Continuous ‘Passive’ flow-proportional monitoring of drainage using a new modified Sutro weir (MSW) unit

In view of their crucial role in water and solute transport, enhanced monitoring of agricultural subsurface drain tile systems is important for adequate water quality management. However, existing monitoring techniques for flow and contaminant loads from tile drains are expensive and labour intensive. The aim of this study was to develop a cost-effective and simple method for monitoring loads from tile drains. The Flowcap is a modified Sutro weir (MSW) unit that can be attached to the outlet of tile drains. It is capable of registering total flow, contaminant loads and flow-averaged concentrations. The MSW builds on a modern passive sampling technique that responds to hydraulic pressure and measures average concentrations over time (days to months) for various substances. Mounting the samplers in the MSW allowed a flow-proportional part of the drainage to be sampled. Laboratory testing yielded high linear correlation between the accumulated sampler flow, q _total, and accumulated drainage flow, Q _total (r ²?>?0.96). The slope of these correlations was used to calculate the total drainage discharge from the sampled volume, and therefore contaminant load. A calibration of the MSW under controlled laboratory condition was needed before interpretation of the monitoring results was possible. The MSW does not require a shed, electricity, or maintenance. This enables large-scale monitoring of contaminant loads via tile drains, which can improve contaminant transport models and yield valuable information for the selection and evaluation of mitigation options to improve water quality. Results from this type of monitoring can provide data for the evaluation and optimisation of best management practices in agriculture in order to produce the highest yield without water quality and recipient surface waters being compromised.     

Occurrence of antimicrobials in animal manure-amended soils around the breeding farms: The case of the Saigon River (southern Vietnam)

The excessive use of antimicrobials in animal rearing and the associated environmental hazards have become a pressing issue. Animal agriculture is often viewed as a significant contributor to environmental degradation due to the residues of antimicrobials. It is a common practice to use livestock waste as a soil enhancer in farming. Despite some research into antimicrobials, there is room for more comprehensive data regarding these pollutants in animal farming environments. A handful of earlier studies have identified antimicrobials in animal waste. This research undertook the task of examining and evaluating soils amended with animal waste (from chickens, cows, and pigs) for the presence of seven specific antimicrobials. The antimicrobials under scrutiny included trimethoprim (TRI), ormethoprim (ORM), ofloxacin (OFL), norfloxacin (NOR), tetracycline (TET), chlortetracycline (CTE), and tylosin (TLS). Soil samples were collected from areas surrounding breeding farms located upstream of the Sai Gon River. These samples were then subjected to laboratory analysis, which involved solid-phase extraction using ultrasonic waves and the application of high-performance liquid chromatography-tandem mass spectrometry (LCMS/MS) to identify the antimicrobials. TRI, which had the highest average concentration (2.603–91.304 μg/kg), and OFL, with the second highest average concentration (1.815–15.832 μg/kg), were detected in all soil samples amended with manure. CTE, with the third highest average concentration, was found in soils amended with cow and pig waste (1.625–15.486 μg/kg). ORM and TE, with lower average concentrations (0.595–1.318 μ and 11.537–13.569 μg/kg, respectively), were only detected in soils amended with chicken waste, while NOR was only found in soils amended with cow waste. These findings indicate that the use of antimicrobials in animal farming can negatively impact the soil ecosystem. Consequently, these results can contribute to the creation of guidelines for monitoring antimicrobial residues in agricultural ecosystems.     

How honeybees perceive communication dances,studied by means of a mechanical model

Summary A mechanical model of a dancing honeybee was used to investigate the role of various components of the wagging dance in the transfer of information to follower bees. The model simulates the dance, carries a scent, and has an acoustic near-field similar to that of live dancers. The movements of the model are controlled by a computer, and selected components of the dance can be manipulated independently of others. The number of bees approaching scented baits at various distances and directions from the hive was observed, both during simulated normal dances and dances in which different components provided potentially conflicting information about the location of the food. The results indicate that the wagging run is the master component of the dance. The figure-of-eight dance path does not seem to convey information. Both sound and wagging must be present in the dance, but no specific roles were found for these components. Both sound and wagging convey information about distance and direction, and they appear to be largely redundant. Offprint requests to: A. Michelsen     

Echolocation in two very small bats from Thailand Craseonycteris thonglongyai and Myotis siligorensis

Summary The echolocation and hunting behavior of two very small bats, Craseonycteris thonglongyai (Hill) and Myotis siligorensis (Horsfield), from Thailand, were investigated using multiflash photographs, video, and high-speed tape recordings with a microphone array that allowed determination of distance and direction to the bats. C. thonglongyai is the world's smallest mammal and M. siligorensis is only slightly larger. Both bats hunted insects in open areas. The search signals of C. thonglongyai were 3.5 ms long multiharmonic constant frequency (CF) signals with a prominent second harmonic at 73 kHz repeated at around 22 Hz. The band width (BW) of the short terminal frequency modulated (FM) sweep increased during the very short approach phase. In the final buzz the CF component disappeared, the duration decreased to 0.2 ms, and the repetition rate increased to 215 Hz (Figs. 2, 3, 4). There was no drop in frequency in the buzz. The video recordings of C. thonglongyai indicated that it seizes insects directly with the mouth (Fig. 1). M. siligorensis produced 5.4 ms long CF search signals at 66 kHz. The repetition rate was around 13 Hz. In the approach phase an initial broad band FM sweep was added. The buzz consisted of two phases, buzz I and buzz II. Buzz 11 was characterized by short cry durations (around 0.3 ms), a constant high repetition rate (185 Hz), a distinct drop in frequency, and a prominent second harmonic (Figs. 5, 6, 7). The drop in frequency, apparently typical of vespertilionid bats, has been explained by physiological limitations in sound production. However, C. thonglongyai produced very short signals at very high repetition rates without any frequency drop. The drop may be of adaptive value since it enables M. siligorensis to produce very short signals with high sweep rates. The drop moves the pronounced second harmonic into the frequency range of most interest to the bat (Fig. 7D). The sweep rate in this frequency range may now increase to twice the maximum rate that the vocal cords can produce directly. C. thonglongyai and M. siligorensis belong to different superfamilies, Emballonuroidea and Vespertilionoidea, respectively. In spite of their phylogenetic distance they produce strikingly similar search signals of narrow BW around 70 kHz with high source levels (100–115 dB peSPL peak equivalent sound pressure level). We argue that the signal resemblance is due to the similarity in size and hunting behavior of the two bats both hunting insects in open areas. High frequencies are heavily attenuated in air, but because of their small size the bats are restricted to hunting small insects which only reflect echoes at high frequencies. Thus, the emitted frequency is probably the lowest possible given the prey size. Hence, the two bats can only maximize the range of their sonar by decreasing the BW and emitting high intensities. Correspondence to: A. Surlykke     

The oil and gas sector: from climate laggard to climate leader?

ABSTRACT

The oil and gas industry has traditionally been reticent to engage with the issues surrounding climate change, typically being cast as a laggard. Yet, over recent years, the sector has begun taking on a more active role in climate governance, doing so in a variety of capacities – as initiators, catalysts and participants in industry-led or multi-stakeholder efforts. The Oil and Gas Climate Initiative is reviewed, as a case study to illustrate emerging climate leadership within the global oil and gas industry. In 2015, its members committed to a two-degree pathway. The paucity of research on the nascent role of oil and gas firms in climate governance is addressed.     

An approach for particle sinking velocity measurements in the 3–400?μm size range and considerations on the effect of temperature on sinking rates

The flux of organic particles below the mixed layer is one major pathway of carbon from the surface into the deep ocean. The magnitude of this export flux depends on two major processes—remineralization rates and sinking velocities. Here, we present an efficient method to measure sinking velocities of particles in the size range from approximately 3–400?μm by means of video microscopy (FlowCAM^?). The method allows rapid measurement and automated analysis of mixed samples and was tested with polystyrene beads, different phytoplankton species, and sediment trap material. Sinking velocities of polystyrene beads were close to theoretical values calculated from Stokes’ Law. Sinking velocities of the investigated phytoplankton species were in reasonable agreement with published literature values and sinking velocities of material collected in sediment trap increased with particle size. Temperature had a strong effect on sinking velocities due to its influence on seawater viscosity and density. An increase in 9?°C led to a measured increase in sinking velocities of ~40?%. According to this temperature effect, an average temperature increase in 2?°C as projected for the sea surface by the end of this century could increase sinking velocities by about 6?% which might have feedbacks on carbon export into the deep ocean.     

Climate vs. soil factors in local adaptation of two common plant species

Evolutionary theory suggests that divergent natural selection in heterogeneous environments can result in locally adapted plant genotypes. To understand local adaptation it is important to study the ecological factors responsible for divergent selection. At a continental scale, variation in climate can be important while at a local scale soil properties could also play a role. We designed an experiment aimed to disentangle the role of climate and (abiotic and biotic) soil properties in local adaptation of two common plant species. A grass (Holcus lanatus) and a legume (Lotus corniculatus), as well as their local soils, were reciprocally transplanted between three sites across an Atlantic-Continental gradient in Europe and grown in common gardens in either their home soil or foreign soils. Growth and reproductive traits were measured over two growing seasons. In both species, we found significant environmental and genetic effects on most of the growth and reproductive traits and a significant interaction between the two environmental effects of soil and climate. The grass species showed significant home site advantage in most of the fitness components, which indicated adaptation to climate. We found no indication that the grass was adapted to local soil conditions. The legume showed a significant home soil advantage for number of fruits only and thus a weak indication of adaptation to soil and no adaptation to climate. Our results show that the importance of climate and soil factors as drivers of local adaptation is species-dependent. This could be related to differences in interactions between plant species and soil biota.     

Working in small enterprises – Is there a special risk?

Ownership structure is an important factor. For independent enterprises, the ergonomic, physical and chemical work environment is more hazardous in small enterprises than in large ones. For enterprises that are part of a larger organization, the work environment tends to be more hazardous in large enterprises when controlling for the same factors. For the psychosocial factors, the trend is different – better in small than in large enterprises independent of ownership. In all enterprises, both public and private, the quality of health and safety management systems and workplace assessment is remarkably higher in large than in small enterprises.These differences in work environment for small and large enterprises have been studied in the ‘Danish Work Environment Cohort Study’ and ‘Surveillance of health and safety activities in enterprises’. These datasets are linked together to a reliable database with data on work environment and enterprises including size, ownership structure, and health and safety management.