Biological Impacts on marine organisms in high CO2 world Yoshihisa Shirayama Seto Marine Biological Laboratory Kyoto University

contents Direct chronic impacts of raised concentration of atmospheric CO2 on shallow water organisms –Adults –Early development Acute impacts of largely raised concentration of sea- water CO2 on deep-sea organisms due to ocean sequestration –Lethal –Sublethal –Benthic chamber

Estimated pH change of the seawater in AD Before the industrial revolution Present 2100 CO2 IPCC IS92a H PCO 2 (ppm) B1 Scenario A1F1 Scenario

Meaning of Ocean Sequestration CO2 concentration Year A: no sequestration; B: 50% at 1500m; C: 50% at 4000%; D: 100% at 1500m; E: 100% at 4000m

Approach Shallow water – +200 ppm to +2,000 ppm air bubbling – long-term culturing (up to 6 months) –Calcareous shelled animals Sea urchin snail

Shallow water calcareous species used in the long-term experiment Hemicentrotus pulcherrimus Echinometra mathaei Strombus luhuanus

Survival: Experiment 1 Control 560ppm

Growth: Hemicentrotus pulcherrimus Experiment 1 Experiment 3 Control 109% CO 2 65% Control 155% CO 2 100%

Growth : Echinometra mathaei Experiment 1 Experiment 3 Control 51% CO 2 36% Control 26% CO 2 -7%

Growth: Strombus luhuanus (Expt 1) Length Weight Control 22% CO 2 17% Control 74% CO 2 56%

Damage of shell at ppm

Approach to Deep-sea Sequestration modification Laboratory experiment – +2,000 ppm to +20,000 ppm air bubbling – lethal impacts – Sublethal impacts in situ experiment – benthic chamber – ppm, ppm

+5000 ppm is not acutely lethal on adult copepods

Impacts on reproduction of copepods

control ppm pH A B Fertilized eggs, %

Fig 4 4 cell/fert 2 cell/fert 1 cell/fert A control (8.0)(7.8)(7.6) (7.4)(7.0)(6.8) ppm (pH) B Cleavaged embryos,%

Impact of high CO2 in the early life stage of sea urchins

A B CD E F G HIJK L Morphology of sea urchin larvae in high CO2 sea water

Benthic Chamber

Experiments so far conducted CruiseDepth (m)Exposure time (h) Exposure pCO2 (ppm) K , (control) 5,000 (LCO2) 20,000 (HCO2) KT K

Abundance of meiobenthos No. of individuals in 0-3 cm layer

Abundance of Bacteria Mean of 0-3cm surface

Future research needs Shallow water –Impacts on reproduction –More precise simulation (daily fluctuation etc.) –Ecosystem approach –Modeling Deep-sea sequestration –Precise simulation of CO2 change –More information on sublethal impacts –In situ approach especially ecosystem level –Modeling Public outreach