You have probably seen it, maybe even slipped on it the last time you went fly fishing, but have you ever wondered about the slimy stuff growing on the bottom of our streams and rivers? That slippery slime is probably some kind of algae, and it’s part of the natural ecology of our rivers and streams.
Exactly what algae communities’ impact on environmental health is and methods to determine which factors are most heavily controlling their distribution are developing topics both locally and nationally.
Recent sampling conducted by CCWC (with the support of partners) indicated that algae concentrations in Crested Butte's local watersheds are within the state’s current standard.
Climate and Hydrology
Seasonal temperatures, climate driven events, and the way water moves through an ecosystem affect algal growth and development in various ways. In high alpine environments, spring snowmelt typically scours algae from river bottoms allowing for a fresh start in the summer. However, years with a smaller snowpack see weaker spring runoff and flows fail to fully clean streambeds, resulting in larger amounts of algae the following summer. Other climatic events such as drought and fire can also alter algae growth patterns.
Riverbed materials vary in different environments and can include bedrock, cobble, sand, silt, and wood. The size of riverbed material present in a stream determines the amount of surface area available, controls access to light, and influences invertebrate communities, therefore affecting algae’s ability to grow and reproduce.
Algae are at the base of aquatic food webs, which means they are usually being eaten by other organisms. Some invertebrates, commonly referred to as “bugs”, consume algae. Generally, fish eat the bugs that consume the algae. These relationships between algae, bugs, and fish influence algae growth and distribution.
When algae have access to high quantities of nutrients, they can grow faster and become more abundant. Nutrients occur naturally in any stream system. For example, when leaves fall off of trees in autumn, they decompose and add nutrients to rivers and streams. Human inputs such as agriculture, stormwater, and wastewater runoff also deliver nutrients to stream systems.
All aquatic life, including algae, can be impacted by water chemistry. Many species have a range of water chemistry conditions that they do well in. For example, if a particular stream had a high concentration of arsenic, many species of algae and bugs would have difficulty growing and surviving.
Coal Creek Watershed Coalition
PO Box 962
Crested Butte, CO 81224
← 3% Fundraising + 14% Administrative
In recent years 83% of Coal Creek Watershed Coalition's total operating expenses were used for projects and programs that benefit our local watersheds. Learn More >