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Daphnia hybrids

Das Projekt "Daphnia hybrids" wird vom Umweltbundesamt gefördert und von Universität Konstanz, Limnologisches Institut durchgeführt. Hybrids of the water flea Daphnia occur in many lakes. However, little is known about the factors that cause the success of Daphnia hybrids. In a joint project of two laboratories we study the possible role of biotic interactions in the maintenance of a Daphnia hybrid complex. Daphnia hyalina, D. galeata and their hybrids occur in Bodensee and in Greifensee. The parent species are more abundant in Lake Constance, while hybrids dominate in Greifensee. Both lakes differ in important aspects (morphometry, trophic state), which is reflected by different biotic influences con Daphnia. Compared to Lake Constance, Daphnia in Greifensee are more often exposed to low quality food (toxic blue-greens) and have less of a refuge from fish predation (due the anoxic hypolimnion). Differences between both lakes in the invertebrate predation regime and in the parasite load of Daphnia are very probable. Besides field sampling programmes, we want to establish a collection of about 50 Daphnia clones from both lakes (parent species and hybrids, recent clones and old clones hatched from sediment cores). These clones will be used for life history experiments in the laboratory to test the influences of low quality food, of fish kairomones, of invertebrate predator kairomones and of a protozoan parasite. Food quality and invertebrate predator experiments will be done in Konstanz; parasite and fish experiments will be done in Dübendorf.

Sub project: Match and mismatch between phyto- and zooplankton during spring succession: an experimental analysis with Baltic Sea plankton

Das Projekt "Sub project: Match and mismatch between phyto- and zooplankton during spring succession: an experimental analysis with Baltic Sea plankton" wird vom Umweltbundesamt gefördert und von Helmholtz-Zentrum für Ozeanforschung Kiel (GEOMAR) durchgeführt. It shall be investigated, how the spring succession of phyto- and zooplankton will change in response to the predicted climate change, in particular to winter warming. Plankton from the Kiel Bight, Baltic Sea, will serve as a model system for moderately deep water bodies, where the phytopankton spring bloom can start before the onset of thermal stratification. While the start of the phytoplankton spring bloom is predicted to be independent of temperature, growth processes of heterotrophs obviously are. This should lead to changed synchronies in the growth and activity patterns of the different components of the plankton community and to a potential mismatch in the demand- supply relationship between consumers and their food organisms. With the help of indoor mesocosm experiments (8 units) and a simultaneous field monitoring program (started already in 2002) the response of phytoplankton and zooplankton growth and activity patterns, shifts in species composition, patterns of resource limitation, matter and energy transfer between trophic levels, and zooplankton fecundity shall be studied.

Properties of solitary wave trains at internal fronts in Lake Constance

Das Projekt "Properties of solitary wave trains at internal fronts in Lake Constance" wird vom Umweltbundesamt gefördert und von Universität Konstanz, Limnologisches Institut durchgeführt. In the thermocline of lakes and oceans high-frequency internal waves are considered to be the major source of turbulent kinetic energy and a key process driving vertical mixing. In Lake Constance the most energetic high-frequency waves are typically solitary waves generated at the steepened front of the basin scale internal Kelvin wave. The main questions addressed in this project are how stratification, the characteristics of the internal front and lake-morphometry affect the occurrence and properties of solitary wave trains at the internal front in Lake Constance, how much energy is lost from these solitary waves and the wave front to turbulence in the open water and how the properties of solitary wave trains change along their path of propagation. The study will combine the analysis of existing data on high-frequency temperature time series from several years with a new field experiment. The empirical investigations will be complemented by numerical modeling solving the Korteweg-de Vries / Korteweg-de Vries-Burgers equation with spatially varying coefficients to simulate solitary wave trains at the internal front. The spatial differences in solitary wave amplitude, the frequency of the occurrence of solitary waves provided by the statistical analysis and the empirical estimates of energy dissipation during the passage of solitary waves will provide a basis to assess the role of solitary waves for the energy flux from basin scale motion to turbulence and for mixing in the open water.

Sub project: Influence of temperature and stratification on spring succession of the plankton community in deep lakes

Das Projekt "Sub project: Influence of temperature and stratification on spring succession of the plankton community in deep lakes" wird vom Umweltbundesamt gefördert und von Universität München, Biozentrum Martinsried, Department Biologie II, Abteilung Evolutionsökologie durchgeführt. A major impact of global warming on European lakes will be mediated through effects on seasonal succession of the plankton. E.g., the timing of the spring clearwater phase (a period of low algal densities caused by intense grazing from Daphnia) is linked to climate, with warmer winters being followed by an earlier onset and a longer duration of the clearwater phase, and an earlier onset of the spring increase and the summer decline of Daphnia. There are two non-exclusive hypotheses by which mild winters might favour an early build-up of Daphnia biomass: (i) enhanced algal production; (ii) increased metabolic rate. Both depend on the seasonal progression of thermal stratification of lakes. We propose two field experiments designed to disentangle the separate impacts of stratification depth, temperature, and nutrient availability on seasonal succession in the plankton. We will also search existing lake data for trends in the seasonal development of these physico-chemical variables that are driven by interannual climate variability. The experiments will run from April to June and cross-classify (i) three mixing depths with two temperatures (ambient/reduced) in presence and absence of a hypolimnion, and (ii) two temporal patterns of seasonal stratification (early/late) with two temperatures (ambient/ reduced) and two nutrient levels (ambient/enhanced). The data search will focus on regularly stratifying, deep lakes for which data are available with high resolution and for greater than 5 years. Our ultimate goal is to link climate variables to key processes in the plankton in order to predict realistic scenarios of climatic forcing of spring and summer succession in the plankton.

In situ monitoring of oxygen depletion in hypoxic ecosystems of coastal and open seas, and land-locked water bodies (HYPOX)

Das Projekt "In situ monitoring of oxygen depletion in hypoxic ecosystems of coastal and open seas, and land-locked water bodies (HYPOX)" wird vom Umweltbundesamt gefördert und von Max-Planck-Institut für marine Mikrobiologie durchgeführt. Objective: Hypoxic (low oxygen) conditions in aquatic ecosystems increase in number, duration and extent due to global warming and eutrophication. Global warming will lead to degassing of oxygen, increased stratification, reduced deep-water circulation and changes in wind patterns affecting transport and mixing. Projected increases in hypoxia (e.g. doubling of dead zones) are accompanied by enhanced emission of greenhouse gases, losses in biodiversity, ecosystem functions and services such as fisheries, aquaculture and tourism. A better understanding of global changes in oxygen depletion requires a global observation system continuously monitoring oxygen at high resolution, including assessment of the role of the seafloor in controlling the sensitivity of aquatic systems to and recovery from hypoxia. Here we propose to monitor oxygen depletion and associated processes in aquatic systems that differ in oxygen status or sensitivity towards change: open ocean, oxic with high sensitivity to global warming (Arctic), semi-enclosed with permanent anoxia (Black Sea, Baltic Sea) and seasonally or locally anoxic land-locked systems (fjords, lagoons, lakes) subject to eutrophication. We will improve the capacity to monitor oxygen depletion globally, by implementing reliable long-term sensors to different platforms for in situ monitoring; and locally by training and implementing competence around the Black Sea. Our work will contribute to GEOSS tasks in the water, climate, ecosystem and biodiversity work plans, and comply to GEOSS standards by sharing of observations and products with common standards and adaptation to user needs using a state of the art world data centre. We will connect this project to the GOOS Regional Alliances and the SCOR working group and disseminate our knowledge to local, regional and global organisations concerned with water and ecosystem health and management.

Entwicklung eines statistischen Designs für die zweite Bodenzustandserhebung Wald (BZE 2)

Das Projekt "Entwicklung eines statistischen Designs für die zweite Bodenzustandserhebung Wald (BZE 2)" wird vom Umweltbundesamt gefördert und von Universität Hamburg, Arbeitsbereich für Weltforstwirtschaft und Institut für Weltforstwirtschaft des Friedrich-Löffler-Institut, Bundesforschungsinstitut für Tiergesundheit durchgeführt. Project objectives: Some fundamental statistical questions are existing in the end of implementation phase for the second soil condition survey (BZE 2) in Germany. These are described in a memorandum from the Referat 533 of BMVEL (533-7673-1/4) from 30.07.2004. This project is to be supposed to develop and implement a mathematical-statistical way for evaluation of the second soil condition survey. In a first Step possibilities and the potential for stratification to reduce the sampling error will be show. Existing Follow-up Inventory Concepts will be discussed under the special context of BZE. Soil parameters vary on a very small spatial scale. To estimate the error arising from the kind of sampling design on a sampling plot samples on a scale from 0 to 20 meters will be collected and completed by data sets suited for such questions. These data are the base for geo-statistical analysis. The error due to the sampling design can be quantified by various simulations. In the preface of BZE a set of soil samples are analysed from different laboratories and by different laboratory methods. The Varity of these results could be seen as a scope of bias. All these errors lead to an overall error budget, which shows the proportion between the individual error sources and the source for future research. Project results: This project is to be supposed to develop and implement a mathematical-statistical way for evaluation of the second soil condition survey under the scope, given by the memorandum from the Referat 533 of BMVEL (533-7673-1/4) from 30.07.2004. With the end of the project an objective scale for evaluating different versions for taking soil samples is available. First times, the relation of used resources and the realized sampling error for soil inventories can be evaluated. So there is the chance for a better estimation of error scope and for the decrease of costs in future inventories. Contribution of University of Hamburg: - developing and suggesting a mathematical statistical way for the evaluation of the second soil condition survey; - analyzing the potential of stratification to reduce the sampling error; - compiling an overall error budget estimated from errors of sampling design, local variability of soil parameters and different means of analyzing soil parameters in the laboratory.

A6: Klimawandel und Sauerstoffminimum-Bedingungen auf 100 - 1000 Jahre Zeitskalen

Das Projekt "A6: Klimawandel und Sauerstoffminimum-Bedingungen auf 100 - 1000 Jahre Zeitskalen" wird vom Umweltbundesamt gefördert und von Christian-Albrechts-Universität zu Kiel, Sektion Geowissenschaften, Institut für Geowissenschaften durchgeführt. Dieses Teilprojekt wird den Zusammenhang zwischen schnell ablaufenden Änderungen in der oberflächennahen Zirkulation bzw. Warmwasser-Deckschicht und Schwankungen in den Sauerstoffminimumzonen (SMZ) im tropischen Ozean für die letzten 20.000 Jahre untersuchen. Dabei sollen Sedimentkerne zur Erstellung von Zeitserien für die ozeanische Klimavariabilität auf Zeitskalen von Jahrhunderten bis Jahrtausenden dienen, die möglicherweise Schwankungen in der Intensität von SMZ gesteuert haben. Der Vergleich solcher natürlichen hydrographischen und biogeochemischen Schwankungen mit den heute ablaufenden Änderungen in den tropischen SMZ soll dann Hinweise geben, ob in jüngsten Aufzeichnungen möglicherweise anthropogene Klimaeffekte erkennbar sind.

FS SONNE - SO 171 - TRACERZIRKEL II: Zirkulation im subtropisch-tropischen Atlantik

Das Projekt "FS SONNE - SO 171 - TRACERZIRKEL II: Zirkulation im subtropisch-tropischen Atlantik" wird vom Umweltbundesamt gefördert und von Universität Bremen, Institut für Umweltphysik, Abteilung Ozeanographie durchgeführt. Ziele: Die Untersuchungen werden im Rahmen des internationalen CLIVAR Projektes durchgeführt. Die speziellen Ziele dieser Forschungsfahrt sind die Untersuchung der Ausbreitung des Labradorseewassers im tropischen und subtropischen Atlantik und der laterale Tiefenwasseraustausch im Atlantik sowie die der Schichtung und Zirkulation des östlichen Randstromes in seinen tieferen Bereichen.

Auswirkungen des Klimawandels auf die Wassergüte von Talsperren

Das Projekt "Auswirkungen des Klimawandels auf die Wassergüte von Talsperren" wird vom Umweltbundesamt gefördert und von Technische Universität Dresden, Institut für Hydrobiologie, Professur für Limnologie (Gewässerökologie) durchgeführt. Anhand der Auswertung von Langzeitdaten deutscher TS unterschiedlicher geografischer Regionen sollen die direkten und indirekten Folgen der Klimaerwärmung unter Betrachtung der jeweiligen Bewirtschaftungsmaßnahmen analysiert werden. Zusätzlich werden mit Freilandprobenahmen an drei sächsischen Talsperren Veränderungen im Metalimnion, welches in besonderer Weise von den Folgen des Klimawandels und veränderter TS-Bewirtschaftung beeinflusst ist, untersucht.

PROCOPE - Kopplung von Zooplanktonpopulationsmodellen mit 3d hydrodynamischen und ökologischen Modellen

Das Projekt "PROCOPE - Kopplung von Zooplanktonpopulationsmodellen mit 3d hydrodynamischen und ökologischen Modellen" wird vom Umweltbundesamt gefördert und von Universität Hamburg, Zentrum für Meeres- und Klimaforschung, Institut für Meereskunde (IfM) durchgeführt. PROCOPE is a DAAD financed German partner program with France, Prof. Dr. Francois Carlotti. The aim is to study the coupling between physical and biological processes in coastal marine ecosystems, using zooplankton models. The representation of zooplankton in ecosystem models is still an open scientific question. Single biomass entity in so called NPZ models, shows a high sensitivity to zooplankton parameters. Zooplankton life durations from few weeks to months, and developmental ontogenetic size changes induce properties of the zooplankton compartment which cannot be represented similarly to phyto- and microzooplankton. - It is time to go beyond the NPZ type models (built for biogeochemical purposes) with new approaches and new techniques. This include new trophic food web models (see GLOBEC modelling report) but also new bio-physical coupled models. We wish to develop numerical models to examina the interactions of physical zooplanktonic population dynamics of several Sea/Baltic Sea Ecosystem and the Biscay Bayecosystem. The main goal is to analyse the zooplankton population dynamics in a three-dimensional frame using circulation, stratification, nutrient and phytoplankton forcing to study regional differences of zooplankton biomasses and weather induced variability. And to answer the following questions: How does the circulation field impact the distribution and population success of major zooplankton species? How do the behavioural and bioenergetic differences of these species interact with the circulation field, prey distribution and temperature to influence their relative population success? How does the interannual variability of the local environment (e.g. from large-scale atmospheric or oceanic fluctuations) modify these distributions and relative success of major zooplankton species?

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