20150916 - marine life

Loss of Marine Biodiversity

Life in the ocean, where evolution began, comprises more major taxonomic groups (phyla), which represent separate evolutionary paths, than does life on land. Of the approximately 55 phyla, approximately 80% include species that are marine while about 50% include species found on land. It is therefore certain that in the ocean there are more species that are very different from each other, although it is not yet known which realm has the most species.

The Problem

• Because so much of the ocean is only accessible with expensive technology and/or remote instrumentation, uncovering the extent of marine biodiversity has been and continues to be a slow and difficult undertaking. Much of ocean life remains a mystery and there are an unknown number of species yet to be discovered. Consequently, scientific estimates of the number of species in the ocean vary greatly, ranging from many thousands to several tens of millions.
• It is also difficult -- and in many cases impossible -- to determine the status of most species in the ocean. So little is known of many species' distribution or range that it cannot be determined whether they are plentiful or naturally rare or whether populations are stable or changing, and if they are threatened or endangered. Marine species that are relatively easily monitored are those restricted to near-shore habitats, especially if they are sedentary or attached (e.g. seagrasses and corals) and those that spend time at the sea surface or on land (e.g. marine mammals and seabirds).

 http://www.seaweb.org/resources/briefings/marinebio.php
 http://www.slideshare.net/rdn100/marine-biodiversity-presentation