Has zooplankton 24 hour vertical distribution pattern in Lough Derg (Ireland) been changed over the period of ∼90 years?

2011 ◽  
Vol 40 (3) ◽  
Author(s):  
Agnieszka Pociecha ◽  
Thomas McCarthy
Keyword(s):  
Vertical Distribution ◽  
Zebra Mussel ◽  
Diel Vertical Migration ◽  
Food Concentration ◽  
Species Level ◽  
Total Zooplankton ◽  
Vertical Distribution Pattern ◽  
Cladoceran Species ◽  
Zooplankton Density ◽  
The Vertical Distribution

AbstractThe vertical distribution of zooplankton was examined in Lough Derg, Ireland. Zooplankton was collected at one location every 2 m from the surface to the bottom during 24 hours at four-hour intervals. Zooplankton was identified to the species level and its density was calculated for each taxon, depth and hour. We recorded 9 rotifer, 3 copepod, and 4 cladoceran species. The highest total zooplankton density (rotifers, copepods, cladocerans, mysids and zebra mussel larvae) was recorded at 3 a.m. Rotifers preferred mainly a depth from 0 to 8 m, while copepods and cladocerans were observed within the whole water column during a 24 hour observation. It was a different pattern of diurnal migration than that Southern and Gardiner (1932) received, though they didn’t study rotifers. Probably food concentration and/or predators, or other environmental factors could influence the diel vertical migration of zooplankton from Loug Derg.

Vertical distribution pattern of naidids in granular activated carbon filters and potential technology to control their penetration risk

2018 ◽  
Vol 18 (6) ◽  
pp. 1976-1983
Author(s):  
Xiao-Bao Nie ◽  
Yun-Zi Tang ◽  
Chang-bo Jiang ◽  
Yuan-Nan Long ◽  
Pan-Pan He ◽  
...  
Keyword(s):  
Drinking Water ◽  
Activated Carbon ◽  
Vertical Distribution ◽  
Distribution Pattern ◽  
Granular Activated Carbon ◽  
Distribution Patterns ◽  
Distribution Data ◽  
Vertical Distribution Pattern ◽  
Filter Bed ◽  
The Vertical Distribution

Abstract Aquatic worms propagated in granular activated carbon (GAC) filter has become a troublesome problem for drinking water supply. This study investigated the vertical distribution patterns of naidids in GAC filter beds and assessed the effect of an additional sand bed, located below the GAC bed, in preventing naidids from being present in effluent. The results indicated that the vertical distribution data of naidids in the GAC filter bed were well fitted by a Gaussian distribution, and the location of peak population density was mainly affected by downward flow. Backwashing experiments revealed that additional pressure air scouring shifted the distribution pattern of naidids in the GAC filter bed, resulting in a significant enhancement in naidid removal efficiency. Additionally, the addition of a sand bed exhibited pronounced interception and inactivation effects on naidids, suggesting that it may be a very promising technology for preventing naidids propagated in GAC filters from being present in the effluent.

scholarly journals Assembly history modulates vertical root distribution in a grassland experiment

2021 ◽  
Author(s):  
Inés M. Alonso-Crespo ◽  
Emanuela W.A. Weidlich ◽  
Vicky M. Temperton ◽  
Benjamin M. Delory
Keyword(s):  
Vertical Distribution ◽  
Functional Groups ◽  
Plant Communities ◽  
Functional Group ◽  
Species Level ◽  
The Other ◽  
Priority Effects ◽  
Rooting Depth ◽  
Distribution Of Roots ◽  
The Vertical Distribution

The order of arrival of plant species during assembly can affect the structure and functioning of grassland communities. These so-called priority effects have been extensively studied aboveground, but we still do not know how they affect the vertical distribution of roots in the soil and the rooting depth of plant communities. To test this hypothesis, we manipulated the order of arrival of three plant functional groups (forbs, grasses and legumes) in a rhizobox experiment. Priority effects were created by sowing one functional group 10 days before the other two. Rhizoboxes in which all functional groups were sown simultaneously were used as controls. During the experiment, the mean rooting depth of plant communities was monitored using image analysis and a new methodological approach using deep learning (RootPainter) for root segmentation. At harvest, we measured aboveground (community and species level) and belowground (community level) biomass, and assessed the vertical distribution of the root biomass in different soil layers. At the community level, all scenarios where one functional group was sown before the other two had similar shoot and root productivity. At the species level, two forbs (Achillea millefolium and Centaurea jacea) benefited from arriving early, and one legume (Trifolium pratense) had a disadvantage when it was sown after the grasses. Priority effect treatments also affected the vertical distribution of roots. When grasses were sown first, plant communities rooted more shallowly than when forbs or legumes were sown first,. In addition, roots moved down the soil profile 24% more slowly in grasses-first communities. Our results highlight that plant functional group order of arrival in grassland communities can affect the vertical distribution of roots in the soil and this may have implications for species coexistence.

Diel vertical migration: A possible host-finding mechanism in salmon louse (Lepeophtheirus salmonis) copepodids?

1995 ◽  
Vol 52 (4) ◽  
pp. 681-689 ◽  
Author(s):  
Peter Andreas Heuch ◽  
Aengus Parsons ◽  
Karin Boxaspen
Keyword(s):  
Light Intensity ◽  
Vertical Distribution ◽  
Vertical Migration ◽  
Diel Vertical Migration ◽  
Host Finding ◽  
Migration Pattern ◽  
Lepeophtheirus Salmonis ◽  
Salmon Louse ◽  
Night And Day ◽  
The Vertical Distribution

The vertical distribution of pelagic nauplii and copepodids of the salmon louse Lepeophtheirus salmonis Krøyer was studied in large enclosures in the sea. Copepodids, which infect salmonid hosts, displayed a distinct diel vertical migration pattern. They gathered near the surface during the day, and spread out into deeper layers at night. Nauplii showed only small differences in depth between night and day. Copepodid distribution seems to be controlled by light intensity; no effect of either salinity or temperature was found. This migration pattern, which is the reverse of that of wild salmonids, may increase the number of parasite–host encounters as hosts will swim through populations of sinking (nighttime) and rising (dawn) parasites every 24 h. Because caged salmon feed at the surface during the day, they are likely to be more exposed to infective copepodids than wild fish.

scholarly journals Diel changes in the vertical distribution of larval cutlassfish Trichiurus japonicus

2018 ◽  
Vol 99 (2) ◽  
pp. 517-523
Author(s):  
Daichi Uehara ◽  
Jun Shoji ◽  
Yuichiro Ochi ◽  
Shuhei Yamaguchi ◽  
Kazumitsu Nakaguchi ◽  
...  
Keyword(s):  
Vertical Distribution ◽  
Vertical Migration ◽  
Similar Pattern ◽  
Diel Vertical Migration ◽  
Seto Inland Sea ◽  
Upward Movement ◽  
Swim Bladder ◽  
Diel Changes ◽  
Trichiurus Japonicus ◽  
The Vertical Distribution

Diel vertical migration of the cutlassfish Trichiurus japonicus larvae were investigated by consecutive 24-h collections at 3-h intervals at a station in the central Seto Inland Sea, Japan in June and September. Only one larva was collected in June 2017, while 224 and 40 larvae were collected in September 2016 and 2017, respectively. Larvae were present only at depths of ≥ 11 m during the day, whereas they were present at depths of 1, 6, 11 and 16 m during the night. Migration was observed in larvae in which swim bladder formation was completed. A similar pattern, namely nocturnal occurrence at shallow depths only of the developed larvae, was observed in another 24-h survey, suggesting that the swim bladder regulates the upward movement of larvae at night.

scholarly journals The Vertical Distribution Pattern of Microbial- and Plant-Derived Carbon in the Rhizosphere in Alpine Coniferous Forests

2021 ◽  
Author(s):  
Wentong Gao ◽  
Qitong Wang ◽  
Xiaoming Zhu ◽  
Zhanfeng Liu ◽  
Na Li ◽  
...  
Keyword(s):  
Vertical Distribution ◽  
Distribution Pattern ◽  
Soil Depth ◽  
Dominant Role ◽  
Mineral Soil ◽  
Coniferous Forest ◽  
Organic C ◽  
Vertical Distribution Pattern ◽  
Picea Asperata ◽  
The Vertical Distribution

Abstract Background and aimsWhile the quantitative assessment of plant- and microbial-derived carbon (C) in the soil organic C (SOC) chemical composition in soil profiles has been initially explored, the vertical distribution pattern of these two C sources and their dominant role in SOC formation based on the insights related to the rhizosphere are still lacking.MethodsWe quantified the divergent accumulation of microbial-derived C (i.e., microbial residues), plant-derived C (i.e., lipids and lignin phenols) and SOC in the rhizosphere at various depths (0-10 cm, 10-20 cm and 20-30 cm) in the upper mineral soil and analyzed its control factors in an alpine coniferous forest (Picea asperata. Mast). We further revealed the relative contribution of plant- or microbial-derived C to rhizosphere SOC in the soil profile.ResultsThe contents of microbial- and plant-derived C and SOC in the rhizosphere decreased with soil depth and were mainly regulated by root and microbial biomass. Moreover, the contribution of microbial-derived C dominated by fungal residues to rhizosphere SOC at each soil depth (more than 62%) was much higher than that of plant-derived C (less than 6%), implying that the soil microbial C pump was intensely stimulated in the rhizosphere.ConclusionsThese results indicated that microbial-derived C was the main contributor of rhizosphere SOC at various depths in the upper mineral soil. Our findings provide direct experimental evidence for assessing the dominant contribution of microbial- or plant-derived C to SOC in the soil profile from the perspective of the rhizosphere.

Diverse taxa of zooplankton inhabit hypoxic waters during both day and night in a temperate eutrophic lake

2019 ◽  
Vol 41 (4) ◽  
pp. 431-447 ◽  
Author(s):  
Sean Nolan ◽  
Stephen M Bollens ◽  
Gretchen Rollwagen-Bollens
Keyword(s):  
Dissolved Oxygen ◽  
Vertical Distribution ◽  
Food Web ◽  
Vertical Migration ◽  
Diel Vertical Migration ◽  
Eutrophic Lake ◽  
Water Bodies ◽  
Marine Waters ◽  
The Common ◽  
The Vertical Distribution

Abstract As the frequency and intensity of hypoxic events increase in both fresh and marine waters, understanding the ecological effects of hypoxia becomes more important. The extant literature reports varying effects of hypolimnetic hypoxia on the vertical distribution and diel vertical migration (DVM) of zooplankton, with some but not all taxa reported to avoid hypoxic waters. We studied the vertical distribution and DVM of diverse zooplankton taxa throughout three seasons over 2 years (2014 and 2015) in Lacamas Lake, WA, USA. We observed hypoxia (<2 mg L−1 dissolved oxygen) in the hypolimnion of Lacamas Lake during five of six sampling periods, with zooplankton populations often exhibiting ‘h-metric’ values (defined as the proportion of a zooplankton population residing within hypoxic waters) ranged from 0.14 to 1.00, with an overall mean of h = 0.66. Moreover, we observed a lack of DVM in most zooplankton taxa on most occasions. Our findings indicate both community-level and taxon-specific zooplankton tolerances to hypoxia, although the exact mechanisms at play remain to be fully elucidated. Nevertheless, the common residency in hypoxic waters and the lack of DVM by diverse zooplankton taxa that we observed likely have implications for food web dynamics in Lacamas Lake and other water bodies.

scholarly journals Seasonal differences in the vertical distribution pattern of Japanese jack mackerel, Trachurus japonicus: changes according to age?

2009 ◽  
Vol 66 (6) ◽  
pp. 1289-1295 ◽  
Author(s):  
Takeshi Nakamura ◽  
Akira Hamano
Keyword(s):  
Vertical Distribution ◽  
Distribution Pattern ◽  
Artificial Reefs ◽  
Clear Understanding ◽  
Jack Mackerel ◽  
Seasonal Differences ◽  
Vertical Distribution Pattern ◽  
Trachurus Japonicus ◽  
Japanese Jack Mackerel ◽  
The Vertical Distribution

Abstract Nakamura, T., and Hamano, A. 2009. Seasonal differences in the vertical distribution pattern of Japanese jack mackerel, Trachurus japonicus: changes according to age? – ICES Journal of Marine Science, 66: 1289–1295. The Japanese jack mackerel, Trachurus japonicus, is commercially and ecologically one of the most important fishery resources in Japanese waters. A clear understanding of the age-dependent, vertical distribution pattern is important for the effective and sustainable management of this resource. In this study, acoustic surveys were conducted from June to November 2001 in the western Sea of Japan to clarify seasonal differences. The survey area included a number of artificial reefs at depths >100 m. To identify fish species and determine the characteristics of the water column, simultaneous biological sampling and oceanographic surveys were carried out. The vertical distribution of Japanese jack mackerel varied with their age and size and between seasons. In June and July, aggregations of juvenile (age 0; <10 cm in length) Japanese jack mackerel were found in a layer between 20 and 50 m deep associated with a temperature range of 19–21°C. However, the age-0 aggregations were not observed from August to November. Conversely, the age-1+ schools aggregated around the artificial reefs when the temperature was <19°C. It is suggested that there are seasonal differences in the vertical distribution pattern between the early life and adult stages of Japanese jack mackerel. Because of the different vertical distributions of these life stages, acoustic backscatter information is useful for determining the age of the observed fish.

scholarly journals Differences in the Vertical Distribution of Two Cladoceran Species in the Nakdong River Estuary, South Korea

Water ◽  
2020 ◽  
Vol 12 (8) ◽  
pp. 2154
Author(s):  
Seong-Ki Kim ◽  
Jong-Yun Choi
Keyword(s):  
Vertical Distribution ◽  
River Estuary ◽  
Bottom Layer ◽  
Cycle Phase ◽  
Nakdong River ◽  
Fish Predator ◽  
Cladoceran Species ◽  
Vertical Distributions ◽  
The Nakdong River ◽  
The Vertical Distribution

As cladocerans are a primary food source for fish, predator avoidance is important to sustain cladoceran populations. We hypothesized that Bosmina longirostris and Daphniaobtusa would show different vertical distributions that depend on environmental variables and their life cycle phase. Quarterly monitoring was implemented in three water column layers (upper, middle, and bottom) in the Nakdong River Estuary. Cladocerans were mostly observed during summer; B. longirostris and D.obtusa were most abundant and exhibited different vertical distributions. Large (>600 μm) D.obtusa individuals were mainly distributed in the bottom layer (9–11 m) during the daytime and in the upper layer (1–3 m) at night. Utilization of the bottom layer by large D. obtusa was possibly a defense strategy to avoid fish predation. Although the bottom layer was not supported by lower water temperatures and dissolved oxygen than the upper or middle layers, as suggested in the previous study, we assumed that high turbidity replaced this role as a place shunned by fish (and thus a refuge for Daphnia obtusa). In contrast, smaller individuals remained in the upper layer at all times because of the low predation risk. The consumption of B. longirostris by fish was low, as the largest B. longirostris (411 μm) was smaller than the small-sized Daphnia. From this finding, we suggest that the vertical distribution of cladocerans likely depends on selectivity feeding based on fish size rather than the presence/absence of fish. We considered that these results are an important advance in understanding distribution patterns of cladocerans related to environmental features, as well as their key predators.

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