Food chain effects of nutrient limitation in primary producers

Abstract

The propagation of mineral limitation in primary producers to the second consumer level has rarely been investigated. Recently, it has been shown that limitation effects do travel up the food chain, not only quantitatively, but also qualitatively, and also that these quality effects affect the nutritional condition and growth of secondary consumers. The present study experimentally investigated the effect of phosphorus limitation in combination with fatty acid addition in primary producers (Scenedesmus obliquus) channelled through a primary consumer (Daphnia magna) on the condition of larval rainbow trout (Oncorhynchus mykiss). The C: P ratio and the fatty acid concentrations of the primary producers varied significantly with the phosphorus concentration of the culture media. These differences were also visible in the primary consumers (D. magna) feeding on the algae. The significantly different stoichiometry and fatty acid concentrations of the daphnids fed to larval trout did not lead to significant differences in growth, but the additional supplementation of fatty acid emulsions caused a significant increase in the condition of the fish. It was found that in the case of Daphnia as the primary prey for fish, with its relatively high phosphorus content even under phosphorus limitation, it is unlikely that phosphorus limitation affects fish condition and growth

Different tolerances of jellyfish ephyrae (Aurelia sp. 1) and fish larvae (Paralichthys olivaceus) to nutrient limitations

“…FA content) (Sterner & Elser 2002). In our experiments, the rotifers in the P-limited treatment produced significantly higher FA contents than those in the other treatments, and similar phenomena have been reported in other organisms under nutrient-limited conditions, exhibiting higher FA content (Boersma 2000, Klausmeier et al 2004a, Malzahn et al 2007, Boersma et al 2009). Siron et al (1989) stated that the enhanced FA contents exhibited in P-limited treatments could be attributed to C storage in re sponse to an imbalanced nutrient supply (suboptimal growth condition).…”

“…The ionic strength in the nutrient-limited treatments was maintained by the addition of KCl. Therefore, the algae of the 2 limitation treatments could only utilize the natural P or N sources present in the seawater, with the other nutrient added in excess, ensuring that the desired nutrient was limiting (Boersma et al 2009, Schoo et al 2014. Preliminary tests showed that nutrient composition (% of dry mass [DM]: %C, %N, and %P) and molar ratios (C:N, C:P, and N:P) of C. vulgaris (Table 1) changed significantly (all p < 0.05; Table 1) under the experimental conditions after a growth period of 5 d. Algae grown under the N-limited condition showed a lower value of N:P than the Full treatment (11.49 for −N and 27.54 for −F; Table 1), whereas the P-limited algae showed a higher value of N:P (71.58 for −P; Table 1).…”

Long-term change in the copepod community in the southern German Bight

“…These potentially have implications for the recruitment of predators of the zooplankton. Not only have the densities of important prey items decreased, but most likely as a result of the changes in nutrient conditions of the zooplankton also its quality as food for higher trophic levels (Boersma et al, , 2009Malzahn et al, 2007). In fact, Fig.…”

Increased carbon dioxide availability alters phytoplankton stoichiometry and affects carbon cycling and growth of a marine planktonic herbivore

“…These changes in carbon availability to the marine system are likely to have other potentially far-reaching impacts on the functioning of predator-prey interactions and may therefore affect the whole of the marine food web. Changes in food quality at the base of the food web affect primary consumers and thus propagate through the food web with potentially strong negative effects on the fitness and potentially the recruitment of higher trophic levels (Boersma et al 2009;Malzahn et al 2010;Schoo et al 2010Schoo et al , 2012. Higher availability of carbon and the subsequent changes in seawater nutrient composition, caused by the relatively lower availability of mineral nutrients compared to C, may also cause shifts in competitive interactions between algae (e.g.…”