Now you can venture to the edge of the pond. Is it still, a light brown, clear enough to see through it for about a foot away? Or is it covered with a thin film of green close to shore, bubbling to any response in its movement? For the first 7 weeks, the pond was brown or reflective; it seemed relatively clean. For the last few weeks, when the sun emerged, rain subsided, and warmer temperatures reminded us it was spring, the green film developed. This is pond algae.
Pond Algae
Algae are simple, primitive plants that can float freely in water. They reproduce through spores, and reproduce extremely quickly.
The algae seems to stick around with the stagnation of the pond. On one day with heavy bird activity, the middle of the pond was kept moving, and the area stayed clean, while closer to the bank, the water was still. Tossing a stick into the muck disturbed the algae and produced large slimy bubbles. I noticed a trail of such bubbles, and deduced that some brave bird must have recently swum through the muck, leaving a trail behind.
Pond Algae catching Black Cottonwood tree cotton
Runoff filled with fertilizers makes its way into ponds, and ironically damages the ecosystem. The increase in nutrients fosters algae so much that it begins to choke out other species. When it decomposes, it sinks to the bottom, creating a space consuming sludge, and sucks up oxygen and kills fish. With no more fish, birds will soon have to leave to find other sources of food. Even though UBNA is a natural restoration area, it’s water is subject to fluxes in quality. (4)
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