2014-07-18: As most can attest visually, we have experienced another large die off of blue-green algae in the last week, but notably the lake is already being repopulated with another potentially more toxic species and thus caution is still advised. Fortunately as of samples taken as recent as Friday, July 18, 2014 the toxin levels lake were low through much of the lake and only moderate in a couple of sites along the shoreline. However this can change rapidly as the bloom changes, week to week, day to day, sometimes hour to hour.
So far this year we have had an Anabaena bloom (Jan-Apr) followed by a clear period until early June when a smaller Microcystis bloom began. Within a few weeks the Microcystis was supplanted by a Gloeotrichria bloom which we have experienced until the last few days. This bloom however is being replaced by another Microcystis bloom as the cycle of boom and bust continues.
Nutrients in the lake and sunlight fuel these blooms which have been increasing in frequency and duration since the 1960's and particularly since the early 1990's (See Sediment Core data in the Bathymetry & Paleolimnology Study by Eilers et al 2005). Reducing the nutrients from the lake and watershed is a critical step in reducing these recurring Harmful Algal Blooms (HABs).
2014-07-10: Wind and wave action has moved the blue-green algae south for the most part away from Neotsu, and to a lesser degree Sand Point. Observations suggest that the greatest concentrations are along the eastern shore of East Devils Lake State Park, but are certainly present in varying degrees lake wide. No toxin data were collected for this week as this is an alternating schedule. Notably though the type of blue-green algae has not changed, nor have the assumed concentrations over the lake as a whole, only the distribution which again is largely controlled by the wind. Last week all samples for toxins were below 10ppb, and estimated to be even below 5ppb. However given the uncertainty with blue-green algae caution is advised when any significant bloom exists in the lake.
2014-07-02: Toxin monitoring showed that at all lake sample sites, levels were all below the Recreational Water quality standard of 10ppb for Microcystin, and estimated to be even below 5ppb as shown. However a major bloom is present in the lake as indicated by the Observations - Cell Counts. The big wind event last week moved most of the Harmful Algal Bloom (mostly now dominated by the species Gloeotrichia echinulata which is only a weak toxin producer largely explaining the low toxicity) to the north end of the lake. As such moderate to high concentrations were found in all areas north of and including Regatta Grounds. The south end of the lake had concentration that were all low, again due to the large wind event last week from the southwest. Wind and wave conditions change and can move these free-floating organisms around readily, so always look before you leap. Also while the toxin levels at all sites were low, this can change quickly depending on species and conditions, and other toxins not tested may be present.
2014-06-27: The big wind and rain events of the last 24 hours the Harmful Algal Bloom are nearly completing mixed throughout the lake. As the winds die back look for the blue-green algae returning to the surface which may form scums. As a result a lake-wide Yellow Caution is being shown. As always, keep pets and children away from any scummy waters. Toxin monitoring resumes next week.
2014-06-20: Based on the decreasing clarity in parts of the lake, the District conducted some toxin monitoring this week as shown. Shoreline samples with higher concentrations of blue-green algae had higher toxin values, but all were below state standards for recreational water. Conditions can change rapidly, so always Look Before you Leap!
2014-06-13: As the summer season progresses we have seen an increase in blue-green algae in parts of the lake. Specifically the campground was exhibiting a presence of such a bloom. All other areas along the shoreline were low or had no detectable blooms. As a result we are still in the period where we are just making observations as opposed to actual toxin testings. Conditions can change readily, so always Look Before you Leap!
2014-06-05: The lake continues to show signs of a blue-green algae bloom in much of the water column. Wind blows these free-floating organisms around, so variation in densities around the lake is expected and is the typical norm. Clarity continues to be good though suggesting there are only low concentrations at any of the sample sites around the lake.
Conditions can certainly change fast though, so always look before you leap. Notably, the Oregon Health Authority already reports Lost Creek Lake in SW Oregon has a major bloom, one that started a few weeks earlier than their first bloom last year. Of further interest their second bloom was a fall/winter bloom lasting 109 days, showing the unpredictability of these Harmful Algal Blooms. Also Mussel Harvesting has been closed from the Columbia River to Newport, indicative of similar types of blooms, but in this case obviously out in the ocean. Variations in weather conditions can cause significant change in how these microorganisms photosynthesize and reproduce, which is further impacted by the changing climate we live in, making predictions about Harmful Algal Blooms more and more complex.
What we do know is that Harmful Algal Blooms prefer slow moving, stagnant water. The longer they are in the water column the better they compete as they are slower to reproduce than "Good" algae. Impounding water both stagnates the water and increases the residence time of the lake which thus favors these Blue-green algae over "Good" algae.
2014-05-21: We are beginning to see the initial signs of a blue-green algae resurgence. Microcystin (one type of Blue-green algae) has been seen throughout much of the lake, however visual indications suggest it to be at a rather low concentration at this time. This however can change quickly, literally in a manner of days as populations can increase rapidly with increased sunshine and thus photosynthesis.
2014-04-17: No toxins found in Mid lake sample analyzed by King County Environmental Lab or in shoreline samples analyzed today.
2014-04-15: The water quality of Devils Lake has made tremendous improvements in the last few days. The Harmful Algal Bloom which turned the lake shades of gray, blue-gray, green, blue-green, and even white only a week ago has crashed throughout much of the lake. Much of the lake you can see right to the bottom with clarity upwards of 8'.
The bloom that we did have was dominated by a type of Anabaena, which was as of Friday all but non-existent in the mid lake sample we had analyzed. The improvements are seemingly continuing as the clarity increased from basically 3 feet on Friday to over 8 feet for the entire south half of the lake as reported Monday. The north half of the lake was still blue-green as of last report, so there is still recovery to be had, but the scums have dissipated which shows recovery is happening. Dissolved oxygen has also rebounded considerably, but lags behind in the both arms of the lake to the north.
Blue Green Algae Cell Counts: Total Blue green algae = 115 cells/ml (Alert thresholds are 40,000 and 100,000 depending on species). The number of blue-green algae were determined from a Friday sample and are shown here in total. The alert level is 100,000 for Anabaena and its cousins, so we are nearly 1000 times less than that now.
Toxicity: Samples for the four types of toxins commonly produced by Anabaena are currently being analyzed by King County Environmental Lab, and will be made available as soon as possible. Typically toxins can linger well after a bloom crashes, so while the lake may look clear there still may be toxins present.