Thorsnes, Terje; Bøe, Reidulv; Diesing, Markus (2022): Physical properties of sediments in the Norwegian Trough measured on short cores taken between 1992 and 1996 [dataset]. PANGAEA, https://doi.org/10.1594/PANGAEA.942437

Wet bulk density, dry bulk density, porosity, water content and water saturation of sediments from the Norwegian Trough were determined on short cores taken between 1992 and 1996. On the cruises 17-25 July 1992 (station 2-55) and 1-6 July 1993 (station 56-75) in the easternmost part of the Skagerrak, cores were taken with a Niemistö corer. Plastic liners (length 76 cm, outer diameter 63 mm, inner diameter 59 mm) were placed in the corer with holes drilled every five centimetres downwards. These holes were sealed with tape before sampling. After the sample was taken, the tape was removed. In most cases, there was water along the inside of the plastic liner. This water was allowed to drain before sub-samples were taken. Then plastic syringes without a tip were carefully inserted into each hole, and 10 ml of wet sediment was taken out. The sub-samples were then pressed out of the syringes into plastic bags that had been weighed in advance and stored in a refrigerator until they were measured in the laboratory. Upon arrival at the laboratory, the plastic bags with samples were weighed, the weight of the plastic bags was deducted, and the weight of 10 ml of the wet sample was noted. The weight of the dry sample was found by transferring the sample material onto a pre-weighted ceramic bowl before it was weighed again, then drying the bowl with sample in drying cabinet at 70 degrees C for 24 hours, and finally weighing the bowl with sample after drying. The weight of 10 ml of dry sample corresponds to the difference before and after drying. On the cruises 5-16 June 1994 (stations 76-133), 17-24 July 1995 (stations 135-180) and 9-19 September 1996 (stations 181-286), cores were taken with a multicorer. Plastic liners (length 61 cm, outer diameter 63 mm, inner diameter 59 mm) were placed in the corer, which after sampling was closed at both ends with rubber caps to prevent water in the core and on top of the core from leaking out or to evaporate. The cores were then transported to the laboratory in an upright position and stored as such until they were opened. After removing the rubber cap on top of the core, the water was drained by drilling holes in the plastic liner just above the top of the sediment. Lying in a rack, the core was then divided lengthwise with a circular saw by sawing through the plastic liner on both sides of the core. A thin string was then pulled in the saw gap through the sediment and the core split in two halves. Metal rings of known weight and volume were used to take sub-samples. The ring (approx. 2 cm in diameter) was gently pressed into the sediment at certain depths in the middle of one of the core halves, until the ring was full, and then gently tilted out with a spatula. The ends were levelled with a wire saw or spatula, and the excess sediment was discarded. The wet sample plus ring was weighed immediately after the sediment on the outside of the metal ring was removed. The sample was then pressed out into a pre-weighed porcelain bowl. Then the weight of bowl plus wet sample was measured, and the weight of wet sample was determined. The sample was dried in a porcelain bowl in a heating cabinet at 105 degrees C for 24 hours, before the sample plus bowl was weighed again and the dry weight was determined. More details on the methods can be found in Rise and Bøe (1995) and Bøe and Rise (1997).