Management and Exploitation of Macroalgal Biomass as a Tool for the Recovery of Transitional Water Systems

Adriano Sfriso,Cristina Munari,Alessandro Buosi,Andrea Augusto Sfriso,Michele Mistri

doi:10.3389/fevo.2020.00020

Adriano Sfriso, Cristina Munari + Show 3 more

Open Access

https://doi.org/10.3389/fevo.2020.00020

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Abstract

Aquatic angiosperms favor the development of ecosystems services, the welfare of marine organisms and people. Generally the presence of angiosperms in transitional systems are indicators of good ecosystem status. Presently, these environments are densely populated and often are so highly degraded that angiosperms have almost disappeared, replaced by tionitrophilic macroalgae responsible of anoxic events that deteriorate the environment furtherly. Although this trend is hardly reversible because the anthropogenic impact is increasing and the restoring of damaged environments within a reasonable time is difficult, recent studies have shown that by managing the harvesting of the natural algal species of commercial interest a progressive environmental recovery is achievable. Biomass-harvesting can contribute both to the removal of high amounts of nutrients and the generation of economic revenues for a sustainable, self-financed environmental restoration. In fact, unlike clam-farming which destroys the seabed and re-suspends large amounts of sediments, the proper management of the macroalgal biomass, can favour the nutrient abatement and the recolonization of aquatic angiosperms which help restore the conditions necessary for the conservation of the benthic and fish fauna and birds, and produce valuable economic resources.

Highlights

Primary producers in transitional water systems (TWS) are mainly represented by macrophytes: aquatic angiosperms and macroalgae
A conceptual framework for ecosystem services (ES) classification was established in the studies of the Millennium Ecosystem Assessment and the Economics of Ecosystems and Biodiversity (Arico et al, 2005; Barker et al, 2010) that define four major classes, inclusive of numerous subclasses, based on the kind of service provided by ecosystems for human well-being (Liquete et al, 2013; Hattam et al, 2015; Haines-young and Potschin, 2018), i.e., Regulation services, Habitat services, Provisioning services, and Cultural services
Pialassa della Baiona showed two stations covered with a high macroalgal biomass, but excluding salt marshes and canals only ca. 3 km2 showed a biomass ≥3 kg fw m−2

Summary

Introduction

Primary producers in transitional water systems (TWS) are mainly represented by macrophytes: aquatic angiosperms and macroalgae. The former usually prevail over the others, but that depends on the ecological status of the study area. Aquatic angiosperms reduce sediment resuspension, favor clear waters, contrast sediment erosion, and contribute to permanent CO2 sequestration (Regulation services); provide shelter and nursery areas for benthic and fish fauna and pasture areas for birds (Habitat services); increase recreational activities (Cultural services); and sustain traditional fishing activities (Provisioning services) as a consequence of a general improvement of the environment. In pristine environments the calcareous species trap CO2, whereas in degraded environments other taxa accumulate nutrients (Sfriso and Marcomini, 1994; Sfriso et al, 1994) and contaminants (Maroli et al, 1993) (Habitat services)

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