Usually, filamentous algae first becomes noticeable in ponds and wetlands in mid-April. This year? The second week of March. And it's thick, too. But algae isn't just a plant. Filamentous algae, strands of one celled plants that receive their energy from the sun and the water simultaneously, are the basis of an entire food web and ecosystem. However, unlike ecosystems dominated by soil and aquatic fungi or bacteria, an algae-dominated system is a volatile, temporary system that can act unpredictably and have fast-acting, far-ranging impacts.
The algae itself isn't the problem. Algae, like all plants, inhale CO2 and exhale O2. That's a good thing. The problem is that the algae begin to reproduce very rapidly as soon they can sense that excess pollutants are available in the ecosystem. In the case of stormwater ponds and most of the east coast's rivers and creeks, the algae are often right, as rainstorms bring in lawn and farm fertilizer, livestock manure, wildlife and pet waste, and even septic system effluent. But as the immediate pollution source (the algae food) is depleted, the algae begin to die. And that's a problem.
The primary decomposers of filamentous algae are about a dozen species of aerobic bacteria. The more algae they have to eat, the more oxygen they inhale and the more they reproduce - giving rise to more oxygen-stealing bacteria. What's left after just a few weeks is often a low oxygen (hypoxic) or unoxygenated (anoxic) zone in a pond, creek or river. Do you live in a place where every year there's a fish kill sometime in May or June? Well now you know why! Fish swim into these low oxygen zones, don't know how to get out, and quickly die. Due to filamentous algae's main growth season (early spring), its die-off often occurs right when fish spawns/migrations are peaking in small, polluted rivers and creeks. Perfect recipe for fish kills.
|This filamentous bloom on the Little Patuxent River is peaking about 6-7 weeks early in 2012.|
|The white beetle spin is usually killer in early spring.|
On this day, it just killed some algae and whatever else
lives on the algae.
At this point it's so warm that I really feel like there's no killing this stuff, no watering it down with nor'easters. It's going to take its toll. Will it make the national news? Hard to tell. A few predictions, though:
Fish kills will be above average to record highs. This has a lot to do with luck and timing at this point.
Beach closures along the interior waterways (Chesapeake Bay tributaries, Delaware Bay tributaries, lakes and ponds) will be at record highs. As soon as this first algae bloom dies, I'd bet that bacteria counts will start to exceed the EPA "safe beach" limits up and down the coast. Notice I didn't mention ocean beaches - that's a whole 'nother ball of wax.
Water clarity will be at or near record lows for the months of March - July (August brings "hurricanes" into the equation, which can tend to muddy up the water a bit).
So hang on to your hats. And check the water quality report before you go water skiing, swimming, or anything else fun in east coast waters this summer!