Regeneration of Fe(II) during EIFeX and SOFeX

Investigations into Fe(II) cycling during two Southern Ocean mesoscale iron enrichment experiments, SOFeX and EIFeX, clearly show the importance of Fe(II) to iron speciation during these experiments. In both cases the added Fe(II) persisted significantly longer than its expected oxidation time indicating a significant Fe reduction process at work. During EIFeX diel studies showed a strong photochemically induced cycle in Fe(II) production in sunlit surface waters. Our results suggest that the photochemical cycling of iron may also be important in unfertilized waters of the Southern Ocean

Guidance for reporting intervention development studies in health research (GUIDED) : an evidence-based consensus study

Objective: To improve the quality and consistency of intervention development reporting in health research. Design: This was a consensus exercise consisting of two simultaneous and identical three-round e-Delphi studies (one with experts in intervention development and one with wider stakeholders including funders, journal editors and public involvement members), followed by a consensus workshop. Delphi items were systematically derived from two preceding systematic reviews and a qualitative interview study. Participants: Intervention developers (n=26) and wider stakeholders (n=18) from the UK, North America and Europe participated in separate e-Delphi studies. Intervention developers (n=13) and wider stakeholders (n=13) participated in a 1-day consensus workshop. Results: e-Delphi participants achieved consensus on 15 reporting items. Following feedback from the consensus meeting, the final inclusion and wording of 14 items with description and explanations for each item were agreed. Items focus on context, purpose, target population, approaches, evidence, theory, guiding principles, stakeholder contribution, changes in content or format during the development process, required changes for subgroups, continuing uncertainties, and open access publication. They form the GUIDED (GUIDance for the rEporting of intervention Development) checklist, which contains a description and explanation of each item, alongside examples of good reporting. Conclusions: Consensus-based reporting guidance for intervention development in health research is now available for publishers and researchers to use. GUIDED has the potential to lead to greater transparency, and enhance quality and improve learning about intervention development research and practice

A luminescent whole-cell cyanobacterial bioreporter for measuring Fe availability in diverse marine environments

A Synechococcus sp. strain PCC 7002 Fe bioreporter was constructed containing the isiAB promoter fused to the Vibrio harveyi luxAB genes. Bioreporter luminescence was characterized with respect to the free ferric ion concentration in trace metal-buffered synthetic medium. The applicability of the Fe bioreporter to assess Fe availability in the natural environment was tested by using samples collected from the Baltic Sea and from the high-nutrient, low-chlorophyll subarctic Pacific Ocean. Parallel assessment of dissolved Fe and bioreporter response confirmed that direct chemical measurements of dissolved Fe should not be considered alone when assessing Fe availability to phytoplankton

A luminescent whole-cell cyanobacterial bioreporter for measuring Fe availability in diverse marine environments

A Synechococcus sp. strain PCC 7002 Fe bioreporter was constructed containing the isiAB promoter fused to the Vibrio harveyi luxAB genes. Bioreporter luminescence was characterized with respect to the free ferric ion concentration in trace metal-buffered synthetic medium. The applicability of the Fe bioreporter to assess Fe availability in the natural environment was tested by using samples collected from the Baltic Sea and from the high-nutrient, low-chlorophyll subarctic Pacific Ocean. Parallel assessment of dissolved Fe and bioreporter response confirmed that direct chemical measurements of dissolved Fe should not be considered alone when assessing Fe availability to phytoplankton

Physical mixing effects on iron biogeochemical cycling: FeCycle experiment

The effects of physical processes on the distribution, speciation, and sources/sinks for Fe in a high-nutrient low-chlorophyll (HNLC) region were assessed during FeCycle, a mesoscale SF6 tracer release during February 2003 (austral summer) to the SE of New Zealand. Physical mixing processes were prevalent during FeCycle with rapid patch growth (strain rate γ = 0.17–0.20 d−1) from a circular shape (50 km2) into a long filament of ∼400 km2 by day 10. Slippage between layers saw the patch-head overlying noninfused waters while the tail was capped by adjacent surface waters resulting in a SF6 maximum at depth. As the patch developed it entrained adjacent waters containing higher chlorophyll concentrations, but similar dissolved iron (DFe) levels, than the initial infused patch. DFe was low ∼60 pmol L−1 in surface waters during FeCycle and was dominated by organic complexation. Nighttime measurements of Fe(II) ∼20 pmol L−1 suggest the presence of Fe(II) organic complexes in the absence of an identifiable fast Fe(III) reduction process. Combining residence times and phytoplankton uptake fluxes for DFe it is cycled through the biota 140–280 times before leaving the winter mixed layer (WML). This strong Fe demand throughout the euphotic zone coupled with the low Fe:NO3 − (11.9 μmol:mol) below the ferricline suggests that vertical diffusion of Fe is insufficient to relieve chronic iron limitation, indicating the importance of atmospheric inputs of Fe to this region

Attending to design when developing complex health interventions: A qualitative interview study with intervention developers and associated stakeholders

Background: Guidance and frameworks exist to assist those developing health interventions but may offer limited discussion of ‘design’, the part of development concerned with generating ideas for and making decisions about an intervention’s content, format and delivery. The aim of this paper is to describe and understand the views and experiences of developers and associated stakeholders in relation to how design occurs in health intervention development. Methods: Semi-structured interviews were conducted with 21 people who had developed complex interventions to improve health and/or who were relevant stakeholders (e.g. funders and publishers of intervention development work), regarding their views, experiences and approaches to intervention design. Sampling was purposive in terms of maximising diversity. A thematic inductive analysis was conducted. Results: Approaches to design varied substantially between intervention developers. This contrasted with consistency in other activities undertaken during development, such as literature review. Design also posed more challenges than other parts of development. We identified six ‘modes’ of design: informed; negotiated; structured; delegated; ‘my baby’; and creative partnership. In understanding the differences between these different modes, and the challenges posed by intervention design, we identified three key themes: enabling creativity during the design process; working with different types of knowledge; and ‘stabilising’ (developing clear shared understandings of) the intervention development to enable design. Conclusions: Design has received less attention than other activities undertaken when developing interventions to improve health. Developers take a variety of approaches to design and often find it challenging. Guidance for intervention development in health has tended to see design as proceeding in a predictable and controlled manner from acquired knowledge. Our study suggests that design rarely reflects this rational ideal. Future guidance on intervention development in healthcare should support developers to work effectively with different types of knowledge, to help design progress more smoothly and to maximise creativity

Understanding successful development of complex health and healthcare interventions and its drivers from the perspective of developers and wider stakeholders: an international qualitative interview study

Objective: Identify how individuals involved in developing complex health and healthcare interventions (developers), and wider stakeholders in the endeavour, such as funders, define successful intervention development and what factors influence how interventions are developed. Design: In-depth interviews with developers and wider stakeholders to explore their views and experiences of developing complex health and healthcare interventions. Setting: Interviews conducted with individuals in the UK, Europe and North America. Participants: Twenty-one individuals were interviewed: 15 developers and 6 wider stakeholders. Seventeen participants were UK based. Results: Most participants defined successful intervention development as a process that resulted in effective interventions that were relevant, acceptable and could be implemented in real-world contexts. Accounts also indicated that participants aimed to develop interventions that end users wanted, and to undertake a development process that was methodologically rigorous and provided research evidence for journal publications and future grant applications. Participants’ ambitions to develop interventions that had real-world impact drove them to consider the intervention’s feasibility and long-term sustainability early in the development process. However, this process was also driven by other factors: the realities of resource-limited health contexts; prespecified research funder priorities; a reluctance to deviate from grant application protocols to incorporate evidence and knowledge acquired during the development process; limited funding to develop interventions and the need for future randomised controlled trials (RCTs) to prove effectiveness. Participants expressed concern that these drivers discouraged long-term thinking and the development of innovative interventions, and prioritised evaluation over development and future implementation. Conclusions: Tensions exist between developers’ goal of developing interventions that improve health in the real world, current funding structures, the limited resources within healthcare contexts, and the dominance of the RCT for evaluation of these interventions. There is a need to review funding processes and expectations of gold standard evaluation

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

Pathways of Superoxide (O2-) decay in the Eastern Tropical North Atlantic

Superoxide (O2-: IUPAC name dioxide (•1−)) is an important transient reactive oxygen species (ROS) in the ocean formed as an intermediate in the redox transformation of oxygen (O2) into hydrogen peroxide (H2O2) and vice versa. This highly reactive and very short-lived radical anion can be produced both via photochemical and biological processes in the ocean. In this paper we examine the decomposition rate of O2- throughout the water column, using new data collected in the Eastern Tropical North Atlantic (ETNA) Ocean. For this approach we applied a semi factorial experimental design, to identify and quantify the pathways of the major identified sinks in the ocean. In this work we occupied 6 stations, 2 on the West African continental shelf and 4 open ocean stations, including the CVOO time series site adjacent to Cape Verde. Our results indicate that in the surface ocean, impacted by Saharan aerosols and sediment resuspension, the main decay pathways for superoxide is via reactions with Mn(II) and organic matter