Southeastern Plankton Monitoring Network (SEPMN)

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On April 11, 2007, I gathered my first plankton sample (on my own) as instructed by NOAA's SEPMN (Southeastern Phytoplankton Monitoring Network), Jeff Paternoster. Data is collected and monitoring for toxic phytoplankton blooms along the Atlantic, and entered into the national database. It's a network of volunteers, and NOAA provides training and equipment free of cost.

The slide contained numerous organisms, which I've photographed and (slowly) placing at my page on the 4/11/2007 Phytoplankton Count. The microscope slide (provided by SEPMN) contains a vertical row A-H and a horizontal row from 1-8. Thus, I've broken down each set of photos into groups A-1, A-2, A-3... presently I've only made it to the B's.
One of the most interesting critters I ran up on so far, was this guy:

I'm waiting for a positive identification, but this critter looks like it may have broken from its chain and bears resemblance with Chaetoceros. However, it may be a single organism. At this point, I'm uncertain, and waiting for an expert to id the genus.
Jeff told me the reason these creatures have such long appendages is because it gives them size, not weight, which equates to increased bouyancy in the water. Pretty efficient...

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Ceratium furca - Dinoflagellate

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Fig. 47
Ceratium furca - Dinoflagellate
Microscope Magnification 100x with additional digital camera magnification 4-∞
More images from April 4, 2007 plankton sample.
Ceratium furca - Dinoflagellate, Video #1, captured from sample from Atlantic Ocean on April 4, 2007. Ceratium furca, a dinoflagellate from the Atlantic Ocean. Recorded at 100x magnification on Microscope, with additional magnification of 4-∞ using digital camera.

Hydrogen Sulfide Poisoning
In March 1994, St. Helena Bay on South Africa’s West Coast experienced a massive marine mortality. The event was caused by the decay of a huge red tide of non-toxic dinoflagellates (dominated by Ceratium furca and Prorocentrum micans). About 60 tons of rock lobster and 1500 tons of fish were washed ashore. The lobster and fish died from suffocation and hydrogen sulfide poisoning. Oxygen concentrations were near zero and hydrogen sulfide concentrations were in excess of 50 micromols per liter!
HARMFUL (non-toxic) BLOOMS
What are dinoflagellates? and why are they important?
Dinoflagellates are microscopic, (usually) unicellular, flagellated, often photosynthetic protists, commonly regarded as "algae" (Division Dinoflagellata). They are characterized by a transverse flagellum that encircles the body (often in a groove known as the cingulum) and a longitudinal flagellum oriented perpendicular to the transverse flagellum. This imparts a distinctive spiral to their swimming motion. Both flagella are inserted at the same point in the cell wall, by convention defining the ventral surface. This point is usually slightly depressed, and is termed the sulcus. In heterotrophic dinoflagellates (ones that eat other organisms), this is the point where a conical feeding structure, the peduncle, is projected in order to consume food. Dinoflagellates possess a unique nuclear structure at some stage of their life cycle - a dinokaryotic nucleus (as opposed to eukaryotic or prokaryotic), in which the chromosomes are perminently condensed. The cell wall of many dinoflagellates is divided into plates of cellulose ("armor") within amphiesmal vesicles, known as a theca. These plates form a distinctive geometry/topology known as tabulation, which is the main means for classification.
Both heterotrophic (eat other organisms) and autotrophic (photosynthetic) dinoflagellates are known. Some are both. They form a significant part of primary planktonic production in both oceans and lakes. Most dinoflagellates go through moderately complex life cycles involving several steps, both sexual and asexual, motile and non-motile. Some species form cysts composed of sporopollenin (an organic polymer), and preserve as fossils. Often the tabulation of the cell wall is somehow expressed in the shape and/or ornamentation of the cyst.
Producers of Toxins
Besides being important primary producers, and therefore an important part of the food chain, dinoflagellates are also known for producing nasty toxins, particularly when they occur in large numbers, called "red tides" because the cells are so abundant they make the water change colour. Besides being bad for a large range of marine life, red tides can also introduce non-fatal or fatal amounts of toxins into animals (particularly shellfish) that may be eaten by humans, who are also affected by the toxins. Many of these toxins are quite potent, and if not fatal, can still cause neurological and all sorts of other nasty effects. Add this to the rather ominous suspicion that red tides may be more common thanks to human inputs of phosphates and warmer global temperatures, and you can probably see why we have a vested interest in finding out more about them - both medical and economic.
Source: geo.ucalgary.ca

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Diatoms

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After observing diatoms under the microscope at length I've noticed some of those normally seen as loosely floating diatoms are hooked together, aside of the obvious with chain diatoms. Chain diatoms it turns out, are due to their asexual reproduction habits... the cell divides, and a chain builds over time.

Figure 1 and 2

Sexual reproduction "Diatoms can reproduce in two different modes, sexual and asexual. Diatoms have a unique "shrinking division" mode of asexual reproduction. After cell division, the two valves of the test separate. Each forms the epivalve of a daughter cell, and new hypovalves are secreted within each of the parent valves. The result is one cell that is the same size as the parent cell, and one cell that is slightly smaller. Due to the rigidity of the test material, growth of the cell is impossible once the test is secreted. Thus, the average diatom size gets progressively smaller with each round of replication."

Figure 3 and 4
Diatom life history and interannual variation in diatom community composition
"The typical diatom life cycle is composed of many generations of asexual cell division and cell size decrease until a episode of sexual reproduction restores the maximum cell size. Populations that are unable to reproduce sexually will eventually go extinct. For many species of planktonic diatoms, sexual reproduction has never been observed and very few of the observations are of free-living populations, presumably because the episodes are typically brief (days to weeks in duration) and rare (years to decades apart)."

Figure 5 and 6

"Diatoms are unicellular (single cell) alga which are lumped in with other organisms and collectively referred to as plankton. Diatoms belong to the Kingdom Protista and the phylum Bacillariophyta. They inhabit both freshwater and marine environments as well as semi-aquatic and moist habitats. Diatoms live free floating, attached to a substratum (plants, sand, rock and animals), or joined to each other. They accomplish this by way of a gelatinous extrusion used for attachment and locomotion (some species). Diatoms are primary producers that contain chlorophyll a and c and the carotenoid fucoxanthin which accounts for their golden brown color. Their cell wall is composed of silica (silicon dioxide) and can be very ornate. Diatomaceous earth (dirt with diatom “shells”) is mined and used as polishes (toothpaste), abrasives, filter components and insecticide. Diatoms reproduce asexually by dividing the frustule in half. The frustule is composed of the epivalve and hypovalve. With each asexual reproduction, the diatoms are reduced in size until the diatom undergoes sexual reproduction. After sexual reproduction, the original size of the diatom is re-established and the process begins anew.
The monitoring of streams, rivers and lakes to insure water quality is extremely important. It is known that individual species of diatoms have specific and well defined water quality tolerances."
From Diatoms Web Page, John Carroll University

Figure 7 and 8

Diatoms are the most common phytoplankter. They are one celled producers... [and] are important oxygen producers in marine ecosystems (usually the first step in the food chain).
Asexual reproduction occurs with diatoms in good conditions in a unique way so that some get smaller and smaller until they are too small to function properly. This occurs when each frustule makes a new part - the original epitheca makes a new hypotheca inside the reproducing diatom resulting in a diatom the same size as the original diatom. The original hypotheca makes a new piece of frustule that will become a hypotheca inside the reproducing diatom - the original hypotheca now becomes an epitheca resulting in a diatom smaller than the original diatom. If this goes on for many divisions (as happens when conditions are very good and splitting can occur every few hours) there are a wide variety of diatom sizes concentrated in the water - some large and many small. The very tiny ones can no longer carry on cellular activities - these are the ones that become sexual. They form eggs or sperm (depending on their sex that was not obvious before). The sperm is released and when it fertilizes an egg the resulting zygote drops the tiny frustule, swells up to a large size and secrets a new large frustule.
From Marine Life: Plankton

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