Phytoplankton production drives marine ecosystem trophic-structure and global fisheries yields. Phytoplankton biomass is particularly influential near coral reef islands and atolls that span the oligotrophic tropical oceans. The paradoxical enhancement in phytoplankton near an island-reef ecosystem—Island Mass Effect (IME)—was first documented 60 years ago, yet much remains unknown about the prevalence and drivers of this ecologically important phenomenon. Here we provide the first basin-scale investigation of IME. We show that IME is a near-ubiquitous feature among a majority (91%) of coral reef ecosystems surveyed, creating near-island ‘hotspots' of phytoplankton biomass throughout the upper water column. Variations in IME strength are governed by geomorphic type (atoll vs island), bathymetric slope, reef area and local human impacts (for example, human-derived nutrient input). These ocean oases increase nearshore phytoplankton biomass by up to 86% over oceanic conditions, providing basal energetic resources to higher trophic levels that support subsistence-based human populations.

Growth rate in ectotherms, including most fish, is a function of temperature. For decades, agriculturalists (270+ years) and entomologists (45+ years) have recognized the thermal integral, known as the growing degree-day (GDD,°C·day), to be a reliable predictor of growth and development. Fish and fisheries researchers have yet to widely acknowledge the power of the GDD in explaining growth and development among fishes. We demonstrate that fish length-at-day (LaD), in most cases prior to maturation, is a strong linear function of the GDD metric that can explain >92% of the variation in LaD among 41 data sets representing nine fish species drawn from marine and freshwater environments, temperate and tropical climes, constant and variable temperature regimes, and laboratory and field studies. The GDD demonstrates explanatory power across large spatial scales, e.g., 93% of the variation in LaD for age-2 to -4 Atlantic cod (Gadus morhua) across their entire range (17 stocks) is explained by one simple GDD function. Moreover, GDD can explain much of the variation in fish egg development time and in aquatic invertebrate (crab) size-at-age. Our analysis extends the well-established and physiologically relevant GDD metric to fish where, relative to conventional time-based methods, it provides greater explanatory power.Résumé : Le taux de croissance des ectothermes, dont celui de la plupart des poissons, est fonction de la température. Depuis des décennies, les spécialistes l'agriculture (270+ ans) et de l'entomologie (45+ ans) reconnaissent que la sommation thermique, connue sous le nom de degré-jour de croissance (GDD, EC·jour), permet de prédire de façon fiable la croissance et le développement. Les chercheurs en ichtyologie et en pêcheries tardent à reconnaître à grande échelle la puissance de GDD pour expliquer la croissance et le développement chez les poissons. Nous démontrons que la longueur en fonction du jour (LaD), la plupart des cas avant la maturation, est une solide fonction linéaire de la métrique GDD qui peut expliquer >92 % de la variation de LaD dans 41 séries de données représentant neuf espèces de poissons et tirées de milieux marins et d'eau douce, de climats tempérés et tropicaux, de régimes thermiques constants et variables et d'études de laboratoire et de terrain. La métrique GDD possède une pouvoir d'explication qui s'étend sur de grandes échelles spatiales; par exemple, une simple fonction GDD rend compte de 93 % de la variation de LaD chez des morues franches (Gadus morhua) d'âges 2-4 sur l'ensemble de leur répartition (17 stocks). De plus, GDD peut expliquer une grande partie de la variation du temps de développement des oeufs de poissons et de la taille en fonction de l'âge chez les invertébrés aquatiques (crabes). Notre analyse étend aux poissons l'utilisation de la métrique GDD, déjà bien établie et d'intérêt physiologique; cette métrique possède d'ailleurs un pouvoir explicatif plus important que les autres méthodes basées sur le temps.[Traduit par la Rédaction] Neuheimer and Taggart 385

The size of an individual organism is a key trait to characterize its physiology and feeding ecology. Size-based scaling laws may have a limited size range of validity or undergo a transition from one scaling exponent to another at some characteristic size. We collate and review data on size-based scaling laws for resource acquisition, mobility, sensory range, and progeny size for all pelagic marine life, from bacteria to whales. Further, we review and develop simple theoretical arguments for observed scaling laws and the characteristic sizes of a change or breakdown of power laws. We divide life in the ocean into seven major realms based on trophic strategy, physiology, and life history strategy. Such a categorization represents a move away from a taxonomically oriented description toward a trait-based description of life in the oceans. Finally, we discuss life forms that transgress the simple size-based rules and identify unanswered questions.