Global status, impacts, and management of rocky temperate mesophotic ecosystems

Abstract

The ecology and function of rocky temperate mesophotic ecosystems (TMEs) remain poorly understood globally despite their widespread distribution. They typically occur at 20–150 m (the limit of photosynthesis), and on rocky substratum they support rich benthic communities and mobile fauna. We determined the distribution of rocky TMEs, their conservation status, and their most characteristic biological groups. Rocky TMEs were dominated by algae, turf‐invertebrate matrices (<50 m only), sponges, bryozoans, and cnidarians. The community composition of TMEs differed significantly from shallow (0–15 m) subtidal reefs. Data were geographically biased and variable, available only from the North and South Atlantic, Mediterranean, and Temperate Australasia. Degree of protection of rocky TMEs varied considerably across the world. The biggest threats to rocky TMEs were identified changes in temperature, sedimentation rates, nutrient concentrations, and certain fishing types. We propose a conservation framework to inform future rocky TME management and conservation, highlighting the need to recognize the importance of these biologically diverse and functionally important ecosystems.

Assessment of macroalgae coverage in a scarcely studied deep rocky reef in the tropical eastern Mexican Pacific

“…These factors vary as a function of depth. In most sublittoral ecosystems, it is a common phenomenon that determines the structure of the assemblages (Garrabou et al 2002, Bell et al 2022), e.g. water movement is significantly less in deep water, up to 25-30 m, than in shallow water.…”

“…the geomorphological characteristics of the site determine the influence of the water movement among microenvironments. Similarly, biotic interactions significantly influence the abundance and distribution of organisms in the deep environment (Bell et al 2022, Canessa et al 2022, such as competition for space. An important structuring mechanism in rocky reef communities in which organisms with different types of nutrition limit their growth rates.…”

“…Light incidence, substrate inclination (Antoniadou & Chintiroglou 2005), and sedimentation (Balata et al 2005) are higher on horizontal surfaces than vertical ones, favoring an increase in photosynthetic organisms such as those that form algal turfs. Such factors could play a significant role in the structure of assemblages at Sacramento, as demonstrated in rocky (Bell et al 2022) and biogenic reefs (Ballesteros 2006).…”

“…Rocky reefs have been studied around the world with diverse aims (Airoldi & Cinelli 1997, Barros et al 2001, Piazzi & Cinelli 2001, Piazzi et al 2002, Balata et al 2006, 2007a,b, Wernberg & Connell 2008, Glasby et al 2017, Cordero-Umaña & Santidrián-Tomillo 2020, Bell et al 2022, Canessa et al 2022, Martinez et al 2022. Reef ecosystems are widely distributed throughout Mexico's temperate and tropical coastal areas.…”

Institute Profile: Victoria University of Wellington's Coastal Ecology Laboratory—A Uniquely Situated Research Facility for Subtidal and Intertidal Biology

“…There are several key areas of research focus for staff at the Coastal Ecology Laboratory. These include a strong focus on climate change research (Micaroni et al 2022; Krieger et al 2023), population and community ecology (Shima and Swearer 2016; Carrington et al 2021; Bell et al 2022), and fisheries/marine protection (Eddy et al 2014; Rogers et al 2018; Durante et al 2022). Although we are situated in the temperate zone, we also have a strong focus on coral reef biology, with most of our academics comparing temperate and tropical ecosystem trends in community ecology, eco‐physiology, climate change impacts, and fisheries.…”