Marine biodiversity is the variability of life in marine ecosystems. Marine ecosystems include oceans, salt marshes, estuaries, lagoons, coral reefs, shores, and some of the tropical ecosystems (like mangrove forests). They are part of a larger, world ecosystem, and are characterized by having a much greater salinity level than freshwaters.
Even though marine ecosystems are teeming with life, the species diversity is much lower than that of other ecosystems. Only about 230,000 species have been identified, and that number includes both plants and animals.
Much of marine biodiversity resides in ecosystems based around coral reefs and/or areas of underwater tectonic activity. They hold over a quarter of the world’s marine species. One third of the coral species are currently threatened with extinction. This is a rise over the last decade from less than two percent. Unfortunately, coral reefs all over are dying due to many forms of damage, all originating from one source: human beings. Snorkeling, commercial fishing and overfishing, fuel leaks from both commercial and recreational boats all contribute to the damage or outright destruction of both the coral reefs and marine biodiversity in general. Climate change can also affect coral reefs, the rising temperatures making them reject the algal growths that help the process of photosynthesis. 1998, one of the warmest years, saw mass die-offs of coral reefs all over the world.
Given that life originated in the sea, it is not surprising that there are fourteen endemic animal phyla in the sea, as opposed to the one phylum endemic to land. The situation is much different for plants, however. Almost all algae type plants can appear in both marine and freshwater, with the higher classes of plants only growing on land. The diversity of life-history strategies in marine organisms has proven to be remarkable to the point where scientists are expecting that the total of genetic resources and physiological marine biodiversity will be much greater than that of land organisms.
Without marine biodiversity, humankind would suffer greatly since marine organisms are crucial to almost all biogeochemical processes of the biosphere. They also help provide a variety of products and services essential to mans survival and well-being. Without marine biodiversity the production of food, ingredients for biotechnology and pharmaceuticals, and even the composition of some parts of land would be either severely diminished or depleted altogether.
For all the above reasons, as well as for the fascination and great beauty it provides, marine biodiversity is one of our greatest treasures and must be protected and shepherded accordingly.