Friday, May 29, 2009

Diatoms in Long Island Sound

There are very few articles on the Internet about the role of Diatoms in the food chain and need for silica by Diatoms.
The Soundkeeper of Long Island Sound has written one such article on the research done by Dr Ellen Thomas of Yale University.
The Soundkeeper Mr Backer is also a State Representative of Connecticut.

Attack of the Jellifish--Is nitrogen pollution changing the food chain in the Long Island Sound?

By: Terry Backer and Julia Hyman

Ellen Thomas, PhD, a professor at Yale and Wesleyan University, released findings showing that nitrogen pollution, and perhaps warming waters, may have changed the basis of the food chain in the Long Island Sound. Her research shows that a key shift in populations of microscopic algae has been occurring over the last several decades. This fundamental shift in the Sound’s menu of who eats what is likely to cause many familiar species’ populations to decrease.

At the base of the Sound’s food chain are diatoms--single celled organisms that are found in fresh and salt water. Foraminifera, or forams, are also single celled organisms which adopt dazzling and intricate shapes with many looking like exotic microscopic seashells. Until recently the most common foram in the Sound was Elphidium excavatum, which eats diatoms. For 10,000 years diatoms were the most important microscopic algae suited to the Sound’s water temperatures and nutrient levels (including nitrogen). The marine biota that we know thrived, either directly or indirectly, on these organisms.

Historically, and up until the 1990s, E. excavatum was the dominate species of foram in the Sound. E. excavatum as well as copepods (small crustaceans eaten by many fish), rely on a diet of diatoms to maintain their population. Diatoms need not only nitrogen to grow (like other plants), but also need silica which they use to form a thin exoskeleton, just like grass contains some silica. Humans add a lot of nitrogen to the Sound from polluted runoff and sewage treatment plants, but no silica, so that ratio (N/Si) becomes unfit for diatoms to thrive so that now, other microscopic algae are out-competing diatoms. This is happening in parts of the Sound right now, especially in western Long Island Sound.

Excessive nitrogen from sewage treatment plants, polluted runoff from storm water and other sources has pushed the nitrogen-silica ratio out of whack, and thus lowered the population of diatoms available for E. excavatum. Other micro-organisms, like cyanobacteria, commonly known as blue-green algae, do not need silica to survive, and in fact many species of cyanobacteria thrive in high nitrogen environments, but these organisms are not suitable as food for many animals at the bottom of the food chain. Cyanobacteria are not a good food source for most organisms, the reason being that they’re just too small to eat.

As diatom availability drops so do populations of its consumers, eventually leaving a gap to be filled. This is where another species of foram steps up:Ammonia beccarii, which has a much wider food range. It eats diatoms andother algae. This wider diet gives A. beccarii a great advantage on E. excavatum. A. beccarii has always existed in the Sound, but in lower numbers compared to E, however, it is now becoming the dominant species in western Long Island Sound.


We do. The decreasing population of E. excavatum signifies a fundamental shift in the Sound’s food chain. Our good old, traditional E. excavatum is slipping to second place in favor of A. beccarii, the species more tolerant of excessive nitrogen levels. Small diatom-feeding organisms form the base of a food chain that begins with diatoms and ends with animals we like to eat like lobster, scallops, and many fish.

Attack of the Killer Jellyfish?

Here’s the rub: Jellyfish are one of the few organisms that have no problem eating blue green algae. Jellies can feed on smaller particles in the water. This shift in the food chain could mean jellyfish become dominant over the seafood we crave. Couple this with pH changes and warming waters and we have the stuff of a B-grade movie. Jellyfish don’t appear on many menus here…yet. They can be poisonous and, as many know, uncomfortable to swim with, to say the least. Also, jellies feed on the larval stage of many of the animals we eat, which further causes their population to drop.

These tiny forams are sending a message to us about our pollution in the Sound. Are we listening?



Thursday, May 28, 2009

Diatoms in the food chain

Flood of ‘08 served up feast for fish
May 28, 2009

By Jennifer Yauck
One year ago this month, a series of severe storms moving across the Midwest dropped nearly a foot of rain on the Milwaukee area in just 10 days. The deluge caused widespread flooding that damaged homes and businesses, washed out roads, closed the airport, and belched plumes of sediment, debris, and sewage into Lake Michigan.
But the flood may also have delivered food to some of Lake Michigan’s fish when they needed it most.
Among the many things the area’s swollen rivers carried out to Lake Michigan during and after the storms was a mix of the rivers’ microscopic algae (phytoplankton), including diatoms, said Carmen Aguilar, a scientist at the Great Lakes WATER Institute. Diatoms are one of the largest forms of phytoplankton and the only form having glass-like cell walls made of silica. Diatoms also are packed with lipids, making them a nutritious meal for newly hatched fish and the tiny aquatic animals that newly hatched fish also eat.
“Compared to other phytoplankton, diatoms are like juicy steaks,” said Aguilar, who has been studying Lake Michigan’s diatoms and other phytoplankton for over a decade.
According to Aguilar, diatoms historically accounted for most of the phytoplankton found in the sun-fueled spring blooms in the Milwaukee-area waters of Lake Michigan. Those blooms typically begin in shallow, nearshore waters in late April and May, and spread to offshore waters in May and June, where they eventually sink. In the past, the diatom-rich blooms nourished the tiny animals that in turn nourished the babies of spring-spawning fish such as perch, which hatch around mid-June.
This satellite image of Lake Michigan was taken July 10, 2008, one month after the storms. The colors reflect the concentration of chlorophyll, a pigment found in phytoplankton, in the lake’s surface waters. Higher concentrations of chlorophyll (red) indicate a higher abundance of phytoplankton (most of which were diatoms in this case), while lower concentrations (blue) indicate lower abundance. The highest abundances of phytoplankton are seen at the mouths of major rivers around the lake (1-Milwaukee River drainage; 2-Two Rivers; 3-Sturgeon Canal; 4-Northern Green Bay/Death’s Door; 5-Muskegon Lake drainage; 6-Portage Lake/Frankfort drainage area). ~courtesy William Balch, Bigelow Laboratory for Ocean Science
But the makeup of the blooms began changing around 2003, according to Aguilar. That’s when the invasive quagga mussel-a voracious filter feeder with a fondness for diatoms-became well established in Lake Michigan. As a result of the quaggas’ feeding habits, the diatom population has declined significantly in recent years in the areas that Aguilar studies-within about 40 miles of Milwaukee-if not beyond.
The diatom decline, in turn, has left each year’s batch of newly hatched perch and other baby fish struggling to survive on a less nutritious diet, said Aguilar. As a result, these fish have a smaller chance of growing into adults and producing new young to sustain their populations. For an already struggling fish like perch, whose population in the Wisconsin waters of Lake Michigan dropped from a high of 23.6 million to a low of 264,000 since the early 1990s, that’s not good news.
But last year’s baby fish may have caught a break in the form of the June flood, which Aguilar said forced massive amounts of water-and diatoms-through the area’s rivers and out into Lake Michigan in a giant plume. She and her colleagues investigated the plume during a research cruise aboard the WATER Institute’s Neeskay June 10, 2008, just two days after the heaviest rains. What they found surprised them. “Outside the plume it was the same old, same old, but inside the plume there were diatoms everywhere,” said Aguilar. “Everybody was like, ‘Wow!’”
What’s more, the diatoms flourished unusually late into the summer-mid-July-and drifted unusually far-to the middle of the lake-as the plume expanded. Based on analysis of water samples for silica, the material found in diatom cell walls, and chlorophyll, a green pigment found in diatoms and other phytoplankton, Aguilar estimates some areas of the lake had two to three times more diatoms in 2008 than in 2007.
Most importantly for perch, all those diatoms entered the food web right around hatching time. Aguilar and fellow scientist Russell Cuhel suggest that such coincidences can dramatically improve baby perch survival, and may explain why some years have a “baby boom” of perch larvae. Such booms have occurred in the past during so-called El NiƱo years, when storms increased the lake’s turbulence and stimulated diatom growth in May and June, they said. And anecdotal reports suggest that the alewife, another Lake Michigan prey fish that also would have benefited from the 2008 influx of diatoms, reproduced in much higher numbers last year compared to other recent years.
So far, 2008 hasn’t stood out as a boom year, based on initial assessments by the Wisconsin Department of Natural Resources. But booms often do not become evident until several years later, when fish are bigger and more easily captured during assessments. Such was the case for perch born in 1998, 2002, and 2003.
Should 2008 eventually prove to be a strong year, it would provide a small boost to the diminished perch population, said Aguilar-but it would still only be a small step toward significant recovery.
Jennifer Yauck is a science writer at the Great Lakes WATER Institute. GLWI ( is the largest academic freshwater research facility on the Great Lakes.

The Milwaukee River drains an area of almost 700 square miles before converging with the Menomonee and Kinnickinnic Rivers in downtown Milwaukee. After a series of severe rainstorms between June 5 and 14, 2008, water flowed through the Milwaukee River at a rate as high as 60,000 gallons per second, according to U.S. Geological Survey readings taken at Estabrook Park. That’s 32 times the normal June flow rate of 1,870 gallons per second!

Saturday, May 23, 2009

NOAA Eutrophication Update

"Factors influencing eutrophication (nitrogen load and susceptibility) were high for the majority of assessed systems.

"The majority of estuaries assessed had overall eutrophic conditions rated as moderate to high.

"If only assessed systems are considered, conditions have improved in 13 estuaries, worsened in 13, and remained the same in 32 systems...."

Wednesday, May 20, 2009

Diatom Algae bloom

Algae in Atlantic could move southward from Brevard County
By Tyler Treadway

TREASURE COAST — It looks bad, it smells bad, and it may be heading our way.

The algae floating in the Atlantic off Brevard, Flagler and Volusia counties isn't dangerous; but it deserves monitoring, say scientists.

"It's not red tide," said Cindy Heil, senior research scientist and leader of the red tide group at the Fish and Wildlife Research Institute in St. Petersburg, "that's the main thing. It's not toxic and it's not harmful."

But Brian LaPointe, a research professor at Harbor Branch Oceanographic Institute at Florida Atlantic University in Fort Pierce, said the current algae bloom could be a precursor of a red tide bloom.

Red tide can cause eye, nose and throat irritations similar to a cold. People with severe or chronic respiratory conditions are cautioned to avoid red tide areas. When red tide is present in large concentrations, it can produce toxins that kill fish. Shellfish from areas with red tide shouldn't be eaten.

"You can get what we call a series succession," said LaPointe, who's been studying algae blooms for more than 25 years. "First you have a diatom bloom like the one we're seeing now, then you see other species becoming dominant. It's not unusual for a red tide to follow a diatom bloom."

The clouds have discolored water since late April and, have been identified as the diatom algae, Thalassiosira.

"It's a single-cell plant that's the basis of the food chain," Heil said. "What's causing the problem is that there's just so many of them."

Heil said the algae isn't formed in a single mass but is "lots of little masses" that can be as small as "tens of yards across. But I've also seen them a couple of miles long."

The bloom potentially could kill sea life if it sucks up more oxygen than it produces through photosynthesis, Heil said, "but there haven't been any reports of impacts due to a net loss of oxygen."

In extremely rare instances, she added, the algae also can kill fish and shellfish by clogging their gills.

LaPointe said the recent rains along the Treasure Coast and Space Coast to the north could exacerbate the situation by flushing nutrients into coastal waters.

"Historically, red tides follow rainfall and discharges," LaPointe said, "and since we've had a drought for a while, that first flush of fresh water will be carrying a lot of nutrients."

It's possible, Heil said, that the algae blooms could travel south to the Treasure Coast.

The Treasure Coast's last outbreak of red tide, in December 2007, moved south from Volusia and Brevard counties; and the current diatom algae bloom could do the same.

"Although the Gulfstream moves south to north," Heil said, "coastal currents tend to go north to south. It gets moved around by tides and currents. It's already moved around quite a bit."

Saturday, May 16, 2009

Beneficial freshwater algae

Beneficial freshwater algae

Algae are a diverse group of organisms that occur in various shapes and sizes and have different ecological roles. Thousands of species of algae occur world-wide in both fresh and marine waters. Many species of freshwater algae float in the water, but others are attached to submerged rocks or aquatic plants. Most freshwater species are inconspicuous and do not create problems for humans. There are only a dozen or so, so-called "bad actors" that are considered problem-causing algae.

Algae typically serve as an important and welcome part of a lake or pond ecosystem. They form the base of the food chain and are a vital component of lakes. Algae provide a source of food, energy, and shelter for zooplankton (tiny water animals), fish, and other lake organisms. They can play a crucial role in the ability of a ecosystem to absorb nutrients and heavy metals.

The most commonly encountered groups of freshwater algae are green algae, diatoms, and blue-green algae (more correctly known as cyanobacteria). A large and varied group called green algae are the likely ancestors of terrestrial plants. Green algae contain bright, grass-green pigments, and are more abundant than all the other groups. The cells of green algae may occur singly, as spherical colonies, or as filaments. Sometimes filamentous green algae can create problems when it grows in "cotton candy" type clouds in the water. Generally most green algae are highly palatable and a good food source for zooplankton.

Diatoms appear as yellow-green or yellow-brown algae that occur singly or more rarely in colonies. The cell wall comprises two separate valves or shells formed of silica (a major component of glass). The two shells fit together as do the two halves of a petri dish. Because of the silica valves, diatoms often occur in beautiful shapes when viewed under the microscope. Diatoms reproduce through cellular division and also sexually. Each time an existing diatom divides, the silica valves get smaller. Over time, individual cells of a diatom population become smaller and smaller. Luckily for diatoms, their sexually produced offspring are able to secrete entirely new cell walls. World-wide, diatoms provide a major food resource for zooplankton and also produce atmospheric oxygen ( Some marine diatoms can produce a toxin called domoic acid. Domoic acid can accumulate in shellfish and poison humans Freshwater diatoms do not produce this toxin. In Washington, diatoms are often the first algae to bloom in early spring. See photographs of diatoms at:

Blue-green algae (cyanobacteria) contain green, blue, and often red pigments. Blue-greens create problems when their excessive growth produces algae blooms, and few people view them as beneficial organisms in a lake environment. Blue-green algae are discussed elsewhere on Ecology's website.

Other types of algae found in lakes include: Euglenoids, dinoflagullates, brown algae, stoneworts/brittleworts, and desmids. This list is not inclusive of all the kinds of algae that are found in freshwater. Most freshwater algae do not cause problems in lakes. Because they provide a food source for zooplankton, they tend to be rapidly consumed and rarely cause the prolonged blooms that can occur with blue-green algae.

Wednesday, May 13, 2009

Chesapeake Bay Program - President Obama -more studies and reports

Federal Action on the Bay
President Obama wades into the Chesapeake.

Wednesday, May 13, 2009

AS EXPECTED, the meeting of the Chesapeake Executive Council yesterday did not come up with any magical prescriptions for the deteriorating health of the bay. But it was accompanied by something new, and potentially valuable: an executive order from the president that commits the federal government to a more direct and assertive role in cleaning up the nation's largest estuary.

The Chesapeake Bay Protection and Restoration order establishes a Federal Leadership Committee to oversee and coordinate all state and federal activities to clean the waterway. Lisa P. Jackson, administrator of the Environmental Protection Agency, will lead the outfit. She will consult with Cabinet secretaries and state authorities to devise a master plan for the bay's revival. The order also commands federal agencies with land in the watershed to implement land management practices that will benefit the health of the bay. Authority under the Clean Water Act is Ms. Jackson's hammer to ensure that the goals President Obama sets out are met.

On the one hand, you could look at yesterday's meeting with a certain weariness. Officials from the federal government, along with the six states and the District of Columbia that share the bay's 64,000-square-mile watershed, promised -- surprise! -- more studies and reports. A draft report on the key challenges to protecting and restoring the bay is due within 120 days. Final reports from the Agriculture, Commerce, Defense and Interior departments are due within 180 days. A draft of the overall strategy for public comment is also due within 180 days, with the final document submitted within one year. As if nodding to the work already being done by states, including Maryland, Virginia and the District, Mr. Obama encourages them to keep going before the final strategy has been adopted. But there's been so much study of what ails the waterway that these deadlines surely could be met earlier.

On the other hand, Mr. Obama's leadership could prove to be a big deal. Not since 1984 has a president shown such concern for the sorry state of the Chesapeake Bay. That's when President Ronald Reagan mentioned it in his State of the Union address and put a dollop of money into the budget to fund what would become the Chesapeake Bay Program of the EPA. But despite that program and unending promises, conditions in the bay have only declined in the two and a half decades since. Now Mr. Obama has put the full weight of the White House behind cleaning up the historic waterway. If the effort fails this time, he'll own it.

Fish Kills in North Dakota

"Significant" Winter Fish Kills Reported in Area Lakes
By North Dakota Game and Fish Department
May 11, 2009, 10:01

BISMARCK - A long winter caused a prolonged ice pack, and coupled with near-record snowfall throughout much of the state, resulted in conditions that made it difficult for fish in some lakes to receive enough oxygen to survive.

Scott Gangl, fisheries management section leader for the North Dakota Game and Fish Department, said 37 winterkills have been confirmed so far. The majority were in the western half of the state, where lake water levels were very low going into winter.

“The winter of 2008-09 was on par with the epic winter of 1996-97, when 46 lakes experienced winterkill,” Gangl said. “Similar to that winter, all is not lost.”

Fisheries personnel have already started restocking efforts on some lakes that experienced winterkill. “We are stocking with hatchery raised fish, or fish transported from another lake with an abundance of the preferred species,” Gangl said. “These fish may take a while to grow to catchable size, but in two to three years there should be populations of fish for anglers to catch.”

The severity of a die-off may vary by lake, but usually there are some fish left in the lake. “Most of the lakes that experienced winterkill are prone to die-offs,” Gangl said. “So while there was some disappointment in losing good fisheries, there weren’t many surprises.”

Fisheries biologists are in the process of sampling suspected winterkill lakes to document the severity of the die-offs. Biologists use three levels to describe the severity of a fish kill: total, where all fish died; significant, where the game fish population is greatly reduced; or partial, where dead fish were observed but game fish are still present.

Confirmed lakes with winterkill are listed by fisheries management districts. Anglers can contact the local Game and Fish Department fisheries supervisor to get more information on the status of these lakes, or to report fish kills that may not be on the list.

North Central – Jason Lee, Riverdale, 654-7475

·North Carlson Lake, Ward County – significant

·Coal Mine Lake, Sheridan County – significant

·Cottonwood Lake, McHenry County – significant

·Crooked Lake, McLean County – significant

·South Carlson Lake, Ward County – partial

Northeast – Randy Hiltner, Devils Lake, 662-3617

·Harvey Dam, Wells County – significant

·Island Lake, Rolette County – significant

·School Section Lake, Rolette County – significant

·Sykeston Dam, Wells County - significant

Northwest – Fred Ryckman, Williston, 774-4320

·McLeod (Ray) Reservoir, Williams County – significant

·Nelson-Landers Pond, Ward County – total

·Skjermo Lake, Divide County – significant

·Stanley Reservoir, Mountrail County – total

·Tioga Dam, Williams County - total

South Central – Paul Bailey, Bismarck, 328-6688

·Beaver Lake, Logan County – significant

·Braddock Dam, Emmons County – significant

·Cherry Lake, Kidder County – significant

·Dollinger-Schnabel Lake, McIntosh County – significant

·Fresh Lake, Kidder County – significant

·Lake No. 5, Kidder County - significant

Southeast – Gene Van Eeckhout, Jamestown, 253-6480

·Crystal Springs, Stutsman County – partial

·Bisek Slough, Richland County – significant

·Boom (Marion) Lake, LaMoure County – significant

Southwest – Jeff Hendrickson, Dickinson, 227-7431

·BarZ Dam, Dunn County – total

·Cedar Lake, Slope County – significant

·Danzig Dam, Morton County – significant

·Dickinson Reservoir (Patterson Lake), Stark County – significant

·Gascoyne Lake, Bowman County – significant

·Holocek Dam, Bowman County – total

·Mirror Lake, Adams County – significant

·Odland Dam, Golden Valley County - partial

In addition, East Spring Lake Pond in Williams County, Watford City Park Pond in McKenzie County, Beach City Pond in Golden Valley County, Belfield Pond and Dickinson Dike in Stark County, and Gaebe Pond in Morton County suffered fish kills this winter. However, those ponds are stocked with catchable size fish, typically consisting of trout, sunfish or catfish. Anglers visiting these ponds may notice some dead fish, but there are recently stocked fish to catch.

Fish and Plants

‘Farm in a Barrel’: raise fish and grow your own organic vegetables

May 12th, 2009 ·
By Chris Reinolds
Green Right Now

Talk about eating locally.

It doesn’t get much more local than your own backyard.

A Georgia company is selling ‘Farm in a Barrel.’ It’s a self-contained eco-system that allows homeowners to raise organic fish and vegetables at the same time. The method, called aquaponics, combines aquaculture (fish farming) and hydroponics (growing plants in a soil-less system.) The fish produce the nutrients to feed the plants, while the plants and bacteria clean the water for the fish.

Earth Solutions‘ smallest system is about $200. Fish, such as tilapia, catfish, and bass live in the detached bottom half of the barrel, while basil, lettuce and strawberries grow in the top half. Tilapia is a hardy fish that produces a lot of ammonia - don’t ask - for the plants to grow.

Larger systems cost upwards of $2,500, but also produce a lot more organically grown fish and food.

A beginner’s kit comes with one-inch long fingerlings. It takes about seven months for the fish to reach maturity - or plate size. At that point it’s up to you whether to eat one a week or have all the neighbors over for an old-fashioned fish fry.

For the squeamish, Earth Solutions owner David Epstein recommends putting the fish on ice to kill them.

“They just fall asleep,”‘ said Epstein, who is also a medical doctor. “You can cook them whole. Leave the head on, slice the belly and take the guts out.”

To keep the fish year round, use a greenhouse or a heater to keep the fish comfortable. If you don’t want to eat the fish, try hardy goldfish.

Epstein started building the units as a passion last summer and it’s taken off. The smaller sizes - about 2 by 5 foot in diameter - are used for educational needs and folks who want to start small.

“We do a lot of these in people’s backyards for a single family,” he said. The family size systems can support a 300-square-foot garden. Larger systems (see picture, right) allow you to grow more variety such tomatoes, eggplants and cucumbers.

The water loving plants go from seedling to bountiful plant in six to eight weeks. That’s about 125 plants in each 3-by-8 foot bed. Aquaponics enthusiasts say the system uses 90 percent less water than traditional gardens. What you save in water costs, may show up in your electric bill to run the pump and aerator - about $25 monthly. But plants grown in these systems are more productive overall.

You’ll also lower your carbon footprint by cutting down on frequent trips to the grocery store.

In addition to the Earth Solutions sustainable gardens page, see Backyard Yard Aquaponics for more. Also see this YouTube video on aquaponics.

Earth Solutions also is exhibiting an aquaponics system at the Oakhurst Community Garden in Decatur, Ga., in the Atlanta metro area.

Diatom Algae in River Kenai, VA

May 13, 2009...6:55 am
Science of the Seasons: Tiny particles have big role in stream ecology.

By Dr. David Wartinbee, for the Redoubt Reporter

Have you ever stepped into a stream and had your foot slip on a flat rock? Maybe you really slipped, lost your balance and took a bath you hadn’t planned? If you spend enough time around streams, you probably will have this experience, or perhaps your own special version of embarrassment. The cause of these slippery surfaces is a bunch of microscopic, photosynthetic organisms called diatoms.

Diatoms are made of two paired frustules — their external cell wall — or “tests” of silicon dioxide (also known as glass) that fit together much like the petri dishes we use in microbiology. These miniscule frustules may only be 20 to 200 microns in length (one micron equals one millionth of a meter), and often have intricate, consistent openings or striations on the surface. When they reproduce, one new cell gets the outer frustule and the other cell gets the inner frustule. Each new cell then replaces the specific-size frustule they are missing by extracting dissolved silicon from the water. This way, the diatom cell size stays the same.

These are minute photo-synthetic organisms. They capture energy from light and combine it with carbon dioxide and hydrogen from water to form energy-rich carbohydrates or sugars. As part of this photosynthetic chemical reaction, diatoms split water to get the needed hydrogen, and they then release oxygen into the water. The carbohydrates produced by diatoms make them an important food source for many aquatic invertebrates.

A large number of diatoms are found floating near the surface of ponds, lakes and oceans so they can absorb the light they need for photosynthesis. Other members of this large, diverse group of algae will attach themselves to substrate surfaces, like rocks or stream and lakeside vegetation. Sometimes you can see a fuzzylike layer on the surface of aquatic vegetation, which is most likely a mass of diatoms. Those attaching to various substrates use gelatinous layers and stalks to hold themselves in place. It is these gelatinous coverings that make rocks so slippery in the stream.

Diatoms are an integral part of any stream or lake food web. They are a favored food item for a great many aquatic insects and other aquatic invertebrates. Once the cell components are digested, the silicon frustules are eliminated. The diatoms continue to reproduce on stream rocks as insects continually graze on them. One can think of it kind of like a miniature pasture with insects taking the place of grazing horses and cows.

In various experiments, stream ecologists have found that if the insects are prevented from feeding on the diatoms, the community becomes thick and overgrown, kind of what the pasture looks like when we fence out cattle.

In northern latitude stream systems, like those streams above the Brooks Range, diatoms can be the major source of energy for the entire stream. This occurs because there is very little riparian vegetation and only limited amounts of in-stream vegetation available as possible invertebrate food.

The frustules that pass through the insect gut will mostly remain intact and may build up in the bottom sediments of streams, lakes or ponds. In graduate courses in stream ecology that I used to teach, we would extract the guts of a variety of insects and examine the contents with a scanning electron microscope. We would photograph the diatom contents and could then compare the preferred diets of different aquatic insects.

By looking at the bottom sediments of a pond or lake, ecologists can determine which diatoms were living there in the past.

By taking layered core samples of lake bottoms, scientists can determine changes in the populations of diatoms over a time period. Those changes in diatom communities can then be used to infer climatic and community conditions in the past.

In some areas of the oceans, or areas of ancient oceans, there are so many frustules in the sediments that they are mined for industrial uses. Because of their very small size and the porosity of the material, the silicon frustules can be used as micro-filters. Many swimming pool filters or home fish-tank filters use “diatomaceous earth” as the primary material the water is passed through.

Diatomaceous earth has also been used as an insecticide because the tiny fragments of frustules (remember, they are made of glass) stick to the insect and abrade the exoskeleton as the insect moves. Eventually, the exoskeleton springs a leak, the insect dehydrates and dies.

While diminutive in size, diatoms are key players in virtually every aquatic environment. They can be a major producer of oxygen, a big-time consumer of carbon dioxide, a critical food source for many invertebrates and the reason many of us have lost our footing while wading in a stream.

David Wartinbee, Ph.D, J.D., is a biology professor at Kenai Peninsula College’s Kenai River Campus. He is writing a series of columns on the ecology of the Kenai River watershed.

Wednesday, May 6, 2009

Million $ house, 100000 $ lawn, no water ...

'New Era' in Water Means Brown Lawns

Mayor Jerry Sanders' [of San Diego] latest water conservation proposal calls for designated lawn watering days throughout the city.

Monday, May 4, 2009 | Coming this summer to an inland neighborhood near you: Brown lawns.

Mayor Jerry Sanders unveiled a plan Monday to designate specific lawn watering days for all residents and businesses, a step one horticulture expert said would "absolutely" cause brown and dying lawns across the city this summer. The risk would be higher farther inland.

Sanders' plan would allow residents in odd-numbered houses to water their lawns on Sundays, Tuesdays and Wednesdays. Even-numbered houses would be permitted to irrigate Mondays, Wednesdays and Saturdays. Businesses, condos, apartments and homeowners associations would be allowed to water on Mondays, Wednesdays and Fridays.

"Today, we're poised at the beginning of a new era in San Diego's water history," Sanders said.

The plan heads to City Council for consideration and possible approval Tuesday afternoon. It comes as the city faces mandatory water cuts from its suppliers for the first time since the early 1990s.

If approved, regulations would begin June 1 permitting residents to water for 10 minutes on each specified day and only between the hours of 6 p.m. and 10 a.m., when less water is lost to evaporation.
Related Links

That won't be enough to keep many lawns green, said Don Schultz, an instructor in the ornamental horticulture department at Cuyamaca College. Schultz said on average, lawns in San Diego need about 20 minutes of water three times a week to stay green. That depends on where residents live, the efficiency of their sprinklers and their lawn's soil type.

"To apply half of what I'd consider the optimal water probably wouldn't keep it green," Schultz said.

The city of San Diego's lawn-watering calculator recommends watering grass during the summer between 35-40 minutes weekly along the coast and between 48-50 minutes farther inland, where the climate is drier and warmer.

The 10-minute, three-times-weekly baseline was recommended by the San Diego County Water Authority to water districts across the county. John Liarakos, an authority spokesman, said three 10-minute cycles weekly should be enough to keep lawns green.

"If it's done properly, if they're doing it after dark, before early morning, it should be adequate," Liarakos said.

Under the proposal, the city's Water Department would spend $750,000 to hire 10 code enforcement staff -- water cops -- to investigate complaints of waste and ensure compliance. It will rely on neighbors to report waste. Alex Ruiz, the department's assistant director, said the city would take a "progressive approach" to enforcement. While it could fine residents between $100 and $1,000 for violating the lawn-watering rules, the city will give residents at least two warnings before fining them.

Residents with efficient irrigation systems, such as drip irrigation, would be exempt. So would golf courses' greens and tees.

The county water authority is restricting deliveries to San Diego and other local cities by 8 percent, as it copes with dry weather, low reservoir levels and Northern California pumping restrictions. If the city fails to meet that target -- residents would need to improve on the 5 percent they voluntarily conserved last year -- it will face financial penalties. The city has no means to pass those financial penalties on to its customers if they use too much.

City Councilwoman Donna Frye, who joined Sanders at a Monday press conference, said she believed city residents would respond. "I have a lot of faith in the public," she said. "I believe they'll actually take this to heart."

Sanders had pushed earlier this year for a plan that would've established water budgets for each household based on their historical consumption -- a plan criticized for its lack of fairness.

The city has turned away from that plan as the year's water-supply picture has improved. Sanders said the city now has time to evaluate other options.

"This gives us an opportunity to review what we did, what's out there," Sanders said. "This is a great time to look at all the alternatives as we move forward."

The city's current plan has no guarantee of success. The state Department of Water Resources warned in a 2008 report that designated lawn-watering days don't always work. "Some residents water on the designated days regardless of whether the landscape needs it," the report states. "Others over irrigate their landscapes in the hope the irrigation will last longer. This overuse cannot be controlled by patrols."

The report also cautions that confining lawn watering to nighttime hours, when residents are sleeping, can allow sprinkler malfunctions to go unnoticed.

San Diego's Water Department will report to a City Council committee monthly on the success of lawn-watering days. Ruiz said the city should know how successful the effort has been by the fall. Water use is heaviest during the summer.

Please contact Rob Davis directly at with your thoughts, ideas, personal stories or tips. Or set the tone of the debate with a letter to the editor.

Tuesday, May 5, 2009

Diatom Algae's contribution to global photosynthesis

"Diatoms may just seem like they are just part of the plankton that feed that fish and animals. But they are huge contributor to the oxygen that is put in to the water and the carbon. It is estimated that 40%, 50 billion to 55 billion tons, of all organic carbon fixation on the planet (transformation of carbon dioxide and water into sugars, using light energy) is carried out by diatoms. This is comparable to all of the world's tropical rainforests."

Monday, May 4, 2009

Declining fish population responsible for Global Warming?

Eating Fish Kills... Saving our Oceans.
Share: by Paschen | January 21, 2009 at 05:13 am

By, Uwe Paschen.

There are today about 812 to 2050 Million tons of Fish left in the Oceans compared to 7,000 to 15,000 million tons estimated only two century ago.

The remaining Fish stock produces 110 million Ton of Calcium carbonate Annually. Would we repopulate the Ocean with Fish to levels as two centuries ago. We would then increase the production of Calcium Carbonates by a factor of 10 to 14. Giving us an additional 1000 to 1400 million Ton of Calcium Carbonates. This additional Calcium Carbonate would raise the PH level of the Ocean, save the Coral Reefs and increase the CO2 absorption rate as well as help cool down the over all Oceanic Temperature and increase as well as accelerate the filtration of toxins and other polluted.