All raw data files, csv files, and R code to reproduce stats and graphics within manuscript
ABSTRACT Globally, species are migrating in an attempt to track optimal isotherms as global climate change increasingly warms existing habitats. There are orders of magnitude difference in the distances each species can migrate within a given time period. Organisms that are sessile as adults are particularly slow to shift their range since they can only migrate through sexual dispersal. Stony corals are severely threatened by anthropogenic warming, which has resulted in repeated mass bleaching and mortality events in the last decade. Poleward migration of corals is observed but since corals are sessile as adults and with a relatively old age of sexual maturity, they are slow to latitudinally migrate. Another possibility for corals is vertical migration in the water column to deeper, cooler reefs. Herein we describe new observations of the Mediterranean coral Oculina patagonica at far greater depths than previously recorded; a shift from less than 10 meters depth to mesophotic depths (>30 meters). We report this in the context of migration in response to rapidly warming sea surface temperatures on the Israeli Mediterranean coastline. In contrast to the vast latitudinal distance required to track temperature change, this species has migrated deeper where summer temperatures are up to 2°C cooler. When comparing physiology, morphology, trophic position, symbiont type, and photochemistry between deep and shallow conspecifics we found very few depth specific differences. Since shallow colonies of this species typically inhabit low light environments (caves and crevices) and have a facultative relationship with photosymbionts, we suggest that this species was already primed for life in deeper waters and the existing phenotype aided rapid colonization of the new habitats. This observation of coral migration from shallow to deep waters lends support for the ability of other species to follow.
Two R files are provided. "Oculina_Bellworthy_graphs&stats" includes assumption testing and statistical testing of differences between sampling depths. Also here are the construction of graphics and graph panels for figures. "Oculina_Bellworthy_RLC parameters" takes raw relative electron transport data output from the pulse amplitude modulated fluorometer light curves and computes the photosynthestic parameters rETRmax, Ek, alpha, and beta. This file also contains statistical testing and graphics construction for these parameters.
All .csv files are either called for as input data for the code or are output data files from the code. These are raw data files.