Central Waters
The realm of the Central Waters, the wide expanses of open ocean that cover the marjority of our planet, encompasses the Light and Dark zones.
Light Zone (Drifters and Swimmers)
At least 40% of the world’s primary production occurs in the open ocean and much of this production is consumed by a community dominated by planktonic crustaceans (drifters). These organisms are relatively well studied and generally considered to be cosmopolitan. The focus among the light drifters is on the question of whether this community is consistent globally or merely convergent in a zone that requires highly constrained lifestyles. This question requires a global molecular approach to compare populations in the ocean basins.
In contrast, there is now no question about the basin-wide and even global connections among the large pelagic animals (swimmers) in this zone. Individual recognition, tagging and now real-time tracking of many species leaves no doubt of the scale on which these top predators must be studied. We cannot sum the whale counts in Alaska and Mexico or the tuna counts in Mexico and Japan to get a census – they are the same individuals! New technologies are now making it possible to provide realistic estimates of the global distribution and abundance in this realm, and the animals themselves are identifying the ‘ocean oases’ where they concentrate to feed on smaller species of taking advantage of production hotspots.
Two CoML field projects are designed for this zone:
Marine Zooplankton: CMarZ
A global, taxonomically comprehensive biodiversity assessment of animal plankton, including ~6,800 described species in fifteen phyla, using emerging technologies in DNA analysis.
Top Predators: TOPP
A program using electronic tagging technologies to study migration patterns of large open-ocean animals and the oceanographic factors controlling these patterns.
Dark Zone (Mid-water and Bottom-water)
Extending down more than 4 km into pitch-blackness, the dark zone’s volume exceeds the volume of the 200 m light zone manyfold. Even in the dark most animals must feed ultimately on plants from nearer the surface, which deliver a marine snow into the dark zone. The snow of wastes, carcasses of large animals, and swimmers venturing below their normal light zone feed the animals in the dark beneath. The mass of organisms declines with depth, modified by mid-ocean ridges that affect circulation just as mountains affect weather. At best the technology to explore these dark, deep waters is brand-new, and at worst it is still inadequate. The challenge of exploration includes midwaters with crustaceans, fish and strange floating jellyfish and mollusks, as well as bottom waters with an even broader spectrum of species. The falling snow collects at the bottom, so food is plentiful, and creatures here can rest on the bottom without the strange and specialized floatation and swimming structures required above.
One CoML field project is underway in this zone:
Mid-Ocean Ridges: MAR-ECO
An international exploratory study of the macrofauna of the northern mid-Atlantic Ocean including the processes that control their distribution and community structures in the waters around the Mid-Atlantic Ridge.
