Sampling Protocols

‘Standard’ sampling protocol

As far as possible standard sampling protocols followed (or were consistent with) those of earlier ‘Atlantic Margin Environmental Survey’ cruises (AFEN ’9620, AFEN ’9821, DTI ’9922). Of necessity, variant protocols were followed for samples from the Megacorer, box corer and Day grab.

Megacorer

On recovery of the corer, the function of each coring unit was checked and recorded. Core lengths were measured and recorded and any surface and profile features noted. Sample acceptance was based on the following criteria: cores >10cm in length; core surfaces essentially level; and, the sediment-water interface intact. The latter criterion was partly relaxed where localised disturbance had been caused by the dislodgement of gravel during core penetration. Acceptable cores were removed from the corer and transferred to the ship’s laboratories for subsequent processing. In all cases, processing began with the careful removal of the supernatant water using gentle overflow, pump siphon and / or syringe as appropriate to the sediment type.

For macrobenthos samples, cores were further processed as follows. Cores were extruded (by plunger from below) and the 0-10cm horizon sectioned off. Corresponding horizons from successive cores were pooled to produce a nominal sample size of eight cores. Macrobenthos samples were then elutriated through a 500µm mesh sieve. The resultant residue was fixed and preserved in 10% borax buffered formalin.

Hydrocarbon samples were processed by extruding the cores into a pre-cleaned metal collar and sectioning off the 0-2 cm horizon. The samples were preserved, in pre-cleaned glass pots, by freezing at -20ºC.

Heavy metal samples were processed by extruding the cores into a pre-cleaned polycarbonate collar and sectioning off the 0-2cm horizon. The samples were preserved, in pre-cleaned polycarbonate pots, by freezing at -20ºC.

Particle size samples were processed by extruding the cores into a polycarbonate collar and sectioning off the 0-5cm horizon. The samples were preserved, in polythene bags, by freezing at -20ºC. This material was also used to provide a total organic carbon and nitrogen sample.

Box corer

On recovery of the corer, its function was checked and recorded. If, on inspection through the top vents, the core appeared to be acceptable, the box and spade were dismounted and moved to a clear deck space. Sample acceptance was based on the following criteria: cores >10cm in length; core surfaces essentially level (excepting relief deemed to be natural); sediment surface covering the full cross-sectional area of the box (excepting limited, 5cm or less, lateral

20 _{Bett, B.J. et al., 1997 RRS Charles Darwin Cruise 101C Leg 2, 14 Jul-20 Aug 1996. Atlantic Margin Environmental Survey: seabed} survey of the shelf edge and slope west of Shetland. Southampton, UK, Southampton Oceanography Centre, 127pp. (Southampton Oceanography Centre Cruise Report, 7)

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Bett, B.J. et al., 1999. RRS Charles Darwin Cruise 112C, 19 May-24 Jun 1998. Atlantic Margin Environmental Survey: seabed survey of deep-water areas (17th round Tranches) to the north and west of Scotland. Southampton, UK, Southampton Oceanography Centre, 171pp. (Southampton Oceanography Centre Cruise Report, 25).

compression); and, essentially clear supernatant water (limited resuspension, particularly following a recovery that crashed the box core off the ship’s hull was deemed acceptable). Processing of acceptable cores started with the division of the core’s surface into macrobenthos and chemistry areas. A metal insert of either 0.1m² or 0.15m² was pushed into the sediment with one of its edges against one side of the box. The open sediment area and that enclosed by the insert were then separately drained of supernatant water using a pump siphon. The overlying water from the 0.1m² area (whether enclosed or open) was drained through a 500µm sieve and any residue subsequently combined with the 0-10cm sediment layer (see below). The overlying water from the 0.15m² area (whether enclosed or open) was drained to waste. Once drained, the surface of the core was examined and a record made of any surface features and / or fauna of note.

For macrobenthos samples, cores were further processed as follows. The front of the box was removed and the sediment underlying the 0.1m² area trowelled out from the 0-10cm horizon. Macrobenthos samples were then elutriated through a 500µm sieve mesh. The resultant residue was fixed and preserved in 10 % borax buffered formalin.

Hydrocarbon samples were collected from the 0.15m² area using a pre-cleaned metal scoop to a nominal depth of 2cm. The samples were preserved, in pre-cleaned glass pots, by freezing at -20ºC.

Heavy metal samples were collected from the 0.15m² area using a pre-cleaned plastic scoop to a nominal depth of 2cm. The samples were preserved, in pre-cleaned polycarbonate pots, by freezing at -20ºC.

Particle size samples were collected from the 0.15m² area using a plastic scoop to a nominal depth of 5cm. The samples were preserved, in polythene bags, by freezing at -20ºC. This material was also used to provide a total organic carbon and nitrogen sample.

Day grab

On recovery of the grab, its function was checked and recorded. Sample acceptance was based on the following criteria: grab fully closed; grab holding or only slowly leaking supernatant water.

Macrobenthos samples were then processed by elutriating the complete contents of the grab though a 500µm sieve mesh. The resultant residue was fixed and preserved in 10% borax buffered formalin.

Hydrocarbon samples were collected from the grab using a pre-cleaned metal scoop to a nominal depth of 2cm. The samples were preserved, in pre-cleaned glass pots, by freezing at - 20ºC.

Heavy metal samples were collected from the grab using a pre-cleaned plastic scoop to a nominal depth of 2cm. The samples were preserved, in pre-cleaned polycarbonate pots, by freezing at -20ºC.

Particle size samples were collected from the grab using a plastic scoop to a nominal depth of 5cm. The samples were preserved, in polythene bags, by freezing at -20ºC. This material was also used to provide a total organic carbon and nitrogen sample.

Additions to the standard sampling protocol

Additional macrobenthos material

(a) At numerous sites (see sample catalogue, Section 8) a larger macrobenthos sample size was retained, i.e. more than the notional sample size of 8-cores from the Megacorer or 0.1m2 from the box corer, was achieved. Note also the replicate material available from some sites (see e.g. Enterprise survey, Section 8.7). Please consult the Station List (Section 9) for full details).

(b) Small macrobenthos passing through a 500µm mesh but retained on a 250µm mesh (otherwise treated as per standard 500µm samples). Small macrobenthos were routinely collected on the West of Shetland transect (Sites B5-Tr1000) to provide continuity with earlier transect surveys (AFEN ’96 and ’98). Small macrobenthos were also collected in the benthic body size study (see below).

(c) Qualitative macrobenthos. Given persistent difficulties in obtaining quantitative material from the West of Shetland contourite area, and the potentially novel nature of this habitat, qualitative samples were retained (0.25m2 samples from Sites CS2, 3, 4 and 7).

Benthic body size study

Intensive biological sampling to investigate variations in benthic body size distributions was carried out in the deep Faroe-Shetland Channel (Site FSC9) and in the Fladen Ground (sampling effort spread across Sites T1-117, T3-69, 73, 77 and T6-8). In both of these locations samples were collected for:

i) Larger (>500µm) macrobenthos; (methods as above) ii) Smaller (<500 >250µm) macrobenthos; (methods as above)

iii) Mesobenthos (i.e. of body sizes intermediate to macro- and meio-benthos); sampled with a single unsieved Megacore sample (80cm2) sectioned to the 0-10cm sediment horizon (sample preservation as for macrobenthos).

iv) Meiobenthos; sampled from a single Megacore sample using three 20mm internal diameter syringes (total area c. 10cm2) sectioned to the 0-5cm sediment horizon (sample preservation as for macrobenthos).

Full details of these methods, subsequent sample processing and the results of the study are given in Kaariainen & Bett (2006)23.

Meiobenthos

(a) Standard samples (methodology as per body size study above) were collected opportunistically in the Faroe Bank Channel, Enterprise survey area, North of Shetland and in Fladen Ground. They were also collected routinely (i.e. at all sites) on the Faroe-Shetland Channel and West of Shetland transects (see table below).

Survey Sites Samples

Faroe Bank Channel FSC1000, L, R2, S, WTS3, 4, 12, 13, 15 9

Faroe-Shetland Channel axial transect FSC1-10 14

West of Shetland transect Tr250, 300, 350, 450, 550, 600, 650, 800, 900, 1000, 1100,

1200, 1250, 1300, L4, 5, S2 31

Enterprise survey (Tranche 4) ET1, 2, 3, 6, 8, 10, 11, 13, 16 10

North of Shetland area (Tranches 65-67) NR4, NU1, 2, NW1, 2, 2, SBB1, SBC2, 5, SBE5 11 Fladen Ground (North Sea) ALABA4, T3-55, 59, 61, 63, 65, 69, 71, 80, T6-1, 3, 5, 6, 7, 8 15

(b) Qualitative material was also collected from some West of Shetland transect sites (Tr450, 600, 650 and L4) and Faroe-Shetland Channel Site FSC10 by resuspending the superficial sediments in ‘spare’ Megacores, decanting off this suspension and preserving it as per macrobenthos samples (see above).

(c) Live material: A number of cores ((Sites FSC10, NU2, S2) were retained for live study of the meiobenthos. About 10cm of the sediment column from ‘spare’ Megacores and a similar depth of supernatant was extruded in to a polycarbonate tube. The tube was then bunged from below and stored in a larger container filled with supernatant water from other cores and maintained at near-habitat temperature (typically 0°C).

Foraminifera

Samples intended for the study of foraminiferans were collected at Site FSC10 and at all sites from 300m and deeper on the West of Shetland transect (Tr300, 350, 450, 550, 600, 650, 800, 900, 1000, 1100, 1200, 1250, 1300, L4, 5, S2). Samples from single Megacores were sectioned in to 1cm sediment horizons (0-5 or 0-10cm) and preserved as per macrobenthos samples (see above).

Microbiology

Microbiology samples were collected opportunistically on behalf of Michael Maggiulli of the Technische Universitaet, Berlin24. It is hoped this material will contribute to a European Union funded programme concerned with microbial biodiversity in deep-sea sediments. Material was retained from a number of the West of Shetland transect sites (Tr250, 300, 350, 800, 900, 1000, 1100, 1200, 1250, 1300, L5, S2). Superficial sediment material from Megacores was retained both cool (c. 4ºC) and Formalin preserved from each of these site.

Hydrocarbons

(a) Five replicate sets of duplicate hydrocarbon samples were taken at sites FSC10 (deep Faroe-Shetland Channel) and T3-69 (Fladen Ground, North Sea), i.e. two standard hydrocarbon samples (see above) from separate cores were collected from five separate deployments of the Megacorer at each location.

(b) A quintuplicate set of hydrocarbon samples was taken from site T3-73 (Fladen Ground, North Sea), i.e. five standard hydrocarbon samples (see above) were collected from a single deployment of the Megacorer.

Sediment profile chemistry

A detailed study of the vertical distribution of standard sample parameters (hydrocarbons, heavy metals and particle size) was undertaken across a number of sites in the Fladen Ground area (Sites T3-55, 59, 61, 63, 65, 67, 69, 71, 73, 75, 77, 80, T6-1 to 8, ALBA3 and 4). Megacore samples were sectioned in to 0-2, 2-5, 5-10, 10-15, 15-20, 20-25 and 25-30cm sediment horizons and then treated as per standard sampling protocol (see above).

‘Speciality’ chemicals

Additional material for the study of various organic compounds was collected across a number of sites in the Fladen Ground area (Sites T3-55, 59, 61, 63, 65, 67, 69, 71, 73, 75, 77, 80, T6-1 to 8 and ALBA 4). Megacore samples were treated as per the standard hydrocarbon sampling protocol (see above) to produce this material.

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Michael Maggiulli, technische Universitaet Berlin, Inst. Fuer Land- und Seeverkehr, FG Maritime Technik, Mueller-Breslau-Str. D-10623 Berlin, Germany. Tel. +49 30 31184280, Fax. +49 30 31184200, e-mail [email protected]

Radioisotopes

Samples intended for the study of radioisotopes were collected from five replicate deployments of the Megacorer at Site T3-73 (Fladen Ground, North Sea). In each case the Megacore sample was sub-cored using a BGS gravity core liner and the c. 0-30cm sediment horizon retained.

Geology

(a) Gravity cores were collected at a number of sites visited during the cruise:

Survey Sites Samples

Ymir Ridge YR14 1

Wyville Thomson Ridge WTS8 1

Faroe Bank Channel R2 1

West of Shetland contourite study BGSAS1, 2, BGS1, 3, 4 6

Texaco survey TX1, 2 2

North of Shetland area (Tranches 65-67) BGS1, 4, SBB3, WFA1, 2, 3 6

Fladen Ground (North Sea) T3-73 3

This material was processed by the BGS representative aboard (C3, Tappin; C4, Tulloch); further information on this material should be sought from the British Geological Survey25. Typically gravity cores were split, sampled for organic geochemistry, subject to geotechnical tests, visually logged, photographed and archived.

(b) Other material for geological study was obtained variously from Day grab, box core and Megacorer samples at numerous survey sites (see Sections 8 and 9). Day grab material provided the opportunity for visual logging and collection of bulk superficial sediment samples. Box core samples were typically assessed from sub-cores taken with a complete or half-round section of gravity core liner. Megacorer samples were typically assessed by extruding the sediment column in to a second Megacorer tube that had previously been sectioned vertically in to two half-round profiles. The geological samples were generally subject to:

(i) visual examination (e.g. grain size; colour; sorting; grain shape and roundness; foraminiferan content; carbonate content; depth of any oxidation band; evidence for bioturbation; thickness; photographed)

(ii) geotechnical testing (e.g. hand-held penetrometer and hand-held shear vane) (iii) sampling (e.g. for bulk density, dry density and moisture content)

(iv) archiving (e.g. material retained).

Additionally a number of samples intended for geological study were also retained by SOC (see Sections 8 and 9).

Frozen cores

A number of intact whole cores were frozen as general archive material from several of the West of Shetland transect sites (Tr350, 450, 550, 600, 800, 900, 1000, 1100 1250, 1300, L4, 5, S2).