Phytoplankton Stage - Hydrarch
In this initial stage, the pond water is poor in nutrients and is devoid of much life. At this stage, the water is incapable of supporting larger life forms. So, in such situations, phytoplanktons consisting of microscopic algae, begin to multiply and they quickly become the pioneer colonisers. As the phytoplanktons and the dependent animal population dies, decomposer organisms like bacteria and fungi increase in number and bring about decomposition of the organic material.
Decomposition results in the release of minerals and enrichment of aquatic habitats. Besides this, some silt may be brought to the pond, by the rain water from the surrounding land. By now the pond becomes shallower, and the mud at its bottom is rich in nutrients. Now it can support some rooted hydrophytes, thus initiating the next stage.