Distribution, Population Biology, and Trophic Ecology of the Deepwater Demersal Fish Halosauropsis macrochir (Pisces: Halosauridae) on the Mid-Atlantic Ridge

Halosauropsis macrochir ranked amongst the most abundant and widespread demersal fishes on the mid-Atlantic Ridge of the North Atlantic (Iceland-Azores) with greatest abundance at 1700–3500 m. All sizes, ranging from 10–76 cm total length, occurred in the area without any apparent spatial pattern or depth trend. Using otolith sections displaying growth increments assumed to represent annuli, the age range recorded was 2–36 years, but most individuals were <20 years. Length and weight at age data were used to fit growth models. No differences between sexes in length and weight at age were observed. The majority of samples had a surplus of males. Diet analysis showed that H. macrochir feeds on Crustacea, Teleostei, Polychaeta, and Cephalopoda, but few prey could be identified to lower taxonomical levels. The mid-Atlantic Ridge constitutes a major portion of the North Atlantic living space of the abyssal halosaur where it completes its full life cycle, primarily as an actively foraging euryophagous micronekton/epibenthos and infauna feeder, becoming a partial piscivore with increasing size

Evaluating model outputs using integrated global speleothem records of climate change since the last glacial

Although quantitative isotope data from speleothems has been used to evaluate isotope-enabled model simulations, currently no consensus exists regarding the most appropriate methodology through which to achieve this. A number of modelling groups will be running isotope-enabled palaeoclimate simulations in the framework of the Coupled Model Intercomparison Project Phase 6, so it is timely to evaluate different approaches to using the speleothem data for data–model comparisons. Here, we illustrate this using 456 globally distributed speleothem δ18O records from an updated version of the Speleothem Isotopes Synthesis and Analysis (SISAL) database and palaeoclimate simulations generated using the ECHAM5-wiso isotope-enabled atmospheric circulation model. We show that the SISAL records reproduce the first-order spatial patterns of isotopic variability in the modern day, strongly supporting the application of this dataset for evaluating model-derived isotope variability into the past. However, the discontinuous nature of many speleothem records complicates the process of procuring large numbers of records if data–model comparisons are made using the traditional approach of comparing anomalies between a control period and a given palaeoclimate experiment. To circumvent this issue, we illustrate techniques through which the absolute isotope values during any time period could be used for model evaluation. Specifically, we show that speleothem isotope records allow an assessment of a model's ability to simulate spatial isotopic trends. Our analyses provide a protocol for using speleothem isotope data for model evaluation, including screening the observations to take into account the impact of speleothem mineralogy on δ18O values, the optimum period for the modern observational baseline and the selection of an appropriate time window for creating means of the isotope data for palaeo-time-slices

Population ecology of the sea lamprey (Petromyzon marinus) as an invasive species in the Laurentian Great Lakes and an imperiled species in Europe

The sea lamprey Petromyzon marinus (Linnaeus) is both an invasive non-native species in the Laurentian Great Lakes of North America and an imperiled species in much of its native range in North America and Europe. To compare and contrast how understanding of population ecology is useful for control programs in the Great Lakes and restoration programs in Europe, we review current understanding of the population ecology of the sea lamprey in its native and introduced range. Some attributes of sea lamprey population ecology are particularly useful for both control programs in the Great Lakes and restoration programs in the native range. First, traps within fish ladders are beneficial for removing sea lampreys in Great Lakes streams and passing sea lampreys in the native range. Second, attractants and repellants are suitable for luring sea lampreys into traps for control in the Great Lakes and guiding sea lamprey passage for conservation in the native range. Third, assessment methods used for targeting sea lamprey control in the Great Lakes are useful for targeting habitat protection in the native range. Last, assessment methods used to quantify numbers of all life stages of sea lampreys would be appropriate for measuring success of control in the Great Lakes and success of conservation in the native range

Effects of wildfire on long-term soil CO₂ concentration: Implications for karst processes

Fire reduces soil CO₂ concentration by destroying vegetation and soil dwelling microbial communities thus reducing both heterotrophic and autotrophic contributions to soil respiration. While reductions in microbial respiration are short-lived, root respiration can take longer to recover, depending on the dominant growth forms (e.g. trees vs herbs) and modes of post-fire recovery (e.g. resprouting vs seedling establishment). This study aimed to quantify whether soil CO₂ concentration was reduced ~5 years and ~10 years after a fire in a subalpine karst environment in south-eastern Australia and to consider the implications for karst dissolution processes and speleothem growth rate. Paired sites with burnt and unburnt soil were compared with regards to CO₂ concentrations, soil moisture and porosity. Samples were taken from a grassland site and woodland site burnt ~5 years ago and a woodland site burnt ~10 years ago. The results showed that soil respiration was depressed in burnt sites relative to the unburnt pair in both the grassland and woodland sites after ~5 years; however, after ~10 years there was no significant difference between the burnt and control woodland sites. This indicates that soil CO₂ concentration takes between 5-10 years to return to pre-fire levels in subalpine environments in south-eastern Australia. In a karst environment, this long-term reduction in soil CO₂ concentration caused by fire is likely to cause a decreased stalagmite growth that could be incorrectly attributed to multiannual climatic drying, such as the El Nino Southern Oscillation, when reconstructing past environmental change from stalagmite records

Methods and Instruments for the Estimation of Production Changes in Economic Evaluations

This chapter focuses on the indirect costs of paid work that result from mental illness. It provides an overview of monetary valuation methods and approaches to measure and value production gains and losses. The methods are applied to mental illness, although they have also been applied to other diseases. As mental health and mental health care can have different effects on production, the chapter starts by explaining how to classify the consequences of mental illness for the production of firms. It follows with the definitions of different types of production. This chapter subsequently presents and discusses three major approaches to value production. It pays attention to the human capital approach, the friction costs approach, and the multiplier approach. The chapter ends with a description of survey questions and instruments to measure and value production changes in economic evaluations