Iron biogeochemistry across marine systems progress from the past decade

Based on an international workshop (Gothenburg, 14–16 May 2008), this review article aims to combine interdisciplinary knowledge from coastal and open ocean research on iron biogeochemistry. The major scientific findings of the past decade are structured into sections on natural and artificial iron fertilization, iron inputs into coastal and estuarine systems, colloidal iron and organic matter, and biological processes. Potential effects of global climate change, particularly ocean acidification, on iron biogeochemistry are discussed. The findings are synthesized into recommendations for future research areas

Beyond the Lines: Exploring the Impact of Adverse Childhood Experiences on NCAA Student-Athlete Health

Emerging research has highlighted a link between adverse childhood experiences (ACEs) and various health concerns experienced by NCAA student-athletes. Building on prior work (Kaier, Cromer, Davis, & Strunk, 2015), we hypothesized that ACEs would significantly predict student-athletes’ biopsychosocial (BPS) health and that spirituality would serve as a protective factor against the effect of ACEs on BPS health outcomes. Division I, II, and III NCAA student-athletes (N = 477) representing 20 sports across 53 universities completed an online quantitative survey (k = 133) that assessed for ACEs, injury/physical health concerns, anxiety, depression, stress, social support, substance use, and spirituality. Nearly two-thirds (64.5%) of student-athletes endorsed at least one ACE. Structural Equation Models (SEMs) yielded significant positive relationships between ACEs and anxiety, depression, perceived stress, injury/health problems, and substance use, and a negative relationship with social support while controlling for sex, race, school, and division. Additionally, spirituality had a significant negative effect on anxiety, depression, perceived stress, injury/health problems, and substance use, and a positive effect on social support. SEM moderation analyses indicated that spirituality only moderated the relationship between ACEs and substance use. Specifically, at average and high levels of spirituality, the relationship between ACEs and substance use was stronger. Clinical implications, study limitations, and future research directions are discussed

Statistical Mechanics of Horizontal Gene Transfer in Evolutionary Ecology

The biological world, especially its majority microbial component, is strongly interacting and may be dominated by collective effects. In this review, we provide a brief introduction for statistical physicists of the way in which living cells communicate genetically through transferred genes, as well as the ways in which they can reorganize their genomes in response to environmental pressure. We discuss how genome evolution can be thought of as related to the physical phenomenon of annealing, and describe the sense in which genomes can be said to exhibit an analogue of information entropy. As a direct application of these ideas, we analyze the variation with ocean depth of transposons in marine microbial genomes, predicting trends that are consistent with recent observations using metagenomic surveys.Comment: Accepted by Journal of Statistical Physic

Stability of dissolved and soluble Fe(II) in shelf sediment pore waters and release to an oxic water column

Shelf sediments underlying temperate and oxic waters of the Celtic Sea (NW European Shelf) were found to have shallow oxygen penetrations depths from late spring to late summer (2.2–5.8 mm below seafloor) with the shallowest during/after the spring-bloom (mid-April to mid-May) when the organic carbon content was highest. Sediment porewater dissolved iron (dFe, 85%) consisted of Fe(II) and gradually increased from 0.4 to 15 μM at the sediment surface to ~100–170 µM at about 6 cm depth. During the late spring this Fe(II) was found to be mainly present as soluble Fe(II) (>85% sFe, 7 h. Iron(II) oxidation experiments in core top and bottom waters also showed removal from solution but at rates up to 5-times slower than predicted from theoretical reaction kinetics. These data imply the presence of ligands capable of complexing Fe(II) and supressing oxidation. The lower oxidation rate allows more time for the diffusion of Fe(II) from the sediments into the overlying water column. Modelling indicates significant diffusive fluxes of Fe(II) (on the order of 23–31 µmol m−2 day−1) are possible during late spring when oxygen penetration depths are shallow, and pore water Fe(II) concentrations are highest. In the water column this stabilised Fe(II) will gradually be oxidised and become part of the dFe(III) pool. Thus oxic continental shelves can supply dFe to the water column, which is enhanced during a small period of the year after phytoplankton bloom events when organic matter is transferred to the seafloor. This input is based on conservative assumptions for solute exchange (diffusion-reaction), whereas (bio)physical advection and resuspension events are likely to accelerate these solute exchanges in shelf-seas

Shipboard techniques based on flow injection analysis for measuring dissolved Fe, Mn and Al in seawater

info:eu-repo/semantics/publishe