Threatened Species

The IUCN Red List of Threatened Species is available online for research free of charge: https://www.iucnredlist.org/.

The 2019 global IPBES report estimates that there are approximately eight million animal and plant species worldwide. Around one million of these are threatened with extinction – many within the coming decades, unless the drivers of biodiversity loss are significantly reduced [Sources 1-3].

To this day, humanity knows too little about biodiversity and the ecological relationships of this planet. Nevertheless, we are relentlessly destroying the habitat of millions of animals and plants. What humans can see of this destruction with their own eyes above water, and for the most part still fail to change, is lost entirely below sea level. What we do not see remains hidden from us, and so humanity continues to ruthlessly exploit the ocean.

The core of the problem: while we still do not comprehend many ecological relationships on land, the ocean ecosystem is even more complex. Living organisms complement one another; every single organism, no matter how small, has its vital place and, if lost, could impact or even collapse this fragile ecosystem.

Biodiversity

Biodiversity, or biological diversity, is structured into three broad levels and is critical for the capacity to adapt to changing environmental conditions [Source 1]. The interplay between these individual levels enables the continuation of life. Nevertheless, and despite existing conservation measures, our planet's biodiversity is under threat.

When thinking of "biological diversity", most people probably first think of species extinction. This is, of course, closely linked, but there is more to it: the diversity of ecosystems, of species, and of their genetic material.

Genetic diversity arises, among other factors, through mutations and recombination, and can be influenced by the exchange of genes between populations. It provides the raw material upon which natural selection can act and is therefore an essential prerequisite for the evolutionary adaptability of populations. Small populations frequently lose genetic diversity due to genetic drift and are at greater risk of inbreeding. The decisive factor here is not solely the number of existing individuals, but the so-called effective population size, which, in simple terms, describes how many individuals actually contribute to the genetic diversity of the next generation. How large such a population ultimately needs to be can vary greatly among different species.

The more individuals there are of a species, the greater the chance that single individuals can survive under harsher conditions. If the number of individuals drops, adaptability first stagnates (roughly estimated at under 500 animals) and then inbreeding begins (roughly from under 50 animals) [Source 4]. In zoo-based species conservation, this is precisely where the problem lies, as small breeding populations require intensive genetic management, and zoos often neither possess sufficient capacity nor can they replace habitat conservation.

At the highest, most complex level is the diversity of ecosystems. Spanning the globe, they are interconnected: from tropical coral reefs, seagrass meadows, and the deep-sea floor, to rivers, forests, and meadows, all the way to ice deserts and the polar tundra. Even on the underside of sea ice, algae and plankton form the basis for a productive, nutrient-rich ecosystem. Ecosystems fix energy in biomass, store carbon, provide oxygen and food, regulate biogeochemical cycles, and can protect coastlines from erosion. These benefits are referred to as ecosystem services and are in most cases far more valuable than any single resource whose extraction would destabilise the ecosystem.

The foundation of a functioning ecosystem is the animal and plant species, microorganisms, and fungi that inhabit it. Within this framework, there are so-called "keystone species" that significantly shape and influence their environment, such as reef-building corals. In environmental conservation, "flagship species" are frequently used – high-profile species whose conservation is promoted to serve as an umbrella for their co-inhabitants in the ecosystem. Species conservation, however, goes far beyond protecting friendly dolphins or cute wildcats; other vital species also thrive under their protective umbrella.

A major challenge in biodiversity conservation is the creeping process through which extinction occurs. First, a once-abundant population of the Earth or the oceans becomes a depleted, rare species. There are only a few rhinos left in Africa's savannas – would their extinction be so catastrophic? From the perspective of a few years, perhaps not. From the perspective of several generations, during which their once-vast numbers were decimated, it is highly so. Our softened perception of change is called the "shifting baseline" syndrome. If we do not actively keep these changes in mind, they fade into oblivion in the course of daily life [Source 5].

The Ocean Ecosystem

The oceans cover 70% of the Earth's surface and contain 93% of the world's water [Source 4]. From the polar caps to the equator, they are interconnected via a vast conveyor belt of ocean currents. These are driven by thermohaline circulation – the ascent of warm water masses and the descent of cold, denser water masses, creating a resulting draft. Everything in the sea is interconnected [Source 6].

The ocean can be broadly categorised into different depth zones and latitudinal gradients. Due to their lifestyle, marine organisms can be distinguished into bottom-dwelling "benthic" species and "pelagic" species that live swimming in the water column.

The nutritional foundation for life in the sea is formed by cyanobacteria and single-celled algae, such as diatoms, which perform photosynthesis in the open ocean and are referred to as phytoplankton. They provide energy for the next level in the food web, the zooplankton. This includes smaller crustaceans such as copepods or krill, but also the larvae of fish, worms, and molluscs. Plankton, like sharks, whales, and most fish, belongs to pelagic life. Almost all marine animals are part of the zooplankton at some point in their life cycle – meaning its role cannot be underestimated. It forms the nutritional basis for almost all larger marine life – from smaller fish to baleen whales and large predators such as sharks or killer whales [Source 7].

Where the continents rise from the waves, shelf seas border our coastlines. These submarine continental shelves extend to a depth of about two hundred metres before sloping steeply into the depths. At the foot of the continental slopes, at depths from 2,000 metres, the deep sea begins. While the "shallow" shelf seas still receive sufficient light for the growth of algae, seagrass, and corals, all life in the deep sea depends on the input of nutrients from above – marine snow. If nutrients are lacking at the surface, for instance due to overfishing or a depleted plankton bloom, life in the deep sea dies as well. This dependency is known as benthic-pelagic coupling and is a factor that is rarely integrated into fisheries management [Source 8].