Description: The impact of ocean acidification on benthic habitats is a major preoccupation of the scientific community. However, the natural variability of pCO2 and pH in those habitats remains understudied, especially in temperate areas. In this study we investigated temporal variations of the carbonate system in nearshore macrophyte meadows of the western Baltic Sea. These are key benthic ecosystems, providing spawning and nursery areas as well as food to numerous commercially important species. In situ pCO2, pH (total scale), salinity and PAR irradiance were measured with a continuous recording sensor package dropped in a shallow macrophyte meadow (Eckernförde bay, western Baltic Sea) during three different weeks in July (pCO2 and PAR only), August and September 2011.The mean (± SD) pCO2 in July was 383±117 µatm. The mean (± SD) pCO2 and pHtot in August were 239±20 µatm and 8.22±0.1, respectively. The mean (± SD) pCO2 and pHtot in September were 1082±711 µatm and 7.83±0.40, respectively. Daily variations of pCO2 due to photosynthesis and respiration (difference between daily maximum and minimum) were of the same order of magnitude: 281±88 µatm, 219±89 μatm and 1488±574 µatm in July, August and September respectively. The observed variations of pCO2 were explained through a statistical model considering wind direction and speed together with PAR irradiance. At a time scale of days to weeks, local upwelling of elevated pCO2 water masses with offshore winds drives the variation. Within days, primary production is responsible. The results demonstrate the high variability of the carbonate system in nearshore macrophyte meadows depending on meteorology and biological activities. We highlight the need to incorporate these variations in future pCO2 scenarios and experimental designs for nearshore habitats.

Description: Dissolved greenhouse gas measurements (GHG) are of increasing importance for science, monitoring agencies and industry. Sensors for dissolved carbon dioxide (CO2) and methane (CH4) are applied in a growing number of applications. At the same time the number of mobile platforms deployed in the field is growing. Modern mobile platforms can sample on spatial and temporal scales that previously were not easily accessible thereby providing cost efficient data. Furthermore a trend towards the interconnection of mixed platforms and sensors is recognizable. The connection between these trends is discussed on the basis of sensor integrations into platforms. An approach between sensor and platform manufacturers becomes necessary to achieve an intelligent combination of contemporary measuring devices and their carriers as well as to make the adaptations on both sides efficient. Instruments of the HydroC™ family were successfully deployed on versatile stationary and mobile platforms, such as AUVs and floats. Platform and application demands for the deployment of dissolved gas sensors on diverse platforms are discussed. Fields of improvement for the instruments are identified to make them more versatile and access further platforms in the future.

Description: The report analyses the interactions between the public and private organisations involved in the project activities as members of the project consortium, internal advisory boards and stakeholders. This strong, collaborative and interdisciplinary collaboration between public and private sectors is essential to improve ocean observing and forecasting systems with innovative technological solutions also in support of the implementation process of important global strategies related to the ocean.