scholarly journals Influence of the Intrinsic Characteristics of Cementitious Materials on Biofouling in the Marine Environment

2021 ◽  
Vol 13 (5) ◽  
pp. 2625
Author(s):  
Mahmoud Hayek ◽  
Marie Salgues ◽  
Jean-Claude Souche ◽  
Etienne Cunge ◽  
Cyril Giraudel ◽  
...  

Coastal marine ecosystems provide essential benefits and services to humanity, but many are rapidly degrading. Human activities are leading to significant land take along coastlines and to major changes in ecosystems. Ecological engineering tools capable of promoting large-scale restoration of coastal ecosystems are needed today in the face of intensifying climatic stress and human activities. Concrete is one of the materials most commonly used in the construction of coastal and marine infrastructure. Immersed in seawater, concretes are rapidly colonized by microorganisms and macroorganisms. Surface colonization and subsequent biofilm and biofouling formation provide numerous advantages to these organisms and support critical ecological and biogeochemical functions in the changing marine environment. The new challenge of the 21st century is to develop innovative concretes that, in addition to their usual properties, provide improved bioreceptivity in order to enhance marine biodiversity. The aim of this study is to master and clarify the intrinsic parameters that influence the bioreceptivity (biocolonization) of cementitious materials in the marine environment. By coupling biofilm (culture-based methods) and biofouling (image-analysis-based method and wet-/dry-weight biomass measurement) quantification techniques, this study showed that the application of a curing compound to the concrete surface reduced the biocolonization of cementitious materials in seawater, whereas green formwork oil had the opposite effect. This study also found that certain surface conditions (faceted and patterned surface, rough surface) promote the bacterial and macroorganism colonization of cementitious materials. Among the parameters examined, surface roughness proved to be the factor that promotes biocolonization most effectively. These results could be taken up in future recommendations to enable engineers to eco-design more eco-friendly marine infrastructure and develop green-engineering projects.

2017 ◽  
Vol 74 (7) ◽  
pp. 1009-1015 ◽  
Author(s):  
Zofia Baumann ◽  
Robert P. Mason ◽  
David O. Conover ◽  
Prentiss Balcom ◽  
Celia Y. Chen ◽  
...  

Human exposure to the neurotoxic methylmercury (MeHg) occurs primarily via the consumption of marine fish, but the processes underlying large-scale spatial variations in fish MeHg concentrations [MeHg], which influence human exposure, are not sufficiently understood. We used the Atlantic silverside (Menidia menidia), an extensively studied model species and important forage fish, to examine latitudinal patterns in total mercury (Hg) [Hg] and [MeHg]. Both [Hg] and [MeHg] significantly increased with latitude (0.014 and 0.048 μg MeHg·g dry weight−1 per degree of latitude in juveniles and adults, respectively). Four known latitudinal trends in silverside traits help explain these patterns: latitudinal increase in MeHg assimilation efficiency, latitudinal decrease in MeHg efflux, latitudinal increase in weight loss due to longer and more severe winters, and latitudinal increase in food consumption as an adaptation to decreasing length of the growing season. Given the absence of a latitudinal pattern in particulate MeHg, a diet proxy for zooplanktivorous fish, we conclude that large-scale spatial variation in growth is the primary control of Hg bioaccumulation in this and potentially other fish species.


2019 ◽  
Vol 11 (16) ◽  
pp. 4450
Author(s):  
Vanessa Hull ◽  
Christian J. Rivera ◽  
Chad Wong

The world’s oceans face unprecedented anthropogenic threats in the globalized era that originate from all over the world, including climate change, global trade and transportation, and pollution. Marine protected areas (MPAs) serve important roles in conservation of marine biodiversity and ecosystem resilience, but their success is increasingly challenged in the face of such large-scale threats. Here, we illustrate the utility of adopting the interdisciplinary telecoupling framework to better understand effects that originate from distant places and cross MPA boundaries (e.g., polluted water circulation, anthropogenic noise transport, human and animal migration). We review evidence of distal processes affecting MPAs and the cutting-edge approaches currently used to investigate these processes. We then introduce the umbrella framework of telecoupling and explain how it can help address knowledge gaps that exist due to limitations of past approaches that are centered within individual disciplines. We then synthesize five examples from the recent telecoupling literature to explore how the telecoupling framework can be used for MPA research. These examples include the spatial subsidies approach, adapted social network analysis, telecoupled qualitative analysis, telecoupled supply chain analysis, and decision support tools for telecoupling. Our work highlights the potential for the telecoupling framework to better understand and address the mounting and interconnected socioeconomic and environmental sustainability challenges faced by the growing number of MPAs around the world.


Author(s):  
Herman Hummel ◽  
Pim Van Avesaath ◽  
Sander Wijnhoven ◽  
Loran Kleine-Schaars ◽  
Steven Degraer ◽  
...  

Within the COST action EMBOS (European Marine Biodiversity Observatory System) the degree and variation of the diversity and densities of soft-bottom communities from the lower intertidal or the shallow subtidal was measured at 28 marine sites along the European coastline (Baltic, Atlantic, Mediterranean) using jointly agreed and harmonized protocols, tools and indicators. The hypothesis tested was that the diversity for all taxonomic groups would decrease with increasing latitude. The EMBOS system delivered accurate and comparable data on the diversity and densities of the soft sediment macrozoobenthic community over a large-scale gradient along the European coastline. In contrast to general biogeographic theory, species diversity showed no linear relationship with latitude, yet a bell-shaped relation was found. The diversity and densities of benthos were mostly positively correlated with environmental factors such as temperature, salinity, mud and organic matter content in sediment, or wave height, and related with location characteristics such as system type (lagoons, estuaries, open coast) or stratum (intertidal, subtidal). For some relationships, a maximum (e.g. temperature from 15–20°C; mud content of sediment around 40%) or bimodal curve (e.g. salinity) was found. In lagoons the densities were twice higher than in other locations, and at open coasts the diversity was much lower than in other locations. We conclude that latitudinal trends and regional differences in diversity and densities are strongly influenced by, i.e. merely the result of, particular sets and ranges of environmental factors and location characteristics specific to certain areas, such as the Baltic, with typical salinity clines (favouring insects) and the Mediterranean, with higher temperatures (favouring crustaceans). Therefore, eventual trends with latitude are primarily indirect and so can be overcome by local variation of environmental factors.


ZooKeys ◽  
2018 ◽  
Vol 787 ◽  
pp. 135-149 ◽  
Author(s):  
Sally Rouse ◽  
Jennifer Loxton ◽  
Mary E. Spencer Jones ◽  
Joanne S. Porter

Contemporary and historical bryozoan records were compiled to provide a comprehensive checklist of species in Scottish waters. The checklist comprises 218 species in 58 families, with representatives from each of the extant bryozoan orders. The fauna was relatively sparse compared to other regions for which bryozoan checklists were available e.g. New Zealand and Australia. Six non-indigenous bryozoan species from the Scottish seas region were included in the checklist. Baseline information on species distributions, such as that presented in this checklist, can be used to monitor and manage the impact of human activities on the marine environment, and ultimately preserve marine biodiversity.


2021 ◽  
Vol 8 ◽  
Author(s):  
Frances Mynott ◽  
Jemma-Anne Lonsdale ◽  
Tammy Stamford

Maritime states are faced with the challenge of effectively managing their marine spaces to use resources sustainably, maximise economic potential and simultaneously protect their marine environments. Anthropogenic activities, whether in isolation or combination, all have effects on the natural environment. Each of these effects has a footprint in time and space. Assessing the distribution and intensity of human activities and their effects on marine biodiversity, and all other human uses and users is necessary for effective spatial planning, as well as to harmonise conservation with sustainable development. Assessing and managing combined pressures from human activities can be achieved using risk assessment and risk management processes. There are multiple examples of environmental risk assessments which propose a similar formula. However, standardised approaches to ecological risk assessment in data-limited locations that relate to sand extraction are limited. Also most assessments require a certain level of information to produce meaningful outcomes, that enable subsequent management action to appropriately reflect the identified level of risk. Here we outline an approach to assess the risk to the marine environment of sand extraction activity within the Exclusive Economic Zone and Marine Protected Area of St Helena Island in the Atlantic. The proposed risk assessment tool has supported the development of a sand extraction management strategy on St Helena, and will be used to inform future management plans and policies that allow anthropogenic activities to take place in a way that balances local management, monitoring and enforcement capability, in line with the International Union for Conservation of Nature (IUCN) Category VI designation. Both the tool and strategy promote sustainable use of resources and protection of the marine environment, which are key objectives stated in the St Helena Marine Management Plan.


2021 ◽  
Vol 9 ◽  
Author(s):  
David R. Schiel ◽  
Shawn Gerrity ◽  
Shane Orchard ◽  
Tommaso Alestra ◽  
Robyn A. Dunmore ◽  
...  

Understanding the resilience and recovery processes of coastal marine ecosystems is of increasing importance in the face of increasing disturbances and stressors. Large-scale, catastrophic events can re-set the structure and functioning of ecosystems, and potentially lead to different stable states. Such an event occurred in south-eastern New Zealand when a Mw 7.8 earthquake lifted the coastline by up to 6 m. This caused widespread mortality of intertidal algal and invertebrate communities over 130 km of coast. This study involved structured and detailed sampling of three intertidal zones at 16 sites nested into four degree of uplift (none, 0.4–1, 1.5–2.5, and 4.5–6 m). Recovery of large brown algal assemblages, the canopy species of which were almost entirely fucoids, were devastated by the uplift, and recovery after 4 years was generally poor except at sites with < 1 m of uplift. The physical infrastructural changes to reefs were severe, with intertidal emersion temperatures frequently above 35°C and up to 50°C, which was lethal to remnant populations and recruiting algae. Erosion of the reefs composed of soft sedimentary rocks was severe. Shifting sand and gravel covered some lower reef areas during storms, and the nearshore light environment was frequently below compensation points for algal production, especially for the largest fucoid Durvillaea antarctica/poha. Low uplift sites recovered much of their pre-earthquake assemblages, but only in the low tidal zone. The mid and high tidal zones of all uplifted sites remained depauperate. Fucoids recruited well in the low zone of low uplift sites but then were affected by a severe heat wave a year after the earthquake that reduced their cover. This was followed by a great increase in fleshy red algae, which then precluded recruitment of large brown algae. The interactions of species’ life histories and the altered physical and ecological infrastructure on which they rely are instructive for attempts to lessen manageable stressors in coastal environments and help future-proof against the effects of compounded impacts.


1995 ◽  
Vol 32 (9-10) ◽  
pp. 85-94 ◽  
Author(s):  
Michael O. Angelidis

The impact of the urban effluents of Mytilene (Lesvos island, Greece) on the receiving coastal marine environment, was evaluated by studying the quality of the city effluents (BOD5, COD, SS, heavy metals) and the marine sediments (grain size, organic matter, heavy metals). It was found that the urban effluents of Mytilene contain high organic matter and suspended particle load because of septage discharge into the sewerage network. Furthermore, although the city does not host important industrial activity, its effluents contain appreciable metal load, which is mainly associated with the particulate phase. The city effluents are discharged into the coastal marine environment and their colloidal and particulate matter after flocculation settles to the bottom, where is incorporated into the sediments. Over the years, the accumulation of organic matter and metals into the harbour mud has created a non-point pollution source in the relatively non-polluted coastal marine environment of the island. Copper and Zn were the metals which presented the higher enrichment in the sediments of the inner harbour of Mytilene.


2020 ◽  
Vol 17 (4) ◽  
pp. 507-514 ◽  
Author(s):  
Krishnamoorthy Venkateskumar ◽  
Subramani Parasuraman ◽  
Leow Y. Chuen ◽  
Veerasamy Ravichandran ◽  
Subramani Balamurgan

About 95% of earth living space lies deep below the ocean’s surface and it harbors extraordinary diversity of marine organisms. Marine biodiversity is an exceptional reservoir of natural products, bioactive compounds, nutraceuticals and other potential compounds of commercial value. Timeline for the development of the drug from a plant, synthetic and other alternative sources is too lengthy. Exploration of the marine environment for potential bioactive compounds has gained focus and huge opportunity lies ahead for the exploration of such vast resources in the ocean. Further, the evolution of superbugs with increasing resistance to the currently available drugs is alarming and it needs coordinated efforts to resolve them. World Health Organization recommends the need and necessity to develop effective bioactive compounds to combat problems associated with antimicrobial resistance. Based on these factors, it is imperative to shift the focus towards the marine environment for potential bioactive compounds that could be utilized to tackle antimicrobial resistance. Current research trends also indicate the huge strides in research involving marine environment for drug discovery. The objective of this review article is to provide an overview of marine resources, recently reported research from marine resources, challenges, future research prospects in the marine environment.


Author(s):  
Richard Gowan

During Ban Ki-moon’s tenure, the Security Council was shaken by P5 divisions over Kosovo, Georgia, Libya, Syria, and Ukraine. Yet it also continued to mandate and sustain large-scale peacekeeping operations in Africa, placing major burdens on the UN Secretariat. The chapter will argue that Ban initially took a cautious approach to controversies with the Council, and earned a reputation for excessive passivity in the face of crisis and deference to the United States. The second half of the chapter suggests that Ban shifted to a more activist pressure as his tenure went on, pressing the Council to act in cases including Côte d’Ivoire, Libya, and Syria. The chapter will argue that Ban had only a marginal impact on Council decision-making, even though he made a creditable effort to speak truth to power over cases such as the Central African Republic (CAR), challenging Council members to live up to their responsibilities.


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