The 100,000 species of diatoms are grouped under 200 genera.
Diatoms are found in freshwater bodies like rivers and lakes, and also in oceans.
The characteristics of diatoms are that:
Since diatoms are often the dominant component of thespring maximum in temperate lakes, silica concentrations are often reducedto limiting levels (
The silica of the diatom cell wall is resistant to decay, although it will begin to dissolve once its organic coating has been stripped off. Once incorporated into silica-rich sediments, however, frustules may survive for hundreds to millions of years and can be used to monitor changes in freshwater or marine environments. The left-hand picture above shows a spread of living diatoms and other algae from a freshwater loch in Scotland. Each cell contains one to several brownish chloroplasts. Shown in the right-hand (false-colour) picture is a subfossil assemblage from a muddy deposit a few metres below the surface of a mire in SW Scotland. Here, all the cells are empty - only the cell walls remain; indeed, in many cases the cell walls have fallen apart into their component pieces. But it is still possible to identify them, because the walls retain their shape and pattern. Consequently, if the ecologies of the species are known, then the fossil assemblage can be used to estimate what conditions were like when it was formed. In the assemblage illustrated there are both planktonic species (the circular Cyclotella valves) and benthic species, which have become mixed together after death.
The diatom quotient issupposedly applicable at any time of year.
There is what I consider seven categories of problematic algae and bacteria slime-like growths that cause aquarists the most problems. They are hair algae (long hair-like or plume-like growths); slime algae; turf algae; bubble algae; brown diatom algae; dinoflagellates; and, a very specific green microalgae.
I've found most preferable species of red algae to be quite sensitive to slight changes in water chemistry. Just what those elements or compounds may be, I am not sure but have seen perfectly good specimens quickly disintegrate overnight, even when there were no apparent changes to water quality. Therefore, trace element additions are advised if the goal is keeping any of these species.
Diatoms and photosynthesis - Science Is Art
Therefore, first make a decision as to what animal species and quantity will ultimately live in the system. Then choose the filtration techniques to adequately support that bio-load and don't exceed that bioload. Keep in mind, if bioload is increased, i.e., aquarist attempts to stuff six pounds of waste into a five-pound bag, green is very possibly a forthcoming color in the aquarium! Nevertheless, when bioload and filtration techniques are properly match and not exceeded, an almost algae free aquarium is very possible!
Over the past few decades I've heard of many remedies that have worked well for aquarists. Some may be extremely helpful in one situation and not so in others. To be more concise, I've divided this section into subsections beginning with those remedies that are wide ranging and encompass hair algae and turf algae problems. Then note those that are more applicable to diatoms, dinoflagellates, and cyanobacteria.
What are diatoms?:: Diatoms of the United States
The diatoms are one of the largest and ecologically most ..
Anything either highly acid or alkaline would kill marine life but the oceans are very stable with regard to pH.
Photosynthesis and Formation of Fats in a Diatom | …
More than 200 genera of living diatoms are known, with an estimated 100,000 extant species
To test the role of PEPCase in diatom photosynthesis, ..
Diatoms and photosynthesis
Efficiency of the CO2-concentrating mechanism of diatoms
Mann and Marchant (1989) suggested that another group, the Parmophyceae, may also be closely related to diatoms and thus may give hints as to how diatoms arose, because they produce silica scales that in some respects (radial pattern subtended by a central ring, space-filling development of pattern) resemble diatom valves and girdle bands. So far, no DNA sequences have been confirmed to be derived from Parmophyceae, but a clade of unknown heterokonts closely related to diatoms and bolidophytes has been detected by Lovejoy et al. (2006) and may represent the Parmophyceae; it is certainly important for understanding the evolution of both bolidophytes and diatoms that the organisms detected by Lovejoy et al. are fully characterized.
Efficiency of the CO 2-concentrating mechanism of diatoms ..
Two marine dinoflagellates, Hulburt and Stein, demonstrate active uptake of carbon dioxide (or carbonic acid), but not bicarbonate. Because this mechanism is fundamentally limited in its effectiveness, it has been speculated that these organisms may be CO2-limited in their natural environment. These species would likely be stressed considerably if the pH of a reef aquarium containing them were raised substantially. On the other hand, three marine bloom-forming (red tide) dinoflagellates, , and , have been shown to take up bicarbonate directly, with bicarbonate accounting for approximately 80% of the carbon dioxide they use in photosynthesis. It is believed that these dinoflagellates are not carbon limited in photosynthesis due to their efficient direct bicarbonate uptake mechanisms, so they may not be overly stressed (by this mechanism) by raising the pH to levels achievable in a reef aquarium.
The Photosynthesis of diatom cultures in the sea
In the past, it was sometimes suggested that diatoms evolved well before their appearance in the fossil record and that the early phases in diatom evolution were lost long ago through diagenesis of diatomites to chert (e.g. Round 1981). This is made extremely unlikely by recent molecular phylogenies, which date the origin of diatoms towards the beginning of the Mesozoic Era. Furthermore, a close relationship to other silica scale or silica skeleton-producing algae and protists, such as the Chrysophyceae, is not evident in recent analyses. The closest known relatives of the diatoms are the bolidophytes (Bolidophyceae), which are a small group of marine autotrophic picoplankton with the same kind of plastids and flagellum structure as diatoms and some other autotrophic heterokonts (Guillou et al. 1999). However, bolidophyte cells are highly reduced and simplified and do not seem to produce any silica structures, although it is possible that silicifying life cycle stages have been missed.
What Does the Diatom Do in the Ecosystem? | Sciencing
There are many forms of algae; no matter what their color, that serve useful purposes. Those could be a food source; decorative purpose; inhabitant shelter; or a means to export nutrients such as those used in refugia or alga turf filters. It would be far beyond the scope of this book to name all the species that can show up in aquaria or in the trade. However, I'll discuss the more commonly seen species in relation to what's the most beneficial in this topic and in the 'Unwanted' topic below discuss those species that have the potential to create problems in the aquarium and/or give some aquarists gray hair!
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