Existence of blue-green algae confirmed in Grand Lake water toxicity test
Francis Campbell in saltwire.com June 15, 2021
“Blue-green algae has returned as the main suspect in the Grand Lake water contamination saga…Tri Nguyen-Quang, an agriculture engineering professor at the Dalhousie University agriculture campus, said he was also at Grand Lake and the smaller Fish Lake on Friday afternoon to take water samples. “I can confirm that there is no sign of algal blooms in Fish Lake and Grand Lake,” Nguyen-Quang, an authority on algae blooms, said earlier about the toxin problem identified at what is known as Shubenacadie Grand Lake, a large body of water that straddles the municipalities of Halifax and East Hants…Even if there were cyanotoxins last Wednesday — according to a picture of vast blooms in Grand Lake on June 9 — they certainly dispersed and disappeared at the moment I came there,” he said…Towers said there can be difficulties with water sampling. “Water as you know is moving, it’s diluting things, so (it’s) where you take the sample, how you take the sample and part of the confirmation we have is from an actual mat of the bloom itself, as opposed to the water sample,” Towers said. “The straight water sample couldn’t detect anything above the criteria limit but the sample taken from association with the plant mat, the algae mat, showed a result.”…Nguyen-Quang said two different test results are possible, “depending on what samples and where they (department) used to test and what method.” He had said in the past that the water in a lake is rendered toxic and undrinkable when it becomes too rich in nutrients…A woman who lives near the portion of Grand Lake where the dogs and their owner came in contact with the lake water told The Chronicle Herald last week that it is not unusual to find dead fish in the passage stream that connects the larger Grand Lake with the smaller Fish Lake. “All through our yards,” she said of where the dead fish end up. “The birds take them, the foxes them and bury them, and dogs eat them.” She said the dead fish are often attributed to the migrating stream being too shallow…Nguyen-Quang said harmful algal blooms (HAB) have been identified periodically over the past five years every summer, when the weather is warmer, and depending on the water body — lakes, ponds or reservoirs. The blooms can develop from June until late October or November. “The only natural way to deal with them is to control the waste rejecting to the watershed,” which can increase the “eutrophication” or proliferation of nutrients in a lake, he said. Nguyen-Quang said there are many other artificial solutions suggested to mitigate algal blooms but he questioned their sustainability.
Expert says blue-green algae may not be cause of Grand Lake contamination
CBC News · Posted: Jun 14, 2021 “A Dalhousie University professor does not think blue-green algae is to blame for the contamination at Grand Lake, N.S., which led to the deaths of two dogs and sent a person to hospital last week…Nguyen-Quang tested the water after gathering samples June 11 between 4 p.m. and 5 p.m., and determined there was no evidence for cyanobacteria or the toxins they produce. Blue-green algae is caused by cyanobacteria. The professor said he didn’t see any visible algae blooms during his visit. However, Nguyen-Quang said he spotted fish, including many that appeared to be in poor health, moving en masse into Grand Lake from nearby Fish Lake. Some appeared to be dying.”Under my point of view in ecology, there would be some problem there in the lake, Fish Lake,” said Nguyen-Quang, who teaches at Dalhousie’s Agricultural Campus in Truro. He added that could explain why fish were migrating so quickly into Grand Lake.
Nova Scotia veterinarian warns dog owners about toxic blue-green algae in lakes
Jun 13, 2021 3:00 PM By: Canadian Press. in Halifax Today “Dog owners in Nova Scotia should be on the lookout for blue-green algae in lakes and ponds this summer after two dogs died following a potential exposure to the bacteria”
(Shubenacadie) Grand Lake, Wellington
Deep station total phosphorus (TP)- comparison with our hindcast models; October 18, 2013
Phosphorus:- Details on LCC (Lake Carrying Capacity)/Threshold values of lakes, and comparison with artificially high values chosen by the HRM; March 14, 2014