Abstract
An environmental monitoring survey was carried out at Ormen Lange in Region V on behalf of Norske Shell. The samples were collected at 19 stations by use of a 0.25 m{sub 2} box corer and carried out in connection with the field work in Region VI. The station depths varied between 823 and 925 m. The sediments at Ormen Lange are classified as silt with a high amount of pelite (> 90 %) and TOM (> 9 %). The amount of pelite is higher than that found in the baseline survey in 2004 at all stations. Whether this is a result of changes in sediment composition or a difference in analytical methods used is not known. With the exception of station OL-01 and OL-09, where a small increase has occurred, the amount of TOM has decreased at the stations since 2004. The concentrations of hydrocarbons and metals in the sediments at Template D, can be regarded as the natural background level for these parameters. The average amount of THC in the sediments around Template D is 11.7 +- 1.8 mg/kg in this base line survey. The average level of THC at template A and B was at the same level
More>>
Citation Formats
Mannvik, Hans-Petter, Wasbotten, Ingar Halvorsen, and Cochrane, Sabine.
Environmental Survey at Ormen Lange, June 2009.
Norway: N. p.,
2010.
Web.
Mannvik, Hans-Petter, Wasbotten, Ingar Halvorsen, & Cochrane, Sabine.
Environmental Survey at Ormen Lange, June 2009.
Norway.
Mannvik, Hans-Petter, Wasbotten, Ingar Halvorsen, and Cochrane, Sabine.
2010.
"Environmental Survey at Ormen Lange, June 2009."
Norway.
@misc{etde_1005109,
title = {Environmental Survey at Ormen Lange, June 2009}
author = {Mannvik, Hans-Petter, Wasbotten, Ingar Halvorsen, and Cochrane, Sabine}
abstractNote = {An environmental monitoring survey was carried out at Ormen Lange in Region V on behalf of Norske Shell. The samples were collected at 19 stations by use of a 0.25 m{sub 2} box corer and carried out in connection with the field work in Region VI. The station depths varied between 823 and 925 m. The sediments at Ormen Lange are classified as silt with a high amount of pelite (> 90 %) and TOM (> 9 %). The amount of pelite is higher than that found in the baseline survey in 2004 at all stations. Whether this is a result of changes in sediment composition or a difference in analytical methods used is not known. With the exception of station OL-01 and OL-09, where a small increase has occurred, the amount of TOM has decreased at the stations since 2004. The concentrations of hydrocarbons and metals in the sediments at Template D, can be regarded as the natural background level for these parameters. The average amount of THC in the sediments around Template D is 11.7 +- 1.8 mg/kg in this base line survey. The average level of THC at template A and B was at the same level in the base line survey in 2004, 9.7 +- 0.6 mg/kg. In the present survey the average amount of THC in the sediments at Template A and B has increased to 17.0 +- 3.9 mg/kg. 11 of 14 stations at Template A and B have slightly elevated levels of barium and zinc in the sediments and sediments at three stations are elevated with mercury. In the present survey the mollusks dominates the fauna at Ormen Lange. The number of individuals at the stations (0.4 m{sub 2}) is high (1553 - 2833), while the number of taxa is relatively low (51 - 73), resulting in a very low diversity (H' 2.4 - 3.3). This is due to the over dominance by two mussels (Thyasira minuta and T. equalis) at all stations. However, the dominant species registered are known to be abundant in sediment with high amount of pelite and organic material. Due to the different sampling strategy and area, a direct comparison with the baseline survey is not possible. In 2004 the number of individuals and taxa per station (0.25 m{sub 2}) varied from 732 to 1613 and 47 to 78, respectively, while the diversity H' varied between 4.2 and 5.1. In that survey the registered Thyasira species were less abundant. The multivariate analyses show a high degree of similarity in the faunal composition between the stations indicating that the fauna is evenly distributed over the area. In the correspondence analyses the distribution of the fauna was significant correlated with the station depth and the amount of THC and Ba in the sediment. However, the amount of both THC (< 20 mg/kg dried sediment) and Ba (< 353.5 mg/kg) are relatively low at Ormen Lange, and the results from the analyses indicate that the faunal distribution is a result of natural variation of the physical conditions in the area. On this basis it is concluded that the fauna at Ormen Lange is undisturbed by the petroleum activity in the area. (Author)}
place = {Norway}
year = {2010}
month = {Jul}
}
title = {Environmental Survey at Ormen Lange, June 2009}
author = {Mannvik, Hans-Petter, Wasbotten, Ingar Halvorsen, and Cochrane, Sabine}
abstractNote = {An environmental monitoring survey was carried out at Ormen Lange in Region V on behalf of Norske Shell. The samples were collected at 19 stations by use of a 0.25 m{sub 2} box corer and carried out in connection with the field work in Region VI. The station depths varied between 823 and 925 m. The sediments at Ormen Lange are classified as silt with a high amount of pelite (> 90 %) and TOM (> 9 %). The amount of pelite is higher than that found in the baseline survey in 2004 at all stations. Whether this is a result of changes in sediment composition or a difference in analytical methods used is not known. With the exception of station OL-01 and OL-09, where a small increase has occurred, the amount of TOM has decreased at the stations since 2004. The concentrations of hydrocarbons and metals in the sediments at Template D, can be regarded as the natural background level for these parameters. The average amount of THC in the sediments around Template D is 11.7 +- 1.8 mg/kg in this base line survey. The average level of THC at template A and B was at the same level in the base line survey in 2004, 9.7 +- 0.6 mg/kg. In the present survey the average amount of THC in the sediments at Template A and B has increased to 17.0 +- 3.9 mg/kg. 11 of 14 stations at Template A and B have slightly elevated levels of barium and zinc in the sediments and sediments at three stations are elevated with mercury. In the present survey the mollusks dominates the fauna at Ormen Lange. The number of individuals at the stations (0.4 m{sub 2}) is high (1553 - 2833), while the number of taxa is relatively low (51 - 73), resulting in a very low diversity (H' 2.4 - 3.3). This is due to the over dominance by two mussels (Thyasira minuta and T. equalis) at all stations. However, the dominant species registered are known to be abundant in sediment with high amount of pelite and organic material. Due to the different sampling strategy and area, a direct comparison with the baseline survey is not possible. In 2004 the number of individuals and taxa per station (0.25 m{sub 2}) varied from 732 to 1613 and 47 to 78, respectively, while the diversity H' varied between 4.2 and 5.1. In that survey the registered Thyasira species were less abundant. The multivariate analyses show a high degree of similarity in the faunal composition between the stations indicating that the fauna is evenly distributed over the area. In the correspondence analyses the distribution of the fauna was significant correlated with the station depth and the amount of THC and Ba in the sediment. However, the amount of both THC (< 20 mg/kg dried sediment) and Ba (< 353.5 mg/kg) are relatively low at Ormen Lange, and the results from the analyses indicate that the faunal distribution is a result of natural variation of the physical conditions in the area. On this basis it is concluded that the fauna at Ormen Lange is undisturbed by the petroleum activity in the area. (Author)}
place = {Norway}
year = {2010}
month = {Jul}
}