| Автор | Drits, Alexander V. |
| Автор | Arashkevich, Elena G. |
| Автор | Semenova, Tatjana N. |
| Дата выпуска | 1992 |
| dc.description | Pyrosomas are the large group of pelagic tunicates whose trophic role in pelagic communities has not yet been sufficiently studied. We ran across a local area of high concentration of the most widespread and commonest species of pyrosomas, Pyrosoma atlanticum, 450 miles off the Congo river mouth. The following was estimated: gut pigment content, defecation rate, organic carbon and pigment content of fecal pellets, and sinking rate. Based on these data and the measured number of pyrosomas colonies the grazing impact on phytoplankton and the fecal pellet flux were calculated. During the night swarms of 50–65 mm P.atlanticum removed 53% of phytoplankton standing stock in the 0–10 m layer; sparsely distributed pyrosomas consumed only 4%. The grazing impact in the 0–50 m layer was only 12.5 and <1% respectively. The fecal pellet flux resulting from nocturnal feeding of P.atlanticum while swarming made up 1.4–1.6 × 10<sup>6</sup> pellets m<sup>−2</sup> 10 h<sup>−1</sup> or 305–1035 mg C m<sup>−2</sup> 10 h<sup>−1</sup> and 1.4 × 10<sup>5</sup> pellets m<sup>−2</sup> 10 h<sup>−1</sup> or 87.4 mg C m<sup>−2</sup> 10 h<sup>−1</sup> while non-swarming. Incubation experiments showed the rapid degradation of fecal pellets at 23°C: the loss of pigment and carbon content was ˜60–70% after 45 h. We believe that given the sinking rate of 70 m day<sup>−1</sup> the main part of fecal material does not leave the upper water column and is retained in the trophic web of the epipelagic layer. |
| Формат | application.pdf |
| Издатель | Oxford University Press |
| Копирайт | © Oxford University Press |
| Тема | ORIGINAL ARTICLES |
| Название | Pyrosoma atlanticum (Tunicata, Thaliacea): grazing impact on phytoplankton standing stock and role in organic carbon flux |
| Тип | research-article |
| Electronic ISSN | 1464-3774 |
| Print ISSN | 0142-7873 |
| Журнал | Journal of Plankton Research |
| Том | 14 |
| Первая страница | 799 |
| Последняя страница | 809 |
| Аффилиация | Institute of Oceanology Academy of Science USSR117218, Krasikova, 23, Moscow, USSR |
| Выпуск | 6 |
