#Preventing #Algae #Blooms An excerpt from an article by Rex Weyler in Watershed Sentinel A lake is not a thing; it is a process. A lake is a dynamic living system, a flow of energy and nutrients, a home for its inhabitants, always evolving, forever shifting moods. I live on the shore of Hague Lake on Cortes Island, BC and I watch it change daily, ethereal with silver light one moment, then suddenly menacing and dark, then smooth like glass, until a trout hits the surface and sends a ripple out in every direction. This past spring, the lake exhibited some new and disturbing behaviour. In April, our community experienced an unpleasant smell and taste in the lake water. For days, no trout hit the surface. I paddled out in the canoe and ran my fingers through a dense algae bloom. A biologist friend and I collected water samples, looked at droplets under our microscopes, and began to identify the organisms living in our lake. Inside a tiny drop of water, pressed flat between two pieces of glass, exists an entire world, in which bacteria, diatoms, dinoflagellates, and copopods swim around like alien sea monsters in the mid-Pacific. We found Volvox algae, which is non-toxic, and a cyano-bacteria, Nostoc sp., which is toxic and can kill other lake species. We found Spirogyra curling like fusilli pasta and little star-shaped Asterionella. Most of these organisms are common in lakes, but the extent of the algae bloom indicated a lake going through an ecological transition. The blooms of Volvox and Nostoc suggested that our lake was processing an increased load of nutrients, typically phosphates and nitrates, which flow from human settlements and non-human sources. The annoying smell and taste indicated low-oxygen conditions caused by a large volume of decaying organisms, fed by excess nitrogen. Among the nine most critical global ecological crisis or “planetary boundaries” as described by 28 international earth scientists, the nitrogen cycle is the second most out-of balance (after species diversity loss). Suddenly, our community felt compelled to learn more about lake ecology. One of the first things we learned is that similar fresh water crises play out globally in virtually every inhabited watershed on Earth. Peak Water Repeated algae blooms can kill lakes or transform them to swamp conditions. Algae blooms virtually killed Lake Erie, between Canada and the US, and likewise Green Lake in Washington State, Fern Ridge Lake in Oregon, Lough Neagh in the UK, Lake Taihu in China, and so forth around the world: thousands of dead or swampy former lakes. Fresh water is a precious resource. Only about three-thousandths, 0.3%, of all fresh water on Earth exists in lakes and rivers; 30% exists in ground water; and 70% remains locked in ice. Today, over a billion people have no access to clean, fresh water. In wealthy nations, consumers unwittingly use massive water resources, such as the 650 gallons necessary to produce a cotton t-shirt, or the 139 gallons required to prepare a single 16-ounce cup of fancy logo coffee. North Americans use some 100 gallons of water per person each day, while in Chad and Niger, the average person uses as little as one gallon, and feels fortunate if that water is clean and safe. Industrial projects such as the Canadian tar sands, shale oil fracking, and pesticide-based agriculture pollute water tables, rivers, and lakes. About half the world’s fresh water is polluted. Meanwhile, increasing global temperatures transform water to vapour at a faster rate, drying lakes and aggravating the water crisis. The Aral Sea, in Kazakhstan, drained for cotton production, has dropped 16 metres and shrunk in size by 70%. Lake Chad in Africa has dropped 10 metres and lost 95% of its area, as regional governments fight over the remnants. The giant Ogallala Aquifer, the main source of crop irrigation in the western US, is now dry in some regions, and would take tens of thousands of years to replenish by natural rain cycles. Around the world, hotter global temperatures increase droughts, while the world’s human population consumes fresh water faster than Earth’s natural hydrological systems can replenish it. Some regions have already reached what Lester Brown identifies as “peak water.” The Capitalist Solution: Sell It! In 2008, Credit Suisse advised clients of a booming investment opportunity, the “depletion of freshwater reserves [due to] pollution, disappearance of glaciers, and population growth.” They advised: “One way to take advantage of this trend is to invest in companies geared to water generation.” Companies, of course, do not actually “generate” water, but merely lay claim to it. “Water is the oil of the 21st century,” DOW Chemical CEO Andrew Liveris said in 2008. Water is now a $425 billion annual industry. Five food and beverage giants – Nestlé, Unilever, Coca-Cola, Anheuser Busch, and Danone – consume almost 575 billion litres of water per year. Typically, the industrial solution makes the core problem worse. A single litre of bottled water requires 3 litres of water to produce and leaves a trail of plastic throughout the world. “Water,” said Citigroup economist Willem Buiter in 2011, “will become … the single most important physical-commodity.” Among the profitable uses of water, Citigroup includes hydraulic fracking. A typical fracked oil well requires 4 million gallons of water. Fracking companies now outbid farmers – and thirsty communities – for water rights. Preserving Earth’s Water In our neighbourhood, the algae bloom alerted us to collect data and begin the long process of mitigating and reversing our impact on the lake. We have begun a series of tests to measure lake conditions, nutrient levels, fecal counts, and algae cycles. The primary human contribution to lake algae blooms are nutrients — nitrogen and phosphate — from our septic, gray water, animals, and detergents. The immediate actions that a community can take include: 1. Reduce the use of phosphate soaps. 2. Eliminate toxins (paint, varnishes, pesticides, photographic chemicals, from home drainage. 3. Avoid inorganic fertilizers, which contain nitrates. 4. Upgrade septic systems, pump your septic, and clean and maintain it regularly. 5. Isolate animal manure from run-off, and compost manure well before spreading on gardens. 6. Avoid logging or clearing lake shores and replant disturbed lakeshore. 7. Place bio-remediation fields below septic or farm fields. Some residents in the Cortes Hague and Gunflint lakes watershed have initiated a “myco-remediation” project based on the successful research of Paul Stamets and his colleagues at Fungi Perfecti. Certain mycelium species, particularly Stropharia rugoso annulata, the popular and tasty Garden Giant mushrooms, have an appetite for the very compounds we want to isolate from our lake, the nitrates, phosphates, bacteria, and other organic debris. Stamets donated Stropharia spawn to get us started. The spawn incubates in wood chips, and in the spring, we will spread the mycelium and wood chips into beds, about a foot deep, below septic and animal fields. The mycelium metabolizes the nutrients, bacteria, and toxins that can cause problems in the lake. This fall, in the early mornings, cutthroat trout, once again, hit the lake surface, and this feels like a good sign. The rains have added almost a metre to the lake level. The wind has picked up now, and little whitecaps break in the grey expanse of water. The trout have gone back to their cool holes. Two Horned Grebes have taken shelter here from the southeaster. The lake is our teacher now. Our role is to watch and learn. watershedsentinel.ca/content/preventing-algae-blooms
Posted on: Fri, 02 Jan 2015 02:30:22 +0000
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