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.