RRS James Clark Ross JR17003A
Cruise summary report
| Cruise Info. | |
| Ship name (ship code) | RRS James Clark Ross (74JC) |
| Cruise identifier | JR17003A |
| Cruise period | 2018-02-22 — 2018-03-12 |
| Status | Completed |
| Port of departure | Stanley, Falkland Islands (Malvinas) |
| Port of return | Stanley, Falkland Islands (Malvinas) |
| Purpose | Research |
| Objectives | On 12 July 2017, the Larsen-C Ice Shelf calved the largest iceberg originating from the Antarctic Peninsula ever recorded. As A68 moves north, it will leave an area of 5,800 km^2 of seabed newly exposed to open-marine conditions. Much of this area has very likely remained ice-covered for centuries and may have been covered since the last inter-glacial period. The calving of A68 offers a unique and short-lived scientific opportunity to establish a fundamental research programme to address questions around the mobility and colonisation capacity of benthic marine species. Our governing hypothesis is: H: "Until the calving of the Larsen-C iceberg, A68, the benthic fauna on the seabed beneath ice shelf has likely comprised oligotrophic assemblages resembling deep-sea Weddell Sea assemblages. The calving of A68, and the exposure of the seabed it covered to open-marine and sea-ice conditions will initiate a rapid colonisation by new species that will transform the benthic ecosystem significantly within 3-5 years." Testing this hypothesis, including through follow up cruises from the international community will allow us to determine the baseline, sequence, rate and degree of colonisation, understand the mechanisms of transport of these benthic species, and the sequence of their colonisation. This will allow us to improve fundamental understanding about the resilience of polar continental shelf ecosystems, improve interpretations of marine sediment records, and support effective ecosystem management regulation. We will deploy trawls, corers, cameras, salinity and depth sensors, and echo-sounders to measure mid-water zooplankton assemblages and map the seabed terrain. As JR17003a was targeting a research area of high risk to be effected by adverse sea-ice conditions that can deny access to the proposed research area, contingency plans were in place for different scenarios and the scenario "Not reach Larsen area, so work would focussed on sites north of Larsen selected following a benthic biodiversity knowledge review in biodiversity.aq" had to be taken as thick, multi-year pack-ice with tilted and re-frozen floats forming high press-ice ridges forced the cruise to turn back and proceed with the same sampling strategy in Prince Gustav Channel, where the southern end had been covered by the Larsen-A ice-shelf until 1989-1993. |
| Chief scientist | Katrin Linse (British Antarctic Survey) |
| Project | Benthic biodiversity under Antarctic ice-shelves |
| Coordinating body | British Antarctic Survey (BAS) |
| Cruise report |  (7.86 MB) |
| Ocean/sea areas | |
| General | South West Atlantic Ocean (limit 20W) Southern Ocean |
| Specific | Prince Gustav Channel, Eastern Antarctic Peninsula, Western Weddell Sea. |
| Track charts | (0.06 MB) |
| Measurements | |
| Physical oceanography | |
| Surface measurements underway (T,S) | Quantity: activity duration in days = 15 Description: T, S underway surface measurements |
| Water bottle stations | Quantity: number of deployments = 8 Description: CTD casts. Continuous recordings conductivity, temperature, depth, fluorescence, PAR, transmittance. Lowered ADCP. Discrete bottle samples Oxygen, eDNA, POC, phytoplankton pigments |
| CTD stations | Quantity: number of deployments = 8 Description: CTD casts. Continuous recordings conductivity, temperature, depth, fluorescence, PAR, transmittance. Lowered ADCP. Discrete bottle samples Oxygen, eDNA, POC, phytoplankton pigments |
| Current profiler (eg ADCP) | Quantity: number of deployments = 8 Description: CTD casts. Continuous recordings conductivity, temperature, depth, fluorescence, PAR, transmittance. Lowered ADCP. Discrete bottle samples Oxygen, eDNA, POC, phytoplankton pigments |
| Chemical oceanography | |
| Oxygen | Quantity: number of deployments = 8 Description: CTD casts. Continuous recordings conductivity, temperature, depth, fluorescence, PAR, transmittance. Lowered ADCP. Discrete bottle samples Oxygen, eDNA, POC, phytoplankton pigments |
| Contamination | |
| Other contaminant measurements | Quantity: number of deployments = 7 Description: MUC cores for microplastics in sediment |
| Biology and fisheries | |
| Phytoplankton pigs (eg chlorophyll, fluorescence) | Quantity: number of deployments = 8 Description: CTD casts. Continuous recordings conductivity, temperature, depth, fluorescence, PAR, transmittance. Lowered ADCP. Discrete bottle samples Oxygen, eDNA, POC, phytoplankton pigments |
| Particulate organic matter (inc POC, PON) | Quantity: number of deployments = 8 Description: CTD casts. Continuous recordings conductivity, temperature, depth, fluorescence, PAR, transmittance. Lowered ADCP. Discrete bottle samples Oxygen, eDNA, POC, phytoplankton pigments |
| Particulate organic matter (inc POC, PON) | Quantity: number of deployments = 9 Description: MUC cores for particulate organic matter and benthic bacteria/micro-organisms |
| Particulate organic matter (inc POC, PON) | Quantity: number of deployments = 3 Description: Bongo deployments with zooplankton and particulate organic matter |
| Zooplankton | Quantity: number of deployments = 3 Description: Bongo deployments with zooplankton and particulate organic matter |
| Benthic bacteria/micro-organisms | Quantity: number of deployments = 8 Description: CTD casts. Continuous recordings conductivity, temperature, depth, fluorescence, PAR, transmittance. Lowered ADCP. Discrete bottle samples Oxygen, eDNA, POC, phytoplankton pigments |
| Zoobenthos | Quantity: number of deployments = 22 Description: MUC (9), C-EBS (7) and AGT (6) deployments for zoobenthos, including demersal fish, molluscs and crustaceans |
| Birds | Quantity: activity duration in days = 15 Description: Marine mammal and bird surveys |
| Mammals and reptiles | Quantity: activity duration in days = 15 Description: Marine mammal and bird surveys |
| Demersal fish | Quantity: number of deployments = 22 Description: MUC (9), C-EBS (7) and AGT (6) deployments for zoobenthos, including demersal fish, molluscs and crustaceans |
| Molluscs | Quantity: number of deployments = 22 Description: MUC (9), C-EBS (7) and AGT (6) deployments for zoobenthos, including demersal fish, molluscs and crustaceans |
| Crustaceans | Quantity: number of deployments = 22 Description: MUC (9), C-EBS (7) and AGT (6) deployments for zoobenthos, including demersal fish, molluscs and crustaceans |
| Acoustic reflection on marine organisms. | Quantity: activity duration in days = 15 Description: EK60 multifrequency acoustic backscatter collected at 38, 120 and 200 kHz. |
| Other biological/fisheries measurement | Quantity: number of deployments = 22 Description: MUC (9), C-EBS (7) and AGT (6) deployments for zoobenthos, including demersal fish, molluscs and crustaceans |
| Geology and geophysics | |
| Core - soft bottom | Quantity: number of deployments = 5 Description: MUC cores for sediment grain size analysis |
| Bottom photography | Quantity: number of deployments = 20 Description: High resolution photographs and video of seabed for biodiversity measurements |
| Single-beam echosounding | Quantity: activity duration in days = 15 Description: EM122 swath bathymetry data. Instrument calibrated in Falkland Trough at start of expedition. |
| Multi-beam echosounding | Quantity: activity duration in days = 15 Description: EM122 swath bathymetry data. Instrument calibrated in Falkland Trough at start of expedition. |
