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1

Annual, seasonal and spatial differences in the growth rate of Baltic cod larvae and early juveniles in relation to zooplankton biomass fluctuations in 2006-2014

Spich Katarzyna, Fey Dariusz Piotr

Oceanological and Hydrobiological Studies

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2023

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Vol. 52, No. 4

399--419

EN

It is an acknowledged theory that a faster growth rate, determined by various environmental drivers, may boost the survival of larval and juvenile fish. In this study we examined the differences in the growth rate of larval and juvenile cod (age 2 – 136 d; SL: 4.1 – 39.2 mm) between the years 2006 and 2014, sub-areas of the Baltic Sea (Bornholm Basin, BB; Słupsk Furrow, SF; Gdansk Basin, GB), and seasons (spring and summer). The average growth rate for all specimens was 0.25 mm/d, with significantly lower values between 2012 and 2014 than between 2006 and 2011. A reduction in zooplankton biomass, especially the large zooplankton fraction, was observed after the 2006–2008 period, which was related to the prevailing temperature conditions in the surface layers. The reduction in zooplankton biomass was accompanied by changes in the structure of zooplankton: less T. longicornis, C. hamatus, and Pseudocalanus spp., and more Acartia spp. The results suggest that the inter-annual differences observed in zooplankton biomass and structure are likely responsible for the observed reduction in the growth rate of cod larvae between 2012 and 2014 compared to the years between 2006 and 2011. The growth rate reduction could be one of the reasons for the decline in the recruitment of eastern Baltic cod between the years 2013 and 2015, after the high recruitment years of the period 2011-2012.

2

First survey of metallic distribution in zooplankton from a south Moroccan area

Bouthir Fatima Zohra, Afandi Imane, Talba Sophia, Labonne Maylis, Masski Hicham, Waeles Mathieu, Lae Raymond

Oceanologia

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2023

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Vol. 65 (4)

612--623

EN

The Moroccan Southern Atlantic coast is mainly influenced by upwelling, Saharan dust and anthropogenic micropollutant input. These factors contribute to increasing the availability of metal elements in waters. To differentiate human impact from natural variability, knowledge of background concentrations of metals and their fluctuations in bioindicator organisms such as zooplankton is important. This work aims to determine the levels of metals elements (Zn, Mn, Pb, Cu, Cd, Cr, Co, Ni, Li, As, Sr, U, Fe and Ba) in zooplankton along the southern area of the Atlantic coast of Morocco. Zooplankton samples were collected in the summer (July 2013) and autumn (December 2013) at 27 stations from Sidi Ifni to the south of Dakhla. All stations were located on transects perpendicular to the coast. The analysis of metal elements in zooplankton was determined by ICP–MS. The results revealed that in all transects, metal concentrations were below the regulatory limits. Metal enrichments were observed in the south and decreased gradually to the north. This study can be used as baseline data for the metal contents of zooplankton in Moroccan South Atlantic coastal water. A comparison to worldwide reported data on zooplankton did not reveal any suggestions on increased metal presence in the area investigated.

3

Impact of Water Stress on the Planktonic Biodiversity of the Youssef Ben Tachafine Dam (Souss Massa, Morocco)

Boudarfa Fatima, Gallouli El Mahjoub, El Hafa Mohamed, Aamiri Ahmed, Oulad Ali Hassan

Ecological Engineering & Environmental Technology

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2023

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Vol. 24, iss. 8

97--106

EN

Drought is a large-scale disturbance that affects freshwater ecosystems worldwide. This recurrent phenomenon in Morocco, has experienced severe episodes during the last decade and has caused water stress in several aquatic ecosystems including the Youssef Ben Tachafine dam. Indeed, the volume of this reservoir has experienced its lowest historical hydrological level (12%) during the study period. To study the effects of water stress on water quality and planktonic community structure, water samples were collected from January 2019 to December 2020 at nine depths. The physicochemical parameters of the water were measured in parallel with the qualitative and quantitative study of the phytoplankton and zooplankton communities. The results obtained show a low planktonic diversity with only 43 phytoplanktonic species and 27 zooplanktonic species. The phytoplankton showed an almost permanent predominance of Chlorophyceae (85%), dominated by Closterium pronum, followed by Diatomophyceae (9.5%), dominated by Cyclotella ocellata. Rotifers represent the most abundant zooplanktonic group during the study period with two dominant species (Keratella tecta and Polyarthra vulgaris). Statistical analysis of the data from this study, using R software, revealed a negative correlation between Cladoceran species, Copepods and the diatom Cyclotella ocellata on the one hand and the decrease in water level, temperature and enrichment of the environment in nutrients and phytoplanktonic biomass on the other. This study shows that the effect of the extreme drought, which the Youssef Ben Tachafine dam has experienced, has altered the diversity and structure of planktonic communities, which threatens the sustainability of ecological services of this ecosystem.

4

Correlation Between Surface Water Quality and Plankton Composition in Water Bodies in Hau Giang Province, Vietnam

Quang Truong Chi, Giao Nguyen Thanh

Ecological Engineering & Environmental Technology

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2023

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Vol. 24, iss. 4

1--14

EN

The study was carried out to assess surface water quality in water bodies in Hau Giang province, Vietnam using individual surface water quality parameters and water quality index. In addition, the correlation of phytoplankton and zooplankton composition with surface water quality was also examined. The results showed that surface water quality in Hau Giang province was contaminated with organic matters, nutrients, iron and microorganisms. The water quality index (WQI= 37-84) showed that surface water ranged from moderate to good. A total of 164 species belonging to five phyla of phytoplankton were recorded with the density from 370–2260 individuals/L and 91 species belonging to five phyla of zooplankton with a density of 11,332–121,600 individuals/L. The predominance of the phytoplankton species Oscillaroria, Euglena, Phacus and the predominance of zooplankton species of the Nauplius, Rotifera and Protozoa signalize an aquatic environment rich in organic matters and nutrients. The correlation results showed that BOD, COD, NH4+-N, NO3--N and PO43--P were closely related to the density of phytoplankton while pH, DO, BOD, NH4+-N and coliform play an important role in determining the density of zooplankton species.

5

Summer distribution and community structure of surface water mesozooplankton from the eastern Mediterranean Sea

Isinibilir Melek, Aker Vedat, Türkeri Ezgi E.

Oceanological and Hydrobiological Studies

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2022

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Vol. 51, No. 4

308--324

EN

The zooplankton community structure and its relationship with environmental parameters were evaluated in the surface waters (0–50 m) of the eastern Mediterranean (the Aegean Sea’s coastal waters and the Levanine Sea’s coastal and offshore waters), from coastal waters to open sea waters, during the summer for two years. A total of 157 species/groups were registered in the study area. Copepods, cladocerans, doliolids, meroplankton and appendicularians represented the most important zooplankton groups. Five copepod species (Corycaeus [Onychocorycaeus] ovalis, Goniopsyllus clausi, Oncaea scottodicarloi, Sapphirina bicuspidata and Scaphocalanus curtus) have been recorded for the first time in Turkish coastal regions; three species (Centropages bradyi, Goniopsyllus clausi and Oncaea scottodicarloi) had not previously been found in the Aegean Sea; and one species (Goniopsyllus clausi) has been added for the first time to the eastern Mediterranean fauna. Moreover, Pleopis schmackeri was already found to be present in both the Aegean Sea and Mediterranean coasts of Turkey in August 2006. Dominant species varied from the coastal waters to open waters. A small number of species belonging to the coastal community (e.g. Penilia avirostris, Pseudevadne tergestina, Oithona plumifera, Paracalanus parvus and Centropages kroyeri) dominated all coastal areas. In contrast, the open water stations were characterised by the presence of typically epipelagic species of the Mediterranean Sea (e.g. Calocalanus spp., Clausocalanus furcatus, Lucicutia flavicornis, Mecynocera clausi, Farranula rostrata, Oncaea scottodicarloi and Oncaea mediterranea).

6

Asterionellopsis glacialis (Family: Fragilariaceae, Class: Bacillariophyceae, Phylum: Ochrophyta) bloom and its impact on plankton dynamics at Kalpakkam (Bay of Bengal, Southeast coast of India)

Sahu Gouri, Mohanty Ajit Kumar, Sarangi Ranjit Kumar, Satpathy Kamala Kanta

Oceanologia

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2022

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No. 64 (1)

145--149

EN

An intense bloom of Asterionellopsis glacialis (Family: Flagilariaceae; Class: Bacillariophyceae; Phylum: Ochrophyta) was observed in the near-shore waters at Kalpakkam, Tamil Nadu. Proliferation was supported by the favorable temperature, salinity, and nutrient levels in the coastal waters prevailing in the post-northeast monsoon period. BIOENV analysis and PCA confirmed salinity and nitrate as the key environmental factors responsible for the A. glacialis abundance. Cluster analysis further supported the distinct state of coastal water during the bloom with respect to physicochemical properties. The bloom period was floristically and faunistically richer than the pre- and post-bloom periods. The cluster and nMDS analysis confirmed the effects of bloom on plankton dynamics in the near-shore waters at Kalpakkam. The dominance of meroplankters especially, Cirripedia nauplii and Bivalvia larvae over Copepoda during the peak bloom period, was a significant result of the study. PCA ordination plot for the quantitative aspects of phytoplankton and zooplankton groups further supported the above observation. Among Copepoda, Cyclopoida and Poecilostomatoida (mostly carnivorous) exceeded the Calanoida (mostly herbivorous) during the peak bloom period unlike the reverse trend observed during other periods. Fish eggs and larvae were available in substantial numbers during the bloom which indicated their proliferation in the presence of the blooming diatom standing stock as the food material.

7

Spatial Distribution and Diversity of Marine Zooplankton Adjacent to the St. Martin's Island, Bangladesh

Alam Md. Jobaer, Kamal A. S. M. Maksud, Ahmed Md. Kawser, Khondker Moniruzzaman, Fayyaz Rafid

Journal of Ecological Engineering

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2022

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Vol. 23, nr 10

154--163

EN

Bangladesh, a country that lies on the north shores of the Bay of Bengal, has been blessed with a plethora of natural resources. St. Martin’s Island, the only coral-bearing island in Bangladesh, is undoubtedly regarded as one of the most prized possessions. It is rich in biodiversity, but truly scientific information on it is lacking. In the present investigation, 14 stations adjacent to St. Martin’s Island within the Bay of Bengal were sampled for determining the composition, spatial distribution, species richness, and diversity of pelagic zooplankton. Samples were collected in the pre-monsoon hot season. From the community of zooplankton, 34 species were reported. Most of the species belonged to copepods. Besides, Polychaeta and Cirripedia were also present in the community. The most significant species belonged to Oithona, Canthocalanus, Balanus, Euterpina, and Microsetella. Total zooplankton standing crop varied from 45,000–125,000 ind/m3 and the highest number of species (8) were observed at station 7. Strong variability in the distribution of species was observed in the studied stations. The number of genera collected at each station varied from 4–8. Data on species richness (Df) varied from 1.30–3.04 and that of the Shannon-Wiener Index (H) from 1.33–1.93. The species composition of zooplankton and the species richness and the diversity index of the population was comparable to the other studies carried out in the Central and Western Bay of Bengal.

8

Impact of heavy metals on the food web in the Mediterranean lagoon, Lake Burullus, Egypt

Hegab Mahmoud H., Ahmed Nasr M, Kadry Shadia M., ElSayed Radwa A., Goher Mohamed E.

Oceanological and Hydrobiological Studies

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2020

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Vol. 49, No. 3

215--229

EN

Research on the impact of heavy metals and their accumulation in ecosystem elements of Lake Burullus is still scarce. Therefore, this study focuses on the relationship between the levels of heavy metals in the lake water, plankton communities and Nile tilapia (Oreochromis niloticus). The mean annual concentrations of Fe, Zn, Cu, Mn, Pb and Cd in water and fish samples were 527.8, 366.7, 162.6, 137.3, 119.8 and 3.6 μg l−1, and 70.8, 43.6, 8.05, 1.2, 0.14 and 0.045 μg g−1 dry weight (d.w.), respectively. The study demonstrated the relationship between the accumulation of metals in fish muscles and their levels in the lake water (p < 0.05; r = 0.7–0.9), with the metal content in O. niloticus muscles being mostly below the permissible limits. The obtained results showed that the levels of the metals in the lake water are not correlated with phytoplankton and zooplankton, and their groups, except copper and zinc, are negatively correlated with phytoplankton (r = −0.45 and −0.58, respectively). The study concluded that the concentrations of the analyzed metals in Lake Burullus did not reach the effective levels that would have a significant impact on the distribution of phytoplankton and zooplankton, or a hazardous effect on O. niloticus and its safety for human consumption.

9

Unravelling the spatio-temporal variation of zooplankton community from the river Matla in the Sundarbans Estuarine System, India

Nandy Tanmoy, Mandal Sumit

Oceanologia

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2020

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No. 62 (3)

326--346

EN

Zooplankton is an important bioindicator of ecosystem functioning. Knowledge of the seasonal fluctuation in the zooplankton population in estuarine waters of the Indian Sundarbans is rather limited. In the present study, we analysed the community structure of zooplankton assemblages and their spatio-temporal variations based on different multivariate statistics and indicator value analysis. A total of 56 taxa were identified and the density was primarily dominated by planktonic copepods and few meroplankton communities during four sampling seasons. The most abundant species were: Acartia spinicauda, Acartia sp., Bestiolina similis, Euterpina acutifrons, Labidocera acuta, Paracalanus aculeatus, Paracalanus parvus and Paracalanus indicus. Canonical Correspondence Analysis highlighted that temperature, pH, DO, salinity and nutrients were the prevailing environmental parameters associated with significant spatio-temporal changes of zooplankton distribution in this area. The highest abundance of zooplankton was recorded in winter, followed by monsoon, summer and spring. Throughout the study period, different zooplankton indices were observed in good condition. Seasonal occurrence of dominant zooplankton with high IndVal index was markedly observed and it might be used as a potential bioindicator for a particular season and environmental condition in this estuarine complex. The results of this study provide evidence for the presence of warm water species in the estuarine waters of the Indian Sundarbans and can be a clear indication of climate change-mediated elevated temperature in the estuarine system. Our results underscore the high diversity of zooplankton from mangrove dominated estuarine complex and emphasize the need for long-term monitoring in ecologically fragile ecosystems like the Sundarbans Estuarine System.

10

Short-term variation of zooplankton community in Cintra Bay (Northwest Africa)

Berraho Amina, Abdelouahab Hinde, Baibai Tarik, Charib Said, Larissi Jamila, Agouzouk Aziz, Makaoui Ahmed

Oceanologia

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2019

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No. 61 (3)

368--383

EN

This is the first study that describes the spatial-temporal distributions of the zooplank- ton community and potential control factors in Cintra Bay. Zooplankton were sampled using a bongo net, 150 μm mesh size, during two surveys, in autumn 2015 and spring 2016, extending from the coast to the open sea. Fourteen zooplankton groups were identified, where copepods represented 49.1% and 92.5% of the total abundance in autumn 2015 and spring 2016, respectively. Tintinnids accounted for 39.7% and 4.7%, respectively. The total zooplankton abundance was higher in autumn (55 992 ind m-3) than in spring (2123 ind m-3). Nineteen species of copepods, belonging to 14 families, were identified. Euterpina acutifrons and Oithona nana were the most common and abundant species. The Acartiids were represented by three species (Acartia clausi, A. tonsa and A. bifilosa) in autumn and one species in spring (A. clausi). The copepods diversity was significantly different between the two seasons showing high values at the entrance and the center of the bay in autumn 2015 and in the southern half of the bay in spring 2016. The copepod structure was characterized by 13 species at different degrees of contribution in autumn 2015. In spring 2016, only four species qualified as indicator species although their contribution was not significant. Given its large opening on the ocean, Cintra Bay benefits largely from the conditions of the oceanic environment, particularly the upwelling. This situation is likely to have an impact on the spatiotemporal variability of the composition and distribution of zooplankton, especially the copepods.

11

Life in sympatry : coexistence of native Eurytemora affinis and invasive Eurytemora carolleeae in the Gulf of Finland (Baltic Sea)

Sukhikh Natalia, Souissi Anissa, Souissi Sami, Holl Anne-Catherine, Schizas Nikolaos V., Alekseev Victor

Oceanologia

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2019

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No. 61 (2)

227--238

EN

The invasion of exotic species into native ecosystems is becoming a crucial issue in global biology. Over the last ten years, at least 45 invasions of aquatic species have been reported in the eastern part of the Gulf of Finland; the majority of them were introduced through ballast water. Recently, invasion of the estuarine calanoid copepod Eurytemora carolleeae (Temoridae), originating from North America, has been reported in several European estuaries and particularly in the Gulf of Finland. This species is morphologically very similar to the native Eurytemora affinis, but it is easily discriminated by molecular markers. In this study, we monitored the distribution area of the invasive copepod species in European waters, as well as the population structure of (native) E. affinis and (invasive) E. carolleeae, from 2006 to 2018 in the Gulf of Finland. The population density of E. affinis was significantly higher, compared to E. carolleeae, during most of the study period. The only exception was Neva Bay in 2010, wherein the invasive species dominated possibly due to high temperatures and differences in the levels of fish predation. The reproductive performance of E. carolleeae was also higher than that of E. affinis. These results show different population dynamics between the two species. It was revealed that invasive E. carolleeae develops in some of the very same habitats as native E. affinis, thereby potentially becoming a significant component of the zooplankton in the studied area. Moreover, invader has the potential to displace native E. affinis.

12

Is zooplankton an indicator of the water trophic level in dam reservoirs?

Pociecha A., Bielańska-Grajner I., Kuciel H., Wojtal A. Z.

Oceanological and Hydrobiological Studies

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2018

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Vol. 47, No. 3

28--295

EN

The trophic state of ten dam reservoirs was assessed using a zooplankton community. In order to determine the trophic state of dam reservoirs, we used indices calculated on the basis of density and species structure of Rotifera and Crustacea communities. Samples were collected once during summer 2012 in ten dam reservoirs. The largest numbers of zooplankton taxa were found in a lowland high meso-eutrophic dam reservoir (Koronowski) and the lowest ones in a submontane low eutrophic dam reservoir (Lubachowski). The trophic state was determined for the investigated dam reservoirs. In the case of the Rotifera community, the percentage of the tecta form in the Keratella cochlearis population and the proportion of high-trophic species in the total species density were the best indices to describe the water trophic status. In the case of the crustacean community, the best indices were the density of Crustacea and the biomass of Cyclopoida. The high value of all indices calculated on the basis of density and species structure of Rotifera and Crustacea was determined for Zygmunt August Lake, whose trophic status was defined as highly eutrophic to polytrophic. Our study has shown that zooplankton could be a good ecosystem indicator of the water trophic level in dam reservoirs.

13

Zooplankton structure in high latitude fjords with contrasting oceanography (Hornsund and Kongsfjorden, Spitsbergen)

Ormańczyk M. R., Głuchowska M., Olszewska A., Kwaśniewski S.

Oceanologia

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2017

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No. 59 (4)

508--524

EN

Zooplankton inhabiting the Hornsund and Kongsfjorden fjords on Spitsbergen (Svalbard) were investigated in summer 2013. The goal of the study was to determine how the zooplankton communities vary in environments functioning under different oceanographic regimes. Sampling was conducted with nets of different mesh size and selectivity (56 μm WP-2, 180 μm MultiNet, and 1000 μm Tucker Trawl), which permitted comparing a wide size spectrum of zooplankton components. Species composition did not differ substantially between the fjords, but the zooplankton in Hornsund was almost two times less numerous, and it had lower biomass per unit volume. The highest abundance at both sites was in the smallest zooplankton size fraction found only in samples taken with 56 μm mesh WP-2 net. These comprised as much as 71% and 58% of the total zooplankton abundance in Hornsund and Kongsfjorden, respectively. The communities in both fjords had comparable contributions of Arctic and boreo-Arctic species biomass in the year of the study. However, the comparison of zooplankton characteristics over several years showed changes in abundance and biogeographic structure that corresponded with variations in the physical environments of the fjords. The results of the study permit predicting the possible effects of the increasing influence of Atlantic waters on zooplankton communities inhabiting Arctic marine pelagic ecosystems.

14

Effect of physicochemical parameters on zooplankton in the brackish, coastal Vistula Lagoon

Paturej E., Gutkowska A., Koszałka J., Bowszys M.

Oceanologia

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2017

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No. 59 (1)

49--56

EN

This paper analyzes whether physicochemical properties significantly influence the occurrence of zooplankton in a brackish reservoir. The studies were carried out on the Vistula Lagoon in August and September from 2006 to 2009 at 32 research sites. The environmental conditions in the Vistula Lagoon varied widely. At the time of the investigation, 17 species of rotifers, six species of Cladocera, and ten species of Copepoda were noted, and the total density of plankton fauna ranged from 145 to 765 ind. dm−3. Statistical analysis demonstrated a significant correlation between the occurrence of some zooplankton species and certain environmental parameters, whereas the sampling sites were grouped according to study years. The zooplankton systems recorded at the research sites in 2006 constitute the most disparate group. Thus, it can be concluded that physicochemical properties might significantly impact both individual species (depending on their environmental demands) and entire zooplankton clusters.

15

Zooplankton structure in midfield ponds in north-west part of Poland

Brysiewicz A., Jankowski M., Tański A.

Infrastruktura i Ekologia Terenów Wiejskich

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2017

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nr IV/2

1673--1686

EN

Midfield ponds are characterised by a rich biodiversity. A significant role in the function of these specific water ecosystems is played by resident zooplankton, which is a valuable component of numerous trophic networks. The aim of the present work was to study the taxonomic composition, concentration and biomass of zooplankton in two midfield ponds situated in the area of one commune, but geomorphologically different from each other. Experiments were conducted in the summer seasons (June-August) in the years 2011-2013 in two ponds. The presence of 55 zooplankton taxa, commonly present in such water reservoirs in Poland, was observed. Most species were determined. The largest group comprised rotifers (Rotifera) - 35 taxa. The crustacean zooplankton was less diverse: 11 taxa of copepods (Copepoda) and 9 taxa of water fleas (Cladocera) were found. The reservoir in Stare Czarnowo exhibited a greater number of taxa, where as many as 40 taxa were observed. However, 35 taxa belonging to various zooplankton groups were found in the pond in Żelisławiec. The relatively low Jaccard index confirmed small qualitative similarity between the studied ponds. Both reservoirs contained representatives of species defined as characteristic for oligosaprobic and mesosaprobic waters, which may indicate small contamination of the two ponds and the occurrence of a large amount of organic matter undergoing decomposition.

16

Microcrustacean (Cladocera, Copepoda) source-sink dynamics in a lowland river ecosystem with a dam reservoir

Karpowicz M.

Oceanological and Hydrobiological Studies

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2016

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Vol. 45, No. 3

297--303

EN

Dispersal of crustacean zooplankton from a reservoir in a lowland river was observed over a relatively long distance. Zooplankton samples were collected by a unique technique from “the same water”. Large Cladocera (Daphnia cucullata and Diaphanosoma brachyurum) showed the greatest reduction in a river, but they were common over a distance of up to 130 km below a dam. These two planktonic species revealed a low potential for colonizing oxbow lakes. Eurytopic Chydorus sphaericus and Mesocyclops leuckarti transferred from the Siemianówka Reservoir had a great dispersal capacity in the Narew River and could effectively support local populations in oxbow lakes over a distance of 180 km. Similarity between the crustacean communities in the river and the reservoir significantly decreased with the increasing distance from the dam. At the same time, crustacean communities in oxbow lakes were not affected by the distance from the source. Dispersal from the large source of zooplankton to local communities is a very important process but the local environmental factors such as habitat heterogeneity, aquatic vegetation and the hydrological connectivity can be strong enough to affect the structure of local crustacean communities in oxbow lakes.

17

Scale-dependent environmental control of mesozooplankton community structure in three aquaculture subtropical bays of China

Sun D., Liu Z., Wang C.

Oceanologia

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2016

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No. 58 (2)

124--134

EN

Most subtropical bays of China have been under heavy pollution since the late 1990s, mainly because of the rapid development of aquaculture and discharge of industrial and agricultural wastewater. Some projects were conducted to investigate the zooplankton community in these bays, but those studies were less focused on the relationship between spatial structure of mesozooplankton community and environmental variables in/among bays. The mesozooplankton community structures in relation to physical, chemical and biological variables were studied in three subtropical bays of China with seasons and different spatial scales during 2000 and 2002–2003. Data were collected on temperature (T), salinity (S), concentration of chlorophyll a (Chl a), pH, dissolved oxygen (DO), soluble reactive phosphate (SRP), dissolved inorganic nitrogen (DIN), chemical oxygen demand (COD), suspended particle material (SPM) and mesozooplankton taxonomic abundances. Correlation analysis showed that the main environmental factors correlated to the total abundance of mesozooplankton in these subtropical bays were Chl a, temperature, COD and SRP. Multivariate analysis indicated that DO, Chl a and temperature were the principal factors in influencing spatial differentiation of zooplankton community structure in the inter-bay scale. At the within-bay scale, the influencing factors were different among bays; the main factors were physical variables for Xiangshan Bay and Sanmen Bay, while chemical variables for Yueqing Bay, respectively. The results revealed that the environmental variables that affected spatial structure of mesozooplankton community were different at inter-bay scale and within-bay scales, and zooplankton community was more influenced by chemical (e.g. nutrients/ammonia) variables when under serious eutrophication condition, while it would be more influenced by physical variables (temperature/salinity) when under less eutrophic conditions.

18

Cenotes – lakes of the Yucatan Peninsula (Mexico)

Szeroczyńska K., Zawisza E.

Studia Quaternaria

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2015

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Vol. 32, Nr 1

53--57

EN

Cenote lakes are natural sinkholes or depressions resulting from the collapse of limestone bedrock exposing the groundwater underneath. Thousands of such lakes are particularly encountered on the Yucatan Peninsula (Mexico). These lakes were of great significance for the Maya culture as important religious places and primary source of drinking water. They permitted the survival of Mayan communities through dry periods known as “Maya drought”. Most of the cenote lakes are large open water pools measuring tens of meters in diameter. The majority of cenotes are smaller sheltered sites. Their waters are usually very clear and oligotrophic, originating from rain water filtering slowly through the ground. The authors visited and collected zooplankton samples from eight cenotes in November 2013, namely: Ik-Kil, Samula, Zaci, X-Kekn, Actum Ha, Cristal, Sian Ka’an, and Chan Chemuxil (transect Merida–Tulum– Cancun). The analysed lakes differ considerably in morphological terms, varying from very deep to shallow. Some of them are under human impact (tourists). The water samples were analysed for zooplankton content, but the phytoplankton frequently occurring was also taken into account. The obtained results are largely varied, indicated big eco- logical verity among cenotes which depended on lake age, localization and morphometry. As showed our study Cladocera zooplankton was very rare and only present at several sites. Between the fauna community Copepoda and Ostracoda species were the most abundant. Phytoplankton were present in all studied lakes and it sees that played the central role in those ecosystems.

19

Potential effects of abiotic factors on the abundance and distribution of the plankton in the Western Harbour, south-eastern Mediterranean Sea, Egypt

Heneash A. M. M., Tadrose H. R. Z., Hussein M. M. A., Hamdona S. K., Abdel-Aziz N., Gharib S. M.

Oceanologia

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2015

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No. 57 (1)

61--70

EN

Samples were collected seasonally from Western Harbour during winter 2012–winter 2013 to examine spatial and temporal variability in phytoplankton and zooplankton abundance in relation to physicochemical parameters. Water was alkaline and well oxygenated. Nutrient concentrations were generally high and related to inflow of discharged waters. A total of 157 and 106 of phytoplankton and zooplankton species were recorded, respectively. The average plankton population was 4 × 106 cells l-1 in terms of phytoplankton and 24 × 103 ind. m-3 in terms of zooplankton. Seasonal differences in the quantitative and qualitative composition of both communities in the different stations were marked. Eutreptiella belonging to class Euglenophyceae overwhelming during spring, reaching an average of 17 × 106 cells l-1. The genus previously was recorded as rare form in the Egyptian waters and may have been introduced via ballast water. Except in spring, copepods were the most abundant group and tintinnid abundances generally increased in spring. The ranges of Shannon diversity indices indicate disturbance level and sometimes high productivity. Salinity, dissolved oxygen and pH may be responsible for the variations in phytoplankton and zooplankton community structure. The results indicate that not only the discharged water make the harbour at risk, but also the ballast water is not less dangerous, and so, we emphasize the need for activation of the ballast water management IMO Ballast Water Management Conventions to reduce the risk of future species invasions.

20

Short-term variation in zooplankton community from Daya Bay with outbreaks of Penilia avirostris

Li K., Yin J., Tan Y., Huang L., Song X.

Oceanologia

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2014

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No. 56 (3)

583--602

EN

The zooplankton community structure in bays fluctuates as a result of anthropogenic activities in such waters. We focused on the short-term variability of a zooplankton community and compared its differences at the outflow of a nuclear power plant (ONPP), in a marine cage-culture area (MCCA) and in unpolluted waters (UW) in the south-west part of Daya Bay from 28 April to 1 June 2001. Environmental factors and zooplankton abundance differed significantly among stations at ONPP, MCCA and UW: high temperatures and a high zooplankton abundance occurred at ONPP, while a high chlorophyll a concentration and a low zooplankton abundance prevailed in MCCA. Statistical analysis revealed that the zooplankton diversity and abundance could be reduced by the activity of the marine cage-culture in a short time. Penilia avirostris made up an important component of the zooplankton in the study area, its abundance ranging widely from 16 to 7267 indiv. m-3 from April to June and peaking at the ONPP outflow. The outbreak of P. avirostris probably resulted from the combined effects of favourable water temperature, food concentration and its parthenogenetic behaviour.