Short-Term Aquatic Animals

This is about animals, which specially utilise stretches of water that appear only for a short period of time. These organisms, which exist in areas where one does not expect aquatic inhabitants, are particularly impressive.

A Stranded Mosquito...

In Central Europe, short-term waters like flood areas or waters from melted snow are the origin of plagues of mosquitoes. The eggs of these mosquitoes wait on dry land for months - sometimes even years, and as soon as they sense that they are in water, they start to develop.

Small Shrimp in the Riverside Forest Biotope

In the past, you could often find small shrimp, which also develop from eggs lying on the dry, romping about in riverside forests. Besides others, water fleas (up to 28 mm in size), left picture, and fairy shrimp (up to 50 mm) belong to these types of shrimp. Both species had formed communities together until the day too much of their stretch of water was drained or polluted.

These shrimp mainly feed on animal food, which means that other organisms have to be present in these short-lived waters and use them as their habitat.

The Tough Struggle for Survival

But also in very dry regions like the deserts of southern North America, instantaneous development of masses of shrimp related to the ones described above, were observed. After 14 days in the new stretch of water, the animals are already fully developed, and the next generation of eggs will hold out in the dry until the next rainy season. Maybe they will even be blown away by the wind.

This is a very impressive example of the struggle for survival: To be threatened with drying out for two weeks only to wait for years, sometimes even decades or centuries, until the next generation sees the light of day, and thus the tough two-weekly struggle.