Does the nutrient stoichiometry of primary producers affect the secondary consumer Pleurobrachia pileus?
Schoo, K.L.; Aberle, N.; Malzahn, A.M.; Boersma, M. (2010). Does the nutrient stoichiometry of primary producers affect the secondary consumer Pleurobrachia pileus? Aquat. Ecol. 44(1): 233-242. http://dx.doi.org/10.1007/s10452-009-9265-4
In: Aquatic Ecology. Springer: Dordrecht; London; Boston. ISSN 1386-2588; e-ISSN 1573-5125, more
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Phosphorus limitation; Ctenophores; Ecological stoichiometry; Marinefood webs; Gelatinous zooplankton; Trophic transfer |
| Authors | | Top |
- Schoo, K.L.
- Aberle, N.
- Malzahn, A.M.
- Boersma, M.
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| Abstract |
We investigated whether phosphorus limitations of primary producers propagate upwards through the food web, not only to the primary consumer level but also onto the secondary consumers' level. A tri-trophic food chain was used to assess the effects of phosphorus-limited phytoplankton (the cryptophyte Rhodomonas salina) on herbivorous zooplankters (the copepod Acartia tonsa) and finally on zooplanktivores (the ctenophore Pleurobrachia pileus). The algae were cultured in phosphorus-replete and phosphorus-limited media before being fed to two groups of copepods. The copepods in turn were fed to the top predator, P. pileus, in a mixture resulting in a phosphorus-gradient, ranging from copepods having received only phosphorus-replete algae to copepods reared solely on phosphorus-limited algae. The C:P ratio of the algae varied significantly between the two treatments, resulting in higher C:P ratios for those copepods feeding on phosphorus-limited algae, albeit with a significance of 0.07. The differences in the feeding environment of the copepods could be followed to Pleurobrachia pileus. Contrary to our expectations, we found that phosphorus-limited copepods represented a higher quality food source for P. pileus, as shown by the better condition (expressed as nucleic acid content) of the ctenophore. This could possibly be explained by the rather high C:P ratios of ctenophores, their resulting low phosphorus demand and relative insensitivity to P deficiency. This might potentially be an additional explanation for the observed increasing abundances of gelatinous zooplankton in our increasingly phosphorus-limited coastal seas. |
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