Can I please have some help identifying this brown stuff that grows on the rocks around my pond (northeast Indiana)? I have searched the Internet, including the Texas A&M page that I’ve seen here, but most pictures have a huge green mat of something floating on the pond, and mine is usually just on the rocks. I use some copper to control the Chara on my beach, but the copper doesn’t make this go away. Any input on how to control this and when it’s best to do that would be greatly appreciated.
Could be filamentous algae or Periphyton which is a complex mixture of algae, cyanobacteria, heterotrophic microbes, and detritus that is attached to submerged surfaces in most aquatic ecosystems.
Periphyton is a whole community of living organisms that have organic dertitus and silt incorporated among the growth layer. Also living in the community layer are invertebrates, microscopic animals and even decomposer bacteria. There are literally thousands of different types of algae that compose the many, many different species that are able to live in the attached layer. The types of species present depend on the many various types of growing conditions. Each different condition will favor a different periphyton community. Periphyton and phytoplankton both comprise the aquatic food web. This primary production produces a lot of dissolved oxygen for the water where both forms of the algae are growing.
The conditions in the water body determine what type of periphyton grows there. The particular type of stuff growing on the rocks in Heidi's above picture is a unique group of periphyton that tolerates and grows well in the presence of the current concentration of blue pond dye and maybe the past use of algaecides that have eliminated other common species of periphyton such as green algae, filamentous algae, and diatoms.
Three very different types of periphyton from three very different ecosystems. Each one has a very different community of inhabitants.
I surely wouldn’t want to remove it from your pond with that beautiful water! It is likely a big part of your current water quality and a healthy part of your pond’s ecosystem.
A pond owner can't really do a lot to grow the best types of periphyton other than maintaining good water quality and providing substrates for it to grow on. All periphyton are attached forms of mostly "algae" growth. If it cannot get an adequate amount of light it will not grow. Turbid water restricts the depth at which periphyton will grow and thrive. Some types of periphyton are loosely attached. When it breaks lose from the substrate it is often called tychoplankon. What grows as periphyton depends on the quality of water and the nutrients that are present. The more nutrients that are present causes more periphyton to grow and some of it can be filamentous algae or mats of cyanobacteria and they can be a big nuisance as in too much uncontrolled and unwanted growth/s. The type of periphton that grows is directly related to the water quality. Many of the periphytic species are indicators of the water quality conditions. The type of periphyton that grows and the species composing it are direct results of the water quality conditions that it has to live in or substrates it grows on.
