scholarly journals Distribution of Harmful Algal Growth-Limiting Bacteria on Artificially Introduced Ulva and Natural Macroalgal Beds

2020 ◽  
Vol 10 (16) ◽  
pp. 5658
Author(s):  
Nobuharu Inaba ◽  
Isamu Kodama ◽  
Satoshi Nagai ◽  
Tomotaka Shiraishi ◽  
Kohei Matsuno ◽  
...  
Keyword(s):  
Biological Control ◽  
Harmful Algal Blooms ◽  
Algal Blooms ◽  
Algal Growth ◽  
Macroalgal Species ◽  
Chattonella Antiqua ◽  
Cultured Fish ◽  
Wet Weight ◽  
Artificial Introduction ◽  
Hab Species

The intensity and frequency of harmful algal blooms (HABs) have increased, posing a threat to human seafood resources due to massive kills of cultured fish and toxin contamination of bivalves. In recent years, bacteria that inhibit the growth of HAB species were found to be densely populated on the biofilms of some macroalgal species, indicating the possible biological control of HABs by the artificial introduction of macroalgal beds. In this study, an artificially created Ulva pertusa bed using mobile floating cages and a natural macroalgal bed were studied to elucidate the distribution of algal growth-limiting bacteria (GLB). The density of GLB affecting fish-killing raphidophyte Chattonella antiqua, and two harmful dinoflagellates, were detected between 106 and 107 CFU g−1 wet weight on the biofilm of artificially introduced U. pertusa and 10 to 102 CFU mL−1 from adjacent seawater; however, GLB found from natural macroalgal species targeted all tested HAB species (five species), ranging between 105 and 106 CFU g−1 wet weight in density. These findings provide new ecological insights of GLB at macroalgal beds, and concurrently demonstrate the possible biological control of HABs by artificially introduced Ulva beds.

scholarly journals Promotion of harmful algal blooms by zooplankton predatory activity

2006 ◽  
Vol 2 (2) ◽  
pp. 194-197 ◽  
Author(s):  
Aditee Mitra ◽  
Kevin J Flynn
Keyword(s):  
Harmful Algal Blooms ◽  
Algal Blooms ◽  
Harmful Algal Bloom ◽  
Algal Species ◽  
Algal Growth ◽  
Nutrient Stress ◽  
Nutrient Ratios ◽  
Predator Prey ◽  
Predator Prey Model ◽  
Hab Species

The relationship between algae and their zooplanktonic predators typically involves consumption of nutrients by algae, grazing of the algae by zooplankton which in turn enhances predator biomass, controls algal growth and regenerates nutrients. Eutrophication raises nutrient levels, but does not simply increase normal predator–prey activity; rather, harmful algal bloom (HAB) events develop often with serious ecological and aesthetic implications. Generally, HAB species are outwardly poor competitors for nutrients, while their development of grazing deterrents during nutrient stress ostensibly occurs too late, after the nutrients have largely been consumed already by fast-growing non-HAB species. A new mechanism is presented to explain HAB dynamics under these circumstances. Using a multi-nutrient predator–prey model, it is demonstrated that these blooms can develop through the self-propagating failure of normal predator–prey activity, resulting in the transfer of nutrients into HAB growth at the expense of competing algal species. Rate limitation of this transfer provides a continual level of nutrient stress that results in HAB species exhibiting grazing deterrents protecting them from top-down control. This process is self-stabilizing as long as nutrient demand exceeds supply, maintaining the unpalatable status of HABs; such events are most likely under eutrophic conditions with skewed nutrient ratios.

Biological control of harmful algal blooms: A modelling study

2006 ◽  
Vol 61 (3-4) ◽  
pp. 165-179 ◽  
Author(s):  
Jordi Solé ◽  
Marta Estrada ◽  
Emilio Garcia-Ladona
Keyword(s):  
Biological Control ◽  
Harmful Algal Blooms ◽  
Algal Blooms ◽  
Modelling Study

scholarly journals Effects of Mixed Allelochemicals on the Growth of Microcystis aeruginosa, Microcystin Production, Extracellular Polymeric Substances, and Water Quality

Water ◽  
2020 ◽  
Vol 12 (7) ◽  
pp. 1861
Author(s):  
Ping Ouyang ◽  
Chao Wang ◽  
Peifang Wang ◽  
Xiaorong Gan ◽  
Xun Wang ◽  
...  
Keyword(s):  
Ethyl Acetate ◽  
Malonic Acid ◽  
Harmful Algal Blooms ◽  
Algal Blooms ◽  
Extracellular Polymeric Substances ◽  
Algal Growth ◽  
Sharp Decrease ◽  
Inorganic Phosphorus ◽  
Nonanoic Acid ◽  
Control Group

The inhibition of cyanobacteria growth by allelochemicals, which controls harmful algal blooms has been examined in many studies. The objective of this work was to compare the efficiencies of different allelochemicals and determine a mixing proportion corresponding to the highest algae inhibiting activity and smallest adverse effect. The obtained results demonstrated that artemisinin, nonanoic acid, malonic acid, and ethyl acetate inhibited algal growth more efficiently than D-menthol and lactic acid. Synergies were observed in five groups of allelochemical combinations with inhibition ratios exceeding 80%, and the concentrations of extracellular microcystin-LR in the groups with high algal inhibition ratios were lower than that in the control group on the 7th day. No changes in extracellular polymeric substances compositions were detected after treatment. The permanganate indices of the treated groups were higher than that of the control group; however, this disparity gradually decreased with time. In addition, a sharp decrease in the concentration of dissolved inorganic phosphorus was observed for all treated groups. From the obtained data, the optimal proportion of mixed allelochemicals corresponding to 3.94 mg L−1 of artemisinin, 6.27 mg L−1 of nonanoic acid, 8.2 mg L−1 of malonic acid, and 6.38 mg L−1 of ethyl acetate was suggested.

Unprecedented toxic algal blooms impact on Tasmanian seafood industry

2016 ◽  
Vol 37 (3) ◽  
pp. 143 ◽  
Author(s):  
Gustaaf Hallegraeff ◽  
Christopher Bolch
Keyword(s):  
Harmful Algal Blooms ◽  
Algal Blooms ◽  
East Coast ◽  
Economic Losses ◽  
Human Society ◽  
Rock Lobster ◽  
Negative Effects ◽  
Risk Area ◽  
Seafood Industry ◽  
Hab Species

While most microscopic algae provide food for filter-feeding shellfish and larvae of crustaceans and finfish, other so-called Harmful Algal Blooms (HABs) can have negative effects, causing severe economic losses to aquaculture, fisheries and tourism. Of greatest concern to human society are blooms of toxic HAB species that cause illness and death of fish, seabirds and mammals via toxins transferred through the food web. Unprecedented Alexandrium (Dinophyceae) blooms along the East Coast of Tasmania in 2012 and 2015, a previously low biotoxin risk area, led to major impacts on the local oyster, mussel, scallop and rock lobster industries. Four human hospitalisations also occurred from eating wild shellfish.

Occurrence characteristics of harmful and non-harmful algal species related to coastal environments in the southern sea of Korea

2019 ◽  
Vol 70 (6) ◽  
pp. 794 ◽  
Author(s):  
Jin Ho Kim ◽  
Minji Lee ◽  
Young Kyun Lim ◽  
Yun Ji Kim ◽  
Seung Ho Baek
Keyword(s):  
South Korea ◽  
Harmful Algal Blooms ◽  
Algal Blooms ◽  
Phytoplankton Community ◽  
Algal Species ◽  
Coastal Environments ◽  
Survey Period ◽  
Offshore Area ◽  
Occurrence Characteristics ◽  
Hab Species

Because the phytoplankton community and blooms are regulated by various environmental factors, it is difficult to define the cause and occurrence of the phenomenon of harmful algal blooms (HABs). This study evaluated the phytoplankton community and occurrence characteristic of HAB species related to coastal environments in South Korea, 2016. In summer, because of strong upwelling event, the surface sweater temperature around Geoje Island was abnormally low (17°C), and an unusual high temperature (29°C) and low salinity (29psu) were measured in offshore area. Diatoms and dinoflagellates showed contrasting occurrences during the survey period. Diatoms were dominant in the inshore area, whereas dinoflagellates occurred in the offshore area. The phytoplankton-community structures were established depending on different hydro-oceanographic characteristics. In statistical analysis, HABs of dinoflagellate Karenia appeared in upwelling areas with a high nutritional content, whereas Gymnodinium, Gyrodinium and Prorocentrum appeared in areas of low nutrients in June, and HAB species showed an equivalent tendency to appear at high water temperature and low saline level in August. Our results indicated that hydro-oceanographic events such as river discharge, current and upwelling play important roles in determining the phytoplankton community and potential occurrence characteristics of HABs in the coastal environment of South Korea.

What Happened in 1950?

Dead Zones ◽  
2021 ◽  
pp. 52-71
Author(s):  
David L. Kirchman
Keyword(s):  
Gulf Of Mexico ◽  
Mississippi River ◽  
Organic Material ◽  
Harmful Algal Blooms ◽  
Algal Blooms ◽  
Mark Twain ◽  
Dead Zone ◽  
Algal Growth ◽  
Fish Kills ◽  
Dead Zones

This chapter discusses what happened around 1950 that led to the expansion of dead zones. For the Gulf of Mexico, there are many reasons to think the flow of the Mississippi River has changed since the days of Mark Twain, considering the construction of so many levees, dikes, floodways, spillways, weirs, and revetments. Rain-absorbing grasslands and forests have been replaced by asphalt, roof shingles, and other hydrophobic material that hasten rainwater to the Gulf. But the flow of the Mississippi has not changed enough to explain why the Gulf dead zone grew around 1950. As the chapter discusses, what did change was nutrients. It shows that concentrations doubled in the Mississippi River from the 1930s to the 1990s, which stimulated algal growth and production of organic material that eventually led to depletion of dissolved oxygen. In addition to creating dead zones, the increase in nutrients has stimulated harmful algal blooms, leading to fish kills and beach closings.

scholarly journals Spatiotemporal Distribution of Harmful Algal Flora in the Tropical Estuarine Complex of Goa, India

2012 ◽  
Vol 2012 ◽  
pp. 1-11 ◽  
Author(s):  
Suraksha M. Pednekar ◽  
S. G. Prabhu Matondkar ◽  
Vijaya Kerkar
Keyword(s):  
Harmful Algal Blooms ◽  
Algal Blooms ◽  
Nutrient Loading ◽  
Algal Species ◽  
Spatiotemporal Variability ◽  
Algal Flora ◽  
The Past ◽  
Tropical Estuarine ◽  
Mandovi And Zuari Estuaries ◽  
Hab Species

Mandovi and Zuari estuarine complex is monsoon-influenced estuaries located along the central west coast of India. During the past few years, there has been an increase in nutrient loading specially during monsoonal runoff which is responsible for the growth of harmful algal flora. To understand occurrence and distribution of harmful algal blooms species, daily/alternate day samplings were carried out in Mandovi and Zuari estuaries during 2007-2008 and 2008-2009 periods, respectively, comprising of monsoon (June–November) and nonmonsoon (December–May). In Mandovi, total 54 HAB species with 49 in monsoon and 36 during nonmonsoon period were reported. In Zuari, total 46 HAB species with 38 in monsoon and 41 were reported during nonmonsoon period. Bray-Curtis cluster analysis based on log-transformed phytoplankton density detected seven well-defined groups revealing spatiotemporal variability. The density of the dominant harmful algal species was significantly positively correlated with nutrients, but negatively correlated with salinity. The results of the study indicate that monsoon plays an important role in occurrence and distribution of harmful algal species having direct correlation with salinity variations and nutrient loading.

scholarly journals Fiber-Optic Microarray for Simultaneous Detection of Multiple Harmful Algal Bloom Species

2006 ◽  
Vol 72 (9) ◽  
pp. 5742-5749 ◽  
Author(s):  
Soohyoun Ahn ◽  
David M. Kulis ◽  
Deana L. Erdner ◽  
Donald M. Anderson ◽  
David R. Walt
Keyword(s):  
Harmful Algal Blooms ◽  
Algal Blooms ◽  
Fiber Optic ◽  
Harmful Algal Bloom ◽  
Simultaneous Detection ◽  
Cross Reactivity ◽  
Detection Methods ◽  
Sandwich Hybridization ◽  
Field Samples ◽  
Hab Species

ABSTRACT Harmful algal blooms (HABs) are a serious threat to coastal resources, causing a variety of impacts on public health, regional economies, and ecosystems. Plankton analysis is a valuable component of many HAB monitoring and research programs, but the diversity of plankton poses a problem in discriminating toxic from nontoxic species using conventional detection methods. Here we describe a sensitive and specific sandwich hybridization assay that combines fiber-optic microarrays with oligonucleotide probes to detect and enumerate the HAB species Alexandrium fundyense, Alexandrium ostenfeldii, and Pseudo-nitzschia australis. Microarrays were prepared by loading oligonucleotide probe-coupled microspheres (diameter, 3 μm) onto the distal ends of chemically etched imaging fiber bundles. Hybridization of target rRNA from HAB cells to immobilized probes on the microspheres was visualized using Cy3-labeled secondary probes in a sandwich-type assay format. We applied these microarrays to the detection and enumeration of HAB cells in both cultured and field samples. Our study demonstrated a detection limit of approximately 5 cells for all three target organisms within 45 min, without a separate amplification step, in both sample types. We also developed a multiplexed microarray to detect the three HAB species simultaneously, which successfully detected the target organisms, alone and in combination, without cross-reactivity. Our study suggests that fiber-optic microarrays can be used for rapid and sensitive detection and potential enumeration of HAB species in the environment.

scholarly journals Phosphorus Non-Point Pollution from Equestrian Wastes and the Need for Recycling

2021 ◽  
Vol 10 (2) ◽  
pp. 61
Author(s):  
J. William Louda ◽  
Bobby G. Duersch ◽  
Jeffrey T. Osetek ◽  
Charmaine Cintron ◽  
Lorraine Chaljub ◽  
...  
Keyword(s):  
Harmful Algal Blooms ◽  
Algal Blooms ◽  
Organic Phosphorus ◽  
Dry Weight ◽  
Pollution Source ◽  
South Florida ◽  
Horse Manure ◽  
Pasture Grasses ◽  
Wet Weight ◽  
Extractable Phosphorus

South Florida and much of the rest of the World suffers from harmful algal blooms (HABs) and controls of both nitrogen (N) and phosphorus (P) pollution are required to curtail the onset, spread and/or expansion of these blooms. This report covers our studies on several aspects of equestrian waste (viz. horse manure) aimed at yielding an overview of phosphorus and its pollution stemming from non-point horse manure sources in portions of Palm Beach County Florida. Methods included a modified Hedley extraction sequence, emphasizing ‘easily extractable phosphorus’ (EEP), and 31P nuclear magnetic resonance (NMR) spectroscopic identification of organic phosphorus (Po) species. Samples included fresh and aged horse manure, pasture soils, horse feed and pasture grasses, and canal waters adjacent to equestrian or agricultural fields. Easily extractable Phosphorus (EEP) averaged about 54-77% of the total horse manure phosphorus. Total phosphorus ranged from 13,020 – 22,300 mg per kilogram dry weight. (≈60-100 lbs. P2O5 / ton and on a wet weight basis, this equates to 4,000 to 14,818 grams-P/ U.S. ton or 8.8 to 32.6 pounds of phosphorus (≈ 20-75 lb. P2O5) per wet weight ton of horse manure. Considering the values of EEP in fresh samples from a single horse, we found a range of 8,000 – 17,000 mg-P/kg (8-17 g-P/kg) dry weight horse manure. Soil samples yielded the highest P in the NaOH extract of the Hedley sequence. This equates to the Al, Fe and ester forms. Phosphorus (viz. EEP) runoff is viewed here as a non-point P pollution source.

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