The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Noah Fierer - One of the best experts on this subject based on the ideXlab platform.
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Temporal Variability in soil microbial communities across land use types
The ISME Journal, 2013Co-Authors: Christian L Lauber, Jay T Lennon, Kelly S Ramirez, Zach Aanderud, Noah FiererAbstract:Although numerous studies have investigated changes in soil microbial communities across space, questions about the Temporal Variability in these communities and how this Variability compares across soils have received far less attention. We collected soils on a monthly basis (May to November) from replicated plots representing three land-use types (conventional and reduced-input row crop agricultural plots and early successional grasslands) maintained at a research site in Michigan, USA. Using barcoded pyrosequencing of the 16S rRNA gene, we found that the agricultural and early successional land uses harbored unique soil bacterial communities that exhibited distinct Temporal patterns. α-Diversity, the numbers of taxa or lineages, was significantly influenced by the sampling month with the Temporal Variability in α-diversity exceeding the Variability between land-use types. In contrast, differences in community composition across land-use types were reasonably constant across the 7-month period, suggesting that the time of sampling is less important when assessing β-diversity patterns. Communities in the agricultural soils were most variable over time and the changes were significantly correlated with soil moisture and temperature. Temporal shifts in bacterial community composition within the successional grassland plots were less predictable and are likely a product of complex interactions between the soil environment and the more diverse plant community. Temporal Variability needs to be carefully assessed when comparing microbial diversity across soil types and the Temporal patterns in microbial community structure can not necessarily be generalized across land uses, even if those soils are exposed to the same climatic conditions.
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Temporal Variability in the diversity and composition of stream bacterioplankton communities
Environmental Microbiology, 2012Co-Authors: M C Portillo, Suzanne P Anderson, Noah FiererAbstract:Summary Bacterioplankton in freshwater streams play a critical roleinstreamnutrientcycling.Despitetheirecological importance, the Temporal Variability in the structure of stream bacterioplankton communities remains under- studied. We investigated the composition and tempo- ral Variability of stream bacterial communities and the influence of physicochemical parameters on these communities. We used barcoded pyrosequencing to survey bacterial communities in 107 streamwater samples collected from four locations in the Colorado Rocky Mountains from September 2008 to November 2009. The four sampled locations harboured distinct communities yet, at each sampling location, there was pronounced Temporal Variability in both community composition and alpha diversity levels. These tempo- ral shifts in bacterioplankton community structure were not seasonal; rather, their diversity and compo- sitionappearedtobedrivenbyintermittentchangesin various streamwater biogeochemical conditions. Bac- terial communities varied independently of time, as indicated by the observation that communities in samples collected close together in time were no more similar than those collected months apart. The tempo- ral turnover in community composition was higher than observed in most previously studied microbial, plant or animal communities, highlighting the impor- tance of stochastic processes and disturbance events in structuring these communities over time. Detailed Temporal sampling is important if the objective is to monitormicrobialcommunitydynamicsinpulsedeco- systems like streams.
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short term Temporal Variability in airborne bacterial and fungal populations
Applied and Environmental Microbiology, 2008Co-Authors: Rob Knight, Noah Fierer, Zongzhi Liu, Mari Rodriguezhernandez, Matthew R Henn, Mark HernandezAbstract:Airborne microorganisms have been studied for centuries, but the majority of this research has relied on cultivation-dependent surveys that may not capture all of the microbial diversity in the atmosphere. As a result, our understanding of airborne microbial ecology is limited despite the relevance of airborne microbes to human health, various ecosystem functions, and environmental quality. Cultivation-independent surveys of small-subunit rRNA genes were conducted in order to identify the types of airborne bacteria and fungi found at a single site (Boulder, CO) and the Temporal Variability in the microbial assemblages over an 8-day period. We found that the air samples were dominated by ascomycete fungi of the Hypocreales order and a diverse array of bacteria, including members of the proteobacterial and Cytophaga-Flavobacterium-Bacteroides groups that are commonly found in comparable culture-independent surveys of airborne bacteria. Bacterium/fungus ratios varied by 2 orders of magnitude over the sampling period, and we observed large shifts in the phylogenetic diversity of bacteria present in the air samples collected on different dates, shifts that were not likely to be related to local meteorological conditions. We observed more phylogenetic similarity between bacteria collected from geographically distant sites than between bacteria collected from the same site on different days. These results suggest that outdoor air may harbor similar types of bacteria regardless of location and that the short-term Temporal Variability in airborne bacterial assemblages can be very large.
Ricardo Calado - One of the best experts on this subject based on the ideXlab platform.
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spatio Temporal Variability in the fatty acid profile of the adductor muscle of the common cockle cerastoderma edule and its relevance for tracing geographic origin
Food Control, 2017Co-Authors: Fernando Ricardo, Elisabete Maciel, Rosario M M Domingues, Ricardo CaladoAbstract:Abstract The present study aimed to identify the potential existence of spatio-Temporal Variability in the fatty acid (FA) profile of the adductor muscle (AM) of a commercially important bivalve, the common cockle Cerastoderma edule, and determine if such Variability can be used to trace their geographic origin post-harvesting. Common cockles were sampled in eight ecosystems along the coast of mainland Portugal, as well as in two different channels within one of those ecosystems over two consecutive years. Results showed significant differences in FA profiles among ecosystems, namely due to different levels of eicosapentaenoic acid (EPA; 20:5n-3), arachidonic acid (20:4n-6), ratio of polyunsaturated FA (PUFA) n-3/n-6, monounsaturated FA (MUFA; 18:1n-9 and 20:1n-9/11) and bacterial FA (15:0, 17:0 and 18:1n-7). FA profiles also displayed significant differences between two consecutive years in channels from the same ecosystem. Overall, while the FA profile displayed by the AM of C. edule can be successfully used to trace their geographic origin, the existence of Temporal Variability requires a periodical verification of FA signatures to identify potential shifts, namely when comparing specimens from the same ecosystem.
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spatio Temporal Variability of trace elements fingerprints in cockle cerastoderma edule shells and its relevance for tracing geographic origin
Scientific Reports, 2017Co-Authors: Fernando Ricardo, Tânia Pimentel, Luciana Genio, Ricardo CaladoAbstract:Understanding spatio-Temporal Variability of trace elements fingerprints (TEF) in bivalve shells is paramount to determine the discrimination power of this analytical approach and secure traceability along supply chains. Spatio-Temporal Variability of TEF was assessed in cockle (Cerastoderma edule) shells using inductively coupled plasma-mass spectrometry (ICP-MS). Four elemental ratios (Mg/Ca, Mn/Ca, Sr/Ca and Ba/Ca) were measured from the shells of specimens originating from eight different ecosystems along the Portuguese coast, as well as from four different areas, within one of them, over two consecutive years (2013 and 2014). TEF varied significantly in the shells of bivalves originating from the eight ecosystems surveyed in the present study. Linear discriminant function analyses assigned sampled cockles to each of the eight ecosystems with an average accuracy of 90%. Elemental ratios also displayed significant differences between the two consecutive years in the four areas monitored in the same ecosystem. Overall, while TEF displayed by cockle shells can be successfully used to trace their geographic origin, a periodical verification of TEF (>6 months and <1 year) is required to control for Temporal Variability whenever comparing specimens originating from the same area collected more than six months apart.
Fernando Ricardo - One of the best experts on this subject based on the ideXlab platform.
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spatio Temporal Variability in the fatty acid profile of the adductor muscle of the common cockle cerastoderma edule and its relevance for tracing geographic origin
Food Control, 2017Co-Authors: Fernando Ricardo, Elisabete Maciel, Rosario M M Domingues, Ricardo CaladoAbstract:Abstract The present study aimed to identify the potential existence of spatio-Temporal Variability in the fatty acid (FA) profile of the adductor muscle (AM) of a commercially important bivalve, the common cockle Cerastoderma edule, and determine if such Variability can be used to trace their geographic origin post-harvesting. Common cockles were sampled in eight ecosystems along the coast of mainland Portugal, as well as in two different channels within one of those ecosystems over two consecutive years. Results showed significant differences in FA profiles among ecosystems, namely due to different levels of eicosapentaenoic acid (EPA; 20:5n-3), arachidonic acid (20:4n-6), ratio of polyunsaturated FA (PUFA) n-3/n-6, monounsaturated FA (MUFA; 18:1n-9 and 20:1n-9/11) and bacterial FA (15:0, 17:0 and 18:1n-7). FA profiles also displayed significant differences between two consecutive years in channels from the same ecosystem. Overall, while the FA profile displayed by the AM of C. edule can be successfully used to trace their geographic origin, the existence of Temporal Variability requires a periodical verification of FA signatures to identify potential shifts, namely when comparing specimens from the same ecosystem.
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spatio Temporal Variability of trace elements fingerprints in cockle cerastoderma edule shells and its relevance for tracing geographic origin
Scientific Reports, 2017Co-Authors: Fernando Ricardo, Tânia Pimentel, Luciana Genio, Ricardo CaladoAbstract:Understanding spatio-Temporal Variability of trace elements fingerprints (TEF) in bivalve shells is paramount to determine the discrimination power of this analytical approach and secure traceability along supply chains. Spatio-Temporal Variability of TEF was assessed in cockle (Cerastoderma edule) shells using inductively coupled plasma-mass spectrometry (ICP-MS). Four elemental ratios (Mg/Ca, Mn/Ca, Sr/Ca and Ba/Ca) were measured from the shells of specimens originating from eight different ecosystems along the Portuguese coast, as well as from four different areas, within one of them, over two consecutive years (2013 and 2014). TEF varied significantly in the shells of bivalves originating from the eight ecosystems surveyed in the present study. Linear discriminant function analyses assigned sampled cockles to each of the eight ecosystems with an average accuracy of 90%. Elemental ratios also displayed significant differences between the two consecutive years in the four areas monitored in the same ecosystem. Overall, while TEF displayed by cockle shells can be successfully used to trace their geographic origin, a periodical verification of TEF (>6 months and <1 year) is required to control for Temporal Variability whenever comparing specimens originating from the same area collected more than six months apart.
Renato Morbidelli - One of the best experts on this subject based on the ideXlab platform.
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catchment scale soil moisture spatial Temporal Variability
Journal of Hydrology, 2012Co-Authors: Luca Brocca, T Tullo, Florisa Melone, Tommaso Moramarco, Renato MorbidelliAbstract:Summary The characterization of the spatial–Temporal Variability of soil moisture is of paramount importance in many scientific fields and operational applications. However, due to the high Variability of soil moisture, its monitoring over large areas and for extended periods through in situ point measurements is not straightforward. Usually, in the scientific literature, soil moisture Variability has been investigated over short periods and in large areas or over long periods but in small areas. In this study, an effort to understanding soil moisture Variability at catchment scale (>100 km 2 ), which is the size needed for some hydrological applications and for remote sensing validation analysis, is done. Specifically, measurements were carried out in two adjacent areas located in central Italy with extension of 178 and 242 km 2 and over a period of 1 year (35 sampling days) with almost weekly frequency except for the summer period because of soil hardness. For each area, 46 sites were monitored and, for each site, 3 measurements were performed to obtain reliable soil moisture estimates. Soil moisture was measured with a portable Time Domain Reflectometer for a layer depth of 0–15 cm. A statistical and Temporal stability analysis is employed to assess the space–time Variability of soil moisture at local and catchment scale. Moreover, by comparing the results with those obtained in previous studies conducted in the same study area, a synthesis of soil moisture Variability for a range of spatial scales, from few square meters to several square kilometers, is attempted. For the investigated area, the two main findings inferred are: (1) the spatial Variability of soil moisture increases with the area up to ∼10 km 2 and then remains quite constant with an average coefficient of variation equal to ∼0.20; (2) regardless of the areal extension, the soil moisture exhibits Temporal stability features and, hence, few measurements can be used to infer areal mean values with a good accuracy (determination coefficient higher than 0.88). These insights based on in situ soil moisture observations corroborate the opportunity to use point information for the validation of coarse resolution satellite images. Moreover, the feasibility to use coarse resolution data for hydrological applications in small to medium sized catchments is confirmed.
P.w. Kelley-hauske - One of the best experts on this subject based on the ideXlab platform.
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Temporal Variability of stemflow volume in a beech-yellow poplar forest in relation to tree species and size
Journal of Hydrology, 2010Co-Authors: Delphis F Levia, J.t. Van Stan, Susanna M. Mage, P.w. Kelley-hauskeAbstract:Summary Stemflow has distinguishable effects on the hydrology and biogeochemistry of wooded ecosystems. Nonetheless, it is a relatively poorly understood hydrologic process. No known studies have investigated the Temporal Variability of stemflow volume at 5-min intervals in a beech-yellow poplar forest of eastern North America. The aim of this research is to compare the Temporal Variability of stemflow generation by Fagus grandifolia Ehrh. (American beech) and Liriodendron tulipifera L. (yellow poplar) in relation to tree species and size. Employing a dense network of tipping-bucket stemflow gages interfaced with a datalogger, a 5 min stemflow yield database was assembled and analyzed to better discern how stemflow production varies (Temporally) with tree species and size. Results indicate that both tree species and size have detectable effects on the Temporal Variability of stemflow yield. Observational data, scientific analysis, and correspondence analysis reveals that stemflow yield: (1) is more similar within than between the two tree species with differences likely being attributable to differences in bark texture and water storage capacity; (2) tree size affects stemflow yield within species; (3) rain event characteristics affect stemflow yield; and (4) stemflow yield for particular trees and rain events is the result of a complex set of interactions among tree species, tree size, and meteorological conditions. These results suggest that the Temporal variation in stemflow yield from co-occurring forest trees may play a significant role in subsurface drainage of wooded ecosystems during rain events.
