Diamonds and their mineral inclusions from the A154 South pipe, Diavik Diamond Mine, Northwest territories, Canada

Mineral inclusions recovered from 100 diamonds from the A154 South kimberlite (Diavik Diamond Mines, Central Slave Craton, Canada) indicate largely peridotitic diamond sources (83%), with a minor (12%) eclogitic component. Inclusions of ferropericlase (4%) and diamond in diamond (1%) represent “undetermined” parageneses.

Compared to inclusions in diamonds from the Kaapvaal Craton, overall higher CaO contents (2.6 to 6.0 wt.%) of harzburgitic garnets and lower Mg-numbers (90.6 to 93.6) of olivines indicate diamond formation in a chemically less depleted environment. Peridotitic diamonds at A154 South formed in an exceptionally Zn-rich environment, with olivine inclusions containing more than twice the value (of  52 ppm) established for normal mantle olivine. Harzburgitic garnet inclusions generally have sinusoidal rare earth element (REE_N) patterns, enriched in LREE and depleted in HREE. A single analyzed lherzolitic garnet is re-enriched in middle to heavy REE resulting in a “normal” REE_N pattern. Two of the harzburgitic garnets have “transitional” REE_N patterns, broadly similar to that of the lherzolitic garnet. Eclogitic garnet inclusions have normal REE_N patterns similar to eclogitic garnets worldwide but at lower REE concentrations.

Carbon isotopic values (δ¹³C) range from − 10.5‰ to + 0.7‰, with 94% of diamonds falling between − 6.3‰ and − 4.0‰. Nitrogen concentrations range from below detection (< 10 ppm) to 3800 ppm and aggregation states cover the entire spectrum from poorly aggregated (Type IaA) to fully aggregated (Type IaB). Diamonds without evidence of previous plastic deformation (which may have accelerated nitrogen aggregation) typically have < 25% of their nitrogen in the fully aggregated B-centres. Assuming diamond formation beneath the Central Slave to have occurred in the Archean [Westerlund, K.J., Shirey, S.B., Richardson, S.H., Gurney, J.J., Harris, J.W., 2003b. Re–Os systematics of diamond inclusion sulfides from the Panda kimberlite, Slave craton. VIIIth International Kimberlite Conference, Victoria, Canada, Extended Abstracts, 5p.], such low aggregation states indicate mantle residence at fairly low temperatures (< 1100 °C). Geothermometry based on non-touching inclusion pairs, however, indicates diamond formation at temperatures around 1200 °C. To reconcile inclusion and nitrogen based temperature estimates, cooling by about 100–200 °C shortly after diamond formation is required.     

Larval development of Boccardia knoxi,a shell‐infesting spionid polychaete

Larvae of Boccardia knoxi (Rainer) were reared in the laboratory after dissection from brood capsules extracted from the outer shell and perio‐stracum of Cookia sulcata and Haliotis iris collected from Tasman Bay, New Zealand. All the eggs within each brood capsule developed into embryos. The dissected larvae had provisional setae and fed on phytoplankton. Larval development is described through to metamorphosis.     

Net economic effects of achieving maximum economic yield in fisheries

Improving the economic performance of fisheries is becoming increasingly important in fisheries management, and in some cases, maximum economic yield (MEY) is set as a key management target. However, recent critics of MEY as a management target have argued that a decline in the level of fishing activity necessary to achieve the target will result in a subsequent loss of economic activity elsewhere in the economy and, potentially, a net loss to society. In this paper, an input–output framework is used to estimate the net economic effects of achieving MEY in several Australian fisheries for which there is information on their short- and long-term performances when moving towards MEY. While overall losses were found in the short term, achieving MEY was found to result in a net economic benefit to society in the longer term. Local coastal communities in particular were found to benefit, although some losses were incurred elsewhere in the economy.     

Ocean acidification and photic‐zone anoxia at the Toarcian Oceanic Anoxic Event: Insights from the Adriatic Carbonate Platform

Severe global climate change led to the deterioration of environmental conditions in the oceans during the Toarcian Stage of the Jurassic. Carbonate platforms of the Western Tethys Ocean exposed in Alpine Tethyan mountain ranges today offer insight into this period of environmental upheaval. In addition to informing understanding of climate change in deep time, the effect of ancient carbon cycle perturbations on carbonate platforms has important implications for anthropogenic climate change; the patterns of early Toarcian environmental deterioration are similar to those occurring in modern oceans. This study focuses on the record of the early Toarcian Oceanic Anoxic Event (ca 183.1 Ma) in outcrops of the north‐west Adriatic Carbonate Platform in Slovenia. Amidst environmental deterioration, the north‐west Adriatic Platform abruptly transitioned from a healthy, shallow‐water environment with diverse metazoan ecosystems to a partially drowned setting with low diversity biota and diminished sedimentation. An organic carbon‐isotope excursion of ?2.2‰ reflects the massive injection of CO₂ into the ocean‐atmosphere system and marks the stratigraphic position of the Toarcian Oceanic Anoxic Event. A prominent dissolution horizon and suppressed carbonate deposition on the platform are interpreted to reflect transient shoaling of the carbonate compensation depth to unprecedentedly shallow levels as the dramatic influx of CO₂ overwhelmed the ocean’s buffering capacity, causing ocean acidification. Trace metal geochemistry and palaeoecology highlight water column deoxygenation, including the development of photic‐zone anoxia, preceding and during the Toarcian Oceanic Anoxic Event. Ocean acidification and reduced oxygen levels likely had a profoundly negative effect on carbonate‐producing biota and growth of the Adriatic Platform. These effects are consistent with the approximate doubling of the concentration of CO₂ in the ocean‐atmosphere system from pre‐event levels, which has previously been linked to a volcanic triggering mechanism. Mercury enrichments discovered in this study support a temporal and genetic link between volcanism, the Toarcian Oceanic Anoxic Event and the carbonate crisis.     

Estimates of carbon stored in harvested wood products from the United States forest service northern region, 1906-2010

Background  

Global forests capture and store significant amounts of CO₂ through photosynthesis. When carbon is removed from forests through harvest, a portion of the harvested carbon is stored in wood products, often for many decades. The United States Forest Service (USFS) and other agencies are interested in accurately accounting for carbon flux associated with harvested wood products (HWP) to meet greenhouse gas monitoring commitments and climate change adaptation and mitigation objectives. This paper uses the Intergovernmental Panel on Climate Change (IPCC) production accounting approach and the California Forest Project Protocol (CFPP) to estimate HWP carbon storage from 1906 to 2010 for the USFS Northern Region, which includes forests in northern Idaho, Montana, South Dakota, and eastern Washington.     

Soil CO2 flux trends with differences in soil moisture among four types of land use in an Ecuadorian páramo landscape

Abstract

Páramo grasslands are important carbon sinks in the Ecuadorian Andes. Although carbon content of páramo Andisols is correlated with high water retention, the effects of differences in soil moisture under different types of land use on soil carbon processes have not been explicitly tested in the Ecuadorian Andes. This study assessed the relationship between soil moisture and soil CO₂ flux among a mature páramo grassland, recently burned páramo grassland, native montane forest, and pine plantation in an Ecuadorian páramo landscape. Soil CO₂ flux was greater in the forest sites compared to the grassland sites. Thus, a shift from grassland to forest cover may have significant implications for soil carbon loss via CO₂ flux. Our results suggest that although soil moisture plays a significant role in differences of soil CO₂ flux rates among land-use types, more investigation into mechanisms for soil carbon loss and how they are driven by land-use change is needed. To our knowledge, these are the first soil CO₂ flux rates reported for the Ecuadorian páramo.     

Etching of fission tracks in monazite: An experimental study

This study reports a range of etching and annealing experiments to establish the optimum conditions for the etching of fission tracks in monazite. The previously reported concentrated (12 M) HCl etchant at 90°C was found to cause grain loss from epoxy mounts and high degrees of grain corrosion, as did much longer etching times at lower temperatures. Using implanted ²⁵²Cf semi‐tracks, a series of experiments were performed on internal prismatic faces of monazite‐(Ce) crystals from the Palaeozoic Harcourt Granodiorite (Victoria, Australia) using an alternative 6 M HCl etchant, also at 90°C. Step‐etch results show optimal etching at 60–90 min. Further, an isothermal annealing experiment illustrated that the degree of annealing that can be expected during etching at 90°C under laboratory time scales is negligible. The etching rate between grains is not uniform, with a correlation demonstrated between over‐etched grains and high U and Th concentrations.     

Evolution in the discs and bulges of group galaxies since z= 0.4

We present quantitative morphology measurements of a sample of optically selected group galaxies at  0.3 < z < 0.55  using the Hubble Space Telescope ( HST ) Advanced Camera for Surveys (ACS) and the gim2d surface brightness fitting software package. The group sample is derived from the Canadian Network for Observational Cosmology Field Galaxy Redshift Survey (CNOC2) and follow-up Magellan spectroscopy. We compare these measurements to a similarly selected group sample from the Millennium Galaxy Catalogue (MGC) at  0.05 < z < 0.12  . We find that, at both epochs, the group and field fractional bulge luminosity (B/T) distributions differ significantly, with the dominant difference being a deficit of disc-dominated (B/T < 0.2) galaxies in the group samples. At fixed luminosity,   z = 0.4  groups have  ∼5.5 ± 2  per cent fewer disc-dominated galaxies than the field, while by   z = 0.1  this difference has increased to  ∼19 ± 6  per cent. Despite the morphological evolution we see no evidence that the group environment is actively perturbing or otherwise affecting the entire existing disc population. At both redshifts, the discs of group galaxies have similar scaling relations and show similar median asymmetries as the discs of field galaxies. We do find evidence that the fraction of highly asymmetric, bulge-dominated galaxies is  6 ± 3  per cent higher in groups than in the field, suggesting there may be enhanced merging in group environments. We replicate our group samples at   z = 0.4  and 0 using the semi-analytic galaxy catalogues of Bower et al. This model accurately reproduces the B/T distributions of the group and field at   z = 0.1  . However, the model does not reproduce our finding that the deficit of discs in groups has increased significantly since   z = 0.4  .     

Mapping ecosystem services at the regional scale: the validity of an upscaling approach

Mapping ecosystem services (ES) over large scales is important for environmental monitoring but is often prohibitively expensive and difficult. We test a hybrid, low-cost method of mapping ES indicators over large scales in Pará State, Brazil. Four ES indicators (vegetation carbon stocks, biodiversity index, soil chemical quality index and rates of water infiltration into soil) were measured in the field and then summarized spatially for regional land-cover classes derived from satellite imagery. The regionally mapped ES values correlated strongly with independent and local measures of ES. For example, regional estimates of the vegetation carbon stocks are strongly correlated with actual measures derived from field samples and validation data (significant anova test – p-value = 4.51^e?9) and differed on average by only 20 Mg/ha from the field data. Our spatially-nested approach provides reliable and accurate maps of ES at both local and regional scales. Local maps account for the specificities of an area while regional maps provide an accurate generalization of an ES’ state. Such up-scaling methods infuse large-scale ES maps with localized data and enable the estimation of uncertainty of at regional scales. Our approach is first step towards the spatial characterization of ES at large and potentially global scales.