There are two distinct things people will be searching for when they use the search term “brown algae” and I will try to satisfy both of those on this one web page. The confusion is that there is a very common condition in aquariums, especially relatively new ones, that is very often called “brown algae” although it is not really algae at all! It is actually caused by diatoms although it looks like a brown algae in the aquarium, The term “brown algae” is not quite correct, as true brown algae (Phaeophyceae) are another group, which, with a few exceptions, does not occur in fresh water. Diatomaceous “Brown Algae” frequently occurs in both freshwater and saltwater aquariums. Use one of the blow links to click on which type of Brown Algae you are interested in.
Brown algae (also called gravel algae or silica algae) begin as brown patches on the gravel and/or glass of the tank. Once established, it can rapidly coat most surfaces of the aquarium with a thin, dark brown coating that is easily removed.
Unlike blue-green slime algae, it does not come off in large slimy sheets. These patches almost look furry. While they won’t hurt your fish, the algae will cloud the water and generally make your tank look less appealing. It’s also a sign that the chemistry of your tank isn’t at an optimum balance.
If you’ve owned a fish tank, you’re probably familiar with the dreaded brown mossy substance that can quickly take over your fish’s home. It’s often called brown algae and is especially common in new aquariums, which may cause concern for people new to owning fish. It is actually caused by diatoms disproportionately and temporarily being the predominant microfauna in the tank.
In general, brown algae won’t harm your fish if you keep it under control. Some fish and animals do like to eat it and can help you clean up.
The good news is that this issue is pretty easy to clean up. Even without intervention brown algae problems usually resolve itself eventually. It’s also relatively easy to stop brown algae from growing in your aquarium if you know what causes it and even reverse a severe brown algae problem. A few preventative measures will have your tank looking great and algae-free.
There are several approaches to resolving a brown algae problem in an aquarium. My favorite is using beneficial microfauna to both clean up and permanently reduce the diatoms numbers and solving the issue within just a few days. This can also cure cloudy aquarium water also in the same way. The beneficial rotifers and copepods will actually both eat and outcompete the brown algae in the aquarium. The transformation literally takes place before your eyes within just a few days.
A wide variety of beneficial Freshwater and Saltwater Microfauna can be purchased from my friends at AquaCultureStore.com Once cleared the tank will have well balanced and established beneficial microfauna in the system and they will continue to provide balance and prevent further issues in the tank. The will also help control other algae issues and fish disease as well as act as a nitrate and nutrient “sponge” in the aquarium and provide food for corals, filter feeders, fish that feed on small organisms, and fish fry. Their function as a nitrate and nutrient “sponge” is also useful when used in conjunction with denitrification and will enhance the denitrification process.
Here is a complete package for saltwater aquariums that will most certainly naturally clear up your brown algae problem!
Coral Reefing Products, LLC
5 Bottle Package – Tisbe Pods, Tiger Pods, Marine Rotifers, Green Phyto(Nannochloropsis Oculata) and Gold Phyto(Isochrysis Galbana)
This Complete Live Package Includes:
600+ Live Tisbe Pods(Tisbe biminiensis)
500+ Live Tiger Pods(Tigriopus californicus)
8 oz. Bottle Marine Rotifers
8 oz. Bottle Live Green Phyto(Nannochloropsis Oculata)
8 oz. Bottle Live Gold Phyto(Isochrysis galbana)
Tiger Pods are microfauna loaded with crude fat and protein. Fish are drawn to the pods swimming through the water. Even troublesome feeders suck as Mandarin Gobies, Scooter Blennies, Anthias, and Butterfly Fish can’t resist our Live Tiger Pods. Tiger Pods can also greatly increase the color and appearance of the fish and coral in your aquarium. Loaded with beta-Carotene, brighter pigmentation will result in most any animals that eat Tiger Pods.
Tisbe Pods are a popular aquarium microfauna food source for many animals, including but not limited to mandarin gobies and other dragonettes, most carnivorous reef fish, young seahorses soft corals & many hard corals. As a colony flourishes in an aquarium, they are effective detritavores, eating excess detritus, fish food, some animal waste, etc., thus helping to clean cloudy aquarium water.
Many often forget the need for live phytoplankton, relying purely on a zooplankton diet. Without a premium phytoplankton diet, the base of the food chain suffers, thus affecting everything in the system. Additionally, many clams, gorgonians & other coral filter out only Phytoplankton, thus zooplankton diets are useless for these particular animals. Besides being a food source that generates the natural food for all tropic levels, Phytoplankton absorbs undesirable chemicals present in many reef aquariums, such as ammonia, nitrite, nitrates, phosphates, silicates, etc.
Live Rotifers and their eggs are a highly nutritious food source for your hard corals, young fish and macro inverts. Packed with protein, our Live Rotifers will promote the growth of most animals in your aquarium.
There are other approaches you can take to resolve brown algae issues if for some reason you do not want to take the microfauna route or do not have access to any microfauna.
Brown algae issue is generally pretty easy to clean. It comes off easily when you wipe off all surfaces and vacuum the gravel well. This type of algae does not adhere strongly to the tank surfaces and is easily wiped away. Vacuuming the gravel with a siphon will quickly remove coatings from the substrate. You should wipe off any tank decoration that may be affected as well.
Diatoms need silicate to grow, more exactly, silicon dioxide, since they construct their box-like cell walls from this substance. If you use tap water with high levels of silicate in your tank, diatoms have sufficient material to reproduce in a new tank. A lack of competitors like other algae and microorganisms will boost their reproduction rate.
After you clean the tank it will help to use silicate adsorbing resin in the filter. Apparently, phosphate remover also acts to remove silicate and so your favorite phosphate reducer should work just fine.
Specialized synthetic adsorption media that removes Phosphate and silicate from fresh and saltwater aquariums. The removal of silicate will help with brown algae problems. Treats up to 55 gallons. Treats up to 55 gallons 5.25 oz. pouch in jar treats up to 55 gallons.
Increasing the lighting will encourage the growth of phytoplankton and other microfauna that can eventually outcompete the brown algae.
Just as microfauna can help, some larger animals and fish will eat and help control brown algae as well. Plecostomus or several otocinclus fish and/or shrimp will help in freshwater tanks. A lot of hermit crabs, shrimp, and snails will do the trick in saltwater aquariums.
The Phaeophyceae or brown algae (singular: alga), are a large group of mostly marine multicellular algae, including many seaweeds located in colder Northern Hemisphere waters. They play an important role in marine environments, both as food and as habitats. For instance, Macrocystis, a kelp of the order Laminariales, may reach 60 m (200 ft) in length and forms prominent underwater kelp forests. Kelp forests like these contain a high level of biodiversity. Another example is Sargassum, which creates unique floating mats of seaweed in the tropical waters of the Sargasso Sea that serve as the habitats for many species. Many brown algae, such as members of the order Fucales, commonly grow along rocky seashores. Some members of the class, such as kelp, are used as food for humans. Worldwide, over 1500–2000 species of brown algae are known. They have environmental importance too through Carbon fixation.
Brown algae belong to the group Heterokontophyta, a large group of eukaryotic organisms distinguished most prominently by having chloroplasts surrounded by four membranes, suggesting an origin from a symbiotic relationship between a basal eukaryote and another eukaryotic organism. Most brown algae contain the pigment fucoxanthin, which is responsible for the distinctive greenish-brown color that gives them their name. Brown algae are unique among heterokonts in developing into multicellular forms with differentiated tissues, but they reproduce by means of flagellated spores and gametes that closely resemble cells of other heterokonts. Genetic studies show brown algae’s closest relatives to be the yellow-green algae.
Brown algae exist in a wide range of sizes and forms. The smallest members of the group grow as tiny, feathery tufts of threadlike cells no more than a few centimeters long. Some species have a stage in their life cycle that consists of only a few cells, making the entire alga microscopic. Other groups of brown algae grow to much larger sizes. The rockweeds and leathery kelps are often the most conspicuous algae in their habitats. Kelps can range in size from the two-foot-tall sea palm Postelsia to the giant kelp Macrocystis pyrifera, which grows to over 45 m (150 ft) long and is the largest of all the algae. In form, the brown algae range from small crusts or cushions to leafy free-floating mats formed by species of Sargassum.
Regardless of size or form, two visible features set Brown Algae apart from all other algae. First, members of the group possess a characteristic color that ranges from an olive green to various shades of brown. The particular shade depends upon the amount of fucoxanthin present in the alga. Second, all brown algae are multicellular. There are no known species that exist as single cells or as colonies of cells, and the brown algae are the only major group of seaweeds that does not include such forms. However, this may be the result of classification rather than a consequence of evolution, as all the groups hypothesized to be the closest relatives of the browns include single-celled or colonial forms.
Whatever their form, the body of all brown algae is termed a thallus, indicating that it lacks the complex xylem and phloem of vascular plants. This does not mean that brown algae completely lack specialized structures. But, because some botanists define “true” stems, leaves, and roots by the presence of these tissues, their absence in the brown algae means that the stem-like and leaf-like structures found in some groups of brown algae must be described using different terminology. Although not all brown algae are structurally complex, those that are typically possess one or more characteristic parts.
A holdfast is a rootlike structure present at the base of the alga. Like a root system in plants, a holdfast serves to anchor the alga in place on the substrate where it grows, and thus prevents the alga from being carried away by the current. Unlike a root system, the holdfast generally does not serve as the primary organ for water uptake, nor does it take in nutrients from the substrate. The overall physical appearance of the holdfast differs among various brown algae and among various substrates. It may be heavily branched, or it may be cup-like in appearance. A single alga typically has just one holdfast, although some species have more than one stipe growing from their holdfast.
A stipe is a stalk or stemlike structure present in an alga. It may grow as a short structure near the base of the alga (as in Laminaria), or it may develop into a large, complex structure running throughout the algal body (as in Sargassum or Macrocystis). In the most structurally differentiated brown algae (such as Fucus), the tissues within the stipe are divided into three distinct layers or regions. These regions include a central pith, a surrounding cortex, and an outer epidermis, each of which has an analog in the stem of a vascular plant. In some brown algae, the pith region includes a core of elongated cells that resemble the phloem of vascular plants both in structure and function. In others (such as Nereocystis), the center of the stipe is hollow and filled with gas that serves to keep that part of the alga buoyant.
Many brown algae have a flattened portion that may resemble a leaf, and this is termed a blade, lamina, or frond. The name blade is most often applied to a single undivided structure, while frond may be applied to all or most of an algal body that is flattened, but this distinction is not universally applied. The name lamina refers to that portion of a structurally differentiated alga that is flattened. It may be a single or a divided structure, and may be spread over a substantial portion of the alga. In rockweeds, for example, the lamina is a broad wing of tissue that runs continuously along both sides of a branched midrib. The midrib and lamina together constitute almost all of a rockweed, so that the lamina is spread throughout the alga rather than existing as a localized portion of it.
Some brown algae species like Fucus vesiculosus produce numerous gas-filled pneumatocysts (air bladders) to increase buoyancy.
In some brown algae, there is a single lamina or blade, while in others there may be many separate blades. Even in those species that initially produce a single blade, the structure may tear with rough currents or as part of maturation to form additional blades. These blades may be attached directly to the stipe, to a holdfast with no stipe present, or there may be an air bladder between the stipe and blade. The surface of the lamina or blade may be smooth or wrinkled; its tissues may be thin and flexible or thick and leathery. In species like Egregia menziesii, this characteristic may change depending upon the turbulence of the waters in which it grows. In other species, the surface of the blade is coated with slime to discourage the attachment of epiphytes or to deter herbivores. Blades are also often the parts of brown algae that bear the reproductive structures.
Gas-filled floats called pneumatocysts provide buoyancy in many brown algae species. These bladder-like structures occur in or near the lamina, so that it is held nearer the water surface and thus receives more light for photosynthesis. Pneumatocysts are most often spherical or ellipsoidal, but can vary in shape among different species.
Growth in Dictyota dichotoma occurs at each frond tip, where new cells are produced.
The brown algae include the largest and fastest growing of seaweeds. Fronds of Macrocystis may grow as much as 50 centimetres (20 in) per day, and the stipes can grow 6 centimetres (2.4 in) in a single day.
Growth in most brown algae occurs at the tips of structures as a result of divisions in a single apical cell or in a row of such cells. As this apical cell divides, the new cells that it produces develop into all the tissues of the alga. Branchings and other lateral structures appear when the apical cell divides to produce two new apical cells. However, a few groups (such as Ectocarpus) grow by a diffuse, unlocalized production of new cells that can occur anywhere on the thallus.
The simplest brown algae are filamentous—that is, their cells are elongate and have septa cutting across their width. They branch by getting wider at their tip, and then dividing the widening.
Aside from filamentous forms, there are two main types of tissue organization in the brown algae: pseudoparenchymatous (haplostichous) and parenchymatous (polystichous). The fronds may be multiaxial or monoaxial.
The cell wall consists of two layers; the inner layer bears the strength, and consists of cellulose; the outer wall layer is mainly algin, and is gummy when wet but becomes hard and brittle when it dries out.
Genetic and ultrastructural evidence place the Phaeophyceae among the heterokonts (Stramenopiles), a large assemblage of organisms that includes both photosynthetic members with plastids (such as the diatoms) as well as non-photosynthetic groups (such as the slime nets and water molds). Although some heterokont relatives of the brown algae lack plastids in their cells, scientists believe this is a result of evolutionary loss of that organelle in those groups rather than independent acquisition by the several photosynthetic members. Thus, all heterokonts are believed to descend from a single heterotrophic ancestor that became photosynthetic when it acquired plastids through endosymbiosis of another unicellular eukaryote.
The closest relatives of the brown algae include unicellular and filamentous species, but no unicellular species of brown algae are known. However, most scientists assume that the Phaeophyceae evolved from unicellular ancestors. DNA sequence comparison also suggests that the brown algae evolved from the filamentous Phaeothamniophyceae, Xanthophyceae, or the Chrysophyceae between 150 and 200 million years ago. In many ways, the evolution of the brown algae parallels that of the green algae and red algae, as all three groups possess complex multicellular species with an alternation of generations. Analysis of 5S rRNA sequences reveals much smaller evolutionary distances among genera of the brown algae than among genera of red or green algae, which suggests that the brown algae have diversified much more recently than the other two groups.
Most brown algae, with the exception of the Fucales, perform sexual reproduction through sporic meiosis. Between generations, the algae go through separate sporophyte (diploid) and gametophyte (haploid) phases. The sporophyte stage is often the more visible of the two, though some species of brown algae have similar diploid and haploid phases. Free floating forms of brown algae often do not undergo sexual reproduction until they attach themselves to substrate. The haploid generation consists of male and female gametophytes. The fertilization of egg cells varies between species of brown algae, and may be isogamous, oogamous, or anisogamous. Fertilization may take place in the water with eggs and motile sperm, or within the oogonium itself.
Certain species of brown algae can also perform asexual reproduction through the production of motile diploid zoospores. These zoospores form in plurilocular sporangium, and can mature into the sporophyte phase immediately.
In a representative species Laminaria, there is a conspicuous diploid generation and smaller haploid generations. Meiosis takes place within several unilocular sporangium along the algae’s blade, each one forming either haploid male or female zoospores. The spores are then released from the sporangia and grow to form male and female gametophytes. The female gametophyte produces an egg in the oogonium, and the male gametophyte releases motile sperm that fertilize the egg. The fertilized zygote then grows into the mature diploid sporophyte.
In the order Fucales, sexual reproduction is oogamous, and the mature diploid is the only form for each generation. Gametes are formed in specialized conceptacles that occur scattered on both surfaces of the receptacle, the outer portion of the blades of the parent plant. Egg cells and motile sperm are released from separate sacs within the conceptacles of the parent algae, combining in the water to complete fertilization. The fertilized zygote settles onto a surface and then differentiates into a leafy thallus and a finger-like holdfast. Light regulates differentiation of the zygote into blade and holdfast.
Brown algae have adapted to a wide variety of marine ecological niches including the tidal splash zone, rock pools, the whole intertidal zone and relatively deep near shore waters. They are an important constituent of some brackish water ecosystems, and four species are restricted to life in fresh water. A large number of Phaeophyceae are intertidal or upper littoral, and they are predominantly cool and cold water organisms that benefit from nutrients in up welling cold water currents and inflows from land; Sargassum being a prominent exception to this generalisation.
Brown algae growing in brackish waters are almost solely asexual.
Brown algae include a number of edible seaweeds. All brown algae contain alginic acid (alginate) in their cell walls, which is extracted commercially and used as an industrial thickening agent in food and for other uses. One of these products is used in Lithium Ion batteries. Alginic acid is used as a stable component of a battery anode. This polysaccharide is a major component of brown algae, and is not found in land plants.
Alginic acid can also be used in aquaculture. For example, alginic acid enhances the immune system of rainbow trout. Younger fish are more likely to survive when given a diet with alginic acid.
Brown algae including kelp beds also fix a significant portion of the earth’s carbon dioxide yearly through photosynthesis.
Sargachromanol G, an extract of Sargassum siliquastrum, has been shown to have anti-inflammatory effects.