IADO   05364
INSTITUTO ARGENTINO DE OCEANOGRAFIA
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Contribution of planktonic and detritical fractions to the natural diet of mesozooplankton in late spring.
Autor/es:
DIODATO, S. L.; HOFFMEYER, M. S.
Lugar:
Joao Pessoa, Brasil
Reunión:
Simposio; Plankton Symposium IV & Congresso Brasileiro de Plâncton; 2007
Institución organizadora:
AfPR- A for Plankton Research
Resumen:
CONTRIBUTION OF PLANKTONIC AND DETRITICAL FRACTIONS TO THE NATURAL DIET OF MESOZOOPLANKTON IN LATE SPRING Soledad Lorena Diodato & M¨®nica Susana Hoffmeyer Instituto Argentino de Oceanograf¨ªa (CONICET-UNS). Camino La Carrindanga Km 7,5, B8000FWB, Bah¨ªa Blanca, Argentina Corresponding author: Soledad Lorena Diodato, email: sole22diodato@yahoo.com.arsole22diodato@yahoo.com.ar ABSTRACT The relative importance of phytoplankton and microzooplankton in the natural diet of mesozooplankton was assessed in Bah¨ªa Blanca Estuary, Argentina, in December 2005. Grazing experiments were performed using 200 to 2,000 ¦Ìm grazers and natural food <100 ¦Ìm. Individual and community filtration and ingestion rates were estimated for each food fraction after 24 h incubation. Preys and grazers were qualitatively and quantitatively analyzed yielding results in abundance and carbon terms. Phytoplankton was mainly composed of diatoms whereas microzooplankton was mainly composed of tintinnids. Both fractions were less abundant than detritus. Most of the grazers belonged to the copepod Acartia tonsa. Mean filtration and ingestion rates on phytoplankton + microzooplankton were 6.44 mL grazer-1 d-1 and 0.03 ¦Ìg C.grazer-1.d-1, respectively. Including detritus, they increased to 6.954 mL.grazer-1.d-1 and 1.501 ¦Ìg C.grazer-1.d-1. Mean weight-specific ingestion rates upon phytoplankton and microzooplankton were 0.0059 and 0.0049 ¦Ìg C.¦Ìg C-1.d-1, respectively, whereas after the addition of detritus, the overall rate increased to 0.536 ¦Ìg C ¦Ìg.C-1.d-1. Highly significant differences were found between grazing rates on detritus and planktonic fractions. Consumers showed higher filtration rates on microzooplankton than on phytoplankton although 78% of the cells ingested (54.7% ¦Ìg C) came from the latter. Results seem to evidence a higher contribution of detritus to the natural diet of mesozooplankton in late spring. The omnivory of A. tonsa and the high turbidity of Bah¨ªa Blanca estuary may explain the differences observed in carbon intake among food fractions.Acartia tonsa. Mean filtration and ingestion rates on phytoplankton + microzooplankton were 6.44 mL grazer-1 d-1 and 0.03 ¦Ìg C.grazer-1.d-1, respectively. Including detritus, they increased to 6.954 mL.grazer-1.d-1 and 1.501 ¦Ìg C.grazer-1.d-1. Mean weight-specific ingestion rates upon phytoplankton and microzooplankton were 0.0059 and 0.0049 ¦Ìg C.¦Ìg C-1.d-1, respectively, whereas after the addition of detritus, the overall rate increased to 0.536 ¦Ìg C ¦Ìg.C-1.d-1. Highly significant differences were found between grazing rates on detritus and planktonic fractions. Consumers showed higher filtration rates on microzooplankton than on phytoplankton although 78% of the cells ingested (54.7% ¦Ìg C) came from the latter. Results seem to evidence a higher contribution of detritus to the natural diet of mesozooplankton in late spring. The omnivory of A. tonsa and the high turbidity of Bah¨ªa Blanca estuary may explain the differences observed in carbon intake among food fractions.-1 d-1 and 0.03 ¦Ìg C.grazer-1.d-1, respectively. Including detritus, they increased to 6.954 mL.grazer-1.d-1 and 1.501 ¦Ìg C.grazer-1.d-1. Mean weight-specific ingestion rates upon phytoplankton and microzooplankton were 0.0059 and 0.0049 ¦Ìg C.¦Ìg C-1.d-1, respectively, whereas after the addition of detritus, the overall rate increased to 0.536 ¦Ìg C ¦Ìg.C-1.d-1. Highly significant differences were found between grazing rates on detritus and planktonic fractions. Consumers showed higher filtration rates on microzooplankton than on phytoplankton although 78% of the cells ingested (54.7% ¦Ìg C) came from the latter. Results seem to evidence a higher contribution of detritus to the natural diet of mesozooplankton in late spring. The omnivory of A. tonsa and the high turbidity of Bah¨ªa Blanca estuary may explain the differences observed in carbon intake among food fractions.-1.d-1 and 1.501 ¦Ìg C.grazer-1.d-1. Mean weight-specific ingestion rates upon phytoplankton and microzooplankton were 0.0059 and 0.0049 ¦Ìg C.¦Ìg C-1.d-1, respectively, whereas after the addition of detritus, the overall rate increased to 0.536 ¦Ìg C ¦Ìg.C-1.d-1. Highly significant differences were found between grazing rates on detritus and planktonic fractions. Consumers showed higher filtration rates on microzooplankton than on phytoplankton although 78% of the cells ingested (54.7% ¦Ìg C) came from the latter. Results seem to evidence a higher contribution of detritus to the natural diet of mesozooplankton in late spring. The omnivory of A. tonsa and the high turbidity of Bah¨ªa Blanca estuary may explain the differences observed in carbon intake among food fractions.-1.d-1. Mean weight-specific ingestion rates upon phytoplankton and microzooplankton were 0.0059 and 0.0049 ¦Ìg C.¦Ìg C-1.d-1, respectively, whereas after the addition of detritus, the overall rate increased to 0.536 ¦Ìg C ¦Ìg.C-1.d-1. Highly significant differences were found between grazing rates on detritus and planktonic fractions. Consumers showed higher filtration rates on microzooplankton than on phytoplankton although 78% of the cells ingested (54.7% ¦Ìg C) came from the latter. Results seem to evidence a higher contribution of detritus to the natural diet of mesozooplankton in late spring. The omnivory of A. tonsa and the high turbidity of Bah¨ªa Blanca estuary may explain the differences observed in carbon intake among food fractions.-1.d-1, respectively, whereas after the addition of detritus, the overall rate increased to 0.536 ¦Ìg C ¦Ìg.C-1.d-1. Highly significant differences were found between grazing rates on detritus and planktonic fractions. Consumers showed higher filtration rates on microzooplankton than on phytoplankton although 78% of the cells ingested (54.7% ¦Ìg C) came from the latter. Results seem to evidence a higher contribution of detritus to the natural diet of mesozooplankton in late spring. The omnivory of A. tonsa and the high turbidity of Bah¨ªa Blanca estuary may explain the differences observed in carbon intake among food fractions.-1.d-1. Highly significant differences were found between grazing rates on detritus and planktonic fractions. Consumers showed higher filtration rates on microzooplankton than on phytoplankton although 78% of the cells ingested (54.7% ¦Ìg C) came from the latter. Results seem to evidence a higher contribution of detritus to the natural diet of mesozooplankton in late spring. The omnivory of A. tonsa and the high turbidity of Bah¨ªa Blanca estuary may explain the differences observed in carbon intake among food fractions.A. tonsa and the high turbidity of Bah¨ªa Blanca estuary may explain the differences observed in carbon intake among food fractions.