biogeochemistry
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elektronický časopis
- Konspekt
- Biochemie. Molekulární biologie. Biofyzika
- NLK Obory
- biochemie
- NLK Publikační typ
- elektronické časopisy
Semivolatile persistent organic pollutants (POP) are bioaccumulative and toxic contaminants. Their global distribution depends on source distribution, atmospheric transport, degradation, and the exchange with ocean and land surfaces. Forests are crucial terrestrial reservoirs due to the commonly envisaged high capacity of their surface soils to store and immobilize airborne contaminants bound to soil organic matter. Our results show that POPs can be unexpectedly mobile in the soil of a tropical rainforest due to fast litter turnover (leading to rapid POP transfer to the subsoil) and leaching rates exceeding degradation rates especially for more hydrophobic congeners. Co-transport in association with leaching fine particulate and dissolved organic matter appears as a relevant driver of this PCB export. A markedly different distribution pattern is displayed in this soil in comparison to soils of colder environments with lower overall storage capacity. These findings show that biogeochemistry of organic matter degradation and weathering can influence POP soil fate. Because tropical forests represent 60% of the global terrestrial productivity, the highlighted dynamics might have an implication for the general distribution of these contaminants.
Human activities are altering the fundamental geography of biogeochemicals. Yet we lack an understanding of how the spatial patterns in organismal stoichiometry affect biogeochemical processes and the tools to predict the impacts of global changes on biogeochemical processes. In this contribution we develop stoichiometric distribution models (StDMs), which allow us to map spatial structure in resource elemental composition across a landscape and evaluate spatial responses of consumers. We parameterise StDMs for a consumer-resource (moose-white birch) system and demonstrate that we can develop predictive models of resource stoichiometry across a landscape and that such models could improve our predictions of consumer space use. With results from our study system application, we argue that explicit consideration of the spatial patterns in organismal elemental composition may uncover emergent individual, population, community and ecosystem properties that are not revealed at the local extents routinely used in ecological stoichiometry. We discuss perspectives for further developments and application of StDMs to advance three emerging frameworks for spatial ecosystem ecology in an era of global change; meta-ecosystem theory, macroecological stoichiometry and remotely sensed biogeochemistry. Progress on these emerging frameworks will allow for the integration of ecological stoichiometry and individual space use and fitness.
- MeSH
- biologické modely MeSH
- ekologie * MeSH
- ekosystém * MeSH
- lidé MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
Peatland vegetation is composed mostly of mosses, graminoids and ericoid shrubs, and these have a distinct impact on peat biogeochemistry. We studied variation in soil microbial communities related to natural peatland microhabitats dominated by Sphagnum, cotton-grass and blueberry. We hypothesized that such microhabitats will be occupied by structurally and functionally different microbial communities, which will vary further during the vegetation season due to changes in temperature and photosynthetic activity of plant dominants. This was addressed using amplicon-based sequencing of prokaryotic and fungal rDNA and qPCR with respect to methane-cycling communities. Fungal communities were highly microhabitat-specific, while prokaryotic communities were additionally directed by soil pH and total N content. Seasonal alternations in microbial community composition were less important; however, they influenced the abundance of methane-cycling communities. Cotton-grass and blueberry bacterial communities contained relatively more α-Proteobacteria but less Chloroflexi, Fibrobacteres, Firmicutes, NC10, OD1 and Spirochaetes than in Sphagnum. Methanogens, syntrophic and anaerobic bacteria (i.e. Clostridiales, Bacteroidales, Opitutae, Chloroflexi and Syntrophorhabdaceae) were suppressed in blueberry indicating greater aeration that enhanced abundance of fungi (mainly Archaeorhizomycetes) and resulted in the highest fungi-to-bacteria ratio. Thus, microhabitats dominated by different vascular plants are inhabited by unique microbial communities, contributing greatly to spatial functional diversity within peatlands.
- MeSH
- Bacteria klasifikace genetika izolace a purifikace metabolismus MeSH
- brusnice s jedlými plody růst a vývoj mikrobiologie MeSH
- houby klasifikace genetika izolace a purifikace metabolismus MeSH
- lipnicovité růst a vývoj mikrobiologie MeSH
- methan metabolismus MeSH
- mikrobiota MeSH
- půda chemie MeSH
- půdní mikrobiologie * MeSH
- rašeliníky růst a vývoj mikrobiologie MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Research Support, N.I.H., Extramural MeSH
Assessing phytoplankton productivity over space and time remains a core goal for oceanographers and limnologists. Fast Repetition Rate fluorometry (FRRf) provides a potential means to realize this goal with unprecedented resolution and scale yet has not become the "go-to" method despite high expectations. A major obstacle is difficulty converting electron transfer rates to equivalent rates of C-fixation most relevant for studies of biogeochemical C-fluxes. Such difficulty stems from methodological inconsistencies and our limited understanding of how the electron requirement for C-fixation (Φe,C) is influenced by the environment and by differences in the composition and physiology of phytoplankton assemblages. We outline a "roadmap" for limiting methodological bias and to develop a more mechanistic understanding of the ecophysiology underlying Φe,C. We 1) re-evaluate core physiological processes governing how microalgae invest photosynthetic electron transport-derived energy and reductant into stored carbon versus alternative sinks. Then, we 2) outline steps to facilitate broader uptake and exploitation of FRRf, which could transform our knowledge of aquatic primary productivity. We argue it is time to 3) revise our historic methodological focus on carbon as the currency of choice, to 4) better appreciate that electron transport fundamentally drives ecosystem biogeochemistry, modulates cell-to-cell interactions, and ultimately modifies community biomass and structure.
- MeSH
- chlorofyl a * MeSH
- chlorofyl MeSH
- ekosystém * MeSH
- fotosyntéza MeSH
- fytoplankton MeSH
- sladká voda MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Disturbances are intrinsic drivers of structure and function in ecosystems, hence predicting their effects in forest ecosystems is essential for forest conservation and/or management practices. Yet, knowledge regarding belowground impacts of disturbance events still remains little understood and can greatly vary by taxonomic and functional identity, disturbance type and local environmental conditions. To address this gap in knowledge, we conducted a survey of soil-dwelling Protura, across forests subjected to different disturbance regimes (i.e. windstorms, insect pest outbreaks and clear-cut logging). We expected that the soil proturan assemblages would differ among disturbance regimes. We also hypothesized that these differences would be driven primarily by variation in soil physicochemical properties thus the impacts of forest disturbances would be indirect and related to changes in food resources. To verify that sampling included two geographically distant subalpine glacial lake catchments that differed in underlying geology, each having four different types of forest disturbance, i.e. control, bark beetle outbreak (BB), windthrow + BB (wind + BB) and clear-cut. As expected, forest disturbance had negative effects on proturan diversity and abundance, with multiple disturbances having the greatest impacts. However, differences in edaphic factors constituted a stronger driver of variability in distribution and abundance of proturans assemblages. These results imply that soil biogeochemistry and resource availability can have much stronger effects on proturan assemblages than forest disturbances.
- MeSH
- biodiverzita MeSH
- brouci růst a vývoj MeSH
- členovci růst a vývoj MeSH
- ekosystém MeSH
- jezera MeSH
- lesy MeSH
- půda MeSH
- stromy fyziologie MeSH
- zachování přírodních zdrojů MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Marine-to-terrestrial transition represents one of the most fundamental shifts in microbial life. Understanding the distribution and drivers of soil microbial communities across coastal ecosystems is critical given the roles of microbes in soil biogeochemistry and their multifaceted influence on landscape succession. Here, we studied the fungal community dynamics in a well-established salt marsh chronosequence that spans over a century of ecosystem development. We focussed on providing high-resolution assessments of community composition, diversity and ecophysiological shifts that yielded patterns of ecological succession through soil formation. Notably, despite containing 10- to 100-fold lower fungal internal transcribed spacer abundances, early-successional sites revealed fungal richnesses comparable to those of more mature soils. These newly formed sites also exhibited significant temporal variations in β-diversity that may be attributed to the highly dynamic nature of the system imposed by the tidal regime. The fungal community compositions and ecophysiological assignments changed substantially along the successional gradient, revealing a clear signature of ecological replacement and gradually transforming the environment from a marine into a terrestrial system. Moreover, distance-based linear modelling revealed soil physical structure and organic matter to be the best predictors of the shifts in fungal β-diversity along the chronosequence. Taken together, our study lays the basis for a better understanding of the spatiotemporally determined fungal community dynamics in salt marshes and highlights their ecophysiological traits and adaptation in an evolving ecosystem.
Urbanization has the potential to dramatically alter the biogeochemistry of receiving freshwater ecosystems. We examined the optical chemistry of dissolved organic matter (DOM) in forty-five urban ponds across southern Ontario, Canada to examine whether optical characteristics in these relatively new ecosystems are distinct from other freshwater systems. Dissolved organic carbon (DOC) concentrations ranged from 2 to 16 mg C L(-1) across the ponds with an average value of 5.3 mg C L(-1). Excitation-emission matrix (EEM) spectroscopy and parallel factor analysis (PARAFAC) modelling showed urban pond DOM to be characterized by microbial-like and, less importantly, by terrestrial derived humic-like components. The relatively transparent, non-humic DOM in urban ponds was more similar to that found in open water, lake ecosystems than to rivers or wetlands. After irradiation equivalent to 1.7 days of natural solar radiation, DOC concentrations, on average, decreased by 38% and UV absorbance decreased by 25%. Irradiation decreased the relative abundances of terrestrial humic-like components and increased protein-like aspects of the DOM pool. These findings suggest that high internal production and/or prolonged exposure to sunlight exerts a distinct and significant influence on the chemistry of urban pond DOM, which likely reduces its chemical similarity with upstream sources. These properties of urban pond DOM may alter its biogeochemical role in these relatively novel aquatic ecosystems.
- MeSH
- ekosystém MeSH
- organické látky chemie MeSH
- rybníky chemie MeSH
- sladká voda MeSH
- uhlík chemie MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
elektronický časopis
- MeSH
- mikrobiologie MeSH
- Konspekt
- Mikrobiologie
- NLK Obory
- mikrobiologie, lékařská mikrobiologie
- NLK Publikační typ
- elektronické časopisy
Iron is present in all types of wastewater; however, besides acid mine drainage, where it is a major constituent of concern, it is usually neglected in other types of wastewaters. In all kinds of constructed wetlands, iron plays important role in removal of organics and phosphorus, and it has an impact on transformation of nitrogen, sulfur, and metals. The biogeochemistry of iron is well understood in natural wetlands, but knowledge about iron impact on microbiological and chemical transformations during wastewater treatment in constructed wetlands is very limited. So far, the sparse research in this area provides limited information on observed interactions with several varying parameters across the studies, making it difficult to draw fundamental and mechanistic conclusions. A critical review of the complex biogeochemical networking of iron in CWs is therefore necessary to fill the gap in knowledge on the role of iron and its biogeochemical multi-interactions in wastewater treatment processes of CWs. This review is the first with specific focus on iron, discussing its mitigation and retention in CWs with different configurations and operational strategies, and presenting both seasonal dynamics and the potential remobilization of Fe. It also comprehensively discusses the interactions of redox-controlled iron turnover with the biogeochemical processes of other elements, for example, carbon (C), nitrogen (N), phosphorus (P), sulfur (S), and heavy metals. The health response of wetland plants to both deficiency and toxicity of Fe in CWs designed with specific treatment targets has also been evaluated. Due to the complexity of various wastewater compositions and microredox gradients in the root rhizosphere in CWs, future research needs have also been identified.
- MeSH
- dusík MeSH
- mokřady * MeSH
- odpad tekutý - odstraňování MeSH
- odpadní voda * MeSH
- železo MeSH
- Publikační typ
- časopisecké články MeSH
- přehledy MeSH
