Tag Archives: Algae bloom

Hood Canal changes color again, thanks to plankton bloom

Hood Canal has changed colors again, shifting to shades of bimini green, as it did in 2016, when satellite photos showed the canal standing out starkly among all other waters in the Northwest.

Hood Canal has changed colors as a result of a plankton bloom, as shown in this aerial photo taken in Northern Hood Canal.
Photo: Eyes Over Puget Sound, Washington Ecology

The color change is caused by a bloom of a specific type of plankton called a coccolithophore, which shows up in nutrient-poor waters. The single-celled organism produces shells made of calcite, which reflect light to produce the unusual color.

Observers are now waiting for the clouds to depart, so we can get new satellite images of the green waters.

The plankton bloom started June 1 in Quilcene and Dabob bays, according to Teri King of Washington Sea Grant. It came about a week earlier than last year and has since spread through Hood Canal. Observers in the Seabeck area reported seeing the bloom the past few days. The bimini green color, which gets its name from an island in the Bahamas, is especially noticeable when the sun comes out.

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Phosphate ban offers a bit of help to ailing lakes

New formulations of dishwasher detergents will help reduce the amount of phosphorus getting into lakes and streams throughout the United States. As of Thursday, detergents containing more than 0.5 percent phosphorus by weight will be banned in Washington and 15 other states, as I reported in a story in yesterday’s Kitsap Sun.

If you don’t live on a lake and never go swimming or boating in a lake, this may seem like a needless effort. But when you see excessive algae blooms and plant growth in a lake, there’s a good chance that it is related to the amount of phosphate flowing into the lake.

It is interesting that this phosphate issue comes up in the same month that I have been writing about new state and federal permits to bring pesticides into compliance with the Clean Water Act. See Water Ways, June 9. Under current state permits, it is fairly easy to get approval to kill the weeds in your lake. But this does nothing to remove the phosphorus that feeds the plants, if that is what is promoting the weed growth. See the Environmental Protection Agency’s website on nitrogen and phosphorus pollution.

Phosphates in laundry detergents were essentially banned in 1994 in Washington state. On Thursday, the ban is extended to dishwasher detergents. That still leaves what is generally the largest source of phosphates to our water bodies: fertilizers from lawns — and especially from farms in some locations.

Do people who live near lakes make the connection that their green lawns may be contributing to their green lakes?

This is an old story in Michigan and Wisconsin, where people have been struggling for decades to keep their lakes healthy. In 2004, Dane County, WI, took the bold step of banning phosphates in fertilizers, following research that showed that most soils in the region already had adequate phosphorus for plant growth. Now, unless a soil test confirms the lack of phosphorus, it is illegal for county residents to apply fertilizer containing phosphate. See Phosphorus Control in Dane County.

I’m not sure if this ban on phosphate fertilizers is an option anywhere in Washington state, but people probably could use low-phosphate fertilizers, especially near lakes, or at least they could conduct soil tests to see what nutrients need to be added.

Another option is to reduce or eliminate your lawn, switching to native plants that thrive in natural soils found in the region.

I find it interesting that some people are now calling on residents who live in the vast watershed of the Mississippi River to eliminate their lawns as a result of the oil spill in the Gulf. Check out “Want to Help the Gulf of Mexico? Kill Your Lawn” by the Ocean Doctor.

Here’s the argument: The Gulf already suffers from a low-oxygen problem blamed on fertilizers coming from farms and homes throughout 40 percent of the continental United States. Methane gas being released from the BP blowout is fertilizing the plankton that contribute to the low-oxygen problem. The risk is high that many fish and other creatures will be killed as a result of a massive dead zone likely to be created. Since nobody seems able to stop the gushing oil, people may reduce the damage by eliminating their use of fertilizers.

I’m not sure if this makes sense, just as I’m not sure if the use of phosphate-free dishwashing detergents will make much difference. Researchers should be able to help us with these calculations. But if we can live without excessive phosphates — nitrogen, too, in the case of the ailing Hood Canal and South Puget Sound — then maybe it’s worth a try.