Rising levels of temperature and CO2 antagonistically affect phytoplankton primary productivity in the South China Sea

Highlights

• Ocean warming and acidification individually increased phytoplankton productivity of western South China Sea.
• The combination of high temperature and high CO2 showed an antagonistic effect on phytoplankton productivity.
• High temperature decreased Chl a concentrations in off-shore waters at ambient CO2.
• High CO2 level increased night respiration in the coastal waters at ambient temperatures.

Abstract

Coastal and offshore waters in the South China Sea are warming and becoming acidified due to rising atmospheric levels of carbon dioxide (CO2), yet the combined effects of these two stressors are poorly known. Here, we carried out shipboard incubations at ambient (398 μatm) and elevated (934 μatm) pCO2 at in situ and in situ+1.8 °C temperatures and we measured primary productivity at two coastal and two offshore stations. Both warming and increased CO2 levels individually increased phytoplankton productivity at all stations, but the combination of high temperature and high CO2 did not, reflecting an antagonistic effect. Warming decreased Chl a concentrations in off-shore waters at ambient CO2, but had no effect in the coastal waters. The high CO2 treatment increased night time respiration in the coastal waters at ambient temperatures. Our findings show that phytoplankton assemblage responses to rising temperature and CO2 levels differ between coastal and offshore waters. While it is difficult to predict how ongoing warming and acidification will influence primary productivity in the South China Sea, our data imply that predicted increases in temperature and pCO2 will not boost surface phytoplankton primary productivity.

Zhang Y., Wang T., Li H., Bao N., Hall-Spencer J. M. & Gao K., in press. Rising levels of temperature and CO2 antagonistically affect phytoplankton primary productivity in the South China Sea. Marine Environmental Research. Article (subscription required).

0 Responses to “Rising levels of temperature and CO2 antagonistically affect phytoplankton primary productivity in the South China Sea”



  1. Leave a Comment

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google+ photo

You are commenting using your Google+ account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

This site uses Akismet to reduce spam. Learn how your comment data is processed.




Subscribe to the RSS feed

Powered by FeedBurner

Follow AnneMarin on Twitter

Blog Stats

  • 1,128,568 hits

OA-ICC HIGHLIGHTS

Ocean acidification in the IPCC AR5 WG II

OUP book