scholarly journals Mapping global inputs and impacts from of human sewage in coastal ecosystems

PLoS ONE ◽  
2021 ◽  
Vol 16 (11) ◽  
pp. e0258898
Author(s):  
Cascade Tuholske ◽  
Benjamin S. Halpern ◽  
Gordon Blasco ◽  
Juan Carlos Villasenor ◽  
Melanie Frazier ◽  
...  

Coastal marine ecosystems face a host of pressures from both offshore and land-based human activity. Research on terrestrial threats to coastal ecosystems has primarily focused on agricultural runoff, specifically showcasing how fertilizers and livestock waste create coastal eutrophication, harmful algae blooms, or hypoxic or anoxic zones. These impacts not only harm coastal species and ecosystems but also impact human health and economic activities. Few studies have assessed impacts of human wastewater on coastal ecosystems and community health. As such, we lack a comprehensive, fine-resolution, global assessment of human sewage inputs that captures both pathogens and nutrient flows to coastal waters and the potential impacts on coastal ecosystems. To address this gap, we use a new high-resolution geospatial model to measure and map nitrogen (N) and pathogen—fecal indicator organisms (FIO)—inputs from human sewage for ~135,000 watersheds globally. Because solutions depend on the source, we separate nitrogen and pathogen inputs from sewer, septic, and direct inputs. Our model indicates that wastewater adds 6.2Tg nitrogen into coastal waters, which is approximately 40% of total nitrogen from agriculture. Of total wastewater N, 63% (3.9Tg N) comes from sewered systems, 5% (0.3Tg N) from septic, and 32% (2.0Tg N) from direct input. We find that just 25 watersheds contribute nearly half of all wastewater N, but wastewater impacts most coastlines globally, with sewered, septic, and untreated wastewater inputs varying greatly across watersheds and by country. Importantly, model results find that 58% of coral and 88% of seagrass beds are exposed to wastewater N input. Across watersheds, N and FIO inputs are generally correlated. However, our model identifies important fine-grained spatial heterogeneity that highlight potential tradeoffs and synergies essential for management actions. Reducing impacts of nitrogen and pathogens on coastal ecosystems requires a greater focus on where wastewater inputs vary across the planet. Researchers and practitioners can also overlay these global, high resolution, wastewater input maps with maps describing the distribution of habitats and species, including humans, to determine the where the impacts of wastewater pressures are highest. This will help prioritize conservation efforts.Without such information, coastal ecosystems and the human communities that depend on them will remain imperiled.

Author(s):  
Yakov Pachepsky ◽  
Matthew Stocker ◽  
Manuel Olmeda Saldaña ◽  
Daniel Shelton

1983 ◽  
Vol 29 (10) ◽  
pp. 1261-1269 ◽  
Author(s):  
W. J. Robertson ◽  
R. S. Tobin

Fifteen stations, in two estuaries, along the Northumberland Strait of Nova Scotia were examined between June and September 1981 for a relationship between the concentrations of commonly monitored fecal indicator bacteria and the potential pathogens Candida albicans, Pseudomonas aeruginosa, and Vibrio parahaemolyticus. Increased densities of these three organisms were usually associated with high densities of indicator bacteria. Whereas C. albicans and P. aeruginosa occur in human fecal wastes, V. parahaemolyticus is indigenous to the marine environment and positively responds to elevated nutrient levels in sewage. There is also some evidence that these bacteria survive as long or longer in marine waters than the common indicator bacteria. While membrane-filtration techniques for the enumeration of C. albicans and P. aeruginosa proved satisfactory, a V. parahaemolyticus membrane-filtration method lacked specificity and was supplemented by a most-probable-number method. In marine recreational and shellfish waters, these three organisms could complement fecal coliforms and fecal streptococci as indicators of human fecal contamination.


2021 ◽  
Vol 12 ◽  
Author(s):  
Jasmine H. Sharp ◽  
Katie Clements ◽  
Mallory Diggens ◽  
James E. McDonald ◽  
Shelagh K. Malham ◽  
...  

The fecal indicator organism (FIO) Escherichia coli is frequently used as a general indicator of sewage contamination and for evaluating the success of shellfish cleaning (depuration) processes. To evaluate the robustness of this approach, the accumulation, retention, and depuration of non-pathogenic E. coli, pathogenic E. coli O157:H7 and norovirus GII (NoV GII) RNA were evaluated using a combination of culture-based (E. coli) and molecular methods (E. coli, NoV GII) after exposure of mussels (Mytilus edulis) to water contaminated with human feces. We simulated water contamination after a point-source release from a combined sewer overflow (CSO) where untreated wastewater is released directly into the coastal zone. All three microbiological indicators accumulated rapidly in the mussels, reaching close to maximum concentration within 3 h of exposure, demonstrating that short CSO discharges pose an immediate threat to shellfish harvesting areas. Depuration (72 h) in clean water proved partially successful at removing both pathogenic and non-pathogenic E. coli from shellfish tissue, but failed to eradicate NoV GII RNA. We conclude that current EU standards for evaluating microbiological risk in shellfish are inadequate for protecting consumers against exposure to human norovirus GII found in polluted marine waters.


PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e10727
Author(s):  
Hiroki Murata ◽  
Motoyuki Hara ◽  
Chinatsu Yonezawa ◽  
Teruhisa Komatsu

Background Coastal ecosystems are blue infrastructures that support coastal resources and also aquaculture. Seagrass meadows, one of coastal ecosystems, provide substrates for epiphytic diatoms, which are food resources for cultured filter feeder organisms. Highly intensive coastal aquaculture degrades coastal environments to decrease seagrass meadows. Therefore, efficient aquaculture management and conservation of seagrass meadows are necessary for the sustainable development of coastal waters. In ria-type bays, non-feeding aquaculture of filter feeders such as oysters, scallops, and ascidians are actively practiced along the Sanriku Coast, Japan. Before the 2011 Great East Japan Earthquake, the over-deployment of oyster culture facilities polluted the bottom environment and formed an hypoxic bottom water layer due to the organic excrements from cultured oysters. The tsunami in 2011 devastated the aquaculture facilities and seagrass meadows along the Sanriku Coast. We mapped the oyster culture rafts and seagrass meadows in Nagatsura-ura Lagoon, Sanriku Coast before and after the tsunami and monitored those and environments after the tsunami by field surveys. Methods We conducted field surveys and monitored the environmental parameters in Nagatsura-ura Lagoon every month since 2014. We used high-resolution satellite remote sensing images to map oyster culture rafts and seagrass meadows at irregular time intervals from 2006 to 2019 in order to assess their distribution. In 2019, we also used an unmanned aerial vehicle to analyze the spatial variability of the position and the number of ropes suspending oyster clumps beneath the rafts. Results In 2013, the number and distribution of the oyster culture rafts had been completely restored to the pre-tsunami conditions. The mean area of culture raft increased after the tsunami, and ropes suspending oyster clumps attached to a raft in wider space. Experienced local fishermen also developed a method to attach less ropes to a raft, which was applied to half of the oyster culture rafts to improve oyster growth. The area of seagrass meadows has been expanding since 2013. Although the lagoon had experienced frequent oyster mass mortality events in summer before the tsunami, these events have not occurred since 2011. The 2011 earthquake and tsunami deepened the sill depth and widened the entrance to enhance water exchange and improve water quality in the lagoon. These changes brought the expansion of seagrass meadows and reduction of mass mortality events to allow sustainable oyster culture in the lagoon. Mapping and monitoring of seagrass meadows and aquaculture facilities via satellite remote sensing can provide clear visualization of their temporal changes. This can in turn facilitate effective aquaculture management and conservation of coastal ecosystems, which are crucial for the sustainable development of coastal waters.


2018 ◽  
Vol 82 (1) ◽  
pp. 55 ◽  
Author(s):  
Raouia Ghanem ◽  
Emna Soufi Kechaou ◽  
Jamila Ben Souissi ◽  
Joaquim Garrabou

Gorgonian species play an important ecological role in the structure and function of marine communities. Human activities are negatively affecting the conservation status of gorgonian populations in the Mediterranean. Acquiring knowledge of gorgonian distribution is therefore a key step required to promote efficient management and conservation actions. However, information on the distribution of gorgonian species is lacking in many Mediterranean areas. This study aimed to provide an overview of the geographic and bathymetric distributions of gorgonians in the coastal waters of the Tunisian coast (1136 km). The sampling design encompassed three sectors, 27 localities and 87 sites. Information was collected from scuba diving (26 sites) and local ecological knowledge surveys of fishermen and divers (132 interviews), as well as from a literature review. Overall, the occurrence of eight gorgonians was confirmed at 54 out of the 87 sites surveyed in Tunisian coastal waters (7-120 m depth). The species that were found were Eunicella singularis, Eunicella cavolini, Paramuricea clavata, Paramuricea macrospina, Leptogorgia sarmentosa, Eunicella verrucosa, Corallium rubrum and Ellisella paraplexauroides. The highest gorgonian species richness and abundance was recorded in northern, followed by eastern Tunisian waters. In the southern areas only one species was recorded. This pattern was related to the rocky substrate that characterizes the northern and eastern coasts of Tunisia. This study is the first to report the occurrence of E. singularis, E. cavolini, E. verrucosa and Leptogorgia sarmentosa in northern and eastern Tunisian waters. The results are discussed in the hope of guiding future conservation and management actions for gorgonian assemblages in Tunisia.


1983 ◽  
Vol 17 (4) ◽  
pp. 397-402 ◽  
Author(s):  
Badri Fattal ◽  
Robert J. Vasl ◽  
Eliyahu Katzenelson ◽  
Hillel I. Shuval

2009 ◽  
Vol 75 (21) ◽  
pp. 6736-6744 ◽  
Author(s):  
Karen St-Pierre ◽  
Simon Lévesque ◽  
Eric Frost ◽  
Nathalie Carrier ◽  
Robert D. Arbeit ◽  
...  

ABSTRACT This study aimed to assess the importance of quantitatively detecting Campylobacter spp. in environmental surface water. The prevalence and the quantity of Campylobacter spp., thermotolerant coliforms, and Escherichia coli in 2,471 samples collected weekly, over a 2-year period, from 13 rivers and 12 streams in the Eastern Townships, Québec, Canada, were determined. Overall, 1,071 (43%), 1,481 (60%), and 1,463 (59%) samples were positive for Campylobacter spp., thermotolerant coliforms, and E. coli, respectively. There were weak correlations between the weekly distributions of Campylobacter spp. and thermotolerant coliforms (Spearman's ρ coefficient = 0.27; P = 0.008) and between the quantitative levels of the two classes of organisms (Kendall tau-b correlation coefficient = 0.233; P < 0.0001). Well water samples from the Eastern Townships were also tested. Five (10%) of 53 samples from private surface wells were positive for Campylobacter jejuni, of which only 2 were positive for thermotolerant coliforms. These findings suggest that microbial monitoring of raw water by using only fecal indicator organisms is not sufficient for assessing the occurrence or the load of thermophilic Campylobacter spp. Insights into the role of environmental water as sources for sporadic Campylobacter infection will require genus-specific monitoring techniques.


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