Loss of Deep-sea Species Could Lead to Collapse
Scientists have demonstrated that deep-sea ecosystem functioning is closely dependent upon the number of species inhabiting the ocean floor. Danovaro “This shows that we need to preserve biodiversity, and especially deep-sea biodiversity, because otherwise the negative consequences could be unprecedented. We must care about species that are far from us and [essentially] invisible.”
Recent investigations on land have suggested that biodiversity loss might impair the functioning and sustainability of ecosystems. The consequences of biodiversity loss on the ocean floor were completely unknown, despite the fact that the deep sea covers 65% of the Earth and is “by far the most important ecosystem for the cycling of carbon, nitrogen, and phosphorus of the biosphere.” The deep sea also supports the largest ‘biomass’ of living things, including a large proportion of undiscovered species.
Nematodes
In this study, Danovaro’s team examined the biodiversity of nematode worms and several independent indicators of ecosystem functioning and efficiency at 116 deep-sea sites. Nematodes are the most abundant animals on earth and account for more than 90% of all life at the bottom of the sea. Nematode diversity is a good proxy for the diversity of other deep-sea species.
They found that sites with a higher diversity of nematodes support exponentially higher rates of ecosystem processes and more efficiency.
Efficiency reflects the ability of an ecosystem to exploit the available energy in the form of food sources. Our results show that a higher biodiversity enhances the ability of deep-sea ecosystems to perform the key biological and biogeochemical processes that are crucial for their sustainable functioning.
The sharp increase in ecosystem functioning as species numbers are higher suggests that individual species in the deep sea make way for more species.
Deep-sea ecosystems provide goods (including biomass, bioactive molecules, food, oil, gas, and minerals) and services (climate regulation, nutrient regeneration) and supply to the upper ocean and humans. For their profound involvement in global biogeochemical and ecological processes, they are essential for the sustainable functioning of our biosphere and for human wellbeing. The results suggest that the conservation of deep-sea biodiversity can be crucial for the sustainability of the functions of the largest ecosystem on the planet.
Roberto Danovaro (Italy) and others
Adapted from: Cell Press
December 29, 2007