David Kaiser

Helmholtz-Zentrum Hereon | HZG · Global Coast

Mangroves serve as either sinks or sources for inorganic and organic nutrients and can mitigate anthropogenic nutrient pollution, control the production in adjacent systems, and prevent eutrophication. To better understand the nutrient dynamics in a subtropical mangrove we employed a three-way approach in the Nanliu River Estuary, southern China: P...

Mangroves are often presented as NbS for, among others, Blue Carbon. However, a lack of locally relevant data makes ecosystem service estimates highly uncertain, and outcomes do not always benefit local traditional rights holders. In coastal Ghana, mangroves remain understudied but overexploited because a value chain centered on firewood provides l...

Coastal hazards such as erosion, flooding, and pollution are major challenges facing many coastal areas of Ghana. In response to these challenges, the concept of Nature-based Solutions that has gained prominence globally has been proposed to address these challenges in the Ghanaian coast. While mangroves have the potential as a Nature-based Solutio...

In 2018, Europe experienced an unprecedented heatwave and drought, especially in central and northern Europe, which caused decreased terrestrial production and affected ecosystem health. In this study, the effects of this event on the marine environment are investigate, with a focus on the biogeochemical response in the German Bight of the North Se...

In 2018, Europe experienced an unprecedented heatwave and drought, especially in central and northern Europe, which caused decreased terrestrial production and ecosystem health. The effects on the marine environment are yet unclear. Here we investigate the biogeochemical response to the event in the German Bight of the North Sea. Using time series...

Coastal hazards such as erosion, flooding and pollution are major problems globally, exacerbated by increasing frequency and severity of hydro-meteorological extremes amidst inadequate technology and adaptive capacity. The Ghanaian coast is an example of a region impacted by such problems. Factors hampering the management and improvement of these i...

Plastics and microplastics increasingly gain importance due to their perils and wide distribution in the marine environment. Microfibers account for the largest percentage of anthropogenic-induced microparticles, which inter alia, consist of plastic, and are found in deep-sea sediments. However, the sinking of fibers from the surface through the wa...

Particle flux material collected in 2000 m depth in the Northeast Atlantic at 33°N and 22°W was analyzed for trace metals and persistent organic pollutants. Element enrichment factors relative to lithogenic Al were elevated indicating possible anthropogenic contributions for all trace metals except V. Polycyclic aromatic hydrocarbons, polychlorinat...

Sinking experiments were conducted using irregularly shaped polyamide (PA), polymethyl methacrylate (PMMA), and polyethylene terephthalate (PET) particles sized 6 to 251 μm. Certified PS spheres were used to validate experiments and showed that the effect of particle size on terminal sinking velocity is well reproduced by the method. As expected si...

We investigated the concentration distribution and composition of organic pollutants in sediments of the shelf and the deep northern South China Sea (NSCS). Concentrations of polycyclic aromatic hydrocarbons (Σ 15 PAH; 10.69-66.45 ng g −1), Dichlorodiphenyltrichloroethane (Σ 4 DDT; 0-0.82 ng g −1), and polychlorinated biphenyls (Σ 24 PCB; 0-0.12 ng...

Although plastic is ubiquitous in marine systems, our current knowledge of transport mechanisms is limited. Much of the plastic entering the ocean sinks; this is intuitively obvious for polymers such as polystyrene (PS), which have a greater density than seawater, but lower density polymers like polyethylene (PE) also occur in sediments. Biofouling...

We studied organic matter in the central Black Sea and its northeastern and northwestern shelf break within three weeks in November 2013 to test the hypothesis that in situ production could explain lateral and vertical variability in its composition and distribution. The wide spatial coverage over a short period of time achieved during this study r...

In summer 2016 we incubated microplastic particles at coastal station Heiligendamm and estuarine station IGA Park (Germany) for 14 weeks. SEM images were produced to illustrate the growth of a natural biofilm on the surface of the particles.

Poster for internal evaluation.

Microplastics are ubiquitous in marine environments, including in sediments. Knowing their distribution behavior is important to discern where they might harm benthic organisms. Particles denser than water, e.g. polystyrene (PS), naturally sink through the water column. Also plastic that should float, such as polyethylene (PE), is found in sediment...

The Beibu Gulf, the northwestern part of the South China Sea, is a shallow shelf sea. Its rapid economic development increases livelihood while threatening ecosystems along the Chinese coast. Nevertheless, the degree and effects of pollution have attracted little scientific attention. Against this background we aim to establish a history and baseli...

Sediment cores from the central Beibu Gulf and its northern coastal mangroves were analyzed for polycyclic aromatic hydrocarbons (PAH), the organo-chlorine pesticides dichlorodiphenyltrichloroethane (DDT) and hexachlorobenzene (HCB), and polychlorinated biphenyls (PCB), to reconstruct the organic pollution history of developing south-west China. Re...

Surface sediments from the central and coastal Beibu Gulf, southern China, were analyzed for persistent organic pollutants. The absence of polychlorinated biphenyls (PCB; generally below detection limit), low concentrations of polycyclic aromatic hydrocarbons (PAH; 24–647 ng g−1), and locally high contamination with organo-chloro pesticides (DDT; 0...

CLAWAR 2015: 18th International Conference on Climbing and Walking Robots and the Support Technologies for Mobile Machines Zhejiang University, HangZhou, China, 6 – 9 September 2015 Edited by: Hongye Su ( Zhejiang University, China), Tianmiao Wang ( Beijing University of Aeronautics and Astronautics, China), Mohammad O Tokhi ( University of Sheffie...

The poster describes similarities and differences of the effects aquaculture effluents have on the nitrogen composition in estuarine waters of two sites in southern China

Persistent organic pollutants are principally anthropogenic toxic compounds ubiquitously found in coastal marine sediments. As different compound classes derive from industrial and agricultural activities, we seek to investigate their composition, transport pathways, and potential toxicities in a developing region of southern China. Surface sedimen...

Biogeochemical sampling, sediment pore water profiles and sediment incubations, as well as budget and hydrodynamic model calculations reveal that in the subtropical macrotidal Nanliu Estuary, southern China, agriculture and aqauculture-derived nitrogen inputs strongly exceed nitrogen removal capacity by estuarine biogeochemisty and only tidal expor...

This study investigates the physical conditions (water depth, current speed, salinity, temperature) in Lianzhou Bay, a shallow coastal bay in southern China, during two expeditions in the dry and wet seasons of 2011. Based on these expedition data, basic hydrodynamic parameters like Brunt-Väisälä Frequency, Richardson Number, Rossby radius, and Res...

Anthropogenic nutrients, mainly from agriculture but also from aquaculture, cause eutrophication. Negative effects include ecosystem degradation via oxygen depletion following organic matter decomposition. Mangrove forests are potential nutrient filters. This study investigates land-derived material inputs into coastal waters of southern China and...

Human watershed activities like agriculture and aquaculture often increase dissolved inorganic nitrogen (DIN) input to estuaries and enhance eutrophication. High DIN loading is accompanied by elevated nitrogen isotope signatures (?15N) which, too, have been related to anthropogenic perturbation. To assess anthropogenic nutrient inputs and their dis...

Inputs from agriculture, urbanization and aquaculture alter land-sea fluxes of nutrients and organic matter, and induce major environmental problems. Against this background we have investigated the Nanliu River (NR) in Guangxi Province, SW China. This subtropical river drains an area of 9704 km2 and discharges an average of 166 m3 s-1 into the Bei...

Mangrove forests can serve as either sinks or sources for different inorganic and organic nutrients. These processes can mitigate anthropogenic nutrient pollution and control the production in adjacent systems, preventing eutrophication. To investigate the seasonality of nutrient uptake capabilities of sediments in a subtropical estuarine mangrove...

Tropical seagrass beds are systems of high primary productivity that support secondary production via grazing and detrital food chains. Epiphytes growing on the leaves of seagrass plants can account for high proportions of the primary production in these ecosystems. The effect of epiphytes on seagrass plants is not definite but is generally assumed...