Impacts on the Deep-Sea Ecosystem by a Severe Coastal Storm

Abstract

Major coastal storms, associated with strong winds, high waves and intensified currents, and occasionally with heavy rains and flash floods, are mostly known because of the serious damage they can cause along the shoreline and the threats they pose to navigation. However, there is a profound lack of knowledge on the deep-sea impacts of severe coastal storms. Concurrent measurements of key parameters along the coast and in the deep-sea are extremely rare. Here we present a unique data set showing how one of the most extreme coastal storms of the last decades lashing the Western Mediterranean Sea rapidly impacted the deep-sea ecosystem. The storm peaked the 26th of December 2008 leading to the remobilization of a shallow-water reservoir of marine organic carbon associated with fine particles and resulting in its redistribution across the deep basin. The storm also initiated the movement of large amounts of coarse shelf sediment, which abraded and buried benthic communities. Our findings demonstrate, first, that severe coastal storms are highly efficient in transporting organic carbon from shallow water to deep water, thus contributing to its sequestration and, second, that natural, intermittent atmospheric drivers sensitive to global climate change have the potential to tremendously impact the largest and least known ecosystem on Earth, the deep-sea ecosystem.

A new approach for assessing cold-water coral growthin situusing fluorescent calcein staining

“…Interestingly, compared with the experiments of Orejas et al (2008Orejas et al ( , 2011, the mean in situ polyp growth rate in our study is still lower than in aquaria, which suggests that CWC corals are limited in food supply (qualitatively or quantitatively) in the Lacaze-Duthiers canyon. However they should benefit from falling organic matter during winter cascading events or severe coastal storms (Heussner et al 2006;Sanchez-Vidal et al 2012). Temperature drop and increase in current velocity are additional stress factors associated with dense shelf water cascading that might affect CWC coral growth (Company et al 2008).…”

First records, rediscovery and compilation of deep-sea echinoderms in the middle and lower continental slope of the Mediterranean Sea

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Biogeochemical characterization of the riverine particulate organic matter transferred to the NW Mediterranean Sea

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