Ventilation of the Mediterranean Sea constrained by multiple transient tracer measurements

Ventilation is the primary pathway for atmosphere–ocean boundary perturbations, such as temperature anomalies, to be relayed to the ocean interior. It is also a conduit for gas exchange between the interface of atmosphere and ocean. Thus it is a mechanism whereby, for instance, the ocean interior is oxygenated and enriched in anthropogenic carbon. The ventilation of the Mediterranean Sea is fast in comparison to the world ocean and has large temporal variability. Here we present transient tracer data from a field campaign in April 2011 that sampled a unique suite of transient tracers (SF6, CFC-12, 3H and 3He) in all major basins of the Mediterranean. We apply the transit time distribution (TTD) model to the data in order to constrain the mean age, the ratio of the advective / diffusive transport and the number of water masses significant for ventilation. We found that the eastern part of the eastern Mediterranean can be reasonably described with a one-dimensional inverse Gaussian TTD (IG-TTD), and thus constrained with two independent tracers. The ventilation of the Ionian Sea and the western Mediterranean can only be constrained by a linear combination of IG-TTDs. We approximate the ventilation with a one-dimensional, two inverse Gaussian TTD (2IG-TTD) for these areas and demonstrate a possibility of constraining a 2IG-TTD from the available transient tracer data. The deep water in the Ionian Sea has a mean age between 120 and 160 years and is therefore substantially older than the mean age of the Levantine Basin deep water (60–80 years). These results are in contrast to those expected by the higher transient tracer concentrations in the Ionian Sea deep water. This is partly due to deep water of Adriatic origin having more diffusive properties in transport and formation (i.e., a high ratio of diffusion over advection), compared to the deep water of Aegean Sea origin that still dominates the deep Levantine Basin deep water after the Eastern Mediterranean Transient (EMT) in the early 1990s. The tracer minimum zone (TMZ) in the intermediate of the Levantine Basin is the oldest water mass with a mean age up to 290 years. We also show that the deep western Mediterranean has contributed approximately 40% of recently ventilated deep water from the Western Mediterranean Transition (WMT) event of the mid-2000s. The deep water has higher transient tracer concentrations than the mid-depth water, but the mean age is similar with values between 180 and 220 years

Guano: The White Gold of the Seabirds

The term “Guano” applies to natural mineral deposits consisting of excrements, eggshells and carcasses of dead seabirds found in almost rainless, hot-dry climatic regions and corresponding fertilizers. Guanos are classified according to age, genesis, geographical origin and chemical composition. Main types are nitrogen- and phosphate Guanos. Phosphate Guanos require a calcareous subsoil for the development, while nitrogen Guanos are formed only under the special climatic conditions of the subtropical-edge tropical high pressure belt with coastal deserts. The most significant nitrogen Guano is the Peru-Guano, which has been used over 2000 years as agricultural fertilizer in Peru. In Europe the application of Guano as fertilizer emerged in the 1840 as “Guano boom” and lasted until the early twentieth century when Guano was replaced by industrial manufactured fertilizers. Only a small quantity is still exported to Europe as additive to organic/mineral fertilizers, more for image boosting than for effect

Climate change and the rise of infectious diseases : an Arctic perspective

Animals that carry infectious microorganisms are migrating towards the North with climatechange transitions of Arctic landscapes into warmer biomes. This threatens to change societal exposure to infectious diseases and affect the OneHealth status of Arctic cultures. OneHealth takes a multidisciplinary approach to health risks and risk mitigation for humans, animals, plants and the environment with the understanding that human health and welfare is dependent on ecosystem health. At the CLINF Nordic Center of Excellence, Birgitta Evengård, Tomas Thierfelder, Svenja Stöven, and scientists from eight nations recently collaborated to predict the effects of climate change on the epidemiology of climate-sensitive infections. With a focus on international collaboration and harnessing traditional knowledge, CLINF (Climate-change effects on the epidemiology of infectious diseases and the impacts on Northern societies) supports evidence-based policy aimed at preventing or mitigating this most serious of global challenges

Ozeanventilation und anthropogener Kohlenstoff basierend auf evaluierten Spurengasanwendungen

This thesis includes three manuscripts. The first describes the ventilation of the Mediterranean Sea in 2011 based on multiple transient tracer measurements. The second evaluates the application of different transient tracers and the IG-TTD model by using several data sets from the South Atlantic and Southern Ocean. The third manuscript intorduces a new theory about saturation states of transient tracers and provides a flux estimate of anthropogenic carbon through Fram Strait in 2012.Diese Dissertation besteht aus drei Manuskripten. Das erste Manuskript beschreibt die Ventilation des Mittelmeeres in 2011 basierend auf mehreren Spurengasmessungen. Das zweite Manuskript evaluiert die Anwendung von Spurengasen und dem IG-TTD Modell anahand diverser Datensätze aus dem Südatlantik und dem Südlichem Ozean, Das dritte Manuskript führt eine neue Theorie über Sättigungszustände der Spurengase ein und beeinhaltet eine Flussabschätzung von anthropogenem Kohlenstoff durch die Fram Straße in 2012

Perspectives of transient tracer applications and limiting cases

Currently available transient tracers have different application ranges that are defined by their temporal input (chronological transient tracers) or their decay rate (radioactive transient tracers). Transient tracers range from tracers for highly ventilated water masses such as sulfur hexafluoride (SF6) through tritium (3H) and chlorofluorocarbons (CFCs) up to tracers for less ventilated deep ocean basins such as argon-39 (39Ar) and radiocarbon (14C). In this context, highly ventilated water masses are defined as water masses that have been in contact with the atmosphere during the last decade. Transient tracers can be used to empirically constrain the transit time distribution (TTD), which can often be approximated with an inverse Gaussian (IG) distribution. The IG-TTD provides information about ventilation and the advective/diffusive characteristics of a water parcel. Here we provide an overview of commonly used transient tracer couples and the corresponding application range of the IG-TTD by using the new concept of validity areas. CFC-12, CFC-11 and SF6 data from three different cruises in the South Atlantic Ocean and Southern Ocean as well as 39Ar data from the 1980s and early 1990s in the eastern Atlantic Ocean and the Weddell Sea are used to demonstrate this method. We found that the IG-TTD can be constrained along the Greenwich Meridian south to 46° S, which corresponds to the Subantarctic Front (SAF) denoting the application limit. The Antarctic Intermediate Water (AAIW) describes the limiting water layer in the vertical. Conspicuous high or lower ratios between the advective and diffusive components describe the transition between the validity area and the application limit of the IG-TTD model rather than describing the physical properties of the water parcel. The combination of 39Ar and CFC data places constraints on the IG-TTD in the deep water north of the SAF, but not beyond this limit

Demand for renewable resources

In the first paper, we show that a lower importance of catch in recreational fishing may result in higher catches. While this effect also holds under first-best management, it may destabilize open-access recreational fisheries to the point of stock collapse. The second paper analyzes the political economy of resource management. We show that resource users (the processing industry, consumers) and factor owners (capital and labor employed in resource harvesting) may favor inefficiently high harvest rates up to open-access levels. This may explain why public resource management is often very inefficient. The third paper models trade in renewable resources as stipulated not only by autarky price differences, but also by consumers' love of variety. We show that the love-of-variety effect enables welfare gains from trade even if total consumption decreases. Total consumption may decrease because the love of variety weakens the link between resource scarcity and demand

Guano – a historical fertilizer

Als Guanos werden Lagerstätten bezeichnet, die in nahezu regenlosen und warmen Klimaten aus den Exkrementen, Eierschalen und Kadavern von Seevögeln entstehen und den gleichnamigen Dünger erzeugen. Dieser organische Dünger lässt sich unterscheiden nach seinem Alter und seiner Genese, seiner geographischen Herkunft, seinen verschiedenen tierischen Produzenten und nach seiner chemischen Zusammensetzung. Die beiden Haupt­typen sind Stickstoff- und Phosphat-Guanos. Phosphat-Guanos benötigen für ihre Entstehung einen kalkhaltigen Untergrund, Stickstoff-Guano-Lagerstätten entstehen unter klimatischen Sonderbedingungen im Bereich des subtropisch-randtropischen Hochdruckgürtels mit seinen Küstenwüsten, deren Bildung durch kalte und sehr nährstoffreiche Auftriebsgewässer geprägt ist. Der bedeutendste Guano ist der Peru-Guano, der bereits über 2000 Jahre als natürlicher Dünger in Peru verwendet wird. In Europa brach ab 1840 der Guano-Boom aus und dauerte bis Anfang des 20. Jahrhunderts als Guano durch industrielle Dünger ersetzt wurde. Nachdem die Guano-Lager­stätten nahezu erschöpft waren, führte die peruanische Regierung eine strenge Reglementierung für den Abbau und Auflagen zur nachhaltigen Bewirtschaftung der Lager­stätten ein. Die Abbautechnik erfolgt in nahezu unveränderter Form. Der gegenwärtig erzeugte Guano wird zu Vorzugspreisen an die peruanische Landbevölkerung abgegeben. Nur noch ein kleiner Anteil wird auf den euro­päischen Markt zur Veredlung von Gartendüngern exportiert. Ein Nischenprodukt stellt Fledermaus-Guano dar, der eine Sonderstellung einnimmt. DOI: 10.5073/JfK.2016.07.02, https://doi.org/10.5073/JfK.2016.07.02As guanos are called natural mineral deposits of almost rainless hot-dry climatic regions composed by excrements, eggshells and carcasses of dead seabirds which are components of the correspondent manure used as fertilizer. The organic fertilizer is differed relating to its age, genesis, geographical origin, several animal producers and chemical composition. The main types are Nitrogen and Phosphate guanos. Phosphate guano requires a calcareous subsoil for the development, while Nitrogen guano deposits are formed under special climatic conditions as the area of the subtropical-edge tropical high pressure belt with coastal deserts. Its formation is marked by cold and highly nutritious waters. The most significant nitrogen guano is the Peru-guano, which has been used over 2000 years as agricultural fertilizer in Peru. In Europe emerged the application of guano as fertilizer in 1840 as “guano boom” and lasted until the early 20th century when Guano was replaced by industrial manufactured fertilizers. Upon Guano residues are exploited almost completely the Peruvian government started the sustainable guano retrieval Guano currently produced is discharged at preferential prices to the Peruvian rural population. Only a small quantity is still exported to Europe as fertilizer enhancement. A niche product is bat guano, which occupies a special position. DOI: 10.5073/JfK.2016.07.02, https://doi.org/10.5073/JfK.2016.07.0