Biodiversity

Biodiversity is a term that represents the variety of life. Biodiversity is calculated by measuring the number of different species in a defined area as well as the species composition and distribution.

An ecosystem with many different species is a healthy ecosystem, where each species plays a role in an overarching structure. Such an ecosystem contributes to stabilizing the climate, ensuring clean air and water, and thereby further supporting a rich animal and plant life. These contributions from the natural world are known as "ecosystem services", and if the ecosystem's biodiversity is depleted or species go extinct, ecosystem services are also lost.

Between 50-80% of the planet's oxygen comes from photosynthetic marine organisms (NOAA). The ocean also plays a crucial role in the water cycle and in stabilizing the climate through carbon sequestration. Furthermore, mangroves and kelp forests protect coastlines from storms and erosion.

The ocean is essential to Earth's balance, and its biodiversity plays a crucial role in ensuring resilience and adaptability to environmental changes.

There are many threats to marine biodiversity. In general, nutrient discharge poses the greatest risk, along with climate change. Fishing, and to a lesser extent invasive species, also have a negative impact on biodiversity overall. Resource extraction, shipping, pollutants, and maritime constructions can further affect biodiversity in parts of Danish waters.

We depend on high biodiversity. If organisms continue to disappear from ecosystems at the current rate due to habitat loss and degradation, pollution, and unsustainable exploitation of nature, ecosystems could collapse.

It is therefore crucial to restore and safeguard high biodiversity, not least in Denmark's marine environments, within habitats such as eelgrass meadows, stone reefs, and mussel beds. Nutrient inputs must be reduced alongside stronger protections in larger areas, such as a halt to fishing and restoration of lost habitats.

One of these lost habitats is stone reefs, which are particularly important because they provide a foundation for rich animal and plant life. Apart from the life that attaches directly to the stones, reefs also serve as habitats for many free-living animals such as starfish, fish, and crabs.

Biogenic reefs, such as mussel and oyster beds, are found in shallower waters in Danish fjords. These reefs also create essential living conditions for other species, and the mussels are a vital food source for waterbirds.

Eelgrass forms dense meadows that host rich animal life, including crabs, snails, mussels, and fish, and it serves as an important nursery for juvenile fish. Eelgrass is also an important food source for many marine birds, thereby enhancing the biodiversity of coastal areas.

Salt marshes and coastal meadows also contribute to increased biodiversity by serving as habitats and feeding grounds for a wide variety of wading and migratory birds, invertebrates, and fish. Establishing new salt marshes and coastal meadows on, for example, farmland can increase biodiversity by improving living conditions for a wide range of plants and animals.