Detailed visual seabed survey at drilling site 7218/11-1

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Cover picture: sponges at the sediment surface at Darwin, PL531, August, 2012. White: Geodia and yellow: Apl ysilla . Photo: Oceaneering AS/ Akvaplan -niva.
Akvaplan -niva AS Rådgivning og forskning innen miljø og akvakultur Org.nr: NO 937 375 158 MVA Framsenteret 9296 Tromsø Tlf: 77 75 03 00, Fax: 77 75 03 01 www.akvaplan.niva.no Report title Detailedvisualseabedsurveyat drilling site 7218/11-1, Darwin PL 531 in the BarentsSea- with specialfocuson spongeassemblages . Author(s) SabineCochrane RunePalerud JesperHansen AnnaHelenaFalk Client RepsolExplorationNorwayAS(RENAS) Akvaplan -niva report no. 6051– 1 Date 25.09.2012 No. of pages 64 Distribution Restricted Client’s reference SigurdHellem Summary On commissionto RENASNorway, Akvaplan-niva provided biological assistanceduring ROVsediment mappingaround the planneddrillingsite at the Darwinprospect(PL531)in the BarentsSea, August2012. ROVfilming along a transect length of approximately27 200 m was carried out, over approximately17 hours.Thisreport documentsthe distributionanddensitiesof the spongepopulationsin the area,together with other biologicalandsedimentcharacteristics.In general,the seafloorcloseto the planneddrilling site at the Darwinprospectcanbe characterizedasmainlycomprisedof mud, with somescatteredstones. The area is visibly rich in bottom currents, and the visible sea-floor communitiesare dominated by sponges suchasGeodia,Aplysilla,Farreaoccaandassociatedorganismssuchassquatlobsters(Munida). Themain challengesfor spongeassessmentsare outlined, and the approachappliedduring the surveyis describedin detail. Further,a summaryof stateof knowledgeregardingspongesandmethodsof assessing spongeassemblagesisoutlined. Project manager Quality control ler SabineCochrane LarsHenrikLarsen © 2012 Akvaplan -niva AS. This report may only be copied as a whole. Copying of part of this report (sections of text, illustrations, tables, conclusions, etc.) and/or reproduction in other ways, is only permitted with written consent from Akvaplan -niva AS.
Page 1: Detailed visual seabed survey at dr
Page 6 and 7: List of figures and tables FIGURE1.
Page 8 and 9: Preface In August,2012,Akvaplan-niv
Page 10 and 11: Figure2. ROVtransectsandrecordsof s
Page 12 and 13: 2 Materials and methods 2.1 Vessel
Page 14 and 15: 2.3 Survey track and waypoints Thep
Page 16 and 17: Akvaplan-niva haspreviouslyworked w
Page 18 and 19: Figure7. Over4 tonnesof sponges(pre
Page 20 and 21: Figure10. BarentsSea.Spongebycatchi
Page 22 and 23: Somespongesform densereefs,and prov
Page 24 and 25: Figure14. Photosfrom Mercier(2012)s
Page 26 and 27: Figure16. Imagefrom Salina,2010,cla
Page 28 and 29: It is clear that Cochraneadopted a
Page 30 and 31: 5.2 Seafloor conditions 5.2.1 Sedim
Page 32 and 33: 5.3.2 Plots of sponge distribution
Page 34 and 35: Figure24. Locationof the 30 imagess
Page 36 and 37: Position16. 0-1 % coverage Position
Page 38 and 39: Position15. 1-5 % coverage.Geodiaan
Page 40 and 41: 5.3.3 Overall assessment of sponge
Page 42 and 43: 5.3.5 Dominant sponge species recor
Page 44 and 45: Hymedesmia Hymedesmia Polymastia Po
Page 46 and 47: Figure34. Observationsof the yellow
Page 48 and 49: Figure36. Observationsfor the blues
Page 50 and 51: Figure38. Upper:spottedwolffishrest
Page 52 and 53:
Figure40. Largestonein foreground,w
Page 54 and 55:
Table 6. Summaryof environmentalcos
Page 56 and 57:
5.4.2.2 Deposition Case 2: to seafl
Page 58 and 59:
5.4.2.4 Deposition Case 7: Depositi
Page 60 and 61:
5.4.3 Comparative assessment Table7
Page 62 and 63:
6 References Auster, P.J. 2007. Lin
Page 64:
Appendices Anelectronicsupplement(o
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Detailed visual seabed survey at drilling site 7218/11-1

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