Variability of Chlorophyll a off Southwestern Nova Scotia in Late Fall and Its Relationship to Water Column Stability

1984 ◽  
Vol 41 (12) ◽  
pp. 1730-1738 ◽  
Author(s):  
R. O. Fournier ◽  
R. Ernst ◽  
N. B. Hargreaves ◽  
M. Van Det ◽  
D. Douglas
Keyword(s):  
Nova Scotia ◽  
Chlorophyll A ◽  
Gulf Of Maine ◽  
Saline Water ◽  
Background Level ◽  
Water Column Stability ◽  
Convective Mixing ◽  
Late Fall ◽  
Chlorophyll Distribution ◽  
Salinity Water

Chlorophyll a, nitrate, and physical variables collected during December 1978 and November 1979 off southwest Nova Scotia show two distinct patterns in phytoplankton abundance. In December 1978, conditions were similar to those expected in late fall over temperate North American shelves. The water was well mixed and chlorophyll was at background level (~0.5 mg/m3). By contrast, in November 1979, both inshore and offshore regions were stratified, and chlorophyll levels were, in some places, 5 times above background. Two explanations are offered for this bimodal chlorophyll distribution. Offshore, temporary stratification resulted from the intrusion of warm saline water from either the slope or the Gulf of Maine. This may be a temporary condition that eventually deteriorates with seasonal cooling and convective mixing. Inshore, stratification results from the influx of a shallow layer of relatively low-salinity water carried by the Nova Scotia current. The onset and seasonal vagaries of this current help to explain differences observed in 1978 and 1979.

scholarly journals Water Relations and Gas Exchanges of West Indian Cherry under Salt Stress and Nitrogen and Phosphorus Doses

2017 ◽  
Vol 9 (10) ◽  
pp. 168 ◽  
Author(s):  
Francisco V. da S. Sá ◽  
Hans R. Gheyi ◽  
Geovani S. de Lima ◽  
Emanoela P. de Paiva ◽  
Pedro D. Fernandes ◽  
...  
Keyword(s):  
Chlorophyll A ◽  
Water Relations ◽  
Irrigation Water ◽  
Chlorophyll A Fluorescence ◽  
Saline Water ◽  
Block Design ◽  
West Indian ◽  
N Fertilization ◽  
Nitrogen And Phosphorus ◽  
Gas Exchanges

This study aimed to evaluate the interaction between the fertilization with nitrogen (N) and phosphorus (P) and irrigation with saline water on the water relations, gas exchanges and chlorophyll a fluorescence in West Indian cherry in the vegetative stage. The study was carried out in protected environment, using lysimeters filled with clay loam Regolithic Neosol, with low P content, installed in a randomized block design, arranged in a factorial scheme with five levels of electrical conductivity of irrigation water (ECw), and four managements of P and N fertilization, with three replicates and one plant per plot. Along the experiment, water relations, gas exchanges and chlorophyll a fluorescence were evaluated in West Indian cherry plants. The increase in irrigation water salinity reduces the gas exchanges of the plants, but the increment of 40% in N supply increases the photosynthetic activity of West Indian cherry at recommendation levels higher than 100:100% of the P/N ratio, when irrigated with ECw of up to 3.0 dS m-1. The combined action of N and P, at doses of 140:140% N/P recommendation, increases leaf turgor in the plants, regardless of the ECw level. The increment of 40% in N dose reduces the effects of salinity on the initial fluorescence of chlorophyll a in West Indian cherry irrigated with up to 2.2 dS m-1.

scholarly journals Salt tolerant acrylamide-based quenched polyampholytes for polymer flooding

2020 ◽  
Vol 100 (4) ◽  
pp. 119-127
Author(s):  
N. Mukhametgazy ◽  
◽  
I.Sh. Gussenov ◽  
A.V. Shakhvorostov ◽  
S.E. Kudaibergenov ◽  
...  
Keyword(s):  
Oil Recovery ◽  
Saline Water ◽  
Core Sample ◽  
Polymer Flooding ◽  
Trimethylammonium Chloride ◽  
Salt Tolerant ◽  
High Salinity Water ◽  
Cationic Monomer ◽  
Aqueous Salt Solutions ◽  
Salinity Water

In our previous papers [1, 2] we considered the behavior of linear and crosslinked polyampholytes based on fully charged anionic monomer — 2-acrylamido-2-methyl-1-propanesulfonic acid sodium salt (AMPS) and cationic monomer — (3-acrylamidopropyl)trimethylammonium chloride (APTAC) in aqueous-salt solutions, swelling and mechanical properties. In the present paper we report the applicability of salt tolerant amphoter-ic terpolymers composed of AMPS, APTAC and acrylamide (AAm) in enhanced oil recovery (EOR). The amphoteric terpolymers of different compositions, particularly [AAm]:[AMPS]:[APTAC] = 50:25:25; 60:20:20; 70:15:15; 80:10:10 and 90:5:5 mol.% were prepared by free-radical polymerization, identified and their viscosifying ability with respect to reservoir saline water (salinity is 163 g⋅L-1) at 60 °C was tested. It was found that due to polyampholytic nature, the AAm-AMPS-APTAC terpolymers exhibited improved viscosifying behavior at high salinity water. As a result, the appropriate salt tolerant sample [AAm]:[AMPS]:[APTAC] = 80:10:10 mol.% was selected for polymer flooding experiments. Polymer flood-ing experiments on high permeable sand pack model demonstrated that only 0.5 % oil was recovered by am-photeric terpolymer. While injection of polyampholyte solution into preliminarily water flooded core sample resulted in the increase of oil recovery up to 4.8–5 %. These results show that under certain conditions the amphoteric terpolymers have a decent oil displacement ability.

scholarly journals Growth and gas exchange of corn under salt stress and nitrogen doses

2021 ◽  
Vol 25 (3) ◽  
pp. 174-181
Author(s):  
Henderson C. Sousa ◽  
Geocleber G. de Sousa ◽  
Carla I. N. Lessa ◽  
Antonio F. da S. Lima ◽  
Rute M. R. Ribeiro ◽  
...  
Keyword(s):  
Stomatal Conductance ◽  
Gas Exchange ◽  
Leaf Area ◽  
Plant Height ◽  
Saline Water ◽  
Saline Stress ◽  
Low Salinity ◽  
Salinity Water ◽  
Hybrid Maize ◽  
The University

ABSTRACT The excess of salts can affect several processes in the crops, and nitrogen (N) can attenuate the depressive effect of salinity. The objective was to evaluate the influence of nitrogen doses on the growth and gas exchange of corn crop irrigated with saline water. The experiment was conducted from June to September 2019 at the University of International Integration of Afro-Brazilian Lusophony, Redenção, CE, Brazil. The experimental design was completely randomized, in a 2 x 3 factorial scheme (supply water of 0.3 dS m-1 and saline solution of 3.0 dS m-1) and three nitrogen doses, 0, 80, and 160 kg ha-1, corresponding to 0, 50, and 100% of the recommended dose respectively, with six repetitions. At 30 and 45 days after sowing (DAS), plant height, leaf area, number of leaves, photosynthesis, transpiration, and stomatal conductance were evaluated. Saline stress affects plant height, leaf area, photosynthesis, transpiration, and conductance at 30 DAS. The doses of 80 and 160 kg ha-1 provide greater performance in plant height, leaf area, photosynthesis, transpiration, and conductance at 30 DAS. The use of low salinity water and doses of 80 and 160 kg ha-1 were more efficient in terms of plant height, leaf area, photosynthesis, transpiration, and conductance at 45 DAS. The dose of 160 kg ha-1 of N attenuates the harmful effects of salts in AG 1051 hybrid maize plants, providing higher values of photosynthesis, transpiration, and stomatal conductance at 45 DAS when irrigated with water of 3.0 dS m-1.

scholarly journals Modeling the influence of low-salinity water inflow on winter-spring phytoplankton dynamics in the Nova Scotian Shelf–Gulf of Maine region

2008 ◽  
Vol 30 (12) ◽  
pp. 1399-1416 ◽  
Author(s):  
Rubao Ji ◽  
Cabell S. Davis ◽  
Changsheng Chen ◽  
David W. Townsend ◽  
David G. Mountain ◽  
...  
Keyword(s):  
Gulf Of Maine ◽  
Water Inflow ◽  
Phytoplankton Dynamics ◽  
Scotian Shelf ◽  
Low Salinity ◽  
Low Salinity Water ◽  
Salinity Water ◽  
Nova Scotian

The Formation of High Nutrient–Low Salinity Water in the Gulf of Maine: a Nutrient Trap?

1996 ◽  
Vol 42 (5) ◽  
pp. 617-628 ◽  
Author(s):  
C. Garside ◽  
J.C. Garside ◽  
M.D. Keller ◽  
M.E. Sieracki
Keyword(s):  
Gulf Of Maine ◽  
Low Salinity ◽  
Low Salinity Water ◽  
High Nutrient ◽  
Salinity Water

scholarly journals Radish (Raphanus sativus L.) morphophysiology under salinity stress and ascorbic acid treatments

2018 ◽  
Vol 36 (3) ◽  
pp. 257-265
Author(s):  
Ana Gabriela de Sousa Basílio ◽  
Leonardo Vieira De Sousa ◽  
Toshik Iarley Da Silva ◽  
Joana Gomes De Moura ◽  
Anderson Carlos de Melo Gonçalves ◽  
...  
Keyword(s):  
Ascorbic Acid ◽  
Chlorophyll A ◽  
Irrigation Water ◽  
Raphanus Sativus ◽  
Saline Water ◽  
Block Design ◽  
Total Content ◽  
Shoot Height ◽  
Fluorescence Maximum ◽  
Raphanus Sativus L

The use of saline or low-quality water in agriculture is an alternative to increasing water demand, especially in arid or semi-arid regions. However, the use of water with high levels of salts causes disturbances in plants, which can lead to their death; thus, alternatives to mitigate these effects are relevant in current agriculture. Currently, antioxidants are used to mitigate the effects of salts in plants, and among them ascorbic acid has been frequently mentioned. Therefore, the aim of this study was to evaluate the effect of irrigation with saline water combined with applications of ascorbic acid on the development and photosynthetic activity of radish (Raphanus sativus L.) plants. This experiment was carried out in a greenhouse with a randomized block design, with the treatments distributed in a 5.5 incomplete factorial scheme, composed of five electrical conductivities of the irrigation water (ECw): 0.50, 1.30, 3.25, 5.20 and 6.00 dS m-1, and five ascorbic acid (AA) doses: 0.00, 0.29, 1.00, 1.71, and 2.00 mM. The evaluated variables were: shoot height, leaf number, tuberous root diameter, chlorophyll a, b and total content, chlorophyll a/b ratio, initial fluorescence, maximum fluorescence, variable fluorescence and quantum yield of photosystem II. The saline water influenced the analyzed variables in the radish crop regardless of the ascorbic acid application. The ascorbic acid was not efficient in attenuating the deleterious effect of salinity in the irrigation water on the development and fluorescence of the radish. However, it was observed that the concentration of 1.00 mM of ascorbic acid promoted an increase in chlorophyll a, b and total in the saltstressed radish plants.

scholarly journals Localized Basal Freezing Within George VI Ice Shelf, Antarctica

1988 ◽  
Vol 34 (116) ◽  
pp. 71-77 ◽  
Author(s):  
M. Pedley ◽  
J.G. Paren ◽  
J.R. Potter
Keyword(s):  
Freezing Point ◽  
Saline Water ◽  
Thick Layer ◽  
Ice Shelf ◽  
Low Salinity ◽  
Ice Surface ◽  
Salinity Water ◽  
Basal Melting ◽  
Surface Ice

AbstractHobbs Pool is an area of thin ice shelf situated within George VI Ice Shelf, Antarctica. Thicker ice shelf surrounding Hobbs Pool isolates the upper 155 m of the water column from water lying at the same depth else-where under the ice shelf. Summer melt-water lakes drain through crevasses at Hobbs Pool forming a 155 m thick layer of low-salinity water close to its freezing point. Colder and more saline water in the lower part of this layer leads toin-situfreezing of fresher water lying above it. Below 155 m depth, the water temperature and salinity are linearly related by basal melting which is observed elsewhere under the ice shelf. The surface ice shows areas of deformation and deposits of subglacial rock debris which may result from upward particle paths in the area. The raising of subglacial rock debris on to the ice surface may provide a mechanism for the transport of erratics across the ice shelf to Alexander Island from the base of Palmer Land glaciers.

Warm currents affecting the spring and winter distributions of living coccolithophores in the Yellow Sea, China

2013 ◽  
Vol 42 (4) ◽  
Author(s):  
Qingshan Luan ◽  
Jianqiang Sun ◽  
Mingxiang Niu ◽  
Jun Wang
Keyword(s):  
Yellow Sea ◽  
The Yellow Sea ◽  
Yellow Sea Warm Current ◽  
Warm Current ◽  
Cell Abundance ◽  
Water Column Stability ◽  
Convective Mixing ◽  
The Southern Yellow Sea ◽  
Increasing Temperature ◽  
Living Coccolithophores

AbstractSpring and winter distributions of living coccolithophores in the Yellow Sea were studied using a polarizing microscope based on two surveys in April 2010 and January 2011. Nine species were recorded, including Emiliania huxleyi and Gephyrocapsa oceanica as the predominant forms. The cell abundance of all coccolithophores in the spring was significantly higher than in the winter (p<0.01), with means of 15 387 and 2470 cells l-1, respectively. Notably, we observed a habitat selection of coccolithophores in the southeastern Yellow Sea (32–35°N, 123–125°E). This habitat was characterized by sharp temperature gradients during both seasons caused by water exchange between the shelf waters and the Yellow Sea Warm Current. Moreover, the cell abundance, standing crop and estimated fluxes of coccolithophores were abnormally high compared to other regions. The habitat preference of coccolithophores in the Yellow Sea was directly related to the hydrodynamic conditions. The unfavorable light conditions caused by the intense convective mixing were responsible for the low biomass of coccolithophores during the winter. However, the increasing temperature influenced by the warm current, in combination with water column stability, triggered the spring bloom of coccolithophores in the southern Yellow Sea.

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