scholarly journals Modified Local Soil (MLS) Technology for Harmful Algal Bloom Control, Sediment Remediation, and Ecological Restoration

Water ◽  
2019 ◽  
Vol 11 (6) ◽  
pp. 1123 ◽  
Author(s):  
Gang Pan ◽  
Xiaojun Miao ◽  
Lei Bi ◽  
Honggang Zhang ◽  
Lei Wang ◽  
...  

Harmful algal blooms (HABs), eutrophication, and internal pollutant sources from sediment, represent serious problems for public health, water quality, and ecological restoration worldwide. Previous studies have indicated that Modified Local Soil (MLS) technology is an efficient and cost-effective method to flocculate the HABs from water and settle them onto sediment. Additionally, MLS capping treatment can reduce the resuspension of algae flocs from the sediment, and convert the algal cells, along with any excessive nutrients in-situ into fertilisers for the restoration of submerged macrophytes in shallow water systems. Furthermore, the capping treatment using oxygen nanobubble-MLS materials can also mitigate sediment anoxia, causing a reduction in the release of internal pollutants, such as nutrients and greenhouse gases. This paper reviews and quantifies the main features of MLS by investigating the effect of MLS treatment in five pilot-scale whole-pond field experiments carried out in Lake Tai, South China, and in Cetian Reservoir in Datong city, North China. Data obtained from field monitoring showed that the algae-dominated waters transform into a macrophyte-dominated state within four months of MLS treatment in shallow water systems. The sediment-water nutrient fluxes were substantially reduced, whilst water quality (TN, TP, and transparency) and biodiversity were significantly improved in the treatment ponds, compared to the control ponds within a duration ranging from one day to three years. The sediment anoxia remediation effect by oxygen nanobubble-MLS treatment may further contribute to deep water hypoxia remediation and eutrophication control. Combined with the integrated management of external loads control, MLS technology can provide an environmentally friendly geo-engineering method to accelerate ecological restoration and control eutrophication.

2015 ◽  
Vol 38 (2) ◽  
pp. 71-75 ◽  
Author(s):  
Vishnu Aditya ◽  
Asep Koswara ◽  
Nurul Fitriya ◽  
Arief Rachman ◽  
Tumpak Sidabutar ◽  
...  

Harmful algal blooms (HABs) cause various problems, such as water quality degradation, fauna mass mortality and impairment of human health. Water quality monitoring in Lampung Bay has been conducted by Lampung Marine Aquaculture Office (BBL) of the Ministry of Marine Affairs and Fisheries since 1994. Occurrence of Pyrodinium bahamense var. compressum (Pbc), a causative organism of paralytic shellfish poisoning (PSP), has been recorded but threats caused by HABs have never been reported. A study aimed to know the level of public knowledge and awareness about HABs in Lampung Bay has been conducted. The components of group respondents consisted oflocal governments, academics and coastal communities. Awareness from each component was examined includinggeneral HAB knowledge, HAB impact to the community, HAB occurence and local knowledge of HAB. Data of HAB knowledge were collected through questionnaire and focus group  discussion. The result showed that 40.5% of respondents had knowledge of HABs phenomena and 51.3% respondents only know signs or indicators of HAB occurrence, while only 1.4% respondents had knowledge of local HAB occurences. The direct impact of HABs to the community was not commonly known by the respondents. Only a few cases of poisoning after eating seafood were reported. It can be concluded that there was lack of public knowledge and awareness on HABs in LampungBay. Intensive public awareness programs about HABs should be conducted in order to reduce risk towards HABs in Lampung Bay.


2008 ◽  
Vol 42 (1) ◽  
pp. 75-83 ◽  
Author(s):  
Casey Moore

Over the past ten years, efforts to characterize the optical properties of Earth's natural waters have largely merged with the need to better understand underlying biological and chemical processes. Fundamental optical properties such as light level, absorption, scattering and fluorescence are now being utilized with increasing effectiveness to specify particulate and dissolved in-water components in a wide range of applications, including detection of harmful algal blooms, studying ecosystem dynamics, monitoring the effect of industrial and agricultural pollutants, and understanding carbon sequestration processes in the oceans. A diverse offering of commercial optical sensing products capable for research, routine measurements, and in some cases, operational monitoring are now available. These technologies have provided the scientific community with a set of tools for developing, testing, and placing into practice analytical and semi-analytical methods to infer specific biogeochemical parameters and processes. As a result, new, more specialized sensors are now emerging. New sensors couple basic optical property measurements with processing algorithms to provide specific indicators for Harmful Algal Bloom (HAB) identification, carbon products, nutrients, and particle size distributions. The basic measurement methods are described and examples of devices incorporating them are provided to illustrate their use in modern oceanographic research and monitoring.


Toxins ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 407 ◽  
Author(s):  
John R. Harley ◽  
Kari Lanphier ◽  
Esther G. Kennedy ◽  
Tod A. Leighfield ◽  
Allison Bidlack ◽  
...  

Many communities in Southeast Alaska harvest shellfish such as mussels and clams as an important part of a subsistence or traditional diet. Harmful algal blooms (HABs) of phytoplankton such as Alexandrium spp. produce toxins that can accumulate in shellfish tissues to concentrations that can pose a hazard for human health. Since 2013, several tribal governments and communities have pooled resources to form the Southeast Alaska Tribal Ocean Research (SEATOR) network, with the goal of minimizing risks to seafood harvest and enhancing food security. SEATOR monitors toxin concentrations in shellfish and collects and consolidates data on environmental variables that may be important predictors of toxin levels such as sea surface temperature and salinity. Data from SEATOR are publicly available and are encouraged to be used for the development and testing of predictive algorithms that could improve seafood risk assessment in Southeast Alaska. To date, more than 1700 shellfish samples have been analyzed for paralytic shellfish toxins (PSTs) in more than 20 locations, with potentially lethal concentrations observed in blue mussels (Mytilus trossulus) and butter clams (Saxidomus gigantea). Concentrations of PSTs exhibit seasonality in some species, and observations of Alexandrium are correlated to sea surface temperature and salinity; however, concentrations above the threshold of concern have been found in all months, and substantial variation in concentrations of PSTs remain unexplained.


2019 ◽  
Vol 7 (9) ◽  
pp. 288 ◽  
Author(s):  
Bi ◽  
Wang ◽  
Zhang

Dinoflagellates are important primary producers for marine ecosystems and are also responsible for certain essential components in human foods. However, they are also notorious for their ability to form harmful algal blooms, and cause shellfish poisoning. Although much work has been devoted to dinoflagellates in recent decades, our understanding of them at a molecular level is still limited owing to some of their challenging biological properties, such as large genome size, permanently condensed liquid-crystalline chromosomes, and the 10-fold lower ratio of protein to DNA than other eukaryotic species. In recent years, omics technologies, such as genomics, transcriptomics, proteomics, and metabolomics, have been applied to the study of marine dinoflagellates and have uncovered many new physiological and metabolic characteristics of dinoflagellates. In this article, we review recent application of omics technologies in revealing some of the unusual features of dinoflagellate genomes and molecular mechanisms relevant to their biology, including the mechanism of harmful algal bloom formations, toxin biosynthesis, symbiosis, lipid biosynthesis, as well as species identification and evolution. We also discuss the challenges and provide prospective further study directions and applications of dinoflagellates.


2020 ◽  
Author(s):  
Peter W. Schafran ◽  
Victor Cai ◽  
Hsiao-Pei Yang ◽  
Fay-Wei Li

ABSTRACTWater bodies around the world are increasingly threatened by harmful algal blooms (HABs) under current trends of rising water temperature and nutrient load. Metagenomic characterization of HABs can be combined with water quality and environmental data to better understand and predict the occurrence of toxic events. However, standard short-read sequencing typically yields highly fragmented metagenomes, preventing direct connection of genes to a single genome. Using Oxford Nanopore long-read sequencing, we were able to obtain high quality metagenome-assembled genomes, and show that dominant organisms in a HAB are readily identified, though different analyses disagreed on the identity of rare taxa. Genes from diverse functional categories were found not only in the most dominant genera, but also in several less common ones. Using simulated datasets, we show that the Flongle flowcell may provide an option for HAB monitoring with less data, at the expense of failing to detect rarer organisms and increasing fragmentation of the metagenome. Based on these results, we believe that Nanopore sequencing provides a fast, portable, and affordable method for studying HABs.


2021 ◽  
Author(s):  
Ning Ding ◽  
Wenjun Du ◽  
Yanlou Feng ◽  
Yuhao Song ◽  
Chao Wang ◽  
...  

Abstract Harmful algal blooms have deleterious effects on aquatic ecosystems and human health. The application of algicidal bacteria is a promising and environmentally friendly method of preventing and eradicating harmful algal blooms. In this study, a screen for algicidal agents against harmful algal blooms was used to identify an algicidal bacterial strain isolated from a Karenia mikimotoi culture. Strain O-1 exhibited a strong inhibitory effect on harmful K. mikimotoi and was identified as a Paracoccus species via 16S rRNA gene sequence analysis. This strain killed K. mikimotoi by secreting active algicidal compounds, which were stable at temperatures of -80–121 °C, but these substances were sensitive to strongly acidic conditions. The algicidal properties of strain O-1 against K. mikimotoi were cell density- and time-dependent. No significant changes or negative effects were noted for two other Chlorophyta species, which highlighted the specificity of the studied algicidal substance. Finally, single-factor experiments revealed the optimum growth conditions of strain O-1 under different pH and temperature conditions. Strain O-1 therefore has potential as a bio-agent for reducing the biomass of harmful K. mikimotoi blooms.


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