The major aims of Charles Darwin cruise 178 were to obtain: (i) 3D seismic imagery, video transects and swath bathymetry maps of mud volcanoes in the southern Gulf of Cadiz, (ii) video transects across suspected cold water coral reefs in the Alboran Sea, and (iii) 3D seismic imagery of submarine landslides in the Eivissa Channel, immediately east of the Balearic Islands in the western Mediterranean Sea. The cruise was in support of the EU Framework 6 'HERMES' project (Hotspot Ecosystem Research on the Margins of European Seas). A total of four 3D seismic cubes and 10 successful video transects were completed. Live chemosynthetic communities found on one mud volcano in the Gulf of Cadiz appear to indicate active methane seepage. Images of gas-charged sediments in areas of submarine landsliding in the Eivissa Channel appear to indicate a direct linkage between landsliding and fluid escape.
The cruise is a component of RAPID-WATCH, whose objectives are: to deliver a decade-long time series of calibrated and quality-controlled measurements of the Atlantic MOC from the RAPID-WATCH array and; to exploit the data from the RAPID-WATCH array and elsewhere to determine and interpret recent changes in the Atlantic MOC, assess the risk of rapid climate change, and investigate the potential for predictions of the MOC and its impacts on climate. Objectives of this cruise: to recover, calibrate and redeploy moorings from the eastern boundary and mid-Atlantic ridge subarrays of the 26.5N line of RAPID moorings.
Cruise D344 was primarily used for the annual servicing of the eastern boundary and mid-Atlantic ridge moorings that form part of the RAPID-MOC mooring array across the North Atlantic at 26°N. In addition, the easternmost western boundary mooring, WB6, was serviced and the trial current meter mooring off the island of Abaco, WB-CM, was recovered. As the Discovery had made a faster passage than anticipated, a number of CTD stations were performed along 24° 30'N to augment the hydrography section scheduled to take place in January 2010. The instruments deployed on the RAPID-MOC array consist of bottom pressure recorders, CTD loggers, and current meters which, combined with time series measurements of the Florida Channel Current, and wind stress estimates, will be used to determine the strength and structure of the MOC at 26.5°N.
This equipment trials cruise has provided opportunities for test and verification of technology under development at the Proudman Oceanographic Laboratory (POL), the Scottish Association for Marine Science (SAMS) and the National Oceanography Centre, Southampton (NOC,S). This includes equipment developed during the first year of funding under OCEANS 2025 (theme 8). Testing technology in the ocean environment is invaluable in assessing fitness for purpose. Specifically, the cruise tested: A Spar wave buoy (NOC,S) biogeochemical sensors (NOC,S); an UAV system (NOC,S); a video grab system "HyBis" (NOC,S), A benthic Multicore (NOC,S), A benthic lander and associated torroidal Telemetry buoy (POL), and a shallow tow towfish (POL). Testing in Spanish waters (near Tenerife, Gran Canaria and Fuerteventura) has been invaluable. The time on passage has been minimised (the transition from deep to shallow water is less than a days steaming) and the calm conditions to the southwest of the islands in the consistent prevailing north easterly winds have enabled deployment and recovery techniques to be tried and optimised in safety.
The objective of cruise DY039 was to service the moorings of the RAPID 26°N project that are deployed to monitor the Atlantic Meridional Overturning Circulation. For each mooring instruments were recovered, data were downloaded and instruments were redeployed. A number of CTDs were made to calibrate the instruments from the moorings. In addition to the standard instruments used in previous years on the RAPID array, biogeochemical instruments were deployed for the ABC Fluxes project, along with some additional temperature sensors and ADCPs for the MerMeed project. During passage from Southampton to Tenerife trial CTDs were completed in international waters. After a short port call in Santa Cruz de Tenerife, departing on the 26th October work commenced on the eastern boundary sub-array comprising of moorings EBH4, EBH4L, EBH3, EBH2, EBH1, EBH1L, EBHi, EB1 and EB1L. A lander was deployed alongside EBHi to provide delayed-mode data telemetry through timed data pod release. Work on the MAR sub-array commenced on 7th November at mooring MAR3. The other moorings in this sub-array (MAR3L, MAR1, MAR1L, MAR2 and MAR0) were all completed by 12th November. The NOG mooring was also recovered and redeployed as part of the MAR sub-array servicing. Mooring WB6 was serviced on 19th November before transiting to Nassau for customs clearance. The remaining western boundary sub-array moorings (WBADCP, WBAL, WB1, WB2, WB2L, WBH2, WB4 and WB4L) were serviced between the 22nd November and the 30th November before docking in Nassau on the 1st December.
The aim of this cruise was to develop a better understanding of carbon cycling in the pelagic waters of the Porcupine Abyssal Plain (PAP). There were three objectives: 1) Turnaround moorings at the PAP Observatory; 2) Conduct a 1-D time series on the central station of a wide range of biogeochmical processes and to back this up with a mesoscale survey of key variables; 3) To trial the use of Autosub for mesoscale surveys in conjuction with the ship. All objectives were met, although the tops of the moorings were found to be missing probably due to fishing activity and the Autosub trials were incomplete due to vehicle failure. A full mesoscale survey was carried out using the ship and an eleven day time series at the central station was achieved. Friday 23 June [JD174] Scientific party met at 13:00 to agree work plans. The Master gave welcome & safety talk at 15:00. We sailed at 18:00 after a series of delays. The Chief Officer was discharged off sick and a replacement was travelling from Lincolnshire. On reaching Plymouth, the railway shut due to a suicide on the track. The replacement mate required taxi from Plymouth to Falmouth. One of the ship's cranes broken, compromising our ability to handling moorings. The ship's engineers worked flat out yesterday and today and managed to cannibalise parts from other cranes. On sailing we moved into the lee of Falmouth Bay to carry out ship's compass check and then deployed Autosub briefly to check its sensors were working. The sea-state was surprisingly benevolent considering how hard the wind had been blowing for previous 3 days. The skies were still very cloudy. Saturday 24 June [JD175] We made an easy passage with winds BF 3-4. The scientists were finding their sea-legs, with no major problems. An Emergency muster & life boat drill was run at 10:30. We had a discussion about Autosub mission and decide to work the central box at PAP for the first deployment.
CTD stations on 20W line from 50N to 20N, following the old WOCE line A16N Physical measurements (CTDO and LADCP) and discrete samples for salt, oxygen, inorganic nutrients and alkalinity/inorganic carbon Underway ADCP, surface ocean measurements, surface meteorology measurements. Contribution to GO-SHIP sustained hydrography program. Partial repeat of a hydrographic line last occupied in 2003.
This project was a hydrographic section at latitude 24°N, with physical, chemical and biological measurements. The section was a complete section from continent to continent from North America (Caribbean) to Africa (off the coast of the Western Sahara). The section started and ended in 200 metres water depth, at the edge of the continental shelf. This was a contribution to the international CLIVAR/Carbon repeat hydrography program (http://ioc3.unesco.org/ioccp/Hydrography/New_GlobalMap.html). Climate change will be studied by comparing the new data with historical measurements. Ocean heat transport plays a major role in the coupled ocean-atmosphere climate system. We will study the present-day circulation by calculating the heat and freshwater transported by the ocean across the 24°N latitude. The ocean western boundary current system, in this case the Gulf Stream flowing through the Florida Strait, plays a crucial role in the oceanic heat transport. Therefore a crossing of the Florida Strait will be carried out to establish the status of this important ocean feature. All data arising from the cruise will be lodged and made available via the British Oceanographic Data Centre (BODC), UK.
The goal of this cruise was to recover and redeploy some RAPID-MOC moorings near the Eastern Boundary as part of our six-month turnaround programme. Specific cruise objectives were to: 1. Recover moorings EB1 (24 microcats) and EB2 (MMP profiling from 50m to 2500m with microcats and current meters below), two principal tall eastern boundary moorings, sited on a Topex crossover point near 24N, 24W. 2. Redeploy EB1 (24 inductive microcats plus the telemetry system) and EB2 (MMP mooring). 3. Deploy EBADCP to replace the instrument deployed in April but trawled after 10days and recovered by the R/V Poseidon. 4. Deploy two URI Pressure Inverted Echo Sounders. One deployed in 1000m and one in 5000m next to the BPR lander at mooring EB1. 5. CTD stations for pre and post deployment calibrations of all mooring instrumentation. 6. Search for and if possible recover MMP mooring EB2 deployed in April 2004 and located 100km north south of Gomorra in October 2004.
The RRS Discovery cruise 304 was conducted from 12 May to 6 June 2005 from and to Santa Cruz (Tenerife). The cruise was completed as part of the NERC founded RAPID programme to monitor the meridional overturning circulation at 26 N. The primary purpose was to service the eastern boundary and Mid-Atlantic Ridge part of the 26 N mooring array which had previously been serviced during the RRS Charles Darwin cruises 170 and 177. 12 moorings were successfully recovered, however two of the shallow eastern boundary moorings failed to release. Intense fishing activity at these sites is likely to be the cause. 12 mooring and four bottom pressure landers were re-deployed. Data from two bottom mounted inverted echosounders was uploaded via acoustic telemetry. A total of 10 CTD casts to calibrate the mooring sensors were carried out and 3 Argo floats (from the UK Met Office) were launched. The moored sensors are CTD loggers for the most part but also bottom pressure sensors, different types of current meters and inverted echosounders are used to determine the strength and structure of the meridional overturning circulation.