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The southern North Sea holds the world's highest concentration of offshore wind farms (OWFs). Northern gannets (Morus bassanus), a species considered at high risk from OWF impacts, show a strong seasonal peak there in November, but it is unclear which populations and age classes are most at risk of collision with wind turbines. We tagged adult and juvenile gannets at the world's largest colony (Bass Rock) and reviewed two sources of survey data for different age classes to study their movements through southern North Sea waters. Tracked birds showed peak numbers in the southern North Sea in mid-October, with much smaller numbers there during November. Adults were distributed throughout the area, including waters close to OWFs, whereas juveniles were confined to the coast. Survey data indicated high proportions of immature gannets in southern North Sea waters, suggesting higher collision risk than for adults. Gannets present in November may be predominantly from colonies further north than Bass Rock. • Offshore wind farms in the southern North Sea pose a threat for migrating gannets. • Environmental impact assessments need data on ages and populations at risk. • We provide insights through combining tracking and survey data. • Adults are more at risk than juveniles, whose migration paths are more coastal. • Gannets seen later in the year are likely migrating from colonies further north. [ABSTRACT FROM AUTHOR]

Ferritin-like carboxylate-bridged non-heme diiron enzymes activate O 2 for a variety of difficult reactions throughout nature. These reactions often begin by abstraction of hydrogen from strong C H bonds. The enzymes activate O 2 at their diferrous cofactors to form canonical diferric peroxo intermediates, with a range of possible coordination modes. Herein, we explore the ability of high-energy resolution fluorescence detected X-ray absorption spectroscopy (HERFD XAS) to provide insight into the nature of peroxo level intermediates in non-heme diiron proteins. Freeze quenched (FQ) peroxo intermediates from p -aminobenzoate N-oxygenase (AurF), aldehyde-deformylating oxygenase (ADO), and the β subunit of class Ia ribonucleotide reductase from Escherichia coli (Ec β) are investigated. All three intermediates are proposed to adopt different peroxo binding modes, and each exhibit different Fe Kα HERFD XAS pre-edge features and intensities. As these FQ-trapped samples consist of multiple species, deconvolution of HERFD XAS spectra based on speciation, as determined by Mössbauer spectroscopy, is also necessitated - yielding 'pure' diferric peroxo HERFD XAS spectra from dilute protein samples. Finally, the impact of a given peroxo coordination mode on the HERFD XAS pre-edge energy and intensity is evaluated through time-dependent density functional theory (TDDFT) calculations of the XAS spectra on a series of hypothetical model complexes, which span a full range of possible peroxo coordination modes to a diferric core. The utility of HERFD XAS for future studies of enzymatic intermediates is discussed. Reference high-resolution X-ray absorption spectra (XAS) of three freeze-quenched non-heme peroxodiiron(III) enzyme intermediates are obtained by deconvolution of XAS aided by Mössbauer quantification. Numerous peroxodiiron(III) motifs are explored computationally by time-dependent density functional theory calculations of pre-edge XAS features, where systematic trends for peroxo core motifs are assigned. Unlabelled Image • High-resolution X-ray absorption spectra of three peroxodiiron(III) enzymatic intermediates • Demonstration of X-ray absorption spectral deconvolution by Mössbauer spectroscopy • Use of pre-edge transitions and assignments by time-dependent density functional theory [ABSTRACT FROM AUTHOR]

There is a pressing need to quantify the risks of renewable energy developments such as offshore wind farms for protected populations. However, assessments are often based on incomplete data, or fail to consider variation in risk between sexes and at different times of year. We tracked northern gannets foraging from the world's largest colony (Bass Rock, Scotland) across five consecutive breeding seasons. We examine how seasonal and sex differences in behaviour affect the collision risk from planned and operational wind farms within their foraging range and assess the likely consequences for long-term population viability. Both sexes made shorter trips during chick-rearing than prior to chick-hatching, spent a greater proportion of time within wind farm sites and had an eight times greater potential collision risk during chick-rearing. Females made longer trips than males at both these times of year, flew higher and spent more time within wind farm sites, leading to three times greater collision risk for females. After accounting for the potential additional mortality from collisions, and assuming that the death of a parent also led to the loss of its offspring, the breeding population was projected to increase by 3.57% (95% CI: 2.16–5.15%) per year, compared with 6.56% (95% CI: 4.59–8.73%) in the absence of turbines, suggesting a negligible effect on population viability. However, additional mortality could result in greater immigration from neighbouring colonies, potentially affecting their viability and highlighting a need for research within a metapopulation framework to assess the impacts of offshore wind developments on vulnerable species across multiple connected sites. • Offshore windfarms may affect seabird populations through collisions with turbines. • We examined seasonal and sex specific collision risk at world's largest gannet colony. • Collision risk was highest among females rearing chicks. • Predicted collision mortality will slow population growth but not cause it to decline. • However, greater immigration from neighbouring colonies could affect their viability. [ABSTRACT FROM AUTHOR]