scholarly journals Bayesian Network Analysis reveals resilience of the jellyfish Aurelia aurita to an Irish Sea regime shift

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Emily G. Mitchell ◽  
Margaret I. Wallace ◽  
V. Anne Smith ◽  
Amanda A. Wiesenthal ◽  
Andrew S. Brierley
Keyword(s):  
Regime Shift ◽  
Zooplankton Community ◽  
Aurelia Aurita ◽  
Irish Sea ◽  
Zooplankton Abundance ◽  
Abundance Data ◽  
Spatial Dependencies ◽  
The Irish Sea ◽  
Zooplankton Communities ◽  
Jellyfish Abundance

AbstractRobust time-series of direct observations of jellyfish abundance are not available for many ecosystems, leaving it difficult to determine changes in jellyfish abundance, the possible causes (e.g. climate change) or the consequences (e.g. trophic cascades). We sought an indirect ecological route to reconstruct jellyfish abundance in the Irish Sea: since zooplankton are jellyfish prey, historic variability in zooplankton communities may provide proxies for jellyfish abundance. We determined the Bayesian ecological network of jellyfish–zooplankton dependencies using jellyfish- and zooplankton-abundance data obtained using nets during a 2-week cruise to the Irish Sea in 2008. This network revealed that Aurelia aurita abundance was dependent on zooplankton groups Warm Temperate and Temperate Oceanic as defined by previous zooplankton ecology work. We then determined historic zooplankton networks across the Irish Sea from abundance data from Continuous Plankton Recorder surveys conducted between 1970 and 2000. Transposing the 2008 spatial dependencies onto the historic networks revealed that Aurelia abundance was more strongly dependent over time on sea surface temperature than on the zooplankton community. The generalist predatory abilities of Aurelia may have insulated this jellyfish over the 1985 regime shift when zooplankton composition in the Irish Sea changed abruptly, and also help explain its globally widespread distribution.

Environmental drivers of a decline in a coastal zooplankton community

2021 ◽  
Author(s):  
Seòna R Wells ◽  
Eileen Bresnan ◽  
Kathryn Cook ◽  
Dafne Eerkes-Medrano ◽  
Margarita Machairopoulou ◽  
...  
Keyword(s):  
Zooplankton Community ◽  
Water Masses ◽  
Environmental Drivers ◽  
High Temporal Resolution ◽  
Monitoring Site ◽  
Zooplankton Abundance ◽  
Offshore Water ◽  
Additive Mixed Models ◽  
Zooplankton Communities

Abstract Major changes in North Atlantic zooplankton communities in recent decades have been linked to climate change but the roles of environmental drivers are often complex. High temporal resolution data is required to disentangle the natural seasonal drivers from additional sources of variability in highly heterogeneous marine systems. Here, physical and plankton abundance data spanning 2003–2017 from a weekly long-term monitoring site on the west coast of Scotland were used to investigate the cause of an increasing decline to approximately -80± 5% in annual average total zooplankton abundance from 2011 to 2017. Generalized additive mixed models (GAMMs), with an autoregressive correlation structure, were used to examine seasonal and inter-annual trends in zooplankton abundance and their relationship with environmental variables. Substantial declines were detected across all dominant taxa, with ∼ 30–70% of the declines in abundance explained by a concurrent negative trend in salinity, alongside the seasonal cycle, with the additional significance of food availability found for some taxa. Temperature was found to drive seasonal variation but not the long-term trends in the zooplankton community. The reduction in salinity had the largest effect on several important taxa. Salinity changes could partly be explained by locally higher freshwater run-off driven by precipitation as well as potential links to changes in offshore water masses. The results highlight that changes in salinity, caused by either freshwater input (expected from climate predictions) or fresher offshore water masses, may adversely impact coastal zooplankton communities and the predators that depend on them.

Large-scale sampling reveals the spatio-temporal distributions of the jellyfish Aurelia aurita and Cyanea capillata in the Irish Sea

2011 ◽  
Vol 158 (12) ◽  
pp. 2639-2652 ◽  
Author(s):  
Thomas Bastian ◽  
Damien Haberlin ◽  
Jennifer E. Purcell ◽  
Graeme C. Hays ◽  
John Davenport ◽  
...  
Keyword(s):  
Large Scale ◽  
Aurelia Aurita ◽  
Irish Sea ◽  
Cyanea Capillata ◽  
Spatio Temporal ◽  
The Irish Sea

8. The Effect of Bythotrephes Longimanus on the Size Structure of Zooplankton Communities in the Muskoka Region, Ontario

2017 ◽  
Author(s):  
Johanna Pokorny
Keyword(s):  
Large Scale ◽  
Size Structure ◽  
Scale Effects ◽  
Regional Scale ◽  
Zooplankton Community ◽  
Zooplankton Abundance ◽  
Bythotrephes Longimanus ◽  
Zooplankton Species ◽  
Community Size ◽  
Zooplankton Communities

Invasive species are considered the greatest threat to aquatic ecosystem biodiversity. Bythotrephes longimanus, an exotic zooplankton species introduced to North America in the 1980s, is threatening the structure of indigenous aquatic ecosystems as it continues to invade inland Ontario lakes. As a predacious zooplankton species, B. longimanus has been shown to decrease zooplankton abundance, species richness and shift zooplankton community size structure in invaded lakes. However, much of the previous research concerning the predatory effects of B. longimanus has been on surveys of a small number of lakes or has been in controlled mesocosm or lab-based experiments. This study examines the effects of B. longimanus on the zooplankton community using size-structure characterizations (grouping individuals from the community based on size) as community measures for 311 lakes in the Muskoka Region, a highly invaded watershed in Southern Ontario. More specifically, the study explores the size-spectra of invaded versus uninvaded lakes, with reference to an array of environmental lake characteristics (water chemistry, lake morphometry,etc.), and the relevance of B. longimanus activity on the regional scale. By using such a large-scale survey we will be able to appreciate regional-scale effects, as well as encompass the multiple and more indirect trophic interactions that B. longimanus is likely having with the entire aquatic community. (Funding: NSERC & CAISN.)

Planktivory by the predacious cladoceran Bythotrephes longimanus: effects on zooplankton size structure and abundance

1999 ◽  
Vol 56 (10) ◽  
pp. 1865-1872 ◽  
Author(s):  
Eva Wahlström ◽  
Erika Westman
Keyword(s):  
Size Structure ◽  
Zooplankton Community ◽  
Zooplankton Biomass ◽  
Zooplankton Abundance ◽  
Large Species ◽  
Bythotrephes Longimanus ◽  
Total Zooplankton ◽  
Natural Systems ◽  
Phytoplankton Communities ◽  
Zooplankton Communities

In order to study density-dependent effects of invertebrate planktivory, four different densities of Bythotrephes longimanus were inoculated into mesocosm enclosures with a mixed zooplankton community. Changes in size structure and abundance of zooplankton and phytoplankton communities were recorded over a period of 3 weeks. High densities of Bythotrephes were able to reduce total zooplankton abundance, which was mainly due to a decrease in the density of the relatively large species Holopedium gibberum. The density of the smaller species Bosmina longirostris was also reduced with increasing densities of Bythotrephes, whereas rotifer abundance remained largely unaffected. The mean size of Holopedium increased with increasing densities of Bythotrephes. Despite the decrease in total zooplankton biomass in high-Bythotrephes treatments, no effect of Bythotrephes density on primary producers was observed. Our experiment shows that predacious cladocerans may reduce macrozooplankton biomass, large as well as small species. Predation from invertebrate planktivores results in a zooplankton community consisting of larger individuals. Comparing our experimental densities with densities of Bythotrephes found in natural systems suggests that invertebrate planktivores may influence size structure and abundance of zooplankton communities even in lakes with planktivorous fish.

scholarly journals Biomass size spectra of mesozooplankton in the Chukchi Sea during the summers of 1991/1992 and 2007/2008: an analysis using optical plankton counter data

2012 ◽  
Vol 69 (7) ◽  
pp. 1205-1217 ◽  
Author(s):  
Kohei Matsuno ◽  
Atsushi Yamaguchi ◽  
Ichiro Imai
Keyword(s):  
Chukchi Sea ◽  
Zooplankton Community ◽  
Dry Mass ◽  
Zooplankton Abundance ◽  
Sea Ice Extent ◽  
Size Spectra ◽  
Spherical Diameter ◽  
Group B ◽  
Zooplankton Communities ◽  
Counter Data

Abstract Matsuno, K., Yamaguchi, A., and Imai, I. 2012. Biomass size spectra of mesozooplankton in the Chukchi Sea during the summers of 1991/1992 and 2007/2008: an analysis using optical plankton counter data. – ICES Journal of Marine Science, 69: . An optical plankton counter was used to examine the regional characteristics of the zooplankton communities in the Chukchi Sea during the summers of 1991, 1992, 2007, and 2008. Zooplankton abundance and biomass ranged from 5000 to 1 170 000 ind. m−2 and 0.2 to 10.9 g dry mass m−2, respectively. Based on zooplankton biovolume in equivalent spherical diameter (ESD) in 48 bins, one every 0.1 mm between 0.25 and 5.0 mm, a Bray–Curtis cluster analysis classified zooplankton communities into four groups (A–D). No changes were observed in zooplankton communities south of the Lisburne Peninsula (group A) throughout the 4 years, but there were differences north of the Peninsula, with group B (normal, intermediate biomass) observed in 1991/1992, group D (low biomass) in 2007, and group C (predominance of barnacle larvae) in 2008. Analysis of the normalized biomass size spectra for the groups indicated that groups A and C were very productive, so the zooplankton community south of the Lisburne Peninsula was consistently highly productive, which may be because of the continuous inflow of Pacific Water rich in nutrients. Zooplankton communities north of the Lisburne Peninsula varied greatly from year to year, which may be related to interannual changes in sea-ice extent.

scholarly journals Western Pacific Zooplankton Community along Latitudinal and Equatorial Transects in Autumn 2017 (Northern Hemisphere)

Diversity ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 58
Author(s):  
Yi Long ◽  
Md Abu Noman ◽  
Dawei Chen ◽  
Shihao Wang ◽  
Hao Yu ◽  
...  
Keyword(s):  
Chlorophyll A ◽  
Diversity Index ◽  
Zooplankton Community ◽  
Western Pacific ◽  
Zooplankton Abundance ◽  
Oithona Similis ◽  
Subtropical Countercurrent ◽  
Wiener Diversity Index ◽  
Zooplankton Communities ◽  
The Western Pacific

During the autumn of 2017, a study was conducted to assess the zooplankton community composition in three sections (two latitudinal, going from Japan to the equator, and one longitudinal on the equator) of the Western Pacific Ocean. A total of 384 species of zooplankton adults and 21 groups of zooplankton larvae were identified, with copepods being the predominant taxon. The common dominant species across the three sections were Acrocalanus gibber, Canthocalanus pauper, Oithona similis, Paracalanus aculeatus, and Oncaea venusta. Zooplankton abundance was the highest in the equator section, with a mean abundance of 258.94 ± 52.57 ind./m3. Comparatively, a low abundance was recovered from the Subtropical Countercurrent (STCC) region, while the highest abundance holding stations were located in the eastern equatorial and North Equatorial Countercurrent (NECC) regions. Pearson’s correlation, canonical correspondence analysis, and other methods were used to analyze the relationship between environmental factors and zooplankton. We found that the Shannon–Wiener diversity index and Pielou’s uniformity index were significantly correlated (p < 0.05) with concentrations of nitrite and chlorophyll a. The distribution of zooplankton was also limited by nutrients, chlorophyll a, and dissolved oxygen. In addition, we reveal differences in the abundance of species in the equatorial and latitudinal seas. We found that not only temperature and nutrient salinity, but also ocean currents and the movement of water masses, influence the distribution of zooplankton communities in the Western Pacific.

scholarly journals Assessment of zooplankton community in an anthropogenic-disturbance coastal creek, southwest Nigeria

2021 ◽  
Vol 6 (2) ◽  
pp. 160-169
Author(s):  
Kayode James Balogun ◽  
Emmanuel Kolawole Ajani
Keyword(s):  
Water Depth ◽  
Water Samples ◽  
Anthropogenic Disturbance ◽  
Abiotic Factors ◽  
Zooplankton Community ◽  
Diversity Indices ◽  
Zooplankton Abundance ◽  
Southwest Nigeria ◽  
Binocular Microscope ◽  
Zooplankton Communities

In order to assess the zooplankton community in an anthropogenic-disturbance Badagry creek, Zooplankton and water samples were collected and analyzed bi-monthly from November 2011 to September 2013 in nine stations representing its three different zones using standard methods. Zooplankton was identified to species-level using relevant texts and counted under a Microstar IV Carl Zeiss binocular microscope calibrated at different magnifications. Diversity was determined using Shannon-Weiner (H), Simpson (1-D) and Evenness (e^H/S) indices. Water samples were analysed for temperature, pH, salinity, conductivity, turbidity, dissolved oxygen, water depth and nitrate. Data were analysed using descriptive statistics, ANOVA, cluster and Canonical correspondence analysis (CCA) at α = 0.05. A total of 56 species comprising 26 species of rotifers, 15 species of arthropoda, 4 species of ciliophora, 3 species of cnidaria, and 2 species of ctenophora, foraminifera, mollusca, protozoa each, with an array of meroplankton / juvenile stages of the order copepod of subphylum crustacea were recorded. Diversity indices were highest (H = 2.20; 1-D = 0.80; e^H/S = 0.27) at station 6 and lowest in station 8 (H = 1.20; 1-D = 0.56) and station 1(e^H/S = 0.14). Salinity/conductivity, nitrate and water depth were significantly different (p < 0.05) among the study stations. CCA revealed salinity/conductivity and nitrate were the most important abiotic factors co-related with the zooplankton abundance in Badagry creek. The moderately low zooplankton communities’ diversity and abundance in Badagry creek point at different natural and anthropogenic factor impacts.

Zooplankton Community Structure in the North Sea and Northeast Atlantic: Development and Test of a Biological Model

1983 ◽  
Vol 40 (11) ◽  
pp. 1912-1924 ◽  
Author(s):  
J. Anthony Koslow
Keyword(s):  
North Sea ◽  
Size Structure ◽  
Zooplankton Community ◽  
Major Elements ◽  
Zooplankton Abundance ◽  
Zooplankton Community Structure ◽  
Marine Zooplankton ◽  
Physical Forcing ◽  
The North ◽  
Zooplankton Communities

A simulation model was used to examine whether predatory interactions may regulate the size structure of marine zooplankton communities, as observed in many freshwater systems. Results of the model were consistent with the freshwater studies, such that large increases or decreases in planktivorous fish led to the dominance of small or large zooplankters, respectively. However, model predictions were not consistent with the recent decline in the northeastern Atlantic of most major elements of the pelagic zooplankton community along with North Sea herring and mackerel stocks. The overall decline of the pelagic community throughout this region indicates that zooplankton abundance may be regulated by physical forcing, and that these populations may be food- rather than predator-limited. Realistic ecological simulations of marine pelagic systems may require more complex two-layer models allowing for the effects of vertical migration, and with day–night differences in food availability and selectivity.

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