How to measure the occurrence of harmful algal blooms?5 answersThe occurrence of harmful algal blooms (HABs) can be measured using various methods outlined in the research papers. One approach involves utilizing high spatial resolution satellite images to detect spectral features indicative of red tide phenomena, such as changes in reflectance values. Additionally, a system incorporating Surface Plasmon Resonance (SPR) and water quality parameter sensors has been developed to automatically detect red tide toxins and water quality parameters, providing a faster and more efficient way of detecting and predicting HAB occurrences. Furthermore, a region-based analysis focusing on factors contributing to cyanobacteria concentration in lakes suggests the use of Vector Autoregressive (VAR) / Vector Error Correction Model (VECM) and ARIMAX models for forecasting bloom formation, with Surface Temperature (ST) identified as a key factor in certain regions.
How many bleaching events in the red sea?4 answersThere have been multiple bleaching events in the Red Sea. The northern Red Sea experienced three mesophotic-specific coral bleaching events over the course of eight years, resulting in a decline in coral populations and a shift in community structure. In 2015, a major bleaching event occurred in the central Saudi Arabian Red Sea, impacting a large number of reefs, with bleaching most prevalent on inshore reefs and shallower transects. A boreal winter bleaching event was observed in January 2020 in the central Red Sea, mainly affecting the branching coral Stylophora pistillata on an offshore reef flat. Another major bleaching event occurred in the central Red Sea in the summer of 2010, resulting in variable mortality among coral taxa and significant changes in community composition. Additionally, evidence of previously unknown bleaching events in 1931, 1978, and 1982 was found in the Saudi Arabian central Red Sea, with the frequency and severity of bleaching events since 1998 being unprecedented.
Which algae species are known to cause health problems in humans?4 answersAlgae species known to cause health problems in humans include both marine and freshwater algae. These algae can produce toxins that can lead to various symptoms and even death when consumed or exposed to. The major route of human exposure to algal toxins is through the consumption of contaminated seafood products, while exposure to cyanobacterial toxins is generally through direct contact or drinking water supplies. Some edible algae species, such as Hizikia fusiform alga, can accumulate high concentrations of inorganic arsenic, making it necessary to modulate their consumption. It is also recommended to avoid consuming algae from places with a higher degree of contamination and to vary between species to avoid excessive exposure to toxic elements. Shewanella algae, a Gram-negative bacterium, is considered an emerging human pathogen and has been associated with various risk factors in patients. Cyanobacteria, including blue-green algae, can negatively affect human health by being toxic, allergenic, and pathogenic. They can be found in the built environment, including the air, surfaces, and water bodies.
Whats the syndroms associated with harmful algae4 answersHarmful algal blooms (HABs) can cause several syndromes associated with human health risks. These include ciguatera poisoning, paralytic shellfish poisoning (PSP), neurotoxic shellfish poisoning (NSP), amnesic shellfish poisoning (ASP), and diarrhetic shellfish poisoning (DSP). These syndromes result from exposure to different toxins or toxin congeners, but they share common clinical features. Exposure to HABs can occur through the consumption of contaminated seafood or through exposure to aerosolized NSP toxins. Routine clinical tests are not available for the diagnosis of HAB-related illnesses, and there is no known antidote for exposure. The spread of HABs is influenced by anthropogenic activities and climate change, which can lead to increased risks to human health. To minimize these risks, further research, communication, and collaboration among HAB scientists, public health researchers, and health departments are needed. Improvements in toxin detection methods and surveillance programs are also important in limiting human exposure to shellfish toxins.
Are there toxic compounds in algae?5 answersAlgae can contain toxic compounds, including heavy metals and organic pollutants, which can have negative effects on the environment and human health. These toxic compounds can accumulate in algae through various sources such as industrial and domestic pollution. Some species of algae, such as Hizikia fusiform alga, have been found to accumulate high concentrations of inorganic arsenic, making it necessary to regulate their consumption. Additionally, algae can produce bioactive compounds, some of which can be toxic, such as okadaic acid, ciguatoxin, and maitotoxin. The presence of toxic compounds in algae highlights the importance of monitoring and regulating their use in industries such as pharmaceuticals, cosmetics, and food.
What are the mechanisms of harmful algal blooms?3 answersHarmful algal blooms (HABs) can occur due to various mechanisms. One mechanism is the production of toxins by certain species of algae, which can pose threats to human health, mariculture industry, and natural ecosystems. Another mechanism is allelopathy, where some toxins produced by microalgae suppress the growth of competitors, potentially leading to algal blooms. However, recent meta-analysis suggests that allelopathy may not be a significant factor in bloom formation, as allelopathic effects were only observed at very high cell densities typical of blooms. Other factors that can contribute to the occurrence of HABs include coastal eutrophication, long-term changes in hydrological and meteorological parameters, and the adaptive and competitive strategies of HAB causative species. Additionally, the imbalance of nutrient loads, not in proportion to the Redfield ratio, can also promote the growth of harmful algae.