Founded in 1999, BrainPOP creates animated, curriculum-based content that engages students, supports educators, and bolsters achievement.
Here is a content about Algae:
What are all those little green plants covering your lake? It’s more than just pond scum, it’s algae! In this BrainPOP movie, Tim and Moby teach you all about algae, including where they fall in the tree of life and what physical characteristics these organisms have. You’ll learn the differences between several categories of algae, including green algae, red algae, brown algae, euglenoids, diatoms, and dinoflagellates. You’ll also find out about algae’s place in the food chain and what uses algae serve for humans. Finally, learn about some environmental problems associated with algae, including their contribution to red tide. It’s time to give algae their proper due!
Watch the Science movie about Algae….
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I found a small beginner’s guide for those, who decided or have algae in their aquarium and i have also created a new category for this called Aquarium Algae.
Not all algae in the aquarium is necessarily ‘bad’ – a certain amount is inevitable where there is water, light and nutrients. However, some types of algae are certainly a nuisance, if for no other reason than looking unsightly.
The control or prevention of different algae types is primarily about nutrient control, and the amount of light. There are therefore some general guidelines which can be followed to help minimise algae:
Avoid direct sunlight falling on the tank, especially for prolonged periods. Unfortunately, despite the pleasant rippling light effects provided by sunlight, the rich lighting spectrum of the sun is likely to mean a constant battle against algae in most setups.
Do not leave lighting on for more than 10-12 hours a day. Longer periods are likely to favour algal growth, rather than promote plant growth.
Minimise nutrient levels with frequent water changes.
In particular, it may help to keep nitrates, phosphates and silicates low if you have a persistant problem – either by the use of reverse osmosis (RO) or deionised (DI) water, or specific adsorption resins (e.g. API Phos-Zorb). However, note that although high levels of such nutrients may encourage algae, it is not generally possible to completely eliminate algae by attempting to reduce them, as algae can survive at levels below those which can be measured by a hobbyist test kit.
Phosphate adsorbing resin and test kit
Consider adding algae eating fish if appropriate to the setup. These include: suckermouth catfish (e.g. Ancistrus, Peckoltia and Otocinclus species), the Siamese Algae Eater (Crossocheilus siamensis) and mollies.
Note that in planted tanks (which is not really the same as tanks with a few plants in!), the most effective way to control algae growth is to plant heavily and promote vigorous plant growth of several different species, to out-compete the algae for nutrients. The management of a planted aquarium is beyond the scope of this article, and will be the subject of a future article, but an important nutrient with regard to plant versus algae growth in a planted tank is Iron, and controlling levels of this nutrient is likely to be important.
The taxonomy of algae and related organisms is complex, but for the purpose of identification in the aquarium, they can be conveniently grouped into the following:
More details you will find here ( Source ): http://www.thetropicaltank.co.uk/algae.htm
Dr. Timothy Devarenne, AgriLife Research scientist with the Texas A&M University department of biochemistry and biophysics points out, “Oils from the green algae Botryococcus braunii can be readily detected in petroleum deposits and coal deposits suggesting that B. braunii has been a contributor to developing these deposits and may be the major contributor. This means that we are already using these oils to produce gasoline from petroleum.” He’s implying rather directly that green algae producing hydrocarbon oil as a biofuel production process is nothing new; nature has been doing so for hundreds of millions of years.
Devarenne explains B. braunii is a prime candidate for biofuel production because some races of the green algae typically “accumulate hydrocarbons from to 30 percent to 40 percent of their dry weight, and are capable of obtaining hydrocarbon contents up to 86 percent of their dry weight.” These are impressive numbers. “As a group, algae may be the only photosynthetic organism capable of producing enough biofuel to meet transportation fuel demands,” he says.
Devarenne is part of a team comprised of other scientists with AgriLife Research, the University of Kentucky and the University of Tokyo trying to understand more about B. braunii, including its genetic sequence and its family history. The point is, “Without understanding how the cellular machinery of a given algae works on the molecular level, it won’t be possible to improve characteristics such as oil production, faster growth rates or increased photosynthesis,” he says.
B. braunii, like most green algae, is capable of producing great amounts of hydrocarbon oils in a very small land area. B. braunii algae show particular promise not just because of their high production of oil but also because of the type of oil they produce.. While many high-oil-producing algae create vegetable-type oils, the oil from B. braunii, known as botryococcenes, are similar to petroleum.
Devarenne explains, “The fuels derived from B. braunii hydrocarbons are chemically identical to gasoline, diesel and kerosene. Thus, we do not call them biodiesel or bio-gasoline; they are simply diesel and gasoline. To produce these fuels from B. braunii, the hydrocarbons are processed exactly the same as petroleum is processed and thus generates the exact same fuels. Remember, these B. braunii hydrocarbons are a main constituent of petroleum. So there is no difference other than the millions of years petroleum spent underground.” He is almost making a new explanation of the formation of fossil fuels – which in this process wouldn’t be “fossil” at all. Interesting.
B. braunii has a problem – a relatively slow growth rate. While the algae that produce ‘vegetable-type’ oils may double their growth every six to 12 hours, B. braunii’s doubling rate is about four days. Devarenne says, “Thus, getting large amounts of oil from B. braunii is more time consuming and thus more costly. So, by knowing the genome sequence we can possibly identify genes involved in cell division and manipulate them to reduce the doubling rate.”
Here’s a surprise for you. Despite these characteristics and economic potential of algae, only six species of algae have had their genomes fully sequenced and annotated, Devarenne said. And B. braunii is not one of the six. I was surprised at such a low number too. Craig Venter with the Exxon effort must likely be on this as well as others, all with proprietary data.
Another point that may be delaying the genetic work is the nature of the algae. Devarenne explains, “Genomes with high guanine-cytosine content can be difficult to sequence and knowing the guanine-cytosine content can help to assess the amount of resources needed for genome sequencing,” Guanine-cytosine bonds are one of base pairs composing DNA structure. Adenine-thymine is the other possible base pair.
Devarenne and his colleagues are working the Berkeley strain of the B race of B. braunii, so named because it was first isolated at the University of California at Berkeley. The team has determined the genome size and an estimate of the B race’s guanine-cytosine content, both of which are essential to mapping the full genome, he said. There are also races A and L of B. braunii, but they were not looked at by the team.
The team has determined B. braunii’s genome size to be 166.2 ± 2.2 million base pairs, Devarenne said. In comparison the size of the human genome is about 3.1 billion base pairs. The genome of the house mouse is also about 3 billion base pairs. But the B. braunii genome size is larger than any of the other six previously sequenced green algae genomes.
The actual genome sequencing and mapping will be performed by Department of Energy’s Joint Genome Institute.
“We’ve submitted genomic DNA from B. braunii for the Joint Genome Institute to use in sequencing, but that hasn’t begun yet,” Devarenne said.
Its not new or a secret that B. braunii is an interesting algae. Rather the news is that now the sophistication and depth of research is getting much further into the field – and it’s a very big field. Pulling out genomes from algae known to form essentially petroleum oil is quite fascinating. The matter remains to be seen if modification skill can push productivity to comparable levels with vegetable oil producing species. Then the list of production issues must be solved.
If B. braunii or its close cousins can be modified to get to high production and the other production issues have solutions, the oil supply issue will begin its decent into history.
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Characteristics: Green colour from chlorophyll a and b in the same proportions as the ‘higher’ plants; beta-carotene (a yellow pigment); and various characteristic xanthophylls (yellowish or brownish pigments). Food reserves are starch, some fats or oils like higher plants. Green algae are thought to have the progenitors of the higher green plants but there is currently some debate on this point.
Green algae may be unicellular (one cell), multicellular (many cells), colonial (living as a loose aggregation of cells) or coenocytic (composed of one large cell without cross-walls; the cell may be uninucleate or multinucleate). They have membrane-bound chloroplasts and nuclei. Most green are aquatic and are found commonly in freshwater (mainly charophytes) and marine habitats (mostly chlorophytes); some are terrestrial, growing on soil, trees, or rocks (mostly trebouxiophytes). Some are symbiotic with fungi giving lichens. Others are symbiotic with animals, e.g. the freshwater coelentrate Hydra has a symbiotic species of Chlorella as does Paramecium bursaria, a protozoan. A number of freshwater green algae (charophytes, desmids and Spirogyra) are now included in the Charophyta (charophytes), a phylum of predominantly freshwater and terrestrial algae, which are more closely related to the higher plants than the marine green algae belonging to the Chlorophyta (known as chlorophytes). Other green algae from mostly terrestrial habitats are included in the Trebouxiophyceae, a class of green algae with some very unusual features.
Asexual reproduction may be by fission (splitting), budding, fragmentation or by zoospores (motile spores). Sexual reproduction is very common and may be isogamous (gametes both motile and same size); anisogamous (both motile and different sizes – female bigger) or oogamous (female non-motile and egg-like; male motile). Many green algae have an alternation of haploid and diploid phases. The haploid phases form gametangia (sexual reproductive organs) and the diploid phases form zoospores by reduction division (meiosis). Some do not have an alternation of generations, meiosis occurring in the zygote. There are about 8,000 species of green algae, about 1,000 of which are marine chlorophytes and the remainder freshwater charophytes. Unfortunately, just because algae are green no longer means that they are related: two major aggregation of green algae, the Chlorophyta and the Charophyta have turned out not be remotely related to each other.
Commercial uses: Organic beta-carotene is produced in Australia from the hypersaline (growing in high salinity water often known as brine) green alga Dunaliella salina grown in huge ponds. Carotene has been shown to be very effective in preventing some cancers, including lung cancer. Caulerpa, a marine tropical to warm-temperate genus, is very popular in aquaria. Unfortunately, this has led to the introduction of a number of Caulerpa species around the world, the best-known example being the invasive species Caulerpa taxifolia.
Chlorella, a genus of freshwater and terrestrial unicellular green alga with about 100 species, is grown like yeast in bioreactors, where it has a very rapid life history. It may be taken in the form of tablets or capsules, or added to foods such as pasta or cookies. Taken in any form, it is said improve the nutritional quality of a daily diet. According to the Taiwan Chlorella Manufacturing Company the increase in processed and refined foods in the diet of modern man make Chlorella an important food supplement for anyone interested in better health.