Life on Earth is old. Fossil records indicate that the first simple organisms emerged about 3.8 billion years ago, and it took another 1.8 billion years for multicelled organisms to evolve. Life is also extremely diverse. Best estimates put the current number of multicelled species on Earth at about 10 million — probably the greatest number of species that has ever inhabited our planet at a given time.
Extinction is not a new phenomenon; experts estimate that over the Earth’s history, natural causes ranging from competition between species to natural disasters have led to the extinction of about 10 species per year. However, Earth’s biodiversity is now being lost at an unprecedented rate as over 7 billion humans struggle to survive and thrive.
With human-generated pressures from habitat loss, targeted extraction and the impacts of invasive species, best estimates put the current extinction rate between 10 and 100 times higher. Clearly that’s bad news for the extinguished species and the environment they collectively hold together in a complex web of life. It’s also bad for us.
In order to raise awareness about the benefits of nature and the threats that drive extinctions, the United Nations has proclaimed May 22 as the annual International Day for Biological Diversity. This year’s theme is marine biodiversity.
Marine species play innumerable roles that underpin our welfare. Some of these are obvious, but others less so. Following is a selection of just a few marine species and the roles they play in our lives.
1. Tuna: These streamlined, lightning-fast swimmers not only underpin the food and livelihood security of millions of people — they also act as top ocean predators that keep species populations in check to ensure a healthy balance between different levels in the food web. Drastic tuna population declines would likely have negative impacts on ocean health.
2. Krill: Practically at the opposite end of the size spectrum from tuna, which can attain gigantic proportions, billions of tiny krill — small oceanic shrimp-like creatures — serve as the foundation of food chains, especially in the southern oceans.
3. Mangroves: Forming stately forests that cover hundreds of unbroken miles of coastline in some areas, mangroves provide coastal societies with protection from extreme weather events and serve as nursery areas for many species, including fish that are important for both local food security and national revenues.
4. Diatoms: These single-celled, glass covered, free-floating (planktonic) organisms are the most abundant marine species on Earth and sustain the majority of the ocean’s productivity. Without them serving as vast quantities of food for everything else, there would be few more complex life forms. Additionally, diatoms produce much of the oxygen we need.
5. Sharks: The world’s 350 species of sharks live in diverse habitats across the oceans. As top predators, sharks are best known for their ecological role as regulators of ocean health, but they also underpin the cultural identity of Pacific Islanders, as in Hawaii where sharks were revered as deities.
6. Fungi: These organisms have the special ability to help recovery of marine areas affected by contamination. Mycoremediation, a special form of bioremediation, is the process of using fungi to break down and render harmless noxious chemicals, such as petroleum and pesticides, which have accumulated in the environment.
7. Whales: After centuries of overexploitation for oil, food and other products, these days whales are rarely captured — except on camera. Across the globe, whales are a key attraction in a nature tourism industry valued in the hundreds of millions of dollars. Once whales die, they sink to the bottom, where their slowly decaying bodies can serve as the basis for entire benthic (ocean floor) communities for years.
8. Clams: These bivalves are well-known as delicious ingredients in many dishes, including Spanish paella. Less known is the inspiration they provide for industrial design through biomimicry, the process of designing inventions to meet human needs by applying solutions that other species have evolved to solve environmental challenges. By copying the interlocked surfaces of a clam’s shells bound with a flexible strap, inventors produced a simple, remarkably strong system for joining two rigid surfaces that must withstand huge forces that could break them apart.
9. Tunicates: These generally rubbery animals attach themselves to solid surfaces from which they seine passing food from currents for most of their lives. Unremarkable in appearance, tunicates produce some of the most promising potent compounds to fight cancers, including skin melanoma.
The species that are the most important for people varies with location, income group, and over time, as species’ roles change as natural and social environments evolve. In addition, only just over a million of the planet’s species have been formally catalogued — so who knows what benefits the species we haven’t yet documented may hold?
One thing is for sure: Human actions are eroding our natural capital at a rate that far outpaces nature’s ability to generate new species through evolution. As such, we weaken the web of life that sustains us — and we fail in our role as the only species with the consciousness to be aware of our potential as either nature steward or nature robber.
Fortunately, many solutions do exist to allow societies to meet their needs without doing so at the cost of other species — and more solutions are fast developing. Limiting environmental degradation requires moving beyond protecting a few special areas and particular species, although this is a critical first step. CI’s mission is to mainstream these solutions — which primarily involve a focus on economics and governance in addition to biological expertise — so that we can become the responsible stewards we have the potential to be.
Protecting nature is not just good for the species noted above; in fact, this enlightened self-interest will allow both people and nature to win. A blue whale may not be able to thank you, but your grandkids surely will.
Scott Henderson is the regional director of CI’s Eastern Tropical Pacific Seascape program.
Cover image: Eastern Pacific yellowfin tuna. (Brian Skerry)