Endangered Species

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

The 2019 IPBES report confirms that of the 8 million plant and animal species worldwide, approximately 1 million species are threatened with extinction [Sources 1-3].

To date, humanity knows too little about biodiversity and the interconnectedness of Earth's ecosystems. Despite this, we continue to relentlessly destroy the habitats of millions of animals and plants. While some of the destruction caused by humans on land is visible to the naked eye (and yet largely remains unaddressed), destruction below sea level is completely lost from view. What we do not see remains hidden, and thus humanity continues to exploit the oceans without mercy.

The critical issue is that while we still fail to comprehend many ecological relationships on land, the marine ecosystem is considerably more complex. Organisms complement one another; even the smallest organism occupies an essential niche and, if lost, could disrupt or even collapse this highly fragile ecosystem.

Biodiversity

Biodiversity, or biological diversity, is structured into three broad levels and is crucial 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 remains under threat.

When hearing the term "biological diversity", most people likely first think of species extinction. This is indeed closely linked, but the concept encompasses more: the diversity of ecosystems, of species, and of their genetic material.

Adaptation to environmental changes and speciation are only possible through the exchange and modification ("mutation") of genetic material. The larger the population of a species, the greater the probability that individual organisms can survive under harsher conditions. If the number of individuals declines, adaptability first stagnates (critically estimated below 500 individuals) and subsequently leads to inbreeding (occurring roughly below 50 individuals) [Source 4]. Notably, this is also the reason why species preservation in zoos is challenging, if not virtually impossible.

At the highest, most complex level is the diversity of ecosystems. Spanning the globe, they are interconnected: from tropical coral reefs, seagrass meadows, and deep-sea floors to rivers, forests, and meadows, all the way to ice deserts and polar tundras. Even on the underside of sea ice, algae and plankton form the basis for a productive, nutrient-rich ecosystem. In their entirety, these ecosystems produce oxygen and energy, prevent soil erosion and degradation, sequester carbon from the atmosphere, and provide food for human consumption. 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 consists of the animal and plant species that inhabit it. Within this framework, there are so-called "keystone species" that fundamentally shape and influence their environment, such as reef-building corals. In conservation, "flagship species" are frequently utilised—charismatic species whose preservation is promoted to serve as surrogates for the protection of other co-occurring species in the ecosystem. Biodiversity conservation, however, extends far beyond protecting appealing dolphins or wildcats; beneath their protective umbrella, other essential species also thrive.

One challenge in biodiversity conservation is the gradual nature of the extinction process. Initially, a populous global or marine community dwindles into a depleted, rare species. Only a few rhinoceroses remain in Africa's savannahs—would their extinction be fatal? From the perspective of a few years, perhaps not. However, from the perspective of several generations, over which their once large numbers were decimated, the loss is profound. Our desensitised perception of change is termed "shifting baseline syndrome". If we do not actively keep these historical changes in mind, they fade from daily consciousness [Source 5].

The Ocean Ecosystem

Oceans cover 70% of the Earth's surface and contain 93% of the world's water [Source 4]. From the polar ice caps to the equator, they are linked 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 continuous physical draw. Everything in the ocean is interconnected [Source 6].

The ocean can be broadly categorised into various depth zones and latitudinal gradients. Marine organisms can be classified based on their lifestyle into bottom-dwelling "benthic" species and "pelagic" species that swim or drift in the water column.

The primary production supporting marine life is generated by cyanobacteria and single-celled algae, such as diatoms, which conduct photosynthesis in the open ocean and are collectively termed phytoplankton. They provide energy for the next trophic level, the zooplankton. This level includes small crustaceans such as copepods or krill, as well as the larvae of fish, worms, and molluscs. Plankton, alongside sharks, whales, and most fish, constitutes pelagic life. Almost all marine organisms are part of the zooplankton at some stage in their life cycle—hence, its ecological significance cannot be overstated. It forms the nutritional basis for almost all larger marine life, from small fish to baleen whales and apex predators such as sharks or killer whales (*Orcinus orca*) [Source 7].

Where landmasses rise from the waves, continental shelves border our coasts. These submerged continental plates extend to a depth of about two hundred metres before sloping steeply into the abyss. At the base of the continental slopes, at depths starting from 2,000 metres, lies the deep sea. While the shallow shelf seas still receive sufficient sunlight to support the growth of algae, seagrass, and corals, all deep-sea life depends on the influx of organic matter from above—often referred to as marine snow. If nutrients are depleted at the surface, for instance due to overfishing or a collapsed plankton bloom, deep-sea life is systematically impacted. This dependency is known as benthic-pelagic coupling, a factor that is rarely integrated into fisheries management [Source 8].