10 research outputs found
Linking microbial communities, functional genes and nitrogen-cycling processes in forest floors under four tree species
TRY plant trait database â enhanced coverage and open access
Plant traits - the morphological, anatomical, physiological, biochemical and phenological characteristics of plants - determine how plants respond to environmental factors, affect other trophic levels, and influence ecosystem properties and their benefits and detriments to people. Plant trait data thus represent the basis for a vast area of research spanning from evolutionary biology, community and functional ecology, to biodiversity conservation, ecosystem and landscape management, restoration, biogeography and earth system modelling. Since its foundation in 2007, the TRY database of plant traits has grown continuously. It now provides unprecedented data coverage under an open access data policy and is the main plant trait database used by the research community worldwide. Increasingly, the TRY database also supports new frontiers of traitâbased plant research, including the identification of data gaps and the subsequent mobilization or measurement of new data. To support this development, in this article we evaluate the extent of the trait data compiled in TRY and analyse emerging patterns of data coverage and representativeness. Best species coverage is achieved for categorical traits - almost complete coverage for âplant growth formâ. However, most traits relevant for ecology and vegetation modelling are characterized by continuous intraspecific variation and traitâenvironmental relationships. These traits have to be measured on individual plants in their respective environment. Despite unprecedented data coverage, we observe a humbling lack of completeness and representativeness of these continuous traits in many aspects. We, therefore, conclude that reducing data gaps and biases in the TRY database remains a key challenge and requires a coordinated approach to data mobilization and trait measurements. This can only be achieved in collaboration with other initiatives
Nitrogen cycling processes and microbial communities in reconstructed oil-sands soils
Covering 140,200 square km, the Athabasca Oil Sands deposit in Alberta is one of the largest single oil deposits in the world. Following surface mining, companies are required to restore soil-like profiles that can support the previous land capabilities. The overall objective of this thesis was to measure, compare and understand processes underlying nitrogen cycling rates and microbial communities in 20- to 30- year-old reconstructed oil-sands soils and in natural boreal-forest soils. The use of Âčâ”N tracer methods in combination with massively parallel sequencing techniques of the 16S and ITS genes identified key dissimilarities between reconstructed and natural boreal-forest soils. In reconstructed soils, NHââș was mainly cycled through the recalcitrant organic-N pool. In natural soils, NHââș was produced from the recalcitrant organic-N pool, but predominantly consumed in the labile organic-N pool, suggesting greater prominence of microbial N-cycling activity in the natural soils compared to the reconstructed soils. Reconstructed soils also produced more NOâ- than they immobilized it resulting in net nitrification rates. Prokaryotic and fungal ÎČ-diversity, but not α-diversity, differed between reconstructed and natural forest soils. Microorganisms associated with a copiotrophic lifestyle were more abundant in reconstructed soils, whereas microorganisms associated with an oligotrophic lifestyle were more abundant in natural forest soils. Vegetation cover was the main factor influencing prokaryotic and fungal α-diversity in reconstructed and natural forest soils. Nitrogen deposition, pH, soil nutrient content and plant cover influenced prokaryotic and fungal ÎČ-diversity. The results of this thesis deepen our understanding of the distinct pedological environments of oil-sands reconstructed soils and highlighted the importance of above- and below-ground interactions in reconstructed and natural ecosystems.Forestry, Faculty ofGraduat
Contenu total en éléments traces de sols forestiers du Québec méridional
Les sols forestiers constituent un rĂ©servoir considĂ©rable dâĂ©lĂ©ments nutritifs disponibles pour soutenir la productivitĂ© forestiĂšre. Ces sols contiennent aussi une quantitĂ©, encore inconnue Ă ce jour, dâĂ©lĂ©ments traces biodisponibles provenant de sources anthropiques ou naturelles. Or, plusieurs de ces Ă©lĂ©ments recĂšlent un potentiel toxique pour les organismes vivants. Ainsi, la quantification de la concentration et du contenu total en Ă©lĂ©ments traces des sols forestiers sâavĂšre nĂ©cessaire afin dâĂ©valuer les impacts des perturbations sur la qualitĂ© des sols.
Les objectifs de ce projet de recherche sont: 1) de mesurer le contenu total en Ă©lĂ©ments traces en phase solide (Ag, As, Ba, Cd, Ce, Co, Cr, Cu, Mn, Ni, Pb, Rb, Se, Sr, Tl, V, Y, Zn) des divers horizons de sols dâĂ©cosystĂšmes forestiers du QuĂ©bec mĂ©ridional; 2) dâĂ©tablir des liens significatifs entre la fraction soluble dans lâeau des Ă©lĂ©ments traces et les propriĂ©tĂ©s des horizons de sols et; 3) dâĂ©valuer le rĂŽle de la proximitĂ© dâun centre urbain sur les contenus en Ă©lĂ©ments traces. Pour rĂ©pondre Ă ces objectifs, quatre profils de sols situĂ©s dans la rĂ©gion de St-Hippolyte et deux situĂ©s dans la rĂ©gion de MontrĂ©al furent Ă©chantillonnĂ©s jusqu'Ă l'atteinte du matĂ©riel parental.
Les rĂ©sultats de ce projet de recherche ont rĂ©vĂ©lĂ© que le contenu total en Ă©lĂ©ments traces prĂ©sents dans les profils de sols se retrouve en grande partie dans les fragments grossiers du sol. Il a Ă©tĂ© dĂ©montrĂ© que la teneur en carbone organique, les complexes organomĂ©talliques et les oxydes de fer et dâaluminium dictent la distribution en profil de la majoritĂ© des Ă©lĂ©ments traces Ă©tudiĂ©s. Finalement, il fut prouvĂ© que la rĂ©gion de MontrĂ©al prĂ©sente des niveaux de contamination en Ă©lĂ©ments traces (Ag, As, Ba, Cu, Mn, Pb, Rb, Se, Sr, Tl et Zn) supĂ©rieurs Ă ceux rencontrĂ©s dans les Laurentides.Forest soils represent an important stock of nutrients available to sustain forest productivity. They also contain an amount, still unknown, of trace elements inherited from natural or anthropogical sources. Many of these trace elements can be toxic to living organisms. Thereby, quantification of the concentration and the total content of trace elements in forest soils is necessary to asses the impact of these elements on soil quality.
The specific objectives of this research project are: 1) to measure the total content of trace elements in solid phase (Ag, As, Ba, Cd, Ce, Co, Cr, Cu, Mn, Ni, Pb, Rb, Se, Sr, Tl, V, Y, Zn) of various soil horizons in two forest ecosystems of southern Quebec, 2) to establish significant correlations between the bioavailable fraction (water-soluble) of trace elements and soil horizons properties and 3) to compare the trace element stock of two Canadian Shieldâs forest soil with those of similar soils situated in the Montreal area. To achieve these goals four soil profiles situated in the pristine region of St-Hippolyte and two in the urban area of MontrĂ©al, were excavated down to the parent material.
The results of this research have established that the trace elementâs total stock is mainly concentrated in coarse fragments of the soil. Multivariate statistical analyses revealed significant links between organic carbon, organometallic complexes as well as Fe-Al oxides and the distribution of trace element in soil profiles. Finally, it was proved that Montrealâs soil contained more trace element (Ag, As, Ba, Cu, Mn, Pb, Rb, Se, Sr, Tl et Zn) than Canadian Shieldâs soils
Inoculation with Rhizophagus irregularis Does Not Alter Arbuscular Mycorrhizal Fungal Community Structure within the Roots of Corn, Wheat, and Soybean Crops
Little is known about establishment success of the arbuscular mycorrhizal fungal (AMF) inocula and their effects on a soil-indigenous community of AMF. In this study, we assessed the effect of introducing Rhizophagus irregularis DAOM-197198 in soil under field condition on the community composition of indigenous AMF in the roots of corn (Zea mays), soybean (Glycine max), and wheat (Triticum aestivum). Three field trials were conducted with inoculated and non-inoculated plots. Four to ten roots and their rhizosphere soil samples of two growth stages for corn and wheat, and one growing stage of soybean, were collected, totalling 122 root and soil samples. Root colonization was measured microscopically, and the fungal communities were determined by paired-end Illumina MiSeq amplicon sequencing using 18S rDNA marker. After quality trimming and merging of paired ends, 6.7 million sequences could be assigned to 414 different operational taxonomic units. These could be assigned to 68 virtual taxa (VT) using the AMF reference sequence database MaarjAM. The most abundant VT corresponded to R. irregularis. The inoculation treatment did not influence the presence of R. irregularis, or AMF community diversity in roots. This seems to indicate that inoculation with R. irregularis DAOM-197198 does not change the indigenous AMF community composition, probably because it is already present in high abundance naturally
Profiling Undergraduate Soil Science Education in Canada: Status and Projected Trends
Global declines in postsecondary enrollment in soil science programs over the last several decades have been mainly attributed to an overemphasis on the connection with agronomy and production agriculture but recent enrollment increases in the United States suggest change is afoot. To determine if similar trends are occurring in Canada, we inventoried undergraduate soil science course offerings at postsecondary institutions and conducted a survey to assess the status and projected trends in soil science education. We found that 64% of universities and 37% of colleges offer undergraduate soil science courses as part of degrees or diplomas where knowledge of soil science is important (e.g., agriculture, resource management). In Canada there are 149 undergraduate soil science courses taught in universities and 58 at colleges. On average, there are 3.2 courses taught at each university and 1.9 at each college that offer soil science courses. Soil science programs at the University of British Columbia, University of Saskatchewan, and University of Manitoba offer between 8 and 9 soil science courses and represent 17.4% of the national total. Enrollments in all courses across the country are projected to be steady with some anticipated growth, trends that are consistent with those reported in the United States and the Netherlands.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author
Identifying learning outcomes for a Canadian pedology field school: addressing the gap between new graduatesâ skills and the needs of the current job market
To address concerns among members of the Canadian Society of Soil Science (CSSS) regarding the disciplineâs capacity to train new soil professionals, specifically in pedology and field skills, members of the CSSSâs soil education and pedology committees have proposed to develop a pedology field school. To aid in the selection of learning outcomes that are relevant to professional practice, an online survey was sent to Canadian soil professionals within private industry and governmental organizations. Professional feedback was also requested regarding the creation of a web-based national soil education resource, and the certification of soil pedological skills. According to the survey results, the quality of new graduatesâ pedology and field skills was perceived as poor. Certain soil field skills and knowledge were thought to be either completely absent from the current Canadian curriculum (e.g. spatial variability of soil processes), or not well mastered by graduates (e.g. interpreting soil survey reports). Important learning outcomes were identified, such as: interpreting soil survey information, soil mapping, and soil-landscape classification with soil description/classification and soil genesis content needed as a refresher. Taking into consideration existing regional field schools, we recommend that the CSSS co-creates, where needed, and coordinate, where they already exist, regional pedology field schools throughout Canada. We also propose that CSSS develop a national pedology certification, and a web-based soil education resource. Also, further study is necessary to shed light on the contribution of non-disciplinary graduates to the professional practice and the impact this has on the perception of soil education in Canada.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author
Soil trace element changes during a phytoremediation trial with willows in southern Québec, Canada
Linking microbial communities, functional genes and nitrogen-cycling processes in forest floors under four tree species
TRY plant trait database - enhanced coverage and open access
10.1111/gcb.14904GLOBAL CHANGE BIOLOGY261119-18