Mercury in Macroinvertebrates from Swedish Forest Lakes: Influence of Lake Type, Habitat, Life Cycle, and Food Quality

1993 ◽  
Vol 50 (3) ◽  
pp. 521-534 ◽  
Author(s):  
Helena Parkman ◽  
Markus Meili
Keyword(s):  
Life Cycle ◽  
Food Quality ◽  
Climatic Factors ◽  
Feeding Habits ◽  
Ecological Factors ◽  
Dry Weight ◽  
Taxonomic Composition ◽  
Sediment Chemistry ◽  
Ecological Niches ◽  
Forest Lakes

Mercury concentrations in lacustrine macroinvertebrates were concurrently studied in eight remote Swedish forest lakes of differing dystrophy, acidity, and eutrophy. The aim was to assess the influence of ecological factors (taxon, habitat, and feeding habits), chemical factors (characterizing different types of lakes), and regional and climatic factors (Hg deposition and mean temperature) on the accumulation of Hg. Concentrations varied from <50 to >5000 ng Hg∙g dry weight−1. A large part of this high variability could be ascribed to differences in water and sediment chemistry, ecological niches, and species-specific seasonalities. Both taxonomic composition and Hg concentrations were highly dependent on the type of lake. Concentrations were highest in acidic dystrophic lakes and lowest in oligotrophic lakes. Mean Hg concentrations in the examined taxa within a lake differed 100-fold. Contrary to widely held views on biomagnification, the lowest concentrations among profundal chironomids were found in predators whereas the highest concentrations occurred in detritivores. Seasonal variations were negligible in some taxa but considerable in others and appeared in some taxa to be related to the life cycle. We conclude that Hg accumulation in macroinvertebrates is largely determined by feeding behaviour and food quality.

scholarly journals Nematode Hsp90: highly conserved but functionally diverse

Parasitology ◽  
2014 ◽  
Vol 141 (9) ◽  
pp. 1203-1215 ◽  
Author(s):  
VICTORIA GILLAN ◽  
EILEEN DEVANEY
Keyword(s):  
Life Cycle ◽  
Heat Shock Protein 90 ◽  
Ecological Niches ◽  
Actual Number ◽  
Host Organism ◽  
Free Living ◽  
Parasitic Species ◽  
Free Living Nematode ◽  
Functionally Diverse

SUMMARYNematodes are amongst the most successful and abundant organisms on the planet with approximately 30 000 species described, although the actual number of species is estimated to be one million or more. Despite sharing a relatively simple and invariant body plan, there is considerable diversity within the phylum. Nematodes have evolved to colonize most ecological niches, and can be free-living or can parasitize plants or animals to the detriment of the host organism. In this review we consider the role of heat shock protein 90 (Hsp90) in the nematode life cycle. We describe studies on Hsp90 in the free-living nematode Caenorhabditis elegans and comparative work on the parasitic species Brugia pahangi, and consider whether a dependence upon Hsp90 can be exploited for the control of parasitic species.

COMPREHENSIVE WAY OF CALCULATING ECOLOGICAL (ENVIRONMENTAL SPACE) FACTORS OF PLANT COMMUNITIES ENVIRONMENT FOR AMPLITUDE ECOLOGICAL SCALES

2021 ◽  
Vol 92 (2) ◽  
pp. 48-58
Author(s):  
G. N. Buzuk ◽  
Keyword(s):  
Plant Communities ◽  
Climatic Factors ◽  
Ecological Factors ◽  
Indicator Method ◽  
Ecological Index ◽  
Ecological Scales ◽  
Ecological Scale ◽  
Environmental Space ◽  
Instrumental Methods ◽  
The Ideal

Despite intensive development of instrumental methods of environmental factors analysis for plant communities their assessment with ecological scales still remains important. The main advantage of ecological scales is their ability to reflect generalized and average characteristics of ecological regimes due to significant inertia in response of plant communities composition to the change of certain characteristics of the environment. The main ways of calculation while using ecological scales are the medium-sized method and the ideal indicator method (of linear regression) including modified algorithm of calculating the level of edaphic and climatic factors of the environment with amplitude ecological scales. The aim of this work was to improve further the method for assessing the level of ecological factors (ecological space) in plant communities. For calculations and visualization of the results obtained we used Excel and our own programs written in the Matlab media. The basis of the method is finding the factor averagely weighed for the level calculated by the traditional way and by the method of the ideal indicator. It is proposed to set the weight of factors in both methods of calculation both explicitly and depending on the ecological index reflecting correspondence (adequacy) of the plant community composition to the level of ecological factors prevailing in the habitat. They can also be calculated by linear or non-linear dependencies relative to the middle of amplitude ecological scale. The conclusion is that it is possible to predict the content of secondary metabolites in plants based on assessing the level of ecological factors for plant communities.

scholarly journals Phytoplankton assemblages in Lake Orta: has functional structure recovered in one of the largest acidic lakes in the world?

2016 ◽  
Vol 75 (s2) ◽  
Author(s):  
Giuseppe Morabito
Keyword(s):  
Functional Groups ◽  
Diversity Indices ◽  
Taxonomic Composition ◽  
Ecological Niches ◽  
Phytoplankton Species ◽  
Phytoplankton Assemblages ◽  
Lake Maggiore ◽  
Acidic Lakes ◽  
Physical Features ◽  
She Analysis

Lake Orta (Northern Italy) became one of the world’s largest acidic lakes, following industrial pollution, beginning in the late 1920s. Prior to pollution, Lake Orta supported a rich and diversified phytoplankton community dominated by diatoms, cyanobacteria and dinoflagellates. Their taxonomic composition was comparable to that of the nearby Lake Maggiore, which provides a useful reference comparison. After pollution, Lake Orta was so acidic and contaminated with trace metals that only a few tolerant phytoplankton species persisted, supplemented by sudden and short living outbursts of occasional colonists. The lake was limed in 1989-1990. This has permitted the gradual recovery of its chemistry and biology, and many phytoplankton species that inhabit Lake Maggiore are now re-appearing in Lake Orta. I tested the two hypotheses that Lakes Orta and Maggiore would now have a similar phytoplankton taxonomic assemblages, and similar diversity of functional groups given their similar morphometry, physical features and trophic states. The two hypotheses were tested by comparing the phytoplankton assemblages of lakes Maggiore and Orta for the first 10 years after liming, i.e. 1990 to 2001. Phytoplankton was classified according the Reynolds' Morpho Functional Groups and five diversity indices were calculated (<em>S</em>, number of units; <em>H</em>, Shannon-Wiener; <em>E</em>, evenness; <em>D</em>, dominance; <em>J</em>, equitability). SHE analysis (an analysis of diversity changes based on the relationship among species richness (S), H Index (H) and evenness (E)) was also carried out, in order to compare the long term trend of both functional groups and taxa biodiversity. Both taxonomic and the functional composition differed in the two lakes, likely because chemical quality have played a role in <em>taxa</em>selection. Moreover, it was quite clear that, during the first post-liming decade, Lake Orta’s phytoplankton was characterized by low diversity and evenness and by marked year-to-year fluctuations. However, SHE analysis showed that the colonization rate was higher in Lake Orta than in Lake Maggiore, and that the environmental modifications caused by the liming were opening new ecological niches, allowing some colonists to thrive in the changing, albeit still unusual chemical environment of the lake.<p> </p>

scholarly journals Feeding habits of capybaras (Hydrochoerus hydrochaeris, Linnaeus 1766), in the Ecological Reserve of Taim (ESEC - Taim) - south of Brazil

2007 ◽  
Vol 50 (3) ◽  
pp. 409-416 ◽  
Author(s):  
Lucélia do Valle Borges ◽  
Ioni Gonçalves Colares
Keyword(s):  
Food Quality ◽  
Feeding Habits ◽  
Opportunistic Behavior ◽  
Frequent Species ◽  
Hydrochoerus Hydrochaeris ◽  
Ecological Reserve ◽  
Varied Diet ◽  
South Of Brazil ◽  
Selective Behavior

The aim of this study was to determine feeding habitats of capybaras in the ESEC-Taim (RS, Brazil), using microhistological analyses of feces. Data were analyzed seasonally. In 172 samples analyzed, 17 species were identified, with predominance of Poaceae. Zizaniopsis bonariensis was the most frequent species in winter (38%), spring (32%) and summer (26.5%) and Paspalum disthichum in fall (31.5%). A observed increase in vegetation consumption during summer might be due to the food quality. Capybaras showed an opportunistic behavior in the winter and summer and a more selective behavior in spring and fall. Capybaras from the ESEC-Taim varied diet according to the season and alimentary availability.

scholarly journals Structure of the phytoplankton community in the Cachoeira Dourada reservoir (GO/MG), Brazil

2011 ◽  
Vol 71 (3) ◽  
pp. 587-600 ◽  
Author(s):  
M. Teixeira de Oliveira ◽  
O. Rocha ◽  
AC. Peret
Keyword(s):  
Phytoplankton Community ◽  
Driving Forces ◽  
Climatic Factors ◽  
Euphotic Zone ◽  
Taxonomic Composition ◽  
Nitrogen And Phosphorus ◽  
Physical And Chemical Variables ◽  
Algal Assemblages ◽  
Physical And Chemical

The limnological features and the phytoplankton community of the Cachoeira Dourada reservoir were analyzed in December 2006, May 2007 and November 2007. Temporal changes in the taxonomic composition, density, diversity and dominance of species were analyzed in relation to climatic factors and the physical and chemical characteristics of the water. A positive correlation was found between some of the physical and chemical variables and the phytoplankton community. According to the CCA, variables such as the extent of the euphotic zone, temperature, pH, nitrogen and phosphorus concentrations directly affected the phytoplankton dynamics. Organisms belonging to the class Cyanophyceae were the most representative in all the sampling periods, comprising the functional groups K, S1, M and H. Hydrodynamics and seasonal fluctuations of environmental factors were the driving forces determining the composition and abundance of the algal assemblages. Despite the prevalence of Cyanobacteria, the reservoir is still oligotrophic. The absence of blooms and the relatively low population abundances indicated that the quality of the reservoir's water still lies within the limits required for its multiples uses.

Seasonal Variation In The Composition Of Epicuticular Waxes Of Quevcus Robur Leaves

1992 ◽  
Vol 47 (11-12) ◽  
pp. 800-806 ◽  
Author(s):  
P.-G. Gülz ◽  
E. Müller
Keyword(s):  
Fatty Acids ◽  
Climatic Factors ◽  
Dry Weight ◽  
Vegetation Period ◽  
Wax Ester ◽  
Primary Alcohols ◽  
Mean Values ◽  
Leaf Surface Area ◽  
Ester Biosynthesis ◽  
Genetically Determined

The epicuticular leaf waxes of Quercus robur were analyzed continuously over a two years vegetation period with preparation every week from April to November. The folded leaflets in buds have waxes quite different in yield and composition from those of mature leaves. They contain homologous series of hydrocarbons, wax esters, primary alcohols, fatty acids and triterpenoids from the beginning, but not aldehydes. After leaf unfolding a dynamic biosynthesis of alcohols, aldehydes and fatty acids is observed in May and June. Wax content is doubled per dry weight or in cm2 leaf surface area and 80-fold per one leaf in that time. During leaf development tetracosanol becomes the dominant epicuticular wax component comprising ca. 40% of the wax. In both years of the study a reactivation of wax ester biosynthesis is observed in October and November. Esters with chain length C36 and C38 increased particularly. From July to November the wax composition remained nearly constant within mean values and their standard deviations. Within the two years studied most values concerning wax composition are reproducible and are therefore genetically determined. In spring the growing processes are influenced by climatic factors

scholarly journals Can mandible morphology help predict feeding habits in Antarctic amphipods?

2020 ◽  
Vol 32 (6) ◽  
pp. 496-507
Author(s):  
Loïc N. Michel ◽  
Fabienne L. Nyssen ◽  
Patrick Dauby ◽  
Marie Verheye
Keyword(s):  
Functional Groups ◽  
Trophic Ecology ◽  
Feeding Habits ◽  
Gut Contents ◽  
Ecological Niches ◽  
Feeding Strategies ◽  
Generalist Predators ◽  
Dietary Specialization ◽  
Important Place ◽  
Antarctic Amphipod

AbstractIn Antarctica, amphipods form a highly diverse group, occupy many different ecological niches and hold an important place in food webs. Here, we aimed to test whether differences in Antarctic amphipod feeding habits were reflected in their mandible morphology, and if mouthpart specialization could be used to describe amphipod trophic ecology. To do so, we compared mandible morphology in nine species spanning seven families and five functional groups (grazers, suspension feeders, generalist predators, specialist predators and scavengers). Mandible morphology adequately depicted some aspects of amphipod trophic ecology, such as the trophic level at which animals feed or their degree of dietary specialization. On the other hand, links between mandible morphology and amphipod diet were seldom unambiguous or straightforward. Similar adaptations were found in distinct functional groups. Conversely, mandible morphology could vary within a single functional group, and phylogenetic effects sometimes complicated the interpretation of form-function relationships. Overall, mandible morphology on its own was generally not sufficient to precisely predict amphipod feeding strategies. However, when combined with other methods (e.g. gut contents, trophic markers), it constitutes a valuable source of information for integrative studies of amphipod ecological diversity in the Southern Ocean.

scholarly journals Epidemiology and hypothetical transmission cycles of Trichinella infections in the Greater Kruger National Park of South Africa: an example of host-parasite interactions in an environment with minimal human interactions

Parasite ◽  
2020 ◽  
Vol 27 ◽  
pp. 13
Author(s):  
Louis J. La Grange ◽  
Samson Mukaratirwa
Keyword(s):  
South Africa ◽  
Protected Areas ◽  
National Parks ◽  
National Park ◽  
Feeding Habits ◽  
Kruger National Park ◽  
Sub Saharan Africa ◽  
Ecological Niches ◽  
Transmission Cycles ◽  
Sub Saharan

Knowledge on the epidemiology, host range and transmission of Trichinella spp. infections in different ecological zones in southern Africa including areas of wildlife-human interface is limited. The majority of reports on Trichinella infections in sub-Saharan Africa were from wildlife resident in protected areas. Elucidation of the epidemiology of the infections and the prediction of hosts involved in the sylvatic cycles within specific ecological niches is critical. Of recent, there have been reports of Trichinella infections in several wildlife species within the Greater Kruger National Park (GKNP) of South Africa, which has prompted the revision and update of published hypothetical transmission cycles including the hypothetical options based previously on the biology and feeding behaviour of wildlife hosts confined to the GKNP. Using data gathered from surveillance studies and reports spanning the period 1964–2019, confirmed transmission cycles and revised hypothesized transmission cycles of three known Trichinella species (T. zimbabwensis, Trichinella T8 and T. nelsoni) are presented. These were formulated based on the epidemiological factors, feeding habits of hosts and prevalence data gathered from the GKNP. We presume that the formulated sylvatic cycles may be extrapolated to similar national parks and wildlife protected areas in sub-Saharan Africa where the same host and parasite species are known to occur. The anecdotal nature of some of the presented data confirms the need for more intense epidemiological surveillance in national parks and wildlife protected areas in the rest of sub-Saharan Africa to unravel the epidemiology of Trichinella infections in these unique and diverse protected landscapes.

scholarly journals Seasonal dynamics of cyanobacteria in a eutrophic reservoir (Arcoverde) in a semi-arid region of Brazil

2012 ◽  
Vol 72 (3) ◽  
pp. 533-544 ◽  
Author(s):  
MC. Bittencourt-Oliveira ◽  
SN. Dias ◽  
AN. Moura ◽  
MK. Cordeiro-Araújo ◽  
EW. Dantas
Keyword(s):  
Phytoplankton Community ◽  
Climatic Factors ◽  
Principal Component ◽  
Taxonomic Composition ◽  
Dry Season ◽  
Northeastern Brazil ◽  
Cylindrospermopsis Raciborskii ◽  
Physical And Chemical Variables ◽  
Semi Arid Region ◽  
Cyanobacterial Biomass

Environmental conditions favor the predominance of dense populations of cyanobacteria in reservoirs in northeastern Brazil. The aim of this study was to understand cyanobacterial population dynamics in the rainy and dry seasons at two depths in the Arcoverde reservoir. Microalgae and cyanobacteria samples were collected during 24 hours with intervals of 4 hours (nycthemeral) at sub-surface and 10 m using a van Dorn bottle and a determined biomass. Physical and chemical variables were obtained and the data were analyzed using the principal component analysis (PCA). No nycthemeral variations in the taxonomic composition or distribution of the populations of cyanobacteria were found between the different times of day in either the rainy or dry season. In both seasons, the greatest biomass of the phytoplankton community was made up of cyanobacteria at two depths and all times of the day. Cylindrospermopsis raciborskii (Woloszynska) Seenayya et Subba Raju was dominant at all times of the day on both the surface and at the bottom. In the rainy season, the differences in cyanobacterial biomass between the surface and bottom were less significant than in the dry season. The differences in cyanobacterial biomass between surface and bottom were less pronounced than those found in the dry season. We concluded that a) physical variables better explain the alterations of species in the phytoplankton community in an environment dominated by cyanobacteria throughout the year; b) seasonal climatic factors associated to periods of stratification and de-stratification are important for alterations in the community and variations in biomass and, c) the turbidity caused by rainfall favored the emergence and establishment of other cyanobacteria, especially Planktothrix agardhii (Gomont) Anagnostidis & Komárek.

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