| 1. |
- Faithfull, Carolyn L., 1982-, et al.
(författare)
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Copepod nauplii use phosphorus from bacteria, creating a short circuit in the microbial loop
- 2019
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Ingår i: Ecology Letters. - : John Wiley & Sons. - 1461-023X .- 1461-0248. ; 22:9, s. 1462-1471
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Tidskriftsartikel (refereegranskat)abstract
- In subtropical oceans phytoplankton carbon: phosphorus (C : P) ratios are high, and these ratios are predicted to increase further with rising ocean temperatures and stratification. Prey stoichiometry may pose a problem for copepod zooplankton nauplii, which have high phosphorus demands due to rapid growth. We hypothesised that nauplii meet this demand by consuming bacteria. Naupliar bacterial and phytoplankton carbon and phosphorus ingestion, assimilation and incorporation were traced using P-33 and C-14 radioisotopes. Bacterial carbon was incorporated four times less efficiently into biomass than phytoplankton carbon. In contrast, bacterial and phytoplankton phosphorus were incorporated at similar efficiencies, and bacteria could meet a substantial amount of naupliar phosphorus requirements. As parts of the ocean become more oligotrophic, bacteria could help sustain naupliar growth and survival under suboptimal stoichiometric conditions. Thus, nauplii may be a shortcut for phosphorus from the microbial loop to the classical food web.
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| 2. |
- Holmborn, Towe, 1979-, et al.
(författare)
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Genetic species identification and low genetic diversity in Pseudocalanus acuspes of the Baltic Sea
- 2011
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Ingår i: Journal of Plankton Research. - : Oxford University Press (OUP). - 0142-7873 .- 1464-3774. ; 33:3, s. 507-515
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Tidskriftsartikel (refereegranskat)abstract
- Calanoid copepods of the genus Pseudocalanus are key species in temperate-boreal marine pelagic ecosystems. Pseudocalanus species are difficult to distinguish morphologically and there is uncertainty regarding the species present in the Baltic Sea. In this study, we investigated the species composition of Pseudocalanus in the Baltic proper and the Gulf of Finland using a restriction fragment length polymorphism approach. Screening of 888 individuals from 13 different stations, sampled during various seasons on a total of 22 different occasions stretching from November 2006 until July 2008, confirmed that P. acuspes is the only Pseudocalanus species normally present in the Baltic Sea. Mitochondrial diversity is exceptionally low in Baltic Sea populations of P. acuspes, as only two cytochrome oxidase I haplotypes were observed in samples ranging from the Gulf of Finland in the north to the Arkona Basin in the south (83 individuals). This unusually low level of genetic diversity indicates that planktonic organisms may experience loss of genetic diversity in marginal Baltic Sea populations, despite large population sizes. Low genetic diversity may negatively impact the species' capacity for adaptation to environmental change.
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