Phosphate oxygen isotopes within aquatic ecosystems:global data synthesis and future research priorities

The oxygen isotope ratio of dissolved inorganic phosphate (δ18Op) represents a novel and potentially powerful stable isotope tracer for biogeochemical research. Analysis of δ18Op may offer new insights into the relative importance of different sources of phosphorus within natural ecosystems. Due to the isotope fractionations that occur alongside the metabolism of phosphorus, δ18Op could also be used to better understand the intracellular and extracellular reaction mechanisms that control phosphorus cycling. In this review focussed on aquatic ecosystems, we examine the theoretical basis to using stable oxygen isotopes within phosphorus research.We consider the methodological challenges involved in accurately determining δ18Op, given aquatic matrices in which potential sources of contaminant oxygen are ubiquitous. Finally,we synthesise the existing global data regarding δ18Op in aquatic ecosystems, concluding by identifying four key areas for future development of δ18Op research. Through this synthesis, we seek to stimulate broader interest in the use of δ18Op to address the significant research and management challenges that continue to surround the stewardship of phosphorus

Pictorial history of the 447th Bombardment Group (H)

Published as an unofficial history of the Group\u27s activities from activation to completion of 258 Combat Missions in the European Theatre of Operations, through the courtesy of the Officers\u27 Club, whose Board of Governors made available funds to apply against publication costs on copies for distribution to members of the 447th Group who were on its rosters as of the dates of departure from the E. T. 0. for the Z. of I. This pictorial, and unofficial, history of the 447th Bombardment Group is not as complete as its editors would have liked it to be, due to the fact that the work of preparing and assembling it had to be done by the very limited staff on hand at Drew Field, Florida, whose primary task was the job of deactivating the Group. So it was prepared amid considerable confusion by the short handed staff and using as much of the material as could be found among the Group and Squadron records. The editors have used every possible photo whether of personnel, combat crews, ground crews, social activities, etc. that could be found. Without doubt, many other photos exist, but these were not on hand at the time the history was prepared. -The Editors [Captains Surridge and Dooley]https://digicom.bpl.lib.me.us/ww_reg_his/1108/thumbnail.jp

The effect of colour vision status on the detection and selection of fruits by tamarins (Saguinus spp.)

The evolution of trichromatic colour vision by the majority of anthropoid primates has been linked to the efficient detection and selection of food, particularly ripe fruits among leaves in dappled light. Modelling of visual signals has shown that trichromats should be more efficient than dichromats at distinguishing both fruits from leaves and ripe from unripe fruits. This prediction is tested in a controlled captive setting using stimuli recreated from those actually encountered by wild tamarins (Saguinus spp.). Dietary data and reflectance spectra of Abuta fluminum fruits eaten by wild saddleback (Saguinus fuscicollis) and moustached (Saguinus mystax) tamarins and their associated leaves were collected in Peru. A. fluminum leaves, and fruits in three stages of ripeness, were reproduced and presented to captive saddleback and red-bellied tamarins (Saguinus labiatus). Trichromats were quicker to learn the task and were more efficient at selecting ripe fruits than were dichromats. This is the first time that a trichromatic foraging advantage has been demonstrated for monkeys using naturalistic stimuli with the same chromatic properties as those encountered by wild animal

Responses of selected biota after biostimulation of a vegetable oil spill in the Con Joubert Bird Sanctuary wetland: A pilot study

An investigation on the effect of a vegetable oil spill was conducted on the biological diversity of the Con Joubert Bird Sanctuary wetland in South Africa before and after biostimulation with different concentrations of fertilizer during 2008. Biostimulation responses were analyzed 30 days after different concentrations of fertilizer were applied to the freshwater wetland at three selected sampling sites. The Con Joubert Bird Sanctuary wetland showed a high degree of contamination after a vegetable oil spill, resulting in a large volume of vegetable oil in the sediment and water column, respectively. Vegetable oil contents differed at each sampling site before biostimulation and each site showed variable responses after biostimulation. In this study, biostimulation results displayed a high yield of microbial activity and vegetable oil degradation at site one and two respectively. However, the degradation of the high vegetable oil concentrations within the sediments at sampling site 3 may have been hampered or retarded by the polymerized state of the vegetable oil. The phytoplankton, protozoan, macroinvertebrates and microorganisms assemblage were affected and showed little improvement at site 3, even after biostimulation with the high fertilizer concentration of 800 g/m2, in comparison to sites 1 and 2 which showed greater biological activities and degradation of vegetable oil.Keywords: Biostimulation, vegetable oil spill, fresh water wetlandAfrican Journal of Biotechnology Vol. 12(4), pp. 385-39

Development and initial application of δ18Op to understand phosphorus cycling in river, lake and groundwater ecosystems.

Variation in the stable isotope composition of oxygen within dissolved phosphate (δ18Op) represents a novel and potentially powerful environmental tracer. In freshwater, marine and terrestrial ecosystems, δ18Op can act as an inherent label for the sources of phosphorus and the extent to which phosphorus from different sources is metabolised. This paper focuses on the methodological development and initial application of δ18Op across a range of freshwater ecosystems. Initially, we report modifications to the analytical protocol for δ18Op that are designed to minimise incorporation of contaminant oxygen in the final silver phosphate precipitate prior to pyrolysis. This is critical given the range of possible sources of contaminant oxygen within freshwater matrices. Subsequently, we consider the potential utility of δ18Op through application of the technique within a range of freshwater ecosystems in England, UK. Firstly, we characterise δ18Op in river water and effluents from Sewage Treatment Works (STW), and examine the opportunity to use the 18Op of STW effluents to trace the entry and downstream fate of phosphorus from these point sources in rivers. Secondly, we analyse δ18Op to gain insights into variations in the sources and biological cycling of phosphorus in a seasonally stratified lake ecosystem. Thirdly, we characterise δ18Op in shallow and deep groundwater samples, considering whether δ18Op might provide evidence for variation in source and extent of metabolism for phosphorus in groundwater ecosystems. Taken together, these data extend the catalogue of δ18Op in freshwater ecosystems, and further the scope of δ18Op as a tool to better understand phosphorus biogeochemistry

Isotopic fingerprint for phosphorus in drinking water supplies

Phosphate dosing of drinking water supplies, coupled with leakage from distribution networks, represents a significant input of phosphorus to the environment. The oxygen isotope composition of phosphate (δ18OPO4), a novel stable isotope tracer for phosphorus, offers new opportunities to understand the importance of phosphorus derived from sources such as drinking water. We report the first assessment of δ18OPO4 within drinking water supplies. A total of 40 samples from phosphate-dosed distribution networks were analyzed from across England and Wales. In addition, samples of the source orthophosphoric acid used for dosing were also analyzed. Two distinct isotopic signatures for drinking water were identified (average = +13.2 or +19.7‰), primarily determined by δ18OPO4 of the source acid (average = +12.4 or +19.7‰). Dependent upon the source acid used, drinking water δ18OPO4 appears isotopically distinct from a number of other phosphorus sources. Isotopic offsets from the source acid ranging from −0.9 to +2.8‰ were observed. There was little evidence that equilibrium isotope fractionation dominated within the networks, with offsets from temperature-dependent equilibrium ranging from −4.8 to +4.2‰. While partial equilibrium fractionation may have occurred, kinetic effects associated with microbial uptake of phosphorus or abiotic sorption and dissolution reactions may also contribute to δ18OPO4 within drinking water supplies

Effect of colour vision status on insect prey capture efficiency of captive and wild tamarins (Saguinus spp.)

The colour vision polymorphism of most New World primates is a model system to study the function of colour vision. Theories for the evolution of primate trichromacy focus on the efficient detection and selection of ripe fruits and young leaves amongst mature leaves, when trichromats are likely to be better than dichromats. We provide data on whether colour vision status affects insect capture in primates. Trichromatic tamarins (Saguinus spp.) catch more prey than dichromats, but dichromats catch a greater proportion of camouflaged prey than trichromats. The prey caught does not differ in size between the two visual phenotypes. Thus two factors may contribute to the maintenance of genetic polymorphism of middle- to long-wavelength photopigments in Platyrrhines: the advantage in finding fruit and leaves, which supports the maintenance of the polymorphism through a heterozygote advantage, and the dichromats’ exploitation of different (e.g., camouflaged) food, which results in frequency-dependent selection on the different colour vision phenotypes

A multi-stable isotope framework to understand eutrophication in aquatic ecosystems

Eutrophication is a globally significant challenge facing aquatic ecosystems, associated with human induced enrichment of these ecosystems with nitrogen (N) and phosphorus (P). However, the limited availability of inherent labels for P and N has constrained understanding of the triggers for eutrophication in natural ecosystems and appropriate targeting of management responses. This paper proposes and evaluates a new multi-stable isotope framework that offers inherent labels to track biogeochemical reactions governing both P and N in natural ecosystems. The framework couples highly novel analysis of the oxygen isotope composition of phosphate (δ18OPO4) with dual isotope analysis of oxygen and N within nitrate (δ15NNO3, δ18ONO3) and with stable N isotope analysis in ammonium (δ15NNH4). The River Beult in England is used as an exemplar system for initial evaluation of this framework. Our data demonstrate the potential to use stable isotope labels to track the input and downstream fate of nutrients from point sources, on the basis of isotopic differentiation for both P and N between river water and waste water treatment work effluent (mean difference = +1.7‰ for δ18OPO4; +15.5‰ for δ15NNH4 (under high flow); +7.3‰ for δ18ONO3 and +4.4‰ for δ15NNO3). Stable isotope data reveal nutrient inputs to the river upstream of the waste water treatment works that are consistent with partially denitrified sewage or livestock sources of nitrate (δ15NNO3 range = +11.5 to +13.1‰) and with agricultural sources of phosphate (δ18OPO4 range = +16.6 to +19.0‰). The importance of abiotic and metabolic processes for the in-river fate of N and P are also explored through the stable isotope framework. Microbial uptake of ammonium to meet metabolic demand for N is suggested by substantial enrichment of δ15NNH4 (by 10.2‰ over a 100 m reach) under summer low flow conditions. Whilst the concentration of both nitrate and phosphate decreased substantially along the same reach, the stable isotope composition of these ions did not vary significantly, indicating that concentration changes are likely driven by abiotic processes of dilution or sorption. The in-river stable isotope composition and the concentration of P and N were also largely constant downstream of the waste water treatment works, indicating that effluent-derived nutrients were not strongly coupled to metabolism along this in-river transect. Combined with in-situ and laboratory hydrochemical data, we believe that a multi-stable isotope framework represents a powerful approach for understanding and managing eutrophication in natural aquatic ecosystems

Inefficiency and Environmental Risks associated with Nutrient Use in Agriculture within China and the UK

The stocks and flows of nitrogen (N) and phosphorus (P) were quantified for five case studies, representing contrasting agricultural systems in China and the UK. The input of nutrients exceeded the output of nutrients in agricultural products for all five systems, although to varying degrees between individual case studies.Excessive input of nutrients for each system increases the risk of negative environmental impacts on soil, air and water quality. Soils accumulate nutrient stocks due to excessive nutrient inputs, representing an under-exploited nutrient reserve that could contribute to future agriculture production. Livestock and crop production are increasingly disconnected in China. Manure application was limited to high-value fruit and vegetable crops in the systems analysed, but often without adequate accounting for the nutrient content of the applied manure.Pathways to improve the efficiency of nutrient use are identified

Delivering improved nutrient stewardship in China: the knowledge, attitudes and practices of farmers and advisers

There is a need to assess and re-orient agricultural knowledge and innovation systems (AKIS) in China, aiming to rebalance the importance of productivity alongside the stewardship of farm inputs, natural resources and broader protection of the environment; a new ethos is needed. Analysis and recommendations for this are provided