Those nasty algae blooms
It clings to fishing line, discolors boats, smells, clogs intakes, depletes oxygen and sometimes kills. It is blue-green algae, one of the most common forms of the pesky organisms found in North Dakota rivers, lakes and reservoirs.
Algae blooms are ugly and unsightly. They can be dangerous too, especially blue-green algae. Pets and livestock that drink blue-green algae contaminated water risk death.
“The potential is there to cause serious harm,” said Heather Husband, North Dakota Department of Health, Division of Water Quality. “It is hard always to tell, but the cyan-colored algae can be toxic.”
Husband is stationed in Towner, not far from the Souris River. She is the United States co-chair for the International Souris River Board Aquatic Ecosystem Health Committee. One of her duties is to evaluate water samples drawn from the Souris. During a Wednesday meeting of the ISRB in Minot, Husband revealed that water samples from the Souris River once again tested significantly higher than Water Quality Objectives established for phosphorus.
“No big surprise,” said Husband.
All eight samples collected in 2013 exceeded the minimum guidelines of 0.10 milligrams per liter. The amount of phosphorus in the set of Souris River samples ranged from 0.15 to 0.33 milligrams per liter, more than three times the objective level. It is a pattern that has continued for several years without any significant change.
“Absolutely it’s a concern,” said Husband. “We do care. People in North Dakota are more connected to the land than in other places. They fish, boat, recreate. It is part of our history. Families spend time at the water and, the place you spend time, you want that to be enjoyable.”
Enjoying time on the water becomes seriously compromised when algae blooms, fueled by high levels of phosphorus, sometimes cover an entire water body with growing organisms. It is aesthetically unappealing. Generally the fish bite slows considerably due to limited visibility in algae infected water. Boats and fishing equipment become coated with algae. Intakes can become clogged. Swimming stops, too.
“You not only have how it looks and smells, but another issue you have is that an algae mat limits light penetration. Plants at the bottom of the aquatic environment become stunted and are unable to grow,” said Husband. “Eventually the algae will die. The decomposition process uses oxygen which can lead to summer fish kills.”
Scott Elstad is the aquatic habitat supervisor for the North Dakota Game and Fish Department. He says there are about a dozen forms of algae in state waters, but believes blue-green algae has become more dominant in recent years.
“For the most part they aren’t toxic,” said Elstad when asked about algae outbreaks at many lakes in the state. “There are many species of blue-green algae, the stringy stuff that grows on rocks and docks and so forth. It’s not toxic as long as it is alive. It goes in cycles. It grows three weeks or so and dies off. That’s when it releases toxins into the water. A small amount on a large lake will be diluted out for the most part.”
“Blue-green algae is actually a bacteria. You don’t want to ingest it. It’s a public health risk,” added Scott Gangle, NDG&F Fisheries Management Section leader.
Phosphorus can occur naturally, but the main source is of phosphorus in North Dakota waters is generally attributed to fertilizers such as those used on lawns and farm fields. Eventually rain and runoff will carry phosphorus into a river, lake or reservoir where it causes algae to flourish.
“When nutrients get in there the algae takes hold of it and puts it to use,” explained Husband. “Phosphorus is one of the things you find commonly in fertilizer, along with nitrogen. Those are the big ones that relate to algae. That’s kind of the basis of it. Phosphorus attaches to soil particles so it’s a little more trackable. It is what we track because it is easy to track.”
Fertilizer is not the only source of phosphorus that can make its way into North Dakota water. Animal and pet waste and leaking septic systems are among other sources that can contribute too. No matter the source, excess phosphorus usually leads to an aggressive algae bloom that the severely diminishes water quality for those that utilize the resource.
Although data is incomplete, it is thought that algae blooms in state water have increased substantially in the past 50 to 100 years.
“To some extent, yes, that happened,” said Husband. “The Earth works on a much larger time scale than human beings. The question is, did it happen at the same rate and extent as people came along and began influencing things?”
A number of agencies have voluntary programs designed to help landowners and ranchers combat excess, nutrient runoff into watersheds. The State Health Department awarded $2.8 million to projects to improve water quality in 2013-14. According to Husband, all seven watershed projects were in the eastern half of the state. None were along the Souris River.
“Game and Fish, the Health Department, FFA, all have programs to try and have the best management practices,” said Elstad. “All are voluntary. The key is to filter that water before it gets to water bodies, such as through CRP or grasslands.”
While some small lakes might see benefits from runoff improvement projects within a few months or years, a larger body of water like Lake Darling may take many years before results become evident. Nevertheless, says Husband, every project has to start somewhere.
“Everybody is concerned and doesn’t want it to happen, but it seems like such a huge problem. What can one person do?” said Husband. “We need to get the message out a little better that will multiply the beneficial effects of good water quality in general throughout the state.”