Cruise inventory
RRS James Clark Ross JR20101221 (JR245, JR246, JR247)
Cruise summary report
| Cruise Info. | |
| Ship name (ship code) | RRS James Clark Ross (74JC) |
| Cruise identifier | JR20101221 (JR245, JR246, JR247) |
| Cruise period | 2010-12-21 — 2011-01-19 |
| Status | Completed |
| Port of departure | Stanley, Falkland Islands (Malvinas) |
| Port of return | Stanley, Falkland Islands (Malvinas) |
| Purpose | Research |
| Objectives | Cruises JR245, 246 and 247 were amalgamated into one cruise. JR245 was 19 days of the Western Core Box cruise, JR246 was 2 days of Hotspots and JR247 was 7 science days for an AFI project (The role of krill grazing in Southern Ocean nutrient cycles). In addition there was an AFI-CGS (Individual physiological and behavioural responses of krill to distributional shifts and thermal change) project undertaken. All three projects were focussed on investigating Antarctic krill (Euphausia superba) and it was therefore sensible to combine them into one cruise focused around South Georgia.
JR245 Western Core Box Since 1981 BAS have undertaken cruises to determine krill biomass as part of the ongoing assessment of the status of the marine ecosystem in the region of South Georgia. This unique time series, known as the “Western Core Box” is part of the Ecosystem Programme contribution to BAS' national capability. It is comprised of an acoustic grid survey of 8 transects each of 80 km in length, together with associated net and oceanographic sampling and the calibration of the acoustic instrumentation. In addition to the acoustic survey, which covers a wide area but has limited temporal coverage, there are three moorings (one in the Western Core Box and one south and one north of South Georgia) to provide a temporal context. These moorings are typically recovered and redeployed during the WCB survey. Due to the lack of gantry this year the moorings were not recovered or redeployed. JR247 The role of krill grazing in Southern Ocean nutrient cycles Even though Antarctic krill are a key species in the Southern Ocean food web and commercially fished for, little is known about their role in biogeochemical cycles. This AFI project will test the hypothesis that Antarctic krill help to promote the drawdown of CO2 from the atmosphere to the deep ocean by enhancing the biological carbon pump. It will address (a) how much carbon, nitrogen, silica and iron are in krill fecal pellets, (b) do the elements dissolve out of the pellets before sinking to depth, (c) do krill accumulate iron in their bodies and (d) how much iron and nitrogen do krill release in dissolved form when feeding. AFI-CGS Individual physiological and behavioural responses of krill to distributional shifts and thermal change The physiology of krill is considered to be stenothermal, operating most efficiently within a narrow temperature range of between 0 and 2C. South Georgia is a krill rich region, but recent reports have indicated there has been a mean increase of 0.9C in its surface waters over the past 81 years. Trend analyses have also pointed to a significant negative relationship between summer South Georgia temperatures and mean summer density of krill, predicting a decline in the suitability of this area as a future krill habitat. The physiological response of krill to temperature change will be investigated through analysis of aerobic respiration and other indicators of performance. |
| Chief scientist | Sophie Fielding (British Antarctic Survey) |
| Project | Ecosystems |
| Cruise report |  (3.86 MB) |
| Ocean/sea areas | |
| General | South Atlantic Ocean |
| Specific | South Atlantic Ocean and Scotia Sea. |
| Track charts | (0.88 MB) |
| Measurements | |
| Physical oceanography | |
| Surface measurements underway (T,S) | Quantity: number of track lines = 1 Description: Underway - ships non toxic pumped sea water supply |
| Bathythermograph | Description: XBT |
| Water bottle stations | Description: CTD |
| CTD stations | Description: CTD |
| Current profiler (eg ADCP) | Description: ADCP |
| Chemical oceanography | |
| Trace elements | Description: Go-flo bottles (clean water) varying depth |
| Trace elements | Description: Towed iron fish underway sea water supply |
| Trace elements | Description: SAPS – time period pumping through filter |
| Biology and fisheries | |
| Phytoplankton pigs (eg chlorophyll, fluorescence) | Quantity: number of track lines = 1 Description: Underway - ships non toxic pumped sea water supply |
| Zooplankton | Description: Bongo net – obliquely hauled |
| Zooplankton | Description: Custom 1m Net - Krill feeding and egestion incubations |
| Zooplankton | Description: Custom 1m Net – krill length measurements, krill oxygen respiration rates & calorific value |
| Zooplankton | Description: Custom 1m Net – Krill swimming and tail flip response to stimulus |
| Nekton | Description: Custom 1m Net – Themisto swimming |
| Meteorology | |
| Routine standard measurements | Description: Onboard ships meteorological |
| Geology and geophysics | |
| Single-beam echosounding | Description: EA600 Single Beam |
| Multi-beam echosounding | Description: EK60 Multi-beam |
