Physiological energetics of the estuarine crab Hemigrapsus crenulatus (Crustacea: Decapoda: Varunidae): responses to different salinity levels

2010 ◽  
Vol 90 (2) ◽  
pp. 267-273 ◽  
Author(s):  
Mauricio Urbina ◽  
Kurt Paschke ◽  
Paulina Gebauer ◽  
Oscar R. Chaparro
Keyword(s):  
Salinity Gradient ◽  
Ingestion Rate ◽  
Assimilation Efficiency ◽  
Decapod Crustacean ◽  
Growth Potential ◽  
Low Salinity ◽  
Physiological Processes ◽  
Salinity Levels ◽  
Nitrogen Ratio ◽  
Physiological Energetics

Hemigrapsus crenulatus is an abundant and frequent decapod crustacean inhabiting estuarine environments, where it must tolerate large shifts in salinity. The present study evaluates the effect of salinity (5, 13, 21 and 30 psu) on the adult physiological processes related to the energy balance. The growth potential (SFG) and the respired oxygen:excreted nitrogen ratio were used as indices of stress. Ingestion, excretion and respiration rates showed a significant dependence on salinity, being higher at low salinities. The assimilation efficiency remained constant along the studied salinity gradient. The assimilation and ingestion rates were inversely related with the salinity. Given this scenario, the growth potential remained constant within the studied salinity gradient, as did the oxygen:nitrogen ratio. The results suggest that the increased energy losses at low salinity due to respiration and excretion are compensated by an increment in the ingestion rate, contributing to the success of H. crenulatus in dynamic habitats such as estuaries.

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 Physiological Effects of Low Salinity Exposure on Bottlenose Dolphins (Tursiops truncatus)

2020 ◽  
Vol 1 (1) ◽  
pp. 61-75 ◽  
Author(s):  
Abby M. McClain ◽  
Risa Daniels ◽  
Forrest M. Gomez ◽  
Sam H. Ridgway ◽  
Ryan Takeshita ◽  
...  
Keyword(s):  
Medical Records ◽  
Tursiops Truncatus ◽  
Bottlenose Dolphins ◽  
Blood Samples ◽  
Low Salinity ◽  
Worldwide Distribution ◽  
Salinity Levels ◽  
Seawater Environment ◽  
Future Work ◽  
Free Ranging

Bottlenose dolphins (Tursiops truncatus) have a worldwide distribution in temperate and tropical waters and often inhabit estuarine environments, indicating their ability to maintain homeostasis in low salinity for limited periods of time. Epidermal and biochemical changes associated with low salinity exposure have been documented in stranded bottlenose dolphins; however, these animals are often found severely debilitated or deceased and in poor condition. Dolphins in the U.S. Navy Marine Mammal Program travel globally, navigating varied environments comparable to those in which free-ranging dolphins are observed. A retrospective analysis was performed of medical records from 46 Navy dolphins and blood samples from 43 Navy dolphins exposed to a variety of salinity levels for different durations over 43 years (from 1967–2010). Blood values from samples collected during low salinity environmental exposure (salinity ranging from 0–30 parts per thousand (ppt) were compared to samples collected while those same animals were in a seawater environment (31–35 ppt). Epidermal changes associated with low salinity exposure were also assessed. Significant decreases in serum sodium, chloride, and calculated serum osmolality and significant increases in blood urea nitrogen and aldosterone were observed in blood samples collected during low salinity exposure. Epidermal changes were observed in 35% of the animals that spent time in low salinity waters. The prevalence of epidermal changes was inversely proportional to the level of salinity to which the animals were exposed. Future work is necessary to fully comprehend the impacts of low salinity exposure in bottlenose dolphins, but the physiological changes observed in this study will help improve our understanding of the upper limit of duration and the lower limit of salinity in which a bottlenose dolphin can maintain homeostasis.

scholarly journals Nonionic Surfactant to Enhance the Performances of Alkaline–Surfactant–Polymer Flooding with a Low Salinity Constraint

2020 ◽  
Vol 10 (11) ◽  
pp. 3752 ◽  
Author(s):  
Shabrina Sri Riswati ◽  
Wisup Bae ◽  
Changhyup Park ◽  
Asep K. Permadi ◽  
Adi Novriansyah
Keyword(s):  
Nonionic Surfactant ◽  
Oil Recovery ◽  
Anionic Surfactant ◽  
Pore Volume ◽  
Salinity Gradient ◽  
Reference Case ◽  
Low Salinity ◽  
Asp Flooding ◽  
Optimum Salinity ◽  
Alkaline Surfactant Polymer

This paper presents a nonionic surfactant in the anionic surfactant pair (ternary mixture) that influences the hydrophobicity of the alkaline–surfactant–polymer (ASP) slug within low-salinity formation water, an environment that constrains optimal designs of the salinity gradient and phase types. The hydrophobicity effectively reduced the optimum salinity, but achieving as much by mixing various surfactants has been challenging. We conducted a phase behavior test and a coreflooding test, and the results prove the effectiveness of the nonionic surfactant in enlarging the chemical applicability by making ASP flooding more hydrophobic. The proposed ASP mixture consisted of 0.2 wt% sodium carbonate, 0.25 wt% anionic surfactant pair, and 0.2 wt% nonionic surfactant, and 0.15 wt% hydrolyzed polyacrylamide. The nonionic surfactant decreased the optimum salinity to 1.1 wt% NaCl compared to the 1.7 wt% NaCl of the reference case with heavy alcohol present instead of the nonionic surfactant. The coreflooding test confirmed the field applicability of the nonionic surfactant by recovering more oil, with the proposed scheme producing up to 74% of residual oil after extensive waterflooding compared to 51% of cumulative oil recovery with the reference case. The nonionic surfactant led to a Winsor type III microemulsion with a 0.85 pore volume while the reference case had a 0.50 pore volume. The nonionic surfactant made ASP flooding more hydrophobic, maintained a separate phase of the surfactant between the oil and aqueous phases to achieve ultra-low interfacial tension, and recovered the oil effectively.

scholarly journals Chemically Mediated Microbial “Gardening” Capacity of a Seaweed Holobiont Is Dynamic

2020 ◽  
Vol 8 (12) ◽  
pp. 1893
Author(s):  
Mahasweta Saha ◽  
Shawn Dove ◽  
Florian Weinberger
Keyword(s):  
Pathogenic Bacteria ◽  
Abiotic Factors ◽  
Terrestrial Plants ◽  
Beneficial Bacteria ◽  
Low Salinity ◽  
Aquatic Flora ◽  
Salinity Levels ◽  
Microbe Interactions ◽  
Host Microbe Interactions ◽  
Over Time

Terrestrial plants are known to “garden” the microbiota of their rhizosphere via released metabolites (that can attract beneficial microbes and deter pathogenic microbes). Such a “gardening” capacity is also known to be dynamic in plants. Although microbial “gardening” has been recently demonstrated for seaweeds, we do not know whether this capacity is a dynamic property in any aquatic flora like in terrestrial plants. Here, we tested the dynamic microbial “gardening” capacity of seaweeds using the model invasive red seaweed Agarophyton vermiculophyllum. Following an initial extraction of surface-associated metabolites (immediately after field collection), we conducted a long-term mesocosm experiment for 5 months to test the effect of two different salinities (low = 8.5 and medium = 16.5) on the microbial “gardening” capacity of the alga over time. We tested “gardening” capacity of A. vermiculophyllum originating from two different salinity levels (after 5 months treatments) in settlement assays against three disease causing pathogenic bacteria and seven protective bacteria. We also compared the capacity of the alga with field-collected samples. Abiotic factors like low salinity significantly increased the capacity of the alga to deter colonization by pathogenic bacteria while medium salinity significantly decreased the capacity of the alga over time when compared to field-collected samples. However, capacity to attract beneficial bacteria significantly decreased at both tested salinity levels when compared to field-collected samples. Dynamic microbial “gardening” capacity of a seaweed to attract beneficial bacteria and deter pathogenic bacteria is demonstrated for the first time. Such a dynamic capacity as found in the current study could also be applicable to other aquatic host–microbe interactions. Our results may provide an attractive direction of research towards manipulation of salinity and other abiotic factors leading to better defended A. vermiculophyllum towards pathogenic bacteria thereby enhancing sustained production of healthy A. vermiculophyllum in farms.

scholarly journals Large seasonal and spatial variation in nano- and microphytoplankton diversity along a Baltic Sea—North Sea salinity gradient

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Malin Olofsson ◽  
James G. Hagan ◽  
Bengt Karlson ◽  
Lars Gamfeldt
Keyword(s):  
Community Structure ◽  
Temporal Variation ◽  
High Salinity ◽  
Salinity Gradient ◽  
Seasonal Succession ◽  
Phytoplankton Diversity ◽  
Cell Abundance ◽  
Low Salinity ◽  
Spatio Temporal ◽  
The Impact

Abstract Aquatic phytoplankton experience large fluctuations in environmental conditions during seasonal succession and across salinity gradients, but the impact of this variation on their diversity is poorly understood. We examined spatio-temporal variation in nano- and microphytoplankton (> 2 µm) community structure using almost two decades of light-microscope based monitoring data. The dataset encompasses 19 stations that span a salinity gradient from 2.8 to 35 along the Swedish coastline. Spatially, both regional and local phytoplankton diversity increased with broad-scale salinity variation. Diatoms dominated at high salinity and the proportion of cyanobacteria increased with decreasing salinity. Temporally, cell abundance peaked in winter-spring at high salinity but in summer at low salinity. This was likely due to large filamentous cyanobacteria blooms that occur in summer in low salinity areas, but which are absent in higher salinities. In contrast, phytoplankton local diversity peaked in spring at low salinity but in fall and winter at high salinity. Whilst differences in seasonal variation in cell abundance were reasonably well-explained by variation in salinity and nutrient availability, variation in local-scale phytoplankton diversity was poorly predicted by environmental variables. Overall, we provide insights into the causes of spatio-temporal variation in coastal phytoplankton community structure while also identifying knowledge gaps.

scholarly journals Growth, tolerance to low ­salinity, and osmoregulation in decapod crustacean larvae

2011 ◽  
Vol 12 (3) ◽  
pp. 249-260 ◽  
Author(s):  
G Torres ◽  
L Giménez ◽  
K Anger
Keyword(s):  
Decapod Crustacean ◽  
Low Salinity

Salinity tolerances of three succulent halophytes (Tecticornia spp.) differentially distributed along a salinity gradient

2016 ◽  
Vol 43 (8) ◽  
pp. 739 ◽  
Author(s):  
Louis Moir-Barnetson ◽  
Erik J. Veneklaas ◽  
Timothy D. Colmer
Keyword(s):  
Growth Rates ◽  
Shoot Growth ◽  
High Salinity ◽  
Salt Lake ◽  
Salinity Gradient ◽  
Saline Soils ◽  
Low Salinity ◽  
Substrate Limitation ◽  
Extreme Salinity ◽  
Osmotic Potentials

We evaluated tolerances to salinity (10–2000 mM NaCl) in three halophytic succulent Tecticornia species that are differentially distributed along a salinity gradient at an ephemeral salt lake. The three species showed similar relative shoot and root growth rates at 10–1200 mM NaCl; at 2000 mM NaCl, T. indica subsp. bidens (Nees) K.A.Sheph and P.G.Wilson died, but T. medusa (K.A.Sheph and S.J.van Leeuwen) and T. auriculata (P.G.Wilson) K.A.Sheph and P.G.Wilson survived but showed highly diminished growth rates and were at incipient water stress. The mechanisms of salinity tolerance did not differ among the three species and involved the osmotic adjustment of succulent shoot tissues by the accumulation of Na+, Cl– and the compatible solute glycinebetaine, and the maintenance of high net K+ to Na+ selectivity to the shoot. Growth at extreme salinity was presumably limited by the capacity for vacuolar Na+ and Cl– uptake to provide sufficiently low tissue osmotic potentials for turgor-driven growth. Tissue sugar concentrations were not reduced at high salinity, suggesting that declines in growth would not have been caused by inadequate photosynthesis and substrate limitation compared with plants at low salinity. Equable salt tolerance among the three species up to 1200 mM NaCl means that other factors are likely to contribute to species composition at sites with salinities below this level. The lower NaCl tolerance threshold for survival in T. indica suggests that this species would be competitively inferior to T. medusa and T. auriculata in extremely saline soils.

scholarly journals Insignificant enhancement of export flux in the highly productive Subtropical Front, east of New Zealand: a high resolution study of particle export fluxes based on <sup>234</sup>Th:<sup>238</sup>U disequilibria

2011 ◽  
Vol 8 (5) ◽  
pp. 9535-9576
Author(s):  
K. Zhou ◽  
S. D. Nodder ◽  
M. Dai ◽  
J. A. Hall
Keyword(s):  
New Zealand ◽  
Salinity Gradient ◽  
Salinity Range ◽  
Water Type ◽  
Export Flux ◽  
Low Salinity ◽  
Iron Fertilization ◽  
Natural Iron ◽  
Poc Export ◽  
Particle Export

Abstract. We evaluated the downward Particulate Organic Carbon (POC) export fluxes in the Subtropical Frontal zone (STF) of the Southern Ocean. The site is characterized by enhanced primary productivity which has been suggested to be stimulated through so-called natural iron fertilization processes at its northern boundary where iron-depleted subantarctic water (SAW) mixes with oligotrophic, iron-replete subtropical water (STW). We adopted the small-volume 234Th method to achieve highest spatial sampling resolution as possible based on a cruise to the STF to the east New Zealand in austral late autumn-early winter, May–June 2008. The inventories of fluorescence, particulate 234Th and POC observed in the upper 100 m were all elevated in the mid-salinity part of the water type (34.5<S<34.8), compared with low (S<34.5) and high (S>34.8) salinity waters. However, Steady-State 234Th fluxes were similar cross all of the salinity gradient being 1484 in the mid-salinity, and 1761 and 1304 dpm m−2 d−1 in the high and low salinity zones respectively. Bottle POC/Th ratios at the depth of 100 m were used to convert the Th fluxes into POC export flux. The POC flux was again not enhanced in the mid-salinity range where the primary production was highest, being 7.4 mmol C m−2 d−1 as compared to 9.9 mmol C m−2 d−1 in high salinity waters, and 5.9 mmol C m−2 d−1 in low salinity waters. This study implied that natural iron fertilization does not necessarily lead to the enhancement of POC export in STF regions.

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