Kelp-associated microbes facilitate spatial subsidy in a detrital-based food web in a shoreline ecosystem

Microbes are ubiquitous but our knowledge of their effects on consumers is limited in benthic marine systems. Shorelines often form hotspots of microbial and detritivore activity due to the large amounts of detrital macrophytes that are exported from other coastal ecosystems, such as kelp forests, and accumulate in these systems. Shoreline ecosystems therefore provide a useful model system to examine microbial-detritivore interactions. We experimentally test whether bacteria in the biofilm of kelp provide a bottom-up influence on growth and reproductive output of detritivores in shorelines where detrital kelp accumulates, by manipulating the bacterial abundances on kelp (Ecklonia radiata). The growth rates for both male and female amphipods (Allorchestes compressa) were greater in treatments containing bacteria than those in which bacteria were reduced through antibiotic treatment, and this effect was greater for males offered aged kelp. The proportions of ovigerous females were greater when reared on kelp with intact bacteria, indicating a more rapid reproductive development in the presence of more bacteria. Bacterial abundance had little to no influence on nutrient content and palatability of kelp, based on tissue toughness, nitrogen and carbon content and C:N ratio. Thus, the most likely pathway for a microbial effect on detritivores was through feeding on kelp-associated bacteria. Regardless of the pathway, kelp-associated microbes have a strong influence on the fitness of a highly abundant detritivore that feeds preferentially on E. radiata in shoreline systems, and therefore form a hidden trophic step in this “brown” food web and a hotspot of secondary production

Kelp-associated microbes facilitate spatial subsidy in a detrital-based food web in a shoreline ecosystem [dataset]

The database compiles data (used in Singh et al. In Review, Frontiers in Marine Science) obtained from a laboratory experiment where Juvenile amphipods (Allorchesta compressa) were raised on fresh and aged kelp (Ecklonia radiata (“Type”) that had either been treated with antibiotics or left untreated (Treatment). Aged kelp had been maintained in an aquarium for two weeks to allow bacteria in the biofilm to increase to levels found in surf zones. Treated kelp represented kelp with reduced bacterial abundances, while control kelp represented kelp with natural abundances of bacteria. The experiment comprised 5 replicates for each treatment/type combination. The experiment ran over 6 weeks to examine growth of amphipods, and a further 2 weeks to examine reproductive traits (number of eggs and number of ovigorous females. Bacterial abundances were measured on kelp pieces at intervals throughout the experiment, along with tissue toughness, carbon (C) and nitrogen (N) content and C:N ratios to represent food palatability and quality

Core commitments for field trials of gene drive organisms

We must ensure that trials are scientifically, politically, and socially robust, publicly accountable, and widely transparent. Gene drive organisms (GDOs), whose genomes have been genetically engineered to spread a desired allele through a population, have the potential to transform the way societies address a wide range of daunting public health and environmental challenges. The development, testing, and release of GDOs, however, are complex and often controversial. A key challenge is to clarify the appropriate roles of developers and others actively engaged in work with GDOs in decision-making processes, and, in particular, how to establish partnerships with relevant authorities and other stakeholders. Several members of the gene drive community previously proposed safeguards for laboratory experiments with GDOs (1) that, in the absence of national or international guidelines, were considered essential for responsible laboratory work to proceed. Now, with GDO development advancing in laboratories (2–5), we envision similar safeguards for the potential next step: ecologically and/or genetically confined field trials to further assess the performance of GDOs. A GDO’s propensity to spread necessitates well-developed criteria for field trials to assess its potential impacts (6). We, as a multidisciplinary group of GDO developers, ecologists, conservation biologists, and experts in social science, ethics, and policy, outline commitments below that we deem critical for responsible conduct of a field trial and to ensure that these technologies, if they are introduced, serve the public interest. Includes Supplementary materials

Deployment of innovative genetic vector control strategies: progress on regulatory and biosafety aspects, capacity building and development of best-practice guidance

In the ongoing fight against vectors of human diseases, disease endemic countries (DECs) may soon benefit from innovative control strategies involving modified insect vectors. For instance, three promising methods (viz. RIDL® [Release of Insects with a Dominant Lethal], Wolbachia infection, and refractory mosquito technology) are being developed by researchers around the world to combat Aedes aegypti, the primary mosquito vector of viral fevers such as dengue (serotypes 1-4), chikungunya and yellow fever. Some of these techniques are already being extended to other vectors such as Aedes albopictus (the secondary vector of these diseases) and Anopheles mosquito species that transmit malaria. To enable DECs to take advantage of these promising methods, initiatives are underway that relate to biosafety, risk assessment and management, and ethical-social-cultural (ESC) aspects to consider prior to and during the possible deployment of these technologies as part of an integrated vector control programme. This is a brief overview of the objectives and timelines of some of the initiatives being championed by international institutions, including the United Nations Development Programme (UNDP), the World Health Organization (WHO) and the Grand Challenges in Global Health (GCGH) initiative co-sponsored by the Bill & Melinda Gates Foundation

Uproar on Campus: Student Protests in the Vietnam War Era

The Vietnam War was one of the most polarizing events in United States history. Protesters angered by a decade of controversial policy decisions in Vietnam opposed what they believed to be an unfair and corrupt political system waging an unpopular war. As the antiwar movement began to gain momentum in the late 1960s and early 1970s, college students took leading roles, protesting not only against the war, but also against conventional forms of authority and social norms. Student protesters embraced a philosophy of free love, and peace and justice for all that had its roots in the radical counterculture movement that started in the early 1960s. The Vietnam War opened an ideological rift between Americans. The radical ideas of student protesters, and the antiwar movement more broadly, met opposition from the US government, as well as from supporters of the war. Americans on both side of this divide banded together to print and distribute materials across the country in the hopes of gaining support and recognition for their respective causes. The artifacts in this exhibit are drawn from the Radical Pamphlets Collection housed in Gettysburg College’s Musselman Library. These artifacts have been selected to provide a taste of what it might have been like to be a college student during the Vietnam War era

Seagrass organic carbon stocks show minimal variation over short time scales in a heterogeneous subtropical seascape

Blue carbon initiatives require accurate monitoring of carbon stocks. We examined sources of variability in seagrass organic carbon (Corg) stocks, contrasting spatial with short temporal scales. Seagrass morphology and sediment Corg stocks were measured from biomass and shallow sediment cores collected in Moreton Bay, Australia. Samples were collected between 2012 and 2013, from a total of 77 sites that spanned a gradient of water turbidity. Environmental measures of water quality between 2000 and 2013 revealed strong seasonal fluctuations from summer to winter, yet seagrass biomass exhibited no temporal variation. There was no temporal variability in Corg stocks, other than below ground biomass stocks were slightly higher in June 2013. Seagrass locations were grouped into riverine, coastal, and seagrass loss locations and short temporal variability of Corg stocks was analysed within these categories to provide clearer insights into temporal patterns. Above ground Corg stocks were similar between coastal and riverine meadows. Below ground Corg stocks were highest in coastal meadows, followed by riverine meadows. Sediment Corg stocks within riverine meadows were much higher than at coastal meadows and areas of seagrass loss, with no difference in sediment Corg stocks between these last two categories. Riverine seagrass meadows, of higher turbidity, had greater total Corg stocks than meadows in offshore areas irrespective of time. We suggest that Corg stock assessment should prioritise sampling over spatial gradients, but repeated monitoring over short time scales is less likely to be warranted if environmental conditions remain stable.UCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias Básicas::Centro de Investigación en Ciencias del Mar y Limnología (CIMAR

Core commitments for field trials of gene drive organisms

Gene drive organisms (GDOs), whose genomes have been genetically engineered to spread a desired allele through a population, have the potential to transform the way societies address a wide range of daunting public health and environmental challenges. The development, testing, and release of GDOs, however, are complex and often controversial. A key challenge is to clarify the appropriate roles of developers and others actively engaged in work with GDOs in decision-making processes, and, in particular, how to establish partnerships with relevant authorities and other stakeholders. Several members of the gene drive community previously proposed safeguards for laboratory experiments with GDOs (1) that, in the absence of national or international guidelines, were considered essential for responsible laboratory work to proceed. Now, with GDO development advancing in laboratories (2–5), we envision similar safeguards for the potential next step: ecologically and/or genetically confined field trials to further assess the performance of GDOs. A GDO\u27s propensity to spread necessitates well-developed criteria for field trials to assess its potential impacts (6). We, as a multidisciplinary group of GDO developers, ecologists, conservation biologists, and experts in social science, ethics, and policy, outline commitments below that we deem critical for responsible conduct of a field trial and to ensure that these technologies, if they are introduced, serve the public interest