hapetusmatto

Hapetusmatto, often translated as "oxygen mat" or "oxygen carpet," is a term used in marine biology and ecology to describe a dense layer of cyanobacteria and other microorganisms that can form on submerged surfaces in aquatic environments. These mats are typically found in shallow, nutrient-rich waters, such as estuaries, salt marshes, and intertidal zones. The primary characteristic of a hapetusmatto is its ability to perform oxygenic photosynthesis, producing oxygen during daylight hours. This oxygen production can create localized oxygen-rich microenvironments within the mat.

The composition of a hapetusmatto can vary but commonly includes species of cyanobacteria like Microcoleus and Lyngbya, alongside diatoms and other algae. These microorganisms secrete a sticky extracellular polymeric substance (EPS) which helps bind them together, forming a cohesive mat structure. This EPS also plays a role in trapping sediment and nutrients, further contributing to the mat's development.

During the day, the photosynthetic activity within the hapetusmatto leads to a significant increase in dissolved oxygen levels, sometimes creating supersaturated conditions. However, at night, or when light is limited, these microorganisms respire, consuming oxygen. In very dense mats, this respiration can lead to a depletion of oxygen, creating anoxic or hypoxic conditions beneath the surface layer. This daily fluctuation in oxygen concentration can have important implications for the surrounding benthic communities, influencing the distribution and survival of other organisms. Hapetusmatot are important primary producers and contribute to nutrient cycling in their ecosystems.