Research

23 pages, 7862 KiB

Open AccessArticle

Invasion of Bythotrephes longimanus and Cercopagis pengoi in Lake Champlain: Impacts on the Native Zooplankton Community

by Zachary A. Cutter, Timothy B. Mihuc and Luke W. Myers

Diversity 2023, 15(11), 1112; https://doi.org/10.3390/d15111112 - 25 Oct 2023

Viewed by 874

Abstract

The zooplankton community of Lake Champlain has been altered over the past decade due to the introduction of two predatory zooplankton species. Bythotrephes longimanus Leydig, 1860 was first detected in Lake Champlain in August 2014, and Cercopagis pengoi (Ostroumov, 1891) was detected in [...] Read more.

The zooplankton community of Lake Champlain has been altered over the past decade due to the introduction of two predatory zooplankton species. Bythotrephes longimanus Leydig, 1860 was first detected in Lake Champlain in August 2014, and Cercopagis pengoi (Ostroumov, 1891) was detected in August 2018. Monitoring for both invasive species at 15 lake sites using whole water tow sampling has been ongoing since 2010 with no detection of either species until 2014. Utilizing data from the Lake Champlain long-term monitoring program, we assessed pre- and post-invasion population dynamics of both invasive species on the native zooplankton community. Our results showed shifts in community structure following invasion, including a reduction in Diacyclops thomasi (Forbes, 1882) populations by both invaders and a reduction in Daphnia retrocurva Forbes, 1882 following the introduction of B. longimanus. Other cyclopoids, bosminids, and rotifers were also reduced, corresponding to both introduced species. The native large-bodied plankton predator Leptodora kindtii (Focke, 1844) appears to be unable to coexist with either invasive predatory cladoceran, displaying seasonal partitioning between L. kindtii and the Cercopagidae. These findings suggest that the invasion of both large predators in Lake Champlain have impacted pelagic zooplankton community structure. Full article

(This article belongs to the Special Issue Advances in the Diversity and Ecology of Zooplankton)

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22 pages, 7632 KiB

Open AccessArticle

Dynamics of Zooplankton along the Romanian Black Sea Coastline: Temporal Variation, Community Structure, and Environmental Drivers

by Elena Bișinicu, Luminița Lazăr and Florin Timofte

Diversity 2023, 15(9), 1024; https://doi.org/10.3390/d15091024 - 20 Sep 2023

Viewed by 976

Abstract

Between 2013 and 2020, a total of 27 distinct zooplankton taxa, encompassing both holoplanktonic and meroplanktonic organisms spanning different classes and orders, were successfully identified along the Romanian Black Sea coastline. The seasonal dispersion patterns of these zooplankton taxa revealed a notable augmentation [...] Read more.

Between 2013 and 2020, a total of 27 distinct zooplankton taxa, encompassing both holoplanktonic and meroplanktonic organisms spanning different classes and orders, were successfully identified along the Romanian Black Sea coastline. The seasonal dispersion patterns of these zooplankton taxa revealed a notable augmentation in species identification during the warmer periods, contrasting with reduced zooplankton diversity during the colder seasons. This phenomenon was underscored by the outcomes of SIMPER analysis, which highlighted that copepods, meroplankton, and cladocerans predominantly contributed to the community structure during warmer seasons. In contrast, during colder seasons, cladocerans were scarcely represented, and the density levels of copepods and meroplankton were diminished. From a quantitative perspective, the dinoflagellate Noctiluca scintillans, exhibited its highest density and biomass during the warm season, with a relatively lower representation during colder periods. The variation in the abundance of zooplankton was closely linked to changes in salinity and temperature, culminating in noticeable fluctuations, which were particularly evident during the cold season. During this period, the values of zooplankton abundance were notably lower compared to those observed in the warmer season. The comprehension of zooplankton dynamics stands as a critical facet for assessing biodiversity, monitoring ecosystem well-being, and guiding conservation endeavours. Full article

(This article belongs to the Special Issue Advances in the Diversity and Ecology of Zooplankton)

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23 pages, 3359 KiB

Open AccessArticle

The Diversity of Fish Larvae in the Bons Sinais Estuary (Mozambique) and Its Role as a Nursery to Marine Fish Resources

by Jeremias Mocuba, Francisco Leitão and Maria Alexandra Teodósio

Diversity 2023, 15(8), 883; https://doi.org/10.3390/d15080883 - 25 Jul 2023

Cited by 1 | Viewed by 912

Abstract

The study of assemblages of fish in their early phases in estuaries is an essential approach to understanding the functioning of these types of ecosystems and their role as nursery grounds for some marine fish species. The main aim of this study was [...] Read more.

The study of assemblages of fish in their early phases in estuaries is an essential approach to understanding the functioning of these types of ecosystems and their role as nursery grounds for some marine fish species. The main aim of this study was to analyze the ichthyoplankton assemblage in the Bons Sinais Estuary, specifically to clarify the use of this area by species of socio-economic interest. This study identified 22 fish larval taxa among families, genera, and species. Gobiidae (54%), a group of resident species, dominated the community. The larval taxa of socio-economic importance (Thryssa sp., Clupeidae, Sillago sihama, Johnius dussumieri, Pellona ditchela, Pomadasys kaakan, Cichlidae, and Mugilidae) accounted for 23% of the total abundance. Larval density (N°/100 m³) varied spatially and temporally, with higher density and diversity values both in the middle zone and in the wet season. Multivariate analyses revealed that salinity, temperature, and water transparency had a strong influence on larval abundance and density. While most fish larvae were in the post-flexion stage, there was a predominance of pre-flexion larvae in the lower estuary and in the post-flexion stage in the middle and upper zones, especially for marine fish resources, showing the role of this estuarine habitat as a nursery area. Full article

(This article belongs to the Special Issue Advances in the Diversity and Ecology of Zooplankton)

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11 pages, 1591 KiB

Open AccessArticle

Use of Formalin-Preserved Collections to Infer Trophic Indicators of Marine Zooplankton from Stable Isotopes

by Antonio Bode, Jaime Otero, Ángel F. Lamas and Carmen Mompeán

Diversity 2023, 15(3), 459; https://doi.org/10.3390/d15030459 - 20 Mar 2023

Viewed by 1061

Abstract

Formalin preservation affects the stable isotope composition of zooplankton samples, thus limiting the analysis of valuable collections covering large time intervals. Here, we compare different procedures for correcting the bias caused by formalin in δ¹³C and δ¹⁵N of zooplankton [...] Read more.

Formalin preservation affects the stable isotope composition of zooplankton samples, thus limiting the analysis of valuable collections covering large time intervals. Here, we compare different procedures for correcting the bias caused by formalin in δ¹³C and δ¹⁵N of zooplankton community samples. Zooplankton samples representative of seasonal variations in the period 2000–2009 were collected off A Coruña (NW Spain). Part of the sample was immediately dried and analysed for δ¹³C, δ¹⁵N, and elemental composition within 3 years of collection. These values were used as the unpreserved reference. The remaining sample was preserved in 4% formaldehyde and aliquots obtained after a period ranging from 3 years to more than 10 years of storage were analysed as the originally dried samples. Additionally, the copepod fraction of total biomass was determined in the preserved samples. Corrections of formalin effects based on ordinary least squares regression had large uncertainties, while mass balance corrections based on the change in C:N ratio (only possible for δ¹³C) overestimated reference values. However, either simple corrections based on the mean difference between values in dry and preserved samples or more complex generalised additive models considering seasonality, copepod biomass, and time of sample storage, produced estimations with relatively low uncertainty. Our results highlight the importance of determining specific correction solutions for each preserved collection before reconstructing stable isotope time series. Furthermore, the uncertainties associated with the estimates can be used in sensitivity analysis to assess their potential impact on the interpretation of the series. Full article

(This article belongs to the Special Issue Advances in the Diversity and Ecology of Zooplankton)

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12 pages, 1229 KiB

Open AccessArticle

Assessing the Zooplankton Metacommunity (Branchiopoda and Copepoda) from Mediterranean Wetlands in Agricultural Landscapes

by Juan Diego Gilbert, Francisco J. Márquez and Francisco Guerrero

Diversity 2023, 15(3), 362; https://doi.org/10.3390/d15030362 - 02 Mar 2023

Cited by 2 | Viewed by 1353

Abstract

Mediterranean wetlands are suitable ecosystems for studying metacommunity theory, since they are isolated ecosystems within a land matrix with well-established limits, often with watersheds destined for agricultural uses. The zooplankton community of wetlands in agricultural landscapes is the result of processes that operate [...] Read more.

Mediterranean wetlands are suitable ecosystems for studying metacommunity theory, since they are isolated ecosystems within a land matrix with well-established limits, often with watersheds destined for agricultural uses. The zooplankton community of wetlands in agricultural landscapes is the result of processes that operate in a different multiscale context. We selected 24 ponds in Alto Guadalquivir region (SE Spain) with different local environmental variables (biological, limnological and land uses). The zooplankton community of the wetlands under study consists of a total of 60 species: 38 branchiopods and 22 copepods. This community (total, branchiopods and copepods) was analysed through two different and complementary metacommunity approaches. The pattern approach determines the species distribution along environmental gradients, and the mechanistic approach considers the involved processes, such as environmental control and dispersal limitation. The results indicated a nested metacommunity, in which five limnological variables, three land uses and six spatial variables are the main drivers that explain zooplankton distribution in these wetlands. In conclusion, species sorting and dispersal processes play a role in the structuring of the zooplankton metacommunity. This conclusion has implications for the development of adequate management policies on Mediterranean wetland protection and diversity conservation in agricultural contexts. Full article

(This article belongs to the Special Issue Advances in the Diversity and Ecology of Zooplankton)

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16 pages, 3108 KiB

Open AccessArticle

Structural Organization of Zooplankton Communities in Different Types of River Mouth Areas

by Vyacheslav Zhikharev, Dmitry Gavrilko, Ivan Kudrin, Ekaterina Vodeneeva, Oksana Erina, Maria Tereshina and Galina Shurganova

Diversity 2023, 15(2), 199; https://doi.org/10.3390/d15020199 - 01 Feb 2023

Cited by 1 | Viewed by 1528

Abstract

The gradients of hydrological, hydrophysical, and hydrochemical conditions form the transition zones in river mouth areas. These areas are considered ecotones in the presence of the edge effect. Our research aimed to identify the main patterns in the structural organization of zooplankton communities [...] Read more.

The gradients of hydrological, hydrophysical, and hydrochemical conditions form the transition zones in river mouth areas. These areas are considered ecotones in the presence of the edge effect. Our research aimed to identify the main patterns in the structural organization of zooplankton communities in different types of river mouth areas in lowland reservoir tributaries within the Middle Volga basin. A cluster analysis was performed to structure and determine the zooplankton communities. The identified zooplankton communities were characterized by the noticeable heterogeneity in the species structure. We analyzed the spatial distribution of the structural indicators of zooplankton communities and, on the basis of RDA, determined the factors that significantly affect the organization of the ecotone community. An ecotone was found in all types of river mouth areas where the highest density, biomass, diversity, species, and functional richness of zooplankton were noted, as compared to bordering zooplankton communities. As the morphological structure of the mouth areas became more complex, the values of the main structural parameters of zooplankton communities increased. It was demonstrated that conditions in the ecotones are favorable to the development of zooplankton alien species. The major factors determining the species structure of the ecotone zooplankton community were water electrical conductivity (R² = 21.07%, p-value = 0.001), dissolved oxygen content (R² = 10.33%, p-value = 0.003), and water transparency (R² = 9.77 %, p-value = 0.001). Full article

(This article belongs to the Special Issue Advances in the Diversity and Ecology of Zooplankton)

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20 pages, 2349 KiB

Open AccessArticle

Genetic Detection and a Method to Study the Ecology of Deadly Cubozoan Jellyfish

by Scott J. Morrissey, Dean R. Jerry and Michael J. Kingsford

Diversity 2022, 14(12), 1139; https://doi.org/10.3390/d14121139 - 19 Dec 2022

Cited by 3 | Viewed by 2233

Abstract

Cubozoan jellyfish pose a risk of envenomation to humans and a threat to many businesses, yet crucial gaps exist in determining threats to stakeholders and understanding their ecology. Environmental DNA (eDNA) provides a cost-effective method for detection that is less labour intensive and [...] Read more.

Cubozoan jellyfish pose a risk of envenomation to humans and a threat to many businesses, yet crucial gaps exist in determining threats to stakeholders and understanding their ecology. Environmental DNA (eDNA) provides a cost-effective method for detection that is less labour intensive and provides a higher probability of detection. The objective of this study was to develop, optimise and trial the use of eDNA to detect the Australian box jellyfish, Chironex fleckeri. This species was the focus of this study as it is known to have the strongest venom of any cubozoan; it is responsible for more than 200 recorded deaths in the Indo-Pacific region. Further, its ecology is poorly known. Herein, a specific and sensitive probe-based assay, multiplexed with an endogenous control assay, was developed, and successfully utilised to detect the deadly jellyfish species and differentiate them from closely related taxa. A rapid eDNA decay rate of greater than 99% within 27 h was found with no detectable influence from temperature. The robustness of the technique indicates that it will be of high utility for detection and to address knowledge gaps in the ecology of C. fleckeri; further, it has broad applicability to other types of zooplankton. Full article

(This article belongs to the Special Issue Advances in the Diversity and Ecology of Zooplankton)

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14 pages, 1826 KiB

Open AccessArticle

Thermal Tolerance of Cyclops bohater (Crustacea: Copepoda); Selection of Optimal and Avoided Conditions in Experimental Conditions

by Valentina Lazareva, Tatyana Mayor, Olga Malysheva, Elena Medyantseva, Svetlana Zhdanova, Andrey Grishanin and Vladimir Verbitsky

Diversity 2022, 14(12), 1106; https://doi.org/10.3390/d14121106 - 12 Dec 2022

Viewed by 1317

Abstract

Temperature adaptations of ectothermic species as well as the plasticity of their thermal strategies are important for survival during temperature fluctuations, in particular, caused by global warming. The critical thermal maximum (CTM)—the values of the water temperature at which heat shock was noted [...] Read more.

Temperature adaptations of ectothermic species as well as the plasticity of their thermal strategies are important for survival during temperature fluctuations, in particular, caused by global warming. The critical thermal maximum (CTM)—the values of the water temperature at which heat shock was noted (loss of motor activity in case of copepods) was determined under laboratory conditions. The “chronic” method was used to identify the temperature preferences of the copepods in which a group of test organisms are placed into a thermogradient apparatus. The main result is that in the experiment for individuals of the summer generation C. bohater, the optimal thermal conditions (FTP) were within 6–11 °C. Summer generation of this copepod in natural water bodies develops at a temperature of 5–12 °C, which is close to FTP in the experiment. At the same time, the thermal resistance of C. bohater (CTM 31.5 °C) was found to be the lowest among the species of the genus Cyclops. The differences between the thermal preferences of the winter and summer generations expand the temperature of normal performance (TNP) range and indicate a high physiological plasticity of the C. bohater population. This property is likely to allow C. bohater to survive as the climate continues to warm. Full article

(This article belongs to the Special Issue Advances in the Diversity and Ecology of Zooplankton)

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