Trophic Characteristics Research Articles

Trophic Status of the Dniester Delta Lakes in 2006-2017

Purpose. Assessment of trophic status of the Dniester deltaic part lakes (Bile, Svine, Tudorovo and Putrino) in 2006-2017. Methods. Determination of hydrological, hydrochemical and hydrobiological characteristics of the lakes aquatic environment has been performed using standard methodologies. Three indicators of eutrophication have been used: chlorophyll a concentration, number of bacterioplankton, trophic indices TSI and TRIX. Results. Peculiarities of physicochemical characteristics of water in the Dniester deltaic lakes have been analysed. Increased nutrients concentration has been revealed in all the lakes during past 12 years. The lowest oxygen content and oxygen saturation was established in water of the Putrino Lake, where at the same time the highest concentrations of total nitrogen and phosphorus were observed. Analysis of long-term changes of chlorophyll a and bacterioplankton has been done. Based on the lakes integrated study in summer time of 2006-2017, assessment of water trophic state has been for the first time performed for each deltaic lake. Statistical interrelations between trophic state indicators and physicochemical characteristics of the lakes have been revealed. Conclusions. It was established that the assessment of four deltaic lakes trophic status based on chlorophyll a, bacterioplankton and TSI trophic index practically coincided and evidenced increased of the lakes’ trophic status and decrease of water quality in 2012-2017 compared with previous years. All the eutrophication indicators in water of the lakes Svine, Tudorovo and Putrino during six last years corresponded to hypertrophic status, while in the Bile Lake most of eutrophication indicators were lower and corresponded to eutrophic status. Trophic index TRIX, which was developed for seawater assessment, practically always showed somewhat higher trophic status of the lakes than other indicators.

Study of Changes of Trophic Status of the Kuchurganske Reservoir in 2006-2018

Purpose. Assessment of the trophic status of water in the Kuchurganske Reservoir in 2006-2018. Methods. Determination of hydrological, hydrochemical and hydrobiological characteristics of the water body's environment has been done using standard methodologies. Four indicators of water eutrophication have been used: chlorophyll a concentration, bacterioplankton number, trophic indices TSI and TRIX. Results. Features of physicochemical characteristics of water in the water-body have been analysed. Higher water temperature has been registered in the middle and lower parts of the water-body compared with its upper reaches. Mineral content increase in water has been found in the direction from lower to upper part; the critical for hydrobionts life decrease of oxygen concentration has been registered in the upper reaches the most often. Analysis of long-term changes in chlorophyll a and bacterioplankton has been carried out. Statistical interconnections have been established between trophic state indicators and physicochemical characteristics of the reservoir. A close positive correlation has been registered between chlorophyll а content and bacterioplankton number, which is caused by the functional dependence of bacteria on the organic matter produced by phytoplankton. It has been shown that with an increase of water volume in the reservoir the value of these indicators of trophic status went down, which was proved by close negative correlation dependence between those values and the depth of water-body. It was demonstrated for the first time that water transparency revealed close significant negative correlation with all the indices and indicators of water trophic status, which evidenced the possibility to use the transparency as a simple indicator of water trophic state as established that the Kuchurganske Reservoir’s trophic status assessment on chlorophyll a, bacterioplankton and the TSI trophic index practically coincided and evidenced the increase in trophic status of the water-body from eutrophic to hypertrophic in last 2016-2018. The reservoir’s upper reaches were characterized by higher water trophicity compared with the central and lower parts. The values of TRIX trophic index developed for marine water assessment had practically always been showing higher trophic status compared to other indicators.

Bacterial Community in Water and Air of Two Sub-Alpine Lakes in Taiwan.

Very few studies have attempted to profile the microbial communities in the air above freshwater bodies, such as lakes, even though freshwater sources are an important part of aquatic ecosystems and airborne bacteria are the most dispersible microorganisms on earth. In the present study, we investigated microbial communities in the waters of two high mountain sub-alpine montane lakes—located 21 km apart and with disparate trophic characteristics—and the air above them. Although bacteria in the lakes had locational differences, their community compositions remained constant over time. However, airborne bacterial communities were diverse and displayed spatial and temporal variance. Proteobacteria, Actinobacteria, Bacteroidetes, and Cyanobacteria were dominant in both lakes, with different relative abundances between lakes, and Parcubacteria (OD1) was dominant in air samples for all sampling times, except two. We also identified certain shared taxa between lake water and the air above it. The results obtained on these communities in the present study provide putative candidates to study how airborne communities shape lake water bacterial compositions and vice versa.

Variations in the Carbon and Nitrogen Isotope Composition of the Crabs Chionoecetes opilio (Fabricius, 1788) and Hyas coarctatus Leach, 1816 (Crustacea: Decapoda) from the Chukchi Sea

Some regions of the Chukchi Sea shelf are characterized by an unusually high abundance of the benthos. The carbon and nitrogen isotope composition (δ13C and δ15N) of two crab species, Chionoecetes opilio and Hyas coarctatus, which occupy the upper trophic levels in bottom communities in the southern regions influenced by the Anadyr Water (AW) and in the regions exposed to the influence of the Siberian Coastal Current (SCC), was analyzed in order to compare between the trophic characteristics of their benthic communities. It has been found that these two species have similar spatial trends of stable isotope signature variations. As the effect of the productive AW on bottom communities decreases, a substantial depletion of δ13C with a simultaneous growth of δ15N values are observed in crab tissues. The trophic niches of C. opilio and H. coarctatus, which are represented by “isotope” niches as standard ellipse areas in the δ13C/δ15N biplot, significantly overlap in communities of the southern part of the shelf and become completely separated in those of the regions influenced by the SCC. The separation of the isotope niches of C. opilio and H. coarctatus and the simultaneous increase in δ15N values in both species by more than 3‰ indicate partitioning of the trophic resources between them and elongation of the food chains of both these carnivorous generalists by almost one trophic level in the communities that exist under the influence of less productive waters.

Oligotrophy as a major driver of mercury bioaccumulation in medium-to high-trophic level consumers: A marine ecosystem-comparative study.

Mercury (Hg) is a global contaminant of environmental concern. Numerous factors influencing its bioaccumulation in marine organisms have already been described at both individual and species levels (e.g., size or age, habitat, trophic level). However, few studies have compared the trophic characteristics of ecosystems to explain underlying mechanisms of differences in Hg bioaccumulation and biomagnification among food webs and systems. The present study aimed at investigating the potential primary role of the trophic status of systems on Hg bioaccumulation and biomagnification in temperate marine food webs, as shown by their medium-to high-trophic level consumers. It used data from samples collected at the shelf-edge (i.e. offshore organisms) in two contrasted ecosystems: the Bay of Biscay in the North-East Atlantic Ocean and the Gulf of Lion in the North-West Mediterranean Sea. Seven species including crustaceans, sharks and teleost fish, previously analysed for their total mercury (T-Hg) concentrations and their stable carbon and nitrogen isotope compositions, were considered for a meta-analysis. In addition, methylated mercury forms (or methyl-mercury, Me-Hg) were analysed. Mediterranean organisms presented systematically lower sizes than Atlantic ones, and lower δ13C and δ15N values, the latter values especially highlighting the more oligotrophic character of Mediterranean waters. Mediterranean individuals also showed significantly higher T-Hg and Me-Hg concentrations. Conversely, Me-Hg/T-Hg ratios were higher than 85% for all species, and quite similar between systems. Finally, the biomagnification power of Hg was different between systems when considering T-Hg, but not when considering Me-Hg, and was not different between the Hg forms within a given system. Overall, the different parameters showed the crucial role of the low primary productivity and its effects rippling through the compared ecosystems in the higher Hg bioaccumulation seen in organisms from oligotrophic Mediterranean waters.

Ecologo-faunistic review of lamellicorn beetles (Coleoptera, Scarabaeoidea) of urbocenosis of Kharkov city (Ukraine)

This article presents a general overview of the superfamily Scarabaeoidea in five parks of Kharkov city and some adjacent agrocenosises. The species composition includes 32 species from four families of Scarabaeoidea. The Scarabaeidae family dominated in biodiversity and abundance (26 species from 16 genera). Six species (Dorcus parallelopipedus, Platyderes caraboides, Anoplotrupes stercorosus, Aphodius melanostictus, Pleurophorus caesus and Onthophagus coenobita) were sporadically registered as common, but in separate urban cenosises the number of species did not exceed one or three. The species composition and abundance of lamellicorn beetles was higher in large parks with only slight recreational disturbance. Here from 13 to 20 species were registered. On lawns in the center and in other districts of the city Scarabaeoidea species met very rarely. In the agrocenosises on the outskirts of Kharkov city – 16 species are noted, almost half of which were registered as common. The faunistic similarity of different urban cenosises was at low to medium levels (an average 0.20–0.47). These indices were slightly higher (0.38–0.67) for areas with lower recreational pressure. The indices of faunal similarity of separate parks and agrocenoses were lower (0.18–0.56, but on average – 0.33). At the level of common species, there was no faunistic similarity. The significance of such differences was due to both the low number of most Lamellicorn species and some of their ecological characteristics. The main differences were observed in the ratio of trophic groups and features of the spatial distribution of the dominant species. Smaller differences were observed on biotopic characteristic of most species. There were no differences in the hygropreference of the scarabeid species. In the parks herpetobiont saprophagous species dominated (mainly coprophagous and dendrophagous). In the agrocenoses, dendrochordobiontic phytophagous species predominated. The peculiarities of the ratio of different ecological groups of Scarabaeoidea in urban and agrocenosises are discussed.

Functional redundancy modifies species-area relationship for freshwater phytoplankton.

Although species–area relationship (SAR) is among the most extensively studied patterns in ecology, studies on aquatic and/or microbial systems are seriously underrepresented in the literature. We tested the algal SAR in lakes, pools and ponds of various sizes (10−2–108 m2) and similar hydromorphological and trophic characteristics using species‐specific data and functional groups. Besides the expectation that species richness increases monotonously with area, we found a right‐skewed hump‐shaped relationship between the area and phytoplankton species richness. Functional richness however did not show such distortion. Differences between the area dependence of species and functional richness indicate that functional redundancy is responsible for the unusual hump‐backed SAR. We demonstrated that the Small Island Effect, which is a characteristic for macroscopic SARs can also be observed for the phytoplankton. Our results imply a so‐called large lake effect, which means that in case of large lakes, wind‐induced mixing acts strongly against the habitat diversity and development of phytoplankton patchiness and finally results in lower phytoplankton species richness in the pelagial. High functional redundancy of the groups that prefer small‐scale heterogeneity of the habitats is responsible for the unusual humpback relationship. The results lead us to conclude that although the mechanisms that regulate the richness of both microbial communities and communities of macroscopic organisms are similar, their importance can be different in micro‐ and macroscales.

Shifts of radiocesium vertical profiles in sediments and their modelling in Japanese lakes

Vertical profiles of radiocesium concentrations were measured in sediment cores collected at various times after the 2011 Fukushima nuclear accident in five Japanese lakes (Hinuma, Kasumigaura, Kitaura, Onogawa and Sohara) with different morphological and trophic characteristics in order to investigate the sedimentation-diffusion processes. In lakes where sediments had high porosities and experienced considerable wave action due to shallowness, we observed rapid penetration of radiocesium to a certain depth just after the accident, followed by downward movement of the peak depths. In contrast, gradual downward transfers of distinct peaks were found in other types of lakes. A one-dimensional differential sediment model with water-sediments interaction processes was constructed to describe the vertical shift of radiocesium profiles. Our proposed submodels relating to the length scales of the mixing using wind-induced stress and porosity of sediments were constructed based on one measurement of the vertical distribution of radiocesium in three lakes (Hinuma, Kasumigaura and Sohara). This model was then validated using samples from those lakes in different years, as well as from two other lakes. Good agreement was obtained. We discuss our findings, the limits of model application, and future research targets.

Dieta y reproducción de Bryconamericus caucanus (Characiformes: Characidae) en la Quebrada La Venada, Río Quindío, Colombia

Objetivo. Se analizó la ecología trófica y reproductiva de Bryconamericus caucanus en la quebrada la Venada, Rio Quindío, Alto Cauca, Colombia. Materiales y métodos. Los ejemplares se recolectaron entre enero y diciembre del 2013. Se realizaron análisis multivariados para comparar las características tróficas entre épocas climáticas (bajas y altas lluvias), sexos y estados de madurez (juveniles y adultos). Se analizó también el factor de condición (K), porcentajes numéricos (%N), volumétricos (%V) y frecuencia de ocurrencia (%Fo) para cada presa. La proporción de sexos se evaluó usando pruebas de Chi-Cuadrado y se estimaron los indices gonadosomático (IGS) y de fecundidad absoluta (Fa). Resultados. Se analizó un total de 162 ejemplares (LS: 40-75 mm). Se encontró que B. caucanus es un pez insectívoro (86.47% IRI), con un consumo preponderante de ephemeropteros (Baetidae; 27.71%), hymenopteros (Formicidae; 23.57%), dipteros (Simuliidae 17.36%; Chironomidae 9.79%) y trichopteros (Hydropsychidae; 8.04). Los analisis multivariados revelaron diferencias tróficas entre épocas climáticas, con menor riqueza durante la época de sequía. Entre sexos, las hembras registran una mayor amplitud del nicho trófico. Los adultos, presentan una amplitud de nicho mayor a juveniles. La especie tiene dos eventos reproductivos en los periodos de altas lluvias relacionados con el incremento en la riqueza trófica durante las mismas épocas (i.e. marzo-abril, septiembre-noviembre). Conclusiones. B. caucanus presenta una segregación trófica incipiente entre estadios ontogénicos y sexos. La distinción trófica es sin embargo notable entre periodos climáticos. Los periodos de desove para B. caucanus ocurren a inicio de los periodos de lluvias (i.e. mayo-junio y septiembre-octubre).

Thermal tolerance and recovery behaviour of Thorectes lusitanicus (Coleoptera, Geotrupidae)

1. Population differences in physiological responses are examined in Thorectes lusitanicus, an endemic Iberian dung beetle species, by submitting individuals of different populations to the same experimental and acclimation conditions.2. An infrared thermography protocol was used, consisting of three assays: start of activity, cold response, and heat response. Individuals of 12 populations were studied and the comparative explanatory capacities of several environmental factors in relation to the observed inter‐population differences were examined.3. The heating rate from chill coma to the beginning of activity was the variable with the highest discrimination power among the studied populations, accounting for 94% of the observed variance. Regarding the heat response, only six of the 16 thermal variables reached significance (inter‐population differences accounted for 52–74% in these six thermal parameters).4. From the three considered environmental factors (Mediterranean climate, land cover, and trophic characteristics) only land cover characteristics remain statistically significant, affecting the cold response of individuals.5. Thorectes lusitanicus is a species characterised by a high diversity of thermotolerance and recovery traits across populations with a low degree of association with broad environmental factors. Finally, it is suggested that the apterous character of this species could be a determinant factor explaining the high diversity of ecophysiological traits related to thermal stress tolerance and the recovery time.

Food Web Interactions Associated With a Lahontan Cutthroat Trout Reintroduction Effort in an Alpine Lake

Abstract Fisheries managers have stocked Lahontan Cutthroat Trout Oncorhynchus clarkii henshawi into Fallen Leaf Lake, California, since 2002 in an attempt to reestablish a naturally reproducing lacustrine population. However, the food web in Fallen Leaf Lake has been altered by the past introduction of nonnative species that may prey on or compete with reintroduced Lahontan Cutthroat Trout. Therefore, we used a combination of stomach content and stable isotope analyses to evaluate trophic characteristics within the aquatic species assemblage in Fallen Leaf Lake. Lahontan Cutthroat Trout preyed on mysid shrimp Mysis diluviana, aquatic insects, terrestrial arthropods, signal crayfish Pacificus leniusculus, and fishes. Diet overlap was greatest between Lahontan Cutthroat Trout and Mountain Whitefish Prosopium williamsoni; however, these species exhibited a generalized feeding strategy that may allow them to partition prey resources in order to avoid competitive interactions. Nonnative Lake Trout Salvelinus namaycush and Brown Trout Salmo trutta are top-level predators in Fallen Leaf Lake and both consumed Lahontan Cutthroat Trout during this study. Lake Trout δ13C and δ15N increased following Lahontan Cutthroat Trout stocking, a change consistent with incorporating isotopically enriched Lahontan Cutthroat Trout into their diet. Managers should consider the effects of predation by Lake Trout and Brown Trout on Lahontan Cutthroat Trout when developing future management and stocking programs for Fallen Leaf Lake. Additionally, intentional manipulation of the isotopic composition of hatchery-reared fish prior to stocking may be useful for evaluating predation in Fallen Leaf Lake and other systems.

Small and shallow previously unstudied lakes: land-use, overgrowth and eutrophication

PurposeThe purpose of this paper is to compare trophic characteristics of the ecosystems of small and shallow lakes with a different character of land-cover in their catchments (as exemplified by several previously unstudied lakes of the Leningrad Region, North-Western Russia, that belong to a single lake-river system).Design/methodology/approachThe key limnetic parameters of four lakes are analysed. Two of the lakes are located on the territory of allotment gardens, the other two are in the forest-covered areas. A preliminary assessment was made for the production-to-destruction ratio in the ecosystems of the lakes of the study region and their vulnerability factors.FindingsFor the lakes with a largely unexploited catchment, humus of terrigenous origin can act as a “hidden” source of nutrient load (primarily as phosphates). For the lakes with a catchment occupied by allotment gardens, an elevated trophic status and intensive overgrowth by vegetation (floating forms) is driven by an increased nitrogen load.Practical implicationsThe results can be used for planning land and water management activities in North-Western Russia and in other world’s regions with similar environmental conditions.Originality/valueThese results can lay a foundation for creating a region-specific model to predict trends in eutrophication and overgrowth of small shallow lakes.

ОСОБЕННОСТИ СОЗДАНИЯ ТОЛЕРАНТНЫХ К ГЛИФОСАТУ ФОРМ САХАРНОЙ СВЕКЛЫ

ОСОБЕННОСТИ СОЗДАНИЯ ТОЛЕРАНТНЫХ К ГЛИФОСАТУ ФОРМ САХАРНОЙ СВЕКЛЫ

Effect of agricultural landscape characteristics on the\xa0hydrobiota structure in small water bodies

Understanding the influence of environmental factors on the hydrobiota structure of small aquatic ecosystems is essential for effective landscape management. In this study of 165 small water bodies situated in the lowland high-productive agricultural landscape of western Poland we evaluate the effect of catchment, buffer zone, water body and water quality parameters on macrophyte functional groups (nymphaeids, elodeids, pleustophytes, helophytes) and zooplankton diversity. The potential pressure of the catchment on ponds was high (mean Ohle index 140). For macrophytes, shore length and depth of pond were highly significant and, subsequently the type of catchment and buffer, while for zooplankton, apart from water depth, trophic features of the habitat were decisive. Cluster analysis was used to identify functional types of water bodies on the basis of catchment and buffer zone attributes. Regardless of physico-geographical macroregion, water bodies of arable catchments with herbage buffer prevailed in a landscape. For protection and prevention of ecological deterioration of ponds and stability of trophic conditions the optimal situation is a buffer which is created by shrubs and trees around the pond.

Persistent Organic Pollutants in albacore tuna (Thunnus alalunga) from Reunion Island (Southwest Indian Ocean) and South Africa in relation to biological and trophic characteristics

The contamination of albacore tuna (Thunnus alalunga) by Persistent Organic Pollutants (POPs), namely polychlorinated biphenyls (PCBs) and dichlorodiphenyl-trichloroethane (DDT), was investigated in individuals collected from Reunion Island (RI) and South Africa's (SA) southern coastlines in 2013, in relation to biological parameters and feeding ecology. The results showed lower PCB and DDT concentrations than those previously reported in various tuna species worldwide. A predominance of DDTs over PCBs was revealed, reflecting continuing inputs of DDT. Tuna collected from SA exhibited higher contamination levels than those from RI, related to higher dietary inputs and higher total lipid content. Greater variability in contamination levels and profiles was identified in tuna from RI, explained by a higher diversity of prey and more individualistic foraging behaviour. PCB and DDT contamination levels and profiles varied significantly in tuna from the two investigated areas, probably reflecting exposure to different sources of contamination.

Modeling landings profiles of fishing vessels: An application of Self-Organizing Maps to VMS and logbook data

Logbook data constitute a key element within the electronic recording and reporting system of the European Fisheries Control Technologies Framework and are used to record, report, process, store and send information about fishing operations, including landings and fishing gear. A relevant application of logbook data is to account for the heterogeneity of fishing practices (e.g., by gear or métier), which is a key aspect of the Common Fishery Policy. However, despite their importance, few published studies have explored the potential and pitfalls of logbook data, even in combination with other powerful data sources such as the Vessel Monitoring System (VMS). Here, a new approach to characterizing the composition of landings for the different types of gear based on the use of Self-Organizing Maps (SOMs − a particular type of Artificial Neural Network) is applied to the Italian fleet logbook dataset. The SOM is trained on the landings composition and the resulting patterns are interpreted using some measures obtained from the analysis of the corresponding VMS data. Namely, the mean sea bottom depth and the area of activity are obtained for each fishing trip. Moreover, the ability of the trained SOM to predict gear from landings is tested using a new dataset. The trained SOM classifies logbook records according to the ecological, taxonomical, and trophic characteristics of the species caught, and the depth of fishing activities plays an important role in diversifying the landings associated with certain widely used fishing gear such as the bottom otter trawl. The clustering of SOM units allows the identification of a set of 12 groups, which are strongly related to the types of gear used by the Italian fleet. Furthermore, the trained SOM shows a high ability to recognize gear from logbook data, thus confirming the robustness of the landings profiles detected.

In Vitro Validation of a Closed Device Enabling the Purification of the Fluid Portion of Liposuction Aspirates.

Adipose tissue harvested through lipoaspiration is widely exploited in plastic and cosmetic surgery, because of its remarkable trophic properties, especially relying on the presence of adipose-derived stem cells. The common procedures for adipose-derived stem cell isolation are mainly based on tissue fractionation and enzymatic digestion, requiring multiple hours of uninterrupted work, unsuitable for direct surgical applications. Recent studies demonstrated the feasibility of isolating adipose stromal cells without the need for enzymatic digestion. These studies reported the processing of the fluid portion of liposuctioned adipose tissue (lipoaspirate fluid), which contains a significant amount of progenitor cells endowed with plastic and trophic features. In this article, the authors introduce a brand new closed device--the MyStem EVO kit--which allows nonenzymatic tissue separation and rapid isolation of lipoaspirate fluid from human liposuctioned adipose tissue. Adipose tissue was liposuctioned from 14 donors, split into aliquots, and alternatively processed using either centrifugation or the MyStem EVO kit, to separate fatty and lipoaspirate fluid portions. The samples were analyzed comparatively by flow cytometry, histology, and differentiation assays. Osteoinductive and angioinductive features were analyzed through in vitro co-culture assays. The alternative procedures enabled comparable yields; the kit rapidly isolated lipoaspirate fluid comprising a homogenous cell population with adipose stem cell immunophenotype, bilineage potential, and efficient osteoinductive and angioinductive features. MyStem EVO allows the rapid isolation of lipoaspirate fluid with trophic properties within a closed system, and is potentially useful for regenerative medicine applications.

Monitoring and assessment of anthropogenic activities in mountain lakes: a case of the Fifth Triglav Lake in the Julian Alps.

The Fifth Triglav Lake is a remote mountain lake in the Julian Alps. The area of the Julian Alps where the lake is situated is protected by law and lies within the Triglav National Park. Mountain lakes in Slovenia were considered for a long time as pristine, unpolluted lakes, but analyses in the last decade revealed considerable human impact even in such remote places. Eutrophication or excessive accumulation of nutrients is the main problem of most lakes in the temperate climatic zone, also in Slovenia. Since the introduction of fish in 1991, the lake is going through a series of changes for which we do not know exactly where they lead, so the monitoring and assessment of anthropogenic activities are of great importance. For this purpose, a qualitative multiattribute decision model was developed with DEX method to assess ecological effects on the lake. The extent of the ecological effects on the lake is assessed using four main parameters: the trophic state, lake characteristics, environmental parameters, and anthropogenic stressors. Dependence of environmental impact on various external factors beyond human control, such as temperature, precipitation, retention time, and factors on which we have influence, such as the amount of wastewater and the presence of fish in the lake, were also evaluated. The following data were measured: chlorophyll a, nutrients, TP, oxygen, C/N ratio, nutrients in sediment, temperature, precipitation, retention time, and volume. We made assumptions about fish and wastewater, which we could not measure. The main contributions of this work are the designed model and the obtained findings for the Fifth Triglav Lake that can help not only scientists in understanding the complexity of lake-watershed systems and interactions among system components but also local authorities to manage and monitor the lake aquatic environment in an effective and efficient way. The model is flexible and can be also used for other lakes, assuming that the used parameters are measured and anthropogenic stressors are adjusted to a specific situation. The results of assessment are of particular interest for decision makers in protected areas, providing a new approach to the management of the quality of the water environment.

Drivers of highly diverse planktonic ciliate assemblages in peat bog pools from Tierra del Fuego (Argentina)

Peatlands often encompass shallow pools, wherein dystrophic and colored acid waters host a remarkably diverse biota, with ciliates likely playing a key role in their short trophic webs. In the Sphagnum magellanicum-dominated Rancho Hambre peat bog, a 2-year study was conducted in five pools with different morphometric and trophic characteristics, in order to identify main environmental variables driving ciliate species richness, abundance, biomass, and diversity. Overall species richness (125 taxa) was much higher than in northern Hemisphere counterparts. Deep minerotrophic pools hosted the richest communities, showing similar seasonal abundance patterns and the highest species turnover. Although all pools shared the same dominant ciliates, similarity in taxonomic composition among them was generally low (J = 0.22–0.35). Moreover, IndVal analysis showed that rare and occasional species were highly indicative of different pools. Euryoecious, heterotrophic species, occurred in all sites, while mixotrophs were typical from shallow ombrotrophic pools. Rimostrombidium hyalinum was the most indicative species of a deep ombrotrophic pool. A CCA revealed that the abundances of potential ciliate preys, i.e., picophytoplankton, bacterioplankton, and heterotrophic flagellates, were the most significant regulators of abundances of this group. Therefore, ciliate structure and dynamics were influenced by pool morphometry and physical and chemical features, but foremost by interactions with other plankton communities.

Morpho-functional analysis of the jaw apparatus of Vietnamese Passerine birds (Passeriformes): inferences on their trophic adaptations, ecology, and systematic position

The biology of many forest birds of Southeast Asia is still poorly known and requires extensive and intensive field study. Field data on trophic features of forest Passerine birds were collected in more than 15 forest areas in all main natural zones of the country during an ecological research program at the Russian-Vietnamese Tropical Research Centre in Vietnam in 1989–2013. The morpho-functional analysis of the jaw apparatus has been used to interpret field observations and to infer certain aspects of the feeding biology in the absence of direct observations. The analytical method comprises a detailed description of the morphology and a subsequent biomechanical analysis of the jaw apparatus as a basis for the reconstruction of the evolution of trophic adaptations in selected species and groups. A comparison of several congeneric species provided insights into the feeding adaptations in several genera of bulbuls and timaliid species and of several other Passerine families. Besides data on 16 picnonotid species and 11 timaliid species, data on selected representatives of Corvidae, Rhipiduridae, Oriolidae, Campephagidae, Dicruridae, Chloropseidae, Irenidae, Monarchidae, Aegithinidae, Dicaeidae, Nectarinidae, Sturnidae, Muscicapidae, and Zosteropidae were collected to identify their trophic adaptations. Our morpho-functional data show various degrees of specialization for different trophic strategies, such as insectivory, frugivory, nectarivory, predation, seed-eating, or eating of other plant matter. Several conclusions on the systematics of Old World Passerines based on these data are also presented.