School of Engineering and Science - Jacobs University

CHAPTER III
Net growth of plankton in the mesocosms
Phytoplankton and microzooplankton net growth rates in the mesocosms were
calculated using the exponential growth model and the abundance values from the
monitoring (see section ‘Growth and grazing calculations’).
Grazing experiments
Dilution experiments on microzooplankton grazing (Landry & Hassett, 1982, Landry,
1993) and bottle incubations with the copepod Temora longicornis were carried out
simultaneously at four different times (see introduction) of the phytoplankton bloom
(Figure 1).
Figure 1: Development of phytoplankton and microzooplankton biomass during the mesocosm
experiment. Dates at which the grazing experiments were performed are marked with arrow. Error bars
correspond to one standard deviation (n = 3).
Microzooplankton grazing set up
A pool of water for the purpose of dilution was established at the same time as the
mesocosms were filled. Water was filtered at low pressure through a pre-washed 0.45 +
0.2 µm sterile in-line membrane filter capsule (Sartobran® 300, 300 cm²) after pre-
66