Seawater Acidification Affects Beta-Diversity of Benthic Communities at a Shallow Hydrothermal Vent in a Mediterranean Marine Protected Area (Underwater Archaeological Park of Baia, Naples, Italy)

Abstract

One of the most important pieces of climate change evidence is ocean acidification. Acidification effects on marine organisms are widely studied, while very little is known regarding its effects on assemblages’ β-diversity. In this framework, shallow hydrothermal vents within a Marine Protected Area (MPA) represent natural ecosystems acting as laboratory set-ups where the continuous carbon dioxide emissions affect assemblages with consequences that can be reasonably comparable to the effects of global water acidification. The aim of the present study is to test the impact of seawater acidification on the β-diversity of soft-bottom assemblages in a shallow vent field located in the Underwater Archeological Park of Baia MPA (Gulf of Naples, Mediterranean Sea). We investigated macro- and meiofauna communities of the ‘Secca delle fumose’ vent system in sites characterized by sulfurous (G) and carbon dioxide emissions (H) that are compared with control/inactive sites (CN and CS). Statistical analyses were performed on the most represented macrobenthic (Mollusca, Polychaeta, and Crustacea), and meiobenthic (Nematoda) taxa. Results show that the lowest synecological values are detected at H and, to a lesser extent, at G. Multivariate analyses show significant differences between hydrothermal vents (G, H) and control/inactive sites; the highest small-scale heterogeneities (measure of β-diversity) are detected at sites H and G and are mainly affected by pH, TOC (Total Organic Carbon), and cations concentrations. Such findings are probably related to acidification effects, since MPA excludes anthropic impacts. In particular, acidification markedly affects β-diversity and an increase in heterogeneity among sample replicates coupled to a decrease in number of taxa is an indicator of redundancy loss and, thus, of resilience capacity. The survival is assured to either tolerant species or those opportunistic taxa that can find good environmental conditions among gravels of sand.

Chemical characterisation of PM10 from ship emissions: a study on samples from hydrofoil exhaust stacks

“…In the same overcrowded area (Appolloni et al 2018b), two small marine protected areas (Gaiola and Baia) are also present, sensitive to the emissions due to harbours and emissions from ships (Donnarumma et al 2019;Appolloni et al 2020). In addition, the harbours are close to a densely populated urban area (about 1,000,000 inhabitants), which is characterized by the presence of many other pollutant emission sources: vehicular traffic, domestic and commercial combustions and air traffic due to the nearby Capodichino Airport.…”

Submarine Shallow-Water Fluid Emissions and Their Geomicrobiological Imprint: A Global Overview

“…Low structural and functional diversity with high biomass and dominance of a few species was the result of investigating the nematofauna of the same site (Baldrighi et al, 2020). Combining investigations of macro and meiofauna, acidification was found to markedly affect β-diversity in the system (Appolloni et al, 2020). An increase in heterogeneity among sample replicates coupled to a decrease in number of taxa was argued as an indicator of redundancy loss and of resilience capacity.…”

Antarctic Special Protected Area 161 as a Reference to Assess the Effects of Anthropogenic and Natural Impacts on Meiobenthic Assemblages

“…Furthermore, they are more abundant, compared to the macrobenthic taxa, and require only a limited sediment volume to obtain representative samples [6]. Because of their widespread distribution, high turnover rate, life cycles spent entirely in the sediment, high biodiversity, and specific ecological requirements, meiobenthos responds more precociously to several types of environmental changes (e.g., [7][8][9][10][11][12]). Hence, they are considered effective bio-indicators of natural and anthropogenic disturbances (e.g., [13][14][15]).…”