Algae

Torch Lake Algae

Algae occur naturally in Torch Lake and its tributaries. Algae are an important food source for other organisms that live in Torch Lake.

Key Facts

• Algae contains chlorophyll, so they can make their own food through photosynthesis.
• Algae are aquatic plants that lack true stems, roots and leaves.
• There are over 700 known species of algae in Michigan lakes.
• Algae can be found in two places in the water:

Suspended in the water column – phytoplankton

On the bottom surface of the lake – benthic algae

Did You Know?

Algal blooms are occurring more frequently and are more widespread due to:

• Warmer water temperatures
• More nutrients like phosphorus and nitrogen entering water from
  • Farms-fertilizers from crop farms and manure for livestock farms
  • Sewage systems
  • Storm run off from developed areas with impervious surfaces

Algal Blooms

Non-toxic algal blooms

Torch Lake, since the summer of 2014, has been experiencing a bloom of Golden Brown Algae on the bottom of lake. Initial findings indicate the algae is composed of a community or assemblage of diatom species. Diatoms are a type of single cell algae with glass or silica cell walls.

While most algal blooms occur on the water surface, this bloom is located on the lake bottom along the shallow shoals. The bloom is not dangerous to humans, but is considered a nuisance, because it changes the color of the lake water. It can also lead to changes in the amount of aquatic plants in the lake.

The Three Lakes Association is collaborating with professors at the University of Michigan Biological Station and Michigan State University to determine the cause of this recent growth.

In 2017, Michigan had 49 reports of algae from concerned citizens. This is up from 9 reports in 2013 when the program started.

Toxic algal blooms

Some species of algae can produce toxins. Toxins can make the water unsafe for swimming, boating and even drinking.

Lake Erie is known for having large algal blooms. In 2014, Toledo, Ohio had to shutdown their water supply after  toxic algae formed on Lake Erie near the city’s water-intake pipe.

In the summer of 2018, even Lake Superior, the largest of the Great Lakes, experienced an algal bloom that stretched 50 miles long. Dr. Robert Sterner of the University of Minnesota, Duluth identified the algae species in the bloom as a blue-green algae that could be toxic but tests showed the toxin was not at dangerous levels.

Types of Freshwater Algae

Algae can be grouped by size: Single cell, Multicellular filamentous or Small plant-like organisms.

Single cell algae

Phytoplankton

Single cell algae are microscopic and are the base of the aquatic food web. Phytoplankton are algae found suspended or floating in the water column.

Because Torch Lake water has low nutrient concentrations of nitrogen and phosphorus, the lake has little phytoplankton. This leads to clear water and good clarity.

Benthic algae

Benthic algae are single cell organisms found on the bottom of the lake growing on the sand, rocks or on large aquatic plants (macrophytes).

Torch Lake Shoreline

Algae Mats in Clam Lake

Use Natural Lawn Fertilizers

• Too much chemical fertilizer is applied to lawns and ends up making the lake green.

Plant Rain Gardens

• Around Driveways
• Near Perimeter Drainpipes

Plant Buffer Gardens along Shorelines