Diatoms are the grasses of the oceans with a bountiful supply of food for a host of creatures

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Have you ever wondered who plays the role of grass in the oceans? Try diatoms, delicate unicellular organisms that have a yellow-brown chloroplast that enables them to photosynthesize.

Illustration courtesy of Wipiter / Diatoms form a major group of algae and a major food source in the ocean waters.


Flying eastward from Los Angeles to Washington D.C, urban scenes soon turn into the spare and spectacular brown vistas of the western United States. Aerial views of the Mojave Desert and parts of the Grand Canyon are well worth window seats.

A few hours further into an eastbound flight and the scenery transforms again into the plush greenness of the Midwestern, then New England states.

Whether lush in the east or spare in the west, terrestrial vegetation such as grasses and trees play the key role of converting sunlight and nutrients into food that sustains almost all other life on earth.

What sustains life in the oceans? Is there grass in the oceans? Let’s see. You could say Diatoms are.

Their cell walls are made of silica almost like a glass house. The construction of the cell wall, termed the ‘frustule’, consists of two valves that fit into each other like a small pill box.

The color of the chloroplast is yellow-brown instead of the green that we know of from other creatures that use light as a source for energy. There are two different types of diatoms, one, the pennates which are pen-shaped. At the end of the winter they are most numerous in fresh water.

They will cover surfaces of aquatic plants or poles and wooden borders of ponds. If you like to study them you can scrape off the brown growth with a flat piece of plastic. You can also use a sponge.

For the free living plankton species a special fine mesh plankton net is very useful. Many species of diatoms stay connected after the cells divide. They can form colonies and long chains. Sometimes only the tips are connected and others form a zig-zag pattern.

The cells of diatoms are ideal subjects for study under the microscope. They show complex patterns of very fine punctures. The best way to make the beautiful structures of the frustule visible is to remove the content from the cell. Using hydrogen peroxide can accomplish this removal. But it is also possible to find empty frustules of dead diatoms.

The extremely fine pores in the frustule of certain species of diatoms are used to test the resolving power of a microscope's lens.

Diatoms are found in almost every aquatic environment including fresh and marine waters, soils, in fact almost anywhere moist. They are non-motile, or capable of only limited movement along an autotrophic organism – a plant capable of synthesizing its own food substrate by secretion of mucilaginous material along a slit-like groove or channel called a raphe.

Being autotrophic they are restricted to the photic zone (water depth down to about two hundred meters depending on clarity).

There is also a planktic zone that includes a collection of small or microscopic organisms, including algae and protozoans that float or drift in great numbers in fresh or salt water, especially at or near the surface, and serve as food for fish and other larger organisms.

There is also a benthic zone which is an ecological region at the lowest level of a body of water such as an ocean or a lake, including the sediment surface and some sub-surface layers. Organisms living in this zone are called benthos. They generally live in close relationship with the substrate bottom; many such organisms are permanently attached to the bottom.

The superficial layer of the soil lining the given body of water, the benthic boundary layer, is an integral part of the benthic zone, as it influences greatly the biological activity which takes place there.

Examples of contact soil layers include sand bottoms, rock outcrops, coral, and bay mud. Pennate diatoms, which developed later in the earth's history, are able to locomote in a slow gliding fashion in the direction of the length of the cell.

The mechanism for this is still not well understood but it seems that through the slit alongside the cell (the raphe)may have tiny protruding microfibrils with which they can move over a surface.

Diatoms are formally classified as belonging to the division Chrysophyta, class Bacillariophyceae.

The Chrysophyta are algae which form endoplasmic cysts, store oils rather than starch, possess a bipartite cell wall and secrete silica at some stage of their life cycle. Diatoms are commonly between 20-200 microns in diameter or length, although sometimes they can be up to two millimeters long.

The cell may be solitary or colonial (attached by mucous filaments or by bands into long chains). Diatoms may occur in such large numbers and be well preserved enough to form sediments composed almost entirely of diatom frustules (diatomites), these deposits are of economic benefit being used in filters, paints, toothpaste, and many other applications.

Bacillariophyta are diatoms. With their exquisitely beautiful silica shells, or frustules such as that of Odontella diatoms are among the loveliest microfossils. They are also among the most important aquatic microorganisms today:

They are extremely abundant both in the plankton and in sediments in marine and freshwater ecosystems, and because they are photosynthetic they are an important food source for marine organisms. Some may even be found in soils or on moist mosses.

Diatoms have an extensive fossil record going back to the Cretaceous age; some rocks are formed almost entirely of fossil diatoms, and are known as diatomite or diatomaceous earth. These deposits are mined commercially as abrasives and filtering aids.

Analysis of fossil diatom assemblages may also provide important information on past environmental conditions.

Red Tide negligible with very minute traces in Lee and Sarasota counties

Karenia brevis, the Florida red tide organism, was not detected in water samples collected this week in the Indian River System Brevard and Indian River counties) nor alongshore of Escambia County. In the southwest coast the Florida, red tide organism, was not detected in water samples collected this week alongshore of Pinellas, Hillsborough, Manatee, Charlotte, Collier and Monroe counties or offshore of Lee and Monroe counties. One sample (out of 27 total) collected alongshore of Sarasota County and one sample (out of 9 total) collected alongshore of Lee County contained background concentrations of K. brevis.

The fishing report shows good results as the weather continues to warm up

The surf sea water temperatures over the past week have been in the 60s. The anglers fishing from the piers and the surf are catching a few pompano and the whiting. Murky water and rougher than normal water have been influencing the fishing conditions adversely.

In the Tomoka basin, they are catch ling large trout, redfish and ladyfish. In Ponce Inlet, anglers have sheepshead, redfish and black drum in the back waters and the adjacent creeks. In the lagoon, large schools of redfish are breaking up into smaller schools. Water is slightly high. Fishing has been fair.Pigfish are the ‘ticket for success.’

The incoming tide seems to be best for trout.in the Tomoka area. Redfish and ladyfish are also plentiful. Offshore fishing continues to be good, Cobia are being caught a couple miles off of the beach. Further offshore, dolphin, mackerel, blackfin tuna and wahoo have been filling the angler’s coolers.

HEAD

Recently the EPA announced plans to hold ``listening sessions'' on March 18 and April 29, to provide information about the Clean Boating Act, and to gather recommendations from the public for forthcoming regulation of recreational vessels under the Clean Water Act, Section 312(o). The listening sessions will be held in Annapolis, Md. EPA may hold additional listening sessions in other locations if there is sufficient interest.

The CBA, which was passed by Congress and signed into law in 2008, directs EPA to promulgate regulations to establish management practices and associated standards of performance for discharges incidental to the normal operation of recreational vessels (e.g., bilge water, ballast water, and gray water).

Because these regulations will affect the owners and operators of approximately 17 million recreational vessels, EPA seeks to inform the general public and regulated community of its plans for development of the regulations, and to hear the views of the general public, the recreational boating community, State agencies, and other interested stakeholders. The listening sessions will be held at 210 Holiday Court, Annapolis, Md., on March 18 and April 29, 2011, at 7 p.m. EST.

Any additional listening sessions that are scheduled will be published in a forthcoming Federal Register document.

If you would prefer to provide written comments, EPA is asking for comments or relevant information from the interested public to be submitted to the docket on or before June 2. Submit your statements or input, identified by Docket ID No. EPA-HQ-OW-2011-0119 by one of the following methods- http://www.regulations.gov: Follow the on-line instructions for submitting comments.

Conference in South Carolina on spiny lobster and Goliath grouper

The South Atlantic Fishery Management Council will hold a meeting of its Scientific and Statistical Committee to review fishery management plan amendments under development, review stock assessments of spiny lobster and Goliath grouper, and discuss data available for supporting fishing level recommendations.

The meeting will be held April 5-7, at the Crowne Plaza Hotel, 4831 Tanger Outlet Blvd., in North Charleston, SC.: For further information please contact Kim Iverson, Ppublic information specialist by phone at 843-571-4366 or e-mail her at Kim.Iverson@safmc.net.

Capt. Budd's PostScript

It has been written that the charm of fishing is that it is the pursuit of what is elusive, but attainable; a perpetual series of occasions for hope.

So whether you charter, ride a head boat, run your own vessel, stay in the river, surf fish or fish from shore or a bridge, there are fish to be caught. Fishing is not a matter of life and death, it is so much more important than that.

Tight lines, Capt.. Budd.

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About the Blogger

Capt. Budd Neviaser's picture

Capt. Budd Neviaser
Capt. Budd Neviaser is a life-long resident of New Smyrna Beach who has fished the Intracoastal waterways and the Atlantic Ocean most of his life.

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