Cinzia Brugnano

Zooplankton responses to hydrological and trophic variability in a Mediterranean coastal ecosystem (Lesina Lagoon, South Adriatic Sea)

Spatial and temporal variability in zooplankton was studied at eight stations located in the Lesina Lagoon (South Adriatic Sea) Salinity, temperature, dissolved oxygen and chlorophyll a (in the lagoon) at these stations were also assessed. The zooplankton community was characterised by clear seasonal oscillations and mostly represented by copepods and their larvae. The dominant copepod species were Calanipeda aquaedulcis and Acartia tonsa, which exhibited spatial–temporal segregation in the lagoon. C. aquaedulcis copepodites seemed to be better adapted to oligotrophic and oligohaline conditions compared with the A. tonsa population. The invasive species A. tonsa has completely replaced the formerly abundant Acartia margalefi. A positive correlation was found between abundances, total species numbers and trophic state. An increasing abundance trend was shown from the lagoon towards the sea. The highest diversity indices were recorded at the two channel inlets, during high tide due to the absence of a clear dominance of one or more coastal species and the co-occurrence of species of lagoon and marine origin.

Preliminary data on egg production rates of Pseudocyclops xiphophorus Wells, 1967 from the brackish lake Faro (north-eastern Sicily)

Field and laboratory studies were carried out on the bentho-planktonic species P. xiphophorus Wells, 1967. This species was found in the Mediterranean Sea, in the brackish Lake Faro (north-eastern Sicily) for the first time. Specimens of P. xiphophorus were collected from November 2003 to September 2004. Immediately after sampling, all adult females were sorted and pipetted individually into 50 ml crystallizing dishes containing lake water and incubated at the same enviromental temperature, measured at the sampling time. After 24 h, the number of eggs produced by each female was counted to estimate in situ egg production rate. In the laboratory, groups of five couples of males and females were placed individually into 50 ml crystallizing dishes containing filtered sea water enriched with three phytoplankton species, Tetraselmis suecica, Pavlova lutheri, and Isochrysis galbana, given in excess concentrations. Groups of five replicates were incubated at three different temperatures, 16, 24, and 28 °C, for each replicate. Every couple was monitored daily during the entire life cycle to estimate egg production rate in relation to temperatures. In the laboratory, mean egg production rates per female per day for each group of couples exhibited a positive correlation with temperature that was recorded in in situ experiments as well.

Food type effects on reproduction of hyperbenthic calanoid species Pseudocyclops xiphophorus Wells, 1967, under laboratory conditions

Egg production, hatching success and naupliar survival were determined for Pseudocyclops xiphophorus pairs fed a Skeletonema marinoi, a flagellate (Tetraselmis suecica, Pavlova lutheri and Isochrysis galbana) and a mixed (Skeletonema and flagellates) diet. Pairs fed Skeletonema marinoi showed significantly lower egg production and naupliar survival than couples fed flagellates and mixed diet. But hatching success was more or less similar with the three food types. Furthermore, feeding experiments demonstrated a clear preference of P. xiphophorus for the flagellate food type.

Spring and autumn spatial distribution of zooplankton carbon requirement across the Mediterranean Sea

ABSTRACT Zooplankton represents a key contributor to the ocean biological pump through its consumption of sinking and suspended carbon. A specific and highly sensitive method to evaluate zooplankton carbon requirement from the sinking flux is through the estimation of the activity of the electron transport system. The present study was carried out from samplings in 2006, and it was focused on the spatial 200–0 m zooplankton carbon demand across 24 sampling stations, along the Mediterranean Sea, from the island of Crete to the Strait of Gibraltar. Its potential day/night variability was evaluated. The zooplankton composition, abundance and biomass were investigated. The carbon demand per unit zooplankton biomass indicates geographical and diel differences among the sampling stations. A higher mean carbon demand was seen for the western Mediterranean with respect to the eastern Mediterranean, which can be justified through the observed ratio of gelatinous:crustacean taxa and the water temperatures recorded. Higher carbon demand was measured in samples collected during the dark hours. The relation to the presence and abundance of actively migrating euphausiids and copepods was discussed. A comparison with data from another of our study carried out in the same study area but in another seasonal period was done.

Two new species of asterocherid (Copepoda: Siphonostomatoida) associated with a sponge from the Strait of Messina, Italy: taxonomic and ecological traits

Two new species of asterocherid associated with sponges are described from the Mediterranean Sea. They are Psilomyzon laetitiae sp. nov. and Psilomyzon sarcotragusicola sp. nov. The genus Psilomyzon consists of only one known species, P. pauciseta. The two new species can be easily distinguished from the cogener species by reduction of the endopod of leg 4. In P. pauciseta the leg 4 endopod is 3-segmented, with the third segment reduced; in both new species it is 2-segmented, with the second segment carrying an inner projection, possibly homologous to the third segment of the leg 4 endopod of P. pauciseta. In the two new species, the bifid outer process on male leg 4 second endopodal segment seems to be serially homologous to the similar processes on the same segment in legs 1–3, whereas the inner projection may represent a vestigial element of the third endopodal segment of leg 4. http://zoobank.org/urn:lsid:zoobank.org:pub:33BF0653-BBA9-426B-B365-5D8C62DFD44A