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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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Modeling of egg production by Temora longicornis from the southern Baltic Sea including salinity

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

Oceanological and Hydrobiological Studies

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2013

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Vol. 42, No. 3

277--288

EN

The paper presents modeling of egg production (Egg — no. of eggs female−1 d−1) by Temora longicornis in the changing environmental conditions of the southern Baltic Sea (Gdańsk Deep). It is hypothesized that the food-saturated rate of egg matter production is equivalent to the specific growth rate of copepods. Based on the findings from the south-western Baltic Sea, Egg of T. longicornis is evaluated as a function of food concentration, temperature and salinity over a wide range of these parameters. Subsequently, the rate of reproduction during the seasons in the Gulf of Gdańsk is determined. According to our calculations, values of Egg reach ca 11 eggs per day in April and decline strongly in June-July, while the second smaller peak in reproduction occurs in September, ca 8 eggs per day. Our results suggest that egg production rates of T. longicornis depend not only on food concentration and temperature, but also on salinity, which is a masking factor in the Baltic Sea.

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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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Development and growth of Temora longicornis: numerical simulations using laboratory culture data

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

Oceanologia

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2011

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No. 53 (1)

137-161

EN

Quantitative expressions are presented to describe the effects of temperature and food concentration on stage duration and growth rate of Temora longicornis for each of the model stage groups (N1-N6 - naupliar stages, C1, C2, C3, C4, C5 - the five copepodid stages). The calculations were made on the basis of experimental data from the literature for Temora longicornis from the south-eastern and the southern North Sea. Relationships were obtained between the growth parameters and temperature for the 5-10°C temperature range and food concentrations from 25 mgC m-3 to excess. Also computed was the total mean development time as a function of the above-mentioned parameters, temperature and food availability. The simulations computed here are similar to the experimental results. The growth rates for successive stages were obtained according to the correction of the "Moult Rate" method, which allows the use of mean weights and stage durations. The calculations also suggest that three complete generations of T. longicornis from the Gdańsk Deep (the southern Baltic Sea) can develop during a single year.