In the tidal inlet between the East Frisian islands of Langeoog and Spiekeroog, southern North Sea, a timeseries station was set up in autumn 2002 as part of the research programme BioGeoChemistry of Tidal Flats run by the University of Oldenburg. The purpose of the station is to provide continuous data on physical, biological and chemical parameters. In addition to instruments recording basic hydrographic and meteorological parameters, the time-series station is equipped with acoustic Doppler profilers for measuring surface waves and current profiles. Compact optical spectrometers are being used for spectral measurements of seawater transmission and for daylight reflectance. Additional sensors were installed for measuring oxygen, nutrients and methane in the seawater. The data shall help to quantify the flux of dissolved and suspended matter between the backbarrier tidal flat and the open sea and to characterise the material transformation in the tidal flat area by biogeochemical processes over the tidal cycle. Due to its novel design, operation of the station is also possible during winter and under extreme weather conditions (gales, storm surges, and sea ice) when data sampling with conventional platforms such as research vessels, buoys, or smaller poles could not be performed in the past. In this way, time series of data are obtained, which include events that are most relevant to the evolution of this coastal area. The performance of the station and its equipment are presented with data covering 6 years of operation. Time series of air and water temperature as well as seawater salinity demonstrate the multiyear dynamics of these parameters in the East Frisian Wadden Sea. Hydrographic data collected under specific meteorological conditions such as gales and storm surges exemplify the all-weather capabilities of the station and its value for studying hydrographic processes in the Wadden Sea.

The spatial and temporal distributions of chromophoric dissolved organic matter (CDOM) and dissolved organic carbon (DOC) was studied in the East-Frisian Wadden Sea (Southern North Sea) during several cruises between 2002 and 2005. The spatial distribution of CDOM in the German Bight shows a strong gradient towards the coast. Tidal and seasonal variations of dissolved organic matter (DOM) identify freshwater discharge via flood-gates at the coastline and pore water efflux from tidal flat sediments as the most important CDOM sources within the backbarrier area of the Island of Spiekeroog. However, the amount and pattern of CDOM and DOC is strongly affected by various parameters, e.g. changes in the amount of terrestrial run-off, precipitation, evaporation, biological activity and photooxidation. A decoupling of CDOM and DOC, especially during periods of pronounced biological activity (algae blooms and microbial activity), is observed in spring and especially in summer. Mixing of the endmembers freshwater, pore water, and open sea water results in the formation of a coastal transition zone. Whilst an almost conservative behaviour during mixing is observed in winter, summer data point towards nonconservative mixing.

Coastal observatories are key to improve the understanding of processes within the coastal area and their interactions with regional and global environmental changes. The land-sea transition zone is an essential area that allows research on unique scientific questions under anthropogenic and natural influences. Amid the Wadden Sea UNESCO world natural heritage site – the largest tidal flat region worldwide – the barrier island Spiekeroog is an excellent location for an observatory studying land-sea interactions. The integrated Spiekeroog Coastal Observatory (SCO) operated by the Institute for Chemistry and Biology of the Marine Environment (ICBM, University of Oldenburg) is dedicated to interdisciplinary marine and terrestrial ecosystem research. Its position within the tidal area and the multitude of research-field addressed establishes the SCO as a unique coastal observatory with the potential to identify patterns in long-term variability and simultaneously understanding short-term changes. The establishment of the Time-Series Station (TSS) Spiekeroog in a tidal channel west of Spiekeroog back in 2002 laid the foundation of the SCO. Since then, the observatory is expanding continuously and is now representing a valuable asset supporting education, industry, government, and environmental conservation efforts in the area. Summing up the infrastructure and technical components, the importance of the SCO is evident, and individual projects greatly benefit from the collaboration with the partners in and the elements of the SCO. Harmonizing the infrastructure and competences of contributing partners will be a next step to further consolidate the SCO. A challenge poses the maintenance of the SCO based on projects, which is focused on the addition of new facilities, not maintaining, refurbishing, or (if necessary) deconstructing existing infrastructure. Therefore, structural support and funding opportunities not linked to projects but aiming to sustain observational capacities are required.

The paper is one of the series of papers about the Advisory Monitoring System for controlling the fatigue lifetime consumption of FPSO hulls. The system has been developed within the Monitas Joint Industry Project (JIP). The name Monitas stands for Monitoring Advisory System. A key factor for proper lifetime prediction is an accurate assessment of the ocean surface wavefield. Therefore, a dedicated wave system analyses tool (XWaves) has been developed within the project that allows for online analysis of the measured wave data. The Monitas project recommends use of navigational radar for measuring waves. This paper compares the wave data obtained from such radar with that obtained from a wave buoy. The differences in obtained wave data from both instruments are illustrated and explained. The effect of these differences on fatigue lifetime consumption has been quantified. The paper also investigates how different wave data formats which are being used by the offshore industry affect the fatigue lifetime calculations. All comparisons and conclusions are based on real data collected from the Monitas system installed on board FPSO Glas Dowr. It has been concluded that navigational radar can be used as the instrument for wave measurements and that different wave data formats are acceptable providing the wave directionality data is preserved.

The paper is one of the series of papers about the Advisory Monitoring System for controlling the fatigue lifetime consumption of FPSO hulls. The system has been developed within the Monitas Joint Industry Project (JIP). The name Monitas stands for Monitoring Advisory System. A key factor for proper lifetime prediction is an accurate assessment of the ocean surface wavefield. Therefore, a dedicated wave system analyses tool (XWaves) has been developed within the project that allows for online analysis of the measured wave data. The Monitas project recommends use of navigational radar for measuring waves. This paper compares the wave data obtained from such radar with that obtained from a wave buoy. The differences in obtained wave data from both instruments are illustrated and explained. The effect of these differences on fatigue lifetime consumption has been quantified. The paper also investigates how different wave data formats which are being used by the offshore industry affect the fatigue lifetime calculations. All comparisons and conclusions are based on real data collected from the Monitas system installed on board FPSO Glas Dowr. It has been concluded that navigational radar can be used as the instrument for wave measurements and that different wave data formats are acceptable providing the wave directionality data is preserved.