Editorial preface to special issue: Biocalcifier resilience and response during Phanerozoic global climate changes

Through the Phanerozoic, the Earth has experienced several environmental disturbances characterised by varied tempos and modes of ecosystem resilience and response, and organisms that secrete calcium carbonate skeletons (calcifiers) have been especially vulnerable. These events have occasionally reached ecological tipping points, triggering permanent changes in the abundance, biodiversity, ecological range and biomineralization processes of marine calcifiers. Today benthic and planktic marine calcifiers are most impacted by these global perturbations; therefore, it is important to understand how calcifiers responded to global climatic and environmental perturbations in the recent and distant past in order to understand future resilience. This Virtual Special Issue (VSI), entitled Biocalcifier resilience and response during Phanerozoic global climate changes, comprises 17 papers that document the adaptative response of marine calcifiers to global stresses, dealing with examples from the geological record and from modern biota. Papers span from the Permian to the Recent, and consider pelagic organisms, benthic organisms, and integrated studies of pelagic and benthic ecosystems. Some of the main findings are as follows: (1) Planktic communities show a greater ecological resilience than benthic ones; (2) Most perturbations trigger ecological shifts rather than complete biotic turnovers, the exceptions being the end-Permian and Triassic-Jurassic boundary crises which led to ecosystem collapse and extinctions; and (3) Benthic ecosystems often respond through reorganization into new community assemblages. It is important to emphasise that each event represents a unique case study, where different duration and environmental stressors are key factors in determining organismal survival and ecosystem restructuring. The papers presented will be of help in detecting the most vulnerable and/or highly tolerant and resilient taxa in order to quantify the most common responses and adaptive strategies to current climate changes.