Zimmer, Martin
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Item-typ:Veröffentlichung, Understanding the connectivity between mangrove and terrestrial ecosystems in semi-arid areas of both sides of the Atlantic(2025-08-05); ; 17 30 - Some of the metrics are blocked by yourconsent settings
Item-typ:Veröffentlichung, Exploring carbon dynamics in connected mangrove forests and seagrass beds: How important is it?Carbon sequestration is one of the most important ecosystem services provided by mangrove forests and seagrass beds that helps with climate change adaptation. Mangrove forests and seagrass beds are important ecosystems in tropical and subtropical locations that sequester significant greater amounts of carbon within their living biomass as well as in their sediments compared to terrestrial ecosystems. Ecosystems that exchange energy, organisms and materials are considered connected. This dissertation, however, will focus on connectivity as the specific exchange of particulate organic matter (POM). Connectivity across coastal vegetated ecosystems could have an important impact for ecosystem services across the seascape. Although mangrove forests and seagrass beds usually occur adjacent to each other they are frequently evaluated independently without taking into account how connectivity between these coastal vegetated ecosystems can influence carbon accumulation. Therefore, a comparison of connected with isolated mangrove forests and seagrass beds will help to understand the effect of connectivity on carbon accumulation at the seascape scale. Five field studies in Singapore (Asia), Adelaide (Oceania), Zanzibar (Africa), Florida and Bonaire (Americas), were chosen to evaluate the influence of connectivity. Sampling for sediment carbon content analysis was conducted across all places in different locations with connected mangrove forests and seagrass beds and/or isolated ecosystems. The general hypothesis was that mangrove forests and seagrass beds that are connected with each other would have greater quantities of carbon in the sediment, compared to those that are isolated from each other. Furthermore, other aspects such as connectivity with other ecosystems (i.e. salt marsh, macroalgal beds), community characteristics, sediment nutrient concentration and geomorphic settings were tested and compared separately in each place. Results of this dissertation in Singapore and Zanzibar showed that no significant differences were observed between mangrove forests connected with seagrasses beds and mangrove forests isolated from seagrass beds. Connectivity between mangrove forests and seagrass beds for carbon accumulation only increased sediment carbon accumulation in South Australia´s mangrove forests, where the sediment carbon content was higher in connected forests compared with an isolated mangrove patch. In general, sediment in seagrass beds have higher inorganic carbon indicating that mangrove forests are not the main allochthonous carbon source. Contrary to the general hypothesis, isolated seagrass beds had up to double sediment carbon content compared with connected beds. This was mainly driven by higher amounts of inorganic carbon in isolated beds since sediment organic carbon quantity was similar across the sampled beds. Thus, autochthonous production of inorganic carbon and connectivity with carbonate rich ecosystems (i.e. coral reefs) could be important for seagrass beds carbon accumulation. Although connected seagrass beds did not have higher sediment carbon content compared with isolated beds, results of this dissertation showed that mangrove forests are crucial donors of organic carbon to adjacent ecosystems such as seagrass beds and mud flats. The contributions to POM in the coastal water body of the main primary producers across all coastal vegetated ecosystems were measured in Singapore and South Australia. In both places, mangrove trees contributed between 10 to 70% and significantly more compared with other ecosystems with respect to the area occupied in the seascape by mangrove forests. Additionally, in Singapore and Bonaire it was observed that the export of dissolved organic carbon is an important pathway of exchanging carbon from mangroves forests to adjacent ecosystems. Besides mangrove trees, macroalgae thalli were with 10-50% the main contributors to the POM stocks in Singapore and South Australia. These results highlight the importance of mangrove forests as well as other coastal vegetated ecosystems, such as macroalgal beds, for carbon exchange and potential carbon accumulation across the seascape. Interactions between community composition and environmental parameters (i.e. water particle transportation or sediment nutrient concentration) could enhance the sediment carbon content. In Zanzibar, although functional diversity indices were not associated with higher sediment organic or inorganic carbon content, community species composition associated with prop roots in mangrove forests and large-leaved seagrass plants were correlated with higher sediment carbon content. In both ecosystems the area of tidal channels was also an important predictor of sediment carbon content although there were differences in the influence on sediment organic and inorganic carbon content. Additionally, in Florida the gradient of physical traits of mangrove roots and seagrass plants were compared against different carbon content type (organic and carbonate). A negative correlation was found between the sediment organic carbon content and the root complexity index, whilst higher sediment organic carbon levels were found in areas with higher shoot density and coverage. Besides connectivity other factors at the seascape level such us geomorphic settings or anthropogenic induced changes in the seascape settings could influence the connectivity and the sediment carbon content. In Zanzibar the area of tidal channels as well as the area covered by mangrove forest were positively correlated with sediment organic carbon content in mangrove forests. Anthropogenic induced changes such as changing freshwater fluxes and reduction of mangrove forest area in Singapore as well as reduction of area of healthy mangrove trees in Bonaire could affected carbon accumulation dynamics not only in mangrove forests but also in adjacent coastal ecosystems such as seagrass beds. In both places the same underlying mechanism was discussed, the reduction of mangrove forest area could reduce the exported amount of POM and decrease the amount of carbon accumulated in the adjacent ecosystems. I conclude that connectivity between mangrove forests and seagrass beds is affected by different localized factors and that degrees of connectedness between those two ecosystems and other adjacent ecosystems should be further study. Factors such as mangrove forests cover area, community composition and health state of mangrove communities influence both the sediment carbon accumulation in mangrove forests and their exportation of carbon to adjacent ecosystems. Additionally, including sediment inorganic carbon content in blue carbon studies concerning seagrass beds is critical, since sediment inorganic carbon content was an important component of their sediment carbon content. Geomorphic settings such as presence of low energy streams or rivers as well as presence of macroalgal beds can also enhance sediment carbon accumulation in mangrove forests and seagrass beds. Results of this dissertation in connectivity between different coastal vegetated ecosystems as well as terrestrial ecosystems highlight the importance of the conservation of all interconnected ecosystems (i.e. mangrove forests, seagrass beds, salt marches, macroalgae beds, coral reefs as well as connected terrestrial ecosystems) for carbon accumulation ecosystem service.Dissertation378 436 - Some of the metrics are blocked by yourconsent settings
Item-typ:Veröffentlichung, Justice as a facilitator of mangrove (re)establishment: Perspectives from Colombia and Malaysia(2026-03-27); ; ; Interest in mangrove (re)establishment has grown rapidly in recent decades, driven by climate mitigation goals and ambitious restoration targets. While ecological and technical aspects have received significant attention, the social dimensions of mangrove (re)establishment remain less understood. This thesis examines how issues of justice shape mangrove governance and management, using case studies from Barú, Colombia and Setiu Wetlands, Malaysia. Drawing on an environmental justice framework and qualitative research with local communities, it explores how decision-making processes, the distribution of benefits and burdens, and the recognition of local knowledge and culture influence (re)establishment outcomes. The findings show that although local communities highly value mangrove forests, they are often marginalised in decision-making processes and disproportionately affected by environmental degradation. At the same time, powerful actors frequently play a dual role in both driving mangrove degradation and funding (re)establishment. Overall, the research highlights how power asymmetries undermine both social justice and the outcomes of mangrove (re)establishment efforts.Dissertation18 18 - Some of the metrics are blocked by yourconsent settings
Item-typ:Veröffentlichung, Canopy gap dynamics in mangrove forests: exploring global patterns and drivers(2024-01-19); ; ; Mangrove forests are located at the interface between land and sea in tropical and subtropical lati-tudes. They provide several valuable ecosystem services, including carbon sequestration, habitat for diverse fauna, coastal protection, and serving as a source of fuel and timber for coastal com-munities. However, the unique location of mangrove forests in a highly dynamic environment, makes them susceptible to disturbances which leads to the formation of canopy gaps. Mangrove canopy gaps may counteract senescence, contributing to maintaining the mangrove for-est in a rejuvenated and regenerated state. The rejuvenation and regeneration of canopy gaps have implications for the integrity of the numerous valuable ecosystem services that mangrove forests offer. Despite the socio-ecological implications of canopy gaps, knowledge regarding their global and local extent, drivers, occurrences, densities, and closure rates remains limited. This thesis addresses the knowledge limitation by conducting a comprehensive investigation of the distribution patterns and dynamics of canopy gaps in mangrove forests on both global and local scales. The investigation employs a multifaceted approach, encompassing extensive literature reviews, remote sensing techniques, and predictive models, to explain the patterns of canopy gaps formation, closure dynamics and reveal their underlying drivers while validating their regenera-tion capacity. Canopy gaps are found in 133 mangrove patches distributed across 35 countries spanning Ameri-ca, Africa, Asia, and Oceania. Significant variations in canopy gap sizes, canopy gap densities, and percentage of canopy gaps coverage in mangrove patches across different regions were ob-served. The occurrence of canopy gaps on a global scale is mainly driven by lightning strikes, and precipitation of the coldest quarter, while their density is driven by lightning strikes, the precipita-tion of the wettest and driest months, and the maximum temperature of the warmest month. Overall, these climatic factors have the potential to act synergistically thus contributing to canopy gap occurrences and density within a given mangrove forest patch. On a local scale, the thesis showed clustered spatiotemporal patterns in South Africa’s largest mangrove forest at uMhlathuze (80% of the total mangrove coverage in the country) near Rich-ards Bay. Beachwood canopy gaps primarily exhibited random patterns with some spatial cluster-ing, along with random temporal patterns. The patterns at both sites support the hypothesis that lightning strikes, insects or pathogen attacks or competition potentially contribute to canopy gap formation. Spatial distribution of canopy gaps was linked to high canopy at both uMhlathuze and Beachwood, supporting the lightning strikes hypothesis. Canopy gaps at uMhlathuze remained open for at least 23 years. In contrast, no canopy gap at Beachwood had closed over the time span of 18 years that the study covers. These findings highlight the need for active (re-)establishment of canopy gaps, as the very slow natural regeneration might result in loss of valua-ble ecosystem services provided by mangroves, such as carbon sequestration and long-term stor-age of carbon. Furthermore, the canopy gap closure dynamics and factors influencing their closure across 10 countries and two biogeographical realms—the Atlantic East Pacific and Indo West Pacific were investigated. At higher latitudes above the equator a pattern of relatively shorter canopy gap clo-sure durations and increased annual percentage of canopy gap closure was observed. Approxi-mately 70-100% of the canopy gaps had undergone closure in eight countries. Conversely, during the timeframe encompassed by the study, over 70% of the canopy gaps in Australia exhibited a persistent lack of closure for at least 18 years. Canopy gap closure duration was found to be sig-nificantly influenced by the mean temperature of the wettest quarter of the year. Similarly, the annual percentage of canopy gaps closing was significantly influenced by mean temperature of the wettest quarter, mean temperature of the driest quarter, pH, and salinity. This highlights the potential impact of climatic environmental parameters on canopy gap closure dynamics. The thesis emphasizes the significance of prioritizing the (re-)establishment of mangrove forest areas with non-closing gaps. This is crucial for ensuring the integrity of long-term carbon storage, coastal protection, habitats for diverse fauna, and a sustainable timber supply that supports local livelihoods under climate change. Overall, this thesis contributes to providing baseline data on mangrove areas with canopy gaps and their potential drivers, both globally and on regional and local scales. It highlights the factors influencing canopy gap closures and mangrove areas facing a lack of regeneration, emphasizing the urgent need for human assistance in (re-)establishing those canopy gaps.Dissertation412 272 - Some of the metrics are blocked by yourconsent settings
Item-typ:Veröffentlichung, Significance of intraspecific variation for decomposition processes(2021-10-15); ; ; Over the last decades a growing awareness for the role of biodiversity in an ecological context has grown. Species richness and functional diversity have been found to influence ecosystem processes like production and decomposition. In the context of decomposition mainly the diversity of the decaying litter has been in the focus of interest – and (like for other studies on diversity) mainly interspecific diversity. As the concept of biodiversity shifted from "number of species" towards “functional diversity”, intraspecific variation was more and more recognized as a potentially significant level of biodiversity. However, very little is known about the influence of intraspecific variation and diversity in the context of decomposition and up to now, nothing is known regarding the ecological role of this level of diversity in a detritivore species in the context of decomposition. Consequently, the aim of this thesis was to study the influence of intraspecific variation in a detritivore species on consumption and on decomposition of different litter mixes. To test if an increased diversity within such a detritivore species results in a higher consumption, isopods of the species Porcellio scaber from several European populations were combined into artificial groups of three different diversity-levels. Groups were tested with newly developed genetic markers to confirm differences in diversity and fed on different leaf litter species and litter mixtures with different levels of interspecific diversity in a microcosm-experiment. A positive effect of intraspecific diversity on litter consumption only occurred in single litter treatments, but – other than expected – not in litter mixtures. However, these effects were considerably lower than the also measured “mixed litter effects” (effects of increased interspecific litter diversity). In addition to the results (due to the developed genetic marker) some insights about the variation and population differentiation of the widely distributed Isopod species P. scaber were be gained. To test the effect of an (expected) decreased diversity on consumption, two populations of the Isopod Trachelipus ratzeburgii (Brandt 1833, Isopoda, Oniscidea) living on two different altitudes of the same mountain were fed on different leaf litter species and litter mixtures – hypothesizing that the fluctuation in environmental parameters like temperature at high altitude reduced the diversity in a high-altitude population. In addition, genetic variation within and differentiation between both populations was tested and stress resistance (via HSP70-expression) was measured to see if a reduced variation goes along with an increased level of stress resistance due to positive selection towards this trait. However, results show that the chosen populations did not differ in variation (along with being not differentiated) and had no differences in stress resistance. They also did not differ in absolute consumption, despite a strong difference in size, as the isopods from high altitude were much smaller than those from the low altitude population. The reasons for this difference remain unknown, but these findings show a high plasticity for this species. As consumption rate is only one element of the direct and indirect influences detritivores have on decomposition, the variation in digestion of P. scaber was measured in an additional approach. Animals from several populations were fed with standardized food, whereafter the chemical structure of the feces was compared using Pyrolysis-GC-MS. The isopods showed (also in comparison to specimen of other Oniscidea species) a substantial amount of variation in the chemical fingerprint of the feces, whereas the differences could only partly be explained by genetic proximity. Other factors, such as the microbiome of the digestive tract, appear to have an additional influence. In summary, the results provide indications of an importance of intraspecific variation and diversity for decomposition processes, but its influence was (with respect to consumption of leaf litter) considerably less strong compared to the influence of the interspecific variation of the leaf litter. Nevertheless, the results show in many respects that intraspecific variation (and plasticity) should not be neglected in the context of decomposition.Dissertation311 323 - Some of the metrics are blocked by yourconsent settings
Item-typ:Veröffentlichung, Tracing organic matter in a tropical estuary, Jaguaripe River, Brazil - Implications of its origin and distribution(2024-08-13); ; ; Tropical estuarine systems are important links between terrestrial and marine realms. Large amounts of organic matter (OM) originating from a variety of sources are transported through them. OM that enters estuarine waters as suspended particulate organic matter (SPOM) settles either in estuarine systems and becomes part of the sediment organic matter (SOM) pool or is transported through the estuary and eventually reaches marine waters. Both SPOM and SOM are degraded and transformed by biochemical processes over time in estuarine waters. As a result, OM is converted to dissolved organic matter (DOM), which is the third form of OM present in estuarine systems that has been investigated in this thesis. Until today, tracking the movement of OM in estuarine systems remains challenging because all three forms of OM are subject to different drivers that shape their dynamics. A crucial part of better understanding complex OM dynamics in estuarine systems is identifying the composition of OM sources contributing to their respective OM pools. Many methods applied in the literature to trace OM sources, such as stable isotope-based mixing models, are limited in which sources can effectively be differentiated. Thus, this thesis presents the novel analytical approach of pyrolysis gas chromatography-mass spectrometry (Py-GC-MS) to identify sources contributing to OM pools in a tropical estuarine system. The newly developed bioinformatics pipeline for data processing as the basis allowed us to trace OM sources in SPOM and SOM pools. Py-GC-MS analysis was used in comparison with the well-established approach of stable isotope-based mixing models to access OM source contributions to SOM pools within mangrove forests bordering the Jaguaripe River estuary, Bahia, Brazil. This comparison revealed clear advantages of Py-GC-MS analysis over stable isotope analysis for accessing the composition of SOM pools with a variety of potential OM source groups present. A strong relationship was found between mangrove SOM and OM derived from terrestrial plants. This relationship indicates a strong OM influx through the Jaguaripe River into the mangrove sediments. Additionally, different contribution levels of coastal pelagic OM (representing OM from mainly pelagic phyto-, zooplankton) to the SOM pools in mangrove forests between seasons were revealed. This indicates OM inputs to SOM pools in mangrove forests to be influenced by a combination of riverine and tidal water-driven water movements alike. Compositional differences in OM source contributions were investigated for SPOM and SOM pools along the middle to lower Jaguaripe River estuary using Py-GC-MS. Coastal pelagic OM dominated the contributions to SPOM. Mangrove-derived OM was only detected in SPOM samples collected during the rainy season which is likely related to an increased import of OM particles from mangroves into estuarine waters by surface runoff. Compositional differences between OM sources contributing to SOM pools along the estuary showed clear differences between the middle and lower estuary. Sediments from the middle estuary showed strong OM contributions from terrestrial plants and mangroves. In contrast, sediments from the lower estuary had higher contributions of macroalgae-derived and coastal pelagic OM. OM contributions from terrestrial plants and mangroves detected further downstream during the rainy season indicated shifting dynamics of water movement between seasons. Shifts between seasons are likely linked to changing water discharge rates through the Jaguaripe River. Additionally, thermal stability analysis revealed increased levels of SOM degradation downstream along the estuary, which was not the case for SPOM. This pattern of SOM stability along the estuary is indicative of the turbulent flow regimes at the bottom of the estuary that shape its fate. SOM is frequently re-suspended from the bottom of the subjecting it further degradation. This re-suspension is caused by interactions between tidal and riverine water movements causing turbulent forces near the bottom of the estuary. Differences in DOM compositions along the middle and lower estuaries of the Jaguaripe River were analysed using Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS). Overall, elevated organic carbon concentrations along the middle estuary fringed by mangrove forests suggest they are an important source of DOM to the estuarine waters. Elevated concentrations of sulphur-containing compounds and saturated compounds with low O/C ratios, which are both strongly associated with OM transformation processes by sulphur-reducing bacteria in OM-rich and anoxic sediments, were detected along the middle estuary during the dry season. Depletion of total dissolved nitrogen (TDN) and nitrogen-containing aliphatic compounds in DOM pools indicate processes of increased nitrogen removal within mangroves during the wet season. These two observed differences revealed seasonally shifting DOM dynamics, with mangroves being sources of sulphur-containing compounds in one season and a sink for nitrogen in the other. Modeling of tracing indices for terrigenous, mangrove porewater-derived- and mangrove leaf-leached OM showed additional evidence of seasonal shifts of DOM dynamics along the estuary. These results further strengthened the hypothesis that riverine water flow and tidal movements are the strongest drivers shaping DOM dynamics in the Jaguaripe River estuary. This work contributes to a better understanding of DOM transport within and beyond the estuary boundaries and the potential drivers behind it. Water movements driven by tidal forces and riverine discharge rates were both indicated to strongly affect OM transport along and across the tropical estuary of the Jaguaripe River. The results further imply a highly complex interplay of tidal movements and river flow regimes. The basic findings of these in combination with identified contribution levels of different OM sources allowed for a better understanding of how human activities could affect them in the future. Tropische Ästuarsysteme sind wichtige Bindeglieder zwischen terrestrischen und marinen Systemen. Durch sie werden große Mengen an organischem Material (OM) transportiert, das aus verschiedenen Quellen stammt. Organische Stoffe, die als suspendiertes partikuläres organisches Material (SPOM) in die Ästuargewässer gelangen, setzen sich entweder im Ästuar ab, wo sie Teil des sedimentären organischer Material (SOM) werden, oder werden in der Wassersäule durch das Ästuar schließlich die marinen Küstengewässer transportiert. Sowohl SPOM als auch SOM werden im Laufe der Zeit durch biochemische Prozesse in den Gewässern des Ästuars abgebaut und umgewandelt. Infolgedessen wird OM in gelöste organische Material (DOM) umgewandelt, die dritte Form von OM in Ästuarsystemen, die in dieser Arbeit untersucht wurde. Bis heute ist es schwierig, die Bewegung von OM in Ästuarsystemen zu verfolgen, da alle drei Formen von organischer Substanz unterschiedlichen Faktoren unterliegen, die ihre Dynamik beeinflussen. Um die komplexe OM-Dynamik in Ästuarsystemen besser zu verstehen, ist es von entscheidender Bedeutung, die Zusammensetzung der OM-Quellen zu ermitteln, die zu ihren jeweiligen OM-Bestand beitragen. Viele in der Literatur angewandte Methoden zum Aufspüren von OM-Quellen, wie z. B. Mischungsmodelle auf der Grundlage stabiler Isotopenanalysen, sind nur begrenzt in der Lage, Quellen effektiv zu differenzieren. Daher wird in dieser Arbeit der moderne analytische Ansatz der Pyrolyse-Gaschromatographie-Massenspektrometrie (Py-GC-MS) vorgestellt, um Quellen zu identifizieren, die zu OM-Beständen in einem tropischen Ästuarsystem beitragen. Die neu entwickelte Bioinformatik-Pipeline für die Datenverarbeitung als Grundlage ermöglichte es uns, OM-Quellen aus SPOM und SOM-Beständen zu ermitteln. Py-GC-MS-Analyse wurden mit dem etablierten Ansatz der auf stabilen Isotopen basierenden Mischungsmodelle verglichen, um die Beiträge der OM-Quellen zu den SOM-Beständen in den Mangrovenwäldern am Ästuar des Jaguaripe Flusses in Bahia, Brasilien, zu ermitteln. Dieser Vergleich ergab eindeutige Vorteile der Py-GC-MS-Analyse gegenüber der Analyse stabiler Isotope, um die Zusammensetzung von SOM-Bestände mit einer Vielzahl potenzieller OM-Quellengruppen zu ermitteln. Es wurde eine enge Beziehung zwischen der Mangroven-SOM und der von Landpflanzen stammenden OM festgestellt. Diese Beziehung deutet auf einen starken OM-Zufluss durch den Jaguaripe-Fluss in die Mangrovensedimente hin. Darüber hinaus wurde festgestellt, dass die pelagische OM der Küste (OM von hauptsächlich pelagischem Phyto- und Zooplankton) je nach Jahreszeit unterschiedlich stark zu den SOM-Bestände in den Mangrovenwäldern beiträgt. Dies deutet darauf hin, dass der OM-Eintrag in die SOM-Bestände in den Mangrovenwäldern durch eine Kombination aus fluss- und gezeitenbedingten Wasserbewegungen gleichermaßen beeinflusst wird. Die Unterschiede in der Zusammensetzung der OM-Quellen wurden für SPOM- und SOM-Bestände entlang des mittleren bis unteren Jaguaripe-Ästuars mittels Py-GC-MS untersucht. OM aus pelagischen Küstensystemen dominierte die Beiträge zu SPOM. Aus den Mangroven stammendes OM wurde nur in SPOM-Proben nachgewiesen, die während der Regenzeit gesammelt wurden, was wahrscheinlich auf einen erhöhten Import von OM-Partikeln aus den Mangroven in das Ästuarwasser durch Oberflächenabfluss von Regenwasser zurückzuführen ist. Die Unterschiede in der Zusammensetzung der OM-Quellen, die zu den SOM-Bestände entlang des Ästuars beitragen, zeigten deutliche Unterschiede zwischen dem mittleren und unteren Ästuar. Sedimente aus dem mittleren Ästuar wiesen starke OM-Beiträge von Landpflanzen und Mangroven auf. Im Gegensatz dazu wiesen die Sedimente des unteren Ästuars höhere Beiträge von aus Makroalgen und aus pelagischen Küstensystemen stammenden OM auf. OM-Beiträge von Landpflanzen und Mangroven, die während der Regenzeit weiter stromabwärts nachgewiesen wurden, deuten auf eine sich verändernde Dynamik des OM-Transports zwischen den Jahreszeiten hin. Die Verschiebungen zwischen den Jahreszeiten hängen wahrscheinlich mit den sich ändernden Wasserabflussraten durch den Jaguaripe-Fluss zusammen. Darüber hinaus ergab die Analyse der thermischen Stabilität, dass die SOM flussabwärts entlang des Ästuars zunehmend abgebaut wird, was bei der SPOM nicht der Fall war. Dieses Muster der SOM-Stabilität entlang des Ästuars ist ein Hinweis auf die turbulenten Strömungsverhältnisse am Boden des Ästuars, die das Schicksal der SOM bestimmen. SOM wird häufig vom Grund des Ästuars wieder aufgewirbelt, wodurch es weiter abgebaut wird. Diese Resuspension wird durch Wechselwirkungen zwischen Gezeiten- und Flusswasserbewegungen verursacht, die in der Nähe des Ästuars turbulente Kräfte erzeugen. Die Unterschiede in der DOM-Zusammensetzung im mittleren und unteren Mündungsgebiet des Jaguaripe Flusses wurden mit der Fourier-Transformations-Ionenzyklotronresonanz-Massenspektrometrie (FT-ICR-MS) analysiert. Die erhöhten Konzentrationen an organischem Kohlenstoff im mittleren Mündungsgebiet, das von Mangrovenwäldern gesäumt wird, deuten darauf hin, dass diese eine wichtige Quelle von DOM für das Ästuarwasser darstellen. Erhöhte Konzentrationen von schwefelhaltigen Verbindungen und gesättigten Verbindungen mit niedrigem O/C-Verhältnis, die beide stark mit OM-Umwandlungsprozessen durch schwefelreduzierende Bakterien in OM-reichen und anoxischen Sedimenten in Verbindung gebracht werden, wurden entlang des mittleren Ästuars während der Trockenzeit festgestellt. Der Rückgang des gesamten gelösten Stickstoffs (TDN) und der stickstoffhaltigen aliphatischen Verbindungen in den DOM-Bestände deutet auf Prozesse des verstärkten Stickstoffabbaus in den Mangroven während der Regenzeit hin. Diese beiden beobachteten Unterschiede zeigen, dass sich die DOM-Dynamik jahreszeitlich verschiebt, wobei die Mangroven in der einen Jahreszeit Quellen für schwefelhaltige Verbindungen und in der anderen eine Senke für Stickstoff sind. Die Modellierung von Tracer-Indizes für terrigenes, aus dem Porenwasser der Mangroven stammendes und von Mangrovenblättern ausgelaugtes OM lieferte zusätzliche Hinweise auf jahreszeitliche Verschiebungen der DOM-Dynamik entlang des Ästuars. Diese Ergebnisse untermauern die Hypothese, dass der Flusslauf und die Gezeitenbewegungen die stärksten Triebkräfte für die DOM-Dynamik im Ästuar des Jaguaripe-Flusses sind. Diese Arbeit trägt zu einem besseren Verständnis des OM-Transports innerhalb und über die Grenzen des Ästuars hinaus und der potenziellen Triebkräfte dafür bei. Es wurde festgestellt, dass sowohl die gezeitenbedingten Wasserbewegungen als auch die Abflussraten der Flüsse den OM-Transport entlang und über das tropische Ästuar des Jaguaripe-Flusses hinweg stark beeinflussen. Die Ergebnisse deuten außerdem auf ein äußerst komplexes Zusammenspiel von Gezeitenbewegungen und Flussabflussregimen hin. Diese grundlegenden Erkenntnisse in Kombination mit den ermittelten Beiträgen der verschiedenen OM-Quellen ermöglichen ein besseres Verständnis der möglichen künftigen Auswirkungen menschlicher Aktivitäten auf diese.Dissertation105 81