Functional response of carbon absorption efficiency in the pelagic calanoid copepod <i>Acartia tonsa</i>

Thor, Peter; Wendt, Ida

doi:10.4319/lo.2010.55.4.1779

Cited by 30 publications

(24 citation statements)

References 49 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The importance of variable physiological efficiencies has been highlighted by previous studies (Mitra and Flynn , Fenton et al. ) and is also experimentally well documented (Schindler , Bohrer and Lampert , Thor and Wendt , Halvorson et al. ).…”

Section: Discussionmentioning

confidence: 75%

“…Hence, assimilation, net growth and gross growth efficiencies were highly variable. The importance of variable physiological efficiencies has been highlighted by previous studies Flynn 2007, Fenton et al 2010) and is also experimentally well documented (Schindler 1968, Bohrer and Lampert 1988, Thor and Wendt 2010. Nevertheless, prominent food web models applied in ecosystem management such as Ecopath and Ecosim (Christensen and Walters 2004) or the recently developed Madingley models (Purves et al 2013) do not account for variations in physiological efficiencies.…”

Section: Discussionmentioning

confidence: 99%

“…In order to quantify the effect of increased or decreased investments in nutrient assimilation, the dynamics of digestive processes have to be accounted for. Nutrient concentrations in ingested food packages decrease with time as food packages are exposed to digestive enzymes and nutrients are assimilated (Raubenheimer and Simpson , Thor and Wendt ). Hence, a long gut transition time results in the uptake of a higher percentage of available nutrients and increases assimilation efficiencies (Mitra and Flynn ).…”

Section: Theoretical Synthesismentioning

confidence: 99%

See 2 more Smart Citations

Food quantity–quality interactions and their impact on consumer behavior and trophic transfer

Burian

Nielsen

Winder

2019

Ecological Monographs

View full text Add to dashboard Cite

Food quantity–quality interactions determine growth rates and reproductive success of consumers and thereby regulate community dynamics and food web structure. Predator–prey models that shape our conceptual understanding of foraging ecology typically rely on the parametrization of fixed consumer responses to either food quantity or food quality. In nature, however, consumers optimize their fitness by responding simultaneously to changes in food quantity and quality. Therefore, we assessed consumer responses to changing food environments using a new fitness optimization model that accounted for food quality–quantity interactions to better capture the regulatory flexibility of consumers. Our simulations demonstrated that the impact of food quality on important consumer traits can be altered or even reversed by changes in food quality. Low food quality, for example, affected feeding rates negatively at low food concentrations but triggered surplus feeding at high food concentrations. The scope of surplus feeding was thereby mainly dependent on dynamics of nutrient digestion and in contrast to previous assumptions, energy costs of feeding played a minor role. Further, the regulation of digestive enzyme production, a crucial factor determining assimilation efficiencies, was strongly dependent on whether nonessential or essential nutrients were limiting growth. Consequently, not only the degree but also the type of nutrient limitation mediated the impact of the food environment on consumers’ fitness. At the community level, food quality was key in shaping predator–prey biomass ratios. High food qualities resulted in top‐heavy systems with larger consumer than prey biomass. Decreases of prey digestibility or the availability of essential nutrients, however, triggered a switch from inverted to classical pyramid shapes of bi‐trophic systems. The impact of food quantity on trophic transfer and emerging structural ecosystem properties thus critically hinges on behavioral and physiological responses of consumers. The inclusion of the regulatory flexibility of consumers is therefore an essential next step to improve predator–prey models and our conceptual understanding of trophic interactions.

show abstract

Section: Discussionmentioning

confidence: 75%

Section: Discussionmentioning

confidence: 99%

Section: Theoretical Synthesismentioning

confidence: 99%

See 1 more Smart Citation

Food quantity–quality interactions and their impact on consumer behavior and trophic transfer

Burian

Nielsen

Winder

2019

Ecological Monographs

View full text Add to dashboard Cite

show abstract

“…Literature data suggest that diatoms are more difficult to digest than flagellated microalgae (Conover 1966 as recalculated by Paffenhö fer and Kö ster 2005; Thor and Wendt 2010). One can speculate that the copepod gut produced more acidic fluid to aid the digestion of diatoms, although this is not necessarily related to the siliceous frustules because silica dissolution tends to occur faster in alkaline, not acidic, pH (Lewin 1961;Schlü ter and Rickert 1998), and biogenic silica is often used as inert tracer in copepod feeding studies (Tande and Slagstad 1985;Cowie and Hedges 1996).…”

Section: Discussionmentioning

confidence: 99%

Copepod guts as biogeochemical hotspots in the sea: Evidence from microelectrode profiling of Calanus spp

Tang¹,

Glud²,

Glud³

et al. 2011

Limnology & Oceanography

View full text Add to dashboard Cite

The environmental conditions inside the gut of Calanus hyperboreus and C. glacialis were measured with microelectrodes. An acidic potential hydrogen (pH) gradient was present in the gut of C. hyperboreus, and the lowest pH recorded was 5.40. The gut pH of a starved copepod decreased by 0.53 after the copepod resumed feeding for a few hours, indicating the secretion of acidic digestive fluid. A copepod feeding on Thalassiosira weissflogii (diatom) had slightly lower pH than that feeding on Rhodomonas salina (cryptophyte). Oxygen was undersaturated in the gut of both C. hyperboreus and C. glacialis, with a steep gradient from the anal opening to the metasome region. The central metasome region was completely anoxic. Food remains in the gut led to a lower oxygen level, and a diatom diet induced a stronger oxygen gradient than a cryptophyte diet. The acidic and suboxic-anoxic environments of the copepod gut may support iron dissolution and anaerobic microbial activities that otherwise are not favored in the well-buffered and oxygenated ambient ocean.

show abstract

“…Losses: Of the food ingested (g i ), 65% is assimilated (AE), while the rest is egested (Thor and Wendt 2010). Of the assimilated food, between 25% and 35% is assumed to be lost by active metabolism (R A ) depending on stage.…”

Section: Methodsmentioning

confidence: 99%

The effect of changes in temperature and food on the development of Calanus finmarchicus and Calanus helgolandicus populations

Møller

Maar

Jónasdóttir

et al. 2012

Limnology & Oceanography

View full text Add to dashboard Cite

We studied the response in development times of Calanus finmarchicus and Calanus helgolandicus to changes in temperature and food conditions. Grazing experiments were performed at different temperatures for both species, and the results were implemented in a stage-resolved zooplankton population model that predicted development times from biomass increments controlled by ingestion and metabolic losses. Predictions were validated against development data from the literature, and show that C. finmarchicus develops faster than C. helgolandicus below 11uC and slower above. The different relative development rates of the species are related to different temperature responses in ingestion rates. A temperature increase of 1uC to 2uC may have consequences for the relative contribution of C. helgolandicus and C. finmarchicus to the copepod community, and both seasonal and spatial displacements of the Calanus populations can be expected under climate change.

show abstract

Functional response of carbon absorption efficiency in the pelagic calanoid copepod Acartia tonsa

Cited by 30 publications

References 49 publications

Food quantity–quality interactions and their impact on consumer behavior and trophic transfer

Food quantity–quality interactions and their impact on consumer behavior and trophic transfer

Copepod guts as biogeochemical hotspots in the sea: Evidence from microelectrode profiling of Calanus spp

The effect of changes in temperature and food on the development of Calanus finmarchicus and Calanus helgolandicus populations

Contact Info

Product

Resources

About