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Influence of environmental factors on the population dynamics of key zooplankton species in the Gulf of Gdańsk (southern Baltic Sea)

Musialik-Koszarowska Maja, Dzierzbicka-Głowacka Lidia, Weydmann Agata

Oceanologia

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2019

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No. 61 (1)

17--25

EN

We studied the influence of abiotic environmental factors on the seasonal population dynamics' of Acartia spp., Temora longicornis and Pseudocalanus sp. in the southern Baltic Sea in the period of 2006-2007 and 2010-2012. Zooplankton samples were being collected monthly AT 6 stations located in the western part of the Gulf of Gdańsk with aWP2 net (100 μm mesh sizes) and then analyzed according to the HELCOM guidelines. Although the sampling stations did not significantly differ from each other in the terms of variability of abiotic environmental factors, the biomass of copepods developmental stages differed between them, apart from the shallow stations in both, Gulf of Gdańsk and in its inner part — Puck Bay. According to redundancy analysis, 26.1% of the total variability observed in the biomass of the copepod species has been explained by water temperature, salinity, air temperature, cloudiness, wind speed and direction and station's depth, with the first variable having the greatest power, alone explaining 13.7%. ANOSIM revealed that sampling stations in the Gulf of Gdańsk were significantly different from one another in terms of copepods' biomasses. Generalized Additive Models fitted for water temperature and salinity were significant for all ontogenetic stages of Acartia spp. and Temora longicornis and for the majority of stages of Pseudocalanus sp. (apart from the C1 for both and the males for salinity).

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Interannual variability in the population dynamics of the main mesozooplankton species in the Gulf of Gdańsk (southern Baltic Sea): Seasonal and spatial distribution

Dzierzbicka-Głowacka L., Kalarus M., Żmijewska M. I.

Oceanologia

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2013

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No. 55 (2)

409-434

EN

The paper characterizes the population dynamics of the major Baltic calanoid copepod species (Acartia spp., Temora longicornis and Pseudocalanus sp.) in the Gulf of Gdańsk (southern Baltic Sea) from January 2006 to December 2007. The data were collected at six stations (M2, S1, S2, S3, S4, J23) located in the western part of the Gulf of Gdańsk. The objective of this research was to describe and compare the seasonal and spatial distributions of these three major copepod species. Their distributions in the study area are largely similar, although there are some exceptions regarding Pseudocalanus sp. Copepoda development in the Gulf was at its most intense from May to September, peaking in July. The abundance of these species was the least at the shallowest stations. Based on these results, the weighted mean depth WMD per developmental stage was calculated for Pseudocalanus sp., Acartia spp. and T. longicornis. The paper also compares the abundance (in indiv. m-2) of the copepodite stages of these species in two regions of the Baltic Sea (the Gulf of Gdańsk and the Gotland Basin). Except for Pseudocalanus sp., the abundance of these copepodite stages (ΣCII-CVI) in the Gulf of Gdańsk in 2006 was similar to that in the Gotland Basin in the mid-1990s; in spring/summer 2007, however, their abundances were significantly higher (ca 2-4 times) in the former region.

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Parameterisation of a population model for Acartia spp. in the southern Baltic Sea. Part 2. Egg production

Dzierzbicka-Głowacka L., Lemieszek A., Żmijewska M.I.

Oceanologia

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2009

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No. 51 (2)

185-201

EN

The paper describes the modelling of egg production in Acartia spp. under changing environmental conditions in the southern Baltic Sea (Gdańsk Deep). The hypothesis (Sekiguchi et al. 1980) that the food-saturated rate of egg matter production is equivalent to specific growth rate of copepods is applied. The average number of eggs produced per day by one Acartia female is obtained as a function of growth rate, i.e. by multiplying exp gN3-1 from the growth rate of the nauplius stage equation by Wfemale / Wegg. The copepod model, reduced to a zero-dimensional population model calibrated for Acartia spp. under the environmental conditions typical of the southern Baltic Sea, was used to determine the effects of temperature and food concentration on the growth rate of each of the model stages (see Part 1 - Dzierzbicka-Głowacka et al. 2009 - this issue). In this part, egg production as a function of the above parameters is evaluated. The rate of reproduction during the seasons in the upper layer of the Gdańsk Deep is also determined.

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Parameterisation of a population model for Acartia spp. in the southern Baltic Sea. Part 1. Development time

Dzierzbicka-Głowacka L., Lemieszek A., Żmijewska M.I.

Oceanologia

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2009

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No. 51 (2)

165-184

EN

The copepod model (see Dzierzbicka-Głowacka 2005b), reduced to a zero-dimensional population model (Fennel 2001, Stegert et al. 2007), is calibrated for Acartia spp. under the environmental conditions typical of the southern Baltic Sea. Most of the coefficients used in the model are taken from the literature, containing values from various published studies and parameters derived for similar species. The parameters for growth are presented in Part 1; those for population dynamics are given in Part 2. Ingestion rates, which are dependent on developmental stage, food supply, temperature and weight of the animals, are estimated for Acartia bifilosa at 15°C from the Gdańsk Deep after the experimental data of Ciszewski & Witek (1977). In Part 1 the model presents the change in mean individual mass in successive stages. Quantitative formulae are obtained describing the effects of temperature and food concentration on the development time of Acartia spp. for each of the model stage groups. The generation time during the seasons in the upper layer of the Gdańsk Deep is also determined. The simulations computed here are similar to the experimental results. Part 2 (Dzierzbicka-Głowacka et al. 2009 - this issue) will evaluate egg production as a function of the above-mentioned parameters, temperature and food availability.