Rising CO2 and increased light exposure synergistically reduce marine primary productivity, supplement to: Gao, Kunshan; Xu, Juntian; Gao, Guang; Li, Yahe; Hutchins, David A; Huang, Bangqin; Wang, Lei; Zheng, Ying; Jin, Peng; Cai, Xiaoni; Häder, Donat-Peter; Li, Wei; Xu, Kai; Liu, Nana; Riebesell, Ulf (2012): Rising CO2 and increased light exposure synergistically reduce marine primary productivity. Nature Climate Change, 2, 519–523

• Main Authors: Gao, Kunshan, Xu, Juntian, Gao, Guang, Li, Yahe, Hutchins, David A, Huang, Bangqin, Wang, Lei, Zheng, Ying, Jin, Peng, Cai, Xiaoni, Häder, Donat-Peter, Li, Wei, Xu, Kai, Liu, Nana, Riebesell, Ulf
• Format: Dataset
• Language: English
• Published: PANGAEA - Data Publisher for Earth & Environmental Science 2012
• Subjects: Bottles or small containers/Aquaria <20 L; Chromista; Coast and continental shelf; Entire community; Growth/Morphology; Laboratory experiment; Light; North Pacific; Ochrophyta; Pelagos; Phaeodactylum tricornutum; Phytoplankton; Primary production/Photosynthesis; Single species; Skeletonema costatum; Temperate; Thalassiosira pseudonana; Tropical; Event label; Figure; Treatment; DATE/TIME; Time of day; Irradiance; Non photochemical quenching, standard deviation; Duration; Season; Species; Irradiance, standard deviation; Growth rate; Growth rate, standard deviation; Yield ratio; Non photochemical quenching; Primary production of carbon, per volume of seawater; Primary production of carbon, standard deviation; Primary production of carbon, per chlorophyll a; Temperature, water; pH; Phosphate; Chlorophyll a; Primary production of carbon; Salinity; pH, standard deviation; Alkalinity, total; Alkalinity, total, standard deviation; Carbon, inorganic, dissolved; Carbon, inorganic, dissolved, standard deviation; Partial pressure of carbon dioxide water at sea surface temperature wet air; Bicarbonate ion; Bicarbonate ion, standard deviation; Carbonate ion; Carbonate ion, standard deviation; Carbonate system computation flag; Carbon dioxide; Fugacity of carbon dioxide water at sea surface temperature wet air; Aragonite saturation state; Calcite saturation state; In situ sampler; Potentiometric; Calculated using CO2SYS; Calculated using seacarb after Nisumaa et al. 2010; Ocean Acidification International Coordination Centre OA-ICC; Pacific; Ocean acidification
• Online Access: https://dx.doi.org/10.1594/pangaea.821019; https://doi.pangaea.de/10.1594/PANGAEA.821019

Carbon dioxide and light are two major prerequisites of photosynthesis. Rising CO2 levels in oceanic surface waters in combination with ample light supply are therefore often considered stimulatory to marine primary production. Here we show that the combination of an increase in both CO2 and light exposure negatively impacts photosynthesis and growth of marine primary producers. When exposed to CO2 concentrations projected for the end of this century, natural phytoplankton assemblages of the South China Sea responded with decreased primary production and increased light stress at light intensities representative of the upper surface layer. The phytoplankton community shifted away from diatoms, the dominant phytoplankton group during our field campaigns. To examine the underlying mechanisms of the observed responses, we grew diatoms at different CO2 concentrations and under varying levels (5-100%) of solar radiation experienced by the phytoplankton at different depths of the euphotic zone. Above 22-36% of incident surface irradiance, growth rates in the high-CO2-grown cells were inversely related to light levels and exhibited reduced thresholds at which light becomes inhibitory. Future shoaling of upper-mixed-layer depths will expose phytoplankton to increased mean light intensities. In combination with rising CO2 levels, this may cause a widespread decline in marine primary production and a community shift away from diatoms, the main algal group that supports higher trophic levels and carbon export in the ocean. : In order to allow full comparability with other ocean acidification data sets, the R package seacarb (Lavigne and Gattuso, 2011) was used to compute a complete and consistent set of carbonate system variables, as described by Nisumaa et al. (2010). In this dataset the original values were archived in addition with the recalculated parameters (see related PI). The date of carbonate chemistry calculation by seacarb is 2013-10-31.