oceany: Harmful algal bloom

Evidence: 100 • authority: 72

A harmful algal bloom (HAB), or excessive algae growth, sometimes called a red tide in marine environments, is an algal bloom that causes negative impacts to other organisms by production of natural algae-produced toxins, water deoxygenation, mechanical damage to other organisms, or by other means. HABs are sometimes defined as only those algal blooms that produce toxins, and sometimes as any algal bloom that can result in severely lower oxygen levels in natural waters, killing organisms in marine or fresh waters. Blooms can last from a few days to many months. After the bloom dies, the microbes that decompose the dead algae use up more of the oxygen, generating a "dead zone" which can caus…

Evidence: 72 • authority: 72

An algal bloom or algae bloom is a rapid increase or accumulation in the population of algae in fresh water or marine water systems. It may be a benign or harmful algal bloom. Algal bloom is often recognized by the discoloration in the water from the algae's pigments. The term algae encompasses many types of aquatic photosynthetic organisms, both macroscopic multicellular organisms like seaweed and microscopic unicellular organisms like cyanobacteria. Algal bloom commonly refers to the rapid growth of microscopic unicellular algae, not macroscopic algae. An example of a macroscopic algal bloom is a kelp forest. Algal blooms are the result of a nutrient, like nitrogen or phosphorus from vari…

Evidence: 58 • authority: 80

Overview: Harmful algal blooms and natural toxins in fresh and marine waters – Exposure, occurrence, detection, toxicity, control, management and policy

Evidence: 55 • authority: 72

Cyanotoxins are toxins produced by cyanobacteria (also known as blue-green algae). Cyanobacteria are found almost everywhere, but particularly in lakes and in the ocean where, under high concentration of phosphorus conditions, they reproduce exponentially to form blooms. Blooming cyanobacteria can produce cyanotoxins in such concentrations that they can poison and even kill animals and humans. Cyanotoxins can also accumulate in other animals such as fish and shellfish, and cause poisonings such as shellfish poisoning. Some of the most powerful natural poisons known are cyanotoxins. They include potent neurotoxins, hepatotoxins, cytotoxins, and endotoxins. The cyano in the term cyanobacteria…

Evidence: 54 • authority: 88

Workshop on the socio-economic effects of marine and fresh water harmful algal blooms in the United States. The US National Office for Harmful Algal Blooms at the Woods Hole Oceanographic Institution (WHOI) and the NOAA National Centers for Coastal Ocean Science (NCCOS) held a virtual workshop comprising four sessions between July 27 and August 5, 2020. This report summarizes the workshop proceedings and presents recommendations developed by participants during the discussion. The recommendations advance an assessment framework and a national research agenda that will lead to comprehensive evaluations of the socio-economic effects of harmful algal blooms (HABs) in fresh water (primarily the…

Evidence: 50 • authority: 72

Anoxic waters are bodies or areas of sea water, fresh water or groundwater that are depleted of dissolved oxygen. Anoxic waters can be contrasted with hypoxic waters, which are low but not completely lacking in dissolved oxygen, often defined as having oxygen concentration less than 2 milligrams per litre. This condition is generally found in areas that have water stagnation and/or dead stratification. The United States Geological Survey defines anoxic groundwater as that with a dissolved oxygen concentration of less than 0.5 milligrams per litre. In most cases, oxygen diffusion is prevented from the shallower photic zone to deeper levels by a physical barrier, as well as by pronounced stra…

Evidence: 49 • authority: 72

Eutrophication is a general term describing a process in which nutrients accumulate in a body of water, resulting in an increased growth of organisms that may deplete the oxygen in the water; i.e. the process of too many plants growing on the surface of a river, lake, etc., often because chemicals that are used to help crops grow have been carried there by rain. Eutrophication may occur naturally or as a result of human actions. Manmade, or cultural, eutrophication occurs when sewage, industrial wastewater, fertilizer runoff, and other nutrient sources are released into the environment. Such nutrient pollution usually causes algal blooms and bacterial growth, resulting in the depletion of d…

Evidence: 45 • authority: 92

Temperature effects on productivity, respiration, and dissolved organic matter degradation in subtropical Florida waters following hurricane-driven riverine runoff and brownification.. Increasing ocean warming and storm-driven terrestrial inputs are reshaping subtropical coastal ecosystems. This study investigated how elevated temperature and humic acid enrichment, under both pre- and post-hurricane (Idalia, Debby, Helene and Milton) in situ and manipulated conditions, affect the metabolic rates of phytoplankton communities on the West Florida Shelf (WFS). We hypothesized that warming, combined with hurricane-driven humic inputs, would decrease primary production rates while enhancing respi…

Evidence: 44 • authority: 80

Harmful Algal Blooms (HABs) in coastal waters and their management

Evidence: 39 • authority: 92

Probable Microcystin Toxicosis in a Red-Gartered Coot (<i>Fulica armillata</i>) from a Protected Coastal Wetland in Central Chile-A Sentinel for Toxic Cyanobacterial Bloom?. Cyanobacterial harmful algal blooms are an increasing concern for wildlife health, particularly in eutrophic wetlands, yet well-documented avian cases supported by environmental, pathological, and toxicological evidence remain scarce. This study describes a sentinel case of probable microcystin toxicosis in a Red-gartered coot ( Fulica armillata ) from Laguna Petrel, a protected coastal wetland in central Chile, during a broader wildlife mortality event. Surface-water monitoring included nutrient analyses, i…

Evidence: 39 • authority: 92

Algal Betaine Triggers Bacterial Hydrogen Peroxide Production that Promotes Algal Demise.. Hydrogen peroxide (H 2 O 2 ) plays various roles in the ocean, acting as a signaling molecule at low concentrations and causing oxidative stress when accumulated. Here, we use transcriptomics, genetics, and metabolomics to study H 2 O 2 dynamics in the interaction between Emiliania huxleyi algae and Phaeobacter inhibens bacteria. We find that H 2 O 2 levels rise during algal death and that bacterial H 2 O 2 production triggers this demise. In co-cultures, but not in axenic algal cultures, chemically reducing H 2 O 2 levels prevents algal death, whereas chemically increasing H 2 O 2 levels accelerates…

Evidence: 39 • authority: 92

Revisiting harmful algal blooms in India through a global lens: An integrated framework for enhanced research and monitoring.. Harmful algal bloom (HAB) events substantially impact human and aquatic ecosystem health and the global blue economy; hence, a concerted effort is required to advance our understanding of HAB ecology to better inform monitoring and mitigation measures. Here, we highlight the current state of HAB research and monitoring in India, where ∼17% of the human population resides in the vicinity of its long coastline and is dependent on the sustainable blue economy. Through the lens of established programs from countries across the globe, we identify existing gaps and highli…