Water and Biodiversity

Water covers 71% of the Earth’s surface. 96.5% of Earth’s water is found in oceans, 1.7% in groundwater, 1.7% in glaciers and ice caps, and 0.001% in vapor and clouds. Only 2.5% of that water is freshwater, with most of that found in ice and groundwater.

Water is essential for all life on Earth. From the smallest microbe to the largest known life form on Earth – the Blue Whale – life cannot exist without water.

Today is the International Day for Biological Diversity, and the theme is Water and Biodiversity. This theme was chosen to coincide with the International Year of Water Cooperation (2013, as designated by the United Nations), which was specifically celebrated on March 22 as World Water Day. The objective of World Water Day and the International Year of Water Cooperation is to raise awareness about challenges facing water management and ties to sustainable development while also exploring ways to cooperate to ensure that everyone has access to the clean water needed to survive.

The International Day for Biological Diversity was established in 1993 by the United Nations “to increase awareness and understanding about biodiversity issues.” It occurs every year on May 22 and is organized by the Convention on Biological Diversity.

While all life depends on water, aquatic species live in water for most or all of their lives. The diversity of aquatic animals and plants is staggering, and the adaptations developed to support this wet lifestyle are numerous. For instance, some breathe by absorbing oxygen in the water through their skin or using gills. Others breathe air, but are specially adapted to hold their breath for extended periods of time. For instance, the sperm whale, one of the deepest-diving mammals, can remain submerged for 90 minutes!

Sperm Whale. Compléments de Buffon. T. 1 (1838).

To celebrate the International Day for Biological Diversity and the International Year of Water Cooperation, we’ve created a collection of aquatic species illustrations from BHL. We hope you take some time to enjoy the images but also consider what you can do to support water security. Not convinced it’s an issue? Take a look at the implications of water insecurity from the Convention on Biological Diversity.