Proteomic measurement
Proteomic profiles were determined for all 752 specimens. For small copepods (< 2 mm) the whole specimen, for larger copepods (such as Calanus spp., Metridia sp., Paraeuchaetaspp.) a piece of the cephalosome was shortly dried at room temperature and kept in an Eppendorf tube. Depending on sample size 5-10 µl matrix solution (α-Cyano-4-hydroxycinnamic acid as saturated solution in 50% acetonitrile, 47.5% LC-MS grade water, and 2.5% trifluoroacetic acid) was added. After at least 10 min extraction, 1.2 µl of each sample was added onto the target plate, with 2-3 replicates. Protein mass spectra were measured from 2 to 20 kDa using a linear-mode MALDI-TOF System (Microflex LT/SH, Bruker Daltonics). Peak intensities were analyzed during random measurement in the range between 2 and 20 kDa using a centroid peak detection algorithm, a signal to noise threshold of 2 and a minimum intensity threshold of 400 with a peak resolution higher than 400 for mass spectra evaluation. Proteins/Oligonucleotide method was employed for fuzzy control with a maximal resolution 10 times above the threshold. For each sample 240 satisfactory shots were summed up.