Disentangling food quantity and quality effects in zooplankton response to P‐enrichment and UV radiation

Abstract

In a 32-yr record in oligotrophic Lake La Caldera (Sierra Nevada, Spain) biomass of zooplankton was strongly correlated with precipitation, aerosol deposition intensity, and ultraviolet radiation (UVR). The food associatedeffects of these factors for zooplankton growth were tested in field-laboratory experiments with the aim of separating the effects of food quantity from those of food quality at low food conditions, where there is good evidence to support the existence of food quality effects. Manipulation of nutrients generated a large food quantity gradient that exerted the strongest effect on zooplankton growth, with no significant role of UVR. Growth curves were fitted to a saturation function that reached a plateau at increasing seston levels of ca. 250, 500, and 1000 mg C L 21 for the rotifer Keratella cochlearis, the copepod Mixodiaptomus laciniatus, and the cladoceran Daphnia pulicaria, respectively, and after which growth decreased in M. laciniatus. Nutrients and to a lesser extent UVR also affected seston quality, which had a minor effect on zooplankton growth. K. cochlearis growth was strongly related to the P content of seston, whereas M. laciniatus and D. pulicaria growth were positively correlated with a P-normalized v3-polyunsaturated fatty acid index (v3-PUFA:P). The increase in seston associated with more intense and frequent atmospheric depositions would adversely affect copepods, but improve growth of C-limited cladocerans and P-limited rotifers in pristine ecosystems of the Mediterranean region.

Shifts in food quality for herbivorous consumer growth: multiple golden means in the life history

“…copepods would not be expected to respond to the P and N content of the seston. However, copepods showed strong growth response to food P content at low food quantity, consistent with recent observations of a strong relationship between Mixodiaptomus laciniatus growth and seston P content in this ultraoligotrophic lake (Villar-Argaiz et al 2012). If copepods with complex life cycles and high C:N:P ratios suffer growth penalties due Table 4 and Results section for statistical results.…”

UVB Radiation Affects Growth, Reproduction and Tissue Structure of Daphnia magna Across Several Temperatures

“…Numerous studies have shown that temperature in combination with other environmental variables can affect zooplankton populations ( e.g. 4,20–22). Other studies have examined the interaction of temperature and UVR (8,9,23).…”

Water Stratification Affects the Microeukaryotic Community in a Subtropical Deep Reservoir

“…), which provide most of the high quality food for herbivore growth and this may contribut to the surface blooms of copepoda and rotifera (Villar‐Argaiz et al. ). In addition, some highly adaptable or opportunistic consumers (ciliophora) can grow in both layers because of its stronger ability of movement and applicability (Pfister et al.…”

“…Copepoda and rotifera had a cosmopolitan distribution in freshwater where they feed on small fragments of plant material, phytoplankton or carrion (Miracle 1982;Boothroyd et al 2002). The surface water is rich in productive primary producer and microplankton (Iriarte et al 2000;Schelske et al 2003), which provide most of the high quality food for herbivore growth and this may contribut to the surface blooms of copepoda and rotifera (Villar-Argaiz et al 2012). In addition, some highly adaptable or opportunistic consumers (ciliophora) can grow in both layers because of its stronger ability of movement and applicability (Pfister et al 2002).…”