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"Abstract Climate change can affect organisms both directly via physiological stress and indirectly via changing relationships among species. However, we do not fully understand how changing interspecific relationships contribute to community- and ecosystem-level responses to environmental forcing. I used experiments and spatial and temporal comparisons to demonstrate that warming substantially reduces predator-free space on rocky shores. The vertical extent of mussel beds decreased by 51% in 52 years, and reproductive populations of mussels disappeared at several sites. Prey species were able to occupy a hot, extralimital site if predation pressure was experimentally reduced, and local species richness more than doubled as a result. These results suggest that anthropogenic climate change can alter interspecific interactions and produce unexpected changes in species distributions, community structure, and diversity. "

1 The carbon dioxide system in seawater: equilibrium chemistry and measurements 1.1 Introduction 1.2 Basic chemistry of carbon dioxide in seawater 1.3 The definition and measurement of pH in seawater 1.4 Implications of other acid-base equilibria in seawater on seawater alkalinity 1.5 Choosing the appropriate measurement techniques 1.6 Conclusions and recommendations 2 Approaches and tools to manipulate the carbonate chemistry 3 Atmospheric CO2 targets for ocean acidification perturbation experiments 4 Designing ocean acidification experiments to maximise inference 5 Bioassays, batch culture and chemostat experimentation 6 Pelagic mesocosms 7 Laboratory experiments and benthic mesocosm studies 8 In situ perturbation experiments: natural venting sites, spatial/temporal gradients in ocean pH, manipulative in situ p(CO2) perturbations 9 Studies of acid-base status and regulation 9.1 Introduction 9.2 Fundamentals of acid-base regulation 9.3 Measurement of pH, total CO2 and non-bicarbonate buffer values 9.4 Compartmental measurements: towards a quantitative picture 9.5 Overall suggestions for improvements 10 Studies of metabolic rate and other characters across life stages 10.1 Introduction 10.2 Definition of a frame of reference: studying specific characters across life stages 10.3 Approaches and methodologies: metabolic studies 10.4 Study of early life stages 10.5 Techniques for oxygen analyses 10.6 Overall suggestions for improvements 10.7 Data reporting 10.8 Recommendations for standards and guidelines 11 Production and export of organic matter 12 Direct measurements of calcification rates in planktonic organisms 13 Measurements of calcification and dissolution of benthic organisms and communities 14 Modelling considerations 15 Safeguarding and sharing ocean acidification data 15.1 Introduction 15.2 Sharing ocean acidification data 15.3 Safeguarding ocean acidification data 15.4 Harmonising ocean acidification data and metadata 15.5 Disseminating ocean

"Nitrogen (N2)-fixing microorganisms (diazotrophs) are an important source of biologically available fixed N in terrestrial and aquatic ecosystems and control the productivity of oligotrophic ocean ecosystems. We found that two major groups of unicellular N2-fixing cyanobacteria (UCYN) have distinct spatial distributions that differ from those of Trichodesmium, the N2-fixing cyanobacterium previously considered to be the most important contributor to open-ocean N2 fixation. The distributions and activity of the two UCYN groups were separated as a function of depth, temperature, and water column density structure along an 8000-kilometer transect in the South Pacific Ocean. UCYN group A can be found at high abundances at substantially higher latitudes and deeper in subsurface ocean waters than Trichodesmium. These findings have implications for the geographic extent and magnitude of basin-scale oceanic N2 fixation rates. "

"Spatial diversity gradients are a pervasive feature of life on Earth. We examined a global ocean circulation, biogeochemistry, and ecosystem model that indicated a decrease in phytoplankton diversity with increasing latitude, consistent with observations of many marine and terrestrial taxa. In the modeled subpolar oceans, seasonal variability of the environment led to competitive exclusion of phytoplankton with slower growth rates and lower diversity. The relatively weak seasonality of the stable subtropical and tropical oceans in the global model enabled long exclusion time scales and prolonged coexistence of multiple phytoplankton with comparable fitness. Superimposed on the decline in diversity seen from equator to pole were "hot spots" of enhanced diversity in some regions of energetic ocean circulation, which reflected lateral dispersal. "