Difference between revisions of "The Ocean as a natural heritage"
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Latest revision as of 12:11, 8 August 2019
The Tree of Life
THE ORIGIN OF LIFE
Microbial life originated in the ocean an estimated 3.6 billion years ago, and eukaryotic life some 2.1 to 3.0 billion years ago. A wide diversity of multicellular life appeared some 1.26-0.95 billion years ago. Land became colonized by green plants 0.60 billion years ago and man has joined life on earth a mere 200,000 years ago. The long evolution on Planet Ocean has generated a wealth of biodiversity at the gene, species and ecosystem level. Some aspects have received a disproportionate level of attention with concentration on a top down approach where organisms close to man such as whales, fish and shellfish have been prioritized. In contrast others have been neglected, such as the microbes and viruses. Genomics helps with this.
GENOMICS AND THE TREE OF LIFE
A total of 212,000 species have been identified in the ocean , but the tally on species diversity is expected to reach millions, possibly even more than on land. However, we know very little about most species identified, let alone those yet to be discovered. Building the ultimate Tree of Life is a huge challenge, and several conditions have to be met.
LOSS OF BIODIVERSITY
Why do we prepare seemingly endless lists of species of marine organisms? It is foremost an attempt to understand the functioning of the biosphere and hence to help manage the services and goods delivered. Organisms occupy habitats and form an integral part of ecosystems, whose function and dynamics are determined by the variety, abundance and activities of these organisms. The diversity shift is monitored through taxonomic experts and compiled in a global database Census of Marine Life – CoML. There is growing evidence for the loss of population diversity, where smaller or more delicate (e.g., deep-sea and polar) populations are the first victims 
MICROORGANISMS AND THE GLOBAL BIOLOGICAL PUMP
Genomics has already provided a breakthrough in assessing the diversity, importance and functioning of the smallest creatures in the ocean—the picoplankton, creatures of less than 2 μm. This thriving community is ecologically overwhelming with an estimated contribution to primary productivity of on average 50% to 90% ; it essentially drives biogeochemical processes. The ocean stores huge amounts of carbon in living creatures and dead organic matter. This process is intimately linked to the cycling of oxygen and the life cycle of living organisms. They shuttle carbon, oxygen and nitrogen between the ocean surface, the abyss and again to the surface. Microorganisms, such as the picoplankton play a crucial role in this system through CO2 sequestration, control of the ocean’s acidity, productivity and dynamics. Rapid changes in global climate tend to modify or even offset this balance. The slow down of global ocean currents (the so called conveyer belt) through changes in atmospheric heat distribution, will affect the biochemical and physiological capacities of marine organisms. Such changes can be monitored through metagenomic approaches. The biological pump described above is of crucial importance for life on earth. Continuous monitoring needs to be provided through permanent off-shore stations with remote sensing to evaluate marine biomass production at all levels and then combined with confirmatory experiments at the laboratory and field scale.
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