scholarly journals Salinity and its variability in the Lagoon of Venice, 2000–2009

2014 ◽  
Vol 5 (1) ◽  
pp. 41 ◽  
Author(s):  
Alberto Zirino ◽  
Hany Elwany ◽  
Carlos Neira ◽  
Francesco Maicu ◽  
Guillermo Mendoza ◽  
...  
Keyword(s):  
Steady State ◽  
Venice Lagoon ◽  
Intermediate Zone ◽  
Lagoon Of Venice ◽  
Salinity Change ◽  
Salinity Distribution ◽  
Rainfall Events ◽  
Salinity Changes ◽  
Salinity Data

Yearly averages computed from monthly and bimonthly salinity data collected between 2000 and 2009 from 13 broadly spaced stations in the Venice Lagoon were analysed in view of 30 min data collected semi-continuously during 2009 at nine similarly located stations. Data from all stations and all years indicate that, based on yearly averages, the lagoon may be divided along its major (long) axis into three areas: 1) a northern, freshwater impacted area (S = 32 PSU of low, tidally-caused, variability, and 3) an intermediate zone. Salinity changes are closely associated with rainfall events, and the incoming freshwater is consistently distributed throughout the lagoon by tidal action. Much variability is simply a result of the forward and backward motion of the tides and is not caused by a salinity change in the water itself. The consistency of the 2000–2009 data and the historical (to 1961) watershed record support the hypothesis that the Venice Lagoon has been and is currently at steady-state with respect to its salinity distribution. As such, it is conducive to the development of (at least) three separate ecosystems.

scholarly journals Assessing glyphosate in water, marine particulate matter, and sediments in the Lagoon of Venice

2021 ◽  
Author(s):  
Matteo Feltracco ◽  
Elena Barbaro ◽  
Elisa Morabito ◽  
Roberta Zangrando ◽  
Rossano Piazza ◽  
...  
Keyword(s):  
Particulate Matter ◽  
Suspended Particulate Matter ◽  
Water Environment ◽  
Venice Lagoon ◽  
Lagoon Of Venice ◽  
Agricultural Chemicals ◽  
Sediment Samples ◽  
Lagoon Water ◽  
Pollution Levels ◽  
Suspended Particulate

Abstract Lagoon water, suspended particulate matter, and sediment samples from seven sites at Lagoon of Venice were collected from 2019 to 2021 in order to study the presence of the herbicide glyphosate (N-(phosphonomethyl)glycine), among the most widely used agricultural chemicals worldwide, but its occurrence in lagoon water environment has not been deeply investigated. The sites were selected considering a supposed diversity of inputs and of pollution levels. An analytical method based on ion chromatography coupled with tandem mass spectrometry was optimized and validated for lagoon water, marine particulate matter, and sediment samples. Maximum concentrations of glyphosate were 260 and 7 ng L−1 for lagoon water and suspended particulate matter, respectively, and 15 ng g−1 for sediment, with some spatial and temporal fluctuations. Our results demonstrate that glyphosate content in the Venice Lagoon mainly depends on external forcing from river inlets and agricultural lagoon activities.

scholarly journals Use of Thermodynamic Orientors to Assess the Efficiency of Ecosystems: A Case Study in the Lagoon of Venice

2002 ◽  
Vol 2 ◽  
pp. 255-260 ◽  
Author(s):  
Simone Bastianoni
Keyword(s):  
Aquatic Ecosystems ◽  
Fish Farming ◽  
Venice Lagoon ◽  
Ecological Systems ◽  
Actual State ◽  
Lagoon Of Venice ◽  
The Past ◽  
Comparison Results ◽  
The One

So-called orientors have been introduced at the interface between ecology and thermodynamics. Two have been chosen here to compare the characteristics of five ecological systems: exergy, which is related to the degree of organization of a system and represents the biogeochemical energy of a system, and emergy, which is defined as the total amount of solar energy directly or indirectly required to generate a product or a service. They represent two complementary aspects of a system: the actual state and the past work needed to reach that state. The ratio of exergy to the emergy flow indicates the efficiency of an ecosystem in producing or maintaining its organization.The main system under study is a portion of the Venice Lagoon, which is used as a fish farming basin. Four other aquatic ecosystems were considered for comparison. Results show that the ecosystem within the Venice Lagoon is the one with the highest efficiency in transforming the available inputs in organization of the system. This fact is due to human intervention, which is very limited but also very effective.

scholarly journals Global-scale patterns of observed sea surface salinity intensified since the 1870s

2021 ◽  
Vol 2 (1) ◽  
Author(s):  
W. John Gould ◽  
Stuart A. Cunningham
Keyword(s):  
Hydrological Cycle ◽  
Global Scale ◽  
Sea Surface ◽  
Sea Surface Salinity ◽  
Salinity Change ◽  
Surface Salinity ◽  
Salinity Changes ◽  
Change Pattern ◽  
The World ◽  
Global Mean

AbstractSea surface salinity patterns have intensified between the mid-20th century and present day, with saline areas becoming saltier and fresher areas fresher. This change has been linked to a human-induced strengthening of the global hydrological cycle as global mean surface temperatures rose. Here we analyse salinity observations from the round-the-world voyages of HMS Challenger and SMS Gazelle in the 1870s, early in the industrial era, to reconstruct surface salinity changes since that decade. We find that the amplification of the salinity change pattern between the 1870s and the 1950s was at a rate that was 54 ± 10% lower than the post-1950s rate. The acceleration in salinity pattern amplification over almost 150 years implies that the hydrological cycle would have similarly accelerated over this period.

scholarly journals Hemocyte Responses of the Oyster Crassostrea hongkongensis Exposed to Diel-Cycling Hypoxia and Salinity Change

2021 ◽  
Vol 8 ◽  
Author(s):  
Zhe Xie ◽  
Shuaishuai Wei ◽  
Haomiao Dong ◽  
Hui Chen ◽  
Qianqian Zhang ◽  
...  
Keyword(s):  
Hong Kong ◽  
Immune Function ◽  
Summer Season ◽  
Mass Mortality ◽  
Combined Stress ◽  
Salinity Change ◽  
Salinity Fluctuation ◽  
Crassostrea Hongkongensis ◽  
Low Salinity ◽  
Salinity Changes

Marine hypoxia caused by nutrient enrichment in coastal waters has become a global problem for decades, especially diel-cycling hypoxia that occurs frequently in the summer season. On the contrary, sudden rainstorms, and freshwater discharge make salinity in estuarine and coastal ecosystems variable, which often occurs with hypoxia. We found mass mortality of the Hong Kong oyster Crassostrea hongkongensis in the field where hypoxia and salinity fluctuation co-occur in the summer season during the past several years. To investigate the effects of diel-cycling hypoxia and salinity changes on the hemocyte immune function of C. hongkongensis, oysters were exposed to a combined effect of two dissolved oxygen (DO) concentrations (24 h normal oxygen 6 mg/L, 12 h normal oxygen 6 mg/L, and 12 h hypoxia 2 mg/L) and three salinities (10, 25, and 35‰) for 14 days. Subsequently, all treatments were restored to constant normal oxygen (6 mg/L) and salinity under 25‰ for 3 days to study the recovery of hemocyte immune function from the combined stress. Hemocyte parameters were analyzed by flow cytometry, including hemocyte mortality (HM), total hemocyte count (THC), phagocytosis (PHA), esterase (EST) activity, reactive oxygen species (ROS), lysosomal content (LYSO), and mitochondrial number (MN). The experimental results showed that diel-cycling hypoxia and salinity changes have obvious interactive effects on various immune parameters. In detail, diel-cycling hypoxia and decreases in salinity led to increased HM, and low salinity caused heavier impacts. In addition, low salinity, and diel-cycling hypoxia also led to decreases in LYSO, EST, and THC, while the decrease of PHA only occurs in the early stage. On the contrary, ROS production increased significantly under low salinity and hypoxic conditions. After 3-day recovery, THC, PHA, EST, LYSO, and MN were basically restored to normal, while HM and ROS were still significantly affected by diel-cycling hypoxia and salinity change, indicating that the combined stress of diel-cycling hypoxia and salinity changes had latent effects on the immune function of C. hongkongensis. Our results highlight that diel-cycling hypoxia and salinity change may impair the health and survival of the Hong Kong oyster C. hongkongensis and may be the key factors for the mass mortality of this oyster in the field.

scholarly journals Maintenance and Broadening of the Ocean’s Salinity Distribution by the Water Cycle

2015 ◽  
Vol 28 (24) ◽  
pp. 9550-9560 ◽  
Author(s):  
Jan D. Zika ◽  
Nikolaos Skliris ◽  
A. J. George Nurser ◽  
Simon A. Josey ◽  
Lawrence Mudryk ◽  
...  
Keyword(s):  
Steady State ◽  
Simple Model ◽  
Time Scale ◽  
Hydrological Cycle ◽  
Water Cycle ◽  
Ocean Model ◽  
Salinity Distribution ◽  
Fresh Waters ◽  
Ocean Salinity ◽  
Saline Waters

Abstract The global water cycle leaves an imprint on ocean salinity through evaporation and precipitation. It has been proposed that observed changes in salinity can be used to infer changes in the water cycle. Here salinity is characterized by the distribution of water masses in salinity coordinates. Only mixing and sources and sinks of freshwater and salt can modify this distribution. Mixing acts to collapse the distribution, making saline waters fresher and fresh waters more saline. Hence, in steady state, there must be net precipitation over fresh waters and net evaporation over saline waters. A simple model is developed to describe the relationship between the breadth of the distribution, the water cycle, and mixing—the latter being characterized by an e-folding time scale. In both observations and a state-of-the-art ocean model, the water cycle maintains a salinity distribution in steady state with a mixing time scale of the order of 50 yr. The same simple model predicts the response of the salinity distribution to a change in the water cycle. This study suggests that observations of changes in ocean salinity could be used to infer changes in the hydrological cycle.

Steady-State Levels of Monoamines in the Rat Lumbar Spinal Cord: Spatial Mapping and the Effect of Acute Spinal Cord Injury

2004 ◽  
Vol 92 (1) ◽  
pp. 567-577 ◽  
Author(s):  
Brian R. Noga ◽  
Alberto Pinzon ◽  
Riza P. Mesigil ◽  
Ian D. Hentall
Keyword(s):  
Spinal Cord ◽  
Steady State ◽  
Spinal Injury ◽  
Intermediate Zone ◽  
Lumbar Spinal Cord ◽  
Thoracic Spinal Cord ◽  
Thoracic Spinal ◽  
Cord Injury ◽  
Locomotor Rhythms ◽  
Lumbar Spinal

Monoamines in the spinal cord are important in the regulation of locomotor rhythms, nociception, and motor reflexes. To gain further insight into the control of these functions, the steady-state extracellular distribution of monoamines was mapped in the anesthetized rat's lumbar spinal cord. The effect of acute spinal cord lesions at sites selected for high resting levels was determined over ∼1 h to estimate contributions to resting levels from tonic descending activity and to delineate chemical changes that may influence the degree of pathology and recovery after spinal injury. Measurements employed fast cyclic voltammetry with carbon fiber microelectrodes to give high spatial resolution. Monoamine oxidation currents, sampled at equal vertical spacings within each segment, were displayed as contours over the boundaries delineated by histologically reconstructed electrode tracks. Monoamine oxidation currents were found in well defined foci, often confined within a single lamina. Larger currents were typically found in the dorsal or ventral horns and in the lateral aspect of the intermediate zone. Cooling of the low-thoracic spinal cord led to a decrease in the oxidation current (to 71–85% of control) in dorsal and ventral horns. Subsequent low-thoracic transection produced a transient increase in signal in some animals followed by a longer lasting decrease to levels similar to or below that with cooling (to 17–86% of control values). We conclude that descending fibers tonically release high amounts of monoamines in localized regions of the dorsal and ventral horn of the lumbar spinal cord at rest. Lower amounts of monoamines were detected in medial intermediate zone areas, where strong release may be needed for descending activation of locomotor rhythms.

scholarly journals Spatial and Temporal Changes of Tidal Inlet Using Object-Based Image Analysis of Multibeam Echosounder Measurements: A Case from the Lagoon of Venice, Italy

2020 ◽  
Vol 12 (13) ◽  
pp. 2117 ◽  
Author(s):  
Lukasz Janowski ◽  
Fantina Madricardo ◽  
Stefano Fogarin ◽  
Aleksandra Kruss ◽  
Emanuela Molinaroli ◽  
...  
Keyword(s):  
Image Analysis ◽  
Methodological Approach ◽  
Venice Lagoon ◽  
Tidal Inlet ◽  
Lagoon Of Venice ◽  
Seabed Sediment ◽  
Multibeam Echosounder ◽  
Object Based Image Analysis ◽  
Object Based ◽  
Muddy Sediments

Scientific exploration of seabed substrata has significantly progressed in the last few years. Hydroacoustic methods of seafloor investigation, including multibeam echosounder measurements, allow us to map large areas of the seabed with unprecedented precision. Through time-series of hydroacoustic measurements, it was possible to determine areas with distinct characteristics in the inlets of the Lagoon of Venice, Italy. Their temporal variability was investigated. Monitoring the changes was particularly relevant, considering the presence at the channel inlets of mobile barriers of the Experimental Electromechanical Module (MoSE) project installed to protect the historical city of Venice from flooding. The detection of temporal and spatial changes was performed by comparing seafloor maps created using object-based image analysis and supervised classifiers. The analysis included extraction of 25 multibeam echosounder bathymetry and backscatter features. Their importance was estimated using an objective approach with two feature selection methods. Moreover, the study investigated how the accuracy of classification could be affected by the scale of object-based segmentation. The application of the classification method at the proper scale allowed us to observe habitat changes in the tidal inlet of the Venice Lagoon, showing that the sediment substrates located in the Chioggia inlet were subjected to very dynamic changes. In general, during the study period, the area was enriched in mixed and muddy sediments and was depleted in sandy deposits. This study presents a unique methodological approach to predictive seabed sediment composition mapping and change detection in a very shallow marine environment. A consistent, repeatable, logical site-specific workflow was designed, whose main assumptions could be applied to other seabed mapping case studies in both shallow and deep marine environments, all over the world.

scholarly journals Simulating the Role of Surface Forcing on Observed Multidecadal Upper-Ocean Salinity Changes

2016 ◽  
Vol 29 (15) ◽  
pp. 5575-5588 ◽  
Author(s):  
Véronique Lago ◽  
Susan E. Wijffels ◽  
Paul J. Durack ◽  
John A. Church ◽  
Nathaniel L. Bindoff ◽  
...  
Keyword(s):  
Water Cycle ◽  
Three Dimensional ◽  
Ocean Model ◽  
Salinity Change ◽  
Surface Salinity ◽  
Qualitative Comparison ◽  
Salinity Field ◽  
Temperature Changes ◽  
Surface Warming ◽  
Salinity Changes

Abstract The ocean’s surface salinity field has changed over the observed record, driven by an intensification of the water cycle in response to global warming. However, the origin and causes of the coincident subsurface salinity changes are not fully understood. The relationship between imposed surface salinity and temperature changes and their corresponding subsurface changes is investigated using idealized ocean model experiments. The ocean’s surface has warmed by about 0.5°C (50 yr)−1 while the surface salinity pattern has amplified by about 8% per 50 years. The idealized experiments are constructed for a 50-yr period, allowing a qualitative comparison to the observed salinity and temperature changes previously reported. The comparison suggests that changes in both modeled surface salinity and temperature are required to replicate the three-dimensional pattern of observed salinity change. The results also show that the effects of surface changes in temperature and salinity act linearly on the changes in subsurface salinity. Surface salinity pattern amplification appears to be the leading driver of subsurface salinity change on depth surfaces; however, surface warming is also required to replicate the observed patterns of change on density surfaces. This is the result of isopycnal migration modified by the ocean surface warming, which produces significant salinity changes on density surfaces.

Steady-state achievement by introduction of true tidal velocities in a pollution model of the Venice Lagoon

1987 ◽  
Vol 37 (1-2) ◽  
pp. 59-79 ◽  
Author(s):  
Camillo Dejak ◽  
Ileana Mazzei Lalatta ◽  
Ettore Messina ◽  
Giovanni Pecenik
Keyword(s):  
Steady State ◽  
Venice Lagoon
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