Cruise Report: JR 144, 145, 146, 147 and 149
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Cruise report: JR 144, 145, 146, 147 and 149 Stanley 26.02.2006 – Montevideo 17.04.2006 PSO: Dr. Katrin Linse, BAS This report contains initial observations and conclusions. It is not to be cited without the written permission of the Director, British Antarctic Survey Cruise report: JR 144, 145, 146, 147 and 149 Stanley 26.02.2006 – Montevideo 17.04.2006 1. Introduction 1.1. Objectives of the cruise (Linse, K.) 1.2. Cruise plot 1.3. Cruise participants 2. JR 144 (Linse K. et al.) 2.1. Vertical transects 2.1.1. AGT 2.1.2. EBS 2.1.3. RBOT 2.2. Diving 2.3. Temperature induced changes in gene expression 2.4. Microbial water sampling 2.4.1. META-genomic CTDs 2.4.2. Microbial CTDs 2.5. Terrestrial collections 3. JR 145 (Rock, J. et al.) 3.1. Trammel nets 3.2. Otter trawls 4. JR 146 (Enderlein, P.) 4.1. WCB 4.2. Moorings 5. JR 147 (Strugnall, S.) 6. JR 149 (Allen, C. S. et al.) 6.1. Swathing 6.2. Under-way water sampling 6.3. Piston coring 7. ITS & AED (Edmonston, J. & Afanaseyev, V.) 8. Annexes 8.1. Event logs 8.1.1. Bridge event log 8.1.2. Trawled gear 8.1.3. CTD 8.1.4. Coring 8.1.5. WCB 8.2. AGT catch photos 8.3. Zoobenthos samples 8.3.1. AGT samples 8.3.2. RBOT samples 1. Introduction 1.1. Objectives of the cruise (Linse, K.) Special relationships exist between the waters around the southern part of South America, the Magellan Province, and the waters around the Subantarctic islands and the Antarctic continent. They have their origin in the common past of these regions as part of the Gondwana continent and in their close vicinity up to the present day as compared to the distances between Antarctica and the other surrounding continents. Both factors, as well as the actual isolation of Antarctica by deep water and the current system, and periods of interchange, radiation and extinction in the past, are reflected in the present-day marine biota on either side of the Drake Passage. This context represents a singular case of ecosystem change and evolution on our planet, and a great challenge to research. Biological work was to concentrate on seven areas along the Scotia Arc where a whole range of trawling equipment (AGT, EBS, RBOT) was to be employed, supported by CTDs. At a number of additional stations, only CTDs were to be taken to provide more material for answering bacterial and microbial biodiversity issues. Hydrosweep was to be used to better recognize small-scale topographic patterns at the seafloor and avoid losses of gear. At four areas diving took place to collect selected target species for studies on heat introduces changes in gene expression. In the Western Core Box, part of the BAS LTMS program, the abundance of zooplankton in the water column was measures by acoustic means on six of eight planned transects and two moorings for year-round zooplankton measurements were recovered and redeployed. Geological work concentrated on piston coring at two selected deep-sea sites (NW of South Orkney Islands, NE of South Georgia), under-way water sampling to assess the recent diatom communities for comparison with past ones form the piston cores and under-way swath bathymetry. 1.2. Cruise plot 1.3. Cruise participants Overall PSO: Dr. Katrin Linse, British Antarctic Survey JR 144 PSO: Dr. Katrin Linse, British Antarctic Survey Dr. David K.A. Barnes, British Antarctic Survey Mr. Matthew Brown, British Antarctic Survey Dr. Peter Enderlein, British Antarctic Survey Dr. Keiron P.P. Fraser, British Antarctic Survey Mr. Huw J. Griffiths, British Antarctic Survey Ms. Stefanie Kaiser, Zoological Institute and Museum, Hamburg Ms. Rachel Malinowska, British Antarctic Survey Dr. David Pearce, British Antarctic Survey Mr. Daniel Smale, British Antarctic Survey JR 145 PSO: Dr. Jennifer Rock, University of Wales, Bangor Mr. Alastair Newton, University of Wales, Bangor Dr. Anthony North, University of Wales, Bangor JR 146 PSO: Dr. Peter Enderlein, British Antarctic Survey JR 147 PSO: Dr. Jan M. Strugnall, QUB, Belfast/ British Antarctic Survey JR 149 PSO: Dr. Claire S. Allen, British Antarctic Survey Ms. Anna Hey, University of Wales, Cardiff Ms. Elizabeth Petrie, Scottish Association for Marine Science, Oban Mr. Richard Phipps, UCORS, Southampton ITS Mr. Johnny Edmonston AED Mr. Vsevolod Afanasyev 2. JR 144 (Linse, K. et al.) 2.1.Vertical transects 2.1.1. AGT (Linse, K., Griffiths, H., Barnes, D.K.A.) Objectives Our main aim was to sample macro-and mega- size fractions of seabed dwelling (benthic) animals along a latitudinal and bathymetric gradient in the Scotia arc. The sampling regime was designed to investigate patterns of biodiversity and biogeography of benthos in this key region of the Southern Ocean. One site was north of the Polar Front (Burdwood Bank) whilst the others lay to the south of this important boundary oceanographic feature. We trawled at four discrete depth horizons (approximately 200, 500, 1000 and 1500 m) to investigate variability of taxa presence from continental shelf to continental slope depths (thereby gaining insight into historical recolonisation after glacial maxima). As well as being the location at which several major biogeographic zones intersect the Scotia arc can be considered of vital importance at regional and global levels. It is the only link between ‘oceanographically and geographically-isolated’ Antarctica and other continents and shelves. It includes some of the best and least studied areas, the oldest and youngest islands, some of the fastest warming (land) sites, the most heavily impacted by man and includes the sites of the only known marine invasive species travelling to the Southern Ocean. It is truly a fundamental region of the world to have good baseline data for and to understand the dynamics of a most sensitive component of its fauna, the benthos. Our results will be compared with data collected in the Scotia arc, especially with those obtained during German and Spanish expeditions (e.g. Arntz et al. 1999, 2005, Ramos 1999). Work at sea An Agassiz trawl (AGT) was used to sample benthic mega- and macrofauna at seven depths transects (200m, 500m, 1000m and 1500m) in different regions of the Scotia arc (Fig. 2.1). The geographic areas chosen for the transects were the Falkland Trough, South Shetland Islands (Livingston and Elephant islands), South Orkney Islands (Powell Basin), South Sandwich Islands (Southern Thule), South Georgia and Shag Rocks. Figure 2.1. Scotia arc and AGT sample locations. Samples were collected using a 2 m wide Agassiz trawl. At most stations the seabed topography was examined prior to trawl deployment using multibeam sonar (SWATH). The deployment protocol was standardised. While the AGT was lowered, the ship had to compensate for the wire lowering speed of 45 mmin-1 by steaming with 0.3 knots until the AGT reached the seabed and with 0.5 knots until the full trawling wire length was put out. The full trawling cable length was 1.5 times the water depth. The net was then trawled at 1 knot for 10 min at 200m and 500m water depth and for 15 min at 1000m and 1500m water depth. With the ship stationary the AGT was hauled with 20 mmin-1 in order to avoid damaging the gear. When the EBS had left the seafloor, the hauling speed was increased to 45 mmin-1 and the ship speed to 0.3 knots. Once on board the samples were photographed as total catch and then hand-sorted into groups varying from Phylum to species level collections. Representatives of certain taxa were photographed in detail. The weight/biomass of the different taxa was assessed by using calibrated scales (0.000kg). Depending on the taxon, animals were either preserved in 96% ethanol, 4% buffered formalin or frozen at –20ºC. The following abbreviations are used in the text: DI – Deception Island, EI – Elephant Island, FT – Falkland Trough, LI – Livingston Island, PB – Powell Basin, SG – South Georgia, SR - Shag Rocks, ST – Southern Thule. Preliminary results One of the first analyses done after the AGT catches were sorted and fixed was to count the number of phyla present in the catch, to assess the phylum richness of the trawled area (Table 2.1). The presence of phyla varied between 2 (SR-AGT-5, 200m) and 12 (FT-AGT-1B, 200m); FT-AGT-1 is not counted, as the cod end opened in the water column and most of the catch was lost. With the exception of the Falkland Trough, where the most phyla were caught at 200m, the most phyla per transect were collected at either 1000m (twice) or 500m (4 times). Table 2.1. Absence and presence of Phyla in AGT catches STATION_ID Annelida Brachiopoda Bryozoa Chelicerata Chordata Cnidaria Crustacea Echinodermata Mollusca Nemertea Porifera Priapula Sipuncula Symplasma Total Grand DI-AGT-1 1 1 1 1 1 1 1 1 8 EI-AGT-1 1 1 1 1 1 5 EI-AGT-2 1 1 1 1 1 1 1 1 1 1 10 EI-AGT-3 1 1 1 1 1 1 1 1 1 9 EI-AGT-4 1 1 1 1 1 1 1 1 1 1 10 FT-AGT-1 1 1 FT-AGT-1B 1 1 1 1 1 1 1 1 1 1 1 1 12 FT-AGT-2 1 1 1 1 1 1 1 1 1 9 FT-AGT-3 1 1 1 1 1 1 1 1 1 1 10 FT-AGT-4B 1 1 1 1 4 LI-AGT-1 1 1 1 1 4 LI-AGT-2C 1 1 1 1 1 1 1 1 1 9 LI-AGT-3 1 1 1 1 1 1 1 1 1 1 1 11 LI-AGT-4 1 1 1 1 1 1 1 1 1 9 LI-AGT-5 1 1 1 1 1 1 1 1 1 9 PB-AGT-1 1 1 1 1 1 1 1 1 8 PB-AGT-1B 1 1 1 1 1 1 6 PB-AGT-2 1 1 1 1 1 1 1 1 8 PB-AGT-3 1 1 1 1 1 1 1 1 1 1 10 PB-AGT-4 1 1 1 1 1 1 1 1 1 9 SG-AGT-1 1 1 1 3 SG-AGT-2 1 1 1 1 1 5 SG-AGT-3 1 1 1 1 1 1 1 7 SG-AGT-4 1 1 1 1 1 1 1 1 1 1 10 SG-AGT-5 1 1 1 1 1 1 6 SR-AGT-1 1 1 1 3 SR-AGT-3 1 1 1 1 1 1 1 1 1 9 SR-AGT-4 1 1 1 1 1 1 1 1 1 1 10 SR-AGT-5 1 1 2 SR-AGT-6 1 1 1 1 1 1 1 7 ST-AGT-1 1 1 1 1 1 5 ST-AGT-2 1 1 1 1 1 1 1 1 1 1 1 11 ST-AGT-3 1 1 1 1 1 1 1 1 1 1 10 ST-AGT-4 1 1 1 1 1 1 1 1 1 9 Afterwards the number of Phyla, the dominant phylum by numbers of collected specimens and dominant phylum by biomass was evaluated (Table 2.2).