Search results for "lcsh:QH540-549.5"
showing 10 items of 117 documents
Semiochemical exploitation of host-associated cues by seven Melittobia parasitoid species : Behavioral and phylogenetic implications
2018
Chemical compounds (infochemicals or semiochemicals) play an important role both in intra-specific and inter-specific communication. For example, chemical cues appear to play a key role in the host selection process adopted by insect parasitoids. In recent years significant advances have been made in order to understand the chemical ecology of insect parasitoids. However, little information is available about the evolution of semiochemical use in the host location process of insect parasitoids. Here we investigated the strategy adopted by seven closely related parasitoid species in the genus Melittobia when foraging for four different suitable hosts. By using an integrated approach that com…
Community composition and seasonal changes of archaea in coarse and fine air particulate matter
2018
Archaea are ubiquitous in terrestrial and marine environments and play an important role in biogeochemical cycles. Although air acts as the primary medium for their dispersal among different habitats, their diversity and abundance is not well characterized. The main reason for this lack of insight is that archaea are difficult to culture, seem to be low in number in the atmosphere, and have so far been difficult to detect even with molecular genetic approaches. However, to better understand the transport, residence time, and living conditions of microorganisms in the atmosphere as well as their effects on the atmosphere and vice versa, it is essential to study all groups of bioaerosols. Her…
Snowpack concentrations and estimated fluxes of volatile organic compounds in a boreal forest
2012
Abstract. Soil provides an important source of volatile organic compounds (VOCs) to atmosphere, but in boreal forests these fluxes and their seasonal variations have not been characterized in detail. Especially wintertime fluxes are almost completely unstudied. In this study, we measured the VOC concentrations inside the snowpack in a boreal Scots pine (Pinus sylvestris L.) forest in southern Finland, using adsorbent tubes and air samplers installed permanently in the snow profile. Based on the VOC concentrations at three heights inside the snowpack, we estimated the fluxes of these gases. We measured 20 VOCs from the snowpack, monoterpenes being the most abundant group with concentrations …
Microbiology and atmospheric processes: research challenges concerning the impact of airborne micro-organisms on the atmosphere and climate
2011
Cet article a fait l'objet d'une discussion dans "Morris, C. E., Sands, D. C., Bardin, M., Jaenicke, R., Vogel, B., Leyronas, C., Ariya, P. A., and Psenner, R.: Microbiology and atmospheric processes: an upcoming era of research on bio-meteorology, Biogeosciences Discuss., 5, 191-212, doi:10.5194/bgd-5-191-2008, 2008."; International audience; For the past 200 years, the field of aerobiology has explored the abundance, diversity, survival and transport of micro-organisms in the atmosphere. Micro-organisms have been explored as passive and severely stressed riders of atmospheric transport systems. Recently, an interest in the active roles of these micro-organisms has emerged along with prop…
The role of parasitism in adaptive radiations – when might parasites promote and when might they constrain ecological speciation?
2012
Research on speciation and adaptive radiation has flourished during the past decades, yet factors underlying initiation of reproductive isolation often remain unknown. Parasites represent important selective agents and have received renewed attention in speciation research. We review the literature on parasite-mediated divergent selection in context of ecological speciation and present empirical evidence for three nonexclusive mechanisms by which parasites might facilitate speciation: reduced viability or fecundity of immigrants and hybrids, assortative mating as a pleiotropic by-product of host adaptation, and ecologically-based sexual selection. We emphasise the lack of research on specia…
The biocenotic value of Slitere National Park, Latvia, with special reference to inter-dune mires
2019
Inter-dune wetlands in Europe harbour many Red List species because they are very nutrient-poor ecosystems. Most of these wetlands are geologically very young and no or little peat formation has occurred. In Slītere National Park the numerous inter-dune wetlands are relatively old, up to 4500 years old, and most mire communities are peat forming and they are well preserved. However, the hydrological systems that have conserved the mires are largely unknown. In the present study we analysed 128 vegetation relevées of dune mires in order to assess the variation in ecological mire types. We also carried out several short-time studies to get an insight into the peat development and hydrological…
Chemical composition of modern and fossil hippopotamid teeth and implications for paleoenvironmental reconstructions and enamel formation – Part 2: A…
2012
Abstract. For reconstructing environmental change in terrestrial realms the geochemistry of fossil bioapatite in bones and teeth is among the most promising applications. This study demonstrates that alkaline earth elements in enamel of Hippopotamids, in particular Ba and Sr are tracers for water provenance and hydrochemistry. The studied specimens are molar teeth from Hippopotamids found in modern and fossil lacustrine settings of the Western Branch of the East African Rift system (Lake Kikorongo, Lake Albert, and Lake Malawi) and from modern fluvial environments of the Nile River. Concentrations in enamel vary by ca. two orders of magnitude for Ba (120–9336 μg g−1) as well as for Sr (9–21…
Drivers of peat accumulation rate in a raised bog: impact of drainage, climate, and local vegetation composition
2017
We used variation partitioning to assess the relative importance of drainage, climate and local vegetation composition for the development of a raised bog. As a case study we selected Teici (Teici) Bog in Latvia (north-east Europe). Explanatory variables together explained 74 % of the variation in peat accumulation and only the residue of 26 % remained unexplained. Our study showed that the local vegetation composition and dominant Sphagnum species significantly influence peat accumulation rates. The results of linear models revealed that, under natural conditions, minor drainage and even strong drainage of the peat is associated with a positive growth balance of the system. However, draina…
Conservation implications of species–genetic diversity correlations
2014
Despite its importance for the long-term viability of populations and functioning of ecosystems, the genetic diversity of populations is seldom given explicit consideration in conservation prioritization. Research on the species–genetic diversity correlation (SGDC) suggests that species diversity within a community and intrapopulation genetic diversity are positively correlated, due to the parallel influences of environmental characteristics (area, connectivity, and environmental heterogeneity) on both levels of diversity. A positive locality scale SGDC (i.e. α-SGDC) thus provides potential for simultaneous conservation of both species diversity within a locality and intrapopulation genetic…
Características de las costras físicas y biológicas del suelo con mayor influencia sobre la infiltración y la erosión en ecosistemas mediterráneos
2010
28 páginas, 4 figuras, 5 tablas.