scholarly journals Marine Heatwaves, Sewage and Eutrophication Combine to Trigger Deoxygenation and Biodiversity Loss: A SW Atlantic Case Study

2020 ◽  
Vol 7 ◽  
Author(s):  
Kalina M. Brauko ◽  
Alex Cabral ◽  
Natasha V. Costa ◽  
Juliana Hayden ◽  
Carlos E. P. Dias ◽  
...  

Marine heatwaves (MHWs) are a major concern worldwide due to their increasing impacts in recent years, and these extreme events may trigger deoxygenation of coastal waters affected by sewage and eutrophication. Here we investigate the combined effects of MHWs and nutrient enrichment on the water quality and biodiversity of the Bay of Santa Catarina Island (Brazil). We used historical (1994–2020) sea surface temperature data from satellites and in situ physical, chemical and biological parameters to assess temporal trends. Oxygen levels have been decreasing whilst phosphorus levels have been increasing in the bay. During the austral summer of 2020 a regional sea surface heatwave was detected by satellite, lasting for 9 days and coinciding with our research cruise. During this period, seawater temperatures reached 29.8°C and anoxia was detected for the first time in the bay. A decrease in macrobenthic and phytoplankton community richness correlated with decreases in oxygen both through time and towards more urbanized areas. Overall, poor wastewater treatment is a key stressor that combined with MHWs to degrade coastal waters. Mitigation strategies are needed to minimize the impact of MHWs, including improved sewage treatment, restoration and conservation of wetlands and the use of nature-based technologies to promote coastal ecosystem recovery.

1986 ◽  
Vol 18 (9) ◽  
pp. 57-68 ◽  
Author(s):  
R. Olivotti ◽  
J. Faganeli ◽  
A. Malej

The main sources of potential ‘organic' pollutants (essentially pathogens, nutrients, floatables, suspended solids and detergents) discharged to the Gulf of Trieste by sewers and rivers are briefly reviewed; about 470,000 people live in the coastal area, and nearly 400,000 of them discharge sewage effluents to the Gulf. This brief review is followed by an evaluation of the impact of such discharges on the quality of marine waters, with reference to the impairment of uses such as bathing and shellfish cultivation. The sanitary and aesthetic aspects of faecal pollution which typically affect coastal waters are examined together with the water quality standards pertaining to bathing waters and shellfish cultivation areas; the extent of pollution of the coastal waters is determined. Experience gained at some wastewater treatment and disposal works is cited. On the whole, the Gulf of Trieste appears to be in a satisfactory condition: more than 85% of the shoreline (totalling 42 km in Yugoslavia and 93 km in Italy) is unpolluted, according to the pertaining standards. Ameliorations are, however, urgently needed in many respects. Recommendations regarding adequate forms of sewage treatment and disposal are made.


2015 ◽  
Vol 12 (2) ◽  
pp. 245 ◽  
Author(s):  
Andrea Bazzano ◽  
Francesco Soggia ◽  
Marco Grotti

Environmental context The atmosphere above Antarctica, the cleanest part of the Earth’s troposphere, serves as a valuable laboratory for studying natural atmospheric processes and for monitoring the impact of human activities on the global environment. Central to these studies is an understanding of long-range transport of pollutants to Antarctica, and distinguishing the relative contribution of natural and anthropogenic sources. We use chemical tracers and isotopic analysis to assess the origin of metals associated with atmospheric particulates in Antarctica. Abstract During the 2010–2011 austral summer, size-segregated aerosol samples were collected at a coastal Antarctic site (Terra Nova Bay, Victoria Land) and analysed for major and trace elements and lead isotopic composition, in order to provide a better understanding of the sources of metals and their transportation pathways towards Antarctica. Aerosol size fractionation was performed by a cascade impactor, able to collect aerosol particles of aerodynamic diameter 10–7.2, 7.2–3.0, 3.0–1.5, 1.5–0.95 and 0.95–0.49µm. It was found that Al, Co, Fe, Li, Mn, Rb, Y and V were mainly related to crustal inputs, whereas the marine contribution was significant for Li, Mg, Na and Rb. An additional anthropogenic source influencing the concentration of Cr, Cu, Mo and Pb was clearly demonstrated. The concentration of the elements associated to the crustal and marine inputs showed high values in the coarse mode (7.2–3.0µm), whereas the anthropogenic elements were also characterised by a high concentration in the finer (1.5–0.95µm) particles. The study of the temporal trends of the measured chemical markers along with the meteorological variables revealed that both the crustal and anthropogenic elements were related to the air masses carried by the katabatic wind from the inland, whereas the marine input appeared to be higher in January when the sea-ice extent was reduced. Finally, lead isotope ratios pointed out that the anthropogenic input was likely related to the polluted aerosols from South America and Australia, representing the predominant fraction (50–70%) of the lead measured in the samples.


2021 ◽  
Vol 8 ◽  
Author(s):  
Camila Gallardo ◽  
Nicolas C. Ory ◽  
María de los Ángeles Gallardo ◽  
Marcel Ramos ◽  
Luis Bravo ◽  
...  

The abundance and distribution of plastic debris at the sea surface shows considerable variability over different spatial scales. Some of the oceanographic processes at small (<1 km) and submeso (1–10 km) scales manifest themselves as slicks at the sea surface, which might have the potential to concentrate organisms and particles (such as positively buoyant plastics), putting species that feed in these areas at risk of ingesting plastics. Slicks can be filaments, lines, meanders, or patches, which are lighter in color and smoother in surface roughness compared to the surrounding area. Here we tested the hypothesis that passive particles (including plastics) and organisms are aggregated in the surface waters within these slicks. According to their main features (orientation to coast and/or wind), the studied slicks were most likely generated by oceanographic processes such as topographically controlled fronts, other types of fronts and internal waves. Neuston samples were collected from the sea surface inside and outside of slicks (n = 11 sites with slicks) in the coastal waters of Rapa Nui (Easter Island) during two campaigns in austral summer (January 2018) and autumn (April 2019). In general, passive particles, including plastics, exuviae, eggs and foraminiferans, were found more frequently inside than outside the slicks. In some cases, motile zooplankton organisms such as chaetognaths, vertically migrating crustaceans and early developmental stages (EDS) of fish were also more common within the slicks. In addition, a positive relationship was found between plastics and planktonic organisms such as foraminiferans, snails and jellyfish (e.g., Velella velella), although a strong correlation was also found with fish EDS and chaetognaths. These results suggest that surface slicks are areas of aggregation for both passive particles and active organisms, thus playing an important ecological role in food retention and particle concentration where the risk of plastic ingestion by fish and seabirds is enhanced.


1986 ◽  
Vol 18 (9) ◽  
pp. 77-84
Author(s):  
M. I. Mastrović ◽  
G. D. Šilović

This paper emphasizes the need for detailed analysis of wastewaters and their impact on the environment in physical plans for urban/tourist coastal areas, as a significant contribution to environmentally sound development, especially the development of tourism in these areas. The paper describes an analysis of this kind, prepared as part of the Regional Physical Plan for the Rijeka Region to the Year 2000. (The Rijeka Region is a major part of the Yugoslav Upper Adriatic.) The existing situation regarding sewerage systems, sewage treatment methods and disposal methods of the communes of the Region is presented. The quantities of wastewaters generated by the residential and tourist populations and by industry are given (by sub-regions) as calculated in 1981 and as estimated for the year 2000. A survey was made of the impact of wastewater on receiving rivers and coastal waters, and the quality of the receiving waters is given, in grades as compared with those prescribed by the Yugoslav legal regulations. Based on urban development concepts, and on the estimated wastewater quantities, alternative forecasts are made of the future impact of wastewater on coastal waters. General guidelines are presented for the provision of adequate sewage disposal facilities in order to achieve the optimum situation.


Atmosphere ◽  
2020 ◽  
Vol 11 (6) ◽  
pp. 585 ◽  
Author(s):  
Abhirup Dikshit ◽  
Biswajeet Pradhan ◽  
Abdullah M. Alamri

Droughts can cause significant damage to agriculture and water resources leading to severe economic losses. One of the most important aspects of drought management is to develop useful tools to forecast drought events, which could be helpful in mitigation strategies. The recent global trends in drought events reveal that climate change would be a dominant factor in influencing such events. The present study aims to understand this effect for the New South Wales (NSW) region of Australia, which has suffered from several droughts in recent decades. The understanding of the drought is usually carried out using a drought index, therefore the Standard Precipitation Evaporation Index (SPEI) was chosen as it uses both rainfall and temperature parameters in its calculation and has proven to better reflect drought. The drought index was calculated at various time scales (1, 3, 6, and 12 months) using a Climate Research Unit (CRU) dataset. The study focused on predicting the temporal aspect of the drought index using 13 different variables, of which eight were climatic drivers and sea surface temperature indices, and the remainder were various meteorological variables. The models used for forecasting were an artificial neural network (ANN) and support vector regression (SVR). The model was trained from 1901–2010 and tested for nine years (2011–2018), using three different performance metric scores (coefficient of determination (R2), root mean square error (RMSE), and mean absolute error (MAE). The results indicate that ANN was better than SVR in predicting temporal drought trends, with the highest R2 value of 0.86 for the former compared to 0.75 for the latter. The study also reveals that sea surface temperatures and the climatic index (Pacific Decadal Oscillation) do not have a significant effect on the temporal drought aspect. The present work can be considered as a first step, wherein we only study the temporal trends, towards the use of climatological variables and drought incidences for the NSW region.


2020 ◽  
Vol 42 (1) ◽  
pp. 67-74
Author(s):  
Vu Van Tac

This paper focuses on analyzing the monthly averaged sea surface chlorophyll_a concentration data for 16 years (Jul. 2002 ÷ Sep. 2018), a remote sensing data product of the US National Aeronautics and Space Administration (US NASA), the analyzed results have shown that each occurrence of ENSO phenomenon greatly affects the fluctuation of chlorophyll_a concentration in the South Vietnam‘s coastal waters (SVNC). The monthly averaged chlorophyll_a concentration varies from 0.5 [mg/m3] to 1.1 [mg/m3] (equivalent to 22.4% ÷ 49.3%), while the monthly averaged fluctuation of chlorophyll_a concentration between months is only 0.22 [mg/m3] (equivalent to 9.88%). These fluctuations have a great impact on nutritional resources as well as water quality because chlorophyll_a is a pigment in plankton, which is a criterion to assess the "rich or poor" of nutrition source in seawater. The results of this study are considered as a "small piece" in the overall picture of the impact of ENSO phenomenon on global climate change.


Author(s):  
Vu Van Tac ◽  
Nguyen Huu Huan ◽  
Tong Phuoc Hoang Son ◽  
Manh Manh Tien ◽  
Nguyen Hoang Thai Khang ◽  
...  

The studies on the impact of the ENSO phenomenon on climate and environment change have shown that the Bien Dong (Southeast Asia Sea) is strongly influenced by this phenomenon. This paper focuses on analyzing sea surface temperature (SST) monthly data for 16 years (7/2002–12/2017) in the coastal waters of Vietnam from MODIS satellite images of National Aeronautics and Space Administration (US NASA). The analysis results showed a clear pattern of ENSO impacts on SST in the coastal waters of Vietnam. However, the intensity of the ENSO phenomenon affecting the three studied areas is very different, and in terms of trend, the intensity gradually increases to the north. The period of impact of ENSO on SST in the coastal waters of Vietnam is often about one month later than the ONI index and the influenced duration lasts about 6 to 9 months. In addition, in the La Niña years, the values of the SST anomaly reflect quite well in terms of the intensity of the La Niña phenomenon. However, in the El Niño years, the SST anomaly index is not generally proportional to the ONI index. Specifically, in the years when El Niño phenomenon was considered to be weak, the SST anomaly index of the coastal waters of Vietnam is much higher than in the years when El Niño phenomenon was considered to be moderate or very strong. The above results are contributing to improving the understanding of the impact of the vagaries of the climate on the coastal waters of Vietnam, supporting scientists and managers in making measures to prevent and efficiently avoid, limit and mitigate the damage caused by ENSO, and to have reasonable alternatives in the protection of biodiversity and environment in the coastal waters of Vietnam. It could be considered as a “small piece” of the overall picture of the impacts of the ENSO phenomenon on global climate change.


Author(s):  
Sergei Soldatenko ◽  
Sergei Soldatenko ◽  
Genrikh Alekseev ◽  
Genrikh Alekseev ◽  
Alexander Danilov ◽  
...  

Every aspect of human operations faces a wide range of risks, some of which can cause serious consequences. By the start of 21st century, mankind has recognized a new class of risks posed by climate change. It is obvious, that the global climate is changing, and will continue to change, in ways that affect the planning and day to day operations of businesses, government agencies and other organizations and institutions. The manifestations of climate change include but not limited to rising sea levels, increasing temperature, flooding, melting polar sea ice, adverse weather events (e.g. heatwaves, drought, and storms) and a rise in related problems (e.g. health and environmental). Assessing and managing climate risks represent one of the most challenging issues of today and for the future. The purpose of the risk modeling system discussed in this paper is to provide a framework and methodology to quantify risks caused by climate change, to facilitate estimates of the impact of climate change on various spheres of human activities and to compare eventual adaptation and risk mitigation strategies. The system integrates both physical climate system and economic models together with knowledge-based subsystem, which can help support proactive risk management. System structure and its main components are considered. Special attention is paid to climate risk assessment, management and hedging in the Arctic coastal areas.


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