A research agenda for seed-trait functional ecology

Trait-based approaches have improved our understanding of plant evolution, community assembly and ecosystem functioning. A major challenge for the upcoming decades is to understand the functions and evolution of early life-history traits, across levels of organization and ecological strategies. Although a variety of seed traits are critical for dispersal, persistence, germination timing and seedling establishment, only seed mass has been considered systematically. Here we suggest broadening the range of morphological, physiological and biochemical seed traits to add new understanding on plant niches, population dynamics and community assembly. The diversity of seed traits and functions provides an important challenge that will require international collaboration in three areas of research. First, we present a conceptual framework for a seed ecological spectrum that builds upon current understanding of plant niches. We then lay the foundation for a seed-trait functional network, the establishment of which will underpin and facilitate trait-based inferences. Finally, we anticipate novel insights and challenges associated with incorporating diverse seed traits into predictive evolutionary ecology, community ecology and applied ecology. If the community invests in standardized seed-trait collection and the implementation of rigorous databases, major strides can be made at this exciting frontier of functional ecology.Commonwealth Scientific and Industrial Research Organisation. Grant Number: R‐90470‐0

Subcortical volumes across the lifespan: data from 18,605 healthy individuals aged 3-90 years

Age has a major effect on brain volume. However, the normative studies available are constrained by small sample sizes, restricted age coverage and significant methodological variability. These limitations introduce inconsistencies and may obscure or distort the lifespan trajectories of brain morphometry. In response, we capitalized on the resources of the Enhancing Neuroimaging Genetics through Meta-Analysis (ENIGMA) Consortium to examine age-related trajectories inferred from cross-sectional measures of the ventricles, the basal ganglia (caudate, putamen, pallidum, and nucleus accumbens), the thalamus, hippocampus and amygdala using magnetic resonance imaging data obtained from 18,605 individuals aged 3-90 years. All subcortical structure volumes were at their maximum value early in life. The volume of the basal ganglia showed a monotonic negative association with age thereafter; there was no significant association between age and the volumes of the thalamus, amygdala and the hippocampus (with some degree of decline in thalamus) until the sixth decade of life after which they also showed a steep negative association with age. The lateral ventricles showed continuous enlargement throughout the lifespan. Age was positively associated with inter-individual variability in the hippocampus and amygdala and the lateral ventricles. These results were robust to potential confounders and could be used to examine the functional significance of deviations from typical age-related morphometric patterns.Education and Child Studie

Cadmium uptake by marine micro-organisms in the English Channel and Celtic Sea

A series of shipboard experiments using the radiotracer 109Cd investigated the role of phytoplankton and bacteria in the uptake of dissolved Cd in the English Channel and Celtic Sea. The results demonstrate that Cd uptake is related to rates of primary production and bacterial numbers. Statistical analysis of plankton species abundance infer that Rhizosolenia, Chaetoceros and Pseudonitzschia diatom species are largely responsible for the higher Cd uptake observed in the >5 ?m size fraction during a diatom-dominated spring bloom. Total Cd uptake rates during winter non-bloom conditions were between 0.04 and 0.29 pmol l–1 h–1, and increased to between 0.43 and 1.23 pmol l–1 h–1 during diatom bloom conditions. These uptake rates are consistent with the seasonal surface depletion of Cd reported in the Celtic Sea and attributed to uptake by phytoplankton bloom material. A calculated Cd:C ratio of 3.1 ?mol mol–1 for natural plankton samples of the Celtic Sea agrees well with results of previous culture studies, which have reported ratios between 0.1 and 5.0 ?mol mol–1 for the coastal diatoms Thalassiosira weissflogii and T. pseudonana. Cd uptake was also linearly related to bacterial numbers, which was attributed to surface adsorption of Cd ions onto bacterial particles which have relatively high specific surface areas. These results demonstrate surface adsorption of Cd onto bacterial surfaces, and other biogenic non-living particles, i.e. ‘passive Cd uptake’, which is significantly augmented during a spring diatom bloom