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

Bipartite partial duals and circuits in medial graphs

It is well known that a plane graph is Eulerian if and only if its geometric dual is bipartite. We extend this result to partial duals of plane graphs. We then characterize all bipartite partial duals of a plane graph in terms of oriented circuits in its medial graph.Comment: v2: minor changes. To appear in Combinatoric

Distribution of copper and zinc in oysters and sediments from three coastal-plain estuaries.

Copper and zinc were analyzed in oysters (Crassostrea virginica) from the Newport River estuary, North Carolina, and the Rappahannock River estuary, Virginia. Results indicated that a concentration gradient existed, higher concentrations of metals being found in animals living in fresher waters as was shown previously for oysters in the James, York, and Rappahannock estuaries in Virginia. Absorbed, precipitatcd-coprecipitated, and organic fractions of copper and zinc in the \u3c63-μm portion of the sediments from the Rappahannock and York rivers and estuaries were estimated from collections made in January 1972 and June 1973. These sediment data are discussed for both estuarine systems and are compared with metal concentrations in oysters. These comparisons indicated that the concentration gradient found in oysters does not appear to be related to the distribution of copper and zinc in the sediments. Alternative explanations for the inverse relationships between concentrations of copper and zinc in oysters and salinity arc given.https://scholarworks.wm.edu/vimsbooks/1146/thumbnail.jp

Identification of stable endogenous reference genes for real-time PCR in the human fetal gonad using an external standard technique

Peer reviewedPostprin

The Gibbs paradox, Black hole entropy and the thermodynamics of isolated horizons

This letter presents a new, solely thermodynamical argument for considering the states of the quantum isolated horizon of a black hole as distinguishable. We claim that only if the states are distinguishable, the thermodynamic entropy is an extensive quantity and can be well-defined. To show this, we make a comparison with a classical ideal gas system whose statistical description makes only sense if an additional 1/N!-factor is included in the state counting in order to cure the Gibbs paradox. The case of the statistical description of a quantum isolated horizon is elaborated, to make the claim evident.Comment: 8 pages, closest to the published version; taken from the author's diploma thesi

Considerations for accurate gene expression measurement by reverse transcription quantitative PCR when analysing clinical samples

Reverse transcription quantitative PCR is an established, simple and effective method for RNA measurement. However, technical standardisation challenges combined with frequent insufficient experimental detail render replication of many published findings challenging. Consequently, without adequate consideration of experimental standardisation, such findings may be sufficient for a given publication but cannot be translated to wider clinical application. This article builds on earlier standardisation work and the MIQE guidelines, discussing processes that need consideration for accurate, reproducible analysis when dealing with patient samples. By applying considerations common to the science of measurement (metrology), one can maximise the impact of gene expression studies, increasing the likelihood of their translation to clinical tools

Ecological effects of experimental oil spills in eastern coastal plain estuaries

Ecological effects / M.E. Bender, E.A. Shearls & R.J. Huggett -- Chemical fate / R.H. Bieri, M.K. Cueman & V.C. Stamoudis -- Microbial responses / H. Kator

Tributyltin in whole water and sediment collected from marinas and the Hampton Roads area in the southern Chesapeake Bay : a final report

This report presents data gathered in a program designed to monitor tributyltin (TBT) levels in water and sediment from areas in the southern Chesapeake Bay which experience high boating activities. The concentrations reported will hopefully give an insight into the extent and magnitude of TBT contamination in these areas