Chlorophyll, net oxygen production and respiration rates measured on water bottle samples at List Intitute Beach, 1994-2007

For the determination of primary production surface water samples are filled into Winkler bottles. The sampling station is located directly in front of the institute. Samples are taken at least 3 hours before high tide (high tide should be around midday). In part of the samples the oxygen content is measured immediately (with a WTW-Multilab Pilot probe for oxygen and pH). The remainder of the samples is divided into two groups: 1. light incubation (to measure production), 2. dark incubation (o-value/respiration). The dark incubation bottles are wrapped in aluminium foil to shut out all light. At the sampling site the the samples are suspended from a rope (height above the bottom about 40 cm) for at least 6 hours. Afterwards the oxygen content, and lately also the pH, of both light and dark bottles is measured. […]