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Infaunal benthic foraminifera: ecology, evolution and their role in the evolution of the global N-cycle
Project leader: Prof. dr. G. J. van der Zwaan
Researcher(s): Dr. K. A. Koho
Starting date: 1-apr-09

Abstract
The requested post-doc at UU will sample in close coordination with the postdoc attached to project 1 (see above) a large number of marine sediments. The aim is to collect a wide variety of living foraminifera from various environments. These foraminiferal species will be identified and analyzed separately for their ability to store nitrate internally and their denitrification rates. The origin of infaunal niches and how denitrification activity influences vertical migration of infaunal foraminifera will be analysed using both molecular as experimental techniques. During these experiments also macrofaunal-foraminiferal interactions will be studied. Extensive geochemical measurements will be performed and in order to manipulate geochemical zones, plug-flow-through reactors will be used. The effect of foraminiferal grazing on prokaryotes will be tested. The obtained results will give valuable information to incorporate in models dealing with the global N-cycle and will enable us to assess the potential impact on and contribution of foraminiferal denitrification to the marine and global N-cycle. In combination with the outcomes of project 1, the data will be connected to available data on foraminiferal phylogeny and appearance dates of taxa in the geological record. In this way, the (stepwise) evolution in time of the global N-cycle will be better constrained.

Publications
Piña-Ochoa E., Koho K.A., Geslin E., Risgaard-Petersen N. (2010). Survival and life strategy of the foraminiferan Globobulimina turgida through nitrate storage and denitrification. Marine Ecology Progress Series417: 39-49.
Darwin Center authors: Koho K. A.

Gooday A.J., Da Silva A.A., Koho K.A., Lecroq B., Pearce R.B. (2010). The 'mica sandwich'; a remarkable new genus of foraminifera (Protista, Rhizaria) from the Nazaré Canyon (Portuguese margin, NE Atlantic). Micropaleontology56: 345-357.
Darwin Center authors: Koho K. A.

Koho K.A., Piña-Ochoa E., Geslin E. and Risgaard-Petersen N. (2011). Vertical migration, nitrate uptake and denitrification: survival mechanisms of foraminifers (Globobulimina turgida) in low oxygen conditions. FEMS Microbiol Ecol75: 273-283.
Darwin Center authors: Koho K. A.