@article{KamjunkeBeckersHerzsprungetal.2022, author = {Kamjunke, Norbert and Beckers, Liza-Marie and Herzsprung, Peter and von T{\"u}mpling, Wolf and Lechtenfeld, Oliver and Tittel, J{\"o}rg and Risse-Buhl, Ute and Rode, Michael and Wachholz, Alexander and Kallies, Rene and Schulze, Tobias and Krauss, Martin and Brack, Werner and Comero, Sara and Gawlik, Bernd Manfred and Skejo, Hello and Tavazzi, Simona and Mariani, Giulio and Borchardt, Dietrich and Weitere, Markus}, title = {Lagrangian profiles of riverine autotrophy, organic matter transformation, and micropollutants at extreme drought}, series = {The science of the total environment : an international journal for scientific research into the environment and its relationship with man}, volume = {828}, journal = {The science of the total environment : an international journal for scientific research into the environment and its relationship with man}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0048-9697}, doi = {10.1016/j.scitotenv.2022.154243}, pages = {14}, year = {2022}, abstract = {On their way from inland to the ocean, flowing water bodies, their constituents and their biotic communities are ex-posed to complex transport and transformation processes. However, detailed process knowledge as revealed by La-grangian measurements adjusted to travel time is rare in large rivers, in particular at hydrological extremes. To fill this gap, we investigated autotrophic processes, heterotrophic carbon utilization, and micropollutant concentrations applying a Lagrangian sampling design in a 600 km section of the River Elbe (Germany) at historically low discharge. Under base flow conditions, we expect the maximum intensity of instream processes and of point source impacts. Phy-toplankton biomass and photosynthesis increased from upstream to downstream sites but maximum chlorophyll con-centration was lower than at mean discharge. Concentrations of dissolved macronutrients decreased to almost complete phosphate depletion and low nitrate values. The longitudinal increase of bacterial abundance and production was less pronounced than in wetter years and bacterial community composition changed downstream. Molecular analyses revealed a longitudinal increase of many DOM components due to microbial production, whereas saturated lipid-like DOM, unsaturated aromatics and polyphenols, and some CHOS surfactants declined. In decomposition exper-iments, DOM components with high O/C ratios and high masses decreased whereas those with low O/C ratios, low masses, and high nitrogen content increased at all sites. Radiocarbon age analyses showed that DOC was relatively old (890-1870 years B.P.), whereas the mineralized fraction was much younger suggesting predominant oxidation of algal lysis products and exudates particularly at downstream sites. Micropollutants determining toxicity for algae (terbuthylazine, terbutryn, isoproturon and lenacil), hexachlorocyclohexanes and DDTs showed higher concentrations from the middle towards the downstream part but calculated toxicity was not negatively correlated to phytoplankton. Overall, autotrophic and heterotrophic process rates and micropollutant concentrations increased from up-to down-stream reaches, but their magnitudes were not distinctly different to conditions at medium discharges.}, language = {en} } @article{PerillonvandeWeyerPaezoltetal.2018, author = {Perillon, Cecile and van de Weyer, Klaus and P{\"a}zolt, Jens and Kasprzak, Peter and Hilt, Sabine}, title = {Changes in submerged macrophyte colonization in shallow areas of an oligo-mesotrophic lake and the potential role of groundwater}, series = {Limnologica : ecology and management of inland waters}, volume = {68}, journal = {Limnologica : ecology and management of inland waters}, publisher = {Elsevier}, address = {Jena}, issn = {0075-9511}, doi = {10.1016/j.limno.2017.03.002}, pages = {168 -- 176}, year = {2018}, abstract = {Groundwater influx can significantly contribute to nutrient budgets of lakes and its influence is strongest in shallow littoral areas. In oligo-or mesotrophic systems, additional nutrient supply by groundwater influx may affect benthic primary producers and their interactions. Potential changes can be expected in community composition, biomass, stoichiometry and interactions between submerged macrophytes and epiphyton.}, language = {en} } @phdthesis{Buechele2020, author = {B{\"u}chele, Dominique}, title = {Entwicklung einer robusten Online-Methode zur Bestimmung von N{\"a}hrelementen in Ackerb{\"o}den mit einem Energie-dispersiven RFA-Sensor}, doi = {10.25932/publishup-48373}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-483735}, school = {Universit{\"a}t Potsdam}, pages = {IX, 106, XLV}, year = {2020}, abstract = {Im Rahmen der vom Bundesministerium f{\"u}r Bildung und -forschung gef{\"o}rderten Forschungsinitiative „BonaRes - Boden als nachhaltige Ressource der Bio{\"o}konomie" soll sich das Teilprojekt „I4S - integrated system for site-specific soil fertility management" der Entwicklung eines integrierten Systems zum ortsspezifischen Management der Bodenfruchtbarkeit widmen. Hierf{\"u}r ist eine Messplattform zur Bestimmung relevanter Bodeneigenschaften und der quantitativen Analyse ausgew{\"a}hlter Makro- und Mikron{\"a}hrstoffe geplant. In der ersten Phase dieses Projekts liegt das Hauptaugenmerk auf der Kalibrierung und Validierung der verschiedenen Sensoren auf die Matrix Boden, der Probennahme auf dem Acker und der Planung sowie dem Aufbau der Messplattform. Auf dieser Plattform sollen in der zweiten Phase des Projektes die verschiedenen Bodensensoren installiert, sowie Modelle und Entscheidungsalgorithmen zur Steuerung der D{\"u}ngung und dementsprechend Verbesserung der Bodenfunktionen erstellt werden. Ziel der vorliegenden Arbeit ist die Grundlagenuntersuchung und Entwicklung einer robusten Online-Analyse mittels Energie-dispersiver R{\"o}ntgenfluoreszenzspektroskopie (EDRFA) zur Quantifizierung ausgew{\"a}hlter Makro- und Mikron{\"a}hrstoffe in B{\"o}den f{\"u}r eine kosteng{\"u}nstige und fl{\"a}chendeckende Kartierung von Ackerfl{\"a}chen. F{\"u}r die Entwicklung eines Online-Verfahrens wurde ein dem Stand der Technik entsprechender R{\"o}ntgenfluoreszenzmesskopf in Betrieb genommen und die dazugeh{\"o}rigen Ger{\"a}teparameter auf die Matrix Boden optimiert. Die Bestimmung der analytischen Qualit{\"a}ts-merkmale wie Pr{\"a}zision und Nachweisgrenzen fand f{\"u}r eine Auswahl an N{\"a}hrelementen von Aluminium bis Zink statt. Um eine m{\"o}glichst Matrix-angepasste Kalibrierung zu erhalten, wurde sowohl mit zertifizierten Referenzmaterialien (CRM), als auch mit Ackerb{\"o}den kalibriert. Da einer der gr{\"o}ßten Nachteile der R{\"o}ntgenfluoreszenzanalyse die Beeinflussung durch Matrixeffekte ist, wurde neben der klassischen univariaten Datenauswertung auch die chemometrische multivariate Methode der Partial Least Squares Regression (PLSR) eingesetzt. Die PLSR bietet dabei den Vorteil, Matrixeffekte auszugleichen, wodurch robustere Kalibriermodelle erhalten werden k{\"o}nnen. Zus{\"a}tzlich wurde eine Hauptkomponentenanalyse (PCA) durchgef{\"u}hrt, um Gemeinsamkeiten und Ausreißer innerhalb des Probensets zu identifizieren. Es zeigte sich, dass eine Klassifizierung der B{\"o}den anhand ihrer Textur Sand, Schluff, Lehm und Ton m{\"o}glich ist. Aufbauend auf den Ergebnissen idealer Bodenproben (zu Tabletten gepresste luftgetrocknete Proben mit Korngr{\"o}ßen < 0,5 mm) wurde im Verlauf dieser Arbeit die Probenvorbereitung immer weiter reduziert und der Einfluss verschiedener Kenngr{\"o}ßen untersucht. Diese Einflussfaktoren k{\"o}nnen die Dichte und die Homogenit{\"a}t der Probe, sowie Korngr{\"o}ßeneffekte und die Feuchtigkeit sein. Anhand des RMSE (Wurzel der mittleren Fehlerquadratsumme) und unter Ber{\"u}cksichtigung der Residuen werden die jeweils erstellten Kalibriermodelle miteinander verglichen. Um die G{\"u}te der Modelle zu bewerten, wurden diese mit einem Testset validiert. Hierf{\"u}r standen 662 Bodenproben von 15 verschiedenen Standorten in Deutschland zur Verf{\"u}gung. Da die Ergebnisse an gepressten Tabletten f{\"u}r die Elemente Al, Si, K, Ca, Ti, Mn, Fe und Zn den Anforderungen f{\"u}r eine sp{\"a}tere Online-Analyse entsprechen, wurden im weiteren Verlauf dieser Arbeit Kalibriermodelle mit losen Bodenproben erstellt. Auch hier konnten gute Ergebnisse durch ausreichende Nachweisgrenzen und eine niedrige gemittelte Messabweichung bei der Vorhersage unbekannter Testproben erzielt werden. Es zeigte sich, dass die Vorhersagef{\"a}higkeit mit der multivariaten PLSR besser ist als mit der univariaten Datenauswertung, insbesondere f{\"u}r die Elemente Mn und Zn. Der untersuchte Einfluss der Feuchtigkeit und der Korngr{\"o}ßen auf die Quantifizierung der Elementgehalte war vor allem bei leichteren Elementen deutlich zu sehen. Es konnte schließlich eine multivariate Kalibrierung unter Ber{\"u}cksichtigung dieser Faktoren f{\"u}r die Elemente Al bis Zn erstellt werden, so dass ein Einsatz an B{\"o}den auf dem Acker m{\"o}glich sein sollte. Eine h{\"o}here Messunsicherheit muss dabei einkalkuliert werden. F{\"u}r eine sp{\"a}tere Probennahme auf dem Feld wurde zudem der Unterschied zwischen statischen und dynamischen Messungen betrachtet, wobei sich zeigte, dass beide Varianten genutzt werden k{\"o}nnen. Zum Abschluss wurde der hier eingesetzte Sensor mit einem kommerziell erh{\"a}ltlichen Hand-Ger{\"a}t auf sein Quantifizierungspotential hin verglichen. Der Sensor weist anhand seiner Ergebnisse ein großes Potential als Online-Sensor f{\"u}r die Messplattform auf. Die Ergebnisse unter Laborbedingungen zeigen, dass eine robuste Analyse Ackerb{\"o}den unter Ber{\"u}cksichtigung der Einflussfaktoren m{\"o}glich ist.}, language = {de} } @article{PerillonHilt2016, author = {P{\´e}rillon, C{\´e}cile and Hilt, Sabine}, title = {Groundwater influence differentially affects periphyton and macrophyte production in lakes}, series = {Hydrobiologia : acta hydrobiologica, hydrographica, limnologica et protistologica}, volume = {778}, journal = {Hydrobiologia : acta hydrobiologica, hydrographica, limnologica et protistologica}, publisher = {Springer}, address = {Dordrecht}, issn = {0018-8158}, doi = {10.1007/s10750-015-2485-9}, pages = {91 -- 103}, year = {2016}, abstract = {Groundwater influx can significantly contribute to nutrient and carbon budgets of lakes, and its influence is the strongest in littoral areas dominated by macrophytes and periphyton. We have reviewed the effects of groundwater-borne nitrogen and phosphorus and dissolved inorganic and organic carbon (DIC, DOC) on these benthic primary producers in lakes. We develop a hypothesis for groundwater effects including the less studied impacts of periphyton shading on macrophytes. Groundwater-borne nutrients and DIC promote both macrophytes and periphyton. Direct studies on groundwater-borne DOC effects are lacking, but coloured DOC contributes to light attenuation and thus can restrict the growth of benthic primary producers. We predict that above certain threshold levels of nutrient influx by groundwater, periphyton and macrophyte biomass should decline owing to shading by phytoplankton and periphyton, respectively. However, because of their higher light requirements, those thresholds should be lower for macrophytes. For macrophytes, a threshold level is also predicted for a shift from DIC limitation to light limitation. Differences in light requirements are expected to result in lower thresholds of DOC loading for declines of macrophytes than periphyton.}, language = {en} } @article{McCrickerdLensingYeomans2015, author = {McCrickerd, Keri and Lensing, Johanna Nele and Yeomans, Martin R.}, title = {The impact of food and beverage characteristics on expectations of satiation, satiety and thirst}, series = {Food quality and preference}, volume = {44}, journal = {Food quality and preference}, publisher = {Elsevier}, address = {Oxford}, issn = {0950-3293}, doi = {10.1016/j.foodqual.2015.04.003}, pages = {130 -- 138}, year = {2015}, abstract = {The expected impact of a food or drink on appetite can influence decisions around eating and the actual experience of satiation and satiety post-consumption. This study explored the relationship between a product's anticipated sensory characteristics and its expected impact on feelings of hunger, fullness and thirst. Female participants (n = 118) evaluated 40 widely available food and beverage products (varying in physical characteristics, packaging, serving size and total energy content) for anticipated sensory characteristics, pleasantness and familiarity, alongside expected impact on immediate fullness, hunger after one hour and thirst both immediately and after one hour. Correlations revealed that the most caloric products and those anticipated to be creamier were expected to be more filling and hunger suppressing than the products with lower energy content and expected to be less creamy. Total energy was the best predictor of expected satiation and satiety. We observed that beverage products were expected to be similarly satiating as food products (including liquid, solid and semi-solids) with a similar total energy content and expected creaminess. On the other hand, products expected to be less salty and thick were expected to be most thirst-quenching, and these tended to be beverage products, regardless of their total energy content. These results are in line with emerging evidence suggesting that certain sensory cues associated with nutrients can be used to estimate the satiating power of other foods, including beverages. Beverages are expected to be uniquely thirst-quenching, but are not always expected to have a low satiety-value. (C) 2015 Elsevier Ltd. All rights reserved.}, language = {en} } @article{ZamagniMuttiKosir2012, author = {Zamagni, Jessica and Mutti, Maria and Kosir, Adrijan}, title = {The evolution of mid paleocene-early eocene coral communities how to survive during rapid global warming}, series = {Palaeogeography, palaeoclimatology, palaeoecology : an international journal for the geo-sciences}, volume = {317}, journal = {Palaeogeography, palaeoclimatology, palaeoecology : an international journal for the geo-sciences}, number = {2}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0031-0182}, doi = {10.1016/j.palaeo.2011.12.010}, pages = {48 -- 65}, year = {2012}, abstract = {Today, diverse communities of zooxanthellate corals thrive, but do not build reef, under a wide range of environmental conditions. In these settings they inhabit natural bottom communities, sometimes forming patch-reefs, coral carpets and knobs. Episodes in the fossil record, characterized by limited coral-reef development but widespread occurrence of coral-bearing carbonates, may represent the fossil analogs of these non-reef building, zooxanthellate coral communities. If so, the study of these corals could have valuable implications for paleoenvironmental reconstructions. Here we focus on the evolution of early Paleogene corals as a fossil example of coral communities mainly composed by zooxanthellate corals (or likely zooxanthellate), commonly occurring within carbonate biofacies and with relatively high diversity but with a limited bioconstructional potential as testified by the reduced record of coral reefs. We correlate changes of bioconstructional potential and community compositions of these fossil corals with the main ecological/environmental conditions at that time. The early Paleogene greenhouse climate was characterized by relatively short pulses of warming with the most prominent occurring at the Paleocene-Eocene boundary (PETM event), associated with high weathering rates, nutrient fluxes, and pCO(2) levels. A synthesis of coral occurrences integrated with our data from the Adriatic Carbonate Platform (SW Slovenia) and the Minervois region (SW France), provides evidence for temporal changes in the reef-building capacity of corals associated with a shift in community composition toward forms adapted to tolerate deteriorating sea-water conditions. During the middle Paleocene coral-algal patch reefs and barrier reefs occurred from shallow-water settings, locally with reef-crest structures. A first shift can be traced from middle Paleocene to late Paleocene, with small coral-algal patch reefs and coral-bearing mounds development in shallow to intermediate water depths. In these mounds corals were highly subordinated as bioconstructors to other groups tolerant to higher levels of trophic resources (calcareous red algae, encrusting foraminifera, microbes, and sponges). A second shift occurred at the onset of the early Eocene with a further reduction of coral framework-building capacity. These coral communities mainly formed knobs in shallow-water, turbid settings associated with abundant foraminiferal deposits. We suggest that environmental conditions other than high temperature determined a combination of interrelated stressors that limited the coral-reef construction. A continuous enhancement of sediment load/nutrients combined with geochemical changes of ocean waters likely displaced corals as the main bioconstructors during the late Paleocene-early Eocene times. Nonetheless, these conditions did not affect the capacity of some corals to colonize the substrate, maintain biodiversity, and act as locally important carbonate-sediment producers, suggesting broad environmental tolerance limits of various species of corals. The implications of this study include clues as to how both ancient and modern zooxanthellate corals could respond to changing climate.}, language = {en} } @article{HesseKrysanovaVetteretal.2013, author = {Hesse, Cornelia and Krysanova, Valentina and Vetter, Tobias and Reinhardt, Julia}, title = {Comparison of several approaches representing terrestrial and in-stream nutrient retention and decomposition in watershed modelling}, series = {Ecological modelling : international journal on ecological modelling and engineering and systems ecolog}, volume = {269}, journal = {Ecological modelling : international journal on ecological modelling and engineering and systems ecolog}, number = {34}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0304-3800}, doi = {10.1016/j.ecolmodel.2013.08.017}, pages = {70 -- 85}, year = {2013}, abstract = {Retention and transformation of nutrients within a river catchment are important mechanisms influencing water quality measured at the watershed outlet. Nutrient storage and reduction can occur in soils as well as in the river and should be considered in water quality modelling. Consideration is possible using various methods at several points during modelling cascade. The study compares the effects of five different equation sets implemented into the Soil and Water Integrated Model (SWIM), one describing terrestrial and four in-stream retention with a rising complexity (including algal growth and death at the highest complexity level). The influences of the different methods alone and in combinations on water quality model outputs (NO3-N, NH4-N, PO4-P) were analyzed for the outlet of the large-scale Saale basin in Germany. Experiments revealed that nutrient forms coming primarily from diffuse sources are mostly influenced by retention processes in the soils of the catchment, and river processes are less important. Nutrients introduced to the river mainly by point sources are more subject to retention by in-stream processes, but both nutrient retention and transformation processes in soils and rivers have to be included. Although the best overall results could be achieved at the highest complexity level, the calibration efforts for this case are extremely high, and only minor improvements of overall model performance with the highest complexity were detected. Therefore, it could be reasoned that for some research questions also less complex model approaches would be sufficient, which could help to reduce unnecessary complexity and diminish high uncertainty in water quality modelling at the catchment scale. (C) 2013 Elsevier B.V. All rights reserved.}, language = {en} }