Ecological Role of Submarine Canyons and Need for Canyon Conservation: A Review

Ulla Fernandez-Arcaya,Pere Puig,Lenaick Menot,Miles Macmillan-Lawler,Jacobo Martín,Ashley A Rowden,Peter Harris,A Louise Allcock,Veerle A I Huvenne,Eva Ramirez-Llodra,Jaime S Davies,Inge M J Van Den Beld,Kerry Howell,Florence Sanchez,Martha Nizinski,Jacopo Aguzzi,Awantha Dissanayake

doi:10.3389/fmars.2017.00005

Abstract

Submarine canyons are major geomorphic features of continental margins around the world. Several recent multidisciplinary projects focused on the study of canyons have considerably increased our understanding of their ecological role, the goods and services they provide to human populations, and the impacts that human activities have on their overall ecological condition. Pressures from human activities include fishing, dumping of land-based mine tailings, and oil and gas extraction. Moreover, hydrodynamic processes of canyons enhance the down-canyon transport of litter. The effects of climate change may modify the intensity of currents. This potential hydrographic change is predicted to impact the structure and functioning of canyon communities as well as affect nutrient supply to the deep-ocean ecosystem. This review not only identifies the ecological status of canyons, and current and future issues for canyon conservation, but also highlights the need for a better understanding of anthropogenic impacts on canyon ecosystems and proposes other research required to inform management measures to protect canyon ecosystems.

Highlights

As resources on land are increasingly depleted, humanity is turning to the oceans, as never before, for new sources of food and materials (Ramirez-Llodra et al, 2011)
As a result of prospective surveys, we know that submarine canyons are major geomorphic features of continental margins, with more than 9000 large canyons covering 11.2% of continental slopes globally (Harris et al, 2014), with an estimated accumulated axis length of over 25,000 km (Huang et al, 2014)
The aims of this review are to: (1) highlight current scientific knowledge concerning canyon ecosystems; (2) describe our current understanding of the role played by canyons in providing ecosystem goods and services; (3) identify the impacts to which canyons are increasingly being subjected; (4) review current frameworks and strategies for protecting canyons, and assess the extent of current canyon conservation worldwide; before (5) identifying directions for future canyon research, with a focus on the conservation needs of canyons

Summary

Introduction

As resources on land are increasingly depleted, humanity is turning to the oceans, as never before, for new sources of food and materials (Ramirez-Llodra et al, 2011). Canyons are characterized by steep and complex topography (Shepard and Dill, 1966; Lastras et al, 2007; Harris and Whiteway, 2011) that influences current patterns (Shepard et al, 1979; Xu, 2011) and provides a heterogeneous set of habitats, from rocky walls and outcrops to soft sediment (De Leo et al, 2014) These geomorphologic features act as preferential particle-transport routes from the productive coastal zone down continental slopes to the more stable deep seafloor (Allen and Durrieu de Madron, 2009; Puig et al, 2014)

Objectives

Findings

Conclusion