological zones. The main dangers of compromised riparian zones is drought or flood. SAHRA hopes that their research and their efforts will bring about legislative changes that will protect and sustain our water resources.