Marine Ecosystems Research Department - jamstec japan agency ...

More documents

Recommendations

Info

JAMSTEC 2002 Annual Report Marine Ecosystems Research Department veyed the state of the current to determine the process of seawater exchange in Sekisei Lagoon. From this, we estimated that the exchange of seawater takes about ten days. Our survey on the current carried out during the coral spawning period suggests that it takes several days for coral eggs and larvae to flow out to the open ocean from within the lagoon depending on the spawning area. At the same time, we were able to ascertain the synoptic circulation pattern of Sekisei Lagoon. These results were presented in Japanese scientific journals, and at international conferences and symposiums. Search for micro-pore filters available for use under high temperature and high pressure conditions Period: FY-FY "Chemical Evolution" is the process of chemical changes from inorganic to organic substrates prior to the origin of life. Various experiments have been done to show certain aspects of this process; the first of which is called Miller's experiments done by Miller in . In this experiment, water (H O), methane (CH ), ammonia (NH ) and hydrogen (H ) were used as the gaseous components that were believed to be present on the early earth. These chemicals were all sealed inside a sterile array of glass tubes and flasks, and were heated (in place of volcanic activities) and subjected to electrical discharges (in place of lightning). This experiment showed that organic compounds such as amino acids, which are essential to cellular life, could be made easily under the conditions that were believed to be present on the early earth. However, recent studies showed that the atmosphere of the early earth was an oxidizing environment unlike Miller's experiment conditions and that in such oxidizing conditions, it is quite difficult to synthesize any organic substrates. Since the discovery of deep-sea hydrothermal vents in the Galapagos Rift in , many scientists have been considering that such an environment could be a possible candidate for Chemical Evolution. The reasons are as follows: () High temperature energy for chemical reactions () Reducing environment required condition for inanimate syntheses of organic substrates () High concentration of heavy metals catalysts for chemical reactions A large number of in vitro experiments have been conducted to investigate this possibility. Several types of amino acids were synthesized under artificial hydrothermal vent conditions. Spherical structures composed of membranes also appeared under such conditions. However, these experiments were performed using limited trace elements under limited fluctuation conditions within a limited time frame. In situ experiments on Chemical Evolution at deepsea hydrothermal vents are expected to show novel reaction processes and products but there has been no previous attempt because of the difficulty of access to deep-sea vents and in developing an in situ experimental device. Here we began to search for micro-pore filters that are the most important components of the in situ device. The filters must have tolerance to high temperature and high pressure, be permeable to small molecules like the inorganic substrates derived from vent fluid, and prevent synthesized large organic molecules from flowing out of the reaction chambers. In fiscal we carried out in situ experiments on micro-pore filters at hydrothermal vents on Hatoma Knoll in the Okinawa Trough. We positioned the test devices at the hydrothermal vent with a maximum temperature of ˚C. We recovered the devices about a week later and found a large amount of hydrothermal deposits we assume to be sulfide attached to the inside of the filter chambers (Fig.). We also found that the titanium parts making up the devices had not corroded at all. The silicon nitride filters in the in situ testing units showed no noticeable deformation, and had uniformly turned black. Internally, the eight filter units were deformed in that they all showed signs of partial fusion (Fig.). 56
Japan Marine Science and Technology Center Marine Ecosystems Research Department On board we tested each of the recovered units for concentrations of silicic acid and ammonia, and detected high concentrations of these chemicals from the units comprising silicon nitride filters. We believe this was from the reduction of the silicon nitride filters caused by reducing substances (e.g., hydrogen sulfide, methane, and hydrogen) in the hydrothermal fluid. Fig.13 Hydrothermal deposits attached to the filter test unit Fig.14 Silicon nitride filter showing internal deformation Study on the uptake of various elements using Porites corals Period: FY-FY Stable carbon and oxygen isotope measurement on biogenic carbonate provides various information for reconstructing past oceanic environments. For example, O/ O ratios correlate to the calcification temperature in the seawater. In contrast, C/ C is considered as a proxy for dissolved organic carbon in seawater, symbiont photosynthesis and seawater [CO ] - . In this study, C/ C and O/ O on coral skeletons (Genus Porites) have been measured with different growth rates. As a result, fast-growing corals showed the correlation with photosynthetic activity, while slowgrowing corals showed the opposite correlation. It implies that the correlation between C/ C and O/ O depends on the relative intensities of the kinetic isotope effect with calcification and metabolic isotope a Distance from surface (mm) b Distance from surface (mm) 20 15 10 5 0 20 15 10 5 0 δ 18 O, δ 13 C (‰) -6 -4 -2 δ 18 O δ 13 C δ 18 O, δ 13 C (‰) 97 98 99 00 -6 -6 97 98 99 00 -4 -2 -4 -2 δ 18 O δ 13 C -6 -4 -2 St.8-1 (Porites lobata) St.19-5 (Porites lobata) Fig.15 X-ray photographs showing annual growth bands and δ 13 C (open circles) and δ 18 O (filled circles) values of Porites specimens versus the distance from surface of coral colonies along the growth axis. δ 18 O cycles correspond to seasonal changes of seawater temperature and the year is labeled at the growing part. The phase offsets between δ 13 C and δ 18 O change with growth rate. 57
Page 2 and 3:
JAMSTEC 2002 Annual Report J apan M
Page 4 and 5: Japan Marine Science and Technology
Page 26 and 27: JAMSTEC 2002 Annual Report Marine T
Page 48 and 49: JAMSTEC 2002 Annual Report Marine E
Page 104 and 105:
Japan Marine Science and Technology
Page 106 and 107:
Page 108 and 109:
Page 110 and 111:
Page 112 and 113:
JAMSTEC 2002 Annual Report Frontier
Page 114 and 115:
Page 116 and 117:
Page 118 and 119:
Page 120 and 121:
Page 122 and 123:
Page 124 and 125:
Page 126 and 127:
Page 128 and 129:
Page 130 and 131:
Page 132 and 133:
Page 134 and 135:
Page 136 and 137:
Page 138 and 139:
Page 140 and 141:
Page 142 and 143:
Page 144 and 145:
Page 146 and 147:
Page 148 and 149:
Page 150 and 151:
Page 152 and 153:
Page 154 and 155:
Page 156 and 157:
Page 158 and 159:
1000 Japan Marine Science and Techn
Page 160 and 161:
Page 162 and 163:
Page 164 and 165:
Page 166 and 167:
Page 168 and 169:
Page 170 and 171:
Page 172 and 173:
Page 174 and 175:
Page 176 and 177:
Page 178 and 179:
JAMSTEC 2002 Annual Report Mutsu Re
Page 180 and 181:
JAMSTEC 2002 Annual Report Mutsu Re
Page 182 and 183:
Page 184 and 185:
Page 186 and 187:
Page 188 and 189:
Page 190 and 191:
Page 192 and 193:
Page 194 and 195:
JAMSTEC 2002 Annual Report Research
Page 196 and 197:
Page 198 and 199:
Page 200 and 201:
Page 202 and 203:
Page 204 and 205:
Page 206 and 207:
Page 208 and 209:
Page 210 and 211:
Page 212 and 213:
Page 214 and 215:
Page 216 and 217:
Page 218 and 219:
Page 220 and 221:
Page 222 and 223:
Page 224 and 225:
Page 226 and 227:
Page 228 and 229:
Page 230 and 231:
Page 232 and 233:
Page 234 and 235:
Page 236 and 237:
Page 238 and 239:
Page 240 and 241:
Page 242 and 243:
Page 244 and 245:
Page 246 and 247:
Page 248 and 249:
Page 250 and 251:
Page 252 and 253:
Page 254 and 255:
Page 256 and 257:
Page 258 and 259:
Page 260 and 261:
Page 262 and 263:
Page 264 and 265:
Page 266 and 267:
Page 268 and 269:
Page 270 and 271:
Page 272 and 273:
Page 274 and 275:
Page 276 and 277:
JAMSTEC 2002 Annual Report PATENT .
Page 278:
JAMSTEC Japan Marine Science and Te
show all

Marine Ecosystems Research Department - jamstec japan agency ...

Create successful ePaper yourself

Delete template?

Save as template?