Predation on Ciliates by the Suspension-Feeding Calanoid Copepod Acanthodiaptomus denticornis

1993 ◽  
Vol 50 (7) ◽  
pp. 1382-1393 ◽  
Author(s):  
Hans J. Hartmann ◽  
Hassan Taleb ◽  
Lotfi Aleya ◽  
Nicole Lair
Keyword(s):  
Calanoid Copepod ◽  
Prey Capture ◽  
Trophic Levels ◽  
Suspension Feeding ◽  
Clearance Rates ◽  
Cell Width ◽  
Astasia Longa ◽  
Stentor Coeruleus ◽  
Freshwater Copepods ◽  
Acanthodiaptomus Denticornis

The effects of prey size, hunger, and algal presence on the predation of the suspension-feeding calanoid copepod Acanthodiaptomus denticornis on the ciliates Tetrahymena corlisii (32 μm mean length), Paramecium aurelia (114 μm), P. caudatum (124 μm), Loxodes sp. [Formula: see text], and Stentor coeruleus[Formula: see text] and the flagellate Astasia longa (14 μm) were evaluated in laboratory experiments. Adult Acanthodiaptomus consumed all species, but not in proportion to their size. At low concentrations (prey < 200 μg C∙L−1), mean clearance rates ranged from 80 mL∙copepod−1∙d−1 (for Paramecium) to 13 mL∙copepod−1∙d−1 (for Loxodes). Clearance rates declined with increasing concentration of the same prey, as expected. Prey capture and ingestion was determined by cell width and prey escape reactivity. Hunger significantly increased predation rates at high prey levels. The presence of algae enhanced ciliate predation by hungry copepods at low prey levels, but had no other significant effects. Protozoan predation by Acanthodiaptomus generally exceeds its feeding on algae and nanoplankton. Results suggest that ciliates can be a significant part of the diet of some suspension-feeding freshwater copepods in situ, confirming the importance of ciliates as mediators of energy transfer from the microbial loop to higher trophic levels.

scholarly journals Volumetric quantification of fluid flow reveals fish's use of hydrodynamic stealth to capture evasive prey

2014 ◽  
Vol 11 (90) ◽  
pp. 20130880 ◽  
Author(s):  
Brad J. Gemmell ◽  
Deepak Adhikari ◽  
Ellen K. Longmire
Keyword(s):  
High Speed ◽  
Prey Capture ◽  
Fluid Motion ◽  
Three Dimensional ◽  
Trophic Levels ◽  
Small Fish ◽  
Major Pathway ◽  
Image Velocimetry ◽  
Highly Sensitive ◽  
Volumetric Quantification

In aquatic ecosystems, predation on zooplankton by fish provides a major pathway for the transfer of energy to higher trophic levels. Copepods are an abundant zooplankton group that sense hydromechanical disturbances produced by approaching predators and respond with rapid escapes. Despite this capability, fish capture copepods with high success. Previous studies have focused on the predatory strike to elucidate details of this interaction. However, these raptorial strikes and resulting suction are only effective at short range. Thus, small fish must closely approach highly sensitive prey without triggering an escape in order for a strike to be successful. We use a new method, high-speed, infrared, tomographic particle image velocimetry, to investigate three-dimensional fluid patterns around predator and prey during approaches. Our results show that at least one planktivorous fish ( Danio rerio ) can control the bow wave in front of the head during the approach and consumption of prey (copepod). This alters hydrodynamic profiles at the location of the copepod such that it is below the threshold required to elicit an escape response. We find this behaviour to be mediated by the generation of suction within the buccopharyngeal cavity, where the velocity into the mouth roughly matches the forward speed of the fish. These results provide insight into how animals modulate aspects of fluid motion around their bodies to overcome escape responses and enhance prey capture.

Stable carbon isotopic analysis of amino acids in a simplified food chain consisting of the green alga Chlorella spp., the calanoid copepod Calanus sinicus, and the Japanese anchovy (Engraulis japonicus)

2018 ◽  
Vol 96 (1) ◽  
pp. 23-30 ◽  
Author(s):  
Hai-zhen Liu ◽  
Lin Luo ◽  
De-ling Cai
Keyword(s):  
Amino Acids ◽  
Green Alga ◽  
Trophic Level ◽  
Food Chain ◽  
Calanoid Copepod ◽  
Trophic Levels ◽  
Japanese Anchovy ◽  
Calanus Sinicus ◽  
Engraulis Japonicus ◽  
Green Alga Chlorella

Japanese anchovy (Engraulis japonicus Temminck and Schlegel, 1846) is a keystone species in the food web of the Yellow Sea and East China Sea ecosystem. To study nutrient flow at intermediate and lower trophic levels, a controlled feeding experiment was carried out on a simplified food chain of the green alga Chlorella Beijerinck, 1890 – the calanoid copepod Calanus sinicus Brodsky, 1962 – E. japonicus. For the whole organism, bulk δ13C was found to be enriched with escalating trophic level, although the intertrophic gap in δ13C was slightly lower than the commonly reported 1.5‰ per increase in level. Furthermore, 15 amino acids (AAs) were detected in the studied organisms. Among them, the δ13C values of 12 AAs were determined and were found to exhibit diverse patterns of variation. The δ13C levels of essential AAs changed very little and were highly correlated across trophic levels, indicating that they underwent little trophic fractionation and were mainly ingested by the consumers from the proteins in their food. In contrast, the δ13C values of nonessential AAs differed greatly across trophic levels, indicating that the nonessential AAs in consumers were synthesized de novo from food proteins. The fractionation pattern of nonessential AAs may depend on the carbon pool and the AA composition of the organism at the lower trophic level.

A method for assessing clearance rates in suspension-feeding organisms by means of a fiber-optic colorimeter

1991 ◽  
Vol 69 (10) ◽  
pp. 2703-2706 ◽  
Author(s):  
Daniel J. Hornbach ◽  
Thomas Wilcox ◽  
John Layne ◽  
Lindsay Powers ◽  
Timothy Davis
Keyword(s):  
Direct Measurement ◽  
Continuous Monitoring ◽  
Fiber Optic ◽  
Suspension Feeding ◽  
Light Path ◽  
Fiber Optic Probe ◽  
Clearance Rates ◽  
Path Lengths ◽  
Optic Probe

A method for determining the clearance rates of suspension-feeding organisms by means of a fiber-optic colorimeter is discussed. The fiber-optic probe facilitates direct measurement of the turbidity of solutions without the need for removing subsamples. This allows for continuous monitoring and overcomes problems associated with calculating clearance rates if subsamples are removed. Standard curves are provided for plastic microspheres of six sizes (0.497–45.8 μm diameter), at concentrations of 0.8–100 mg/L, for each of four light-path lengths (1, 2, 5, and 10 cm). An experiment using the freshwater unionid mussel Truncilla truncata is described as an example of the use of this method.

Carnivorous Suspension Feeding by the Subarctic Calanoid Copepod Neocalanus cristatus

1988 ◽  
Vol 45 (6) ◽  
pp. 1069-1074 ◽  
Author(s):  
Charles H. Greene ◽  
Michael R. Landry
Keyword(s):  
Calanoid Copepod ◽  
Prey Size ◽  
Prey Selection ◽  
Suspension Feeding ◽  
Calanoid Copepods ◽  
Pelagic Ecosystem ◽  
Foraging Mode ◽  
Feeding Experiments ◽  
Feeding Modes

Carnivorous suspension feeding is described for the large subarctic calanoid copepod Neocalanus cristatus. This foraging mode relies on the use of a feeding current to entrain potential prey items and transport them into the copepod's capture area. The extensive use of a feeding current to entrain and transport prey into the capture area distinguishes carnivorous suspension feeding from the predatory modes typically described for other calanoid copepods. The consequences of carnivorous suspension feeding on N. cristatus' prey-selection patterns are significant. Feeding experiments reveal that the vulnerability of naupliar prey declines with increasing prey size, just the opposite result observed for other marine calanoids exhibiting more typical predatory feeding modes. The role of omnivorous feeding by N. cristatus within the pelagic ecosystem of the subarctic Pacific is also discussed. In contrast with earlier hypotheses, the results reported here are consistent with the emerging view that this large suspension-feeding copepod may be having at least as great an impact on the microzooplankton as on the phytoplankton of the region.

scholarly journals Copepod species abundance from the Southern Ocean and other regions (1980–2005) – a legacy

2018 ◽  
Author(s):  
Astrid Cornils ◽  
Rainer Sieger ◽  
Elke Mizdalski ◽  
Stefanie Schumacher ◽  
Hannes Grobe ◽  
...  
Keyword(s):  
Southern Ocean ◽  
Calanoid Copepod ◽  
Species Abundance ◽  
Life Cycles ◽  
Weddell Sea ◽  
Trophic Levels ◽  
Copepod Species ◽  
Data Sets ◽  
Planktonic Copepods ◽  
Abundance And Distribution

Abstract. Copepods are often the predominant taxa in marine zooplankton and play an important role in the food web as intermediators between primary producers, the microbial loop and higher trophic levels. Due to their short life cycles and their rapid response to changing environments they are good indicators for ecosystem health and status. Investigating the effects of environmental change on planktonic copepods and thus the pelagic ecosystem requires data on species abundance and distribution. Here, we present 33 data sets with abundance and occurrence of planktonic copepods from 20 expeditions to the Southern Ocean (Weddell Sea, Scotia Sea, Amundsen Sea, Bellingshausen Sea, Antarctic Peninsula), one expedition to the Magellan region, one latitudinal transect in the Eastern Atlantic Ocean, one expedition to the Great Meteor Bank and one expedition to the northern Red Sea and Gulf of Aqaba. In this data compilation a total of 349 stations between 1985 and 2005 were archived. These data sets are now freely available at PANGAEA via the persistent identifier doi:10.1594/PANGAEA.884619. During most expeditions depth-stratified samples were taken with a Hydrobios multinet with 5 or 9 nets. On few occasions a Nansen or Bongo net was deployed. The deepest sample reached down to 2880 meter. As metadata sampling date and date/time, latitude, longitude, bottom depth, sampling depth interval, volume of filtered water and information of the net type and mesh size were recorded. Abundance and distribution data for 284 calanoid copepod species and 28 taxa of other copepod orders are provided. The taxonomic concept was consistent throughout the data sets. The density of calanoid copepod species was separately counted for females, males and copepodites. For selected species also the individual copepodite stages were counted.

scholarly journals Capture, ingestion, and egestion of microplastics by suspension-feeding bivalves: a 40-year history

2019 ◽  
Vol 2 (1) ◽  
pp. 39-49 ◽  
Author(s):  
J. Evan Ward ◽  
Maria Rosa ◽  
Sandra E. Shumway
Keyword(s):  
Trophic Levels ◽  
Internal Exposure ◽  
Aquatic Environments ◽  
Suspension Feeding ◽  
Bivalve Molluscs ◽  
Negative Effects ◽  
Current State ◽  
Particle Processing ◽  
Selection For ◽  
Erroneous Data

In aquatic environments, suspension-feeding bivalve molluscs are exposed to a manifold of natural and anthropogenically derived particles, including micro- and nanoplastics. Plastic particles interact with feeding and digestive organs and can produce negative effects. As a result of these effects and the potential transfer of microplastics to higher trophic levels, including humans, there has been renewed interest in the ingestion of plastic particles by different species of bivalves. Many recent studies, however, have ignored the ability of bivalves to select among particles both pre- and post-ingestively. Neglecting to consider the factors that mediate particle capture, ingestion, and egestion can lead to erroneous data and conclusions. This paper outlines the current state of knowledge of particle processing by bivalves, and demonstrates how it relates to studies utilizing plastic particles. In particular, the effects of particle size, shape, and surface properties on capture, preferential ingestion, post-ingestive sorting, and egestion are summarized. The implications of particle selection for the use of bivalves as bioindicators of microplastic pollution in the environment are discussed. Only through a full understanding of the types of plastic particles ingested and egested by bivalves can internal exposure, toxic effects, and trophic transfer of microplastics be assessed adequately.

The importance of microzooplankton versus phytoplankton to copepod populations during late winter and early spring in Lake Michigan

2005 ◽  
Vol 62 (10) ◽  
pp. 2371-2385 ◽  
Author(s):  
Marie H Bundy ◽  
Henry A Vanderploeg ◽  
Peter J Lavrentyev ◽  
Paul A Kovalcik
Keyword(s):  
Chlorophyll A ◽  
Lake Michigan ◽  
Calanoid Copepod ◽  
Early Spring ◽  
Trophic Levels ◽  
Total Carbon ◽  
Late Winter ◽  
Heterotrophic Flagellates ◽  
Ingestion Rates ◽  
Size Fractions

Feeding rates of the calanoid copepod Leptodiaptomus sicilis on natural assemblages of phytoplankton and microzooplankton were evaluated during late winter and early spring in Lake Michigan. Microzooplankton were the preferred food source for this copepod, and larger size fractions of phytoplankton were preferred to smaller size fractions. Ingestion rates of total chlorophyll a ranged from 2 to 14 ng·copepod–1·day–1, while ingestion rates of micro zoo plank ton biomass ranged from 0.04 to 0.15 µg C·copepod–1·day–1. In these experiments, microzooplankton carbon accounted for 22%–74% of the total carbon ingested. Clearance rates of microzooplankton carbon were positively related to the larger size fractions of chlorophyll a and to total suspended solids. Measured ingestion rates of microzooplankton and phyto plankton carbon suggest that calanoid copepod populations have the potential to control microzooplankton production in late winter and early spring, and even with an abundance of phytoplankton carbon, food availability may limit the reproduction of L. sicilis. Because microzooplankton contribute significantly to the diet of these copepods, stimulation of the microbial food web by terrigenous inputs of nutrients and carbon may be transmitted to higher trophic levels (i.e., mesozooplankton and their predators) through heterotrophic flagellates and protozoans.

scholarly journals Growth, health and biochemical composition of the sea cucumber Cucumaria frondosa after multi-year holding in effluent waters of land-based salmon culture

2020 ◽  
Vol 12 ◽  
pp. 139-151 ◽  
Author(s):  
J Sun ◽  
JF Hamel ◽  
BL Gianasi ◽  
M Graham ◽  
A Mercier
Keyword(s):  
Biochemical Composition ◽  
Trophic Levels ◽  
Phospholipid Content ◽  
Suspension Feeding ◽  
Environmental Footprint ◽  
Effluent Water ◽  
Sea Cucumbers ◽  
Triacylglycerol Content ◽  
Cucumaria Frondosa ◽  
Growth And Reproduction

Methods have been proposed to mitigate the environmental footprint of aquaculture, including co-culture of species occupying different trophic levels. In this study, sea cucumbers Cucumaria frondosa, either from production tanks fed with effluent water from land-based salmon culture over 4 yr or collected from the field, were compared using stable isotope, lipid and fatty acid (FA) signatures as indicators of waste assimilation, health and biochemical composition. Enrichment of δ13C in muscle bands and intestine and of δ15N in muscle bands, gonad and intestine was detected in captive individuals relative to wild individuals, suggesting the uptake and assimilation of waste from salmon culture. The higher levels of FA biomarkers typical of salmon feed (18:1ω9, 18:2ω6 and 20:1ω9) and lower ω3/ω6 ratio in the captive sea cucumbers were also in line with assimilation of the waste. However, male and female sea cucumbers from the co-culture became smaller with time, their organ indices were lower than those of wild individuals (e.g. poorly developed gonad), and their biochemical composition differed: triacylglycerol content was greater in wild individuals and phospholipid content was greater in captive individuals. Also, FA profiles of all tissues differed between the 2 groups, whereas total lipid in muscle bands and gonad remained similar. Overall, results support that co-culture with suspension-feeding sea cucumbers may help mitigate the salmon industry footprint. In turn, the biochemical composition of the sea cucumbers changed, and their reduced size and body indices suggest that this food source does not provide suitable nutrients to sustain growth and reproduction.

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