This is a tribute to a truly inspirational plant biologist, Prof. John A. Raven, FRS, FRSE (25th June 1941– 23rd May 2024), who died at the age of 82. He was a leader in the field of evolution and physiology of algae and land plants. His research touched on many areas including photosynthesis, ion transport, carbon utilisation, mineral use, such as silicon, iron and molybdenum, the evolution of phytoplankton, the evolution of...

The goal of the Caenorhabditis Intervention Testing Program is to identify robust and reproducible pro-longevity interventions that are efficacious across genetically diverse cohorts in the Caenorhabditis genus. The project design features multiple experimental replicates collected by three different laboratories. Our initial effort employed fully manual survival assays. With an interest in increasing throughput, we explored a...

Understanding the cellular and molecular responses of stony corals to ocean acidification is key to predicting their ability to calcify under projected high CO 2 conditions. Of specific interest are the links between biomineralization proteins and the precipitation of new calcium carbonate (CaCO 3 ), which potentially can provide a better understanding of the biomineralization process. We have assessed the effects of increased...

We measured the light dependence of gross photosynthesis and oxygen uptake rates by membrane inlet mass spectrometry in two open ocean regions: the Amundsen Sea (Antarctica), dominated by Phaeocystis antarctica , and the North Atlantic, dominated by Emiliania huxleyi . In the North Atlantic, respiration was independent of irradiance and was higher than the gross photosynthetic rate at all irradiances. In contrast, in the Amund...

Trait‐based approaches to community structure are increasingly used in terrestrial ecology. We show that such an approach, augmented by a mechanistic analysis of trade‐offs among functional traits, can be successfully used to explain community composition of marine phytoplankton along environmental gradients. Our analysis of literature on major functional traits in phytoplankton, such as parameters of nutrient‐dependent growth...

The dissolution of aragonite particles in the ocean primarily depends on the degree of undersaturation of seawater with respect to that mineral. Most of the upper Atlantic Ocean, particularly north of 308S and at depths of less than 2000 m, is supersaturated with respect to aragonite, whereas much of the deep Atlantic is undersaturated. Here we report, for the first time, shallow layers of aragonite‐undersaturated water betwee...

Fluorescent pigments in several Indo‐Pacific and Caribbean anthozoans have recently been identified as proteins related to the Green‐fluorescent protein (GFP) of the hydromedusa Aequorea victoria . Here we show that GFP is widely distributed in many Caribbean species. The fluorescence excitation and emission spectra for the pigment are similar to those reported elsewhere for coral and noncoral GFP and the fluorescence quantum...

Curiously, the benthic foraminifer, Nonionella stella , found in the upper 3 cm of sediments collected off California at a depth of ;600 m, retains chloroplasts. We examined the origin and physiological function of the organelles within the host cell. Transmission electron micrographs, fluorescence and absorption spectra, Western blots, and enzyme assays revealed that the chloroplasts were intact and retained functionality for...

Iron availability is suggested to be a primary factor limiting nitrogen fixation in the oceans. This hypothesis is principally based on costߚbenefit analyses of iron quotas in the dominant nitrogenߚfixing cyanobacteria, Trichodesmium spp., in the contemporary oceans. Although previous studies with Trichodesmium have indicated that iron availability enhanced nitrogen fixation and photosynthesis, no clear relationship has been r...