Harmful Algal Bloom

Definition

Harmful algal blooms (HABs) are proliferations of certain noxious and/or toxic micro- and macroalgae and cyanobacteria, regardless of their concentration, with negative impacts on aquatic ecosystems, and human health and wellbeing. HABs are naturally occurring phenomena that are also facilitated by anthropogenic pressures (including eutrophication, habitat modification and introduction of exogenous HAB organisms). HABs constitute a complex global problem that might increase in severity and frequency, and be expanded in biogeographic range, in our changing planet (GlobalHAB).

Facts and figures

Harmful algal blooms occur when colonies of algae grow out of control and produce toxic or harmful effects on people, fish, shellfish, marine mammals and birds. HABs occur naturally, but human activities that disturb ecosystems seem to play a role in their more frequent occurrence and intensity. Increased nutrient loadings and pollution, food web alterations, introduced species, water flow modifications and climate change all play a role. Studies show that many algal species flourish when wind and water currents are favorable. In other cases, HABs may be linked to “overfeeding.” This occurs when nutrients (mainly phosphorus and nitrogen) from sources such as lawns and agriculture flow into bays, rivers, and the sea, and build up at a rate that “overfeeds” the algae that exist normally in the environment. Some HABs appear in the aftermath of natural phenomena like sluggish water circulation, unusually high water temperatures, and extreme weather events like hurricanes, floods, and drought (NOAA).

HABs are natural processes that occur in all aquatic systems and cause worldwide problems with significant economic, socio-cultural, and human health consequences. There is considerable concern that some HABs and/or their associated impacts may be increasing and expanding globally due to a combination of natural and human-driven forcing, including climate change. In the past two decades, improvements in scientific understanding of the complex processes involved in HAB dynamics have contributed to better management of the risks associated with some harmful events (GlobalHAB).

UN-SPIDER Regional Support Offices with hazard-specific expertise

Related content on the Knowledge Portal

  • PRISMA (Hyperspectral Precursor of the Application Mission), mission fully funded by Italian Space Agency (ASI), is an Earth Observation system with innovative, electro-optical instrumentation that combine a hyperspectral sensor with a medium-resolution panchromatic camera. The advantages of this combination are that in addition to the usual capability of observation based on recognising the geometric characteristics of the scene there are hyperspectral sensors which determine the chemical-physical composition of the objects present on the scene. This offers the scientific community and users many applications in the field of environmental monitoring, resource management, crop classification, pollution control and other things.

    read more
    22/03/2019
  • The Sentinels are a fleet of satellites designed specifically to deliver the wealth of data and imagery that are central to the European Commission’s Copernicus programme.
    Sentinel-2 carries an innovative wide swath high-resolution multispectral imager with 13 spectral bands for a new perspective of our land and vegetation. The combination of high resolution, novel spectral capabilities, a swath width of 290 km and frequent revisit times provides unprecedented views of Earth.
    The mission is based on a constellation of two identical satellites in the same orbit, 180° apart for optimal coverage and data delivery. Together they cover all Earth’s land surfaces, large islands, inland and coastal waters every five days at the equator. Sentinel-2B was launched on 7 March 2017.
    As well as monitoring plant growth, Sentinel-2 can be used to map changes in land cover and to monitor the world’s forests. It also provides information on pollution in lakes and…

    read more
    07/03/2017
  • The Sentinels are a fleet of satellites designed specifically to deliver the wealth of data and imagery that are central to the European Commission’s Copernicus programme.
    Sentinel-2 carries an innovative wide swath high-resolution multispectral imager with 13 spectral bands for a new perspective of our land and vegetation. The combination of high resolution, novel spectral capabilities, a swath width of 290 km and frequent revisit times provides unprecedented views of Earth.
    The mission is based on a constellation of two identical satellites in the same orbit, 180° apart for optimal coverage and data delivery. Together they cover all Earth’s land surfaces, large islands, inland and coastal waters every five days at the equator. Sentinel-2A was launched on 23 June 2015.
    As well as monitoring plant growth, Sentinel-2 can be used to map changes in land cover and to monitor the world’s forests. It also provides information on pollution in lakes and coastal waters. Images of…

    read more
    23/06/2015
  • Gaofen-2 is a follow-on mission of the Gaofen-1technology demonstration mission, a series of high-resolution optical Earth observation satellites of CNSA (China National Space Administration), Beijing, China. GF-2 is part of the CHEOS (China High Resolution Earth Observation System) family.
    The mission goal of GF-2 to implement sub-meter level, high geographical accuracy Earth surface imaging, promoting application of CHEOS satellites and its social and economic benefits, meanwhile to make breakthrough in key technologies like fast roll and high stable attitude control, long focal length large f-number, lightweight camera design and long life bus design, enhancing China's civilian imaging satellite abilities and reliability.

    Instrument: PMC-2 (PAN and Multispectral Camera Suite-2)
    - 2 barrel-mounted panchromatic cameras
    - 2 MS (Multispectral) cameras
    - swath width: 23km for each camera / combined swath width: 45.3km

    read more
    19/08/2014
  • SPOT-7 is a high-resolution wide-swath imaging spacecraft built and operated by Airbus Defence and Space taking over the majority of Spot Image after the government support of the SPOT program was terminated. SPOT-6 – launched in 2012 – and SPOT-7 are identical spacecraft, based on the AstroSat-250 satellite bus and use the NAOMI (New AstroSat Optical Modular Instrument) payload to acquire optical imagery to ensure the continuity of SPOT data, building on experience gained through previous missions, particularly SPOT-5 that launched in 2002.
    The SPOT-7 spacecraft is built for a ten-year mission featuring two NAOMI cameras to cover a 60-Kilometer ground swath, 120km using single-pass mosaic imaging. Overall, the satellite can achieve a resolution of two meters in panchromatic and eight meters in multispectral mode covering the visible and near-infrared spectral bands.

    Instrument: 2x…

    read more
    30/06/2014
  • The Proba-V satellite may only be slightly larger than a washing machine, but it is tasked with a full-scale mission. This miniature satellite is designed to map land cover and vegetation growth across the entire globe every two days. Over the last decade 'Proba' has become synonymous with small high-performance satellites, designed around innovation. The two previous satellites in the series were demonstration missions to give promising technologies an early chance to fly in space. They were overseen by ESA’s Directorate of Technical and Quality Management. Although designed as a demonstration mission, the success of the first Proba satellite led to it being operated as an Earth observation Third Party Mission. Proba-1 carries a high-resolution imaging spectrometer. 

    read more
    07/05/2013
  • Gaofen-1 (gao fen = high resolution) is the first of a series of high-resolution optical Earth observation satellites of CNSA (China National Space Administration), Beijing, China. The civilian HDEOS (High-Definition Earth Observation Satellite) program was proposed in 2006, it received government approval and was initiated in 2010. China plans to launch six HDEOS spacecraft between 2013 and 2016. The major users of the observation data will be the Ministry of Land and Resources, Ministry of Environmental Protection, and the Ministry of Agriculture.
    The GF-1 spacecraft was launched on April 26, 2013 on a CZ-2D (Long March -2D) vehicle from the JSLC (Jiuquan Satellite Launch Center) in northwest China.

    Instruments:
    PMC (PAN and Multispectral camera)
    WFI (Wide Field Imager)

    26/04/2013
  • Landsat 8 launched on February 11, 2013, from Vandenberg Air Force Base, California, on an Atlas-V 401 rocket, with the extended payload fairing
 (EPF) from United Launch Alliance, LLC. The Landsat 8 satellite payload consists of two science instruments—the Operational Land Imager (OLI) and the Thermal Infrared Sensor (TIRS). These two sensors provide seasonal coverage of the global landmass at a spatial resolution of 30 meters (visible, NIR, SWIR); 100 meters (thermal); and 15 meters (panchromatic).
    Landsat 8 was developed as a collaboration between NASA and the U.S. Geological Survey (USGS). NASA led the design, construction, launch, and on-orbit calibration phases, during which time the satellite was called the Landsat Data Continuity Mission (LDCM). On May 30, 2013, USGS took over routine operations and the satellite became Landsat 8. USGS leads post-launch calibration activities, satellite operations, data product generation, and data archiving at the Earth…

    read more
    11/02/2013
  • Launched in December 2011, Pleiades is a constellation of two very-high-resolution satellites capable of acquiring imagery of any point on the globe in under 24 hours for civil and military users.
    Pleiades has been observing and mapping Earth’s surface at a resolution of just 70 cm every day since December 2011. Comprising the Pleiades 1A and Pleiades 1B satellites, this space imaging system complements the capabilities of the SPOT satellites, which have a wider field of view than Pleiades but lower spatial resolution. What’s more, as Pleiades 1A and 1B are in the same orbit, together they can image anywhere on Earth in less than 24 hours. Pleiades imagery is used for both civil and military applications, for example to track urban expansion, monitor the planet’s active volcanoes or assist road and railway routing, and to locate adversaries’ military installations for mission planning. Pleiades’ key asset is an extremely sensitive optical…

    read more
    01/12/2012
  • SJ-9 (Shi Jian = Practice) is a technology demonstration formation flight mission of CNSA (China National Space Administration), consisting of two minisatellites of different sizes and capabilities, SJ-9A and SJ-9B. The overall mission concept is to demonstrate the functionality of a range of newly developed formation flying techniques and components and to validate the formation flight GNC (Guidance, Navigation and Control) algorithms and strategies of the system configuration.
    SJ 9A is based on the CAST-2000 bus. It conducts in-orbit experiments for electric propulsion, high-precision- and high-stability control systems, high-efficienent power supply and advanced thermal control technology. The satellite features also instruments for Earth observation and component tests of indigenously developed technology.

    Instruments: High-performance small camera
    - integrated panchromatic and multispectral design
    - swath width: 30km
    -…

    read more
    14/10/2012

Term Parents

UN-SPIDER Regional Support Offices with hazard-specific expertise