| 1. |
- Abila, R., et al.
(author)
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Oil extraction imperils Africa’s Great Lakes
- 2016
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In: Science. - : American Association for the Advancement of Science (AAAS). - 0036-8075 .- 1095-9203. ; 354:6312, s. 561-562
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Journal article (other academic/artistic)abstract
- As the world's demands for hydrocarbons increase (1), remote areas previously made inaccessible by technological limitations are now being prospected for oil and gas deposits. Virtually unnoticed by the public, such activities are ongoing in the East African Great Lakes region, threatening these ecosystems famed for their hyper-diverse biota, including the unique adaptive radiations of cichlid fishes (2). Countries in the region see exploitation of hydrocarbon reserves as a vital economic opportunity. In the Lake Albert region of Uganda, for example, the government foresees a $3.6 billion oil profit per year starting in 2018—a sum almost as high as the country's current annual budget (3). However, oil extraction in the East African Great Lakes region poses grave risks to the environment and local communities.
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| 2. |
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| 3. |
- Feng, Xue, et al.
(author)
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Beyond isohydricity : The role of environmental variability in determining plant drought responses
- 2019
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In: Plant, Cell and Environment. - : Wiley. - 0140-7791 .- 1365-3040. ; 42:4, s. 1104-1111
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Journal article (peer-reviewed)abstract
- Despite the appeal of the iso/anisohydric framework for classifying plant drought responses, recent studies have shown that such classifications can be strongly affected by a plant's environment. Here, we present measured in situ drought responses to demonstrate that apparent isohydricity can be conflated with environmental conditions that vary over space and time. In particular, we (a) use data from an oak species (Quercus douglasii) during the 2012-2015 extreme drought in California to demonstrate how temporal and spatial variability in the environment can influence plant water potential dynamics, masking the role of traits; (b) explain how these environmental variations might arise from climatic, topographic, and edaphic variability; (c) illustrate, through a common garden thought experiment, how existing trait-based or response-based isohydricity metrics can be confounded by these environmental variations, leading to Type-1 (false positive) and Type-2 (false negative) errors; and (d) advocate for the use of model-based approaches for formulating alternate classification schemes. Building on recent insights from greenhouse and vineyard studies, we offer additional evidence across multiple field sites to demonstrate the importance of spatial and temporal drivers of plants' apparent isohydricity. This evidence challenges the use of isohydricity indices, per se, to characterize plant water relations at the global scale.
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| 4. |
- Fairchild, Ian J., et al.
(author)
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Tonian-Cryogenian boundary sections of Argyll, Scotland
- 2018
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In: Precambrian Research. - : Elsevier BV. - 0301-9268 .- 1872-7433. ; 319, s. 37-64
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Journal article (peer-reviewed)abstract
- The Tonian-Cryogenian System boundary is to be defined at a GSSP (Global Boundary Stratigraphic Section and Point) beneath the first evidence of widespread glaciation. A candidate lies within the Dalradian Supergroup of Scotland and Ireland, which is least deformed and metamorphosed in Argyll, western Scotland. We present new stratigraphic profiles and interpretations from the Isle of Islay and the Garvellach Islands, update the chemostratigraphy of the Appin Group Tonian carbonates underlying the thick (ca. 1 km) glacigenic Port Askaig Formation (PAF) and demonstrate an environmental transition at the contact. The Appin Group forms a regionally extensive, > 4 km-thick, succession of limestones, shales and sandstones deposited on a marine shelf. On Islay, the upper part of the lithostratigraphy has been clarified by measuring and correlating two sections containing distinctive stratigraphic levels including molar tooth structure, oolite, stromatolitic dolomite and intraclastic microbial mounds. Significantly deeper erosion at the unconformity at the base of the overlying PAF is demonstrated in the southern section. Carbonate facies show a gradual decline in delta C-13(VPDB) from +5 to + 2 parts per thousand upwards. In NE Garbh Eileach (Garvellach Islands), a continuously exposed section of Appin Group carbonates, 70 m thick, here designated the Garbh Eileach Formation (GEF), lies conformably beneath the PAF. The GEF and the GEF-PAF boundary relationships are re -described with new sedimentological logs, petrological and stable isotope data. Interstratified limestone and dolomicrosparite with delta C-13 of -4 to -7 parts per thousand (a feature named the Garvellach anomaly, replacing the term Islay anomaly) are overlain by dolomite in which the isotope signature becomes weakly positive (up to +1 parts per thousand) upwards. Shallow subtidal conditions become peritidal upwards, with evidence of wave and storm activity. Gypsum pseudomorphs and subaerial exposure surfaces are common near the top of the GEF. The basal diamictite (D1) of the PAF is rich in carbonate clasts similar to slightly deeper water parts of the underlying succession. D1 is typically several metres thick with interstratified sandstone and conglomerate, but dies out laterally. Scattered siliciclastic coarse sandstone to pebble conglomerate with dropstones associated with soft -sediment deformation is interbedded with carbonate below and above D1. Dolomite beds with derived intraclasts and gypsum pseudomorphs are found above D1 (or equivalent position, where Dl is absent). Published and new Sr isotope studies, including successive leach data, demonstrate primary Tonian Sr-87/Sr-86 values of 0.7066-0.7069 on Islay, decreasing to 0.7064-0.7066 in the younger GEF limestones on the Garvellachs, with 1700-2700 ppm Sr. Other typically Tonian characteristics of the carbonates are the Sr-rich nature of limestones, molar tooth structure, and dolomitized peritidal facies with evidence of aridity. Seabed surveys suggesting uniformly-dipping strata and shallow borehole core material illustrate the potential for extending the Tonian record offshore of the Garvellachs. A candidate Tonian-Cryogenian GSSP is proposed on Garbh Eileach within the smooth delta C-13 profile at the cross-over to positive delta C-13 signatures, 4 m below the first occurrence of ice-rafted sediment and 9 m below the first diamictite. Although lacking radiometric constraints or stratigraphically significant biotas or biomarkers, the Scottish succession has a thick and relatively complete sedimentary record of glaciation, coherent carbon and strontium chemostratigraphy, lateral continuity of outcrops and 100% exposure at the proposed boundary interval.
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| 5. |
- Feng, Xue, et al.
(author)
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The ecohydrological context of drought and classification of plant responses
- 2018
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In: Ecology Letters. - : Wiley. - 1461-023X .- 1461-0248. ; 21:11, s. 1723-1736
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Research review (peer-reviewed)abstract
- Many recent studies on drought‐induced vegetation mortality have explored how plant functional traits, and classifications of such traits along axes of, for example, isohydry–anisohydry, might contribute to predicting drought survival and recovery. As these studies proliferate, the consistency and predictive value of such classifications need to be carefully examined. Here, we outline the basis for a systematic classification of plant drought responses that accounts for both environmental conditions and functional traits. We use non‐dimensional analysis to integrate plant traits and metrics of environmental variation into groups that can be associated with alternative drought stress pathways (hydraulic failure and carbon limitation), and demonstrate that these groupings predict physiological drought outcomes using both synthetic and measured data. In doing so, we aim to untangle some confounding effects of environment and trait variations that undermine current classification schemes, advocate for more careful treatment of the environmental context within which plants experience and respond to drought, and outline a pathway towards a general classification of drought vulnerability.
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| 6. |
- Landler, Lukas, et al.
(author)
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Ectosymbionts alter spontaneous responses to the Earth’s magnetic field in a crustacean
- 2019
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In: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 9:1
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Journal article (peer-reviewed)abstract
- Magnetic sensing is used to structure every-day, non-migratory behaviours in many animals. We show that crayfish exhibit robust spontaneous magnetic alignment responses. These magnetic behaviours are altered by interactions with Branchiobdellidan worms, which are obligate ectosymbionts. Branchiobdellidan worms have previously been shown to have positive effects on host growth when present at moderate densities, and negative effects at relatively high densities. Here we show that crayfish with moderate densities of symbionts aligned bimodally along the magnetic northeast-southwest axis, similar to passive magnetic alignment responses observed across a range of stationary vertebrates. In contrast, crayfish with high symbiont densities failed to exhibit consistent alignment relative to the magnetic field. Crayfish without symbionts shifted exhibited quadramodal magnetic alignment and were more active. These behavioural changes suggest a change in the organization of spatial behaviour with increasing ectosymbiont densities. We propose that the increased activity and a switch to quadramodal magnetic alignment may be associated with the use of systematic search strategies. Such a strategy could increase contact-rates with conspecifics in order to replenish the beneficial ectosymbionts that only disperse between hosts during direct contact. Our results demonstrate that crayfish perceive and respond to magnetic fields, and that symbionts influence magnetically structured spatial behaviour of their hosts.
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