22 research outputs found

    Predicting the Electron Requirement for Carbon Fixation in Seas and Oceans

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    Marine phytoplankton account for about 50% of all global net primary productivity (NPP). Active fluorometry, mainly Fast Repetition Rate fluorometry (FRRf), has been advocated as means of providing high resolution estimates of NPP. However, not measuring CO2-fixation directly, FRRf instead provides photosynthetic quantum efficiency estimates from which electron transfer rates (ETR) and ultimately CO2-fixation rates can be derived. Consequently, conversions of ETRs to CO2-fixation requires knowledge of the electron requirement for carbon fixation (Ίe,C, ETR/CO2 uptake rate) and its dependence on environmental gradients. Such knowledge is critical for large scale implementation of active fluorescence to better characterise CO2-uptake. Here we examine the variability of experimentally determined Ίe,C values in relation to key environmental variables with the aim of developing new working algorithms for the calculation of Ίe,C from environmental variables. Coincident FRRf and 14C-uptake and environmental data from 14 studies covering 12 marine regions were analysed via a meta-analytical, non-parametric, multivariate approach. Combining all studies, Ίe,C varied between 1.15 and 54.2 mol e- (mol C)-1 with a mean of 10.9±6.91 mol e- mol C)-1. Although variability of Ίe,C was related to environmental gradients at global scales, region-specific analyses provided far improved predictive capability. However, use of regional Ίe,C algorithms requires objective means of defining regions of interest, which remains challenging. Considering individual studies and specific small-scale regions, temperature, nutrient and light availability were correlated with Ίe,C albeit to varying degrees and depending on the study/region and the composition of the extant phytoplankton community. At the level of large biogeographic regions and distinct water masses, Ίe,C was related to nutrient availability, chlorophyll, as well as temperature and/or salinity in most regions, while light availability was also important in Baltic Sea and shelf waters. The novel Ίe,C algorithms provide a major step forward for widespread fluorometry-based NPP estimates and highlight the need for further studying the natural variability of Ίe,C to verify and develop algorithms with improved accuracy. © 2013 Lawrenz et al

    CRISPR in context : towards a socially responsible debate on embryo editing

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    Following the birth in 2018 of two babies from embryos altered using CRISPR-Cas9, human germline gene editing (GGE) moved from abstract concern to reality. He Jiankui, the scientist responsible, has been roundly condemned by most scientific, legal and ethical commentators. However, opinions remain divided on whether GGE could be acceptably used in the future, and how, or if it should be prohibited entirely. The many reviews, summits, positions statements and high-level meetings that have accompanied the emergence of CRISPR technology acknowledge this, calling for greater public engagement to help reach a consensus on how to proceed. These calls are laudable but far from unproblematic. Consensus is not only hugely challenging to reach, but difficult to measure and to know when it might be achieved. Engagement is clearly desirable, but engagement strategies need to avoid the limitations of previous encounters between publics and biotechnology. Here we set CRISPR in the context of the biotechnology and fertility industries to illustrate the lessons to be learned. In particular we demonstrate the importance of avoiding a ‘deficit mode’ in which resistance is attributed to a lack of public understanding of science, addressing the separation of technical safety criteria from ethical and social matters, and ensuring the scope of the debate includes the political-economic context in which science is conducted and new products and services are brought to market. Through this history, we draw on Mary Douglas’ classic anthropological notion of ‘matter out of place’ to explain why biotechnologies evoke feelings of unease and anxiety, and recommend this as a model for rehabilitating lay apprehension about novel biological technologies as legitimate matters of concern in future engagement exercises about GGE

    A vision for actionable science in a pandemic

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    Advances in remote sensing of great lakes algal blooms

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    Many regions of the Great Lakes now see recurring cyanobacterial harmful algal blooms (cyanoHABs), with documented repercussions for ecosystem services, public health, and ecosystem integrity. Early detection and comprehensive monitoring of cyanoHABs are fundamental to their effective management and mitigation of detrimental impacts. Satellite remote sensing has provided the means by which algal blooms in the Great Lakes can be observed with unprecedented frequency and spatial coverage. Algorithms have been developed and validated; fully automated data processing streams have been rendered operational; and stakeholders have been engaged in order to develop user-friendly end products. Such products have been integral in providing near-real-time monitoring of bloom conditions, documenting spatiotemporal trends, improving understanding of environmental drivers of blooms, and guiding nutrient management actions. In this chapter we present background information on remote sensing of algal blooms, document the current state of knowledge with a focus on Lake Erie, and discuss remote sensing products available to the Great Lakes community
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