Corals and petroleum activity

Transkript

1 Corals and petroleum activity Pål Buhl-Mortensen Photo: Rudolf Svensen

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5 Valuable habitats - Support a great biodiversity - Essential for sensitive and /or rare species - Important for sustaining sound ecological processes Sensitive habitats - Little resistance against external stress? - Low regeneration capability?

6 Many types of sensitive habitats

7 Lophelia pertusa a reefbuilding stone coral Polyps Beskrevet av Linné (1758) Lengdevekst snitt:~ 7 mm/år, Maks 3 cm/år Kolonier opp til ca 2 m i høyde Rev opp til 35 m høye og ca 1 km lange Colony Eldste rev i Norge rundt 9000 år gamle Spiser hovedsakelig zooplankton, men også phytodetritus Gyter i februar/mars

8 Important questions Which environemtal factors controle the distribution of cold water corals? Are cold water corals important for other species, and what are their function in the ecosystem? How sensitive are cold water corals?

9 Offshore petroleumsaktiviteter - New technology - ROV - Multibeam - Sidescan sonar new knowledge Statoils oppdagelser langs Haltenpipe i Oppstart av EU prosjektene ACES, HERMES Flere havbunnsobservatorier planlegges

10 Tautrarevet på Selliggrunnen i Trondheimsfjorden Verdens grunneste dypvannskorallrev verneområde Yndet dykkeklubb blant spesielt interesserte dykkere

11 Distribution of Lophelia pertusa in Norway Rapportert av fiskere Verifisert forekomst Rev-område Sannsynligvis > 6000 rev utenfor Norskekysten Opp til ca 45 km i lengde utenfor Røst Del av Sularevet - revkompleks ~500 enkeltrev - kartlagt med flerstråleekkolodd - undersøkt med ROV og ubåt

12 MAREANO seabed mapping areas Barents Sea Tromsøflaket 2010 Norwegian Sea This area contains some of the largest deep-water coral reefs known, e.g. the Røst reef and the Træna reef area, as well as the northernmost known living Lophelia-reef in the world ( Korallen ).

13 Korallrev utenfor Vesterålen 330 levende Lophelia rev i Hola Gassoppkommer M karbonatskorper og bakteriematter Korallrev er enkle å kartlegge i forhold til mange andre naturtyper - De er synlige på multibeam

14 Biodiversity Great habitat variation over short distances Patchy habitats Challenging to monitor

15 Goals To increase the scientific basis for future decisions relating to petroleum activities vs. Protection of corals To investigate how close a drilling site in the Trænahola area (drilled in ) can be detected in the skeletons of Lophelia pertusa Find out if this activity has inflenced the corals negatively

16 Trænahola

17 Reef orientation fits with current directions 1 2 3

18 Elongated reefs in the Trænahola and Hola Havforskingsinstituttets koralldatabase

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20 Skeleton analyses Septum Theca Dissepiment - Growth layers - Organic layers - Trace elements - Stabile isotopes

21 VG36-1-3

22 Conclusions It is possible to identify areas in the skeleton representing the year of drilling. Barite crystals were identified among sediment particles trapped in skeleton cavities in dead coral polyps older than 6 years. The highest consentration was found in skeletons older than 13 years. Occurrence of barite in skeleton cavities was related to an increased mortality of coral polyps. It is therefore likely that reefs within a distance of 500 m downcurrent from the drilling site will be negatively affected if sediments and drillingmud is released.

23 Nord (UTM) Nord (UTM) Nord (UTM) KP ROV 1 ROV 2 Rørledning Levende Lophelia Død Lophelia KA1 ROV 1 ROV 2 ROV 3 Fylling Rørledning Levende Lophelia Øst (UTM) Død Lophelia Lopheliagrus KA ROV 1 ROV 2 ROV 3 ROV 4 Ankerkjetting Rørledning Levende Lophelia Død lophelia Lopheliagrus Øst (UTM) Øst (UTM)

24 Antall korallrev i områdene rundt brønnramme A og B (sentralt i kartene), tolket fra flerstrålekart og sidescan sonar-bilder. Hver av rutene måler 200x200m.:

25 Oversikt over avbøtende for påvirkning fra potensielt negative faktorer: Faktor Tiltak Kommentar Avstand til Problematisk ved høye - Størst mulig avstand korallhabitat tettheter i et større område Utslipp av borekaks Oppvirvling av sedimenter Fysisk påvirkning (knusing) - Flytte utslippspunkt for borekaks - Periodevis utslipp Lite aktuelt? - Unngå nedspyling av rør - Unngå dumping av steinmasser i områder med høy koralltetthet - Deponering av steinmasser fra lav høyde over bunn - Unngå bevegelse i ankerkabler til platform - Unngå bruk av ankere ved legging av rør - Bruk av dynamisk posisjonert leggefartøy Sees i forhold til fremherskende strømretning

26 The negative effect of particle exposure may depend both on particle consentration and exposure time. During long time exposure for relatively low but elevated consentrations the corals will probably use more energy keeping the surface clean than they manage to digest with a normal ingestion rate Monitoring the effects is needed.

27 Landere på Morvin Strøm, salt & temp Partikkelkonsentrasjon Adferd (visuell overvåking)

28 Kabeltilknyttet observatorium Instruments Physical sensors CTD Current meter Chemical and optical sensors Trasmissometer Light scattering Fluorometer Variable/function Temperature and salinity Local velocity and direction Turbidity Particles Pigments SAMI-CO 2 sensor Alkalinity, ph and CO 2 Aanderaa TS and optode Oxygen, temperature and salinity Acoustic systems Digital cameras EK 60 splitbeam echo sounder ADCP - Acoustic Doppler Current Profiler of high frequency Density measurements and target t racking of fish and large plankton Vertical current profile from surface to bottom Light sensitive overview camera (SIT Abundance and behaviour of fish, replacement) Relative abundance of zooplankton Close-up camera Information technology PC (250 GB HD, 1 GB RAM), video-card with built-in file compression Ethernet converter, tele communication (wireless LAN) Behaviour and interactions of coral polyps and common associated species Temporal storage of large amounts of data Communication of data The Proposed Brattholmen Cabled Seabed Observatory

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30 The discharge risk values are low for all impact factors except the discharge of drill cuttings if these are discharged to the sea (base case). The latter is a result of the presence of cold water corals. The risk level for the nearest coral sites may be characterised as considerable. Risk reducing measures is recommended, either by bringing the cuttings to shore or by controlled deposition at the seabed away from the corals. Effect monitoring at the coral sites is recommended if the cuttings are discharged. Risk reduction measures are described in the application for permit from Sft.

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