• DOI:10.5194/BG-2016-509
• Corpus ID: 55626468

Effect of increased temperature on carbon and nitrogen uptake oftwo intertidal foraminifera ( Ammonia tepida and Haynesinagermanica )

@article{Wukovits2016EffectOI,
  title={Effect of increased temperature on carbon and nitrogen uptake oftwo intertidal foraminifera ( Ammonia tepida and Haynesinagermanica )},
  author={Julia Wukovits and Annekatrin Julie Enge and Wolfgang Wanek and Margarete Watzka and Petra Heinz},
  journal={Biogeosciences Discussions},
  year={2016},
  pages={1-25}
}

• J. Wukovits, A. Enge, +2 authors P. Heinz
• Published 28 November 2016
• Environmental Science
• Biogeosciences Discussions

Benthic foraminifera are highly abundant heterotrophic protists in marine sediments, but intertidal communities are expected to undergo future changes. Environmental changes can exceed the tolerance limits of intertidal species causing a shift in species composition which might result in altered nutrient fluxes. Factors limiting the abundance of specific foraminiferal species can be temperature related stress tolerance or food source processing efficiency. In this study, we performed a laboratory feeding experiment on Ammonia tepida and Haynesina germanica, two dominant foraminiferal species of the German Wadden 5 Sea/Friedrichskoog, to test the effect of temperature on phytodetritus ingestion. The specimens were fed with 13C and 15N labelled freeze dried Dunaliella tertiolecta (green algae) at the start of the experiment and were incubated at 20◦C, 25◦C, and 30◦C respectively. Dual labelling was applied to observe potential temperature effects on the relation of phytodetrital carbon and nitrogen retention. Samples were taken over a period of two weeks. Foraminiferal cytoplasm was isotopically analysed to investigate differences in carbon and nitrogen uptake derived from the food source. Both species showed a positive response 10 to the provided food source, but carbon uptake rates of A. tepida were 10-fold higher compared to those of H. germanica. Increased temperatures had a far stronger impact on carbon uptake of H. germanica than on A. tepida. A distinct increase in levels of phytodetrital derived nitrogen (compared to more steady carbon levels) could be observed over the course of the experiment. The results suggest that higher temperatures have a significant negative effect on the carbon exploitation of H. germanica. For A. tepida, higher carbon uptake rates and the enhanced tolerance range for higher temperatures could outline 15 an advantage in warmer periods, if the main food source consists of chlorophyte phytodetritus. These conditions are likely to impact nutrient fluxes in A. tepida/H. germanica associations.