Impact of long-term experimental water level drawdown on vegetation and carbon gas dynamics of boreal mire ecosystems

2020 ◽  
Author(s):  
Eeva-Stiina Tuittila ◽  
Aino Korrensalo ◽  
Anna Laine ◽  
Nicola Kokkonen ◽  
Lauri Mehtätalo ◽  
...  
Keyword(s):  
Water Level ◽  
Gas Dynamics ◽  
Experimental Studies ◽  
Net Ecosystem Exchange ◽  
Woody Species ◽  
Long Term Results ◽  
Moss Species ◽  
Poor Fen ◽  
The Impact

<p>Recent paleoecological studies have demonstrated an ongoing drying trend in temperate and boreal peatlands in Europe and in Canada. This drying is likely to alter vegetation and carbon gas exchange with atmosphere. However, to revel the expected change in carbon gas dynamics associated with decrease in water level experimental studies and long-term monitoring are needed. In here we present results from long term experiment in Finland where the impact of water level drawdown (WLD) of ~10 cm on three different peatland sites, two fens and a bog, has been studied since year 2000.</p><p> </p><p>Response to WLD differed between the three ecosystem types. In the nutrient rich fen WLD initiated rapid directional succession from sedge dominated system to the dominance of woody species. In the poor fen changes were less drastic: Initially WLD benefitted dwarf scrubs already present at the site, later they were overtaken by pines.  Sedges as a group hold their position but Carex species were replaced by Eriophorum. Similarly to sedges, in the moss layer proportions of different Sphagnum moss species changed. Bog vegetation was more stable than fen vegetation.</p><p> </p><p>In all the ecosystems methane emissions decreased directly after WLD. In contrast, the response of CO2 dynamics was more complex. While long term net ecosystem exchange decreased to lower level than in controls in all studied ecosystems, the response of photosynthesis and respiration differed between the three ecosystems and between short term and long term. Results show how the response of peatlands to climate change is diverse and emphasize the need to understand what factors regulate the stability and resilience of peatland functioning.</p>

scholarly journals Assessing Stream-Aquifer Connectivity in a Coastal California Watershed

Water ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 416
Author(s):  
Bwalya Malama ◽  
Devin Pritchard-Peterson ◽  
John J. Jasbinsek ◽  
Christopher Surfleet
Keyword(s):  
Time Series ◽  
Spectral Analysis ◽  
Water Level ◽  
Time Series Data ◽  
Series Data ◽  
Low Permeability ◽  
Pumping Tests ◽  
Stream Flows ◽  
The Impact

We report the results of field and laboratory investigations of stream-aquifer interactions in a watershed along the California coast to assess the impact of groundwater pumping for irrigation on stream flows. The methods used include subsurface sediment sampling using direct-push drilling, laboratory permeability and particle size analyses of sediment, piezometer installation and instrumentation, stream discharge and stage monitoring, pumping tests for aquifer characterization, resistivity surveys, and long-term passive monitoring of stream stage and groundwater levels. Spectral analysis of long-term water level data was used to assess correlation between stream and groundwater level time series data. The investigations revealed the presence of a thin low permeability silt-clay aquitard unit between the main aquifer and the stream. This suggested a three layer conceptual model of the subsurface comprising unconfined and confined aquifers separated by an aquitard layer. This was broadly confirmed by resistivity surveys and pumping tests, the latter of which indicated the occurrence of leakage across the aquitard. The aquitard was determined to be 2–3 orders of magnitude less permeable than the aquifer, which is indicative of weak stream-aquifer connectivity and was confirmed by spectral analysis of stream-aquifer water level time series. The results illustrate the importance of site-specific investigations and suggest that even in systems where the stream is not in direct hydraulic contact with the producing aquifer, long-term stream depletion can occur due to leakage across low permeability units. This has implications for management of stream flows, groundwater abstraction, and water resources management during prolonged periods of drought.

scholarly journals The Multiscale Monitoring of Peatland Ecosystem Carbon Cycling in the Middle Taiga Zone of Western Siberia: The Mukhrino Bog Case Study

Land ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 824
Author(s):  
Egor Dyukarev ◽  
Evgeny Zarov ◽  
Pavel Alekseychik ◽  
Jelmer Nijp ◽  
Nina Filippova ◽  
...  
Keyword(s):  
Carbon Cycling ◽  
Western Siberia ◽  
Carbon Accumulation ◽  
Middle Taiga ◽  
Taiga Zone ◽  
Field Station ◽  
Moss Species ◽  
Chamber Method ◽  
The Impact

The peatlands of the West Siberian Lowlands, comprising the largest pristine peatland area of the world, have not previously been covered by continuous measurement and monitoring programs. The response of peatlands to climate change occurs over several decades. This paper summarizes the results of peatland carbon balance studies collected over ten years at the Mukhrino field station (Mukhrino FS, MFS) operating in the Middle Taiga Zone of Western Siberia. A multiscale approach was applied for the investigations of peatland carbon cycling. Carbon dioxide fluxes at the local scale studied using the chamber method showed net accumulation with rates from 110, to 57.8 gC m−2 at the Sphagnum hollow site. Net CO2 fluxes at the pine-dwarf shrubs-Sphagnum ridge varied from negative (−32.1 gC m−2 in 2019) to positive (13.4 gC m−2 in 2017). The cumulative May-August net ecosystem exchange (NEE) from eddy-covariance (EC) measurements at the ecosystem scale was −202 gC m−2 in 2015, due to the impact of photosynthesis of pine trees which was not registered by the chamber method. The net annual accumulation of carbon in the live part of mosses was estimated at 24–190 gC m−2 depending on the Sphagnum moss species. Long-term carbon accumulation rates obtained by radiocarbon analysis ranged from 28.5 to 57.2 gC m−2 yr−1, with local extremes of up to 176.2 gC m−2 yr−1. The obtained estimates of various carbon fluxes using EC and chamber methods, the accounting for Sphagnum growth and decomposition, and long-term peat accumulation provided information about the functioning of the peatland ecosystems at different spatial and temporal scales. Multiscale carbon flux monitoring reveals useful new information for forecasting the response of northern peatland carbon cycles to climatic changes.

scholarly journals D2 Lymphadenectomy for Gastric Adenocarcinoma: Long-term Results and the Impact of Surgeon Experience on the Survival Rates

Chirurgia ◽  
2018 ◽  
Vol 113 (6) ◽  
pp. 772
Author(s):  
Stefan Tudor ◽  
Traian Dumitrascu ◽  
Mircea Manuc ◽  
Bogdan Trandafir ◽  
Mihnea Ionescu ◽  
...  
Keyword(s):  
Gastric Adenocarcinoma ◽  
Survival Rates ◽  
Long Term Results ◽  
D2 Lymphadenectomy ◽  
Surgeon Experience ◽  
The Impact

scholarly journals Librarian-Teacher Partnerships for Inquiry Learning: Measures of Effectiveness for a Practice-Based Model of Professional Development

2009 ◽  
Vol 4 (2) ◽  
pp. 97 ◽  
Author(s):  
Joyce Yukawa ◽  
Violet H. Harada
Keyword(s):  
Professional Development ◽  
Student Performance ◽  
Course Design ◽  
Discussion Board ◽  
Long Term Results ◽  
School Site ◽  
Development Team ◽  
K 12 ◽  
The Impact

Objective – This study analyzed the effects of a practice-based model of professional development on the teaching and collaborative practices of 9 teams of librarians and teachers, who created and implemented units of inquiry-focused study with K-12 students during a yearlong course. The authors describe how the collection and analysis of evidence guided the development team in the formative and summative evaluations of the outcomes of the professional development, as well as the long-term results of participation in this initiative. Methods – The authors used an interpretive, participative approach. The first author was the external reviewer for the project; the second author headed the development team and served as a participant-observer. Triangulated data were collected from participants in the form of learning logs, discussion board postings, interviews, questionnaires, and learning portfolios consisting of unit and lesson plans and student work samples with critiques. Data were also collected from the professional development designers in the form of meeting notes, responses to participants, interviews, and course documents. For two years following the end of the formal course, the authors also conducted follow-up email correspondence with all teams and site visits with six teams to determine sustained or expanded implementation of inquiry-focused, collaborative curriculum development. Results – The practice-based approach to professional development required continual modification of the course design and timely, individualized mentoring and feedback, based on analysis and co-reflection by the developers on the evidence gathered through participant logs, reports, and school site visits. Modeling the inquiry process in their own course development work and making this process transparent to the participating community were essential to improvement. Course participants reported beneficial results in both immediate and long-term changes in practice. The summative evaluation identified significant changes in practice in three areas: (1) the design of inquiry-focused learning, (2) the roles of the teacher and librarian in collaborative development of instruction, and (3) the impact on student performance. Two years after the yearlong professional development course, most participants indicated that they continued to incorporate inquiry-based approaches, and over half of the participants were involving other colleagues at their schools in inquiry-focused practices. Six of the librarians assumed major curricular roles in their respective schools. Conclusion – The practice-based model of professional development appears to be effective and sustainable. It has been tested and modified by other development teams in the last two years. More extensive use of the model in other contexts with further testing and refinement by other developers is needed to ensure that the model is robust and widely applicable.

scholarly journals The impact of the loco-regional treatment in elderly breast cancer patients: Hypo-fractionated exclusive radiotherapy, single institution long-term results

The Breast ◽  
2010 ◽  
Vol 19 (5) ◽  
pp. 413-416 ◽  
Author(s):  
Cyrus Chargari ◽  
Youlia M. Kirova ◽  
Fatima Laki ◽  
Alexia Savignoni ◽  
Thierry Dorval ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Cancer Patients ◽  
Long Term Results ◽  
Breast Cancer Patients ◽  
Single Institution ◽  
The Impact ◽  
Regional Treatment

Photodynamic and microcurrent therapy in complex treatment of patients with generalized periodontitis

2016 ◽  
Vol 15 (6) ◽  
pp. 289-293
Author(s):  
M. Yu Gerasimenko ◽  
Nina Nikolaevna Lazarenko ◽  
M. A Amkhadova ◽  
S. N Smirnova ◽  
O. V Trunova ◽  
...  
Keyword(s):  
Photodynamic Therapy ◽  
Electrical Stimulation ◽  
Chronic Periodontitis ◽  
Cerebral Hemodynamics ◽  
Long Term Results ◽  
Complex Treatment ◽  
Autonomic Balance ◽  
The Impact

The results of the complex treatment of patients with generalized chronic periodontitis, including photodynamic therapy and microcurrent electrical stimulation are presented. Analysis of the immediate and long-term results showed the effectiveness of the impact of this treatment on cerebral hemodynamics and autonomic balance in these patients.

The impact of advanced age on short- and long-term results after surgery for colorectal cancer

2015 ◽  
Vol 47 (6) ◽  
pp. 331-336 ◽  
Author(s):  
A. Dinnewitzer ◽  
C. Nawara ◽  
C. Augschöll ◽  
D. Neureiter ◽  
W. Hitzl ◽  
...  
Keyword(s):  
Colorectal Cancer ◽  
Advanced Age ◽  
Long Term Results ◽  
Short And Long Term ◽  
The Impact

scholarly journals Plasmodium falciparum schizont stage transcriptome variation among clinical isolates and laboratory-adapted clones

2018 ◽  
Author(s):  
Sarah J Tarr ◽  
Ofelia Díaz-Ingelmo ◽  
Lindsay B Stewart ◽  
Suzanne E Hocking ◽  
Lee Murray ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Vaccine Development ◽  
Ex Vivo ◽  
Experimental Studies ◽  
Differentially Expressed ◽  
Clinical Isolates ◽  
Schizont Stage ◽  
Variable Expression ◽  
The Impact

AbstractMalaria parasite genes exhibit variation in both sequence and expression level. There is much information on sequence polymorphism, but less resolution on natural variation in transcriptomes of parasites at specific developmental stages. This is largely because it is challenging to obtain highly replicated sampling of transcriptomes to overcome potentially confounding technical and biological variation. We address the issue in the major human parasite Plasmodium falciparum by obtaining RNA-seq profiles of multiple independent replicate preparations of mature schizont-stage parasites from a panel of clinical isolates recently established in culture and from long-term laboratory-adapted clones. With a goal of robustly identifying variably expressed genes, we show that increasing the numbers of biological sample replicates greatly improves the discovery rate. Generally, six independent replicates of each parasite culture is recommendable as being significantly to lower numbers, although for highly expressed genes variable expression can be detected when fewer replicates are available. A broad comparison identifies genes differing in relative expression between cultured clinical isolates and laboratory-adapted clones. Genes more highly expressed in the laboratory-adapted clones include an AP2 transcription factor gene Pf3D7_0420300 and putative methyl transferase genes. The variable expression of several known merozoite invasion ligands is confirmed, and previously uncharacterised genes are shown to be differentially expressed among clinical isolates. New RT-qPCR assays validate the variation in transcript levels of these genes, and allow quantitation of expression to be extended to a wider panel of clinical isolate samples. These variably expressed genes are new candidates for investigation as potential determinants of alternative parasite developmental pathways or targets of immunity.Author summaryUnderstanding parasite diversity and adaptation may require characterisation of gene expression variation, and is vital if chemotherapeutic or vaccine development is to consider new candidate targets, but it is technically challenging to generate precise data on clinical isolates. Here, we analyse the transcriptomes of mature Plasmodium falciparum schizonts using RNA-sequencing, using large numbers of biological replicate samples to minimise the impact of inter-replicate variation on observed patterns of differential expression. This identifies genes that are differentially expressed in long term laboratory-adapted parasites and recently cultured clinical isolates, as well as among different clinical isolates. In additional samples of schizonts grown in the first cycle ex vivo prior to any erythrocyte invasion, expression levels of a selected panel of these genes vary among isolates, but mean levels are similar to those in the continuously cultured clinical isolates, indicating that the latter are useful for experimental studies requiring biological replication.

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