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Subtle biological responses to increased CO 2 concentrations by Phaeocystis globosa Scherffel, a harmful algal bloom species
Author(s) -
Wang Yan,
Smith Walker O.,
Wang Xiaodong,
Li Shaoshan
Publication year - 2010
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2010gl042666
Subject(s) - phytoplankton , eutrophication , algal bloom , algae , bloom , plankton , biology , ecology , trophic level , ecosystem , population , emiliania huxleyi , dinoflagellate , photosynthesis , marine ecosystem , environmental chemistry , nutrient , botany , chemistry , demography , sociology
Recent investigations into the role of carbon dioxide on phytoplankton growth and composition have clearly shown differential effects among species and assemblages, suggesting that increases in oceanic CO 2 may play a critical role in structuring lower trophic levels of marine systems in the future. Furthermore, alarming increases in the occurrence of harmful algal blooms (HABs) in coastal waters have been observed, and while not uniform among systems, appear in some manner to be linked to human impacts (eutrophication) on coastal systems. Models of HABs are in their infancy and do not at present include sophisticated biological effects or their environmental controls. Here we show that subtle biological responses occur in the HAB species Phaeocystis globosa Scherffel as a result of CO 2 enrichment induced by gentle bubbling. The alga, which has a polymorphic life history involving the formation of both colonies and solitary cells, exhibited altered growth rates of colonial and solitary forms at [CO 2 ] of 750 ppm, as well as increased colony formation. In addition, substantial modifications of elemental and photosynthetic constituents of the cells (C cell −1 , N cell −1 , potential quantum yield, chl a cell −1 ) occurred under elevated CO 2 concentrations compared to those found at present CO 2 levels. In contrast, other individual and population variables (e.g., colony diameter, total chlorophyll concentration, carbon/nitrogen ratio) were unaffected by increased CO 2 . Our results suggest that predictions of the future impacts of Phaeocystis blooms on coastal ecosystems and local biogeochemistry need to carefully examine the subtle biological responses of this alga in addition to community and ecosystem effects.