Ocean acidification: summary for policymakers

This paper presents a summary of the state of knowledge on ocean acidification.Summary of outcomes:The ocean continues to acidify at an unprecedented rate in Earth’s history. Latest research indicates the rate of change may be faster than at any time in the last 300 million years.As ocean acidity increases, its capacity to absorb CO2 from the atmosphere decreases. This decreases the ocean’s role in moderating climate change. Species-specific impacts of ocean acidification have been seen in laboratory and field studies on organisms from the poles to the tropics. Many organisms show adverse effects, such as reduced ability to form and maintain shells and skeletons, as well as reduced survival, growth, abundance and larval development. Conversely, evidence indicates that some organisms tolerate ocean acidification and that others, such as some seagrasses, may even thrive. Within decades, large parts of the polar oceans will become corrosive to the unprotected shells of calcareous marine organisms. Changes in carbonate chemistry of the tropical ocean may hamper or prevent coral reef growth within decades.The far-reaching effects of ocean acidification are predicted to impact food webs, biodiversity, aquaculture and hence societies. Species differ in their potential to adapt to new environments. Ocean chemistry may be changing too rapidly for many species or populations to adapt through evolution.Multiple stressors – ocean acidification, warming, decreases in oceanic oxygen concentrations (deoxygenation), increasing UV-B irradiance due to stratospheric ozone depletion, overfishing, pollution and eutrophication – and their interactions are creating significant challenges for ocean ecosystems. We do not fully understand the biogeochemical feedbacks to the climate system that may arise from ocean acidification. Predicting how whole ecosystems will change in response to rising CO2 levels remains challenging. While we know enough to expect changes in marine ecosystems and biodiversity within our lifetimes, we are unable to make reliable, quantitative predictions of socio-economic impacts. People who rely on the ocean’s ecosystem services are especially vulnerable and may need to adapt or cope with ocean acidification impacts within decades. Shellfish fisheries and aquaculture in some areas may be able to cope by adjusting their management practices to avoid ocean acidification impacts. Tropical coral reef loss will affect tourism, food security and Katharina Fabricius shoreline protection for many of the world’s poorest people.Authors: Wendy Broadgate, IGBP; Ulf Riebesell, GEOMAR Helmholtz Centre for Ocean Research Kiel, Germany; Claire Armstrong, University of Tromsø, Norway; Peter Brewer, Monterey Bay Aquarium Research Institute, USA; Ken Denman, University of Victoria, Canada; Richard Feely, Pacific Marine Environmental Laboratory, NOAA, USA; Kunshan Gao, Xiamen University, China; Jean-Pierre Gattuso, CNRS-UPMC, Laboratoire d’Océanographie, France; Kirsten Isensee, IOC-UNESCO; Joan Kleypas, National Center for Atmospheric Research (Climate and Global Dynamics), USA; Dan Laffoley, International Union for Conservation of Nature, Switzerland; James Orr, Laboratoire des Sciences du Climat et l’Environnement, France; Hans-Otto Pörtner, Alfred Wegener Institute, Germany; Carlos Eduardo de Rezende, Universidade Estadual do Norte Fluminese, Brazil; Daniela Schmidt, University of Bristol, UK; Ed Urban, SCOR; Anya Waite, University of Western Australia; Luis Valdés, IOC-UNESCO

Using fractals and power laws to predict the location of mineral deposits

Around the world the mineral exploration industry is interested in getting that small increase in probability measure on the earth's surface of where the next large undiscovered deposit might be found. In particular WMC Resources Ltd has operations world wide looking for just that edge in the detection of very large deposits of, for example, gold. Since the pioneering work of Mandelbrot, geologists have been familiar with the concept of fractals and self similarity over a few orders of magnitude for geological features. This includes the location and size of deposits within a particular mineral province. Fractal dimensions have been computed for such provinces and similarities of these aggregated measures between provinces have been noted. This paper explores the possibility of making use of known information to attempt the inverse process. That is, from lesser dimensional measures of a mineral province, for example, fractal dimension or more generally multi-fractal measures, is it possible to infer, even with small increase in probability, where the unknown (preferably large) deposits might be located

Quantifying global marine isoprene fluxes using MODIS chlorophyll observations

We report global distributions of marine isoprene flux, whose source is estimated by combining an empirical relationship for isoprene production rate with MODIS satellite chlorophyll observations from 2001. We use a steady-state water column model including losses to chemistry, bacteria, and air-sea exchange. Physical mixing is a negligible sink. Flux estimates range from 107–109 molecules cm−2s−1, with considerable spatial and temporal variability, resulting in a global annual total of 0.1 Tg C/yr. Air-sea exchange is the dominant isoprene sink in the surface oceans, with bacteria the second largest, but much less important, sink. The reported fluxes represent a small loss of OH in the remote marine boundary layer (MBL) compared to other oxidants. Application of our approach to other reactive compounds may improve a priori flux estimates for coupled atmosphere-ocean biogeochemistry inverse model studies

Spatial and temporal variability of biogenic isoprene emissions from a temperate estuary

[1] Isoprene is important for its atmospheric impacts and the ecophysiological benefits it affords to emitting organisms; however, isoprene emissions from marine systems remain vastly understudied compared to terrestrial systems. This study investigates for the first time drivers of isoprene production in a temperate estuary, and the role this production may play in enabling organisms to tolerate the inherently wide range of environmental conditions. Intertidal sediment cores as well as high and low tide water samples were collected from four sites along the Colne Estuary, UK, every six weeks over a year. Isoprene concentrations in the water were significantly higher at low than high tide, and decreased toward the mouth of the estuary; sediment production showed no spatial variability. Diel isoprene concentration increased with light availability and decreased with tidal height; nighttime production was 79% lower than daytime production. Seasonal isoprene production and water concentrations were highest for the warmest months, with production strongly correlated with light (r2 = 0.800) and temperature (r2 = 0.752). Intertidal microphytobenthic communities were found to be the primary source of isoprene, with tidal action acting as a concentrating factor for isoprene entering the water column. Using these data we estimated an annual production rate for this estuary of 681 μmol m−2 y−1. This value falls at the upper end of other marine estimates and highlights the potentially significant role of estuaries as isoprene sources. The control of estuarine isoprene production by environmental processes identified here further suggests that such emissions may be altered by future environmental change

The trajectory of the Anthropocene: The Great Acceleration

The ‘Great Acceleration’ graphs, originally published in 2004 to show socio-economic and Earth System trends from 1750 to 2000, have now been updated to 2010. In the graphs of socio-economic trends, where the data permit, the activity of the wealthy (OECD) countries, those countries with emerging economies, and the rest of the world have now been differentiated. The dominant feature of the socio-economic trends is that the economic activity of the human enterprise continues to grow at a rapid rate. However, the differentiated graphs clearly show that strong equity issues are masked by considering global aggregates only. Most of the population growth since 1950 has been in the non-OECD world but the world’s economy (GDP), and hence consumption, is still strongly dominated by the OECD world. The Earth System indicators, in general, continued their long-term, post-industrial rise, although a few, such as atmospheric methane concentration and stratospheric ozone loss, showed a slowing or apparent stabilisation over the past decade. The post-1950 acceleration in the Earth System indicators remains clear. Only beyond the mid-20th century is there clear evidence for fundamental shifts in the state and functioning of the Earth System that are beyond the range of variability of the Holocene and driven by human activities. Thus, of all the candidates for a start date for the Anthropocene, the beginning of the Great Acceleration is by far the most convincing from an Earth System science perspective.</jats:p

Detailed phenotypic and genotypic characterization of bietti crystalline dystrophy

OBJECTIVE: To provide a detailed phenotype/genotype characterization of Bietti crystalline dystrophy (BCD). DESIGN: Observational case series. PARTICIPANTS: Twenty patients from 17 families recruited from a multiethnic British population. METHODS: Patients underwent color fundus photography, near-infrared (NIR) imaging, fundus autofluorescence (FAF) imaging, spectral domain optical coherence tomography (SD-OCT), and electroretinogram (ERG) assessment. The gene CYP4V2 was sequenced. MAIN OUTCOME MEASURES: Clinical, imaging, electrophysiologic, and molecular genetics findings. RESULTS: Patients ranged in age from 19 to 72 years (median, 40 years), with a visual acuity of 6/5 to perception of light (median, 6/12). There was wide intrafamilial and interfamilial variability in clinical severity. The FAF imaging showed well-defined areas of retinal pigment epithelium (RPE) loss that corresponded on SD-OCT to well-demarcated areas of outer retinal atrophy. Retinal crystals were not evident on FAF imaging and were best visualized with NIR imaging. Spectral domain OCT showed them to be principally located on or in the RPE/Bruch's membrane complex. Disappearance of the crystals, revealed by serial recording, was associated with severe disruption and thinning of the RPE/Bruch's membrane complex. Cases with extensive RPE degeneration (N = 5) had ERGs consistent with generalized rod and cone dysfunction, but those with more focal RPE atrophy showed amplitude reduction without delay (N = 3), consistent with restricted loss of function, or that was normal (N = 2). Likely disease-causing variants were identified in 34 chromosomes from 17 families. Seven were novel, including p.Met66Arg, found in all 11 patients from 8 families of South Asian descent. This mutation appears to be associated with earlier onset (median age, 30 years) compared with other substitutions (median age, 41 years). Deletions of exon 7 were associated with more severe disease. CONCLUSIONS: The phenotype is highly variable. Several novel variants are reported, including a highly prevalent substitution in patients of South Asian descent that is associated with earlier-onset disease. Autofluorescence showed sharply demarcated areas of RPE loss that coincided with abrupt edges of outer retinal atrophy on SD-OCT; crystals were generally situated on or in the RPE/Bruch's complex but could disappear over time with associated RPE disruption. These results support a role for the RPE in disease pathogenesis

Identification and characterisation of isoprene-degrading bacteria in an estuarine environment

Approximately one-third of volatile organic compounds (VOCs) emitted to the atmosphere consists of isoprene, originating from the terrestrial and marine biosphere, with a profound effect on atmospheric chemistry. However, isoprene provides an abundant and largely unexplored source of carbon and energy for microbes. The potential for isoprene degradation in marine and estuarine samples from the Colne Estuary, UK, was investigated using DNA-Stable Isotope Probing (DNA-SIP). Analysis at two timepoints showed the development of communities dominated by Actinobacteria including members of the genera Mycobacterium, Rhodococcus, Microbacterium and Gordonia. Representative isolates, capable of growth on isoprene as sole carbon and energy source, were obtained from marine and estuarine locations, and isoprene-degrading strains of Gordonia and Mycobacterium were characterised physiologically and their genomes were sequenced. Genes predicted to be required for isoprene metabolism, including four-component isoprene monooxygenases (IsoMO), were identified and compared with previously characterised examples. Transcriptional and activity assays of strains growing on isoprene or alternative carbon sources showed that growth on isoprene is an inducible trait requiring a specific IsoMO. This study is the first to identify active isoprene degraders in estuarine and marine environments using DNA-SIP and to characterise marine isoprene-degrading bacteria at the physiological and molecular level

Isolation of isoprene degrading bacteria from soils, development of isoA gene probes and identification of the active isoprene degrading soil community using DNA-stable isotope probing

Emissions of biogenic volatile organic compounds (bVOCs), are an important element in the global carbon cycle, accounting for a significant proportion of fixed carbon. They contribute directly and indirectly to global warming and climate change and have a major effect on atmospheric chemistry. Plants emit isoprene to the atmosphere in similar quantities to emissions of methane from all sources and each account for approximately one third of total VOCs. Although methanotrophs, capable of growth on methane, have been intensively studied, we know little of isoprene biodegradation. Here we report the isolation of two isoprene-degrading strains from the terrestrial environment and describe the design and testing of PCR primers targeting isoA, the gene encoding the active-site component of the conserved isoprene monooxygenase, which are capable of retrieving isoA sequences from isoprene-enriched environmental samples. Stable isotope probing experiments, using biosynthesized 13C-labelled isoprene, identified the active isoprene-degrading bacteria in soil. This study identifies novel isoprene-degrading strains using both culture-dependent and, for the first time, culture-independent methods and provides the tools and foundations for continued investigation of the biogeography and molecular ecology of isoprene-degrading bacteria. This article is protected by copyright. All rights reserved

Characterization of CDH3-Related Congenital Hypotrichosis With Juvenile Macular Dystrophy.

IMPORTANCE: Congenital hypotrichosis with juvenile macular dystrophy (HJMD) is a rare disorder presenting in childhood and adolescence with central visual disturbance and sparse scalp hair. Reported retinal imaging is lacking, and whether the condition is progressive remains unclear. OBJECTIVE: To investigate a series of patients with HJMD due to biallelic mutations in CDH3 and thereby characterize the disorder. DESIGN, SETTING, AND PARTICIPANTS: Ten patients from 10 families underwent detailed clinical assessment, including serial retinal imaging and electrophysiologic evaluation, at Moorfields Eye Hospital, St James's University Hospital, and Calderdale Royal Infirmary. Patients ranged in age from 3 to 17 years at onset and 5 to 57 years at last assessment. The molecular genetic investigation included bidirectional Sanger sequencing of all exons and intron-exon boundaries of CDH3 and whole-exome sequencing in 2 patients. The study was conducted from June 5, 2013, to January 15, 2016, with final follow-up completed on December 15, 2015. MAIN OUTCOMES AND MEASURES: Results of clinical assessment and molecular genetic testing. RESULTS: All 10 patients (7 male and 3 female) presented with central visual disturbance in childhood and had lifelong sparse scalp hair with normal facial hair. Fundus examination revealed chorioretinal atrophy of the posterior pole contiguous with the disc in all but 1 patient that was associated with marked loss of autofluorescence on fundus autofluorescence imaging. Optical coherence tomography (OCT) demonstrated variable degrees of atrophy of the outer retina, retinal pigment epithelium, and choroid, with outer retinal tubulations frequently observed. One patient had mild disruption of the inner segment ellipsoid band on OCT and additional mild digit abnormalities. Electrophysiologic evaluation in 5 patients demonstrated macular dysfunction with additional mild, generalized retinal dysfunction in 2 patients. Eight patients had more than 1 evaluation; of these, 5 patients showed deterioration of visual acuity over time, 1 patient remained stable, and 2 patients had severe visual loss at presentation that precluded assessment of visual deterioration. The area of atrophy did not progress with time, but retinal thickness decreased on OCT. Electrophysiologic evaluation in 1 patient found deterioration of macular function after 13 years of follow-up, but the mild, generalized photoreceptor dysfunction remained stable. Biallelic mutations were identified in all patients, including 6 novel mutations. CONCLUSIONS AND RELEVANCE: These results suggest that CDH3-related disease is characterized by a childhood-onset, progressive chorioretinal atrophy confined to the posterior pole. The disease is readily distinguished from other juvenile macular dystrophies by the universally thin and sparse scalp hair. Patients may have additional limb abnormalities