166 research outputs found

    The impact of flooding on aquatic ecosystem services

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    Flooding is a major disturbance that impacts aquatic ecosystems and the ecosystem services that they provide. Predicted increases in global flood risk due to land use change and water cycle intensification will likely only increase the frequency and severity of these impacts. Extreme flooding events can cause loss of life and significant destruction to property and infrastructure, effects that are easily recognized and frequently reported in the media. However, flooding also has many other effects on people through freshwater aquatic ecosystem services, which often go unrecognized because they are less evident and can be difficult to evaluate. Here, we identify the effects that small magnitude frequently occurring floods (\u3c 10-year recurrence interval) and extreme floods (\u3e 100-year recurrence interval) have on ten aquatic ecosystem services through a systematic literature review. We focused on ecosystem services considered by the Millennium Ecosystem Assessment including: (1) supporting services (primary production, soil formation), (2) regulating services (water regulation, water quality, disease regulation, climate regulation), (3) provisioning services (drinking water, food supply), and (4) cultural services (aesthetic value, recreation and tourism). The literature search resulted in 117 studies and each of the ten ecosystem services was represented by an average of 12 ± 4 studies. Extreme floods resulted in losses in almost every ecosystem service considered in this study. However, small floods had neutral or positive effects on half of the ecosystem services we considered. For example, small floods led to increases in primary production, water regulation, and recreation and tourism. Decision-making that preserves small floods while reducing the impacts of extreme floods can increase ecosystem service provision and minimize losses

    Mobility and bioavailability of sediment phosphorus in urban stormwater ponds

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    © 2019. American Geophysical Union. All Rights Reserved. Stormwater ponds can serve as retention hotspots for phosphorus (P) moving out of the urban environment. This retention may be reduced by P speciation that reduces the bioavailability of P to primary producers and alters its mobility in sediments. Here we examined the mobility and fate of dissolved P in urban stormwater ponds with a set of complementary field measurements and short-term laboratory and field experiments. We measured the types and amount of P in water column and sediments of urban stormwater ponds. We further assessed the mobility of different P types in pond sediments in the field and rates of P release from sediment cores maintained under laboratory conditions. Finally, we assessed P uptake rates by pond algal communities using short-term bioassay experiments. We found that dissolved organic P was highly prevalent in urban pond water and sediments and that this type of P was mobile within sediments and could be released under high or low O 2 conditions. We also found highly variable P demand by algae among stormwater ponds and that algal growth responses to P was correlated to water column N:P ratios. Altogether, our results indicate an important role for organic phosphorus cycling in urban stormwater ponds, which likely constrains the overall retention efficiency in these aquatic ecosystems

    Partial penetrance facilitates developmental evolution in bacteria

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    Development normally occurs similarly in all individuals within an isogenic population, but mutations often affect the fates of individual organisms differently. This phenomenon, known as partial penetrance, has been observed in diverse developmental systems. However, it remains unclear how the underlying genetic network specifies the set of possible alternative fates and how the relative frequencies of these fates evolve. Here we identify a stochastic cell fate determination process that operates in Bacillus subtilis sporulation mutants and show how it allows genetic control of the penetrance of multiple fates. Mutations in an intercompartmental signalling process generate a set of discrete alternative fates not observed in wild-type cells, including rare formation of two viable 'twin' spores, rather than one within a single cell. By genetically modulating chromosome replication and septation, we can systematically tune the penetrance of each mutant fate. Furthermore, signalling and replication perturbations synergize to significantly increase the penetrance of twin sporulation. These results suggest a potential pathway for developmental evolution between monosporulation and twin sporulation through states of intermediate twin penetrance. Furthermore, time-lapse microscopy of twin sporulation in wild-type Clostridium oceanicum shows a strong resemblance to twin sporulation in these B. subtilis mutants. Together the results suggest that noise can facilitate developmental evolution by enabling the initial expression of discrete morphological traits at low penetrance, and allowing their stabilization by gradual adjustment of genetic parameters

    Variation in particulate C : N : P stoichiometry across the Lake Erie watershed from tributaries to its outflow

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    © 2017 The Authors Limnology and Oceanography published by Wiley Periodicals, Inc. on behalf of Association for the Sciences of Limnology and Oceanography Human activities can cause large alterations in biogeochemical cycles of key nutrients such as carbon (C), nitrogen (N), and phosphorus (P). However, relatively little is known about how these changes alter the proportional fluxes of these elements across ecosystem boundaries from rivers to lakes. Here, we examined environmental factors influencing spatial and temporal variation in particulate C : N : P ratios across the Lake Erie watershed from its tributaries to its outflow. Throughout the study, particulate nutrient ratios ranged widely (C : N 2.0–25.8, C : P 32–530, N : P 3.7–122.9), but mean values were generally lower than previous estimates from different aquatic environments. Particulate C : N ratios varied the least across all environments, but C : P and N : P ratios increased between tributaries and coastal areas and throughout the growing season in coastal environments. These ratios also differed temporally in offshore waters as particulate C : P and N : P were higher in the spring and summer and lower in the fall and winter. Particulate C : P ratios also increased between the western/central and eastern basins indicating differential nutrient processing across the lake. These stoichiometric changes were associated with unique environmental factors among ecosystems as tributary stoichiometry was related to terrestrial land use and land cover, coastal ratios were a product of mixing between riverine and offshore waters, and offshore patterns were influenced by differences in temperature and particulate nutrient loading among basins. Overall, by studying changes in particulate C : N : P ratios across the Lake Erie watershed, our study demonstrates the power of using mass balance principles to study nutrient transformations along the aquatic continuum

    Novel downstream process and analytical tools developed for Influenza VLP vaccine

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    Vaccination remains the most effective way to prevent the infection with Influenza viruses. However, their constant antigenic drift implies that current human Influenza vaccines need to be annually updated with high inherent costs. Virus-like particles (VLPs) have become widely used as vaccine candidates because of their versatility, immunogenicity, and safety profile. In this iBET project we are attempting to produce a candidate for a universal vaccine for which 35 different VLPs (mono, trivalent and pentavalent) were purified. Here we describe three recent advances on Influenza VLPs bioprocessing: two new analytical tools and the development of an integrated all filtration purification process, inserted in the “anything but chromatography” concept. The first method is a label-free tool that uses Biolayer interferometry technology applied on an Octet platform to quantify Influenza VLPs at all stages of DSP. Human and avian sialic acid receptors were used, in order to quantify hemagglutinin (HA) content in several mono- and multivalent Influenza VLP strains. The applied method was able to detect and quantify HA from crude sample up to final VLP product with high throughput, real-time results and improved detection limits, when compared to traditional approaches, crucial for in-line monitoring of DSP. Using a click-chemistry approach that involves Azidohomoalanine incorporation and functionalization, Influenza VLPs were selectively and fluorescently tagged. Taking into account that this chemical tag does not affect particle size, charge and biological activity we report here a valuable tool to online/at-line product monitoring during DSP optimization of virus related biopharmaceuticals. Moreover, using this tool coupled with FACS we were able to discriminate between VLPs and baculovirus, the major impurity of the system. The proposed all-filtration process will be described, with special focus on the clarification stage, followed by multiple ultrafiltration and diafiltration steps to achieve the needed concentration and purity specifications. Using this all-filtration platform, we are able to speed up the time process, to improve the scale-up and to reduce costs due to the removal of chromatographic steps

    The impacts of environmental warming on Odonata: a review

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    Climate change brings with it unprecedented rates of increase in environmental temperature, which will have major consequences for the earth's flora and fauna. The Odonata represent a taxon that has many strong links to this abiotic factor due to its tropical evolutionary history and adaptations to temperate climates. Temperature is known to affect odonate physiology including life-history traits such as developmental rate, phenology and seasonal regulation as well as immune function and the production of pigment for thermoregulation. A range of behaviours are likely to be affected which will, in turn, influence other parts of the aquatic ecosystem, primarily through trophic interactions. Temperature may influence changes in geographical distributions, through a shifting of species' fundamental niches, changes in the distribution of suitable habitat and variation in the dispersal ability of species. Finally, such a rapid change in the environment results in a strong selective pressure towards adaptation to cope and the inevitable loss of some populations and, potentially, species. Where data are lacking for odonates, studies on other invertebrate groups will be considered. Finally, directions for research are suggested, particularly laboratory studies that investigate underlying causes of climate-driven macroecological patterns

    Assessing recreational fisheries in an emerging economy: Knowledge,perceptions and attitudes of catch-and-release anglers in India

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    ABSTRACT: Across the globe, catch-and-release (C&R) angling represents a leisure activity indulged by millions. The practice of C&R is commonly advocated by conservation managers because of its potential to protect local fish populations from a range of anthropogenic threats, including over-fishing. In India, C&R angling in fresh waters has a history dating back to colonial times. Despite this, little is known about the current state of the sector. To address this, an online web-based survey was conducted to target C&R anglers who fish in Indian rivers to assess their knowledge, attitudes and perceptions relating to the status of India's freshwater C&R fisheries. From a total of 148 responses, factors such as angling quality (score of 4.6/5.0); aesthetics of surroundings (4.6/5.0), presence of other wildlife (4.4/5.0), fishery management practices (4.6/5.0) and socioeconomic benefits (4.4/5.0) were evaluated. Over 65% (n = 148) of the anglers reported an observed decrease in the quality of fishing (e.g. a reduction in the size and/or numbers of fish available for capture). Respondents also considered deforestation (score of 4.2/5.0), water abstraction (4.4/5.0), pollution (4.4/5.0), hydropower projects (4.2/5.0) and destructive fishing techniques (4.7/5.0) as factors which threaten both the habitat and species they target. C&R practitioners were largely united regarding the benefits and willingness to contribute both their time and financial input to support conservation initiatives (score of 4.7/5.0). The current study provides the first overview of the status of C&R angling in India and explores challenges, opportunities, and priorities for future resource management

    Alemtuzumab CARE-MS II 5-year follow-up: Efficacy and safety findings.

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    OBJECTIVE: To evaluate 5-year efficacy and safety of alemtuzumab in patients with active relapsing-remitting multiple sclerosis and inadequate response to prior therapy. METHODS: In the 2-year Comparison of Alemtuzumab and Rebif Efficacy in Multiple Sclerosis (CARE-MS) II study (NCT00548405), alemtuzumab-treated patients received 2 courses (baseline and 12 months later). Patients could enter an extension (NCT00930553), with as-needed alemtuzumab retreatment for relapse or MRI activity. Annualized relapse rate (ARR), 6-month confirmed disability worsening (CDW; ≥1-point Expanded Disability Status Scale [EDSS] score increase [≥1.5 if baseline EDSS = 0]), 6-month confirmed disability improvement (CDI; ≥1-point EDSS decrease [baseline score ≥2.0]), no evidence of disease activity (NEDA), brain volume loss (BVL), and adverse events (AEs) were assessed. RESULTS: Most alemtuzumab-treated patients (92.9%) who completed CARE-MS II entered the extension; 59.8% received no alemtuzumab retreatment. ARR was low in each extension year (years 3-5: 0.22, 0.23, 0.18). Through 5 years, 75.1% of patients were free of 6-month CDW; 42.9% achieved 6-month CDI. In years 3, 4, and 5, proportions with NEDA were 52.9%, 54.2%, and 58.2%, respectively. Median yearly BVL remained low in the extension (years 1-5: -0.48%, -0.22%, -0.10%, -0.19%, -0.07%). AE exposure-adjusted incidence rates in the extension were lower than in the core study. Thyroid disorders peaked at year 3, declining thereafter. CONCLUSIONS: Alemtuzumab provides durable efficacy through 5 years in patients with an inadequate response to prior therapy in the absence of continuous treatment. CLASSIFICATION OF EVIDENCE: This study provides Class III evidence that alemtuzumab provides efficacy and slowing of brain atrophy through 5 years

    The Changing Face of Winter: Lessons and Questions From the Laurentian Great Lakes

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    Among its many impacts, climate warming is leading to increasing winter air temperatures, decreasing ice cover extent, and changing winter precipitation patterns over the Laurentian Great Lakes and their watershed. Understanding and predicting the consequences of these changes is impeded by a shortage of winter-period studies on most aspects of Great Lake limnology. In this review, we summarize what is known about the Great Lakes during their 3–6 months of winter and identify key open questions about the physics, chemistry, and biology of the Laurentian Great Lakes and other large, seasonally frozen lakes. Existing studies show that winter conditions have important effects on physical, biogeochemical, and biological processes, not only during winter but in subsequent seasons as well. Ice cover, the extent of which fluctuates dramatically among years and the five lakes, emerges as a key variable that controls many aspects of the functioning of the Great Lakes ecosystem. Studies on the properties and formation of Great Lakes ice, its effect on vertical and horizontal mixing, light conditions, and biota, along with winter measurements of fundamental state and rate parameters in the lakes and their watersheds are needed to close the winter knowledge gap. Overcoming the formidable logistical challenges of winter research on these large and dynamic ecosystems may require investment in new, specialized research infrastructure. Perhaps more importantly, it will demand broader recognition of the value of such work and collaboration between physicists, geochemists, and biologists working on the world\u27s seasonally freezing lakes and seas
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