scholarly journals Time Variability Patterns of Eutrophication Indicators in the Bay of Algeciras (South Spain)

Water ◽  
2018 ◽  
Vol 10 (7) ◽  
pp. 938
Author(s):  
Jesús Mercado ◽  
Pablo León ◽  
Soluna Salles ◽  
Dolores Cortés ◽  
Lidia Yebra ◽  
...  
Keyword(s):  
Chlorophyll A ◽  
Inorganic Nitrogen ◽  
Principal Component ◽  
Time Variability ◽  
Nutrient Loads ◽  
Vertical Variation ◽  
High Concentrations ◽  
Upwelling Intensity ◽  
Physical And Chemical ◽  
The Impact

In the Bay of Algeciras (BA), intensive urban and industrial activityis underway, which is potentially responsible for the release of significant quantities of nutrients. However, the assessment of the impact of these discharges is complex. Nutrient concentration in the surface layer is per se strongly variable due to the variability associated with the upwelling of nutrient-enriched deep Mediterranean water (MW), which in turn is regulated by atmospheric forcing. The aim of this study is to determine the effects of changes in the upwelling intensity on the load of nitrate and phosphate in the BA and to appraise their impact on chlorophyll a variability. Based on this analysis, the possible influence of the nutrients released from land-based sources is indirectly inferred. Data and samples collected during nine research cruises carried out in different seasonal cycle periods between 2010 and 2015 in the BA were analysed. The vertical variation of temperature and salinity indicates that the MW upwelling was favoured in spring, as occurred in other coastal areas of the northern Alboran Sea. However, principal component analysis conducted on physical and chemical data reveals that shifts in nutrients and chlorophyll a in the euphotic layer are poorly explained by changes in the upwelling intensity. Furthermore, during some of these research surveys (particularly in summer), chlorophyll a concentrations were higher in the BA as compared to a nearby coastal area also affected by MW upwelling. Scarce information about land-based pollution sources precludes quantitative analysis of the impact of nutrient loads on water quality; however, the available data suggest that the main source of allochthanous inorganic nitrogen over the period 2010–2015 in the BA was nitrate. Therefore, it is reasonable to hypothesize that the high concentrations of nitrate and chlorophyll a in BA in summer are a consequence of those discharges. Our study highlights the need of more exhaustive inventories of sewage and river discharges to adequately rate their impact in the BA.

scholarly journals Impact of maintenance of Macrobrachium rosenbergii De Man, 1879 (Crustacea, Decapoda, Palaemonidae) broodstock on the water used in culture ponds

2011 ◽  
Vol 71 (4) ◽  
pp. 857-863 ◽  
Author(s):  
JFV. Biudes ◽  
AFM. Camargo ◽  
MNP. Henares
Keyword(s):  
Chlorophyll A ◽  
Inorganic Nitrogen ◽  
Macrobrachium Rosenbergii ◽  
Economic Benefits ◽  
Effluent Water ◽  
Nitrogen And Phosphorus ◽  
Dissolved Phosphorus ◽  
Physical And Chemical ◽  
The Impact ◽  
Kjeldahl Nitrogen

Aquaculture production generates social and economic benefits, but can also cause environmental impacts. The objectives of this study were: a) to characterise the impacts caused by the maintenance of broodstock of the giant river prawn (Macrobrachium rosenbergii) on the physical and chemical characteristics of the water used in culture ponds, and b) to evaluate the relationship between the biomass of the prawns and the impact of culture on the water used in the ponds. Between January and December 2004, we determined, monthly, the biomass of M. rosenbergii by means of biometrics, and the physical and chemical variables of the supply and effluent water from a pond used to maintain breeding stock. The results showed that the effluent water had higher contents of chlorophyll-a, suspended particulate matter (SPM), pH, dissolved oxygen, total Kjeldahl nitrogen (TKN) and dissolved Kjeldahl nitrogen (DKN), inorganic nitrogen (IN), total (TP) and dissolved phosphorus (DP), and P-orthophosphate than the supply water. The highest biomass of M. rosenbergii occurred in April (127.0 g.m-2) and the lowest in August (71.5 g.m-2), and there were positive linear correlations between the biomass of the prawns and the intensity of the increases in TKN, DKN, IN, TP, and DP of the water used in the pond. The maintenance of broodstock of M. rosenbergii increased the chlorophyll-a, SPM, nitrogen, and phosphorus contents of the water in the pond. Additionally, the increase in the biomass of the prawns intensifies the export of nitrogen and phosphorus from the pond in the effluent.

scholarly journals Physical and Chemical Characteristics of a Mediterranean Coastal Microenvironment: The "Salty Lake" of Aghios Nikolaos (Crete, Greece)

2013 ◽  
Vol 2 (2) ◽  
pp. 167-178
Keyword(s):  
Coastal Waters ◽  
Marine Ecosystem ◽  
Anthropogenic Pollutants ◽  
High Concentrations ◽  
Lake Waters ◽  
Physical And Chemical ◽  
The Impact ◽  
Very High ◽  
Production Of Ammonia

The present paper examines a small and deep (53 m) salty lake, as well as the adjacent harbor of Aghios Nikolaos (Crete). The survey was carried out in 1996. Physicochemical parameters indicated that the main characteristics of the system are the inflow of karstic water from underwater springs inside the lake and the permanent anoxic conditions prevailing in its deeper part, below the thermocline. Nutrient concentrations are very high throughout the water column of the lake. Ammonia is the main source of nitrogen in the summer, particularly below the thermocline, whereas nitrates have high concentrations during spring and autumn. The high levels of these nutrients in the adjacent to the lake harbor and coastal waters indicate clearly the impact of the lake to the marine ecosystem. Anthropogenic pollutants, such as aromatic hydrocarbons, show high concentrations above thermocline, at 5-10 m depths during all samplings. However no particular point source was identified. The presence of hydrocarbons contributes to ineffective oxygenation of the lake waters and facilitates the development of anoxia and the production of ammonia. The PAH concentrations at the sampling stations outside the lake are typical of marine environments, with relatively small oil-derived inputs, indicating the complex role of the system as a source and/or as a trap of PAHs.

scholarly journals Limnology of shallow lakes of the semi-arid Central Pampa of Argentina

2019 ◽  
Vol 31 ◽  
Author(s):  
Santiago Andrés Echaniz ◽  
Alicia María Vignatti
Keyword(s):  
Chlorophyll A ◽  
Fish Fauna ◽  
Chemical Diversity ◽  
Nutrient Concentrations ◽  
Urban Sewage ◽  
Low Salinity ◽  
Low Concentrations ◽  
High Concentrations ◽  
Physical And Chemical

Abstract Aim The Central Pampa of Argentina has three recognized phytogeographic regions that arise due to the decrease in rainfall towards the west. The area has numerous lakes that are mainly temporary, with hydroperiods that relate to climatic cycles, although some of them have changed due to anthropogenic influence. Some of these lakes have been studied with special reference to zooplankton, but information on their physical and chemical aspects is scarce. Consequently, managing and evaluating the anthropogenic effects on these ecosystems is challenging. The objective of this study was to explore the limnological characteristics of lakes in different regions in the Central Pampa that experience different anthropic influences. Methods Ten lakes were sampled seasonally (January, April, July, and October) during 2007. In situ measurements included transparency, pH, temperature, and dissolved oxygen concentration, and 2-L water samples were collected to determine salinity, ion composition, suspended solids, nutrient concentration, and phytoplankton chlorophyll- a concentration. Results Salinity ranged from 0.32-136.72 g L-1, with Na+ being the dominant ion in nine lakes and Cl- and HCO3- predominating in the higher- and lower-salinity lakes respectively. Nutrient concentrations were high (total Kjeldahl nitrogen: 7.97-34.69 mg L-1; total phosphorous: 4.07-14.82 mg L-1), and all lakes were hypertrophic. We determined three lake classes: i) lakes transformed from low-salinity lakes into hypersaline ones through human inactivation of the fluvial system that fed it; ii) mesosaline temporary lakes lacking fish, with low concentrations of chlorophyll-a and influenced by agricultural activities, and iii) subsaline and hyposaline lakes, highly modified by urban sewage, converted in permanent lakes (which allowed fish fauna development) and with reduced water transparency (due to high concentrations of phytoplankton chlorophyll-a). Conclusions The chemical diversity of the studied lakes is low, and their predominance of Na+ and Cl- indicated that evaporation and crystallization control the water chemistry. Additionally, this study showed the consequences of the anthropic impact, which alter water chemical composition, trophic structure and, thus, the ecological characteristics of lakes.

Impact of agronomic management and intensive fertilization on the soils of Panao

2019 ◽  
Vol 1 (1) ◽  
pp. 7-17
Author(s):  
Liliana Vega-Jara ◽  
Keyword(s):  
Organic Matter ◽  
Chemical Properties ◽  
Principal Component ◽  
Traditional Agriculture ◽  
Physical And Chemical Properties ◽  
Agronomic Management ◽  
Sensitive Characteristics ◽  
Physical And Chemical ◽  
The Impact ◽  
And Chemical Properties

In order to evaluate the impact of long-term agronomic management and intensive fertilization on the soil properties of Pachitea, this study was carried out. Five lots were taken from the province of Pachitea, representative soils of the type of management carried out in this agricultural context. A virgin or pristine soil as absolute control (SV), a soil with less than 20 years of traditional agriculture (SAT1), a soil with intensive fertilization for more than 40 years (SFI), a soil with traditional agriculture between 20-40 years (SAT2), a soil with organic fertilization for more than 40 years (SAO) and a forest soil (SB). Soil samples were taken f rom each 20 cm deep lot and all their physical and chemical properties were analyzed. The results were analyzed in a principal component analysis (PCA), analysis of variance (ANOVA) and regression analysis. The results showed that the agricultural use of the changes changed all the physical and chemical properties of the soil over time. The most sensitive characteristics were pH and organic matter (OM). The changeable acidity (AC) was explained by the presence of Aluminum (Al) and very little by hydrogen (H), suggesting that the degradation of soils is quite strong in this context. Key words: Organic matter, Aluminum, pH https://doi.org/10.47840/ReInA20191

scholarly journals DINÁMICA OCÉANO-ATMÓSFERA Y SU INFLUENCIA EN LA BIOMASA FITOPLANCTÓNICA, EN LA ZONA COSTERA DEL DEPARTAMENTO DEL MAGDALENA, CARIBE COLOMBIANO

2016 ◽  
Vol 39 (2) ◽  
Author(s):  
Lorena Marcela García Hoyos ◽  
Andrés Franco Herrera ◽  
Jeimmy Samanta Ramírez Barón ◽  
Diego Alejandro López Cerón
Keyword(s):  
Chlorophyll A ◽  
Field Trips ◽  
Ekman Transport ◽  
Atmospheric Conditions ◽  
Average Wind Speed ◽  
Direction Parallel ◽  
Average Wind ◽  
Chemical Anomalies ◽  
Upwelling Intensity ◽  
Physical And Chemical

From February to June 2008 at inshore sites of the Magdalena region, specifically in Gaira and Granate inlets and Taganga Bay, six field trips were done comparing the main dry and short rainy seasons. The main aim was to determine the coupled ocean-atmosphere influence on the upwelling intensity, considering the physical and chemical variability within the water column between 0 and 60 m and the response of the phytoplankton community measured as chlorophyll a. Atmospheric, oceanographic, and biological conditions were evaluated following the Eulerian method. According to the oceanic and atmospheric conditions during the research period, Ekman transport and continental upwelling processes occurred through February and April, in response to adequate conditions: average wind speed (>4.0 m/s) and wind direction (parallel and perpendicular to the coast). Physical and chemical anomalies were detected in the water mass, such as low temperature (25.34±0.82°C), high salinity (35.5±0.30) and oxygen subsaturation (70.6±7.8 %). The inorganic nutrient supply was higher during upwelling processes,consequently, the system was defined as mesotrophic, causing greater phytoplankton chlorophyll a biomass with level up to 1.60 μg/L. "La Niña" 2007/2008 event, which covered the period of this of this research, did not incite any important disturbance over the typical upwelling conditions.

scholarly journals Classification of Clouds Sampled at the Puy de Dôme Station (France) Based on Chemical Measurements and Air Mass History Matrices

Atmosphere ◽  
2020 ◽  
Vol 11 (7) ◽  
pp. 732
Author(s):  
Pascal Renard ◽  
Angelica Bianco ◽  
Jean-Luc Baray ◽  
Maxime Bridoux ◽  
Anne-Marie Delort ◽  
...  
Keyword(s):  
Statistical Analysis ◽  
Principal Component ◽  
Cloud Microphysics ◽  
Back Trajectory ◽  
Air Mass ◽  
Air Masses ◽  
Chemical Measurements ◽  
History Of ◽  
High Concentrations ◽  
The Impact

A statistical analysis of 295 cloud samples collected at the Puy de Dôme station in France (PUY), covering the period 2001–2018, was conducted using principal component analysis (PCA), agglomerative hierarchical clustering (AHC), and partial least squares (PLS) regression. Our model classified the cloud water samples on the basis of their chemical concentrations and of the dynamical history of their air masses estimated with back-trajectory calculations. The statistical analysis split our dataset into two sets, i.e., the first set characterized by westerly air masses and marine characteristics, with high concentrations of sea salts and the second set having air masses originating from the northeastern sector and the “continental” zone, with high concentrations of potentially anthropogenic ions. It appears from our dataset that the influence of cloud microphysics remains minor at PUY as compared with the impact of the air mass history, i.e., physicochemical processes, such as multiphase reactivity.

scholarly journals Phytoplankton biomass dynamics and environmental variables around the Rocas Atoll Biological Reserve, South Atlantic

2015 ◽  
Vol 63 (4) ◽  
pp. 443-454 ◽  
Author(s):  
Marina Cavalcanti Jales ◽  
Fernando Antônio do Nascimento Feitosa ◽  
Maria Luise Koening ◽  
Manuel de Jesus Flores Montes ◽  
Moacyr Cunha de Araújo Filho ◽  
...  
Keyword(s):  
Chlorophyll A ◽  
Mixed Layer ◽  
Environmental Variables ◽  
Phytoplankton Biomass ◽  
Inorganic Nitrogen ◽  
Principal Component ◽  
Inorganic Phosphorus ◽  
Mean Value ◽  
South Atlantic ◽  
Biological Reserve

Abstract The Rocas Atoll Biological Reserve is located in the Atlantic Ocean, at 3º 51' S and 33º 49' W. It lies 143 nautical miles from the City of Natal, Rio Grande do Norte (Brazil). The purpose of this study was to analyze the hydrology, water masses, currents and chlorophyll a content to determine the dynamics of phytoplankton biomass around the Rocas Atoll. Samples were collected in July 2010 in the area around the Atoll, using the Research Vessel Cruzeiro do Sul of the Brazilian Navy. Two transects were established according to the surface currents, one of which at the southeast of the Atoll (SE) and the other at norwest (NW). Three collection points were determined on each of these transects. Samples were collected at different depths (surface and DCM - Deep Chlorophyll Maximum) and different times (day and night). According to PCA (Principal Component Analysis), the nutrients analyzed, DIN (dissolved inorganic nitrogen), DIP (dissolved inorganic phosphorus) and silicate, were inversely correlated with temperature and dissolved oxygen. Most environmental variables showed a significant increase due to the turbulence on the Northwest transect. There was an increase in the concentration of chlorophyll a and nutrients when the temperature and oxygen in the mixed layer was reduced due to the influence of the SACW (South Atlantic Central Water). Despite the increase observed in some variables such as nutrient salts and chlorophyll a, the temperature in the mixed layer attained a mean value of 23.23 ºC due to the predominance of Tropical Water. The increase of the phytoplankton biomass on the NW transect was, therefore, caused by the "island effect" and not by upwelling.

scholarly journals An improved approach for fault detection by simultaneous overcoming of high-dimensionality, autocorrelation, and time-variability

PLoS ONE ◽  
2020 ◽  
Vol 15 (12) ◽  
pp. e0243146
Author(s):  
Nastaran Hajarian ◽  
Farzad Movahedi Sobhani ◽  
Seyed Jafar Sadjadi
Keyword(s):  
Fault Detection ◽  
Control Charts ◽  
Principal Component ◽  
High Dimensionality ◽  
Time Variability ◽  
Process Data ◽  
Monitoring Method ◽  
Tennessee Eastman Process ◽  
Industrial Processing ◽  
The Impact

The control charts with the Principal Component Analysis (PCA) approach and its extension are among the data-driven methods for process monitoring and the detection of faults. Industrial processing data involves complexities such as high dimensionality, auto-correlation, and non-stationary which may occur simultaneously. An efficient fault detection technique is an approach that is robust against data training, sensitive to all the feasible faults of the process, and agile to the detection of the faults. To date, approaches such as the recursive PCA (RPCA) model and the moving-window PCA (MWPCA) model have been proposed when data is high-dimensional and non-stationary or dynamic PCA (DPCA) model and its extension have been suggested for autocorrelation data. But, using the techniques listed without considering all aspects of the process data increases fault detection indicators such as false alarm rate (FAR), delay time detection (DTD), and confuses the operator or causes adverse consequences. A new PCA monitoring method is proposed in this study, which can simultaneously reduce the impact of high-dimensionality, non-stationary, and autocorrelation properties. This technique utilizes DPCA property to decrease the effect of autocorrelation and adaptive behavior of MWPCA to control non-stationary characteristics. The proposed approach has been tested on the Tennessee Eastman Process (TEP). The findings suggest that the proposed approach is capable of detecting various forms of faults and comparing attempts to improve the detection of fault indicators with other approaches. The empirical application of the proposed approach has been implemented on a turbine exit temperature (TET). The results demonstrate that the proposed approach has detected a real fault successfully.

scholarly journals Assessing the impact of nutrient loads on eutrophication in the semi-enclosed Izmir Bay combining observations and coupled hydrodynamic-ecosystem modelling

2021 ◽  
Author(s):  
OZGE YELEKCI ◽  
VALERIA IBELLO ◽  
BETTINA A. FACH ◽  
FILIZ KUCUKSEZGIN ◽  
CAGLAR YUMRUKTEPE ◽  
...  
Keyword(s):  
Inorganic Nitrogen ◽  
Marine Ecosystem ◽  
Waste Water Treatment ◽  
Treatment Plant ◽  
Waste Water Treatment Plant ◽  
Spatial And Temporal Variability ◽  
Nutrient Loads ◽  
Algal Production ◽  
Izmir Bay ◽  
The Impact

Intense human activities may strongly affect coastal environments threatening natural, societal and economic resources. In order to propose adequate measures to preserve coastal marine areas, a thorough understanding of their physical and biogeochemical features is required. This study focuses on one such coastal area, Izmir Bay located in the Eastern Mediterranean Sea. Izmir Bay is a highly populated area subject to many human induced stressors such as pollution and eutrophication, that has been suffering high nutrient loads for decades. Despite the construction of the Çiğli waste water treatment plant in 2000-2001 to reduce eutrophication, such pressures continue to occur. To study the current physical and biogeochemical dynamics of Izmir Bay and their spatial and temporal variability, a three-dimensional coupled hydrodynamic-ecosystem model (Delft3D modelling suite’s FLOW and ECO modules) is implemented. Using the model, the effect of excessive inorganic nutrient loading on the marine ecosystem as the main cause of this eutrophication is explored in an effort to advise on mitigation efforts for the Bay focusing on eliminating eutrophication. Results of different model scenarios show that the Inner and Middle Bay are nitrogen-limited while the Outer Bay is phosphorus-limited. Inner regions are more sensitive to variations in inorganic nitrogen input due to the low (<16) N/P ratio of nutrients in seawater. An increase in inorganic nitrogen triggers eutrophication events with primary production as an immediate response. Conversely, the Outer Bay ecosystem with N/P ratios above 16 is more sensitive to phosphate inputs, of which an increase causes a considerable enhancement in algal production. This study shows the vulnerability of Izmir Bay to anthropogenic nutrient input and model simulations indicate that management plans should consider reducing DIN discharges both in the inner-middle zones of Izmir Bay as well as inputs from the Gediz River. Additionally, phosphate inputs should be reduced to avoid an overall increase of algal production in the Outer Bay, the larger part of Izmir Bay.

An assessment of water quality in a coastal embayment (Phaleron Bay, Greece)

1995 ◽  
Vol 32 (7) ◽  
pp. 25-32 ◽  
Author(s):  
A. J. Theodorou
Keyword(s):  
Water Quality ◽  
Environmental Management ◽  
Water Column ◽  
Chlorophyll A ◽  
River Discharge ◽  
Benthic Communities ◽  
Coastal Embayment ◽  
Oceanographic Data ◽  
High Concentrations ◽  
The Impact

Athens basin drains by gravity to the coast into the Phaleron Bay by the Kifissos river. The Phaleron coast is currently undergoing extensive remodelling and is scheduled for development as a major amenity and recreational centre. Thus, an assessment of the Phaleron Bay's present water quality constitutes a prerequisite for the future environmental management of its waters. Analysis of oceanographic data, collected during 1989–1990, showed that eutrophic conditions prevail in the vicinity of Kifissos river, where nutrients and chlorophyll-a occur in high concentrations. Also in this area, the benthic communities have been modified and they are dominated by detritus or sediment feeding polychaetes. However, beyond this region the impact of the river discharge diminishes with distance offshore and in the entrance of the bay, both water column quality and benthos are indistinguishable from those of the open Saronikos Gulf.

Sign in / Sign up

Export Citation Format

Share Document