Description: The firn densification model IMAU-FDM has been used to simulate the firn density profile around Antarctica. The model is forced at the surface with climate data from the RACMO2.3 regional climate model. Here we provide the depth of three key firn density layers below the surface (750, 800 and 830 kgm^-3), averaged over the period 1979-2013. The data is on a horizontal grid of 27x27 km. The depth of each of these density layers was then subtracted from the surface elevation provided by Bedmap2 to determine where permeable firn exists below sea level. This defines the "brine zone" - the region where seawater may infiltrate the firn layer. We also provide shapefiles mapping the brine zone for each of three stated densities.

Description: This data collection contains data on dissolved phosphorus species (TDP – total dissolved phosphorus; DIP or SRP – dissolved inorganic phosphorus or soluble reactive phosphorus; DOP – dissolved organic phosphorus) and particulate phosphorus species (POP-particulate inorganic phosphorus; PIP – particulate organic phosphorus; TPP – Total particulate phosphorus) at Sylt Roads LTER (2000-2016), Wadden Sea, North Sea.

Description: Due to changing temperature regimes in the North- and the Wadden Sea, the fish survey in the Sylt Rømø bight (SRB) was established in 2007 to investigate the Wadden Sea fish fauna with special interest in changes of migration behavior, species composition and feeding habits. Seven stations were sampled monthly inside the SRB. Two additional stations, one outside the bight, one close to the Danish border were sampled as references four times a year. For sampling a mini bottom trawl, total length 17 m, trawl opening 7 m, height 3 m with a mesh size of 36 mm in the wings, 16 mm in the mid part and 6 mm in the cod end was used. At every station one haul in the water column and another at the bottom were sampled, for 15 minutes at a speed of approximately 2 knots. The data help to get more detailed insight of food chains and energy flows in the Wadden Sea area. This compilation gives an overview of all datasets from the SRB fish survey for the period 2007 to 2020.

Description: The SYLT ROADS LTER pelagic time series covers physical and hydrochemical parameters in the Sylt-RØmØ Bight, Wadden Sea, North Sea. Since its inception in 1973 Sea Surface Temperature (SST), Salinity, Ammonia, Nitrite, Nitrate, Soluble Reactive Phosphorus (SRP) and Silicate were measured on a biweekly basis. The other parameters were introduced later (pH - since 1979, dissolved organic nitrogen (DON) - since 1996, dissolved organic phosphorus (DOP) - since 2001, chlorophyll a - since 1979, suspended particulate matter (SPM) - since 1975) and in case of dissolved oxygen were discontinued (1979-1983). During the years 1977, 1978 and 1983 no sampling took place. Since the start of continuous sampling in 1984 the sea surface temperature in the bight has risen by 1.16 oC, with the highest increases during the fall months while the pH decreased by 0.248 units. Summer and fall salinities are generally significantly elevated compared to spring and winter conditions. Dissolved nutrients as ammonia, nitrite, nitrate and reactive phosphorus (SRP) showed periods of elevated eutrophication (1973 – 1998) while silicate displayed a different development with significantly elevated levels of the winter data since 1999. Interestingly phytoplankton sum parameters did not mirror these huge nutrient changes, as a seasonal comparison of the two eutrophication conditions showed no significant differences with regard to chlorophyll, which is ultimately triggered by an important change in nutrient limitation during the time series: Till 1988 the phytoplankton was primarily limited by silicate, while since 1999 SRP limitation became increasingly important.