Sensors and Systems for in situ Observations of Marine Carbon Dioxide System Variables

Autonomous chemical sensors are required to document the marine carbon dioxide system's evolving response to anthropogenic CO2 inputs, as well as impacts on short- and long-term carbon cycling. Observations will be required over a wide range of spatial and temporal scales, and measurements will likely need to be maintained for decades. Measurable CO2 system variables currently include total dissolved inorganic carbon (DIC), total alkalinity (AT), CO2 fugacity (fCO2), and pH, with comprehensive characterization requiring measurement of at least two variables. These four parameters are amenable to in situ analysis, but sustained deployment remains a challenge. Available methods encompass a broad range of analytical techniques, including potentiometry, spectrophotometry, conductimetry, and mass spectrometry. Instrument capabilities (precision, accuracy, endurance, reliability, etc.) are diverse and will evolve substantially over the time that the marine CO2 system undergoes dramatic changes. Different suites of measurements/parameters will be appropriate for different sampling platforms and measurement objectives

Coastal sedimentation: Point San Pedro to Miramontes Point, California

The distribution and dispersal patterns of sand-size particles has been investigated along a portion of the California coast south of San Francisco. The effectiveness of long-term, net littoral transport in the area has been evaluated through hydrodynamic considerations and through considerations of the dispersal patterns of sand. The distribution and dispersal patterns presented are based upon results of a vector analysis of the raw heavy mineral da ta, Four sedimentary provinces have been delineated. One blankets the continental shelf in the area studied and represents premodern sediment deposited during the last major regression and transgression of the sea. The remaining three represent Holocene deposits on the pre-modern sediment. The latter are only of local extent and are contiguous with their sources. These mineralogical changes along the coast preclude the existence of net littoral transport under present conditions. This conclusion agrees well with that predicted by hydrodynamic considerations. The contrasting picture presented by the widespread, relatively homogeneous pre-modern province and the localized, varied Holocene deposits is pximarily due to changes in littoral transport attendant with the rise in sea level to its present position

A reconnaissance heavy mineral study of Monteray Bay beach sediment

The shoreline of Monterey Bay is beached over most of its length. The beach is essentially continuous except for the northern and southern ends of the bay which are characterized by numerous pocket beaches separated by narrow cliffed areas which extend to beyond the low water level. There appears to be no large supply of sand to the beaches at present as the rivers entering the bay are, with few exceptions, flooded estuaries that are ponded up to 20 miles upstream from the shore of the bay. It is probable that this 30 mile stretch of shoreline has reached a state of equilibrium under present hydrodynamic conditions. The present study is of a preliminary nature and was undertaken to determine if a static equilibrium does exist, if there is any significant transport along the shores of the bay, and to delineate what are the littoral transport patterns, if any. The approach used has been that of a heavy mineral study of the sand sized particles in the beach samples collected. Samples were grouped on the basis of their contained heavy mineral suites and in this manner large sedimentary provinces were delineated on the basis of similarity of heavy mineral composition. The relationships between the various provinces and between the provinces and physiographic features has been used to determine the littoral transport patterns and their relation to present conditions