Aquatic Sciences Meeting, Albuquerque 2001
| SS24 The Ecology of Pelagic Gelatinous Zooplankton |
| Date: Monday, February 12, 2001, Time: 4:15:00 PM |
| Location: Acoma/Zuni/Tesuque |
| Tiselius, P, , Goteborg University, Dept of Marine Ecology, Kristineberg Marine Research Station, Fiskebacckskil, Sweden, p.tiselius@kmf.gu.se |
| Maar, M, , National Environmental Research Institute, Roskilde, Denmark, mam@dmu.dk |
| Zervoudaki, T, , National Centre for Marine Research, Athens, Greece, tanya@fl.ncmr.gr |
| Tonnesson, K, , Goteborg University, Dept of Marine Ecology, Kristineberg Marine Research Station, Fiskebackskil, Sweden, k.tonnesson@kmf.gu.se |
| Gooding, S, , National Environmental Research Institute, Roskilde, Denmark, |
| Christou, E, , National Centre for Marine Research, Athens, Greece, edc@fl.ncmr.gr |
| Sell, A, , Goteborg University, Dept of Marince Ecology, Kristineberg Marine Research Station, Fiskebackskil, Sweden, a.sell@kmf.gu.se |
| Vargas, C, , Universidad de Concepcion, Concepcion, Chile, crvargas@udec.cl |
| Petersen, J, K, National Environmental Research Institute, Roskilde, Denmark, jkp@dmu.dk |
| Nielsen, T, G, National Environmental Research Institute, Roskilde, Denmark, tgn@dmu.dk |
| FUNCTIONAL RESPONSE OF THE APPENDICULARIAN OIKOPLEURA DIOICA. |
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| The presence of regulating mechanisms for the food intake of O.dioica is controversial. Since particles are captured both by the animal and through adhesion to its house, interpretation of a functional response is difficult. In the present study we exposed O.dioica to a wide range of concentrations (0-1600 µgC/L) of Isochrysis. Clearance rate decreased at concentrations >80 µgC/l characteristic of a Type-II response. Maximum pellet production (7-10 pellets/ind/h) occurred at similar food levels (100 µgC/l) and higher concentrations resulted in lower pellet production. House production was constant (3-5 houses/ind/d). The hyperbolic shape shows that O.dioica can regulate its filtration rate at higher concentrations. This will reduce clogging, but the hyperbolic shape of the functional response is not consistent with clogging as a cause for reduced intake. The discrepancy between ingestion and pellet production is due to clogging, but the animal actively reduce filtration to avoid critical clogging. By this mechanism, O.dioica is able to tolerate higher than optimal food concentrations; ingestion rates are high enough to allow survival but low enough to prevent destruction of the food collecting filters. |
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