ALBERT

Description: Understanding how copepods may respond to ocean acidification (OA) is critical for risk assessments of ocean ecology and biogeochemistry. The perception that copepods are insensitive to OA is largely based on experiments with adult females. Their apparent resilience to increased carbon dioxide (pCO 2 ) concentrations has supported the view that copepods are ‘winners’ under OA. Here, we show that this conclusion is not robust, that sensitivity across different life stages is significantly misrepresented by studies solely using adult females. Stage-specific responses to pCO 2 (385–6000 μatm) were studied across different life stages of a calanoid copepod, monitoring for lethal and sublethal responses. Mortality rates varied significantly across the different life stages, with nauplii showing the highest lethal effects; nauplii mortality rates increased threefold when pCO 2 concentrations reached 1000 μatm (year 2100 scenario) with LC 50 at 1084 μatm pCO 2 . In comparison, eggs, early copepodite stages, and adult males and females were not affected lethally until pCO 2 concentrations ≥3000 μatm. Adverse effects on reproduction were found, with 〉35% decline in nauplii recruitment at 1000 μatm pCO 2 . This suppression of reproductive scope, coupled with the decreased survival of early stage progeny at this pCO 2 concentration, has clear potential to damage population growth dynamics in this species. The disparity in responses seen across the different developmental stages emphasizes the need for a holistic life-cycle approach to make species-level projections to climate change. Significant misrepresentation and error propagation can develop from studies which attempt to project outcomes to future OA conditions solely based on single life history stage exposures.

Description: Microplastic litter is a pervasive pollutant present in aquatic systems across the globe. A range of marine organisms have the capacity to ingest microplastics, resulting in adverse health effects. Developing methods to accurately quantify microplastics in productive marine waters, and those internalized by marine organisms, is of growing importance. Here we investigate the efficacy of using acid, alkaline and enzymatic digestion techniques in mineralizing biological material from marine surface trawls to reveal any microplastics present. Our optimized enzymatic protocol can digest 〉97% (by weight) of the material present in plankton-rich seawater samples without destroying any microplastic debris present. In applying the method to replicate marine samples from the western English Channel, we identified 0.27 microplastics m3. The protocol was further used to extract microplastics ingested by marine zooplankton under laboratory conditions. Our findings illustrate that enzymatic digestion can aid the detection of microplastic debris within seawater samples and marine biota. Scientific Reports 4 doi: 10.1038/srep04528

Description: Two geophysical onshore-offshore lines on the southern margin of Africa form the Agulhas-Karoo Geophysical Transect (AKGT) and cross prominent geological features such as the Karoo Basin, Cape Fold Belt (CFB) and the Beattie Magnetic Anomaly (BMA). Geophysical data acquired along this AKGTransect between 2004 and 2007 within the Inkaba yeAfrica (lyA) framework, provide the platform for constructing a deep crustal section (IyA-200501) for the centre 100 km of the western AKGT-transect in order to resolve these features at depth. We present a detailed deep crustal model constructed from the joint interpretation of: i. archive data comprising surface geology, aeromagnetic data, nearby deep boreholes, teleseismic receiver functions and regional seismic reflection profiles, and ii. line coincident newly acquired high-resolution geophysical data consisting of near vertical seismic reflection data, shallow P- and S-wave velocity data, wide-angle refraction data, high resolution magnetotelluric data and impedance spectroscopy measurements on borehole samples. Our model differentiates four components in the up to 45 km thick crust: 1. a ~2 to 5 km thick folded Karoo Supergroup, disrupted by low-angle thrust faults rooted in a zone of local décollements in the lower Ecca Group and resting paraconformably on 2. a continuous undeformed sub-horizontal ~1.5 to 10 km thick wedge of the Cape Supergroup (CSG). This CSG wedge stretches from the Escarpment in the north to the tectonic front of the CFB in the south, and rests on an unconformity that dips about three degrees to the south. The angular unconformity is interpreted as an erosional peneplain that separates the CSG wedge from component 3. the ~13 to 21 km mid-crust basement below. The mid-crust contains a distinct north-dipping seismic fabric, here interpreted as ~1.4 to 1.0 Ga Mesoproterozoic Namaqua-Natal Metamorphic Belt (NNMB) crust. A south-dipping mid-crustal detachment, interpreted as a ductile thrust zone, separates the mid-crust from component 4. a highly reflective ~10 to 24 km thick lower crust. The latter is interpreted as an older Palaeoproterozoic section of the NNMB (or even Archean cratonic basement), and bounded by a ~2 to 5 km thick, highly reflective bottom layer below that lies sub-parallel to a clear Moho. This bottom layer is interpreted as a mafic underplate, metasomatic reaction zone, or lower-crust to mantle transition zone. Collectively the seismic reflection and wide-angle refraction data support an interpretation that the NNMB mid-crustal layer contains the BMA source, possibly connected to two zones of strong reflectivity: a ~10 to 12 km wide northern zone and a ~5 to 7 km wide southern zone, both about 5 km thick and 7 to 8 km below surface. We interpret the BMA source to be at least in part, a Namaqua-like massive to disseminated, deformed/metamorphosed stratiform sulphide-magnetite ore body with metasomatic overprint.The seismic reflection and -refraction data support an interpretation that a Pan-African suture zone at the BMA is absent and that instead, the NNMB continues below the CFB tectonic front, probably up to the continental margin and the Agulhas Fracture Zone. The seismic reflection data also supports a thin-skinned tectonic thrust model for the evolution of the CFB without significant fore-deep stratigraphic thickening of the Karoo Basin strata. A compatible tectonic model implies a Palaeozoic collision orogen setting, coupled to a south verging subduction zone much farther south of the CFB. Similarly, the geophysical data support a south dipping subduction zone during the amalgamation of the NNMB in the Mesoproterozoic.Current reconstructions of the Rodinia supercontinent link the NNMB and the Grenville Province of North America across the Grenville-Kibaran orogen. Our seismic section tests this reconstruction through a direct comparison with seismic profiles on the opposite flank of the orogen. Although the once adjacent continental blocks are now 1000s of kilometres apart, the seismic images show a good correlation and support the reconstruction.

Description: Substantial variations are reported for egg production and hatching rates of copepods exposed to elevated carbon dioxide concentrations (pCO 2 ). One possible explanation, as found in other marine taxa, is that prior parental exposure to elevated pCO 2 (and/or decreased pH) affects reproductive performance. Previous studies have adopted two distinct approaches, either (1) expose male and female copepoda to the test pCO 2 /pH scenarios, or (2) solely expose egg-laying females to the tests. Although the former approach is more realistic, the majority of studies have used the latter approach. Here, we investigated the variation in egg production and hatching success of Acartia tonsa between these two experimental designs, across five different pCO 2 concentrations (385–6000 µatm pCO 2 ). In addition, to determine the effect of pCO 2 on the hatching success with no prior parental exposure, eggs produced and fertilized under ambient conditions were also exposed to these pCO 2 scenarios. Significant variations were found between experimental designs, with approach (1) resulting in higher impacts; here 〉20% difference was seen in hatching success between experiments at 1000 µatm pCO 2 scenarios (2100 year scenario), and 〉85% at 6000 µatm pCO 2 . This study highlights the potential to misrepresent the reproductive response of a species to elevated pCO 2 dependent on parental exposure.

Description: ABSTRACT Introduction Hormonal fluctuations may influence fibrin structure. During the menstrual cycle, plasma fibrinogen levels change, mainly due to the variations of estrogen. Throughout the menstrual cycle estrogen levels peak twice, first during the mid-follicular phase and then a lower second peak during the luteal phase. Materials and methods In order to investigate the possible changes in the fibrin network throughout the menstrual cycle, the fibrin network ultrastructure of six healthy female participants were studied at different intervals in the menstrual cycle where differences in estrogen levels are prevalent. Blood plasma smears were prepared for scanning and transmission electron microscopy analysis. Results The external and internal structure of the fibrin fibers showed different morphologies throughout the menstrual cycle. The fibrin fibers were smooth during days 1–5. However, during days 12–14 of the menstrual cycle the fibrin fiber morphology started to change, becoming less smooth. During the luteal phase of the cycle (days 20–25), the network appears sticky, where the minor, thin fibers are more prominent between the thick fibers when compared to the menstrual phase. Conclusion The two estrogen peaks of the menstrual cycle coincide with the changes seen in the current qualitative research, where the fibrin morphology changes during the same time as the estrogen peaks occur. Purified fibrinogen confirmed that it is indeed estrogen that causes the altered fibrin network morphology. This research is the first to show ultrastructural changes in fibrin fiber morphology resulting from estrogen changes during the menstrual cycle. Microsc. Res. Tech., 2014 . © 2014 Wiley Periodicals, Inc.

Description: Environmental Science & Technology DOI: 10.1021/es400663f

Description: ABSTRACT Introduction: Normal pregnancy is characterized by significant alterations in the haemostatic system accompanied by an augmented risk of thrombosis. Materials and methods: The fibrin network ultrastructure of different phases of pregnancy, namely early pregnancy (week 8–14), late pregnancy (week 36–40) as well as post-partum (week 6–8 after birth) were compared with nonpregnant fibrin networks as well as each other to establish whether differences in fibrin network morphology exist during pregnancy. Scanning electron microscopy was employed to analyse fibrin network morphology. Results: The fibrin networks from all phases of pregnancy appeared similar to each other, exhibiting prominent coagulant formation, an increase in the formation of minor, thin fibers, and the presence of granular globules. All three phases, however, differ from the typical fibrin network ultrastructure exhibited by the fibrin networks from nonpregnant individuals. The increase in estrogen associated with pregnancy may cause the increase in coagulation factors and ultimately the prothrombotic state characteristic of pregnancy. Conclusions: Since no differences were apparent between the different phases of pregnancy it suggests that activation of the coagulation system commences with pregnancy and this pro-thrombotic state continues till at least 8 weeks after birth. These results may shed light on possible pathological mechanisms employed in the development of abnormal or ailing pregnancy. Microsc. Res. Tech., 2014 . © 2014 Wiley Periodicals, Inc.