Phenological Changes of Blooming Diatoms Promoted by Compound Bottom-Up and Top-Down Controls
详细信息 查看全文
- 作者：Valeria A. Guinder ; Juan Carlos Molinero ; Celeste M. López Abbate…
- 关键词：Plankton ; Grazing selectivity ; Phenology ; Structural equation modeling ; Estuaries
- 刊名：Estuaries and Coasts
- 出版年：2017
- 出版时间：January 2017
- 年：2017
- 卷：40
- 期：1
- 页码：95-104
- 全文大小：
- 刊物类别：Earth and Environmental Science
- 刊物主题：Environment, general; Ecology; Freshwater & Marine Ecology; Environmental Management; Coastal Sciences; Water and Health;
- 出版者：Springer US
- ISSN：1559-2731
- 卷排序：40
文摘
Understanding phytoplankton species-specific responses to multiple biotic and abiotic stressors is fundamental to assess phenological and structural shifts at the community level. Here, we present the case of Thalassiosira curviseriata, a winter-blooming diatom in the Bahía Blanca Estuary, Argentina, which displayed a noticeable decrease in the past decade along with conspicuous changes in phenology. We compiled interannual field data to assess compound effects of environmental variations and grazing by the invasive copepod Eurytemora americana. The two species displayed opposite trends over the period examined. The diatom decreased toward the last years, mainly during the winters, and remained relatively constant over the other seasons, while the copepod increased toward the last years, with an occurrence restricted to winter and early spring. A quantitative assessment by structural equation modeling unveiled that the observed long-term trend of T. curviseriata resulted from the synergistic effects of environmental changes driven by water temperature, salinity, and grazing. These results suggest that the shift in the abundance distribution of T. curviseriata toward higher annual ranges of temperature and salinity—as displayed by habitat association curves—constitutes a functional response to avoid seasonal overlapping with its predator in late winters. The observed changes in the timing and abundance of the blooming species resulted in conspicuous shifts in primary production pulses. Our results provide insights on mechanistic processes shaping the phenology and structure of phytoplankton blooms.