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 On the Albedo of Snow in Antarctica: A Contribution to I.A.G.O.

1988 ◽  
Vol 34 (116) ◽  
pp. 19-25 ◽  
Author(s):  
Gerd Wendler ◽  
John Kelley
Keyword(s):  
Simple Model ◽  
Diurnal Variation ◽  
Austral Summer ◽  
Cloud Amount ◽  
Mechanical Action ◽  
List Type ◽  
Solar Elevation ◽  
Solar Noon ◽  
Terre Adélie ◽  
Very High

AbstractAs part of a larger experiment, detailed albedo measurements were carried out during the austral summer of 1985-86 in the dry-snow zone (1560 m) of Terre Adélie, eastern Antarctica. The following results were found:(1)Mean albedo values were high (around 82.6%). On clear days, the albedo showed some dependency on the solar elevation. The dependency was slight for solar elevations above 12° but became larger with low Sun angles.(2)The albedo was found to be a function of cloud amount and type, increasing with the amount and thickness of clouds. In white-out conditions, very high albedos were found (>90%).(3)The albedo showed a dependency on the type of snow. New snow displayed higher values than older snow, whose crystals had been destroyed by mechanical action.(4)A simple model was developed to assess the influence of sastrugi on the albedo. This model could explain the asymmetric diurnal variation about solar noon of the measured albedo above a sastrugi field.The above four dependencies might explain the considerable discrepancies which can be found in the literature concerning the snow albedo of Antarctica.

scholarly journals Impact of vertical and horizontal advection on nutrient distribution in the southeast Pacific

Ocean Science ◽  
2016 ◽  
Vol 12 (4) ◽  
pp. 1003-1011 ◽  
Author(s):  
Bàrbara Barceló-Llull ◽  
Evan Mason ◽  
Arthur Capet ◽  
Ananda Pascual
Keyword(s):  
Vertical Velocity ◽  
Nitrate Uptake ◽  
Austral Summer ◽  
Lagrangian Particle ◽  
Nutrient Distribution ◽  
Uptake Rates ◽  
Southeast Pacific ◽  
Omega Equation ◽  
The Impact ◽  
Initial Distributions

Abstract. An innovative approach is used to analyze the impact of vertical velocities associated with quasi-geostrophic (QG) dynamics on the redistribution and uptake of nitrate in the southeast Pacific (SEP). A total of 12 years of vertical and horizontal currents are derived from an observation-based estimate of the ocean state. Horizontal velocities are obtained through the application of thermal wind balance to weekly temperature and salinity fields. Vertical velocities are estimated by integration of the QG omega equation. Seasonal variability of the synthetic vertical velocity and kinetic energy associated with the horizontal currents is coincident, with peaks in austral summer (November–December) in accord with published observations. The impact of vertical velocity on SEP nitrate uptake rates is assessed by using two Lagrangian particle tracking experiments that differ according to vertical forcing (ω = ωQG vs. ω = 0). From identical initial distributions of nitrate-tagged particles, the Lagrangian results show that vertical motions induce local increases in nitrate uptake reaching up to 30 %. Such increases occur in low uptake regions with high mesoscale activity. Despite being weaker than horizontal currents by a factor of up to 10−4, vertical velocity associated with mesoscale activity is demonstrated to make an important contribution to nitrate uptake, hence productivity, in low uptake regions.

Effect of UVB Irradiation on Cu2+-Binding Organic Ligands and Cu2+ Speciation in Alpine Lake Waters of New Zealand

2005 ◽  
Vol 2 (1) ◽  
pp. 56 ◽  
Author(s):  
Sylvia Sander ◽  
Jonathan P. Kim ◽  
Barry Anderson ◽  
Keith A. Hunter
Keyword(s):  
New Zealand ◽  
Surface Waters ◽  
Natural Waters ◽  
Austral Summer ◽  
Organic Ligands ◽  
Conditional Stability ◽  
Uvb Radiation ◽  
Dissolved Metals ◽  
Conditional Stability Constant ◽  
Uvb Irradiation

Environmental Context. The bioavailability of dissolved metals in natural waters is directly affected by metal-sequestering agents. These agents include soil-derived matter and compounds released by microorganisms, since copper can support or inhibit aquatic microorganisms depending on concentration. During summer the levels of copper increase in surface waters, an effect intuitively attributable to increased ultraviolet light degrading the sequestering agents more effectively, leading to a concurrent release of the metal. This paper shows that the amount of degradation attributable to light is too low to explain the metal release and that a biological influence may instead be responsible. Abstract. The influence of UVB irradiation on the Cu2+ binding by natural organic ligands in six alpine lakes on the South Island, New Zealand, has been investigated using competitive ligand equilibration with salicylaldoxime and detection by cathodic stripping voltammetry (CLE-CSV). During austral summer 2002–2003 the total dissolved Cu ([Cu]T), the concentration of strong Cu2+-binding ligands ([L]T), and their conditional stability constant K´´ were determined in surface samples of all six lakes. All lakes exhibited appreciable concentrations of a strong Cu2+ binding ligand with similar K´´ values and concentrations always exceeding [CuT], thus dominating Cu2+ speciation. Four lakes (Hayes, Manapouri, Wanaka, Te Anau) showed no appreciable trend in [LT] throughout the summer, whereas in Lakes Wakatipu and Hawea [LT] increased steadily throughout this period. Laboratory UVB irradiation of lake water samples using a 400 W mercury lamp with a Pyrex glass filter (λ > 280 nm) showed that Cu2+-binding ligands are destroyed by UVB radiation, causing [L]T to decrease with a rate of –0.588 nmol L–1 h–1 (r2 0.88). From this we calculate that the in situ ligand destruction rate by UVB in summer for surface waters of these lakes is too small to significantly affect [LT], and conclude that variations in ligand concentrations must result from seasonally variable biological factors.

scholarly journals TO THE QUESTION OF COMPREHENSIVE ASSESSMENT OF SURFACE WATER IN THE CENTRAL CAUCASUS DURING WINTER BETWEEN AND SUMMER FLOOD

2021 ◽  
Vol 6 (5(55)) ◽  
pp. 22-27
Author(s):  
Liliya Zuberovna Zhinzhakova ◽  
Elena Alexandrovna Cherednik
Keyword(s):  
Water Quality ◽  
Surface Waters ◽  
Inorganic Nitrogen ◽  
High Water ◽  
Polluted Water ◽  
Trace Impurities ◽  
Central Caucasus ◽  
Summer Flood

Based on long-term observations, the assessment of the pollution of the rivers of the Central Caucasus was carried out by comparing the calculated coefficients of the complexity of pollution and the specific combinatorial index of pollution of surface waters, and the quality classes were determined. The results of chemical analysis of the concentration levels of trace impurities (Mo, Pb, Zn, V, Ni, Cr, Mn, Ag) and inorganic nitrogen compounds (NO2 -, NO3 — and NH4 +) in the waters of 13 rivers in two permanent sections of each watercourse were used. The results of calculating the indicators of pollution in the waters of rivers of winter low water and summer high water are presented. The most polluted watercourses and the frequency of pollution in each river are identified, estimated by the values of the specific combinatorial index of water pollution, the coefficient of complexity of pollution, and the class of water quality is presented. The assessment of the most polluted water bodies during the winter low-water period and summer flood is given according to the classification of water quality. According to long-term observations, the features of watercourses and their differences in terms of pollution are presented.

scholarly journals Karakteristik Hydrocyclone untuk Pemisahan Minyak dan Air

2020 ◽  
Vol 4 (2) ◽  
pp. 133
Author(s):  
Dian Ratna Suminar ◽  
Nurcahyo Nurcahyo
Keyword(s):  
High Water ◽  
Petroleum Exploration ◽  
Pipe Diameter ◽  
High Water Content ◽  
Optimum Flow Rate ◽  
Cylindrical Section ◽  
Overflow Pipe ◽  
Design And Manufacture ◽  
Very High ◽  
Optimum Flow

Eksplorasi minyak bumi dari sumur-sumur yang sudah tua menghasilkan minyak dengan kandungan air tinggi. Hydrocyclone suatu alat yang berfungsi untuk pemisahan cair-cair berdasarkan perbedaan berat jenis setiap komponen. Pemisahan ini terjadi dikarenanakan adanya gaya sentrifugal dan gaya gravitasi yang dihasilkan dari bentuk hydrocyclone yang seperti kerucut. Perancangan dan pembuatan hydrocyclone menghasilkan alat dengan spesifikasi sebagai berikut : diameter pipa masukan : 25,4 mm, diameter cylindrical section : 120 mm, tinggi cylindrical section : 120 mm, tinggi cone section : 600 mm, diameter pipa overflow : 25,4 mm, diameter pipa underflow : 25,4 mm. Laju alir optimum untuk pemisahan air-minyak tanah pada hydrocyclone adalah 91,8 liter/menit dengan kadar minyak tanah di overflow sebesar 11,4% dan kadar minyak tanah di underflow sebesar 3%.Petroleum exploration from old wells produces oil with a very high water content. Hydrocyclone is a device that functions for liquid-liquid separation based on differences in specific gravity of each component. This separation occurs due to the presence of centrifugal forces and gravitational forces resulting from cone-like forms of hydrocyclone. The design and manufacture of hydrocyclone produces tools with the following specifications: input pipe diameter: 25.4 mm, cylindrical section diameter: 120 mm, high cylindrical section: 120 mm, cone section height: 600 mm, overflow pipe diameter: 25.4 mm, underflow pipe diameter: 25.4 mm. The optimum flow rate for the separation of water-kerosene on hydrocyclone is 91.8 liters / minute with the level of kerosene in overflow of 11.4% and the level of kerosene in underflow of 3%.

Sign in / Sign up

Export Citation Format

Share Document