Location and associated carbon storage of erosional escarpments of seagrass Posidonia mats

Authors

Oscar Serrano, Edith Cowan UniversityFollow
Paul Lavery, Edith Cowan UniversityFollow
Lourdes Lopez-Merino
Enric Ballesteros
Miguel A. Mateo, Edith Cowan UniversityFollow

Document Type

Journal Article

Publisher

Frontiers

School

School of Science / Centre for Marine Ecosystems Research

RAS ID

22429

Funders

ECU Faculty Research Grant Scheme

ECU Early Career Research Grant Scheme

CSIRO Flagship Marine and Coastal Carbon Biogeochemical Cluster (Coastal Carbon Cluster)

Project SUMILEN (CTM2013-47728-R, Spanish Ministry of Economy and Competitiveness)

The Leverhulme Trust toward an Early Career Fellowship (ECF-2013-530)

Comments

Serrano, O., Lavery, P. S., López-Merino, L., Ballesteros, E., & Mateo, M. A. (2016). Location and associated carbon storage of erosional escarpments of seagrass Posidonia mats. Frontiers in Marine Science, 3, 42.

https://doi.org/10.3389/fmars.2016.00042

Abstract

Seagrasses of the genus Posidonia can form an irregular seascape due to erosional processes exposing thick walls of organic matter-rich soils. However, little is known about the location and characteristics of these particular formations. Here we provide comprehensive estimates of organic carbon (C_org) storage in Posidonia oceanica and Posidonia australis meadows, while providing insight into their location and mechanisms of formation, and highlighting future research directions. Erosional reef escarpments are restricted to shallow highly productive P. oceanica meadows from the Mediterranean Sea and P. australis meadows from the Indian Ocean, and sustain the existence of C_org-rich deposits in surrounding meadows. The thickness of the mat escarpments can reach up to 3 m and their length can vary from few to hundreds of meters. Mechanisms of formation appear to differ among sites, from naturally-induced escarpments by wave action and/or tidal flow to human-induced escarpments by dredging activities. The inter-twined remains of seagrass shoots within the sediment matrix consolidate the sandy substrate and hold the exposed Posidonia mat escarpments together, maintaining a semi-rigid structure. This phenomenon is unusual but of exceptional importance in marine biogeochemical cycles, revealing the largest C_org sinks among seagrasses worldwide (ranging from 15 to 176 kg C_org m⁻² in 2 m-thick mats accumulated at 2–249 g C_org m⁻² yr⁻¹ over 300–3000 yr).

DOI

10.3389/fmars.2016.00042

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