Estimating the grazing impact of marine micro-zooplankton

Landry, Michael R.; Hassett, R. P.

doi:10.1007/bf00397668

Cited by 1,112 publications

(1,053 citation statements)

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“…All values in the data set were provided as such in the reports. Methods included the dilution technique (Landry and Hassett 1982) and grazer evacuation rates (Kiorbe and Tiselius 1987) for phytoplanktonic communities and herbivore enclosure/exclosures for the rest of communities (Valentine and Heck 1991;Heck et al 2000). Some estimates of herbivory on macroalgae, seagrasses, and mangroves were based on the number and size of herbivore bites imprinted on thalli or leaf blades (Ogden 1990).…”

Section: Methodsmentioning

confidence: 99%

Variability and control of carbon consumption, export, and accumulation in marine communities

Cebrián

2002

Limnology & Oceanography

133

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Elucidating the extent and controls of the routes followed by primary production in marine communities (i.e., consumption by herbivores, decomposition, transportation of plant material beyond the community boundariesreferred to as export-or accumulation as biomass or detritus) is essential to understand how much and why they differ in their capacity to fuel secondary production, both within or out of the community, and in their role as sinks in the oceanic carbon budget. Here, using an extensive compilation of published reports, I compare the magnitude of these routes across and within a wide range of community types, including oceanic and coastal phytoplanktonic communities, benthic microalgal communities, coral reef algal beds, macroalgal beds, seagrass meadows, marshes, and mangroves. Furthermore, I examine whether the variability in the magnitude of these routes among and within types is associated with that in the magnitude of primary production. In general, different community types showed similar levels of consumption by herbivores and export, in spite of substantial within-type variability. On the contrary, substantial differences in detritus decomposition and accumulation were found among types: coral reef algal beds and benthic microalgal communities tended to show the highest and lowest levels of decomposition, respectively, whereas marshes and oceanic phytoplanktonic communities tended to show the largest and smallest levels of detritus accumulation. The results also identify primary production as a robust (i.e., applicable to a wide range of environmental conditions and communities) control of the variability in herbivory and decomposition among marine communities. The role of primary production as a control of export and detritus accumulation is generally minor and only restricted to coastal phytoplanktonic and benthic microalgal communities, for export, and marshes and mangroves for detritus accumulation.

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Section: Methodsmentioning

confidence: 99%

Variability and control of carbon consumption, export, and accumulation in marine communities

Cebrián

2002

Limnology & Oceanography

133

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“…To investigate the growth and mortality rate of microphytoplankton, dilution experiments were conducted (Landry and Hassett, 1982;Landry et al, 1995). All incubation bottles, tubes, and carboys were acid-rinsed first with 10 % HCl and then with distilled water.…”

Section: Dilution Experimentsmentioning

confidence: 99%

“…Thus, we could calculate the slope as the grazing mortality (m) and the intercept as the intrinsic phytoplankton growth rate (µ) (Landry and Hassett, 1982;Landry et al, 1995). The novel and additional calculation here is that, for each size class, we carried out linear regression of realized phytoplankton growth rates on four dilution treatments to estimate size-specific growth rate and grazing mortality (Fig.…”

Section: Calculation Of Size-specific Growth Rate and Grazing Mortalitymentioning

confidence: 99%

Scaling of growth rate and mortality with size and its consequence on size spectra of natural microphytoplankton assemblages in the East China Sea

et al. 2013

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Allometric scaling of body size versus growth rate and mortality has been suggested to be a universal macroecological pattern, as described by the metabolic theory of ecology (MTE). However, whether such scaling generally holds in natural assemblages remains debated. Here, we test the hypothesis that the size-specific growth rate and grazing mortality scale with the body size with an exponent of −1/4 after temperature correction, as MTE predicts. To do so, we couple a dilution experiment with the FlowCAM imaging system to obtain size-specific growth rates and grazing mortality of natural microphytoplankton assemblages in the East China Sea. This novel approach allows us to achieve highly resolved size-specific measurements that would be very difficult to obtain in traditional size-fractionated measurements using filters. Our results do not support the MTE prediction. On average, the size-specific growth rates and grazing mortality scale almost isometrically with body size (with scaling exponent ∼0.1). However, this finding contains high uncertainty, as the size-scaling exponent varies substantially among assemblages. The fact that size-scaling exponent varies among assemblages prompts us to further investigate how the variation of size-specific growth rate and grazing mortality can interact to determine the microphytoplankton size structure, described by normalized biomass size spectrum (NBSS), among assemblages. We test whether the variation of microphytoplankton NBSS slopes is determined by (1) differential grazing mortality of small versus large individuals, (2) differential growth rate of small versus large individuals, or (3) combinations of these scenarios. Our results indicate that the ratio of the grazing mortality of the large size category to that of the small size category best explains the variation of NBSS slopes across environments, suggesting that higher grazing mortality of large microphytoplankton may release the small phytoplankton from grazing, which in turn leads to a steeper NBSS slope. This study contributes to understanding the relative importance of bottom-up versus top-down control in shaping microphytoplankton size structure

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“…Este impacto es una medida de la presión de consumo que ejerce el zooplancton sobre el fitoplancton, y para su estimación es necesario conocer la abundancia del zooplancton que consume fitoplancton, la cantidad de material fitoplanctónico disponible en el ambiente que se cuantifica con base en la concentración de clorofila-a, y las tasas de ingestiones específicas (Morales et Aunque los copépodos no se alimentan exclusivamente de fitoplancton, junto con las salpas y los eufaúsidos, son considerados los organismos planctónicos que mayor impacto alimentario ejercen sobre el fitoplancton en el ambiente pelágico (Mauchline, 1998). Sin embargo, sus tasas de ingestión generalmente se relacionan con el tamaño del organismos, por lo que los trabajos de impacto alimentario en función del espectro de tamaño presenta ventajas comparativas sobre estudios a nivel de especie , toda vez que las diferentes fracciones de tamaño se alimentan de tamaños específicos de organismos fitoplanctónicos (Landry & Hassett, 1982 Tradicionalmente, se ha utilizado la fluorescencia intestinal (Mackas & Bohrer, 1976) como método indirecto para realizar la estimación de las tasas de ingestión in situ en diferentes especies de copépodos (Morales et al, 1990;Sautor et al, 2000;Tseng et al, 2008;Li et. al., 2013, Isla et al, 2015.…”

Section: Introductionunclassified

Impacto alimentario de los copépodos calanoideos en el Océano Pacífico colombiano

REVISTAS¹,

Giraldo²,

Velasco³

et al. 2018

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Grazing rate of copepods was evaluated in the oceanic province of the Colombian Pacific during September 2006. Gut pigment content was estimated by spectophotometry considering three size fraction: small (300-500 µm), medium (500-1000 µm) and big (> 1000 µm). In order to estimate the ingestion rate, an experimental gut evacuation rate of 0.702 h -1 was used. Feeding impact was calculated like a proportion of phytoplankton standing stock, projecting the total copepod consumption by size in relation to chlorophyll-a concentration in each station. Small copepods were most abundant than medium or big copepods (Kruskal-Wallis H=21.83; p=0.01). Although the ingestion rate of big copepods was higher than medium or small copepods (Kruskal-Wallis H=6.48; p= 0.04), no significant differences in the consumption rate were detected among sizes (Kruskal-Wallis H=3.07; p=0.21). The chlorophyll-a integrate (0-50 m) in the study zone was between 4.4 and 9.5 mg Clo-a m -2 , being estimated the grazing impact of the big copepod in 2.57 ± 0.80 %, medium 3.57 ± 1.89 % and small 12.06 ± 5.99%.Keywords: grazing, ingestion rate, chlorophyll, copepods, Pacific Ocean, Colombia. Impacto alimentario de los copépodos calanoideos en elOcéano Pacífico colombiano ResumenSe determinó el impacto alimentario de los copépodos en nueve estaciones localizadas en la Cuenca Pacífica Colombiana durante septiembre de 2006. El contenido de pigmentos entéricos, fue medido espectrofotométricamente en tres fracciones de tamaño: pequeño (300-500 µm), mediano (500-1000 µm) y grande (> 1000 µm); y se estimó la tasa de consumo considerando una tasa de evacuación de 0.702 h -1 que fue establecida previamente de manera experimental. Considerando la abundancia de cada fracción y la concentración de clorofila-a en cada estación, se cuantificó el impacto alimentario como un porcentaje de la biomasa fitoplanctónica disponible. Los copépodos de menor tamaño fueron significativamente más abundantes en la zona de estudio (Kruskal-Wallis H=21.83; p=0.01). Aunque la tasa de ingestión de los copépodos grandes fue significativamente mayor (Kruskal-Wallis H=6.48; p= 0.04), no se detectaron diferencias significativas entre las tasas de consumo de las tres fracciones de tamaño evaluadas (Kruskal-Wallis H=3.07; p=0.21). La clorofila-a integrada (0 -50 m) en la zona de estudio estuvo entre 4.4 a 9.5 mg Clo-a m -2 , siendo el impacto alimentario promedio de los copépodos grandes de 2.57 ± 0.80 %, medianos 3.57 ± 1.89 % y pequeños 12.06 ± 5.99%.

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Estimating the grazing impact of marine micro-zooplankton

Cited by 1,112 publications

References 14 publications

Variability and control of carbon consumption, export, and accumulation in marine communities

Variability and control of carbon consumption, export, and accumulation in marine communities

Scaling of growth rate and mortality with size and its consequence on size spectra of natural microphytoplankton assemblages in the East China Sea

Impacto alimentario de los copépodos calanoideos en el Océano Pacífico colombiano

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