The distribution of benthic biomass in hadal trenches : a modelling approach to investigate the effect of vertical and lateral organic matter transport to the seafloor
Ichino, Matteo C.
Clark, Malcolm R.
Drazen, Jeffrey C.
Jones, Daniel O. B.
Martin, Adrian P.
Rowden, Ashley A.
Shank, Timothy M.
Yancey, Paul H.
Ruhl, Henry A.
MetadataShow full item record
KeywordHadal ecology; Sediment; Gravitational transport; Topography; Benthic biomass; Kermadec Trench
Most of our knowledge about deep-sea habitats is limited to bathyal (200–3000 m) and abyssal depths (3000–6000 m), while relatively little is known about the hadal zone (6000–11,000 m). The basic paradigm for the distribution of deep seafloor biomass suggests that the reduction in biomass and average body size of benthic animals along depth gradients is mainly related to surface productivity and remineralisation of sinking particulate organic carbon with depth. However, there is evidence that this pattern is somewhat reversed in hadal trenches by the funnelling of organic sediments, which would result in increased food availability along the axis of the trenches and towards their deeper regions. Therefore, despite the extreme hydrostatic pressure and remoteness from the pelagic food supply, it is hypothesized that biomass can increase with depth in hadal trenches. We developed a numerical model of gravitational lateral sediment transport along the seafloor as a function of slope, using the Kermadec Trench, near New Zealand, as a test environment. We propose that local topography (at a scale of tens of kilometres) and trench shape can be used to provide useful estimates of local accumulation of food and, therefore, patterns of benthic biomass. Orientation and steepness of local slopes are the drivers of organic sediment accumulation in the model, which result in higher biomass along the axis of the trench, especially in the deepest spots, and lower biomass on the slopes, from which most sediment is removed. The model outputs for the Kermadec Trench are in agreement with observations suggesting the occurrence of a funnelling effect and substantial spatial variability in biomass inside a trench. Further trench surveys will be needed to determine the degree to which seafloor currents are important compared with the gravity-driven transport modelled here. These outputs can also benefit future hadal investigations by highlighting areas of potential biological interest, on which to focus sampling effort. Comprehensive exploration of hadal trenches will, in turn, provide datasets for improving the model parameters and increasing predictive power.
© The Author(s), 2015. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Deep Sea Research Part I: Oceanographic Research Papers 100 (2015): 21-33, doi:10.1016/j.dsr.2015.01.010.
Suggested CitationDeep Sea Research Part I: Oceanographic Research Papers 100 (2015): 21-33
The following license files are associated with this item:
Showing items related by title, author, creator and subject.
Benthic foraminifera living in Gulf of Mexico bathyal and abyssal sediments : community analysis and comparison to metazoan meiofaunal biomass and density Bernhard, Joan M.; Sen Gupta, Barun K.; Baguley, Jeffrey G. (2005-12-07)Benthic foraminiferal biomass, density, and species composition were determined at ten sites in the Gulf of Mexico. During June 2001 and June 2002, sediment samples were collected with a GoMex boxcorer. A 7.5-cm diameter ...
Report on Sediment Transport Events on Shelf and Slope (STRESS) field season 1 : Winter 1988-1989 Benthic Acoustic Stress Sensor (BASS) Montgomery, Ellyn T.; Dunn, Christopher V. R.; Williams, Albert J. (Woods Hole Oceanographic Institution, 1989-12)Data on the effects of winter conditions on the transport of sediment on the continental shelf off Northern California were collected during the flrst year of the Sediment TRansport Events on Shelf and Slope (STRESS) ...
Contribution of ocean, fossil fuel, land biosphere, and biomass burning carbon fluxes to seasonal and interannual variability in atmospheric CO2 Nevison, Cynthia D.; Mahowald, Natalie M.; Doney, Scott C.; Lima, Ivan D.; van der Werf, Guido R.; Randerson, James T.; Baker, David F.; Kasibhatla, Prasad S.; McKinley, Galen A. (American Geophysical Union, 2008-02-12)Seasonal and interannual variability in atmospheric carbon dioxide (CO2) concentrations was simulated using fluxes from fossil fuel, ocean and terrestrial biogeochemical models, and a tracer transport model with time-varying ...