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

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2.3 Survey track and waypoints Theplannedwaypointswere providedby RENASandare givenin Table1. Table1. Designatedwaypointsfor the presentsurvey.Positionsfrom RENAS. Easting Northing Easting Northing WP001 412400 8000800 WP034 412000 8001600 WP002 412400 8001600 WP035 411975 8001600 WP003 412375 8001600 WP036 411975 8000800 WP004 412375 8000800 WP037 411950 8000800 WP005 412350 8000800 WP038 411950 8001600 WP006 412350 8001600 WP039 411925 8001600 WP007 412325 8001600 WP040 411925 8000800 WP008 412325 8000800 WP041 411900 8000800 WP009 412300 8000800 WP042 411900 8001600 WP010 412300 8001600 WP043 411875 8001600 WP011 412275 8001600 WP044 411875 8000800 WP012 412275 8000800 WP045 411850 8000800 WP013 412250 8000800 WP046 411850 8001600 WP014 412250 8001600 WP047 411825 8001600 WP015 412225 8001600 WP048 411825 8000800 WP016 412225 8000800 WP049 411800 8000800 WP017 412200 8000800 WP050 411800 8001600 WP018 412200 8001600 WP051 411775 8001600 WP019 412175 8001600 WP052 411775 8000800 WP020 412175 8000800 WP053 411750 8000800 WP021 412150 8000800 WP054 411750 8001600 WP022 412150 8001600 WP055 411725 8001600 WP023 412125 8001600 WP056 411725 8000800 WP024 412125 8000800 WP057 411700 8000800 WP025 412100 8000800 WP058 411700 8001600 WP026 412100 8001600 WP059 411675 8001600 WP027 412075 8001600 WP060 411675 8000800 WP028 412075 8000800 WP061 411650 8000800 WP029 412050 8000800 WP062 411650 8001600 WP030 412050 8001600 WP063 411625 8001600 WP031 412025 8001600 WP064 411625 8000800 WP032 412025 8000800 WP065 411600 8000800 WP033 412000 8000800 WP066 411600 8001600 Theplannedsurveytrackisshownin Figure6. Akvaplan-niva AS, 9296 Tromsø 10 www.akvaplan.niva.no
Figure6. Plannedsurveyroutefor detailedsite surveyat Darwin,August2012. Thesurveygrid comprised33 lines,eachof which is 800m in length.Thedistancebetweenthe lines is 25 m. The total length of the survey route (using a hypothetical straight line between the waypointsand includingthe transit between lines) was approximately 27 200 m (26 400 m if only linesare included). All the abovewaypointswere used,althoughthe actualROVtrack variedslightly accordingto currentsand objects of biologicalinterest. Because currentswere reported to havea strongeasterlydirection,the directionof the maintracklineswasrotated 90 degrees. The ROVwas launchedon 18.08.2012at 13:53 local time (-2h for UTC),starting from the first waypoint at 14:41. The survey was completed on 19:08.2012 at 06:24 and ROVrecovery was completed at 06:47. Total video time was 17h 05m 06s, and total ROVdeploymenttime was the same(videopermanentlyon). 2.4 Observation logs and event logging 2.4.1 Steps taken to address challenges Oneof the challengesof conducting biologicalanalysesfrom non-geo-referencedvideo and/or still photographsis the time-consumingwork of matching imagesor recorded 'events' to geographic positions.TheROVdive log recordsthe time of eachnote, or event taken,but the positionsneedto be matchedwith the surveyorlog.Thesurveyorlog continuouslyrecordsthe ROVtrack,but doesnot containthe biologicalobservations. Detailed site survey at PL531 Darwin Akvaplan-niva AS Rapport 6051 - 1 11
Page 1 and 2: Detailed visual seabed survey at dr
Page 3: Akvaplan -niva AS Rådgivning og fo
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 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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