Shell condition and survival of Puget Sound pteropods are impaired by ocean acidification conditions

We tested whether the thecosome pteropod Limacina helicina from Puget Sound, an urbanized estuary in the northwest continental US, experiences shell dissolution and altered mortality rates when exposed to the high CO2, low aragonite saturation state (Omega a) conditions that occur in Puget Sound and the northeast Pacific Ocean. Five, week-long experiments were conducted in which we incubated pteropods collected from Puget Sound in four carbon chemistry conditions: current summer surface (460-500 µatm CO2, Omega a=1.59), current deep water or surface conditions during upwelling (760 and 1600-1700 µatm CO2, Omega a=1.17 and 0.56), and future deep water or surface conditions during upwelling (2800-3400 µatm CO2, Omega a=0.28). We measured shell condition using a scoring regime of five shell characteristics that capture different aspects of shell dissolution. We characterized carbon chemistry conditions in statistical analyses with Omega a, and conducted analyses considering Omega a both as a continuous dataset and as discrete treatments. Shell dissolution increased linearly as aragonite saturation state decreased. Discrete treatment comparisons indicate that shell dissolution was greater in undersaturated treatments compared to oversaturated treatments. Survival increased linearly with aragonite saturation state, though discrete treatment comparisons indicated that survival was similar in all but the lowest saturation state treatment. These results indicate that, under starvation conditions, pteropod survival may not be greatly affected by current and expected near-future aragonite saturation state in the NE Pacific, but shell dissolution may. Given that subsurface waters in Puget Sound's main basin are undersaturated with respect to aragonite in the winter and can be undersaturated in the summer, the condition and persistence of the species in this estuary warrants further study.

(Table, Appendix C) Metal content of nodules at Sea Scope stations based upon XRF analyses at the Ore Microscopy Laboratory, Washington State Unicersity, USA

New information on possible resource value of sea floor manganese nodule deposits in the eastern north Pacific has been obtained by a study of records and collections of the 1972 Sea Scope Expedition. Nodule abundance (percent of sea floor covered) varies greatly, according to photographs from eight stations and data from other sources. All estimates considered reliable are plotted on a map of the region. Similar maps show the average content of Ni, Cu, Mn and Co at 89 stations from which three or more nodules were analyzed. Variations in nodule metal content at each station are shown graphically in an appendix, where data on nodule sizes are also given. Results of new analyses of 420 nodules from 93 stations for mn, fe, ni, cu, CO, and zn are listed in another appendix. Relatively high Ni + Cu content is restricted chiefly to four groups of stations in the equatorial region, where group averages are 1.86, 1.99, 2.47, and 2.55 weight-percent. Prepared for United States Department of the Interior, Bureau of Mines. Grant no. GO284008-02-MAS. - NTIS PB82-142571.

Benthic oxygen flixes on the Washington shelf and slope

Benthic oxygen fluxes calculated from in situ microelectrode profiles arc compared with benthic flux chamber O2 uptake measurements on a transect of eight stations across the continental shelf and three stations on the slope of Washington State. Station depths ranged from 40 to 630 m and bottom-water oxygen concentrations were 127-38 µM. The fluxes measured by the two methods were similar on the slope, but on the shelf, the chamber flux exceeded the microelectrode flux by as much as a factor of 3-4. We attribute this difference to pore-water irrigation, a process which apparently accounts for the oxidation of a significant amount of organic C in the continental shelf sediments. Combining our diffusive flux data with other data demonstrates clearly that the bottomwater oxygen concentration must play some significant role in determining the sedimentary oxygen consumption rate. Numerical simulation of the microelectrode 0, profiles suggests that roughly half the diffusive 0, flux must be consumed within - 1 mm of the sediment surface. If this conclusion is correct, then the magnitude of the diffusive flux depends both on the bottom-water oxygen concentration and on the supply rate of labile C to the sediment surf'ace.

Geochemistry, isotopic ratios and mineral composition of samples from ODP Leg 163 sites

Thirty-five samples from the drill core of the three Leg 163 sites (Sites 988, 989, and 990) off the southeast coast of Greenland were analyzed for 27 major, minor, and trace elements by X-ray fluorescence (XRF) and for 25 trace elements, including 14 rare-earth elements (REEs), by an inductively coupled plasma source mass spectrometer (ICP/MS). Sr- and Nd-isotope data are reported for seven samples and oxygen-isotope data are reported for 19 plagioclase separates. In addition, a reconnaissance survey of the composition of the main mineral phases, plagioclase, pyroxene, and oxides was determined on an electron microprobe to provide the basic information required for petrogenetic modeling. Olivine pseudomorphs are present in many of the samples, but in no case was an olivine grain found that was fresh enough to give a reliable analysis. The chemical and isotopic data recorded here were determined to provide a comparison with the larger data sets acquired by the Edinburgh, Copenhagen, and Leicester laboratories from both Legs 152 and 163 drill cores. This will permit a detailed comparison of the North Atlantic flood basalt province as a whole with the better known Columbia River, Deccan, and Karoo continental flood basalt provinces, for which substantial chemical data sets are already available at Washington State University.