6,011 research outputs found
Effects of reduced dissolved oxygen concentrations on physiology and fluorescence of hermatypic corals and benthic algae.
While shifts from coral to seaweed dominance have become increasingly common on coral reefs and factors triggering these shifts successively identified, the primary mechanisms involved in coral-algae interactions remain unclear. Amongst various potential mechanisms, algal exudates can mediate increases in microbial activity, leading to localized hypoxic conditions which may cause coral mortality in the direct vicinity. Most of the processes likely causing such algal exudate induced coral mortality have been quantified (e.g., labile organic matter release, increased microbial metabolism, decreased dissolved oxygen availability), yet little is known about how reduced dissolved oxygen concentrations affect competitive dynamics between seaweeds and corals. The goals of this study were to investigate the effects of different levels of oxygen including hypoxic conditions on a common hermatypic coral Acropora yongei and the common green alga Bryopsis pennata. Specifically, we examined how photosynthetic oxygen production, dark and daylight adapted quantum yield, intensity and anatomical distribution of the coral innate fluorescence, and visual estimates of health varied with differing background oxygen conditions. Our results showed that the algae were significantly more tolerant to extremely low oxygen concentrations (2-4 mg L(-1)) than corals. Furthermore corals could tolerate reduced oxygen concentrations, but only until a given threshold determined by a combination of exposure time and concentration. Exceeding this threshold led to rapid loss of coral tissue and mortality. This study concludes that hypoxia may indeed play a significant role, or in some cases may even be the main cause, for coral tissue loss during coral-algae interaction processes
Avian interactions with renewable energy infrastructure: An update
Energy infrastructure is widespread worldwide. Renewable energy technologies, which are expanding their footprint on the landscape and their contribution to energy availability, represent a different kind of infrastructure from extractive energy technologies. Although renewable energy sources may offer a āgreener alternativeā to traditional extractive energy sources, mounting evidence suggests that renewable energy infrastructure, and the transmission lines needed to convey energy from renewable energy facilities to users, may impact birds. Peer-reviewed literature historically has focused on the direct effects of electrocution and, to a lesser extent, collisions with overhead power systems, and on avian collisions at wind energy facilities, with less consideration of indirect effects or other energy sectors. Here, we review studies that have examined direct and indirect effects on birds at utility-scale onshore windand solar-energy facilities, including their associated transmission lines. Although both direct and indirect effects appear site-, species-, and infrastructure-specific, generalities across energy sectors are apparent. For example, largebodied species with high wing loading and relatively low maneuverability appear to be especially susceptible to direct effects of tall structures, and the risk of collision is likely greater when structures are placed perpendicular to flight paths or in areas of high use. Given that all infrastructure types result in direct loss or fragmentation of habitat and may affect the distribution of predators, indirect effects mediated by these mechanisms may be pervasive across energy facilities. When considered together, the direct and indirect effects of renewable energy facilities, and the transmission lines serving these facilities, are likely cumulative. Ultimately, cross-facility and cross-taxon meta-analyses will be necessary to fully understand the cumulative impacts of energy infrastructure on birds. Siting these facilities in a way that minimizes avian impacts will require an expanded understanding of how birds perceive facilities and the mechanisms underlying direct and indirect effects.
La infraestructura energĀ“etica estaĀ“ ampliamente distribuida en todo el mundo. Las tecnologĀ“ıas de energĀ“ıa renovable estaĀ“n expandiendo su huella en el paisaje y su contribuci Ā“on a la disponibilidad de energĀ“ıa, y representan un tipo diferente de infraestructura a la de las tecnologĀ“ıas extractivas de energĀ“ıa. Aunque las fuentes de energĀ“ıa renovable ofrecen una āāalternativa maĀ“s verdeāā en comparaci Ā“on con las fuentes tradicionales de extracci Ā“on de energĀ“ıa, existe bastante evidencia que sugiere que la infraestructura de energĀ“ıa renovable y las lĀ“ıneas de transmisi Ā“on necesarias para transportar la energĀ“ıa hacia los usuarios podrĀ“ıan afectar a las aves. La literatura cientĀ“ıfica tradicionalmente se ha enfocado en los efectos directos de la electrocuci Ā“on y, en menor medida, en las colisiones con los sistemas aĀ“ereos de energĀ“ıa y con las estructuras de energĀ“ıa e Ā“ olica. En cambio, ha habido escasa consideraci Ā“on de sus efectos indirectos y de otros sectores energĀ“ eticos. En este trabajo revisamos estudios que investigaron los efectos directos e indirectos sobre las aves a la escala de instalaciones terrestres de energĀ“ıa e Ā“ olica y solar, incluyendo sus lĀ“ıneas de transmisi Ā“ on. Aunque los efectos directos e indirectos parecen ser especĀ“ıficos para cada sitio, especie y tipo de energĀ“ıa, existen generalidades evidentes entre diferentes sectores energĀ“ eticos. Por ejemplo, las especies de mayor tamaĖ no, con alta carga alar y maniobrabilidad relativamente baja parecen ser especialmente susceptibles a los efectos directos de las estructuras altas, y el riesgo de colisi Ā“on probablemente es mayor cuando las estructuras se ubican perpendiculares al sentido del vuelo o en aĀ“reas con alto uso. Dado que todos los tipos de infraestructura resultan en la pĀ“erdida directa del haĀ“bitat o en su fragmentaci Ā“on y podrĀ“ıan afectar la distribuci Ā“on de los depredadores, los efectos indirectos mediados por estos mecanismos pueden ser comunes entre diferentes instalaciones energĀ“ eticas. Cuando se consideran en conjunto, los efectos directos e indirectos en las instalaciones de energĀ“ıa renovable y en las lĀ“ıneas de transmisi Ā“on asociadas probablemente son acumulativos. Finalmente, seraĀ“ necesario hacer meta anaĀ“ lisis a travĀ“es de varios tipos de instalaciones y taxones para entender completamente los impactos acumulativos de la infraestructura energĀ“etic
Visualization of oxygen distribution patterns caused by coral and algae.
Planar optodes were used to visualize oxygen distribution patterns associated with a coral reef associated green algae (Chaetomorpha sp.) and a hermatypic coral (Favia sp.) separately, as standalone organisms, and placed in close proximity mimicking coral-algal interactions. Oxygen patterns were assessed in light and dark conditions and under varying flow regimes. The images show discrete high oxygen concentration regions above the organisms during lighted periods and low oxygen in the dark. Size and orientation of these areas were dependent on flow regime. For corals and algae in close proximity the 2D optodes show areas of extremely low oxygen concentration at the interaction interfaces under both dark (18.4 Ā± 7.7 Āµmol O2 L(- 1)) and daylight (97.9 Ā± 27.5 Āµmol O2 L(- 1)) conditions. These images present the first two-dimensional visualization of oxygen gradients generated by benthic reef algae and corals under varying flow conditions and provide a 2D depiction of previously observed hypoxic zones at coral algae interfaces. This approach allows for visualization of locally confined, distinctive alterations of oxygen concentrations facilitated by benthic organisms and provides compelling evidence for hypoxic conditions at coral-algae interaction zones
Effects of Cognitive Status on Life Participation of Cancer Survivors
The purposes of this study were to identify the cognitive status of cancer survivors, determine the effect of cognitive status on function and participation in daily activities, and explore how cancer survivors perceive changes in their cognition. The study used a quantitative nonexperimental cross-sectional design. The participants included 35 cancer survivors from two different sites. Instruments included the Montreal Cognitive Assessment (MoCA) and the Reintegration to Normal Index-Postal Version (RNLI-P) in the measurement of cognitive impairment and functional performance respectively. Data were also collected with a supplemental questionnaire to explore participantsā perspectives on their cognitive difficulties and current function. The participant scores on the MoCA indicated cognitive impairment (Āµ= 25) and their scores on the RNLI-P demonstrated subpar reintegration (Āµ=9.64). Twenty-one participants answered the supplemental questionnaire. In content analysis of questionnaire responses, 17/21 participants reported some level of cognitive change related to cancer and cancer treatment. Data from an open-ended question were organized into four categories: decreased participation, more selective in activities, balance in activities, and cognitive changes. Study results indicate a large percentage of cancer survivors demonstrate mild cognitive impairment as well as changes in participation in instrumental activities of daily living
Mass landscapes of seven scorpion species: the first analyses of Australian species with 1,5-DAN matrix
Scorpion venoms have been studied for over fifty years; however, the majority of research has focussed primarily on medically important Buthidae species. Additionally, venoms of the estimated 200 species of scorpion native to Australia have received very little attention. The first venom mass profiles of six non-buthid and one buthid scorpion species are presented herein, four of which are endemic to Australia. While masses under 5 kDa dominated the venoms of all species, the buthid venom contained considerably more masses between 7 and 8 kDa than those of the non-buthids, corroborating the emergent trend that buthids are richer in long-chain neurotoxins than non-buthids. The Australian scorpion venom fractions were also analysed with the relatively new MALDI-ToF matrix 1,5-DAN. Over forty partial sequences were obtained, the majority of which are homologous to scorpion antimicrobials such as opistoporin and IsCT2. Overall, this study is the single most comprehensive mass spectrometric analysis of scorpion venom landscapes to date and provides an insight into untapped Australian species
A Diagnostic Examination of the Eastern Ontario and Western Quebec Wintertime Convection Event of 28 January 2010
The priority of an operational forecast center is to issue watches, warnings, and advisories to notify the public about the inherent risks and dangers of a particular event. Occasionally, events occur that do not meet advisory or warning criteria, but still have a substantial impact on human life and property. Short-lived snow bursts are a prime example of such a phenomenon. While these events are typically characterized by small snow accumulations, they often cause very low visibilities and rapidly deteriorating road conditions, both of which are a major hazard to motorists. On the afternoon of 28 January 2010, two such snow bursts moved through the Ottawa River valley and lower St. Lawrence River valley, and created havoc on area roads, resulting in collisions and injuries. Using the National Centers for Environmental Prediction (NCEP) North American Regional Reanalysis (NARR), these snow bursts were found to be associated with an approaching strong upper-tropospheric trough and the passage of an arctic front. While convection or squall lines are not common in January in Canada, snow bursts are shown to be associated with strong quasigeostrophic forcing for ascent and low-level frontogenesis, in the presence of both convective and conditional symmetric instability. Finally, this paper highlights the need for the development of a standard subadvisory criterion warning of short-lived but high-impact winter weather events, which operational forecasters can issue and quickly disseminate to the general public
Influence of coral and algal exudates on microbially mediated reef metabolism.
Benthic primary producers in tropical reef ecosystems can alter biogeochemical cycling and microbial processes in the surrounding seawater. In order to quantify these influences, we measured rates of photosynthesis, respiration, and dissolved organic carbon (DOC) exudate release by the dominant benthic primary producers (calcifying and non-calcifying macroalgae, turf-algae and corals) on reefs of Mo'orea French Polynesia. Subsequently, we examined planktonic and benthic microbial community response to these dissolved exudates by measuring bacterial growth rates and oxygen and DOC fluxes in dark and daylight incubation experiments. All benthic primary producers exuded significant quantities of DOC (roughly 10% of their daily fixed carbon) into the surrounding water over a diurnal cycle. The microbial community responses were dependent upon the source of the exudates and whether the inoculum of microbes included planktonic or planktonic plus benthic communities. The planktonic and benthic microbial communities in the unamended control treatments exhibited opposing influences on DO concentration where respiration dominated in treatments comprised solely of plankton and autotrophy dominated in treatments with benthic plus plankon microbial communities. Coral exudates (and associated inorganic nutrients) caused a shift towards a net autotrophic microbial metabolism by increasing the net production of oxygen by the benthic and decreasing the net consumption of oxygen by the planktonic microbial community. In contrast, the addition of algal exudates decreased the net primary production by the benthic communities and increased the net consumption of oxygen by the planktonic microbial community thereby resulting in a shift towards net heterotrophic community metabolism. When scaled up to the reef habitat, exudate-induced effects on microbial respiration did not outweigh the high oxygen production rates of benthic algae, such that reef areas dominated with benthic primary producers were always estimated to be net autotrophic. However, estimates of microbial consumption of DOC at the reef scale surpassed the DOC exudation rates suggesting net consumption of DOC at the reef-scale. In situ mesocosm experiments using custom-made benthic chambers placed over different types of benthic communities exhibited identical trends to those found in incubation experiments. Here we provide the first comprehensive dataset examining direct primary producer-induced, and indirect microbially mediated alterations of elemental cycling in both benthic and planktonic reef environments over diurnal cycles. Our results highlight the variability of the influence of different benthic primary producers on microbial metabolism in reef ecosystems and the potential implications for energy transfer to higher trophic levels during shifts from coral to algal dominance on reefs
Failure to communicate: Inefficiencies in voluntary incentive programs for private forest owners in Michigan
Coordinating forest management across thousands of nonindustrial private forest (NIPF) owners is a difficult yet necessary task for state land management agencies. Voluntary Incentive Programs (VIPs) can coordinate the decentralized activities of these owners in return for services or financial incentives. However, many VIPs typically have low enrollment. Our study investigates the implementation of VIPs to increase forest management coordination among NIPFs in Michigan. We present findings from 20 semi-structured interviews with leaders of state and local land management organizations, and government officials at state natural resource agencies, and contrast their answers with those recorded from 37 interviews of NIPF owners regarding their knowledge and attitudes toward VIPs. Our interviews highlight a critical disconnect between NIPF owner motivations and VIP incentives, as well as misallocated resources for VIP promotion by state agencies, driving low enrollment. At the core, low enrollment in VIPs is generated by inadequate communication between NIPF owners and program managers, along with distrust of government agency objectives. Viewing managers as āstreet level bureaucratsā, civil servants whose job discretion is impacted heavily by available resources, may increase our understanding of the issues plaguing VIPs and help identify improvements to VIP design and implementation
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Ocean circulation drifts in multi-millennial climate simulations: the role of salinity corrections and climate feedbacks
Low-resolution, complex general circulation models (GCMs) are valuable tools for studying the Earth system on multi-millennial timescales. However, slowly evolving salinity drifts can cause large shifts in climatic and oceanic regimes over thousands of years. We test two different schemes for neutralising unforced salinity drifts in the FAMOUS GCM: surface flux correction and volumetric flux correction. Although both methods successfully maintain a steady global mean salinity, local drifts and subsequent feedbacks promote cooling (āā4 Ā°C over 6000 years) and freshening (āā2 psu over 6000 years) in the North Atlantic Ocean, and gradual warming (āā0.2 Ā°C per millennium) and salinification (āā0.15 psu per millennium) in the North Pacific Ocean. Changes in the surface density in these regions affect the meridional overturning circulation (MOC), such that, after several millennia, the Atlantic MOC (AMOC) is in a collapsed state, and there is a strong, deep Pacific MOC (PMOC). Furthermore, the AMOC exhibits a period of metastability, which is only identifiable with run lengths in excess of 1500 years. We also compare simulations with two different land surface schemes, demonstrating that small biases in the surface climate may cause regional salinity drifts and significant shifts in the MOC (weakening of the AMOC and the initiation then invigoration of PMOC), even when the global hydrological cycle has been forcibly closed. Although there is no specific precursor to the simulated AMOC collapse, the northwest North Pacific and northeast North Atlantic are important areas that should be closely monitored for trends arising from such biases
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Highly accurate detection of ovarian cancer using CA125 but limited improvement with serum matrix-assisted laser desorption/ionization time-of-flight mass spectrometry profiling
Objectives: Our objective was to test the performance of CA125 in classifying serum samples from a cohort of malignant and benign ovarian cancers and age-matched healthy controls and to assess whether combining information from matrix-assisted laser desorption/ionization (MALDI) time-of-flight profiling could improve diagnostic performance.
Materials and Methods: Serum samples from women with ovarian neoplasms and healthy volunteers were subjected to CA125 assay and MALDI time-of-flight mass spectrometry (MS) profiling. Models were built from training data sets using discriminatory MALDI MS peaks in combination with CA125 values and tested their ability to classify blinded test samples. These were compared with models using CA125 threshold levels from 193 patients with ovarian cancer, 290 with benign neoplasm, and 2236 postmenopausal healthy controls.
Results: Using a CA125 cutoff of 30 U/mL, an overall sensitivity of 94.8% (96.6% specificity) was obtained when comparing malignancies versus healthy postmenopausal controls, whereas a cutoff of 65 U/mL provided a sensitivity of 83.9% (99.6% specificity). High classification accuracies were obtained for early-stage cancers (93.5% sensitivity). Reasons for high accuracies include recruitment bias, restriction to postmenopausal women, and inclusion of only primary invasive epithelial ovarian cancer cases. The combination of MS profiling information with CA125 did not significantly improve the specificity/accuracy compared with classifications on the basis of CA125 alone.
Conclusions: We report unexpectedly good performance of serum CA125 using threshold classification in discriminating healthy controls and women with benign masses from those with invasive ovarian cancer. This highlights the dependence of diagnostic tests on the characteristics of the study population and the crucial need for authors to provide sufficient relevant details to allow comparison. Our study also shows that MS profiling information adds little to diagnostic accuracy. This finding is in contrast with other reports and shows the limitations of serum MS profiling for biomarker discovery and as a diagnostic too
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