The IOC and IAEA is proud to announce the publication of IOC Manuals & Guides no 59

This manual is intended as an introduction to basic analytical techniques that can be applied when designing a standard sampling protocol for both planktonic and benthic microalgae (and associated environmental conditions) and vectors of biotoxins (shellfish and fish). This standardization of methods will enable more robust data comparisons between countries and will yield improved risk assessments of potentially toxic HABs events.

This Manual is a joint product of the IAEA and the IOC of UNESCO. The IAEA and the IOC express their profound gratitude to the highly committed editors Beatriz Reguera (Spain), Rosalba Alonso (Mexico), Ángel Moreira (Cuba), Silvia Méndez

(Uruguay), who also contributed as authors; to the expert authors that prepared the original manuscript in Spanish and the updated version in English: and to Laura-Victoria Perdomo and Andrés-Leonardo Malagón (Colombia), Jaime Espinoza (El Salvador), and Leonel Carrillo (Guatemala) who revised the first (Spanish) edition; to Patricia Tester (USA) as a new co-author of chapter 3 in this second (English) edition, and to Mireille Chinain (French Polynesia) and Rachel Clausing (IAEA) who contributed with a new chapter 8 for this second edition.

This publication was funded under the US Peaceful Use Initiative within the framework of the International Atomic Energy Agency (IAEA) Technical Cooperation Project RAS7026 and through IOC UNESCO Regular Programme for the Harmful Algal Bloom Programme. The International Atomic Energy Agency is grateful to the Government of the Principality of Monaco for the support provided to its Environment Laboratories.

NEW: Scientific Summary for Policy Makers on Harmful Algal Blooms

New publication on Harmful Algal Blooms for policy makers

© ESA Satellite photo of a phytoplankton bloom near Ireland.

Harmful Algal Blooms (HABs) occur in nearly all aquatic environments and can cause harm to aquatic ecosystems, including plants and animals, and to humans via direct exposure to water-borne toxins or by toxic seafood consumption. The severity and frequency of some types of HABs is increasing. In order to address this worldwide phenomenon, research, monitoring, and management must be closely integrated with policy decisions that affect our global ocean. With this in mind, a new Scientific Summary for Policymakers on Harmful Algal Blooms was launched during the 28th session of the Intergovernmental Oceanographic Commission’s Assembly at UNESCO headquarters on 17 June 2015.


Many natural and anthropogenic factors regulate the occurrence, frequency and impact of algal events, ranging from local eutrophication, changes in climate and increased exploitation of coastal areas. The Summary considers the causes, impacts and mitigation options, including management issues associated with harmful algal events and their impacts on ecosystems and society. This overview of the current scientific understanding of harmful algal blooms and mitigation options will assist non-specialist and decisions makers in planning monitoring and management of harmful algal events to address environmental, socio-economic and health impacts.

It was prepared by the Global Ecology and Oceanography of Harmful Algal Blooms research programme (GEOHAB), a joint project of the Scientific Committee on Oceanic Research (SCOR) and the Intergovernmental Oceanographic Commission (IOC) of UNESCO, and benefited from the contributions of experts all over the world.

the Scientific Summary is freely availableonline(pdf). For printed copies, please contact:

Related links:

From the scientic literature:

Harmful algal blooms and climate change: Learning from the past and present to forecast the future. Mark L. Wells a,*, Vera L. Trainer b, Theodore J. Smayda c, Bengt S.O. Karlson d,Charles G. Trick e, Raphael M. Kudela f, Akira Ishikawa g, Stewart Bernard h, Angela Wulff i,
Donald M. Anderson j, William P. Cochlan k. Harmful Algae 49 (2015) 68–93.

Climate change pressures will influence marine planktonic systems globally, and it is conceivable that
harmful algal blooms may increase in frequency and severity. These pressures will be manifest as
alterations in temperature, stratification, light, ocean acidification, precipitation-induced nutrient
inputs, and grazing, but absence of fundamental knowledge of the mechanisms driving harmful algal
blooms frustrates most hope of forecasting their future prevalence. Summarized here is the consensus of
a recent workshop held to address what currently is known and not known about the environmental
conditions that favor initiation and maintenance of harmful algal blooms. There is expectation that
harmful algal bloom (HAB) geographical domains should expand in some cases, as will seasonal
windows of opportunity for harmful algal blooms at higher latitudes. Nonetheless there is only basic
information to speculate upon which regions or habitats HAB species may be the most resilient or
susceptible. Moreover, current research strategies are not well suited to inform these fundamental
linkages. There is a critical absence of tenable hypotheses for how climate pressures mechanistically
affect HAB species, and the lack of uniform experimental protocols limits the quantitative crossinvestigation
comparisons essential to advancement. A HAB ‘‘best practices’’ manual would help foster
more uniform research strategies and protocols, and selection of a small target list of model HAB species
or isolates for study would greatly promote the accumulation of knowledge. Despite the need to focus on
keystone species, more studies need to address strain variability within species, their responses under
multifactorial conditions, and the retrospective analyses of long-term plankton and cyst core data;
research topics that are departures from the norm. Examples of some fundamental unknowns include
how larger and more frequent extreme weather events may break down natural biogeographic barriers,
how stratification may enhance or diminish HAB events, how trace nutrients (metals, vitamins)
influence cell toxicity, and how grazing pressures may leverage, or mitigate HAB development. There is
an absence of high quality time-series data in most regions currently experiencing HAB outbreaks, and
little if any data from regions expected to develop HAB events in the future. A subset of observer sites is
recommended to help develop stronger linkages among global, national, and regional climate change
* Corresponding author. Tel.: +1 207 581 4322. E-mail addresses: This email address is being protected from spambots. You need JavaScript enabled to view it. (M.L. Wells), This email address is being protected from spambots. You need JavaScript enabled to view it. (V.L. Trainer), This email address is being protected from spambots. You need JavaScript enabled to view it. (T.J. Smayda), This email address is being protected from spambots. You need JavaScript enabled to view it. (Bengt S.O. Karlson), This email address is being protected from spambots. You need JavaScript enabled to view it. (C.G. Trick), This email address is being protected from spambots. You need JavaScript enabled to view it. (R.M. Kudela), This email address is being protected from spambots. You need JavaScript enabled to view it. (A. Ishikawa), This email address is being protected from spambots. You need JavaScript enabled to view it. (S. Bernard), This email address is being protected from spambots. You need JavaScript enabled to view it. (A. Wulff), This email address is being protected from spambots. You need JavaScript enabled to view it. (D.M. Anderson), This email address is being protected from spambots. You need JavaScript enabled to view it. (W.P. Cochlan).

REVIEW: OCEAN CLIMATE CHANGE, PHYTOPLANKTON COMMUNITY RESPONSES, AND HARMFUL ALGAL BLOOMS: A FORMIDABLE PREDICTIVE CHALLENGE, by Gustaaf M. Hallegraeff, Institute of Marine and Antarctic Studies, and School of Plant Science, University of Tasmania, Private Bag 55, Hobart,Tasmania 7001, Australia.  J. Phycol. 46, 220–235 (2010), 2010 Phycological Society of America, DOI: 10.1111/j.1529-8817.2010.00815.x

Prediction of the impact of global climate change on marine HABs is fraught with difficulties. However, we can learn important lessons from the fossil record of dinoflagellate cysts; long-term monitoring programs, such as the Continuous Plankton Recorder surveys; and short-term phytoplankton community responses to El Nino Southern Oscillation (ENSO) and North Atlantic Oscillation (NAO) episodes.Increasing temperature, enhanced surface stratification, alteration of ocean currents, intensification or weakening of local nutrient upwelling, stimulation of photosynthesis by elevated CO2, reduced calcification through ocean acidification (‘‘the other CO2 problem’’), and heavy precipitation and storm events causing changes in land runoff and micronutrient availability may all produce contradictory species- or even strain-specific responses. Complex factor interactions exist, and simulated ecophysiological laboratory experiments rarely allow for sufficient acclimation and rarely take into account physiological plasticity and genetic strain diversity. We can expect: (i) range expansion of warm-water species at the expense of cold-water species, which are driven poleward; (ii) speciesspecific changes in the abundance and seasonal window of growth of HAB taxa; (iii) earlier timing of peak production of some phytoplankton; and (iv) secondary effects for marine food webs, notably when individual zooplankton and fish grazers are differentially impacted (‘‘match-mismatch’’) by climate change. Some species of harmful algae (e.g., toxic dinoflagellates benefitting from land runoff and ⁄ or water column stratification, tropical benthic dinoflagellates responding to increased water temperatures and coral reef disturbance) may become more successful,while others may diminish in areas currently impacted. Our limited understanding of marine ecosystem responses to multifactorial physicochemical climate drivers as well as our poor knowledge of the potential of marine microalgae to adapt genetically and phenotypically to the unprecedented pace of current climate change are emphasized. The greatest problems for human society will be caused by being unprepared for significant range expansions or the increase of algal biotoxin problems in currently

poorly monitored areas, thus calling for increased vigilance in seafood-biotoxin and HAB monitoring programs. Changes in phytoplankton communities provide a sensitive early warning for climate-driven perturbations to marine ecosystems.



The GEOHAB Scientific Steering Committee has developed an Advisory Bulletin to provide sound scientific and technical advice to decision-makers in relation to proposals to add urea to the sea in order to stimulate algal blooms and sequester carbon for commercial purposes.

Download at IOC and SCOR communicated the Advisory Bulletin to the IMO London Convention Scientific Group on Ocean Fertilization. See also a 57-author view point paper in the Marine Pollution Bulletin: Gilbert et al., 2008. Ocean urea fertilization for carbon credits poses high ecological risks. Marine Pollution Bulletin, doi·:10.1016/j.marpolbul.2008.03.010).


1. A new manual on microscopic and molecular methods for quantitative phytoplankton analysis is available from the IOC in cooperation with ICES. The manual includes illustrated step by step instructions on how to carry out the methods. The manual can be downloaded as a pdf-file here.

Intergovernmental Oceanographic Commission of ©UNESCO. 2010. Karlson, B., Cusack, C. and Bresnan, E. (editors). Microscopic and molecular methods for quantitative phytoplankton analysis. Paris, UNESCO. (IOC Manuals and Guides, no. 55.) (IOC/2010/MG/55), 110 pages. (English only)

2. Real-time Coastal Observing Systems for Marine Ecosystem Dynamics and Harmful Algal Blooms: Theory, Instrumentation and Modeling. Edited by Marcel Babin, Collin Roesler and John Cullen. Download order form here

A leading system to provide data and information on toxic algae in the world oceans

An international Task Team set up by the IOC Intergovernmental Panel on Harmful Algal Blooms (IPHAB) and the IOC International Ocean Data Exchange (IODE), is working to develop a Harmful Algal Information System (HAIS). HAIS is envisaged to become the leading system to provide data and information on toxic algae in the world oceans based upon data received from national monitoring operations and scientific expertise provided by national experts.

Read more about HAIS here.

Hosted by UNESCO/IOC Project Office for IODE Oostende, Belgium