A Coastal Jet in the Chukchi Sea

Data collected in the nearshore region between Point Lay and Ice Cape, Alaska, support the thesis that a well-developed coastal jet is present during the summer. The temporal variability of the current is as predicted by theory. The physical characteristics of the region suggest a strong signal-to-noise ratio for the baroclinic coastal jet. It is probably the dominant mode of summer coastal circulation for the entire Chukchi Sea coast of the Alaskan North Slope

A three-dimensional current meter for estuarine applications

A curr ent meter that is capable of measuring the high-frequency fluctuations of the three-dimensional velocity vector has been developed. The meter works on a doppler-shift principle. At high velocities, the meter has been shown to have an accuracy of better than 3%

A Preliminary Mass Balance Model of Primary Productivity and Dissolved Oxygen in the Mississippi River Plume/Inner Gulf Shelf Region

A deterministic, mass balance model for phytoplankton, nutrients, and dissolved oxygen was applied to the Mississippi River Plume/Inner Gulf Shelf (MRP/IGS) region. The model was calibrated to a comprehensive set of field data collected during July 1990 at over 200 sampling stations in the northern Gulf of Mexico. The spatial domain of the model is represented by a three-dimensional, 21-segment water-column .grid extending from the Mississippi River Delta west to the Louisiana-Texas border, and from the shoreline seaward to the 30-60 m bathymetric contours. Diagnostic analyses and numerical experiments were conducted with the calibrated model to better understand the environmental processes controlling primary productivity and dissolved oxygen dynamics in the MRP/IGS region. Underwater light attenuation appears relatively more important than nutrient limitation in controlling rates of primary productivity. Chemical-biological processes appear relatively more important than advective-dispersive transport processes in controlling bottom-water dissolved oxygen dynamics. Oxidation of carbonaceous material in the water column, phytoplankton respiration, and sediment oxygen demand all appear to contribute significantly to total oxygen depletion rates in bottom waters. The estimated contribution of sediment oxygen demand to total oxygen-depletion rates in bottom waters ranges from 22% to 30%. Primary productivity appears to he an important source of dissolved oxygen to bottom waters in the region of the Atchafalaya River discharge and further west along the Louisiana Inner Shelf. Dissolved oxygen concentrations appear very sensitive to changes in underwater light attenuation due to strong coupling between dissolved oxygen and primary productivity in bottom waters. The Louisiana Inner Shelf in the area of the Atchafalaya River discharge and further west to the Texas border appears to be characterized by significantly different light attent, ation-depth-primary productivity relationships than the area immediately west of the Mississippi Delta. Nutrient remineralization in the water column appears to contribute significantly to maintaining chlorophyll concentrations on the Louisiana Inner Shelf

Hydrographic, biological, and nutrient characteristics of the water column on the Louisiana shelf, July, 1987

Beginning in 1985, several research cruises were conducted by our research team to assess the spatial and temporal extent, intensity, and potential causes of oxygen depletion in the northern Gulf of Mexico. Hypoxic bottom waters were studied along two transects in and near the Mississippi River Delta Bight in 1985 and 1986. In addition, shelf-wide cruises were conducted from the Mississippi River to the Texas border during July of both years. The intent of these cruises was to provide comparative information on the temporal variability of oxygen-depleted bottom waters on the Louisiana shelf. The bi-weekly cruises along the southeastern Louisiana shelf were discontinued in 1987. A shelf-wide cruise, however, was conducted in July, 1987 to continue the studies of temporal variability on the Louisiana shelf. The cruise was conducted on the R/V Pelican from July 1 through July 5

08/10/1948 Letter from the Health and Welfare Department of Lewiston, Maine

Letter from Robert J. Wiseman, Jr., M. D., Health Officer with the Lewiston Health and Welfare Department, to Mrs. Carmen Vachon.https://digitalcommons.usm.maine.edu/fac-lpg-letters-1948-07-12/1013/thumbnail.jp

Hydrographic, biological, and nutrient characteristics of the water column on the Louisiana shelf, July and September, 1985

In June 1985, a focused study was initiated to assess the spatial and temporal extent, intensity, and potential causes of oxygen depletion in the northern Gulf of Mexico. Two shelf-wide, quasi-synoptic cruises were conducted from the Mississippi River to the Texas border during mid-July and early September, 1985. Cruises were conducted aboard the R/V Pelican on 15-20 July and 10-13 September. Stations were occupied along ten transects in 5 to 80 m water depth. Stations for Pelican Cruise I extended farther offshore and farther to the west than those for Pelican Cruise II. In addition to these shelf-wide cruises, hypoxic bottom waters were studied more frequently along two transects in the Mississippi River Delta Bight area

Hydrographic, biological, and nutrient characteristics of the water column on the Louisiana shelf during 1988

Since 1985, several research cruises were conducted by our research team to assess the spatial and temporal extent, intensity, and potential causes of oxygen depletion in the northern Gulf of Mexico. Hypoxic bottom waters were studied along two transects in and near the Mississippi River Delta Bight in 1985 and 1986. In addition, shelf-wide cruises were conducted from the Mississippi River to the Texas border during July of 1985, 1986, and 1987. These cruises have provided us with exhaustive information concerning the temporal and spatial variability associated with the phenomenon of hypoxia on the Louisiana shelf. It was not our intent to continue assessment-type cruises during 1988. Opportunities existed, however, in conjunction with other research cruises and the LUMCON summer program to re-occupy stations along Transect C off Cat Island Pass near Cocodrie. In addition, the drought conditions in the upper Mississippi River basin during the spring and summer of 1988 resulted in a significant reduction in the flow rate of the Mississippi River. We were therefore compelled to conduct a shelf-wide cruise during mid-summer of 1988 to document the hydrographic conditions of the Louisiana shelf under low flow conditions of the Mississippi River and to assess the effects of this low flow on the phenomenon of hypoxia. The cruises along Transect C were conducted on board the R/V Pelican as part of a research effort named LaSER for data in April and as part of the LUMCON summer program for the remainder. The shelf-wide cruise was conducted on board the R/V Acadiana from August 12 through August 16, 1988

Hydrographic, biological, and nutrient characteristics of the water column in the Mississippi River Delta Bight, June, 1985 to December, 1985

In June 1985, a focused study was initiated to assess the spatial and temporal extent, intensity, and potential causes of oxygen depletion in the northern Gulf of Mexico. Hypoxic bottom waters were studied along two transects (one off Cat Island Pass near Cocodrie and one off Belle Pass off Port Fourchon) in the Mississippi River Delta Bight area. Eight 2-day cruises were conducted aboard the R/V R.J. Russell or the R/V Pelican along these two transects between mid-June and mid-October. Sampling was most intense (bi-weekly) from mid-June through early September. A reduced sampling scheme (4 stations along the Cat Island Pass transect) was continued through the end of the year. In addition, two shelf-wide cruises were conducted from the Mississippi River to the Texas border during July and September