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Journal articleBanks-Leite C, Fletcher R, Didham R, et al., 2018,
Is habitat fragmentation good for biodiversity?
, Biological Conservation, Vol: 226, Pages: 9-15, ISSN: 0006-3207Habitat loss is a primary threat to biodiversity across the planet, yet contentious debate has ensued on the importance of habitat fragmentation ‘per se’ (i.e., altered spatial configuration of habitat for a given amount of habitat loss). Based on a review of landscape-scale investigations, Fahrig (2017; Ecological responses to habitat fragmentation per se. Annual Review of Ecology, Evolution, and Systematics 48:1-23) reports that biodiversity responses to habitat fragmentation ‘per se’ are more often positive rather than negative and concludes that the widespread belief in negative fragmentation effects is a ‘zombie idea’. We show that Fahrig's conclusions are drawn from a narrow and potentially biased subset of available evidence, which ignore much of the observational, experimental and theoretical evidence for negative effects of altered habitat configuration. We therefore argue that Fahrig's conclusions should be interpreted cautiously as they could be misconstrued by policy makers and managers, and we provide six arguments why they should not be applied in conservation decision-making. Reconciling the scientific disagreement, and informing conservation more effectively, will require research that goes beyond statistical and correlative approaches. This includes a more prudent use of data and conceptual models that appropriately partition direct vs indirect influences of habitat loss and altered spatial configuration, and more clearly discriminate the mechanisms underpinning any changes. Incorporating these issues will deliver greater mechanistic understanding and more predictive power to address the conservation issues arising from habitat loss and fragmentation.
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Journal articleRichards FD, Kalnins LM, Watts AB, et al., 2018,
The morphology of the Tasmantid seamounts: interactions between tectonic inheritance and magmatic evolution
, Geochemistry, Geophysics, Geosystems, Vol: 19, Pages: 3870-3891, ISSN: 1525-2027Basement structure is known to exert strong magmatic and morphological control on continental volcanoes, but relatively little is known about the structural control of submarine volcanoes. Here we investigate the morphology of the Tasmantid Seamounts, a >2,400 km long chain of age‐progressive intraplate volcanoes, ranging from 56 to 7 Ma. The seamounts are emplaced over the extinct Tasman Sea spreading center, which was active between 84 and 52 Ma. While thick sediment (∼1 km) obscures much of the basement, detailed morphological and geophysical analyses of the seamounts reveal a strong correlation between tectonic setting, seamount orientation, and volcanic structure, despite the ≥20 Ma interval between spreading cessation and seamount emplacement. Seamounts emplaced on fracture zones or spreading segment‐transform fault inside corners are typically large and elongate. Where original morphology is preserved, they often appear rugged and predominantly fissure‐fed. By contrast, comparatively smooth, conical seamounts with isolated dike‐fed flank cones are often found midsegment and at outside corners. Volcanic fabrics also align closely with the expected principal stress directions for strong mechanical coupling across transform faults. This behavior suggests the lithosphere is dissected by numerous deep faults, channeling magma along preexisting structural trends. Generally, low effective elastic thicknesses (<10 km) and lack of correlation with plate age at emplacement suggest that structural inheritance is also a major control on lithospheric strength near the extinct spreading center. Our study clearly demonstrates that, like in the continents, structural inheritance in oceanic lithosphere can exert significant control on the morphology of submarine volcanoes.
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Journal articlePant NC, Jimenez-Espejo FJ, Cook CP, et al., 2018,
Suspected meteorite fragments in marine sediments from East Antarctica
, ANTARCTIC SCIENCE, Vol: 30, Pages: 307-321, ISSN: 0954-1020 -
Conference paperKarhunen V, Wiklund P, Jarvelin M-R, et al., 2018,
Joint genetic factors of body mass index and ADHD components
, 27th Annual Meeting of the International-Genetic-Epidemiology-Society (IGES), Publisher: WILEY, Pages: 709-709, ISSN: 0741-0395 -
Journal articleLi YI, Toumi R, 2018,
Improved tropical cyclone intensity forecasts by assimilating coastal surface currents in an idealized study
, Geophysical Research Letters, Vol: 45, Pages: 10019-10026, ISSN: 0094-8276High‐frequency (HF) radars can provide high‐resolution and frequent ocean surface currents observations during tropical cyclone (TC) landfall. We describe the first assimilation of such potential observations using idealized twin experiments with and without these observations. The data assimilation system consists of the Ensemble Adjustment Kalman Filter and a coupled ocean‐atmosphere model. In this system, synthetic HF radar‐observed coastal currents are assimilated, and the 24‐, 48‐ and 72‐hr forecast performances are examined for TCs with various intensities, sizes, and translation speeds. Assimilating coastal surface currents improves the intensity forecast. The errors of the maximum wind speed reduce by 2.7 (33%) and 1.9 m/s (60%) in the 72‐hr forecast and 2.8 (40%) and 1.4 m/s (62%) in the 48‐hr forecast, for Category 4 and 2 cyclones, respectively. These improvements are similar to the current operational TC forecast errors, so that assimilating HF radar observations could be a substantial benefit.
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Journal articleEwers RM, 2018,
Boring speakers talk for longer
, NATURE, Vol: 561, Pages: 464-464, ISSN: 0028-0836 -
Working paperGryspeerdt E, Goren T, Sourdeval O, et al., 2018,
Constraining the aerosol influence on cloud liquid water path
, Publisher: Copernicus PublicationsThe impact of aerosols on cloud properties is one of the largest uncertainties in the anthropogenic radiative forcing of the climate. In recent years, significant progress has been made in constraining this forcing using observations, but uncertainty still remains, particularly in the adjustments of cloud properties to aerosol perturbations. Cloud liquid water path (LWP) is the leading control on liquid-cloud albedo, making it important to observationally constrain the aerosol impact LWP.Previous modelling and observational studies have shown that multiple processes play a role in determining the LWP response to aerosol perturbations, but that the aerosol effect can be difficult to isolate. Following previous studies using mediating variables, this work investigates use of the relationship between cloud droplet number concentration (Nd) and LWP for constraining the role of aerosols. Using joint probability histograms to account for the non-linear relationship, this work finds a relationship that is broadly consistent with previous studies. There is significant geographical variation in the relationship, partly due to role of meteorological factors (particularly relative humidity) in the relationship. However, the Nd-LWP relationship is negative in the majority of regions, suggesting that aerosol induced LWP reductions could offset a significant fraction of the radiative forcing from aerosol-cloud interactions (RFaci).However, variations in the Nd-LWP relationship in response to volcanic and shipping aerosol perturbations indicate that the Nd-LWP relationship overestimates the Nd impact on LWP. As such, the estimate of LWP changes due to aerosol in this work provides an upper bound to the radiative forcing from aerosol-induced changes in the LWP.
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Journal articleWatkins S, Whittaker A, Bell RE, et al., 2018,
Are landscapes buffered to high frequency climate change? A comparison of sediment fluxes and depositional volumes in the Corinth Rift, central Greece, over the past 130 kyrs
, Geological Society of America Bulletin, Vol: 131, Pages: 372-388, ISSN: 0016-7606Sediment supply is a fundamental control on the stratigraphic record. However, a key question is the extent to which climate affects sediment fluxes in time and space. To address this question, estimates of sediment fluxes can be compared with measured sediment volumes within a closed basin with well-constrained tectonic boundary conditions and well-documented climate variability. The Corinth rift, central Greece, is one of the most actively extending basins on Earth, with modern day GPS extension rates of up to 15 mm/yr. The Gulf of Corinth forms a closed system and since ~600 ka the gulf has fluctuated between being marine and a lake. We have estimated suspended sediment fluxes for rivers draining into the Gulf of Corinth using the empirically-derived BQART method over the last interglacial-glacial-interglacial cycle (0-130 kyrs). Modern temperature and precipitation datasets, LGM reconstructions and palaeo climate proxy insights were used to constrain model inputs. Simultaneously, we exploited high-resolution 2D seismic surveys to interpret three seismic units from 130 ka to present and we used this data to derive an independent time series of basin sedimentary volumes to compare with our sediment input flux estimates. Our results predict total Holocene sediment fluxes into the Gulf of Corinth of between 19.2 km3 and 23.4 km3 with a preferred estimate of 21.3 km3. This value is a factor of 1.6 less than the measured Holocene sediment volume in the central depocentres, even without taking lithological factors into account, suggesting that the BQART method provides plausible estimates. Sediment fluxes vary spatially around the Gulf, and we use them to derive minimum catchment-averaged denudation rates of 0.18 to 0.55 mm/yr. Significantly, our time series of basin sedimentary volumes demonstrate a clear reduction in sediment accumulation rates during the last glacial period compared to the current interglacial. This implies that Holocene sediment fluxes must have in
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Journal articleWilson DJ, Bertram R, Needham E, et al., 2018,
Ice loss from the East Antarctic Ice Sheet during late Pleistocene interglacials
, Nature, Vol: 561, Pages: 383-386, ISSN: 0028-0836Understanding ice sheet behaviour in the geological past is essential for evaluating the role of the cryosphere in the climate system and for projecting rates and magnitudes of sea level rise in future warming scenarios1,2,3,4. Although both geological data5,6,7 and ice sheet models3,8 indicate that marine-based sectors of the East Antarctic Ice Sheet were unstable during Pliocene warm intervals, the ice sheet dynamics during late Pleistocene interglacial intervals are highly uncertain3,9,10. Here we provide evidence from marine sedimentological and geochemical records for ice margin retreat or thinning in the vicinity of the Wilkes Subglacial Basin of East Antarctica during warm late Pleistocene interglacial intervals. The most extreme changes in sediment provenance, recording changes in the locus of glacial erosion, occurred during marine isotope stages 5, 9, and 11, when Antarctic air temperatures11 were at least two degrees Celsius warmer than pre-industrial temperatures for 2,500 years or more. Hence, our study indicates a close link between extended Antarctic warmth and ice loss from the Wilkes Subglacial Basin, providing ice-proximal data to support a contribution to sea level from a reduced East Antarctic Ice Sheet during warm interglacial intervals. While the behaviour of other regions of the East Antarctic Ice Sheet remains to be assessed, it appears that modest future warming may be sufficient to cause ice loss from the Wilkes Subglacial Basin.
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Journal articleReiner RC, Graetz N, Casey DC, et al., 2018,
Variation in Childhood Diarrheal Morbidity and Mortality in Africa, 2000-2015
, New England Journal of Medicine, Vol: 379, Pages: 1128-1138, ISSN: 0028-4793BackgroundDiarrheal diseases are the third leading cause of disease and death in children younger than 5 years of age in Africa and were responsible for an estimated 30 million cases of severe diarrhea (95% credible interval, 27 million to 33 million) and 330,000 deaths (95% credible interval, 270,000 to 380,000) in 2015. The development of targeted approaches to address this burden has been hampered by a paucity of comprehensive, fine-scale estimates of diarrhea-related disease and death among and within countries.MethodsWe produced annual estimates of the prevalence and incidence of diarrhea and diarrhea-related mortality with high geographic detail (5 km2) across Africa from 2000 through 2015. Estimates were created with the use of Bayesian geostatistical techniques and were calibrated to the results from the Global Burden of Diseases, Injuries, and Risk Factors Study 2016.ResultsThe results revealed geographic inequality with regard to diarrhea risk in Africa. Of the estimated 330,000 childhood deaths that were attributable to diarrhea in 2015, more than 50% occurred in 55 of the 782 first-level administrative subdivisions (e.g., states). In 2015, mortality rates among first-level administrative subdivisions in Nigeria differed by up to a factor of 6. The case fatality rates were highly varied at the national level across Africa, with the highest values observed in Benin, Lesotho, Mali, Nigeria, and Sierra Leone.ConclusionsOur findings showed concentrated areas of diarrheal disease and diarrhea-related death in countries that had a consistently high burden as well as in countries that had considerable national-level reductions in diarrhea burden. (Funded by the Bill and Melinda Gates Foundation.)
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