No abstract

Appendicularians are one of the most common animals found within zooplankton assemblages. They play a very important role as filter feeders but are, unfortunately, inconsistently reported in the Antarctic literature. The present paper attempts to describe the zonal diversity of appendicularians and the main environmental factors influencing their communities in the Drake Passage. Samples were collected during Antarctic summer in 2009–2010. A total of eight species of larvaceans were identified. Fritillaria borealis was the species found in the highest numbers in almost the entire studied area, and was observed at all sampling stations. The distributions of other taxa were limited to specific hydrological zones and hydrological conditions. F. fraudax and Oikopleura gaussica were typical of the areas between the Polar Front and the Subantarctic Front zones, and their distributions were significantly correlated with temperature and salinity, likely making them good indicator species. The F. fusiformis distribution was strictly related to South American waters. In summary, temperature was the strongest environmental factor influencing the larvacean community structure in the Drake Passage, and we also found that testing environmental factors on larvaceans as a whole group did not give entirely reliable results.

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The aim of this study was to describe the production biomass and abundance dynamics of the major Baltic calanoid copepods

The main objective of this paper was description of seasonal and interannual trends in secondary production and mortality rates of the three most important Copepoda taxa in the Gulf of Gdańsk (southern Baltic Sea). Samples were collected monthly from 6 stations located in the western part of the Gulf of Gdańsk during three research periods: 1998-2000, 2006-2007 and 2010-2012. Production was computed basing on copepod biomass and mortality rates estimated according to vertical life table approach. Redundancy analysis was used to investigate relationship between secondary production and environmental conditions. Considering the entire research period there was significant interannual and seasonal variability of secondary production, mortality rate as well as abundance and biomass anomalies. Conducted analysis revealed correlation between increasing temperature and production of Acartia spp. and T.longicornis developmental stages, while older copepodites of P.acuspes showed almost negative correlation with temperature. The mortality rate estimations obtained for Acartia spp. Were highest in summer, while for T.longicornis peak was usually noted in spring-summer period. Lowest mortality rate estimations were noted in autumn and winter for almost all stages of investigated taxa.