Fate of Allochthonous Dissolved Organic Carbon in Lakes: A Quantitative Approach

Inputs of dissolved organic carbon (DOC) to lakes derived from the surrounding landscape can be stored, mineralized or passed to downstream ecosystems. The balance among these OC fates depends on a suite of physical, chemical, and biological processes within the lake, as well as the degree of recalcintrance of the allochthonous DOC load. The relative importance of these processes has not been well quantified due to the complex nature of lakes, as well as challenges in scaling DOC degradation experiments under controlled conditions to the whole lake scale. We used a coupled hydrodynamic-water quality model to simulate broad ranges in lake area and DOC, two characteristics important to processing allochthonous carbon through their influences on lake temperature, mixing depth and hydrology. We calibrated the model to four lakes from the North Temperate Lakes Long Term Ecological Research site, and simulated an additional 12 ‘hypothetical’ lakes to fill the gradients in lake size and DOC concentration. For each lake, we tested several mineralization rates (range: 0.001 d−1 to 0.010 d−1) representative of the range found in the literature. We found that mineralization rates at the ecosystem scale were roughly half the values from laboratory experiments, due to relatively cool water temperatures and other lake-specific factors that influence water temperature and hydrologic residence time. Results from simulations indicated that the fate of allochthonous DOC was controlled primarily by the mineralization rate and the hydrologic residence time. Lakes with residence times <1 year exported approximately 60% of the DOC, whereas lakes with residence times >6 years mineralized approximately 60% of the DOC. DOC fate in lakes can be determined with a few relatively easily measured factors, such as lake morphometry, residence time, and temperature, assuming we know the recalcitrance of the DOC

Lake eutrophication and its implications for organic carbon sequestration in Europe

The eutrophication of lowland lakes in Europe by excess nitrogen (N) and phosphorus (P) is severe because of the long history of land-cover change and agricultural intensification. The ecological and socio-economic effects of eutrophication are well understood but its effect on organic carbon (OC) sequestration by lakes and its change overtime has not been determined. Here, we compile data from ~90 culturally impacted European lakes [~60% are eutrophic, Total P (TP) >30 μg P l] and determine the extent to which OC burial rates have increased over the past 100-150 years. The average focussing corrected, OC accumulation rate (C AR) for the period 1950-1990 was ~60 g C m yr, and for lakes with >100 μg TP l the average was ~100 g C m yr. The ratio of post-1950 to 1900-1950 C AR is low (~1.5) indicating that C accumulation rates have been high throughout the 20th century. Compared to background estimates of OC burial (~5-10 g C m yr), contemporary rates have increased by at least four to fivefold. The statistical relationship between C AR and TP derived from this study (r = 0.5) can be used to estimate OC burial at sites lacking estimates of sediment C-burial. The implications of eutrophication, diagenesis, lake morphometry and sediment focussing as controls of OC burial rates are considered. A conservative interpretation of the results of the this study suggests that lowland European meso- to eutrophic lakes with >30 μg TP l had OC burial rates in excess of 50 g C m yr over the past century, indicating that previous estimates of regional lake OC burial have seriously underestimated their contribution to European carbon sequestration. Enhanced OC burial by lakes is one positive side-effect of the otherwise negative impact of the anthropogenic disruption of nutrient cycles. © 2014 John Wiley & Sons Ltd

Ett svårt arbete. Andlig omvårdnad som en del av sjuksköterskans ansvarsområde

En holistisk människosyn omfattar även att den andliga dimensionen inom omvårdnad beaktas. I sjuksköterskans kompetensområde ingår således att utöva andlig omvårdnad. Med syftet att undersöka sjuksköterskans attityder till en andlig aspekt av omvårdnad, vilka hinder som finns för att utöva detta och vilka vårdhandlingar som kan tänkas ingå inom detta fält har en litteraturstudie genomförts. Litteraturstudien omfattade 13 vetenskapliga artiklar. Data analyserades genom att använda en metod inspirerad av Graneheim & Lundmans innehållsanalys. Resultatet presenterades uppdelat under tre områden: attityder, hinder samt vårdhandlingar. Under resultatanalysen framkom underkategorier: sjuksköterskans egen andlighet, känsla av otillräcklighet, hinder i organisationen, förhållningssätt, bedömning, stöd, samtal, relation, närstående, samordning samt praktiska åtgärder. Resultatet tyder på att sjuksköterskan är positivt inställd till andlig omvårdnad men upplever den svår att utföra. Hinder som nämndes var brister i sjuksköterskans utbildning, sjuksköterskans egen andlighet samt tidsbrist. Den vårdhandling som nämndes flest gånger var att hänvisa till präst, pastor eller annan andlig ledare. Sjuksköterskan utövade även andlig omvårdnad genom samtal och bön. För att stötta hjälpte sjuksköterskan patienten att finna mening, tröstade samt underlättade patientens andliga utövande. Det fanns delade meningar angående kompetensen att utöva andlig omvårdnad. Det framkom att utbildning har ett värde, men också att erfarenhet var det väsentliga. Troligtvis har båda betydelse. Då studier i ämnet företrädesvis gjorts i andra länder och att man i Sverige endast har påbörjat dessa, behövs mer forskning inom andlig omvårdnad göras i Sverige. SÖKORD: Spiritual care, nursing, attitudes, spiritua

Object detection using deep learning : Making a detailed map from trained neural models

This study examines if it is possible to use pretrained neural models to make a detailed map in a set of case studies in Sweden. The models are taken from ESRI Living Atlas and are trained with data from the USA. The models are given orthophotos as input from three different parts of Sweden to make predictions from. The model results are combined to extract the best predictions of the presence of different object types and land cover classes, such as forests, open areas, lakes, roads and buildings. To enhance the map’s topographic details, a height model is employed, and certain features are added to mimic a conventional topographic map. A brief theoretical section elucidates the fundamentals of deep learning. Additionally, specific technical terms are defined and their application within the context of model usage and successful architectural designs is discussed. The performance metrics of the neural models are explained and subsequently applied in validating the results. The resulting map is validated versus an existing map provided by Lantmäteriet. The results are analyzed, and some shortcomings and advantages are highlighted and discussed. The final result shows that it is possible to make a detailed map based on automatic processes by combining the results of pretrained neural models. The map have some deviations relative the existing maps, the overall accuracy was 0.94, but the deviations seems smaller if you visually compared it with the ortofoto. The maps quality is at least of such good quality that it could serve a visual guide when making yourself a picture of chosen terrain in Sweden