Diatoms Dominate and Alter Marine Food-Webs When CO2 Rises

<jats:p>Diatoms are so important in ocean food-webs that any human induced changes in their abundance could have major effects on the ecology of our seas. The large chain-forming diatom Biddulphia biddulphiana greatly increases in abundance as pCO2 increases along natural seawater CO2 gradient...

Full description

Bibliographic Details
Published in:Diversity
Main Authors: Harvey, BP, Agostini, S, Kon, K, Wada, S, Hall-Spencer, JM
Format: Article in Journal/Newspaper
Language:English
Published: MDPI AG 2019
Subjects:
Online Access:http://hdl.handle.net/10026.1/16436
https://doi.org/10.3390/d11120242
Description
Summary:<jats:p>Diatoms are so important in ocean food-webs that any human induced changes in their abundance could have major effects on the ecology of our seas. The large chain-forming diatom Biddulphia biddulphiana greatly increases in abundance as pCO2 increases along natural seawater CO2 gradients in the north Pacific Ocean. In areas with reference levels of pCO2, it was hard to find, but as seawater carbon dioxide levels rose, it replaced seaweeds and became the main habitat-forming species on the seabed. This diatom algal turf supported a marine invertebrate community that was much less diverse and completely differed from the benthic communities found at present-day levels of pCO2. Seawater CO2 enrichment stimulated the growth and photosynthetic efficiency of benthic diatoms, but reduced the abundance of calcified grazers such as gastropods and sea urchins. These observations suggest that ocean acidification will shift photic zone community composition so that coastal food-web structure and ecosystem function are homogenised, simplified, and more strongly affected by seasonal algal blooms.</jats:p>