期刊
DEEP-SEA RESEARCH PART II-TOPICAL STUDIES IN OCEANOGRAPHY
卷 169, 期 -, 页码 -出版社
PERGAMON-ELSEVIER SCIENCE LTD
DOI: 10.1016/j.dsr2.2019.104638
关键词
ENSO; Blob; Krill; Forage food; Upwelling; Baja California
类别
资金
- Consejo Nacioanl de Ciencia y Tecnologia (CONACYT) [G0041T, G35326T, 42569, 23947]
- Secretatia de Medio Ambiente y Recursos Naturales (SEMARNAT-CONACYT) [23804]
- University of California Institute for Mexico and the United States [UCMEXUS CN07-125]
Euphausiids represent a significant part of the total zooplankton biomass and are a key link in the trophic web of the California Current System (CCS). During 2014-2016, the northeast Pacific experienced warming caused by two successive events, the Blob and the 2015-2016 El Nino, which affected the whole ecosystem. Here we present evidence for a strong impact of the 2014-2016 warm events on euphausiids in the Baja California region, namely two species (Euphausia pacifica and Nematoscelis difficilis) that are dominant in the CCS transition zone. Both species decreased approximately 95% in relation to the previous years (1999-2010). A similar decrease was observed for E. pacifica during the 1997-1998 El Nino, but the decrease in N. difficilis was higher in 2014-2016 and unprecedented during the 1997-2016 period. Biomass of the coastal species Nyctiphanes simplex showed negative anomalies during the Blob but not during the 2015-2016 El Nino. The tropical species Euphausia eximia and Euphausia recurva increased in biomass during the Blob in 2014 relative to the previous years, and even more during the 2015-2016 El Nino. The strong increase of E. eximia, E. recurva, and N. simplex during El Nino may have been due to upwelling activity in winter 2015-2016. Canonical correspondence analysis (CCA) was performed to assess the relation between the euphausiid community and environmental variables. The most influential variables were temperature and chlorophyll, and to a lesser extent salinity. The subarctic E. pacifica showed covariance with chlorophyll while a set of tropical species did with thermohaline conditions. However, the variance accounted for was low (20% taking the first three axis). N. difficilis did not show significant scores in the CCA suggesting that other variables such as availability of prey could be important for this carnivore species.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据