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Conventional analyses suggest that the metabolism of heterotrophs is thermally more sensitive than that of autotrophs, implying that warming leads to pronounced trophodynamic imbalances. However, these analyses inappropriately combine within-and acrosstaxa trends. Our new analysis separates these, revealing that 92% of the difference in the apparent thermal sensitivity between autotrophic and heterotrophic protists does indeed arise from within-taxa responses. Fitness differences among taxa adapted to different temperature regimes only partially compensate for the positive biochemical relationship between temperature and growth rate within taxa, supporting the hotter-is-partially-better hypothesis. Our work highlights the importance of separating within-and across-taxa responses when comparing temperature sensitivities between groups, which is relevant to how trophic imbalances and carbon fluxes respond to warming.

Recent advances in molecular technology have revolutionized research on all aspects of the biology of organisms, including ciliates, and created unprecedented opportunities for pursuing a more integrative approach to investigations of biodiversity. However, this goal is complicated by large gaps and inconsistencies that still exist in the foundation of basic information about biodiversity of ciliates. The present paper reviews issues relating to the taxonomy of ciliates and presents specific recommendations for best practice in the observation and documentation of their biodiversity. This effort stems from a workshop that explored ways to implement six Grand Challenges proposed by the International Research Coordination Network for Biodiversity of Ciliates (IRCN-BC). As part of its commitment to strengthening the knowledge base that supports research on biodiversity of ciliates, the IRCN-BC proposes to populate The Ciliate Guide, an online database, with biodiversity-related data and metadata to create a resource that will facilitate accurate taxonomic identifications and promote sharing of data., U.S. National Science Foundation, National Natural Science Foundation of China, Depto. de Genética, Fisiología y Microbiología, Fac. de Ciencias Biológicas, TRUE, pub

The Penman–Monteith equation has been widely used to estimate the maximum evaporation rate (E) from wet/saturated forest canopies, regardless of canopy cover fraction. Forests are then represented as a big leaf and interception loss considered essentially as a one-dimensional process. With increasing forest sparseness the assumptions behind this big leaf approach become questionable. In sparse forests it might be better to model E and interception loss at the tree level assuming that the individual tree crowns behave as wet bulbs (‘‘wet bulb approach”). In this study, and for five different forest types and climate conditions, interception loss measurements were compared to modelled values (Gash’s interception model) based on estimates of E by the Penman–Monteith and the wet bulb approaches. Results show that the wet bulb approach is a good, and less data demanding, alternative to estimate E when the forest canopy is fully ventilated (very sparse forests with a narrow canopy depth). When the canopy is not fully ventilated, the wet bulb approach requires a reduction of leaf area index to the upper, more ventilated parts of the canopy, needing data on the vertical leaf area distribution, which is seldom-available. In such cases, the Penman–Monteith approach seems preferable. Our data also show that canopy cover does not per se allow us to identify if a forest canopy is fully ventilated or not. New methodologies of sensitivity analyses applied to Gash’s model showed that a correct estimate of E is critical for the proper modelling of interception loss.

The Penman–Monteith equation has been widely used to estimate the maximum evaporation rate (E) from wet/saturated forest canopies, regardless of canopy cover fraction. Forests are then represented as a big leaf and interception loss considered essentially as a one-dimensional process. With increasing forest sparseness the assumptions behind this big leaf approach become questionable. In sparse forests it might be better to model E and interception loss at the tree level assuming that the individual tree crowns behave as wet bulbs (‘‘wet bulb approach”). In this study, and for five different forest types and climate conditions, interception loss measurements were compared to modelled values (Gash’s interception model) based on estimates of E by the Penman–Monteith and the wet bulb approaches. Results show that the wet bulb approach is a good, and less data demanding, alternative to estimate E when the forest canopy is fully ventilated (very sparse forests with a narrow canopy depth). When the canopy is not fully ventilated, the wet bulb approach requires a reduction of leaf area index to the upper, more ventilated parts of the canopy, needing data on the vertical leaf area distribution, which is seldom-available. In such cases, the Penman–Monteith approach seems preferable. Our data also show that canopy cover does not per se allow us to identify if a forest canopy is fully ventilated or not. New methodologies of sensitivity analyses applied to Gash’s model showed that a correct estimate of E is critical for the proper modelling of interception loss.

Functional ecology is a subdiscipline that aims to enable a mechanistic understanding of patterns and processes from the organismic to the ecosystem level. This paper addresses some main aspects of the process-oriented current knowledge on phagotrophic, i.e. heterotrophic and mixotrophic, protists in aquatic food webs. This is not an exhaustive review; rather, we focus on conceptual issues, in particular on the numerical and functional response of these organisms. We discuss the evolution of concepts and define parameters to evaluate predator–prey dynamics ranging from Lotka–Volterra to the Independent Response Model. Since protists have extremely versatile feeding modes, we explore if there are systematic differences related to their taxonomic affiliation and life strategies. We differentiate between intrinsic factors (nutritional history, acclimatisation) and extrinsic factors (temperature, food, turbulence) affecting feeding, growth, and survival of protist populations. We briefly consider intraspecific variability of some key parameters and constraints inherent in laboratory microcosm experiments. We then upscale the significance of phagotrophic protists in food webs to the ocean level. Finally, we discuss limitations of the mechanistic understanding of protist functional ecology resulting from principal unpredictability of nonlinear dynamics. We conclude by defining open questions and identifying perspectives for future research on functional ecology of aquatic phagotrophic protists

Since ciliates rarely possess structures that easily fossilize, we are limited in our ability to use paleontological studies to reconstruct the early evolution of this large and ecologically important clade of protists. Tintinnids, a group of loricate (house-forming) planktonic ciliates, are the only group that has a significant fossil record. Putative tintinnid fossils from rocks older than Jurassic, however, possess few to no characters that can be found in extant ciliates; these fossils are best described as ‘incertae sedis eukaryotes’. Here, we review the Devonian fossil Nassacysta reticulata and propose that it is likewise another incertae sedis eukaryote due to the lack of any unambiguous ciliate characters. Future tintinnid fossil descriptions would be most helpful if: (i) neutral terminology is used in the descriptions but ciliate-specific terminology in the interpretations; (ii) the current ciliate classification is used, although fossil data may expand or modify classifications based on modern forms; (iii) close collaboration with specialists studying extant ciliates is done; and (iv) editors include an expert of extant ciliates in the review process., Deutsche Forschungsgemeinschaft, National Science Foundation, Depto. de Genética, Fisiología y Microbiología, Fac. de Ciencias Biológicas, TRUE, pub

In seasonally dry climates, such as the Mediterranean, lack of rainfall in the usually wet winter may originate severe droughts which are a main cause of inter-annual variation in carbon sequestration. Leaf phenology variability may alter the seasonal pattern of photosynthetic uptake, which in turn is determined by leaf gas exchange limitations. The current study is based on the monitoring of an extremely dry winter in an evergreen cork oak woodland under the Mediterranean climate of central Portugal. Results are focused on net ecosystem CO2 exchange (NEE), phenology and tree growth measurements during two contrasting years: 2011, a wet year with a typical summer drought pattern and 2012, with an extremely unusual dry winter (only 10 mm of total rainfall) that exacerbated the following summer drought effects. Main aims of this study were to assess the effects of an extreme dry winter in (1) annual and seasonal net ecosystem CO2 exchange, and in (2) cork oak phenology. The dry year 2012 was marked by a 45% lower carbon sequestration (−214 vs. −388 g C m−2 year−1) and a 63% lower annual tree diameter growth but only a 9% lower leaf area index compared to the wet year 2011. A significant reduction of 15% in yearly carbon sequestration was associated with leaf phenological events of canopy renewal in the early spring. In contrast to male flower production, fruit setting was severely depressed by water stress with a 54% decrease during the dry year. Our results suggest that leaf growth and leaf area maintenance are resilient ecophysiological processes under winter drought and are a priority carbon sink for photoassimilates in contrast to tree diameter growth. Thus, carbon sequestration reductions under low water availabilities in cork oak woodland should be ascribed to stomatal regulation or photosynthetic limitations and to a lesser extent to leaf area reductions.

The Osisko open-pit Au mine in Quebec, Canada, produces low-grade ore at 55 000 t/day and the non-acid generating wastes will eventually cover large surfaces that will need to be reclaimed. Milling wastes will be deposited as thickened tailings to minimise water consumption. Two studies were carried out, the first involving the establishment of plantations on compacted waste rock covered with overburden topsoil or subsoil at two compaction intensities and the second in a glass house to evaluate the capacity of the thickened tailings to sustain the growth of tamarack, jack pine, black spruce, basket willow, hybrid poplars and green alder. Tailings alone or mixed with amendments including overburden soils, vermicomposts from food wastes, chicken manure and peat were tested, and the use of a thin or thick layer of overburden topsoil was also investigated. The results showed that direct planting in the thickened tailings was not suitable for boreal trees, probably due to the high water retention capacity and low macroporosity of the substrate which limited O2 availability required for root respiration. An organic matter-rich amendment increased the macroporosity to levels suitable for tree growth, with peat being the most effective amendment. Composts produced appropriate porosity levels but also increased electrical conductivity to levels which limited broad-leaved species survival and conifer biomass production. No trace metal contamination of the trees occurred in the mixtures, and the presence of underlying alkaline tailings limited Mn, Zn and Al phytotoxicity of the acidic overburden topsoil layer from occurring in tree leaves. Growth was improved with a thin layer compared with a thick layer of overburden soil, although the trees showed Cu accumulation in the fine roots., The Osisko open-pit Au mine in Quebec, Canada, produces low-grade ore at 55 000 t/day and the non-acid generating wastes will eventually cover large surfaces that will need to be reclaimed. Milling wastes will be deposited as thickened tailings to minimise water consumption. Two studies were carried out, the first involving the establishment of plantations on compacted waste rock covered with overburden topsoil or subsoil at two compaction intensities and the second in a glass house to evaluate the capacity of the thickened tailings to sustain the growth of tamarack, jack pine, black spruce, basket willow, hybrid poplars and green alder. Tailings alone or mixed with amendments including overburden soils, vermicomposts from food wastes, chicken manure and peat were tested, and the use of a thin or thick layer of overburden topsoil was also investigated. The results showed that direct planting in the thickened tailings was not suitable for boreal trees, probably due to the high water retention capacity and low macroporosity of the substrate which limited O2 availability required for root respiration. An organic matter-rich amendment increased the macroporosity to levels suitable for tree growth, with peat being the most effective amendment. Composts produced appropriate porosity levels but also increased electrical conductivity to levels which limited broad-leaved species survival and conifer biomass production. No trace metal contamination of the trees occurred in the mixtures, and the presence of underlying alkaline tailings limited Mn, Zn and Al phytotoxicity of the acidic overburden topsoil layer from occurring in tree leaves. Growth was improved with a thin layer compared with a thick layer of overburden soil, although the trees showed Cu accumulation in the fine roots.

Knowing the distribution of marine animals is central to understanding climatic and other environmental influences on population ecology. This information has proven difficult to gain through capture-based methods biased by capture location. Here we show that marine location can be inferred from animal tissues. As the carbon isotope composition of animal tissues varies with sea surface temperature, marine location can be identified by matching time series of carbon isotopes measured in tissues to sea surface temperature records. Applying this technique to populations of Atlantic salmon (Salmo salar L.) produces isotopically-derived maps of oceanic feeding grounds, consistent with the current understanding of salmon migrations, that additionally reveal geographic segregation in feeding grounds between individual philopatric populations and age-classes. Carbon isotope ratios can be used to identify the location of open ocean feeding grounds for any pelagic animals for which tissue archives and matching records of sea surface temperature are available.

Knowing the distribution of marine animals is central to understanding climatic and other environmental influences on population ecology. This information has proven difficult to gain through capture-based methods biased by capture location. Here we show that marine location can be inferred from animal tissues. As the carbon isotope composition of animal tissues varies with sea surface temperature, marine location can be identified by matching time series of carbon isotopes measured in tissues to sea surface temperature records. Applying this technique to populations of Atlantic salmon (Salmo salar L.) produces isotopically-derived maps of oceanic feeding grounds, consistent with the current understanding of salmon migrations, that additionally reveal geographic segregation in feeding grounds between individual philopatric populations and age-classes. Carbon isotope ratios can be used to identify the location of open ocean feeding grounds for any pelagic animals for which tissue archives and matching records of sea surface temperature are available.

This study focuses on a large region of the open ocean where we predict microzooplankton significantly influence foodweb structure over much of the year. The Irminger Sea exhibits low primary production that is generally poor for copepod production; in such waters ciliates and other microzooplankton can contribute significantly to the diets of holo- and mero- mesozooplankton and are major grazers of primary production. Surface plankton samples were collected during an extensive survey, across the basin and along one transect at several depths, over three seasons (winter, spring, summer), but not including the spring bloom. Microzooplankton and phytoplankton samples were fixed with Lugol’s solution and microscopically enumerated for species abundance; biomass was determined from cell volumes. Basin-scale distributions of abundance, biomass, and production were examined by geostatistical and multidimensional scaling methods. The dominance of the < 10 µm phytoplankton suggests that this should be a microzooplankton-dominated food web. Ciliates and heterotrophic dinoflagellates are abundant, in terms of numbers and biomass; heterotrophic dinoflagellates are more abundant than ciliates, but are less dominant in terms of biomass. Using ciliates as a proxy for all microzooplankton we suggest that there are seasonal patterns in occurrence, and there is no basin-scale patchiness related to hydrographic features. Through some simple, albeit “rough” calculations, we suggest that ciliate production may be sufficient to account for the removal of 15-30% of the < 10 µm primary production. If heterotrophic dinoflagellates were included in these estimates, they may be doubled (i.e. 30-60%). We, thus, contend that microzooplankton are major phytoplankton consumers in the system and should be carefully parameterised in models of this region.

This study focuses on a large region of the open ocean where we predict microzooplankton significantly influence foodweb structure over much of the year. The Irminger Sea exhibits low primary production that is generally poor for copepod production; in such waters ciliates and other microzooplankton can contribute significantly to the diets of holo- and mero- mesozooplankton and are major grazers of primary production. Surface plankton samples were collected during an extensive survey, across the basin and along one transect at several depths, over three seasons (winter, spring, summer), but not including the spring bloom. Microzooplankton and phytoplankton samples were fixed with Lugol’s solution and microscopically enumerated for species abundance; biomass was determined from cell volumes. Basin-scale distributions of abundance, biomass, and production were examined by geostatistical and multidimensional scaling methods. The dominance of the < 10 µm phytoplankton suggests that this should be a microzooplankton-dominated food web. Ciliates and heterotrophic dinoflagellates are abundant, in terms of numbers and biomass; heterotrophic dinoflagellates are more abundant than ciliates, but are less dominant in terms of biomass. Using ciliates as a proxy for all microzooplankton we suggest that there are seasonal patterns in occurrence, and there is no basin-scale patchiness related to hydrographic features. Through some simple, albeit “rough” calculations, we suggest that ciliate production may be sufficient to account for the removal of 15-30% of the < 10 µm primary production. If heterotrophic dinoflagellates were included in these estimates, they may be doubled (i.e. 30-60%). We, thus, contend that microzooplankton are major phytoplankton consumers in the system and should be carefully parameterised in models of this region.

A new approach is suggested for estimating evaporation of intercepted rainfall from single trees in sparse forests. It is shown that, theoretically, the surface temperature of a wet tree crown will depend on the available energy and windspeed. But for a fully saturated canopy under rainy conditions, surface temperature will approach the wet bulb temperature when available energy tends to zero. This was confirmed experimentally from measurements of the radiation balance, aerodynamic conductance for water vapour and surface temperature on an isolated tree crown. Net radiation over a virtual cylindrical surface, enclosing the tree crown, was monitored by a set of radiometers positioned around that surface. Aerodynamic conductance for the tree crown was derived by scaling up measurements of leaf boundary layer conductance using the heated leaf replica method. Thermocouples were used to measure the average leaf surface temperature. Results showed that a fully wet single tree crown behaves like a wet bulb, allowing evaporation of intercepted rainfall to be estimated by a simple diffusion equation for water vapour, which is not restricted by the assumptions of one-dimensional transfer models usually used at the stand scale. Using this approach, mean evaporation rate from wet, saturated tree crowns was 0.27 or 0.30 mm h−1, when surface temperature was taken equal to the air wet bulb temperature or estimated accounting for the available energy, respectively.

In a previous study, it was shown that an isolated, fully saturated tree-crown behaves like a wet bulb, allowing evaporation of intercepted rainfall to be estimated by a simple diffusion equation for water vapour. This observation was taken as the basis for a new approach in modelling interception loss from savanna-type woodland, whereby the ecosystem evaporation is derived by scaling up the evaporation from individual trees, rather than by considering a homogeneous forest cover. Interception loss from isolated trees was estimated by combining the aforementioned equation for water vapour flux with Gash's analytical model. A new methodology, which avoids the subjectivity inherent in the Leyton method, was used for estimating the crown storage capacity. Modelling performance was evaluated against data from two Mediterranean savanna-type oak woodlands (montados) in southern Portugal. Interception loss estimates were in good agreement with observations in both sites. The proposed modelling approach is physically based, requires only a limited amount of data and should be suitable for the modelling of interception loss in isolated trees and savanna-type ecosystems.

A new approach is suggested for estimating evaporation of intercepted rainfall from single trees in sparse forests. It is shown that, theoretically, the surface temperature of a wet tree crown will depend on the available energy and windspeed. But for a fully saturated canopy under rainy conditions, surface temperature will approach the wet bulb temperature when available energy tends to zero. This was confirmed experimentally from measurements of the radiation balance, aerodynamic conductance for water vapour and surface temperature on an isolated tree crown. Net radiation over a virtual cylindrical surface, enclosing the tree crown, was monitored by a set of radiometers positioned around that surface. Aerodynamic conductance for the tree crown was derived by scaling up measurements of leaf boundary layer conductance using the heated leaf replica method. Thermocouples were used to measure the average leaf surface temperature. Results showed that a fully wet single tree crown behaves like a wet bulb, allowing evaporation of intercepted rainfall to be estimated by a simple diffusion equation for water vapour, which is not restricted by the assumptions of one-dimensional transfer models usually used at the stand scale. Using this approach, mean evaporation rate from wet, saturated tree crowns was 0.27 or 0.30 mm h−1, when surface temperature was taken equal to the air wet bulb temperature or estimated accounting for the available energy, respectively.

In a previous study, it was shown that an isolated, fully saturated tree-crown behaves like a wet bulb, allowing evaporation of intercepted rainfall to be estimated by a simple diffusion equation for water vapour. This observation was taken as the basis for a new approach in modelling interception loss from savanna-type woodland, whereby the ecosystem evaporation is derived by scaling up the evaporation from individual trees, rather than by considering a homogeneous forest cover. Interception loss from isolated trees was estimated by combining the aforementioned equation for water vapour flux with Gash's analytical model. A new methodology, which avoids the subjectivity inherent in the Leyton method, was used for estimating the crown storage capacity. Modelling performance was evaluated against data from two Mediterranean savanna-type oak woodlands (montados) in southern Portugal. Interception loss estimates were in good agreement with observations in both sites. The proposed modelling approach is physically based, requires only a limited amount of data and should be suitable for the modelling of interception loss in isolated trees and savanna-type ecosystems.

Myrionecta rubra, a ubiquitous planktonic ciliate, has received much attention due to its wide distribution, occurrence as a red tide organism, and unusual cryptophyte endosymbiont. Although well studied in coastal waters, M. rubra is poorly examined in the open ocean. In the Irminger Basin, North Atlantic, the abundance of M. rubra was 0–5 cells/ml, which is low compared with that found in coastal areas. Distinct patchiness (100 km) was revealed by geostatistical analysis. Multiple regression indicated there was little relationship between M. rubra abundance and a number of environmental factors, with the exception of temperature and phytoplankton biomass, which influenced abundance in the spring. We also improve on studies that indicate distinct size classes of M. rubra; we statistically recognise four significantly distinct width classes (5–16, 12–23, 18–27, 21–33 μm), which decrease in abundance with increasing size. A multinomial logistic regression revealed the main variable correlated with this size distribution was ambient nitrate concentration. Finally, we propose a hypothesis for the distribution of sizes, involving nutrients, feeding, and dividing of the endosymbiont.

The marine, tide pool-dwelling ciliate Stombidium oculatum was redescribed using live, stained, SEM, and TEM material prepared from samples collected from pools on the Isle of Man (Irish Sea) and Brittany (France). Also, we reviewed the older German and French works that reported on ciliates collected in the Mediterranean and Brittany, respectively. The Brittany and Isle of Man populations of the ciliate were considered identical. Some morphological and behavioural differences exist between the Brittany-Isle of Man populations and the Mediterranean populations, but they were insufficient to distinguish different taxa. Thus, taxa from all three locations were considered to be conspecific. Key features used to describe the ciliate were+morphology and ultrastructure of the free-swimming ciliate; cyst morphology; presence of mixotrophic-chloroplasts; presence of an eye spot composed of stigma obtained from chlorophyte prey; division, morphogenesis, and nuclear structure; live observations and behaviour, including the encystment-excystment cycle. Based on morphological and behavioural characteristics the taxon was distinguished from other similar species, and a neotype has been designated as no type material exists.

The marine, tide pool-dwelling ciliate Stombidium oculatum was redescribed using live, stained, SEM, and TEM material prepared from samples collected from pools on the Isle of Man (Irish Sea) and Brittany (France). Also, we reviewed the older German and French works that reported on ciliates collected in the Mediterranean and Brittany, respectively. The Brittany and Isle of Man populations of the ciliate were considered identical. Some morphological and behavioural differences exist between the Brittany-Isle of Man populations and the Mediterranean populations, but they were insufficient to distinguish different taxa. Thus, taxa from all three locations were considered to be conspecific. Key features used to describe the ciliate were+morphology and ultrastructure of the free-swimming ciliate; cyst morphology; presence of mixotrophic-chloroplasts; presence of an eye spot composed of stigma obtained from chlorophyte prey; division, morphogenesis, and nuclear structure; live observations and behaviour, including the encystment-excystment cycle. Based on morphological and behavioural characteristics the taxon was distinguished from other similar species, and a neotype has been designated as no type material exists.