A novel mechanism for freshwater reef growth?

Abstract

Exploration of a new habitat with distinctly reef‐like features in South Fishtail Bay of Douglas Lake, Michigan has led to the development of a series of hypotheses regarding the formation of magnetic, tubular features known as cups that are found at the site. The age of the habitat and whether or not the cups are still growing is unknown, but it is nevertheless clear from this project that the cups are distinctive microhabitats. Analysis has shown that the cups contain more organic matter than the surrounding hard substrate, but equivalent amounts of chlorophyll α. The unique chemical and structural composition of the cups could be a product of bacterial activity. Algae and groundwater may also be playing a role in creating altered local conditions at the habitat that contribute to the formation of the cups.