Population Connectivity and Phylogeography of a Coastal Fish, Atractoscion aequidens (Sciaenidae), across the Benguela Current Region: Evidence of an Ancient Vicariant Event

Contemporary patterns of genetic diversity and population connectivity within species can be influenced by both historical and contemporary barriers to gene flow. In the marine environment, present day oceanographic features such as currents, fronts and upwelling systems can influence dispersal of eggs/larvae and/juveniles/adults, shaping population substructuring. The Benguela Current system in the southeastern Atlantic is one of the oldest upwelling systems in the world, and provides a unique opportunity to investigate the relative influence of contemporary and historical mechanisms shaping the evolutionary history of warm-temperate fish species. Using the genetic variation in the mitochondrial DNA Control Region and eight nuclear microsatellite DNA loci, we identified the presence of two highly divergent populations in a vagile and warm-temperate fish species, Atractoscion aequidens, across the Benguela region. The geographical distributions of the two populations, on either side of the perennial upwelling cell, suggest a strong correlation between the oceanographic features of the system and the breakdown of gene flow within this species. Genetic divergence (mtDNA φ (ST) = 0.902, microsatellite F (ST) = 0.055: probability of genetic homogeneity for either marker = p<0.001), absence of migrants (less than 1% per generation) between populations and coalescent estimates of time since most recent common ancestor suggest that the establishment of the main oceanographic features of the system (2 million years ago), particularly the strengthening and position of the perennial upwelling cell, is the most likely mechanism behind the observed isolation. Concordance between mitochondrial and nuclear genetic markers indicates that isolation and divergence of the northern and southern Benguela populations of A. aequidens occurred deep in the past and has continued to the present day. These findings suggest that the Benguela Current system may constitute an ancient and impermeable barrier to gene flow for warm-temperate fish species

Molecular genetic, life-history and morphological variation in a coastal warm-temperature sciaenid fish:Evidence for an upwelling-driven speciation event

The marine environment is punctuated by biogeographical barriers that limit dispersal and gene flow in otherwise widespread species (Teske et al., 2011a,b; Briggs & Bowen, 2012; Luiz et al., 2012). These barriers may be physical obstacles such as landmasses (e.g. Isthmus of Panama) or less intuitive features such as deep water (Lessios et al., 2003), freshwater outflows (Floeter et al., 2008) or oceanographic features (Shaw et al., 2004; Galarza et al., 2009; von der Heyden et al., 2011). Upwelling cells and sea surface temperature (SSTs) gradients in particular are known to disrupt gene flow, leading to divergence of allopatric populations and species (Waters & Roy, 2004; Teske et al., 2011a; Henriques et al., 2012, 2014, 2015). However, as oceanographic features are seldom permanent and frequently subject to considerable environmental variability, many barriers often permit some level of permeability to dispersal (Floeter et al., 2008). Other processes may influence the persistence of differentiated allopatric taxa across such physical barriers (Bradbury et al., 2008), with ecological divergence (and diversifying selection) being reported as a major evolutionary process influencing the biogeographical distributions of marine species (Pelc et al., 2009; Teske et al., 2011a; Gaither et al., 2015)

Chemical and isotopic studies of the Wateranga layered mafic intrusion, southeast Queensland, Australia: magma sources and petrogenesis

This research was undertaken in order to thoroughly investigate the geochemistry of the Wateranga mafic layered intrusion in southeast Queensland, Australia. Nd-Sr-0 isotopic, whole-rock major and trace element and mineral chemical studies of the Wateranga intrusion were used to understand the nature of mantle sources and mafic magma genesis during a post-compressional extensional regime.The Wateranga layered mafic intrusion (28 km2) (&gt;500 m thick) is a tholeiitic, undeformed, unmetamorphosed, Permo-Triassic layered gabbroic pluton intruded into the Late Carboniferous Goodnight beds of the Goodnight Block in southeast Queensland. The intrusion mainly consists of gabbro and norite, associated with subordinate amounts of troctolite, anorthosite and orthopyroxenite, and rare picrite. Olivine gabbro is the dominant rock type of the intrusion. The whole-rock Sm-Nd isochron yields an age of 261±21 Ma. Petrographic, mineral chemical, whole-rock geochemical and Nd-Sr-0 isotopic data have been used to divide the intrusion into Lower, Middle and Upper Zones, which are interpreted as reflecting magma chamber replenishment. Although the general crystallization order of minerals is olivine, plagioclase, clinopyroxene, orthopyroxene, Fe-Ti oxides, hornblende and biotite, considerable differences exist between the Zones. The observed changes in the crystallization order between the Zones reveal that a single parental magma was inadequate to explain the data. The common differentiation indices, such as An content of plagioclase, Mg#s of olivine, clinopyroxene, orthopyroxene and whole-rocks, and the whole-rock concentrations of various incompatible trace elements (Zr, Y, Nb, La, Ba, Rb, Sr, and Nd) and Nd-Sr-0 isotopic compositions, all vary widely with stratigraphic depth and display abrupt shifts at the Zone boundaries, indicating open-system addition of new mafic magma. Litho- and chemo- stratigraphic analyses of the Wateranga intrusion show that it is the product of at least three major magma pulses.500 m thick) is a tholeiitic, undeformed, unmetamorphosed, Permo-Triassic layered gabbroic pluton intruded into the Late Carboniferous Goodnight beds of the Goodnight Block in southeast Queensland. The intrusion mainly consists of gabbro and norite, associated with subordinate amounts of troctolite, anorthosite and orthopyroxenite, and rare picrite. Olivine gabbro is the dominant rock type of the intrusion. The whole-rock Sm-Nd isochron yields an age of 261±21 Ma. Petrographic, mineral chemical, whole-rock geochemical and Nd-Sr-0 isotopic data have been used to divide the intrusion into Lower, Middle and Upper Zones, which are interpreted as reflecting magma chamber replenishment. Although the general crystallization order of minerals is olivine, plagioclase, clinopyroxene, orthopyroxene, Fe-Ti oxides, hornblende and biotite, considerable differences exist between the Zones. The observed changes in the crystallization order between the Zones reveal that a single parental magma was inadequate to explain the data. The common differentiation indices, such as An content of plagioclase, Mg#s of olivine, clinopyroxene, orthopyroxene and whole-rocks, and the whole-rock concentrations of various incompatible trace elements (Zr, Y, Nb, La, Ba, Rb, Sr, and Nd) and Nd-Sr-0 isotopic compositions, all vary widely with stratigraphic depth and display abrupt shifts at the Zone boundaries, indicating open-system addition of new mafic magma. Litho- and chemo- stratigraphic analyses of the Wateranga intrusion show that it is the product of at least three major magma pulses.Mineral chemical and whole-rock geochemical data indicate that fractional crystallization played an important role in the magmatic processes. However, sharp discontinuities and contrasting fractionation trends between the individual stratigraphic Zones of the intrusion suggest polycyclic fractionation of three major batches of magma. Fractionation followed tholeiitic trends with iron enrichment in the liquids. Rare earth element distributions indicate more than 5% partial melting of the mantle source with limited amounts of residual garnet. Finely disseminated sulphides occur throughout the intrusion. Textural and compositional evidence indicate that the disseminated Fe-Ni-Cu sulphides and platinum group elements are of magmatic origin.Microprobe analyses of coexisting clinopyroxene and orthopyroxene in different rocks of the intrusion provide consistent P-T data defining the magmatic crystallization condition as 1057 - 927 °C. During the course of crystallization pressure probably was greater than 2 and less than 4 kbar. Whole-rock initial εNd (3.26 - 6.44) and initial 87Sr/86Sr (0.7026 - 0.7049) compositions, chondrite normalized REE patterns and the variation trend of anorthite content of plagioclase versus the forsterite content of olivine precludes an arc-related magma source. The composition and geological setting of the intrusion are consistent with emplacement in a post-subduction extensional tectonic environment.The parental magmas to the Wateranga intrusion are olivine tholeiitic, derived from an asthenospheric mantle source in response to lithospheric extension during the Permo-Triassic (245±8Ma). Olivine tholeiitic magma, already contaminated by lower continental crust, was initially pooled in late Carboniferous sediments where the magma chamber evolved by fractional crystallization and periodic replenishment. Crustal assimilation was limited (2 to 8%)

Ocean warming, a rapid distributional shift, and the hybridization of a coastal fish species

Despite increasing awareness of large-scale climate-driven distribution shifts in the marine environment, no study has linked rapid ocean warming to a shift in distribution and consequent hybridization of a marine fish species. This study describes rapid warming (0.8 °C per decade) in the coastal waters of the Angola-Benguela Frontal Zone over the last three decades and a concomitant shift by a temperature sensitive coastal fish species (Argyrosomus coronus) southward from Angola into Namibia. In this context, rapid shifts in distribution across Economic Exclusive Zones will complicate the management of fishes, particularly when there is a lack of congruence in the fisheries policy between nations. Evidence for recent hybridization between A. coronus and a congener, A. inodorus, indicate that the rapid shift in distribution of A. coronus has placed adults of the two species in contact during their spawning events. Ocean warming may therefore revert established species isolation mechanisms and alter the evolutionary history of fishes. While the consequences of the hybridization on the production of the resource remain unclear, this will most likely introduce additional layers of complexity to their management

Intensive HST, RXTE and ASCA Monitoring of NGC 3516: Evidence Against Thermal Reprocessing

During 1998 April 13-16, NGC 3516 was monitored almost continuously with HST for 10.3 hr in the UV and 2.8 d in the optical, and simultaneous RXTE and ASCA monitoring covered the same period. The X-rays were strongly variable with the soft (0.5-2 keV) showing stronger variations (~65% peak-to-peak) than the hard (2-10 keV; ~50% peak-to-peak). The optical continuum showed much smaller but highly significant variations: a slow ~2.5% rise followed by a faster ~3.5% decline. The short UV observation did not show significant variability. The soft and hard X-ray light curves were strongly correlated with no significant lag. Likewise, the optical continuum bands (3590 and 5510 A) were also strongly correlated with no measurable lag above limits of <0.15 d. However no significant correlation or simple relationship could be found for the optical and X-ray light curves. These results appear difficult to reconcile with previous reports of correlations between X-ray and optical variations and of measurable lags within the optical band for some other Seyfert 1s. These results also present serious problems for "reprocessing" models in which the X-ray source heats a stratified accretion disk which then reemits in the optical/ultraviolet: the synchronous variations within the optical would suggest that the emitting region is <0.3 lt-d across, while the lack of correlation between X-ray and optical variations would indicate, in the context of this model, that any reprocessing region must be >1 lt-d in size. It may be possible to resolve this conflict by invoking anisotropic emission or special geometry, but the most natural explanation appears to be that the bulk of the optical luminosity is generated by some other mechanism than reprocessing.Comment: 23 pages including 6 figures, accepted for publication in Ap

The association of female reproductive factors with glaucoma and related traits: A systematic review

TOPIC: This systematic review summarizes the existing evidence for the association between female reproductive factors (age at menarche, parity, oral contraceptive (OC) use, age at menopause, and postmenopausal hormone (PMH) use) and intraocular pressure (IOP) or open-angle glaucoma (OAG). CLINICAL RELEVANCE: Understanding the association between female reproductive factors and glaucoma may shed light on disease pathogenesis and aid clinical prediction and personalized treatment strategies. Importantly, some factors are modifiable which may lead to new therapies. METHODS: Two reviewers independently extracted articles in Medline, Embase, Cochrane Database of Systematic Reviews, and Cochrane Central Register of Controlled Trials databases to identify relevant studies. Eligibility criteria included studies with human subjects over 18 years of age; a measured exposure of at least one of the following: age at menarche, parity, OC use, age at menopause, PMH use; a measured outcome of either IOP or OAG; a cohort, case-control, cross-sectional or randomized-controlled trial design; and a reported measure of association including hazard, risk or odds ratio or mean difference with associated confidence intervals. RESULTS: We included a total of 27 studies. Substantial differences in study design, exposure and treatment levels, treatment duration and variable reporting precluded meaningful quantitative synthesis of the identified studies. Overall, relatively consistent associations between PMH use and lower IOP were identified. With respect to OAG, estrogen-only PMH use may be associated with lower OAG risk and this association may be modified by race. No significant associations were found with combined estrogen + progesterone PMH use. No strong associations between parity, or age at menarche and glaucoma were found, but a younger age at menopause was associated with increased glaucoma risk, and adverse associations were identified with longer duration of OC use, though no overall association with OC use was found. CONCLUSION: The association between PMH use and lower IOP/OAG risk is a potentially clinically relevant and modifiable risk factor and should be investigated further, although this needs to be interpreted in the context of a high risk of bias across included studies. There is a need for future research examining associations with IOP specifically, and how the relationship between genetic factors and OAG risk may be influenced by female reproductive factors

Alcohol, intraocular pressure and open-angle glaucoma: A systematic review and meta-analysis

TOPIC: This systematic review and meta-analysis summarizes the existing evidence for the association of alcohol use with intraocular pressure (IOP) and open-angle glaucoma (OAG). CLINICAL RELEVANCE: Understanding and quantifying these associations may aid clinical guidelines or treatment strategies and shed light on disease pathogenesis. The role of alcohol, a modifiable factor, in determining IOP and OAG risk may also be of interest from an individual or public health perspective. METHODS: The study protocol was pre-registered in the Open Science Framework Registries (https://osf.io/z7yeg). Eligible articles (as of 14 May 2021) from three databases (PubMed, Embase, Scopus) were independently screened and quality assessed by two reviewers. All case-control, cross-sectional and cohort studies reporting a quantitative effect estimate and 95% confidence interval (CI) for the association between alcohol use and either IOP or OAG were included. The evidence for the associations with both IOP and OAG were qualitatively summarized. Effect estimates for the association with OAG were pooled using random effects meta-analysis. Studies not meeting formal inclusion criteria for systematic review, but with pertinent results, were also appraised and discussed. Certainty of evidence was assessed using the GRADE framework. RESULTS: Thirty four studies were included in the systematic review. Evidence from 10 studies reporting an association with IOP suggest that habitual alcohol use is associated with higher IOP and prevalence of ocular hypertension (IOP >21mmHg), although absolute effect sizes were small. Eleven of 26 studies, comprising 173 058 participants, that tested for an association with OAG met inclusion criteria for meta-analysis. Pooled effect estimates indicated a positive association between any use of alcohol and OAG (1.18; 95% CI, 1.02-1.36; p=0.03; I2=40.5%), with similar estimates for both prevalent and incident OAG. The overall GRADE certainty of evidence was very low. CONCLUSION: While this meta-analysis suggests a harmful association between alcohol use and OAG, our results should be interpreted cautiously given the weakness and heterogeneity of the underlying evidence base, the small absolute effect size and the borderline statistical significance. Nonetheless, these findings may be clinically relevant and future research should focus on improving the quality of evidence

Deep Ocular Phenotyping Across Primary Open-Angle Glaucoma Genetic Burden

IMPORTANCE: Better understanding of primary open-angle glaucoma (POAG) genetics could enable timely screening and promote individualized disease risk prognostication. OBJECTIVE: To evaluate phenotypic features across genetic burden for POAG. DESIGN, SETTING, AND PARTICIPANTS: This was a cross-sectional, population-based study conducted from 2006 to 2010. Included participants were individuals from the UK Biobank aged 40 to 69 years. Individuals with non-POAG forms of glaucoma were excluded from the analysis. Data were statistically analyzed from October 2022 to January 2023. MAIN OUTCOMES AND MEASURES: POAG prevalence based on structural coding, self-reports, and glaucoma-related traits. RESULTS: Among 407 667 participants (mean [SD] age, 56.3 [8.1] years; 219 183 majority sex [53.8%]) were 14 171 POAG cases. Area under receiver operating characteristic curve for POAG detection was 0.748 in a model including polygenic risk score (PRS), age, sex, and ancestry. POAG prevalence in the highest decile of PRS was 7.4% (3005 of 40 644) vs 1.3% (544 of 40 795) in lowest decile (P < .001). A 1-SD increase in PRS was associated with 1.74 times higher odds of POAG (95% CI, 1.71-1.77), a 0.61-mm Hg increase in corneal-compensated intraocular pressure (IOP; 95% CI, 0.59-0.64), a -0.09-mm Hg decrease in corneal hysteresis (95% CI, -0.10 to -0.08), a 0.08-mm Hg increase in corneal resistance factor (95% CI, 0.06-0.09), and a -0.08-diopter decrease in spherical equivalent (95% CI, -0.11 to -0.07; P < .001 for all). A 1-SD increase in PRS was associated with a thinning of the macula-region retinal nerve fiber layer (mRNFL) of 0.14 μm and macular ganglion cell complex (GCC) of 0.26 μm (P < .001 for both). In the subset of individuals with fundus photographs, a 1-SD increase in PRS was associated with 1.42 times higher odds of suspicious optic disc features (95% CI, 1.19-1.69) and a 0.013 increase in cup-disc ratio (CDR; 95% CI, 0.012-0.014; P < .001 for both). A total of 22 of 5193 fundus photographs (0.4%) in decile 10 had disc hemorrhages, and 27 of 5257 (0.5%) had suspicious optic disc features compared with 9 of 5158 (0.2%) and 10 of 5219 (0.2%), respectively, in decile 1 (P < .001 for both). CDR in decile 10 was 0.46 compared with 0.41 in decile 1 (P < .001). CONCLUSION AND RELEVANCE: Results suggest that PRS identified a group of individuals at substantially higher risk for POAG. Higher genetic risk was associated with more advanced disease, namely higher CDR and corneal-compensated IOP, thinner mRNFL, and thinner GCC. Associations with POAG PRS and corneal hysteresis and greater prevalence of disc hemorrhages were identified. These results suggest that genetic risk is an increasingly important parameter for risk stratification to consider in clinical practice

World squid fisheries

Peer reviewedPublisher PD

The association between serum lipids and intraocular pressure in two large UK cohorts

PURPOSE: Serum lipids are modifiable, routinely collected blood tests associated with cardiovascular health. We examined the association of commonly collected serum lipid measures (total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein (LDL-C) and triglycerides (TG)) with intraocular pressure (IOP). DESIGN: Cross-sectional study in the UK Biobank and EPIC-Norfolk cohorts. PARTICIPANTS: We included 94 323 participants of UK Biobank (mean age 57 years) and 6 230 participants of EPIC-Norfolk (mean age 68 years) with data on TC, HDL-C, LDL-C, TG collected between 2006-2009. METHODS: Multivariable linear regression adjusting for demographic, lifestyle, anthropometric, medical and ophthalmic covariables was used to examine the associations of serum lipids with IOPcc. MAIN OUTCOME MEASURES: IOPcc. RESULTS: Higher levels of TC, HDL-C and LDL-C were independently associated with higher IOPcc in both cohorts after adjustment for key demographic, medical and lifestyle factors. For each standard deviation increase in TC, HDL-C, and LDL-C, IOPcc (mmHg) was higher by 0.09 (95% CI: 0.06-0.11; P<0.001), 0.11 (95% CI 0.08-0.13; P<0.001), 0.07 (95% CI: 0.05-0.09, P<0.001), respectively in the UK Biobank cohort. In the EPIC-Norfolk cohort, each additional standard deviation in TC, HDL-C, and LDL-C was associated with a higher IOPcc (mmHg) by 0.19 (95% CI 0.07-0.31, P=0.001), 0.14 (95% CI 0.03-0.25, P=0.016), and 0.17 (95% CI 0.06-0.29, P=0.003). An inverse association between TGs and IOP in the UK Biobank (-0.05, 95% CI -0.08 to -0.03, P<0.001) was not replicated in the EPIC cohort (P=0.30). CONCLUSION: Our findings suggest that serum TC, HDL-C and LDL-C are positively associated with IOP in two UK cohorts and TGs may be negatively associated. Future research is required to assess whether these associations are causal in nature