Transport and transformation of dissolved and particulate materials on continental margins influenced by major rivers: benthic boundary layer and seabed processes

Abstract

Within the benthic boundary layer (BBL) and seabed of river-dominated ocean margins (RiOMars), the timing, kinetics and extent of important biogeochemical processes are greatly influenced by large riverine inputs of dissolved and particulate terrestrial materials. An examination of our current state of knowledge reveals that the rates of primary productivity, sediment deposition, remineralization and burial in these margins are among the highest of all marine systems. Transport and transformation processes within the benthic region of these RiOMar areas are highly variable (temporally and spatially). As a result, measurement and modeling of these processes are very challenging. A more quantitative understanding of these systems will require coordinated interdisciplinary studies that: (a) better define the quantity and composition of riverine inputs; (b) greatly improve our current knowledge of transport and transformation within the BBL of these systems; (c) focus on the sequential timing of physical forcings (riverine discharge, high energy events); (d) develop new nonclassical diagenetic models; (e) further characterize and delineate differences between sub-environments within a RiOMar and between RiOMar “types”; and, (f) provide a better mechanistic understanding of what controls the net retention of terrestrial materials (diagenetic transformation vs. burial) within RiOMar systems.