scholarly journals A prolonged red tide of Heterocapsa triquetra (Ehrenberg) F. Stein (Dinophyceae) and phytoplankton succession in a eutrophic estuary in Turkey

2015 ◽  
Vol 16 (3) ◽  
pp. 621 ◽  
Author(s):  
S. TAS
Keyword(s):  
Harmful Algal Blooms ◽  
Algal Blooms ◽  
Red Tide ◽  
Prorocentrum Minimum ◽  
Phytoplankton Succession ◽  
Chl A ◽  
Heterocapsa Triquetra ◽  
Golden Horn ◽  
Moderate Salinity ◽  
Near Future

A prolonged red tide of Heterocapsa triquetra and phytoplankton succession were investigated in a eutrophic estuary (Golden Horn) for a year. Runoff following the rainfall in winter supplied high amounts of nutrients and also created a mesohaline frontal zone in the middle and upper estuary. Red tide of H. triquetra was first observed with an orange-brownish water discoloration at the upper estuary in January. Highest cell density of H. triquetra was 2.7×106 cells l-1 in January and reached to 19.2×106 cells l-1 in April. Successive blooms continued with dinoflagellate Prorocentrum minimum in May and phytoflagellates Eutreptiella marina and Fibrocapsa sp. in summer. High chl-a and dissolved oxygen were measured in the spring depending on algal biomass. Findings indicate that H. triquetra might be adapted to moderate salinity and low temperatures and red tide events should be considered as a response to increasing eutrophication due to high amounts of nutrients. Eutrophication can lead to harmful algal blooms for this area in the near future.

scholarly journals Unsteady Multi-Element Time Series Analysis and Prediction Based on Spatial-Temporal Attention and Error Forecast Fusion

2020 ◽  
Vol 12 (2) ◽  
pp. 34
Author(s):  
Xiaofan Wang ◽  
Lingyu Xu
Keyword(s):  
Harmful Algal Blooms ◽  
Algal Blooms ◽  
Short Term Memory ◽  
Sudden Change ◽  
Back Propagation ◽  
Red Tides ◽  
Model Errors ◽  
Chl A ◽  
Error Forecast ◽  
Concentration Prediction

Harmful algal blooms (HABs) often cause great harm to fishery production and the safety of human lives. Therefore, the detection and prediction of HABs has become an important issue. Machine learning has been increasingly used to predict HABs at home and abroad. However, few of them can capture the sudden change of Chl-a in advance and handle the long-term dependencies appropriately. In order to address these challenges, the Long Short-Term Memory (LSTM) based spatial-temporal attentions model for Chlorophyll-a (Chl-a) concentration prediction is proposed, a model which can capture the correlation between various factors and Chl-a adaptively and catch dynamic temporal information from previous time intervals for making predictions. The model can also capture the stage of Chl-a when values soar as red tide breaks out in advance. Due to the instability of the current Chl-a concentration prediction model, the model is also applied to make a prediction about the forecast reliability, to have a basic understanding of the range and fluctuation of model errors and provide a reference to describe the range of marine disasters. The data used in the experiment is retrieved from Fujian Marine Forecasts Station from 2009 to 2011 and is combined into 8-dimension data. Results show that the proposed approach performs better than other Chl-a prediction algorithms (such as Attention LSTM and Seq2seq and back propagation). The result of error prediction also reveals that the error forecast method possesses established advantages for red tides prevention and control.

scholarly journals Tracing the sources of nutrients fueling dinoflagellate red tides occurring along the coast of Korea using radium isotopes

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Hyeong Kyu Kwon ◽  
Guebuem Kim ◽  
Yongjin Han ◽  
Junhyeong Seo ◽  
Weol Ae Lim ◽  
...  
Keyword(s):  
Harmful Algal Blooms ◽  
Algal Blooms ◽  
Red Tide ◽  
Subsurface Layer ◽  
Vertical Mixing ◽  
Eastern Coast ◽  
Nutrient Concentrations ◽  
Red Tides ◽  
Radium Isotopes ◽  
Nutrient Sources

Abstract It is a well held concept that the magnitude of red-tide occurrence is dependent on the amount of nutrient supply if the conditions are same for temperature, salinity, light, interspecific competition, etc. However, nutrient sources fueling dinoflagellate red-tides are difficult to identify since red tides usually occur under very low inorganic-nutrient conditions. In this study, we used short-lived Ra isotopes (223Ra and 224Ra) to trace the nutrient sources fueling initiation and spread of Cochlodinium polykrikoides blooms along the coast of Korea during the summers of 2014, 2016, and 2017. Horizontal and vertical distributions of nutrient concentrations correlated well with 224Ra activities in nutrient-source waters. The offshore red-tide areas showed high 224Ra activities and low-inorganic and high-organic nutrient concentrations, which are favorable for blooming C. polykrikoides in competition with diatoms. Based on Ra isotopes, the nutrients fueling red-tide initiation (southern coast of Korea) are found to be transported horizontally from inner-shore waters. However, the nutrients in the spread region (eastern coast of Korea), approximately 200 km from the initiation region, are supplied continuously from the subsurface layer by vertical mixing or upwelling. Our study highlights that short-lived Ra isotopes are excellent tracers of nutrients fueling harmful algal blooms in coastal waters.

scholarly journals Harmful algal blooms and red tide problems on the U.S. west coast

1997 ◽  
Vol 42 (5part2) ◽  
pp. 1076-1088 ◽  
Author(s):  
Rita A. Horner ◽  
David L. Garrison ◽  
F. Gerald Plumley
Keyword(s):  
West Coast ◽  
Harmful Algal Blooms ◽  
Algal Blooms ◽  
Red Tide ◽  
The U.S

scholarly journals Action Plan for Monitoring, Mitigation and Management of Harmful Algal Blooms in the Coastal Waters of Oman

2007 ◽  
Vol 12 (2) ◽  
pp. 75
Author(s):  
A.Y.A AlKindi ◽  
H.M.H. Al-Ghelani ◽  
S. Amer ◽  
Y.K Al-Akhzami
Keyword(s):  
Coastal Waters ◽  
Harmful Algal Blooms ◽  
Algal Blooms ◽  
Red Tide ◽  
Action Plan ◽  
Rapid Response System ◽  
Gulf Of Oman ◽  
Trichodesmium Erythraeum ◽  
Response System ◽  
Adverse Impacts

The Gulf of Oman, an ecologically and economically rich ecosystem, is frequently impacted by occurrences of harmful algal blooms. Recent studies indicate an increase in the number of causative species and harmful impacts. Many red tide incidents in Oman have been found leading to hypoxia. The frequent bloom forming species here are Karenia selliformis, Nitzschia pungens, Prorocentrum arabianum and Trichodesmium erythraeum. We review work carried out in this area, and we propose here a Management Action Plan for not only an effective monitoring system for harmful algal blooms (HABs), but also mitigation of their adverse impacts and rapid response system.   

scholarly journals Fish Kill Incidents and Harmful Algal Blooms in Omani Waters

2011 ◽  
Vol 16 ◽  
pp. 23 ◽  
Author(s):  
Hamed Mohammed Al Gheilani ◽  
Kazumi Matsuoka ◽  
Abdulaziz Yahya AlKindi ◽  
Shehla Amer ◽  
Colin Waring
Keyword(s):  
Harmful Algal Blooms ◽  
Algal Blooms ◽  
Red Tide ◽  
Ecological Impacts ◽  
Red Tides ◽  
Fish Kill ◽  
Noctiluca Scintillans ◽  
Trichodesmium Erythraeum ◽  
Toxic Species ◽  
Desalination Plants

Red tide, one of the harmful algal blooms (HABs) is a natural ecological phenomenon and often this event is accompanied by severe impacts on coastal resources, local economies, and public health. The occurrence of red tides has become more frequent in Omani waters in recent years. Some of them caused fish kill, damaged fishery resources and mariculture, threatened the marine environment and the osmosis membranes of desalination plants. However, a number of them have been harmless. The most common dinoflagellate Noctiluca scintillans is associated with the red tide events in Omani waters. Toxic species like Karenia selliformis, Prorocentrum arabianum, and Trichodesmium erythraeum have also been reported recently. Although red tides in Oman have been considered a consequence of upwelling in the summer season (May to September), recent phytoplankton outbreaks in Oman are not restricted to summer. Frequent algal blooms have been reported during winter (December to March). HABs may have contributed to hypoxia and/or other negative ecological impacts. 

scholarly journals The Use of Sentinel-3 Imagery to Monitor Cyanobacterial Blooms

Environments ◽  
2019 ◽  
Vol 6 (6) ◽  
pp. 60 ◽  
Author(s):  
Igor Ogashawara
Keyword(s):  
Remote Sensing ◽  
Harmful Algal Blooms ◽  
Algal Blooms ◽  
Lake Erie ◽  
Water Governance ◽  
Spectral Band ◽  
Cyanobacterial Blooms ◽  
Chl A ◽  
Cyanobacterial Harmful Algal Blooms ◽  
New Algorithms

Cyanobacterial harmful algal blooms (CHABs) have been a concern for aquatic systems, especially those used for water supply and recreation. Thus, the monitoring of CHABs is essential for the establishment of water governance policies. Recently, remote sensing has been used as a tool to monitor CHABs worldwide. Remote monitoring of CHABs relies on the optical properties of pigments, especially the phycocyanin (PC) and chlorophyll-a (chl-a). The goal of this study is to evaluate the potential of recent launch the Ocean and Land Color Instrument (OLCI) on-board the Sentinel-3 satellite to identify PC and chl-a. To do this, OLCI images were collected over the Western part of Lake Erie (U.S.A.) during the summer of 2016, 2017, and 2018. When comparing the use of traditional remote sensing algorithms to estimate PC and chl-a, none was able to accurately estimate both pigments. However, when single and band ratios were used to estimate these pigments, stronger correlations were found. These results indicate that spectral band selection should be re-evaluated for the development of new algorithms for OLCI images. Overall, Sentinel 3/OLCI has the potential to be used to identify PC and chl-a. However, algorithm development is needed.

Preliminary Development of a Competitive Fluorescent Quantum Dot-Based Immunochromatographic Test Strip for Sensitive Saxitoxin Detection

2020 ◽  
Vol 18 (6) ◽  
pp. 459-463
Author(s):  
John G. Bruno ◽  
Jeremy John
Keyword(s):  
Harmful Algal Blooms ◽  
Algal Blooms ◽  
Dynamic Range ◽  
Red Tide ◽  
Coupling Reaction ◽  
Test Strip ◽  
Paralytic Shellfish Poisoning ◽  
Shellfish Poisoning ◽  
Band Shift ◽  
Portable Detection

Rapid and portable detection of saxitoxin (STX) and its many congeners is highly desirable to prevent paralytic shellfish poisoning due to red tide or harmful algal blooms. In this work, we describe successful preliminary efforts to develop a very sensitive general STX family test strip employing highly fluorescent red quantum dots (Qdot 655) to detect as little as 0.5 to 1 part per billion (ppb or ng/ml) of STX with a dynamic range extending to 20,000 ppb after the prototype dipstick assay was optimized. A competitive format was necessitated by the small molecule nature of STXs having only one epitope, but the decrease in Qdot fluorescence was clearly visible to the naked eye as a function of increasing STX concentration in aqueous buffer. The competitive displacement assay format required conjugation of a primary amine in STX to carboxyl-Qdot 655 via a covalent carbodiimide coupling reaction which was validated by an electrophoretic mobility band shift assay.

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