Time-series of total mesozooplankton, main groups and copepod taxa from eLTER-IT15-001-M, Promontory of Portofino – Ligurian Sea (2003-2015)

The dataset contains abundance data (ind. m-3) of total mesozooplankton, main groups and copepod taxa from the Punta Faro station (44° 17.750’ N, 9° 13.050’ E) in the Long-Term Ecological Research site eLTER-IT15-001-M, Promontory of Portofino – Ligurian Sea, over the years 2003-2015. Zooplankton samples were collected in the upper 50 m of the water column by vertical tows of a WP2 net (200-µm mesh, 57-cm mouth diameter) and fixed with buffered 4% formaldehyde. In the laboratory, the samples were concentrated and resuspended in filtered seawater to a volume of 500 ml to remove the formaldehyde. Aliquots ranging from 1/4 to 1/16, depending on sample density, were taken using a Folsom plankton sample splitter, transferred to a gridded Petri dish and examined under a stereomicroscope, and all the non-copepod zooplankton taxa were identified and counted. For copepods, an aliquot was taken with a large glass pipette from the 500 ml resuspended sample, transferred to a mini-Petri dish and individuals were counted; subsequent aliquots were added until at least 100 copepods were counted. 

The level of taxonomic consistency has generally been consistent over the years. Identification to genus or species level has been consistent only for copepods and cladocerans, while all other zooplankton taxa were identified as broader taxonomic groups. Taxa that were inconsistently recorded were homogenized to a higher taxonomic level to ensure data consistency over the entire time-series. The taxon abundances reported here correspond to the whole population (adult females and males, and juveniles). 

Groups in the dataset are defined as follows: Appendicularia (Fritillaria spp. + Oikopleura spp.)Chaetognatha (Sagittidae)Thaliacea (Salpidae + Doliolidae)Meroplankton (larvae of Mollusca, Bryozoa, Cirripedia, Echinodermata, Malacostraca, Nemertina, Polychaeta, Pisces larvae and eggs, Undetermined eggs)Offshore copepods (Aetideidae, Calanidae, Candaciidae, Euchaetidae, Eucalanidae, Heterorhabdidae, Lucicutiidae, Pleuromamma spp., Scolecitrichidae)Neritic copepods (rare Acartiidae, rare Centropagidae, Isias clavipes, Ctenocalanus vanus, Paracalanus denudatus, Paracalanus nanus, Corycaeus spp., Euterpina acutifrons)