An online resource based on the award-winning nature guide

Algae

Watershield Flowering

7-29-15  watershield 008Watershield is a perennial aquatic plant whose bright green, shield-shaped leaves float on the surface of shallow water in lakes and beaver ponds. Its small purple flowers bloom from June through September, with each individual flower only lasting two days. One the first day, the female flower parts (stigma, style, ovary) are mature. After receding into the water overnight, the flower re-emerges with mature male flower parts (stamens, filaments, anthers). The anthers burst open, releasing pollen to the wind, and the flower is then withdrawn below the water where the fruit develops.

The horizontal rhizomes, or stems, of Watershield, as well as the undersides of the leaves and developing buds, are covered with a thick, jelly-like slime. Botanists theorize that it may deter snails from grazing on these plants. Watershield secretes a number of chemicals that kill or inhibit growth of a wide range of bacteria, algae, and other plants.

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Snowfleas Appearing

snowfleas 049A7533One rarely even thinks about snowfleas (a species of springtail, Hypogastrura nivicola) until snow falls and then starts to melt. This is when these tiny wingless arthropods that catapult themselves through the air with the aid of a fork-like structure, or furcular, seem to magically appear out of nowhere. They actually are present year round, but their dark color makes them visible against the white snow.

The great majority of snowfleas live in soil, feeding on fungi, algae, decaying plant matter and bacteria. They work their way to the surface of the snow, crawling up the trunks of trees, plant stems and side of rocks where an open channel allows their migration. Thousands can be found on melting snow, especially in tracks or other depressions. No-one is absolutely sure of why they exhibit this behavior, though some scientists feel that these migrations are triggered by overcrowding and lack of food. Eventually those that survive on top of the snow make a return trip down into the soil.

Formerly classified as insects, snowfleas are now categorized as hexapods, due to some features they have which insects do not.

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Why Many Lichens Are So Green After It Rains

12-4-12 wet lichen IMG_6171Have you ever noticed that the color of some lichens is a more intense green after they get wet? There’s a very good explanation for this phenomenon. Lichens are made up of an alga or cyanobacterium and a fungus. The alga or cyanobacterium makes the food, and the fungus absorbs the water. A typical lichen has a three-layered structure. A middle layer containing algal cells entwined in threadlike fungus fibers called hyphae is sandwiched between two layers of fungal tissue. Lichens that turn bright green after it rains contain green algae which contains chlorophyll, a green pigment. When it rains, the fungus (which surrounds the algae) soaks up water like a sponge, causing the fungus to become more transparent, which allows the green pigment of the algae to be seen more clearly.