scholarly journals Effect of dredging activities on the health status of Posidonia oceanica meadows along the north Latium coast (Tyrrhenian Sea)

2015 ◽  
Author(s):  
Valentina Gnisci ◽  
Simone Bonamano ◽  
Carla Micheli ◽  
Selvaggia Cognetti de Martiis ◽  
Viviana Piermattei ◽  
...  
Keyword(s):  
Health Status ◽  
Sedimentation Rate ◽  
Numerical Models ◽  
Posidonia Oceanica ◽  
Shoot Density ◽  
Habitats Directive ◽  
Tyrrhenian Sea ◽  
High Concentration ◽  
The North ◽  
Shoot Number

Coastal areas are characterized by several disturbances due to the presence of numerous anthropic activities that may alter the health status and ecological functioning of Posidonia oceanica meadows. The reduction of seawater transparency and the increase of sedimentation rate are among the main causes of their regression. This work is focused on the northern Latium coast (Central Tyrrhenian Sea), from Marina di Tarquinia to Santa Severa. Over time, alteration of river run-off (change in land use, captation along rivers, etc.) and dredging activities carried out within the Civitavecchia harbour, have led to the dispersion of a large amount of fine materials in the marine environment. In this area, four Sites of Community Importance were identified according to the Habitats Directive (92/43/EEC), due to the presence of P. oceanica beds. Meadows are fragmented and discontinuous also because the high geomorphological heterogeneity. The aim of this work has been to evaluate the effects of the reduction of seawater transparency and the alteration of sedimentation rate on the meadows due to dredging activities. The evaluation of meadows health status from 2002 to 2013 was performed by structural (shoot density and coverage) and functional (leaf biometry) standard descriptors analysis. In the same period, the water transparency and the sedimentation rate have been analysed using numerical models able to distinguish between river and dredging contributions. The simulations of dredged sediments transport have highlighted as the plume is transported mainly to the north, with high concentration values near the shoreline; for this reason the evaluations of shoot density of P. oceanica meadows located near the harbour and far from the coast have not shown a decrease over the years. In the meadow further north, where the concentration of dredged suspended materials is decreasing, the reduction in shoot number is mainly due to the sediment plumes of the Marta and Mignone rivers.

scholarly journals Effect of dredging activities on the health status of Posidonia oceanica meadows along the north Latium coast (Tyrrhenian Sea)

2015 ◽  
Author(s):  
Valentina Gnisci ◽  
Simone Bonamano ◽  
Carla Micheli ◽  
Selvaggia Cognetti de Martiis ◽  
Viviana Piermattei ◽  
...  
Keyword(s):  
Health Status ◽  
Sedimentation Rate ◽  
Numerical Models ◽  
Posidonia Oceanica ◽  
Shoot Density ◽  
Habitats Directive ◽  
Tyrrhenian Sea ◽  
High Concentration ◽  
The North ◽  
Shoot Number

Coastal areas are characterized by several disturbances due to the presence of numerous anthropic activities that may alter the health status and ecological functioning of Posidonia oceanica meadows. The reduction of seawater transparency and the increase of sedimentation rate are among the main causes of their regression. This work is focused on the northern Latium coast (Central Tyrrhenian Sea), from Marina di Tarquinia to Santa Severa. Over time, alteration of river run-off (change in land use, captation along rivers, etc.) and dredging activities carried out within the Civitavecchia harbour, have led to the dispersion of a large amount of fine materials in the marine environment. In this area, four Sites of Community Importance were identified according to the Habitats Directive (92/43/EEC), due to the presence of P. oceanica beds. Meadows are fragmented and discontinuous also because the high geomorphological heterogeneity. The aim of this work has been to evaluate the effects of the reduction of seawater transparency and the alteration of sedimentation rate on the meadows due to dredging activities. The evaluation of meadows health status from 2002 to 2013 was performed by structural (shoot density and coverage) and functional (leaf biometry) standard descriptors analysis. In the same period, the water transparency and the sedimentation rate have been analysed using numerical models able to distinguish between river and dredging contributions. The simulations of dredged sediments transport have highlighted as the plume is transported mainly to the north, with high concentration values near the shoreline; for this reason the evaluations of shoot density of P. oceanica meadows located near the harbour and far from the coast have not shown a decrease over the years. In the meadow further north, where the concentration of dredged suspended materials is decreasing, the reduction in shoot number is mainly due to the sediment plumes of the Marta and Mignone rivers.

scholarly journals Assessment of Posidonia oceanica status along the north Croatian coast (Adriatic Sea)

2015 ◽  
Author(s):  
Ivan Guala ◽  
Ljiljana Iveša ◽  
Patrik Krstinić ◽  
Zrinka Jakl ◽  
Milena Šijan ◽  
...  
Keyword(s):  
Lower Limit ◽  
Adriatic Sea ◽  
Posidonia Oceanica ◽  
Shoot Density ◽  
Monitoring Programme ◽  
Habitats Directive ◽  
Anthropogenic Factors ◽  
Northern Adriatic ◽  
National Monitoring ◽  
The North

Monitoring of Posidonia oceanica was carried out in the framework of the MedMPAnet Project in eight meadows not formerly explored in an area along the north coast of Croatia (Primorje-Gorski Kotar County, Northern Adriatic Sea). The survey was aimed to collect preliminary data as a baseline for future surveillance cycles of the priority habitat 1120 "Posidonia beds" within the framework of the National Monitoring Programme, according to the requirements of the EU Habitats Directive. Fieldwork was carried out in 2013 and 2014 through direct SCUBA diving surveys. At each site, general information on coastal features and potential human pressures was recorded and the following descriptors of meadow conditions were assessed at three depth ranges: shoot density, percent coverage of Posidonia oceanica, dead matte and substrate type; depth and type of lower limits were also recorded for each meadow. Two meadows, located in the island of Rab (Uvala Planka and Frkanj), were investigated during both years of survey in order to test any differences due to the methodological approach we used. Overall, results indicated signs of distress for several meadows. Density ranged from 355±22 to 629±21 shoot per m2 at shallow stations (<10 m depth), from 141±8 to 324±23 shoot per m2 at intermediate depth (about 15 m), and from 79±5 to 157±10 shoot per m2 at the lower limit. Regression was also testified by high coverage of dead matte (locally >40%) especially at the lower limit, which was regressive in four meadows and in no case did it exceed 27 meters in depth. The temporal comparison provided consistent results between the two years for investigation of shoot density, at all sites and throughout the bathymetric range. However, some changes were detected in the deepest portions of both meadows in the coverage of Posidonia oceanica (lower than 50% in 2014). Further monitoring and research campaigns are recommended to improve the level of knowledge on the status of meadows in this area, to develop a baseline for assessing trends on a long-term temporal scale as requested by Habitats Directive, and to shed light on the relevance of both environmental and anthropogenic factors in determining the health status of the meadows. Intercalibration among operators is also suggested to ensure reliable data in implementing the National Monitoring Programme.

scholarly journals Assessment of Posidonia oceanica status along the north Croatian coast (Adriatic Sea)

2015 ◽  
Author(s):  
Ivan Guala ◽  
Ljiljana Iveša ◽  
Patrik Krstinić ◽  
Zrinka Jakl ◽  
Milena Šijan ◽  
...  
Keyword(s):  
Lower Limit ◽  
Adriatic Sea ◽  
Posidonia Oceanica ◽  
Shoot Density ◽  
Monitoring Programme ◽  
Habitats Directive ◽  
Anthropogenic Factors ◽  
Northern Adriatic ◽  
National Monitoring ◽  
The North

Monitoring of Posidonia oceanica was carried out in the framework of the MedMPAnet Project in eight meadows not formerly explored in an area along the north coast of Croatia (Primorje-Gorski Kotar County, Northern Adriatic Sea). The survey was aimed to collect preliminary data as a baseline for future surveillance cycles of the priority habitat 1120 "Posidonia beds" within the framework of the National Monitoring Programme, according to the requirements of the EU Habitats Directive. Fieldwork was carried out in 2013 and 2014 through direct SCUBA diving surveys. At each site, general information on coastal features and potential human pressures was recorded and the following descriptors of meadow conditions were assessed at three depth ranges: shoot density, percent coverage of Posidonia oceanica, dead matte and substrate type; depth and type of lower limits were also recorded for each meadow. Two meadows, located in the island of Rab (Uvala Planka and Frkanj), were investigated during both years of survey in order to test any differences due to the methodological approach we used. Overall, results indicated signs of distress for several meadows. Density ranged from 355±22 to 629±21 shoot per m2 at shallow stations (<10 m depth), from 141±8 to 324±23 shoot per m2 at intermediate depth (about 15 m), and from 79±5 to 157±10 shoot per m2 at the lower limit. Regression was also testified by high coverage of dead matte (locally >40%) especially at the lower limit, which was regressive in four meadows and in no case did it exceed 27 meters in depth. The temporal comparison provided consistent results between the two years for investigation of shoot density, at all sites and throughout the bathymetric range. However, some changes were detected in the deepest portions of both meadows in the coverage of Posidonia oceanica (lower than 50% in 2014). Further monitoring and research campaigns are recommended to improve the level of knowledge on the status of meadows in this area, to develop a baseline for assessing trends on a long-term temporal scale as requested by Habitats Directive, and to shed light on the relevance of both environmental and anthropogenic factors in determining the health status of the meadows. Intercalibration among operators is also suggested to ensure reliable data in implementing the National Monitoring Programme.

scholarly journals Assessment of Posidonia oceanica status along the north Croatian coast (Adriatic Sea)

2015 ◽  
Author(s):  
Ivan Guala ◽  
Ljiljana Iveša ◽  
Patrik Krstinić ◽  
Zrinka Jakl ◽  
Milena Šijan ◽  
...  
Keyword(s):  
Lower Limit ◽  
Adriatic Sea ◽  
Posidonia Oceanica ◽  
Shoot Density ◽  
Monitoring Programme ◽  
Habitats Directive ◽  
Anthropogenic Factors ◽  
Northern Adriatic ◽  
National Monitoring ◽  
The North

Monitoring of Posidonia oceanica was carried out in the framework of the MedMPAnet Project in eight meadows not formerly explored in an area along the north coast of Croatia (Primorje-Gorski Kotar County, Northern Adriatic Sea). The survey was aimed to collect preliminary data as a baseline for future surveillance cycles of the priority habitat 1120 "Posidonia beds" within the framework of the National Monitoring Programme, according to the requirements of the EU Habitats Directive. Fieldwork was carried out in 2013 and 2014 through direct SCUBA diving surveys. At each site, general information on coastal features and potential human pressures was recorded and the following descriptors of meadow conditions were assessed at three depth ranges: shoot density, percent coverage of Posidonia oceanica, dead matte and substrate type; depth and type of lower limits were also recorded for each meadow. Two meadows, located in the island of Rab (Uvala Planka and Frkanj), were investigated during both years of survey in order to test any differences due to the methodological approach we used. Overall, results indicated signs of distress for several meadows. Density ranged from 355±22 to 629±21 shoot per m2 at shallow stations (<10 m depth), from 141±8 to 324±23 shoot per m2 at intermediate depth (about 15 m), and from 79±5 to 157±10 shoot per m2 at the lower limit. Regression was also testified by high coverage of dead matte (locally >40%) especially at the lower limit, which was regressive in four meadows and in no case did it exceed 27 meters in depth. The temporal comparison provided consistent results between the two years for investigation of shoot density, at all sites and throughout the bathymetric range. However, some changes were detected in the deepest portions of both meadows in the coverage of Posidonia oceanica (lower than 50% in 2014). Further monitoring and research campaigns are recommended to improve the level of knowledge on the status of meadows in this area, to develop a baseline for assessing trends on a long-term temporal scale as requested by Habitats Directive, and to shed light on the relevance of both environmental and anthropogenic factors in determining the health status of the meadows. Intercalibration among operators is also suggested to ensure reliable data in implementing the National Monitoring Programme.

scholarly journals Veterinary needs of dogs in two resource-limited communities in the Gauteng and North West provinces of South Africa

2001 ◽  
Vol 72 (4) ◽  
Author(s):  
W.N. Minnaar ◽  
R.C. Krecek
Keyword(s):  
South Africa ◽  
Health Status ◽  
Body Condition ◽  
Veterinary Services ◽  
Structured Interviews ◽  
Deficient Diet ◽  
North West ◽  
The North ◽  
Resource Limited ◽  
Protein Deficient Diet

Information on the socioeconomic aspects and the health status of dogs in 2 resource-limited communities in the North West and Gauteng provinces of South Africa was gathered using semi-structured interviews and a standardised questionnaire. The dogs were examined clinically to determine their health status, and their body condition and age were scored. Most of the dogs (93 % in Jericho and 90 % in Zuurbekom) were infected with hookworm, which poses a threat to animal and human health in the 2 study areas. Many dogs were also being given a protein-deficient diet, which together with hookworm parasites would impact considerably on the dog's health. Dogs were mainly kept for security reasons. The need indicated to be most important by the residents of the 2 commnities was a lack of available and affordable veterinary services.

A generalized settling approach in the numerical modeling of sedimentation tanks

1998 ◽  
Vol 38 (3) ◽  
pp. 95-102 ◽  
Author(s):  
G. Mazzolani ◽  
F. Pirozzi ◽  
G. d'Antonoi
Keyword(s):  
Transport Model ◽  
Numerical Models ◽  
Removal Rate ◽  
Total Concentration ◽  
Suspended Solid ◽  
Primary Concern ◽  
High Concentration ◽  
Hindered Settling ◽  
Low Concentration ◽  
Solid Distribution

Numerical models for the prediction of turbulent flow field and suspended solid distribution in sedimentation tanks are characterized by refined modeling of hydrodynamics, but apparently weak modeling of settling properties of suspensions. It is known that sedimentation tanks typically treat highly heterodisperse suspensions, whose concentrations range from relatively high to low values. However, settling is modeled either by considering one or more particle classes of different settling velocity, without accounting for hindered settling conditions, or by treating the suspension as monodisperse, even in regions of low concentration. A new generalized settling model is proposed to account for both discrete settling conditions in low concentration regions of the tanks and hindered settling conditions in high concentration regions. Settling velocities of heterodisperse suspensions are then determined as a function of particle velocities in isolation and their total concentration. The settling model is used in the framework of a transport model for the simulation of hydrodynamics and solid distribution in a rectangular sedimentation tank. Results show that solid distribution is mainly affected by particle interactions in the inlet region and by settling properties of individual particles in the outlet region. Comparison of the proposed settling model with other settling models suggests that a generalized approach of the modeling of settling properties of suspensions is a primary concern to obtain reliable predictions of the removal rate.

scholarly journals Rates of consumption of atmospheric CO<sub>2</sub> through the weathering of loess during the next 100 yr of climate change

2013 ◽  
Vol 10 (1) ◽  
pp. 135-148 ◽  
Author(s):  
Y. Goddéris ◽  
S. L. Brantley ◽  
L. M. François ◽  
J. Schott ◽  
D. Pollard ◽  
...  
Keyword(s):  
Climate Change ◽  
Reaction Front ◽  
Numerical Models ◽  
Atmospheric Co2 ◽  
Co2 Production ◽  
Depth Interval ◽  
Mississippi Valley ◽  
The South ◽  
The North ◽  
The Future

Abstract. Quantifying how C fluxes will change in the future is a complex task for models because of the coupling between climate, hydrology, and biogeochemical reactions. Here we investigate how pedogenesis of the Peoria loess, which has been weathering for the last 13 kyr, will respond over the next 100 yr of climate change. Using a cascade of numerical models for climate (ARPEGE), vegetation (CARAIB) and weathering (WITCH), we explore the effect of an increase in CO2 of 315 ppmv (1950) to 700 ppmv (2100 projection). The increasing CO2 results in an increase in temperature along the entire transect. In contrast, drainage increases slightly for a focus pedon in the south but decreases strongly in the north. These two variables largely determine the behavior of weathering. In addition, although CO2 production rate increases in the soils in response to global warming, the rate of diffusion back to the atmosphere also increases, maintaining a roughly constant or even decreasing CO2 concentration in the soil gas phase. Our simulations predict that temperature increasing in the next 100 yr causes the weathering rates of the silicates to increase into the future. In contrast, the weathering rate of dolomite – which consumes most of the CO2 – decreases in both end members (south and north) of the transect due to its retrograde solubility. We thus infer slower rates of advance of the dolomite reaction front into the subsurface, and faster rates of advance of the silicate reaction front. However, additional simulations for 9 pedons located along the north–south transect show that the dolomite weathering advance rate will increase in the central part of the Mississippi Valley, owing to a maximum in the response of vertical drainage to the ongoing climate change. The carbonate reaction front can be likened to a terrestrial lysocline because it represents a depth interval over which carbonate dissolution rates increase drastically. However, in contrast to the lower pH and shallower lysocline expected in the oceans with increasing atmospheric CO2, we predict a deeper lysocline in future soils. Furthermore, in the central Mississippi Valley, soil lysocline deepening accelerates but in the south and north the deepening rate slows. This result illustrates the complex behavior of carbonate weathering facing short term global climate change. Predicting the global response of terrestrial weathering to increased atmospheric CO2 and temperature in the future will mostly depend upon our ability to make precise assessments of which areas of the globe increase or decrease in precipitation and soil drainage.

Motility and energy-rich phosphorus compounds in spermatozoa of Octopus dofleini martini

1971 ◽  
Vol 178 (1051) ◽  
pp. 151-160 ◽  
Keyword(s):  
Sea Water ◽  
Phosphorus Compounds ◽  
Short Exposure ◽  
Motile Sperm ◽  
High Concentration ◽  
Irreversible Loss ◽  
Prolonged Incubation ◽  
The North ◽  
Sperm Suspension ◽  
The North Pacific

The spermatozoa of the giant octopus of the North Pacific, freshly removed from spermatophores, showed very little motility, but on dilution with sea-water or 2.7 % NaCl, followed by dialysis against either of these two media, they became intensely motile and remained so for several days at 2 to 10 °C. At higher temperatures, particularly above 25 °C, octopus spermatozoa lost their motility rapidly. At 35 °C, complete and irreversible loss of motility occurred within less than 1 min. The motility of octopus spermatozoa at 2 to 10 °C persisted under both anaerobic and aerobic conditions and did not require the presence of exogenous glycolysable sugar. The addition of spermatophoric plasma to a motile sperm suspension inhibited motility. Other inhibitors were sodium azide, 2, 4-dinitrophenol and ethylenediaminetetra-acetate, at 0.001 M concentrations. ATP, ADP and arginine phosphate have been identified and quantitatively measured in octopus spermatozoa. On prolonged incubation of motile sperm suspensions a t 3 °C, ATP and ADP did not decline appreciably, whilst arginine phosphate decreased considerably. The decrease was even more pronounced in sperm suspensions which had first been inactivated by short exposure to 35 °C, prior to prolonged incubation at 3 °C. Glycogen, the main carbohydrate store of octopus spermatozoa, remained at a high concentration even in sperm suspensions kept for 5 days at 3 °C, and there was no appreciable difference in that respect between a sample containing motile spermatozoa and one in which, at the outset of incubation, the spermatozoa were immobilized by heating to 35 °C.

scholarly journals Tsunamis from prospected mass failure on the Marsili submarine volcano flanks and hints for tsunami hazard evaluation

2020 ◽  
Vol 83 (1) ◽  
Author(s):  
G. Gallotti ◽  
F. Zaniboni ◽  
G. Pagnoni ◽  
C. Romagnoli ◽  
F. Gamberi ◽  
...  
Keyword(s):  
Numerical Models ◽  
Hydrothermal Activity ◽  
Hazard Evaluation ◽  
Medium Size ◽  
Tyrrhenian Sea ◽  
Submarine Volcano ◽  
Case Scenario ◽  
Worst Case ◽  
Tsunami Waves ◽  
Mass Failure

AbstractThe Marsili Seamount (Tyrrhenian Sea, Italy) is the largest submarine volcano in the Mediterranean Sea, located in the middle of the Marsili Basin, facing the Calabrian and Sicilian coasts on its eastern side, and the coasts of Sardinia on the opposite side. It has erupted in historical times, and its summit crest is affected by widespread hydrothermal activity. This study looks at mass failures taking place at different depths on the flanks of the volcano and estimates their associated tsunamigenic potential. Mass failure, tsunami generation, and propagation have been simulated by means of numerical models developed by the Tsunami Research Team of the University of Bologna. In all, we consider five cases. Of these, three scenarios, one regarding a very small detachment and two medium-sized ones (between 2 and 3 km3 failure volume), have been suggested as possible failure occurrences in the published literature on a morphological basis and involve the north-eastern and north-western sectors of the volcano. The two additional cases, one medium-sized and one extreme, intended as a possible worst-case scenario (volume 17.6 km3), affecting the eastern flank. Results indicate that small-volume failures are not able to produce significant tsunamis; medium-size failures can produce tsunamis which dangerously affect the coasts if their detachment occurs in shallow water, i.e., involves the volcano crest; and extreme volume failures have the potential to create disastrous tsunamis. In all the simulations, tsunami waves appear to reach the Aeolian Islands in around 10 min and the coasts of Calabria and Sicily in 20 min. This study highlights that there is a potential for dangerous tsunamis generation from collapses of the Marsili volcano and as a consequence a need to intensify research on its status and stability conditions. More broadly, this investigation should also be extended to the other volcanic seamounts of the Tyrrhenian Sea, since their eruptive style, evolution, and tsunamigenic potential are still poorly known.

scholarly journals Ophelia roscoffensis Augener, 1910: a new polychaete record in Italian waters

Check List ◽  
2019 ◽  
Vol 15 (3) ◽  
pp. 489-495
Author(s):  
Emanuele Mancini ◽  
Francesco Tiralongo ◽  
Daniele Ventura ◽  
Andrea Bonifazi
Keyword(s):  
Mediterranean Sea ◽  
First Record ◽  
Posidonia Oceanica ◽  
Tyrrhenian Sea ◽  
The Mediterranean

Ophelia roscoffensis Augener, 1910 is an opheliid worm identifiable by the number of anterior abranchiate chaetigers and the number of the gill pairs. Although it was already reported in the Mediterranean Sea, it has never been found in the Italian waters. This study represents the first record of Ophelia roscoffensis in the Italian waters. A total of 18 specimens were collected along the coast of Civitavecchia (Tyrrhenian Sea) in a Posidonia oceanica (L.) Delile bed at a depth of 7 m.

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