Positive species interactions strengthen in a high-CO2 ocean ...

• Main Authors: Ferreira, Camilo, Connell, Sean, Goldenberg, Silvan, Nagelkerken, Ivan
• Format: Dataset
• Language: English
• Published: Dryad 2021
• Subjects: FOS Biological sciences; Species interactions; bottom-up processes; top-down processes; prey; farming; Parma; Ocean acidification
• Online Access: https://dx.doi.org/10.5061/dryad.vdncjsxtk; https://datadryad.org/stash/dataset/doi:10.5061/dryad.vdncjsxtk

Negative interactions among species are a major force shaping natural communities and are predicted to strengthen as climate change intensifies. Similarly, positive interactions are anticipated to intensify, and could buffer the consequences of climate-driven disturbances. We used in situ experiments at volcanic CO2 vents within a temperate rocky reef to show that ocean acidification can drive community reorganization through indirect and direct positive pathways. A keystone species, the algal-farming damselfish Parma alboscapularis, enhanced primary productivity through its weeding of algae whose productivity was also boosted by elevated CO2. The accelerated primary productivity translated into increased densities of primary consumers (herbivorous invertebrates), which indirectly supported increased secondary consumers densities (predatory fish) (i.e. strengthening of bottom-up fuelling). However, this keystone species also reduced predatory fish densities through behavioural interference, releasing ... : Primary productivity We used 36 plots (18 at vents and 18 at controls) distributed at the same depth range (6–8 m depth) to test farming and CO2 enrichment effects on algal production (calculated as mg of O2 produced per algal biomass, O2 mg.g-1). Eighteen of the 36 plots (9 at vents, 9 at controls) were covered by a cage to exclude feeding and farming by the keystone species, whilst 18 (9 at vents, 9 at controls) were open plots in which the keystone species was allowed to feed and weed. Individual cages and open plots each covered a substratum area of 225 cm2. The exclusion cages were constructed from reinforced construction metal grid and were covered by wire mesh (12 × 12 mm mesh size), with a dimension of 15 × 15 × 15 cm. The mesh size did not prevent the movement of prey and predators in and out of the experimental plot. All cages and plots were placed in the centre of the farms and fixed to the substratum with 2-mm heavy-duty multi-filament rope. The cages were scrubbed every 12 days. Turf algal ...