Zooplankton grazing and growth: Scaling within the 2‐2,‐μm body size range

Abstract

In order to study the size dependency of grazing and growth rates in zooplankton, data wcrc collected from laboratory studies in the literature, covering both limnic and marinc organisms. Data were obtained from about 60 species of nano-, micro-, and mesozooplankton, representing flagellates, ciliates, rotifers, meroplankton larvae, copepods, and cladocerans. Estimates of maximum ingestion and clearance were extracted from functional responses (ingestion rates as a function of food density) cstablishcd from laboratory experiments. Maximum specific rates were expressed as a function of predator body volume. Maximum specific clearance and ingestion rates decreased with predator volume within each group of zooplankton, with a-common exponent (scaling factor) of -0.23 (SE = 20.12) in accordance with previous findings. However, significant differences wcrc found between groups. In particular, among the protists, ciliates display maximum ingestion, growth, and clearance rates that exceed those of dinoflagellates by a factor of 2-4. Among the metazooplankton, Calanoid copepods have maximum clearance rates that cxcccd those of filter-feeding cladocerans and meroplankton larvae by a factor of 10. Because of these differenccs between the groups, the entire set of observations could not be fitted by an overall regression.

Universal temperature and body-mass scaling of feeding rates

“…We found a variety of exponents for the relationship between handling time and resource mass ranging from zero to unity. Traditionally, assuming two resource items each of 1 g will take the same time to handle as one resource of 2 g led to linear scaling models in functional response studies and theoretical models [19,20,22,23,34]. However, assuming digestion processes to be dependent (i) on the degree the resource is broken down into pieces or (ii) that digestion takes place only on the surface of the resource item, this relationship can be dampened.…”

“…Classically, many bioenergetic models [19,20,22,23] and older functional response studies [34] assumed that resource mass is linearly proportional to digestion time leading to an isometric scaling. However, there is a more complex interplay between the degree to which time is devoted to ingestion and the subsequent digestion of the resulting resource pieces [32].…”

“…The attack rate is the rate of successful attacks (also termed capture rate [33], instantaneous rate of successful search [31], maximum filtration rate [34] or maximum interaction strength [4]) and includes processes such as searching (e.g. movement), detection, encounter and success of the attack [27].…”

Evolving ecological networks and the emergence of biodiversity patterns across temperature gradients

“…Our key assumption is that biological rates scale with metabolic rate [15][16][17][28][29][30][31]. We further assume that nutrients are made available through temperature-dependent biological or chemical processes.…”

“…Ectotherm metabolism is governed primarily by temperature and body size [10]. Thus, via metabolism, temperature and size can influence basal resource supply and trophic interactions (ecological processes) [11][12][13], individual resource use for survival and reproduction (organismal processes) [14][15][16][17], and the production of genetic variation and phenotypic divergence (evolutionary processes) [18][19][20][21][22]. Previous theory only accounts for subsets of these metabolic dependencies and does not incorporate feedbacks among key factors underlying ecological, organismal and evolutionary dynamics.…”