Winter algae growth rarely gets to this nuisance level

Recent warm weather in North Carolina, and probably much of the rest of the country, is creating nuisance algae problems in lakes, ponds and stormwater devices. Property owners need to know why this is occurring, what can be done and what to expect in the spring. Filamentous algae is not attractive and provides few benefits. Nevertheless, control attempts at this time of the year may not be cost effective.

Biological activity is significantly reduced during winter in the lakes, ponds and stormwater devices we manage and maintain. The water is usually much more clear because plankton (tiny plants and animals living throughout the water column) growth and reproduction is directly related to water temperature. Sometimes increased runoff from winter rains produces suspended sediment that can cloud the water, but that runoff usually adds nutrients too.

• Causes for Filamentous Algae Blooms During Winter
  • Water is clearer; sunlight can reach more of the bottom
  • Runoff of surface water, usually containing nutrients, may occur more frequently
  • Brief warm spells can significantly warm the water along shallow shorelines
  • Aeration/circulation devices are often turned off during the winter
  • Cold water algae species are different and adapted to winter conditions
  • Biological controls such as fish, bacteria and enzymes are much less effective
  • Options for Managing Filamentous Algae During Winter
    • Live with it if it is not at a nuisance level. It is usually temporary and won’t cause any problems, particularly in early and mid-winter
    • Mechanically remove, with a dip net or rake, clumps or patches of algae
    • Reduce sunlight penetration with lake dyes or colorants
    • Use a peroxide based algaecide, which doesn’t require as much active uptake by the algae cells as copper based algaecides. Use granular formulations for bottom growing algae and liquids for surface growing algae
    • Determine if ultrasonic algae control devices are appropriate and cost-effective
    • Plan to improve the biological health of the lake or pond during the warm growing season so conditions don’t exist that encourage nuisance algae growth

The last point is particularly important for long term results. Since the biological and environmental activity is so much greater in warm water, improved conditions will often prevent winter algae problems.

• What You can do During the Summer
  • Reduce nutrients flowing into the lake, pond or stormwater device
  • Circulate and/or aerate the water
  • Determine if beneficial bacteria/enzyme products are recommended
  • Determine if sterile grass carp are needed and perhaps tilapia fish depending upon your management objectives
  • Plant beneficial plants along the shoreline or on floating rafts

Foster Lake & Pond Management provides the full range of lake, pond and stormwater BMP services and products. These include: construction, repairs, maintenance, certified inspections, fish stocking, fisheries management, lake mapping, vegetation management, docks, fountains and aeration.

We have provided aquatic and stormwater solutions to our North Carolina customers for 30 years.