Spatial measurements
Plankton sampling by the CPR survey
The Continuous Plankton Recorder (CPR) programme has been making repeated measurements of the abundance and distribution of phytoplankton and zooplankton in the North Atlantic for more than 50 years. On some routes of the network monthly sampling is unbroken since 1946. Measurements of plankton are taken from Ships of Opportunity (SOOP’s) using a towed body. Water passes through a silk mesh that moves past an aperture at the front of the CPR and the plankton retained on the silk are analysed in the laboratory. Identification of up to 500 different phytoplankton and zooplankton taxa is possible together with an estimate of phytoplankton biomass based upon discoloration of the silk (phytoplankton colour index). Direct comparisons between the phytoplankton colour index and other phytoplankton chlorophyll estimates including SeaWiFS satellite derived estimates show strong positive correlations.
Ferrybox
FerryBox provide a practical approach to the establishment of cost effective monitoring systems using the principle established by the CPR of employing SOOP’s to carry sets of scientific instruments (Boxes). There are a number of operational routes in the North Sea including, for example, GKSS Harwich to Cuxhaven and the NIOZ Den Helder to Texel. Payloads vary depending on the primary purpose of the specific programme. The GKSS FerryBox is an automatic system comprised of instruments that measure variables including temperature, salinity, oxygen, nutrients (nitrogen, phosphate, silicate), chlorophyll fluorescence and turbidity. All sensors are installed in a continuous flow system. Water from the sea is pumped through this system during sailing of the ferry from a depth of 5 m. The ferry followsFebruary 28, 2006 data set each day that resolves short-term events that are unlikely to be sampled using traditional shipboard measurements from research vessels. The NIOZ FerryBox programme includes measurements of surface salinity, temperature and turbidity together with a downwards facing ADCP recording the current field below the ferry. The ferry crosses the transect across the Marsdiep tidal inlet each 30 minutes daily from 06.00 to 22.00 hrs, permitting resolution of tidal variability. The Cuxhaven – Harwich and Den Helder-Texel routes are part of an European project (www.ferrybox.org), which is coordinated by GKSS, with the goals to develop and establish a network of Ferry-Boxes in Europe for operational monitoring
Current SOOP sampling
Historical CPR sampling
Location of current CPR survey routes and also FerryBox routes and a composite figure showing the historic range of CPR samples in the North Sea
