Seasonal and diel patterns in sedimentary flux of krill fecal pellets recorded by an echo sounder

Handle URI:
http://hdl.handle.net/10754/554358
Title:
Seasonal and diel patterns in sedimentary flux of krill fecal pellets recorded by an echo sounder
Authors:
Røstad, Anders ( 0000-0002-2512-9033 ) ; Kaartvedt, Stein ( 0000-0002-8793-2948 )
Abstract:
We used a moored upward-facing 200 kHz echo sounder to address sedimentation of fecal pellets (FPs) from dielly migrating Meganyctiphanes norvegica. The echo sounder was located on the bottom at 150 m depth in the Oslofjord, Norway, and was cabled to shore for continuous measurements during winter and spring. Records of sinking pellets were for the first time observed with an echo sounder. Seasonal patterns of sedimentation of krill FPs were strongly correlated with data from continuous measurement of fluorescence, which illustrate the development of the spring bloom. Sedimenting particles were first observed as fluorescence values started to increase at the end of February and continued to increase until the bloom suddenly culminated at the end of March. This collapse of the bloom was detected on the echo sounder as a pulse of slowly sinking acoustic targets over a 2 d period. Prior to this event, there was a strong diel pattern in sedimentation, which correlated, with some time lag, with the diel migration of krill foraging at night near the surface. Pellet average sinking speeds ranged between 423 m d−1 and 804 m d−1, with a strong relation to pellet target strength, which is an acoustic proxy for size. This novel approach shows that echo sounders may be a valuable tool in studies of vertical pellet flux and, thereby, carbon flux, providing temporal resolution and direct observation of the sedimentation process, which are not obtained from standard methods.
KAUST Department:
Red Sea Research Center (RSRC)
Citation:
Seasonal and diel patterns in sedimentary flux of krill fecal pellets recorded by an echo sounder 2013, 58 (6):1985 Limnology and Oceanography
Journal:
Limnology and Oceanography
Issue Date:
Nov-2013
DOI:
10.4319/lo.2013.58.6.1985
Type:
Article
ISSN:
00243590
Additional Links:
http://doi.wiley.com/10.4319/lo.2013.58.6.1985
Appears in Collections:
Articles; Red Sea Research Center (RSRC); Red Sea Research Center (RSRC)

Full metadata record

DC FieldValue Language
dc.contributor.authorRøstad, Andersen
dc.contributor.authorKaartvedt, Steinen
dc.date.accessioned2015-05-21T06:34:52Zen
dc.date.available2015-05-21T06:34:52Zen
dc.date.issued2013-11en
dc.identifier.citationSeasonal and diel patterns in sedimentary flux of krill fecal pellets recorded by an echo sounder 2013, 58 (6):1985 Limnology and Oceanographyen
dc.identifier.issn00243590en
dc.identifier.doi10.4319/lo.2013.58.6.1985en
dc.identifier.urihttp://hdl.handle.net/10754/554358en
dc.description.abstractWe used a moored upward-facing 200 kHz echo sounder to address sedimentation of fecal pellets (FPs) from dielly migrating Meganyctiphanes norvegica. The echo sounder was located on the bottom at 150 m depth in the Oslofjord, Norway, and was cabled to shore for continuous measurements during winter and spring. Records of sinking pellets were for the first time observed with an echo sounder. Seasonal patterns of sedimentation of krill FPs were strongly correlated with data from continuous measurement of fluorescence, which illustrate the development of the spring bloom. Sedimenting particles were first observed as fluorescence values started to increase at the end of February and continued to increase until the bloom suddenly culminated at the end of March. This collapse of the bloom was detected on the echo sounder as a pulse of slowly sinking acoustic targets over a 2 d period. Prior to this event, there was a strong diel pattern in sedimentation, which correlated, with some time lag, with the diel migration of krill foraging at night near the surface. Pellet average sinking speeds ranged between 423 m d−1 and 804 m d−1, with a strong relation to pellet target strength, which is an acoustic proxy for size. This novel approach shows that echo sounders may be a valuable tool in studies of vertical pellet flux and, thereby, carbon flux, providing temporal resolution and direct observation of the sedimentation process, which are not obtained from standard methods.en
dc.relation.urlhttp://doi.wiley.com/10.4319/lo.2013.58.6.1985en
dc.rightsArchived with thanks to Limnology and Oceanographyen
dc.titleSeasonal and diel patterns in sedimentary flux of krill fecal pellets recorded by an echo sounderen
dc.typeArticleen
dc.contributor.departmentRed Sea Research Center (RSRC)en
dc.identifier.journalLimnology and Oceanographyen
dc.eprint.versionPublisher's Version/PDFen
dc.contributor.institutionDepartment of Biosciences, University of Oslo, Oslo, Norwayen
kaust.authorRøstad, Andersen
kaust.authorKaartvedt, Steinen
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