Real-Life Communication

Many people around the world are helping to map and analyze our planet's oceans. Often, scientists from universities and research institutes in different countries will work together on research projects. Together, they will go out to sea on cruises that can last for months. They gather samples from the surface of the ocean and the depths.

Many of the reports from these cruises are available on the Internet. It's a convenient way for researchers to tell others about the work they are doing. But the reports aren't just for professors and researchers! If you have an interest in science, you'll be fascinated by the information in these reports. You don't have to be an expert to read them and understand most of what they say.

You will find a cruise report from a research trip below.

Read it carefully. Then write a summary of less than 200 words describing the cruise. Answer these questions: Who was on the cruise? What does WOCE stand for and what is the fieldwork WOCE hopes to accomplish? What was the route of the cruise and what underwater geological formations are mentioned in the report? What was the team looking for in the water samples?

WHP Ref. No.: A8
Initial Cruise Report
METEOR Cruise 28/1

A. Cruise narrative

A.1. Highlights

1. WOCE designation: A8
2. Expedition designation: 06MT28/1
   • Meteor 28 leg 1
3. Chief scientist:

   Thomas J. Mueller
   Institut fuer Meereskunde an der Universitaet Kiel
   Germany

4. Ship: Meteor
5. Ports of call: Recife, Brazil - Walvisbay, Namibia
6. Cruise dates: March 29 - May 11, 2003

A.2. Cruise Summary Information

1. Geographic boundaries: METEOR Cruise 28/1 was designed to work the transatlantic section A8 along 11 20'S as part of the World Ocean Circulation Experiment (WOCE).
2. Stations occupied: On the section, 110 full-depth stations with CTD and up to 40 bottle samples per station were obtained. Water samples were analyzed onboard for salinity, oxygen, nutrients and carbon dioxide.

   In addition, underway measurements of currents and meteorological data, as well as near surface temperature and salinity were performed. Near surface plankton hauls on 69 stations and filtration of aerosols were programs not directly related to WOCE. Processing and analysis of data are in progress and preliminary.

3. Floats and drifters deployed: Satellite tracked drifters were deployed on this cruise but details are not yet available.
4. Moorings deployed or recovered: No moorings were deployed or recovered on this cruise.

A.3. List of Principal Investigators

Principal Investigator	Institution	Measurement
Mueller, Thomas J.	IFMK	chief scientist, CTD
Hydes, David	IOSDL	oxygen, nutrients
Roether, Wolfgang	UB	CFCs, helium/tritium
Johnson, Kenneth M.	BNL	CO2
Siedler, Gerold	IFMK	ADCP, lowered ADCP
Siedler, Gerold	IFMK	XBT, XCTD, XCP
Knutz, T.	IAPK	GEK
Krauss, W.	IFMK	Drifters
John, H.-C.	BAH	zooplankton
Jaenicke, K.	UMZ	atmospheric physics, DMS

Institutions:

BAH: Biologische Anstalt Helgoland, Zentrale Hamburg, Germany

BNL: Brookhaven National Laboratory, Brookhaven, NY, USA

IFMK: Institut fuer Meereskunde an der Universitaet Kiel, Germany

IOSDL: Institute of Oceanographic Sciences, Wormley, UK

UB: Universitat Bremen

UMZ: Meteorologisches Institut der Universitaet Mainz, Germany

A.4. Scientific Program and Methods

The main program of this leg was devoted to the World Ocean Circulation Experiment (WOCE) which is internationally coordinated by the World Meteorological Organization (WMO) and the International Council of Scientific Unions (ICSU).

Within the fieldwork of WOCE, for the first time in history the present state and dynamics of the ocean will be observed worldwide within less than 10 years. Closely related to WOCE is the Joint Ocean Global Flux Studies (JGOFS) within which sampling of CO₂ components is requested on WOCE hydrographic sections.

One major component of WOCE is the Hydrographic Program (WHP). German institutes took responsibility to occupy three zonal transatlantic hydrographic sections in the South Atlantic: Sections A9 along 19 S and A10 along 30 S were obtained during METEOR cruises 15/3 in 1991 and 22/5 in 1993, respectively.

During the present METEOR cruise 28/1, section A8 along nominal 11 20'S was occupied with a total of 110 hydrographic stations with CTD and up to 40 small (10 l) volume rosette samples per station. The nominal station spacing was decreased down to 10 nm and 5 nm over the shelf and continental breaks, to 24 nm over the Mid-Atlantic Ridge, and increased to 38 nm over the deep Pernambuco and Angola Basins. Bottle samples to analyze for oxygen, nutrients and salinity were taken on each station, samples for anthropogenic tracers and CO₂ on each second station. In addition, four test stations and a survey with ADCP were performed off the Brazilian shelf before the WHP section began, and a box around the eastern tail of the section was occupied.

As part of a long-term Atlantic wide survey on the distribution and ecology of fish larvae, biological stations with 69 plankton hauls from the surface and in five levels between the surface and 200 m depth were performed.

Aerosols determine the formation of clouds. Over the South Atlantic several sources may be expected: aerosols of sea salt and remainders of continental aerosols of mostly desertal origin as well as particles which result from decomposition of DMS formed by chlorophyll in the sea. All types of these aerosols were filtered from air and are to be correlated to DMS concentrations in sea water and air.

Narrative

METEOR sailed from Recife March 29 at 14:15 lt (19:15 UTC). Heading eastwards (see map attached), outside the 12 nm zone of Brazil at position 08 17'S, 34 30'W the continuously recording systems were switched on: the integrated system DVS to acquire navigational data, from the shipborne 150 KHz ADCP, and the towed GEK. As for earlier cruises, there was no clearance applied for surface meteorological and sounding data, because these were thought to be standard parameters always sampled like position. Contrary to these earlier cruises, these data were not allowed by the Brazilian observer to be acquired within the 200 nm Brazilian economic zone.

The first two days were designed to test both CTD systems, each equipped with a 24x10 l rosette sampler, on four deep water stations (no. 165 to 168). Also, the analysing systems for oxygen, nutrients, freons and CO₂ were set up. At 11 20'S, 034 00'W we began a section along A8 shorewards with XBT and XCP thereby achieving a box with ADCP and GEK in the divergence zone of the western branch of the South Equatorial Current.

On April 01, WHP section A8 started on position 10 03'S 35 46'W on the 200 m depth contour outside the 12 nm zone of Brazil normal to the continental break with station no. 169. On each of the following stations, together with the first CTD rosette, an 150 KHz self-containing ADCP was lowered (LADCP) to maximal 1000 depth. The bottles were used to increase the number of samples up to 40, where the bulk came from the main CTD which always went down until 10 m above the bottom. Until at 034 00'W the nominal latitude 11 20'S was reached again (no. 181), 13 stations at 5 nm to 20 nm spacing were obtained. Station spacing now was increased to 30 nm until 32 00'W (no.185).

Here, outside the 200 nm economic zone of Brazil, measurements with the multibeam echosounding system HYDROSWEEP, SST, SSS, surface meteorological data, and sampling of aerosols began. Over the Pernambuco Basin, station spacing was increased to 38 nm with XBT's of type T5 (nominal depth 1800 m at 6 Kn) launched halfway in between. Until no. 190 at 025 20'W, all stations were biological, too. From then on, spacing for biological hauls was 70 to 90 nm. Four satellite tracked surface drifters which are drogued at 100 m depth were launched between 020 00'W and 015 45'W.

Approaching the Mid-Atlantic Ridge, from 022 00W on (no. 200) spacing was decreased to 30 nm until 017 00'W (no. 210) and down to 24 nm over the ridge until 012 00'W (no. 222).

Spacing was increased again towards the Angola Basin to 28 nm until 001 00'W where the section ran close to the Dampier Seamount. Expecting higher hydrographic variability and different species of fish larvae, two extra CTD stations (no. 245, no. 247, no bottles) and plankton hauls were obtained.

From 000 00'E on station spacing increased over the Angola Basin to 38 nm until we reached the African continental break at 008 00'E (no. 260). Again, on this wider spaced part of the section XBT T5 probes were launched halfway between stations. Also, four more satellite drifting buoys were launched between 1 20'E and 005 20'E.

With 28 nm station spacing we reached 10 00'E (no. 264) where we entered the 200 nm economic zone of Angola. Since no clearance had been applied for plankton hauls, XBT, XCP and GEK, we had to continue with CTD measurements only. Station spacing was reduced first to 25 nm and then to 10 nm until we reached the 50 nm zone at 012 57'E (no. 274). Waiting for an extension of the clearance to 12 nm and plankton hauls within 200 nm which was to be arranged by the German embassy in Luanda, Angola, we surveyed the northern part of a box around the eastern tail of A8 using the CTD/LADCP system down to 1000 m depth (no. 275 to 281 along 11 00'S). We completed this box in the south (no. 282 to 286 along 11 40'S) after the extension of the clearance came with plankton hauls as well. We joined A8 again after two days interruption on 11 20'S at 13 05'E (no. 287) and completed it on the 200 m depth contour at 13 33'E with no. 290 on May 07, 2003.

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