Size Distributions of Suspended Material in the Surface Waters of an Estuary as Measured by Laser Fraunhofer Diffraction

1984 ◽  
pp. 75-85 ◽  
Author(s):  
A. J. Bale ◽  
A. W. Morris ◽  
R. J. M. Howland
Keyword(s):  
Surface Waters ◽  
Size Distributions ◽  
Suspended Material ◽  
Fraunhofer Diffraction

Chemical recovery and browning of Nova Scotia surface waters in response to declining acid deposition

2021 ◽  
Author(s):  
D. Redden ◽  
B. F. Trueman ◽  
D. W. Dunnington ◽  
L. E. Anderson ◽  
G. A. Gagnon
Keyword(s):  
Nova Scotia ◽  
Acid Deposition ◽  
Surface Waters ◽  
Chemical Recovery ◽  
Size Distributions ◽  
Iron Aluminum

Colour, pH, iron, and aluminum are increasing in NS surface waters; iron/aluminum size distributions include at least two colloidal fractions.

scholarly journals ENVIRONMENTAL CONDITIONS OF THE WATERS OF THE MANZANARES RIVER, CUMANA-SUCRE, VENEZUELA

2016 ◽  
Author(s):  
Arístide Márquez ◽  
William James Senior ◽  
Gregorio Martínez ◽  
J. Castañeda
Keyword(s):  
Heavy Metals ◽  
Dissolved Oxygen ◽  
Surface Waters ◽  
Environmental Conditions ◽  
Dilution Effect ◽  
Volume Flow ◽  
Human Consumption ◽  
Suspended Material ◽  
Low Salinity ◽  
Total Ammonium

The Manzanares River is one of the more important rivers of Venezuela inasmuch as it is used to supply drinkingwater to a large part of the northeastern zone of Venezuela. For this reason a study was undertaken of the surface waters of theestuarine zone of the river, following the saline gradient from zero to salinities greater than 30. The following properties weremeasured: river volume flow, rainfall, pH, temperature, suspended materials, dissolved oxygen and ammonium, and heavy metals(Fe, Mn, Cu, Zn, Ni, Cr, Pb and Cd) in particulate and dissolved phases. River volume flow varied with seasonal rainfall throughoutthe year, as expected, while temperature varied between 24.5 and30.4 oC and pH ranged from 6.65 and 8.9. From the dry to the wetseason, suspended material increased from 23 to 880 mg/l at low salinity, and always decreased progressively as salinity increased.Concentrations of total ammonium, 14.5 to 14.3 mmol/l, were high, while those of dissolved oxygen, 3.57 to 5.27 ml/l, were low, andthese levels were even more accentuated at salinities under 5 during the dry season. The highest concentrations found for heavymetals were: Fe 406.02; Mn 5.57; Zn 2.18; Cu 0.72; Cr 0.19; Ni 0.72; Pb 0.12; Cd 0.03 mmol/l. These surpass Venezuelan legal limitsfor water intended for human consumption as well as for waters to be discharged in coastal areas. Concentrations decreased atincreased salinity because of the dilution effect, flocculation and/or precipitation in the form of oxyhydroxides. The results obtainedin this study reveal a serious deterioration of the state of the waters of the lower Manzanares river.

Particle Size Distributions from Fraunhofer Diffraction

1988 ◽  
pp. 99-105 ◽  
Author(s):  
M. Bertero ◽  
P. Boccacci ◽  
C. De Mol ◽  
E. R. Pike
Keyword(s):  
Particle Size ◽  
Size Distributions ◽  
Fraunhofer Diffraction ◽  
Particle Size Distributions

scholarly journals Impact of Freshwater Discharge on the Carbon Uptake Rate of Phytoplankton During Summer (January–February 2019) in Marian Cove, King George Island, Antarctica

2021 ◽  
Vol 8 ◽  
Author(s):  
Bo Kyung Kim ◽  
Misa Jeon ◽  
Hyoung Min Joo ◽  
Tae-Wan Kim ◽  
Sang-Jong Park ◽  
...  
Keyword(s):  
Surface Waters ◽  
Light Availability ◽  
Austral Summer ◽  
High Water ◽  
Carbon Uptake ◽  
Suspended Material ◽  
High Productivity ◽  
Uptake Rates ◽  
Control Light ◽  
Very High

Rapidly changing conditions in high-latitude coastal systems can significantly impact biogeochemical cycles because these systems are strongly influenced by freshwater discharged from melting glaciers and streams on land. Generally, Antarctic coastal areas are considered high-productivity areas in which phytoplankton growth prevails under various environmental conditions (e.g., oceanographic and meteorological conditions). This study provides carbon uptake rates of phytoplankton in Marian Cove during summer (January-February 2019). Daily depth-integrated carbon uptake varied greatly and averaged 0.8 g C m–2 day–1, with a maximum of 4.52 mg g C m–2 day–1 recorded on 14 January. Similarly, the observed biomass standing stocks were very high (up to 19.5 mg m–3 chlorophyll a) and were dominated by microphytoplankton (20–200 μm), representing 84% of total chlorophyll a (chl-a). The depth-integrated chl-a and carbon uptake decreased from outer to inner areas (close to the glacial front) in the cove. As the austral summer progressed, the freshening of the surface waters coincided with high water stability and suspended material and with low productivity when nanophytoplankton were present (2–20 μm; >60%). These findings suggest that both photosynthetically active radiation penetrating the water column and enhanced turbidity control light availability for phytoplankton, as well as their community compositions.

scholarly journals Terrigenous sedimentation on the submarine Shirshov Ridge (Bering Sea) during the last deglaciation

2019 ◽  
pp. 102-118
Author(s):  
I. O. Murdmaa ◽  
E. V. Dorokhova ◽  
E. A. Ovsepyan ◽  
O. M. Dara ◽  
D. Nürnberg
Keyword(s):  
Grain Size ◽  
Sea Ice ◽  
Bering Sea ◽  
Younger Dryas ◽  
Size Distributions ◽  
Suspended Material ◽  
Terrigenous Sedimentation ◽  
Shirshov Ridge ◽  
Grain Size Distributions ◽  
Bottom Waters

The submarine Shirshov Ridge is an independent system of terrigenous sedimentation, which is geomorphologically isolated from bottom terrigenous influx into the deep-water basin of the Bering Sea. Using the ridge as example, we studied background hemipelagic sedimentation of the finely dispersed terrigenous suspended material from water column and deposition of the coarser grained ice-rafted material in the western part of the deep-water basin. The grain-size and mineral composition of postglacial sediments of the Shirshov Ridge was studied in cores SO201-2-85KL and SO201-2-77KL taken from local basins in the central and southern parts of the ridge, respectively. Statistic treatment of uninterrupted grain-size distributions (GD) of terrigenous component of the postglacial sediments by end-member (EM) modelling revealed that the grain-size distributions of terrigenous sediments from two cores are determined by the mixing of three EMs. EM-1 and EM-2 reflect the hemipelagic sedimentation with and without bottom currents influence respectively, while EM-3 with mode at fine-grained sand characterizes GD of the ice-rafted material. Reconstructed mechanisms of terrigenous influx on the Shirshov Ridge involve advection of the suspended matter with surface and intermediate water masses and ice-rafting. The relative role of both mechanisms of the terrigenous sedimentation under the influence of varying bottom current velocities for intervals of Last Glacial Maximum, early deglaciation, Heinrich event 1, Bølling–Allerød, Younger Dryas, and Early Holocene is estimated. It is ascertained that the grain-size distribution of terrigenous component is defined by climate variations, sea ice coverage, sea ice drift pathways, conditions of fast ice melting, and mobility of bottom waters. High concentrations of drifting ice or seasonal sea ice cover likely existed above the southern part of the ridge during the second half of the Heinrich 1 event. The low mobility of bottom waters facilitated only the subice hemipelagic sedimentation of fine fractions from the background reserve of suspended material. A sharp reduction of ice-rafted flux was reconstructed for the Bølling–Allerød warming interval. Bottom currents affected sedimentation in the central part of the ridge during the entire deglaciation (in addition to the second half of the Heinrich 1 event), and in the southern part during the Bølling–Allerød, Younger Dryas, and Early Holocene.

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