scholarly journals Paratethys pacing of the Messinian Salinity Crisis: low salinity waters contributing to gypsum precipitation?

2020 ◽  
Author(s):  
Wout Krijgsman ◽  
Arjen Grothe ◽  
Federico Andreetto ◽  
Gert-Jan Reichart ◽  
Mariette Wolthers ◽  
...  
Keyword(s):  
Surface Water ◽  
Saline Water ◽  
Water Layer ◽  
Alternative Mechanism ◽  
Messinian Salinity Crisis ◽  
Apparent Paradox ◽  
Low Salinity ◽  
Gypsum Precipitation ◽  
Gypsum Formation ◽  
The Mediterranean

<p><strong>During the so-called Messinian Salinity Crisis (MSC: 5.97-5.33 Myr ago), reduced exchange with the Atlantic Ocean caused the Mediterranean to develop into a “saline giant” wherein ~</strong><strong>1 million km<sup>3</sup> of evaporites </strong><strong>(gypsum and halite) were deposited. Despite decades of research it is still poorly understood exactly how and where in the water column these evaporites formed. Gypsum formation commonly requires enhanced dry conditions (evaporation exceeding precipitation), but recent studies also suggested major freshwater inputs into the Mediterranean during MSC-gypsum formation. Here we use strontium isotope ratios of ostracods to show that low-saline water from the Paratethys Seas actually contributed to the precipitation of Mediterranean evaporites. This apparent paradox urges for an alternative mechanism underlying gypsum precipitation. We propose that Paratethys inflow would enhance stratification in the Mediterranean and result in a low-salinity surface-water layer with high Ca/Cl and SO<sub>4</sub>/Cl ratios. We show that evaporation of this surface water can become saturated in gypsum at a salinity of ~40, in line with salinities reported from fluid inclusions in MSC evaporites.</strong></p>

scholarly journals Paratethys pacing of the Messinian Salinity Crisis: Low salinity waters contributing to gypsum precipitation?

2020 ◽  
Vol 532 ◽  
pp. 116029 ◽  
Author(s):  
Arjen Grothe ◽  
Federico Andreetto ◽  
Gert-Jan Reichart ◽  
Mariette Wolthers ◽  
Christiaan G.C. Van Baak ◽  
...  
Keyword(s):  
Messinian Salinity Crisis ◽  
Low Salinity ◽  
Gypsum Precipitation

Juvenile Salmon in the Estuary and Lower Nabisipi River and Some Results of Tagging

1966 ◽  
Vol 23 (7) ◽  
pp. 947-961 ◽  
Author(s):  
Geoffrey Power ◽  
Gilles Shooner
Keyword(s):  
Growth Rate ◽  
Surface Water ◽  
Tidal Cycle ◽  
Saline Water ◽  
Juvenile Salmon ◽  
Resident Population ◽  
Low Salinity ◽  
Retarded Growth ◽  
Hydrographic Conditions ◽  
Warm Surface Water

Morphometric and hydrographic conditions indicated Nabisipi River, Quebec, has a fjord-type estuary with warm surface water of low salinity flowing out over cold saline water from the Gulf of St. Lawrence at all phases of the tidal cycle. The age, weight, and condition factors of 231 juvenile salmon from the estuary and 200 from the lower reaches of the river are given. Ages ranged from 1+ to 4+, condition factors (100 × weight in grams divided by the length in centimeters cubed) were slightly below 1.0 in the river and slightly higher in the estuary. Amphipods and capelin eggs were important constituents in the diet in the estuary, Corixidae in the river. Tagging indicated a growth rate of about 0.8 mm/day in the estuary. Both tagging and the handling of marked fish retarded growth. Tagging retarded growth for approximately 20 days. Tagging returns indicated a population of between 700 and 2500 fish near the mouth of the estuary in June and July 1961. These were thought to be remnants of the spring smolt run. In addition there was a small resident population of salmon parr living in the estuary. Numbers of fish in the estuary changed considerably from year to year.

scholarly journals The effect of ions on the motion of an oil slug through a charged capillary

2018 ◽  
Vol 841 ◽  
pp. 310-350 ◽  
Author(s):  
Z. M. Wilmott ◽  
C. J. W. Breward ◽  
S. J. Chapman
Keyword(s):  
Thin Film ◽  
Capillary Tube ◽  
Saline Water ◽  
Applied Pressure ◽  
Experimental Studies ◽  
Water Layer ◽  
Mass Action ◽  
Ionic Exchange ◽  
Pore Throat ◽  
Low Salinity

Numerous experimental studies have documented that injecting low-salinity water into an oil reservoir can increase the amount of oil recovered. However, owing to the complexity of the chemical interactions involved in this process, there has been much debate over the dominant mechanism causing this effect. In order to further understand one proposed mechanism, multicomponent ionic exchange, we study the motion of an oil slug through a clay pore throat filled with saline water. The pore throat is modelled as a capillary tube connecting two bulk regions of water. We assume that the surfaces of the oil and the capillary are negatively charged and that, due to repulsion between these surfaces, the oil slug is separated from the capillary surface by a thin film of water. Ion interactions at the oil–water and clay–water interfaces are modelled using the law of mass action. By using lubrication theory to describe the thin-film flow in the water layer separating the oil from the clay surface, and the macroscopic flow through the capillary, we derive expressions for the thickness of the wetting film, and the velocity of the oil slug, given a pressure difference across the ends of the capillary. Numerical results show that the thickness of the water layer and the velocity of the oil slug increase as the salinity of the water is reduced, suggesting that this mechanism contributes to the low-salinity effect. An analytical solution is presented in the limit in which the applied pressure is small.

scholarly journals Assessing the role of dust deposition on phytoplankton ecophysiology and succession in a low-nutrient low-chlorophyll ecosystem: a mesocosm experiment in the Mediterranean Sea

2013 ◽  
Vol 10 (5) ◽  
pp. 2973-2991 ◽  
Author(s):  
V. Giovagnetti ◽  
C. Brunet ◽  
F. Conversano ◽  
F. Tramontano ◽  
I. Obernosterer ◽  
...  
Keyword(s):  
Surface Water ◽  
Mediterranean Sea ◽  
Phytoplankton Community ◽  
Phytoplankton Bloom ◽  
Water Layer ◽  
Surface Water Layer ◽  
Saharan Dust ◽  
Dust Deposition ◽  
Pigment Analysis ◽  
The Mediterranean

Abstract. In this study, we investigate the response of the phytoplankton community, with emphasis on ecophysiology and succession, after two experimental additions of Saharan dust in the surface water layer of a low-nutrient low-chlorophyll ecosystem in the Mediterranean Sea. Three mesocosms were amended with evapocondensed dust to simulate realistic Saharan dust events, while three additional mesocosms were kept unamended and served as controls. The experiment consisted in two consecutive dust additions and samples were daily collected at different depths (−0.1, −5 and −10 m) during one week, starting before each addition occurred. Data concerning HPLC pigment analysis on two size classes (< 3 and > 3 μm), electron transport rate (ETR) vs. irradiance curves, non-photochemical fluorescence quenching (NPQ) and phytoplankton cell abundance (measured by flow cytometry), are presented and discussed in this paper. Results show that picophytoplankton mainly respond to the first dust addition, while the second addition leads to an increase of both pico- and nano-/microphytoplankton. Ecophysiological changes in the phytoplankton community occur, with NPQ and pigment concentration per cell increasing after dust additions. While biomass increases after pulses of new nutrients, ETR does not greatly vary between dust-amended and control conditions, in relation with ecophysiological changes within the phytoplankton community, such as the increase in NPQ and pigment cellular concentration. A quantitative assessment and parameterisation of the onset of a phytoplankton bloom in a nutrient-limited ecosystem is attempted on the basis of the increase in phytoplankton biomass observed during the experiment. The results of this study are discussed focusing on the adaptation of picophytoplankton to nutrient limitation in the surface water layer, as well as on size-dependent competition ability in phytoplankton.

Behaviour of iron and manganese in the Yarra estuary

1980 ◽  
Vol 31 (5) ◽  
pp. 597 ◽  
Author(s):  
M Ellaway ◽  
R Beckett ◽  
BT Hart
Keyword(s):  
Surface Water ◽  
Surface Waters ◽  
Saline Water ◽  
River Flows ◽  
River Inflow ◽  
Low Salinity ◽  
Bottom Waters ◽  
Stratified Estuary ◽  
Yarra River ◽  
Iron And Manganese

The behaviour of iron and manganese in the Yarra estuary (a rather small, well-stratified estuary) is shown to be closely linked with the magnitude of the Yarra River inflow. When river flows are average to high, the filterable metals are present largely in bound or non-ion- exchangeable forms (iron > 90%, manganese 70-80%). Filterable iron levels in surface water from the estuary decreased with increasing salinity, and the filterable manganese levels firstly increased in the upper, low-salinity region of the estuary and then decreased with increasing salinity. Possible reasons for these changes are discussed. When low river flows existed, the concentration of filterable iron and manganese both increased markedly in the bottom, saline water of the estuary. Mixing of small amounts of these enriched bottom waters with outflowing surface waters resulted in the concentrations of filterable metal in surface water increasing with increasing salinity.

Environmental change across the onset of the Messinian salinity crisis in the northern Mediterranean (Piedmont Basin, NW Italy)

2021 ◽  
Author(s):  
Mathia Sabino ◽  
Marcello Natalicchio ◽  
Daniel Birgel ◽  
Francesco Dela Pierre ◽  
Jörn Peckmann
Keyword(s):  
Water Column ◽  
Environmental Conditions ◽  
Organic Geochemistry ◽  
Water Layer ◽  
Global Ocean ◽  
Messinian Salinity Crisis ◽  
Climate Conditions ◽  
Physicochemical Changes ◽  
The Mediterranean ◽  
Nw Italy

&lt;p&gt;In the late Miocene, the Mediterranean Basin became a restricted basin because of its progressive tectonic isolation from the Global Ocean. The almost complete halt of the Atlantic-Mediterranean water exchange about 6 Ma ago triggered the deposition of the Mediterranean Salt Giant during the Messinian salinity crisis (MSC; 5.97-5.33 Ma). The environmental conditions, which developed at the onset and during the MSC, are still debated since the evaporites buried beneath the modern Mediterranean seafloor are mostly inaccessible and the marginal successions contain scarce or no body fossils. Aiming to improve our knowledge on the environmental conditions at the onset of the MSC, we investigated the sedimentary record of intermediate palaeobathymetric settings (200-1000 m) from the Piedmont Basin (NW Italy) through a multidisciplinary approach (petrography, organic geochemistry). Shale/marl couplets deposited after the MSC onset are lateral time equivalents of shallow water (&lt;200 m) shale/gypsum couplets deposited during the first phase of the crisis (5.97-5.60 Ma). Our results suggest that the MSC onset coincided with an intensification of water column stratification, most likely favoured by enhanced freshwater input due to moister climate conditions. No evidence of hypersaline conditions was found at the onset of the crisis, but rather normal marine conditions seem to have persisted at least in the upper water column, influenced by freshwater discharge. A stable chemocline apparently separated an upper water layer from a stagnant deeper-water body typified by reducing conditions. These physicochemical changes in the water column governed the sedimentary facies distribution during the first phase of the MSC.&lt;/p&gt;

scholarly journals Water Salinity Should Be Reduced for Irrigation to Minimize Its Risk of Increased Soil N2O Emissions

2018 ◽  
Vol 15 (10) ◽  
pp. 2114 ◽  
Author(s):  
Qi Wei ◽  
Junzeng Xu ◽  
Linxian Liao ◽  
Yawei Li ◽  
Haiyu Wang ◽  
...  
Keyword(s):  
Saline Water ◽  
N2o Emission ◽  
Salinity Level ◽  
N2o Emissions ◽  
Low Salinity ◽  
Nitrogen Inputs ◽  
Salinity Levels ◽  
N2o Fluxes ◽  
Moisture Dynamics ◽  
Irrigated Soils

To reveal the effect of irrigation salinity on soil nitrous oxide (N2O) emission, pot experiments were designed with three irrigation salinity levels (NaCl and CaCl2 of 1, 2.5 and 4 g/L equivalence, Ec = 3.6, 8.1 and 12.7 ds/m), either for 0 kg N/ha (N0) or 120 kg N/ha (N120) nitrogen inputs. N2O emissions from soils irrigated at different salinity levels varied in a similar pattern which was triggered by soil moisture dynamics. Yet, the magnitudes of pulse N2O fluxes were significantly varied, with the peak flux at 5 g/L irrigation salinity level being much higher than at 2 and 8 g/L. Compared to fresh water irrigated soils, cumulative N2O fluxes were reduced by 22.7% and 39.6% (N0), 29.1% and 39.2% (N120) for soils irrigated with 2 and 8 g/L saline water, while they were increased by 87.7% (N0) and 58.3% (N120) for soils irrigated with 5 g/L saline water. These results suggested that the effect degree of salinity on consumption and production of N2O might vary among irrigation salinity ranges. As such, desalinating brackish water to a low salinity level (such as 2 g/L) before it is used for irrigation might be helpful for solving water resources crises and mitigating soil N2O emissions.

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 The impact of the Messinian Salinity Crisis on marine biota

2020 ◽  
Author(s):  
Konstantina Agiadi ◽  
Niklas Hohmann ◽  
Giorgio Carnevale ◽  
Elsa Gliozzi ◽  
Constanza Faranda ◽  
...  
Keyword(s):  
Marine Mammals ◽  
Planktonic Foraminifera ◽  
Marine Ecosystem ◽  
Functional Change ◽  
Marine Biota ◽  
Messinian Salinity Crisis ◽  
Marine Fauna ◽  
Independent Evidence ◽  
The Mediterranean ◽  
The Impact

&lt;p&gt;The Messinian Salinity Crisis (MSC) was the greatest paleoenvironmental perturbation the Mediterranean has ever seen. The literature is abundant in hypotheses on the repercussions of the MSC on organisms. However, all these are based on incomplete and still uncertain scenarios about the MSC evolution, as well as on the assumption that such a paleoenvironmental perturbation must have completely reset marine biota. Having prevailed for many decades now, this assumption has leaked from paleontology and geosciences to biological sciences, with numerous studies taking this scenario for granted instead of using it as a starting hypothesis to be tested. Here, we review and revise the marine fossil record across the Mediterranean from the Tortonian until the Zanclean to follow the current rules of nomenclature, correct misidentifications, and control for stratigraphic misplacements. We examine the composition of marine faunas, both taxonomically and considering the function of each group in the marine ecosystem and the transfer of energy through the marine food web. Specifically, we investigate the following functional groups: 1) primary producers, 2) secondary producers, 3) primary consumers, 4) secondary consumers, and 5) top predators. Our study includes sea grasses, phytoplankton, corals, benthic and planktonic foraminifera, bivalves, gastropods, brachiopods, echinoids, bryozoans, fishes, ostracods, and marine mammals. We calculate biodiversity indexes to provide independent evidence quantifying to what degree the marine fauna underwent:&lt;/p&gt;&lt;ol&gt;&lt;li&gt;A drop of overall regional biodiversity of the Mediterranean due to environmental stress during the Messinian.&lt;/li&gt; &lt;li&gt;A taxonomic and functional change between the Tortonian, Messinian, and the Zanclean, that is before and after the MSC, as well as during the precursor events to that actual crisis taking place after the Tortonian/Messinian boundary.&lt;/li&gt; &lt;li&gt;The onset of the present-day west-to-east decreasing gradient in species richness, which has been related to the sea temperature and productivity gradients and the distance from the Gibraltar connection to the Atlantic.&lt;/li&gt; &lt;/ol&gt;

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