MEPS 132:257-263 (1996)  -  doi:10.3354/meps132257

The effect of environmental variables on 13C discrimination by two marine phytoplankton

Johnston AM

The effects that environmental variables, other than dissolved CO2, have on 13C discrimination by marine phytoplankton were studied. Two selected species showed different responses. The delta13C values of the marine diatiom Phaeodactylum tricornutum grown in a range of temperatures with a constant dissolved [CO2] were more negative as the growth temperature decreased. delta13C values of P. tricornutum showed little response to changes in growth photon flux density (except at low PFD <10 umol m-2 s-1) and growth pH. delta13C values of the prymnesiophyte Emiliania huxleyi were more negative with decreased growth temperature, more negative with decreased growth PFD and less negative with decreased growth pH. The distinct effects which environmental variables have on the delta13C values of 2 contrasting algal species suggest that species-specific responses to environmental change may be important in understanding the variability of delta13C values found in particulate organic carbon obtained from oceanic and coastal waters. The role of environmental variables in hindcasting dissolved [CO2] is discussed.

13C discrimination . Emiliania huxleyi . Phaeodactylum tricornutum . Temperature . pH . Photon flux density

Full text in pdf format