Synergistic effects of pCO2 and iron availability on nutrient consumption ratio of the Bering Sea phytoplankton community

Little is known concerning the effect of CO2 on phytoplankton ecophysiological processes under nutrient and trace element-limited conditions, because most of the CO2 manipulation experiments have been conducted under these element-replete conditions. To investigate the effects of CO2 and iron availability on phytoplankton ecophysiology, we conducted an experiment using a phytoplankton community in the iron-limited, high-nutrient, low-chlorophyll (HNLC) region of the Bering Sea basin in September 2009. Carbonate chemistry was controlled by the bubbling of the several levels of CO2 concentration (180, 380, 600, and 1000 ppm) controlled air, and two iron conditions were established with or without the addition of inorganic iron. We demonstrated that in the iron-limited control conditions, the specific growth rate and the maximum photochemical quantum efficiency (Fv/Fm) of photosystem (PS) II decreased with increasing CO2 levels, suggesting a~further decrease in iron bioavailability under the high CO2 conditions. In addition, biogenic silica to particulate nitrogen and biogenic silica to particulate organic carbon ratios increased from 2.65 to 3.75 and 0.39 to 0.50, respectively with an increase in CO2 level in the iron-limited controls. In contrast, in the iron-added treatments, specific growth rate, Fv/Fm values and elemental compositions did not change in response to the CO2 variations, indicating that the addition of iron cancelled out the effect of the modulation of iron bioavailability due to the change in carbonate chemistry. Our results suggest that high CO2 conditions can alter the biogeochemical cycling of nutrients through decreasing iron bioavailability in the iron-limited HNLC regions in the future.

Sugie K., Endo H., Suzuki K., Nishioka J., Kiyosawa H. & Yoshimura T., 2013. Synergistic effects of pCO2 and iron availability on nutrient consumption ratio of the Bering Sea phytoplankton community. Biogeosciences Discussions 10: 4331-4365. Article.

0 Responses to “Synergistic effects of pCO2 and iron availability on nutrient consumption ratio of the Bering Sea phytoplankton community”



  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 )

Twitter picture

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

Facebook photo

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

Google+ photo

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

Connecting to %s




Subscribe to the RSS feed

Powered by FeedBurner

Follow AnneMarin on Twitter

Blog Stats

  • 760,126 hits

Ocean acidification in the IPCC AR5 WG II

OUP book


Follow

Get every new post delivered to your Inbox.

Join 936 other followers