Potential environmental changes in the western Arctic and the western North Pacific: their impacts on lower trophic level organisms

Transcription

1 North Pacific Marine Science Organization 2016 Annual Meeting -25 years of PICES: Celebrating the past, Imagining the Future- Potential environmental changes in the western Arctic and the western North Pacific: their impacts on lower trophic level organisms Naomi Harada, Katsunori Kimoto, Masahide Wakita, Tetsuichi Fujiki, Keisuke Shimizu, Jonaotaro Onodera Japan Agency for Marine Science and Technology

2 Today s topics Monitoring sites, sub-arctic North Pacific and western Arctic Ocean New technique to quantify the response of marine calcifier to ocean acidification Time series data of shell density, pteropods from Arctic Ocean and planktic foraminifera from North Pacific Comparison of genetic diversity of pteropods between Atlantic and Pacific Outlook for future

3 Aragonite saturation in 2100 (Ω aragonite) Sub-Arctic and Polar Seas: Low CO3 2- brings low Ω Ω = [Ca 2+ ] [CO3 2- ] / K sp Saturation index (Ω) K sp : solubility product of calcite/aragonite Ω>1: precipitation(shell preserved) Ω<1: undersaturation (shell dissolved)

4 Sentinel observation: sub-arctic North Pacific WMO GREENHOUSE GAS BULLETIN The State of Greenhouse Gases in the Atmosphere Based on Global Observations through 2013 St. K2: 47N, 160E Surface ph reduction: /yr Deployment of sediment trap: 2008 ~ (ongoing) Two traps: 1000m, 4000m ISSN No November 2014 CO 2 mole fraction, ppm ph ph Trend expected from fossil-fuel burning Land and ocean sinks MUNIDA 8.05 KNOT/K DYFAMED 7.95 ph CARIACO Station P HOT BATS ESTOC 137 E section Measurements 1990 of atmospheric carbon 2005 dioxide (CO ) and oxygen (O 2 ) concentrations continue to provide Year strong insights into human-induced deviations in the global carbon cycle. The rise in atmospheric CO 2 has been well documented since 1958, when high-precision Land sink MUNIDA KNOT/K DYFAMED Institution of Oceanography, is shown in the righthand figure. Oxygen abundance is reported as Year relative changes in the oxygen/nitrogen (O 2 /N 2 ) ratio. A decrease of 100 per meg [1] corresponds to the loss of Figure 6. Time series of de-seasonalized surface seawater 100 ph O 2 and molecules respective for trendlines every million (left) O and 2 molecules of de-seasonalized in the surface pco measurements began at Mauna Loa, under the direction atmosphere. Atmospheric O 2 has decreased very slightly, of C.D. Keeling, 2 (µatm) and respective trendlines (right). Featured time series include the Bermuda Atlantic Time-series Study (BATS; blue) the as European shown in Station the left-hand for Time figure. Series The in the as Ocean it is consumed near the Canary during Islands combustion (ESTOC; of purple), fossil fuels. the Hawaii The Ocean practices Time-series applied (HOT; at grey); that time CARIACO to ensure (red); high-quality Station P (black); observed MUNIDA decrease (green); in the O 2 Kyodo is less North than Pacific predicted Time by series the (KNOT; measurements orange); the station were known adopted as the for Dynamics observations of Atmospheric by amount Fluxes of in fossil the MEDiterranean fuels combusted, Sea (DYFAMED; because, as yellow); plants the Japan Global Meteorological Atmosphere Agency Watch 137 E participants. section The repeat rise hydrographic of CO 2 take line up at CO 10 N, 2 through 137 E photosynthesis, (137 E section; pink). O 2 is returned The locations to of the concentration featured time has series been are only shown about in Figure half of 2. what Temporal would sampling the atmosphere. resolution varies The O 2 from offset monthly therefore to annually. quantifies the be expected if all the excess CO 2 from the burning of magnitude of the land CO 2 sink. The ocean CO 2 sink fossil fuels stayed in the air. The other half has been can then also be calculated based on the requirement absorbed by the land biosphere and the oceans, but that the combined sinks sum to the total established Table 2. Linear trends and standard errors for surface ph a and pco the split between land and oceans is not easily resolved from the CO 2 at the nine featured ocean time series 2 data. The O 2 data also resolve fluctuations from Time COseries 2 data alone. This is where ph O 2 (yr measurements ) pco seasonally and on other timescales, which provide 2 (µatm yr 1 ) Reference prove useful. additional information about the large-scale functioning BATS b ± ±0.08 of the Earth s biosphere that Bates complements et al., 2014 CO 2 data. One of the longest O 2 time series, from flasks collected (Figures courtesy of R. Keeling, Scripps Institution of Bates et al., 2014 at Cape ESTOC Grim, Tasmania and analysed ± at the Scripps 1.78±0.15 Oceanography, USA) González-Dávila et al., 2010 HOT b ± ±0.15 Executive summary with CO 2 at 396.0±0.1 ppm [2], CH Bates 4 et 1824±2 al., 2014 ppb [3] and N 2 O CARIACO b ± ±0.37 at 325.9±0.1 ppb. These values Astor constitute, et al., 2013respectively, The latest analysis of observations from the WMO Global 142%, 253% and 121% of pre-industrial (before 1750) levels. Atmosphere DYFAMED Watch b (GAW) Programme ± shows that the globally 2.56±0.85 The atmospheric increase Touratier of CO and 2 from Goyet, to 2013 was averaged mole fractions of carbon dioxide (CO 2 ), methane 2.9 ppm, which is the largest year Bates to et year al., 2014 change from 1984 (CH 4 ) and MUNIDA nitrous b oxide (N 2 O) reached ± new highs in 2013, 1.55±0.24 to For N 2 O the increase from 2012 to 2013 is smaller Currie et al., 2011 O 2 abundance, per meg ESTOC BATS 137 E section CARIACO HOT Station P Trend expected from fossil-fuel burning Bates et al., 2014 Dore et al., 2009 KNOT/K2 b ± ±0.67 Wakita et al., 2013 Station P c c c Wong et al., ºE section at 10ºN d ± ±0.06 Midorikawa et al., 2010 pco 2 (µatm) pco 2 (µatm) pco 2 (µatm) a b ph in total hydrogen ion concentration scale at in situ temperatures. Data of ph and pco were calculated from measurements of total dissolved inorganic carbon, total alkalinity, temperature and salinity

5 Ω in the mixed layer at K2 Aragonite saturation horizon: 120m Calcite saturation horizon: 150m Less than 1 after ~2100? Wakita et al., in prep Largest annual reduction rate at K2

6 Sentinel observation:arctic Oceans St. NAP: 75N, 162W Deployment: 2010 ~ ongoing 2 Sed.Traps: 200m, 1300m By Arctic Monitoring & Assessment Programme Area ph Ω Nordic Seas Surface Bottom Bering Sea Surface Bottom Siberian Shelves Surface Bottom Chukchi & Beaufort shelves Surface Bottom Canadian Archipelago Surface Bottom Central Arctic Surface Bottom ~

7 Decreasing Ωar by sea ice melt (Sep. 2012) 1<Ωar Sea ice melt Ωar (5m) Salinity (5m) Trap site Undersaturated subsurface water for aragonite dissolved living pteropod shells?

8 Influence of acidification to marine ecosystem

9 Time-series mooring system with multi sensors Measurement buoy Measurement buoy ARGO Mini-FRRF セジメントトラップ Sediment trap Sensors CTD DO sensor Illuminance sensor Fast repetition rate fluorometry (FRRF) Acoustic doppler current profiler (ADCP) Remote access sampler (RAS) ph/pco 2 sensor Automatic lifting winch Mooring system with automatic lifting device Sediment trap

10 Motivation of development of new technique Ø Reducing of carbonate ions by ocean acidification will accelerate shell dissolution or to prevent the production of carbonate shelled organisms. Ø Marine plankton is the largest carbonate producer in the world. Especially, the global planktic foraminiferal flux to the ocean floor of GTC y 1 accounts for 32 80% of the total deep marine calcite budget (Schiebel, 2002). Ø Serious damage of marine plankton due to OA potentially give a negative impact on food web. Ø There is no well quantitative and comparable estimation method to evaluate impacts (damages) of the ocean acidification on marine plankton. So, we have developed new technique to quantify carbonate density. Coccolithophore 5 µm Planktic foraminifera 100 µm Pteropods 1 mm

11 Micro focus X-ray Computing Tomography method Micro X-CT (MXCT) Scan Fluoroscopic image Reconstruct a a. Specimen b c b. Standard material (Calcite) c. Position maker

12 Calcite CT Number as a shell density index relative value of X-ray attenuation coefficient in each voxels Calcite CT Number = µsample - µair µcalcite - µair x 1000 µsample: X-ray attenuation coefficient of samples µair: X-ray attenuation coefficient of the surrounding air = µcalcite: X-ray attenuation coefficient of calcite (standard material:calcite or Aragonite ) = 1000 Mean CT number vs Shell density Air (0) 600 (lower density) (reference) (higher density)

13 MXCT: 3 Dimension precise morphometry Thecosomata (Pteropod): Limacina helicina (spatial resolution:0.8 µm) High density 1200 The biggest advantages of MXCT are: Cross section image of carbonate shell Quantitative 600 Low density Nondestructive

14 Summary Micro-Focus X-ray Computing Tomography (MXCT) technique can be applied successfully to evaluate the impact of OA for marine calcifiers quantitatively. Carbonate density of marine calcifier changes seasonally and 35-40% reduction were observed in specific seasons in sub-arctic NP (winter) and Arctic Ocean (summer & beginning of sea-ice season). Further sentinel time series observation (e.g. mooring and float) is important to understand responses of marine organisms on rapid acidifying in sub-arctic and Arctic Ocean. MXCT has a potential to be common standard method to evaluate the shelled plankton responses on OA.-----more higher trophic level plankton (e.g., Copepoda---chitinous substance)

15 Outlook for future Application of carbonate density as an Essential Ocean Valuables of marine calcifier for ocean acidification To make carbonate density popular as EOV for OA, JAMSTEC can provide the technique how to analyze carbonate density by MXCT and is also preparing to receive measurement request from the world. Further connecting/networking time-series sites with basin (e.g., GACS) and global scales (e.g., Argo) observing programs to understand complicated responses of marine organisms to OA with other environmental stressors.

16 Please contact us if you are interested in MXCT (N. Harada) (K. Kimoto)