Mid ocean ridge plus#
Mid ocean ridge series#

However despite their ubiquity, locally high biomass and productivity, vent fields are small and sparsely distributed so can only make a minor contribution to mid-ocean biological productivity. Abundant chemosynthetically-supported life is found around hydrothermal vents that occur along ridge axes. Whilst the geological function of the mid-ocean ridge system is well known, its biological significance remains uncertain. This forms part of the global mid-ocean ridge system occupying 33% of the total ocean floor that plays a major role in plate tectonics as the site of formation of new earth's crust. By the 1950s sonar surveys had revealed the structure of the MAR with a tectonically active central rift valley bounded by elevated flanks on either side, sloping down to the abyssal plains. The Mid-Atlantic Ridge (MAR) was described a century ago as the most striking feature of the Atlantic Ocean dividing the ocean into eastern and western deep basins.

Mid ocean ridge plus#

We propose that globally sea floor elevation has no effect on deep sea biomass pelagic plus benthic biomass is constant within a given surface productivity regime. There is no enhancement of biological productivity over the MAR oceanic bathypelagic species are replaced by benthic fauna otherwise unable to survive in the mid ocean. This is approximately equal to 167 kt C of estimated pelagic biomass displaced by the volume of the MAR. A hypothetical flat plain at 3500 m depth in place of the MAR would contain 85.6 kt C, implying an increase of 173.3 kt C attributable to the presence of the Ridge. Biomasses of benthic macrofauna and megafauna were similar to global averages at the same depths totalling an estimated 258.9 kt C over the entire lower bathyal north MAR. Primary production and export flux over the MAR were not enhanced compared with a nearby reference station over the Porcupine Abyssal Plain. The MAR fauna comprises mainly species known from continental margins with no evidence of greater biodiversity.

Mid ocean ridge series#

The MAR, 3,704,404 km 2 in area, accounts for 44.7% lower bathyal habitat (800вЂ“3500 m depth) in the North Atlantic and is dominated by fine soft sediment substrate (95% of area) on a series of flat terraces with intervening slopes either side of the ridge axis contributing to habitat heterogeneity. Satellite remote sensing provided information on flow patterns, thermal fronts, and primary production, while sediment traps measured export flux during 2007вЂ“2010. We investigated the origin of this apparent biological enhancement over a segment of the North Mid-Atlantic Ridge (MAR) using sonar, corers, trawls, traps, and a remotely operated vehicle to survey habitat, biomass, and biodiversity.

In contrast to generally sparse biological communities in open-ocean settings, seamounts and ridges are perceived as areas of elevated productivity and biodiversity capable of supporting commercial fisheries.