Durand, Dominique

Groom, Steve

Johannessen, Ola M.

Lavender, Samantha

Noji, Thomas

Pettersson, L.H.

Regner, Peter

Svendsen, Einar

Søiland, Henrik

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Satellite observations and forecasting can mitigate effects of toxic algae blooms

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Satellite observations and forecasting can mitigate effects of toxic algae bloomsLasse H. Pettersson1, Dominique Durand1, Ola M. Johannessen1, Thomas Noji2, Henrik Søiland2, Einar Svendsen2, Steve Groom3, Samantha Lavender4 and Peter Regner51 Nansen Environmental & Remote Sensing Center, Norway; 2 Institute of Marine Research, Norway; 3 Centre for Coastal  and Marine Sciences - Plymouth Marine Laboratory, UK; 4 Institute of Marine Studies, University of Plymouth, UK 5 European Space Agency, ItalyContact: Lasse.Pettersson@nrsc.no http://www.nrsc.no/Decide-HABINSTITUTE OF MARINE RESEARCHIn Norway, a national harmful algae bloom (HAB)monitoring service operates each year during the main bloomseason from March to October. This ALGEINFO servicepublishes weekly information on a public web-site(http://algeinfo.imr.no) about the algae bloom situation alongthe coast of Norway.During alert HAB situations, an operational co-ordinationcentre is established to perform analysis of the bloom, makedecisions and disseminate information to the authorities, theindustry (fisheries, aquaculture), the public and mass media.It appears that the early warning and prediction capabilityof the current monitoring system are limited due to the smallnumber of offshore measurement stations and the trans-boundary nature of algae bloom.To facilitate successful mitigation actions, an additionalservice based on daily analysis of Earth Observation (EO)data and numerical forecasting have been implemented inorder to overcome the above limitations. The main componentis the provision of daily information on algae blooms at aregional scale, based on the analysis and interpretation ofocean colour EO data. This information is made available toexperts through a web-site at the Nansen Center(www.nrsc.no/Decide-HAB).A main constraint on the system and service is the delay ofaccessibility to the information. An important part of theinformation flow, including EO data reception and processing,data transfer and daily update of the web site,  has beenautomatised in order to ensure the delivery of informationabout the bloom situation within 6 hours after data acquisitionby the satellite.Daily analysis of SeaWiFS-derived productsSimulation of nitrate concentration showing results for a depth of 3 mfor the dates 21 April, 8 May and 16 May 2000Simulation of flagellate carbon biomass showing results for a depth of 3 mfor the dates 21 April, 8 May and 16 May 2000Capability of DeciDe-HAB service• Ability to give early warning about potentially harmfulalgae blooms• Information is directly accessible on a web-site• Information is updated on a daily basis under cloud-free conditions and thus complements the weeklyupdated ALGEINFO service• Better integration of the regional dimension of theHAB events, including open-ocean monitoring• Potential improvement of regional co-operation withneighbouring countries• An archive of 300 SeaWiFS images of bloomconditions during 1998 - 2000• Integration of EO products with numerical forecastingmodelling has the potential to improve the quantitativepredictions of development and decay of identifiedblooms.Results of simulations indicated that as of 8 May the highest concentrations of flagellates (dominated byChattonella sp.) at a depth of 3 m were still located primarily along the coast of Denmark. A high-concentration band extended also from the northern tip of Denmark westward through the Skagerrak.  Theoverall distribution of the HAB corresponded well with satellite observations of distributions for sea-surfacetemperature and chlorophyll. The simulation also indicated that nitrate in surface waters would be rapidlydepleted by the growth of the bloom.  Based on the weather forecast for the area, prediction for HABdevelopment indicated that the bloom would enter a phase of decline by 16 May and would not present animmediate threat to aquaculture installations along the southern coast of Norway.  This forecast wasimmediately communicated to the Fisheries Authorities.The prediction was consistent with SeaWiFS and NOAA-AVHRR image obtained from May 14, and with insitu measurements.The bloom of the flagellate, Chattonella sp., was firstobserved by satellite off the western coast of Denmarkon 18 April 2000, and confirmed two days later by insitu measurements.  The 3D coupled physical-ecosystem model NORWECOM, used to predict thebloom development, was initialized using SeaWiFS-derived chlorophyll pigment concentration from 18 and19 April.SeaWiFS-derived chlorophyllpigment concentration databasecovering March - July 1998March - July 1999March - July 2000NERSCNansen Environmental and Remote Sensing CenterN-5059 Bergen, NorwaySeaWiFS image copyright:  NASA SeaWiFS project / Orbital Imaging Corp.Contribution CM 2000/O:71Contribution CM 2000/O:7Session: O – Sustainable Aquaculture DevelopmentSatellite observations and forecasting can mitigate effectsof toxic algae bloomsLasse H. Pettersson1, Dominique Durand1, Thomas Noji2, Henrik Søiland2, EinarSvendsen2, Steve Groom3, Samantha Lavender4, Peter Regner5 and Ola M. Johannessen11 Nansen Environmental & Remote Sensing Center, Norway; 2 Institute of MarineResearch, Norway; 3 Centre for Coastal  and Marine Sciences - Plymouth MarineLaboratory, UK; 4 Institute of Marine Studies, University of Plymouth, UK; 5 EuropeanSpace Agency, ItalyIn Norway, a national harmful algae bloom (HAB) monitoring service operates eachyear during the main bloom season from March to October. This ALGEINFO servicepublishes weekly information on a public web-site (http://algeinfo.imr.no) about the algaebloom situation along the coast of Norway.  During alert HAB situations, an operationalco-ordination centre is established to perform analysis of the threat, make decisions anddisseminate information to the industry (fisheries, aquaculture), the public and massmedia. It appears that the early warning and prediction capability of the currentmonitoring system are limited due to the small number of offshore measurement stationsand the trans-boundary nature of algae bloom.To facilitate successful mitigation actions, additional services based on dailyanalysis of Earth Observation (EO) data and numerical forecasting have beenimplemented with the financial support of the European Space Agency in order toovercome the above limitations. The main component is the provision of dailyinformation on algae blooms at a regional scale, based on the analysis and interpretationof EO data. This information is made available to experts through a web-site at theNansen Center (www.nrsc.no/Decide-HAB).A main constraint on the system and service is the delay of accessibility to theinformation. An important part of the information flow, including EO data reception andprocessing, data transfer and daily update of the web site,  has been automatised in orderto ensure the delivery of first level information within 6 hours after data acquisition bythe satellite.The bloom of the flagellate, Chattonella sp., was first observed by satellite off thewestern coast of Denmark on about 18 April 2000, and confirmed two days later by insitu measurements.  The 3D coupled physical-ecosystem model NORWECOM, used topredict the bloom development, was initialized using SeaWiFS-derived chlorophyllpigment concentration from 18 and 19 April.Results of simulations indicated that as of 8 May the highest concentrations of flagellates(dominated by Chattonella sp.) at a depth of 3 m were still located primarily along thecoast of Denmark. A high-concentration band extended also from the northern tip ofDenmark westward through the Skagerrak.  The overall distribution of the HABcorresponded well with satellite observations of distributions for sea-surface temperatureContribution CM 2000/O:72and chlorophyll. The simulation also indicated that nitrate in surface waters would berapidly depleted by the growth of the bloom.  Based on the weather forecast for the area,prediction for HAB development indicated that the bloom would enter a phase of declineby 16 May and would not present an immediate threat to aquaculture installations alongthe southern coast of Norway.  This forecast was immediately communicated to theFisheries Authorities.The prediction was confirmed  by SeaWiFS and NOAA-AVHRR image analysis and insitu measurements.The demonstration experiment run between March and July 2000 enabled us todemonstrate the capability of the DeciDe-HAB monitoring service:• Ability to alert authorities about potentially harmful algae bloom• Information is directly accessible on a web-site• Information is updated on a daily basis and thus complements the weekly updatedALGEINFO service• Better integration of the regional dimension of the HAB events is achieved• Potential improvement of regional co-operation with neighbouring countries can beobtained• An archive of 300 SeaWiFS images of bloom conditions is maintained• Integration of EO products with numerical forecasting modelling has the potential toimprove the quantitative predictions of development and decay of blooms.For more information contact:Lasse.Pettersson@nrsc.nohttp://www.nrsc.no/Decide-HAB

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https://imr.brage.unit.no/imr-xmlui/bitstream/11250/106103/1/CM_2000_O_07.pdf

Satellite observations and forecasting can mitigate effects of toxic algae blooms

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