RRS Challenger CH17
Cruise summary report
| Cruise Info. | |
| Ship name (ship code) | RRS Challenger (74CH) |
| Cruise identifier | CH17 |
| Cruise period | 1987-07-06 — 1987-08-02 |
| Status | Completed |
| Port of departure | Troon, United Kingdom |
| Port of return | Plymouth, United Kingdom |
| Purpose | Research |
| Objectives | 1. To measure the concentrations and distribution of major nutrients in the North Sea with particular emphasis on the sea areas bordering the major estuaries.
2. To measure the rates of primary production and nitrogen assimilation of phytoplankton, and their horizontal distribution in relation to nitrogen inputs. 3. To measure the variations in the natural abundance of 15N in particulate and dissolved nitrogen and to relate these to the inputs and internal cycling of nitrogen. 4. To measure sedimentation rates of particular matter at selected sites in the North Sea. 5. To measure the rates of denitrification in the sediments of the North Sea. 6. To characterise the natural phytoplankton populations using shipboard flow cytometry. 7. To determine the distribution and concentrations of dissolved and particulate-bound trace metals with particular emphasis on the regions around estuarine plumes. 8. To measure the concentrations and sizes of natural particulate material using in situ sizing techniques and to compare the results obtained to those from conventional techniques. 9. To determine the numbers of cyanobacteria in the North Sea and to measure their rates of photosynthesis and various physiological/ecological properties. 10. To deploy the IMER offshore mesocosm and to conduct time series experiments of 2-3 days duration in relation to enrichment of the water column by plant nutrients. 11. To investigate, in detail at one site, aspects of denitrification. 12. To conduct investigations on the populations, physiology, size and trophic structure of natural populations of plankton and using shipboard flow cytometry. |
| Chief scientist | Nicholas J P Owens (Institute of Marine Environmental Research, Plymouth) |
| Cruise report |  (0.73 MB) |
| Ocean/sea areas | |
| General | North Sea |
| Specific | North Sea |
| Track charts | (0.04 MB) |
| Measurements | |
| Physical oceanography | |
| Surface measurements underway (T,S) | Quantity: track kilometres = 3557 |
| Water bottle stations | Quantity: number of stations = 35 Description: S surface only |
| CTD stations | Quantity: number of stations = 74 |
| Subsurface temperature and salinity measurements | Quantity: track kilometres = 3557 |
| Optics (eg underwater light levels) | Quantity: track kilometres = 3557.692 |
| Chemical oceanography | |
| Other dissolved gases | Quantity: track kilometres = 3557 |
| Phosphate | Quantity: track kilometres = 4444.8 Description: continuous observations throughout the cruise. |
| Nitrate | Quantity: track kilometres = 4444.8 Description: continuous observations throughout the cruise. |
| Nitrite | Quantity: track kilometres = 4444.8 Description: continuous observations throughout the cruise. |
| Silicate | Quantity: track kilometres = 4444.8 Description: continuous observations throughout the cruise. |
| Biology and fisheries | |
| Primary productivity | Quantity: number of experiments = 74 |
| Phytoplankton pigs (eg chlorophyll, fluorescence) | Quantity: number of profiles = 74 |
| Particulate organic matter (inc POC, PON) | Quantity: number of profiles = 74 |
| Phytoplankton | Quantity: number of profiles = 74 Description: survey distribution, biomass determination and energy transfers. |
| Geology and geophysics | |
| Core - soft bottom | Quantity: number of cores = 8 Description: chemical analysis |
