Potential implications on the pelagic fish and zooplankton community of artificially induced deep-water releases of oil and gas during DeepSpill_2000 – an innovative acoustic approach.
During the DeepSpill_2000 field experiment (Johansen et al., 2001) oil and gas were artificially released on several occasions from a water depth of 844 meters at the Helland-Hansen site in the Norwegian sea. Prior to and during these releases a variety of sampling gear, echo sounders and other inst...
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ftimr:oai:imr.brage.unit.no:11250/113901 2023-05-15T17:47:09+02:00 Potential implications on the pelagic fish and zooplankton community of artificially induced deep-water releases of oil and gas during DeepSpill_2000 – an innovative acoustic approach. Knutsen, Tor Serigstad, Bjørn 2001-12-15 application/pdf http://hdl.handle.net/11250/113901 eng eng Havforskningsinstituttet Fisken og havet;14-2001 urn:issn:0071-5638 http://hdl.handle.net/11250/113901 43 s. oil spill oljeutslipp acoustics akustikk VDP::Mathematics and natural science: 400::Zoology and botany: 480::Ecotoxicology: 489 VDP::Mathematics and natural science: 400::Zoology and botany: 480::Marine biology: 497 Research report 2001 ftimr 2021-09-23T20:16:17Z During the DeepSpill_2000 field experiment (Johansen et al., 2001) oil and gas were artificially released on several occasions from a water depth of 844 meters at the Helland-Hansen site in the Norwegian sea. Prior to and during these releases a variety of sampling gear, echo sounders and other instrumentation were used to monitor and obtain information on the environmental conditions, oil and gas plumes and the biological activity in the experimental region. The main objective of the present work has been to provide a general description of the biological community of the experimental region, and to provide information on the variability of biological scatterers throughout the water column. By exploring and evaluating the short-term variability of the biological scattering structures, the organisms therein and concurrently examine scattering from the released oil and gas, new insights on how rising oil and gas might interact with the deep-water plankton and fish community of the experimental region could be gained. Acoustic scattering from oil and gas was easily observed during all experimental spill events and some situations are presented in this report. The magnitude of the acoustic scattering from organisms inhabiting the Deep Scattering Layer (DSL) between 300-500 m depth for an undisturbed situation and its natural variability is documented. It is shown that rising oil-gas plumes certainly influences the otherwise quite homogeneous DSL structure, although the precise mechanisms involved are still not revealed. When all scattering, from structures that with certainty can be attributed to the released oil and gas were excluded, the remaining acoustic scattering from the DSL seem to be nearly an order of magnitude higher compared to an undisturbed situation. The reason for this is still uncertain, but some tentative hypotheses are formulated. The most plausible explanation seem to be that a fraction of the released compounds and in particular gas bubbles, for various reasons have a prolonged residence time within the region of the DSL, hence contributing significantly to the increased scattering observed during the spills. Report Norwegian Sea Institute for Marine Research: Brage IMR Norwegian Sea Johansen ENVELOPE(67.217,67.217,-70.544,-70.544) Helland ENVELOPE(6.470,6.470,62.608,62.608) |
institution |
Open Polar |
collection |
Institute for Marine Research: Brage IMR |
op_collection_id |
ftimr |
language |
English |
topic |
oil spill oljeutslipp acoustics akustikk VDP::Mathematics and natural science: 400::Zoology and botany: 480::Ecotoxicology: 489 VDP::Mathematics and natural science: 400::Zoology and botany: 480::Marine biology: 497 |
spellingShingle |
oil spill oljeutslipp acoustics akustikk VDP::Mathematics and natural science: 400::Zoology and botany: 480::Ecotoxicology: 489 VDP::Mathematics and natural science: 400::Zoology and botany: 480::Marine biology: 497 Knutsen, Tor Serigstad, Bjørn Potential implications on the pelagic fish and zooplankton community of artificially induced deep-water releases of oil and gas during DeepSpill_2000 – an innovative acoustic approach. |
topic_facet |
oil spill oljeutslipp acoustics akustikk VDP::Mathematics and natural science: 400::Zoology and botany: 480::Ecotoxicology: 489 VDP::Mathematics and natural science: 400::Zoology and botany: 480::Marine biology: 497 |
description |
During the DeepSpill_2000 field experiment (Johansen et al., 2001) oil and gas were artificially released on several occasions from a water depth of 844 meters at the Helland-Hansen site in the Norwegian sea. Prior to and during these releases a variety of sampling gear, echo sounders and other instrumentation were used to monitor and obtain information on the environmental conditions, oil and gas plumes and the biological activity in the experimental region. The main objective of the present work has been to provide a general description of the biological community of the experimental region, and to provide information on the variability of biological scatterers throughout the water column. By exploring and evaluating the short-term variability of the biological scattering structures, the organisms therein and concurrently examine scattering from the released oil and gas, new insights on how rising oil and gas might interact with the deep-water plankton and fish community of the experimental region could be gained. Acoustic scattering from oil and gas was easily observed during all experimental spill events and some situations are presented in this report. The magnitude of the acoustic scattering from organisms inhabiting the Deep Scattering Layer (DSL) between 300-500 m depth for an undisturbed situation and its natural variability is documented. It is shown that rising oil-gas plumes certainly influences the otherwise quite homogeneous DSL structure, although the precise mechanisms involved are still not revealed. When all scattering, from structures that with certainty can be attributed to the released oil and gas were excluded, the remaining acoustic scattering from the DSL seem to be nearly an order of magnitude higher compared to an undisturbed situation. The reason for this is still uncertain, but some tentative hypotheses are formulated. The most plausible explanation seem to be that a fraction of the released compounds and in particular gas bubbles, for various reasons have a prolonged residence time within the region of the DSL, hence contributing significantly to the increased scattering observed during the spills. |
format |
Report |
author |
Knutsen, Tor Serigstad, Bjørn |
author_facet |
Knutsen, Tor Serigstad, Bjørn |
author_sort |
Knutsen, Tor |
title |
Potential implications on the pelagic fish and zooplankton community of artificially induced deep-water releases of oil and gas during DeepSpill_2000 – an innovative acoustic approach. |
title_short |
Potential implications on the pelagic fish and zooplankton community of artificially induced deep-water releases of oil and gas during DeepSpill_2000 – an innovative acoustic approach. |
title_full |
Potential implications on the pelagic fish and zooplankton community of artificially induced deep-water releases of oil and gas during DeepSpill_2000 – an innovative acoustic approach. |
title_fullStr |
Potential implications on the pelagic fish and zooplankton community of artificially induced deep-water releases of oil and gas during DeepSpill_2000 – an innovative acoustic approach. |
title_full_unstemmed |
Potential implications on the pelagic fish and zooplankton community of artificially induced deep-water releases of oil and gas during DeepSpill_2000 – an innovative acoustic approach. |
title_sort |
potential implications on the pelagic fish and zooplankton community of artificially induced deep-water releases of oil and gas during deepspill_2000 – an innovative acoustic approach. |
publisher |
Havforskningsinstituttet |
publishDate |
2001 |
url |
http://hdl.handle.net/11250/113901 |
long_lat |
ENVELOPE(67.217,67.217,-70.544,-70.544) ENVELOPE(6.470,6.470,62.608,62.608) |
geographic |
Norwegian Sea Johansen Helland |
geographic_facet |
Norwegian Sea Johansen Helland |
genre |
Norwegian Sea |
genre_facet |
Norwegian Sea |
op_source |
43 s. |
op_relation |
Fisken og havet;14-2001 urn:issn:0071-5638 http://hdl.handle.net/11250/113901 |
_version_ |
1766151487729172480 |