Introduction

Table 1.  Examples of toxic microalgae and pthological effects on people and marine organisms.

  The global distribution of harmful algal events in 1999 compared to the 1970's.

             In response to the need to develop the capacity for rapid detection and timely prediction of HAB events, a workshop was held in Pensacola Beach, Florida, USA from 27 November to 1 December, 2000 under the auspices of the U.S. GOOS programme and the National Association of Marine Laboratories.  The purpose of the workshop was to bring data providers (scientists) together with data users (government agencies) to develop plans for the design and implementation of a regional observing system (HABSOS) that will provide the data and information needed for rapid detection and useful predictions of harmful algal blooms and their effects on marine resources and coastal communities in the Gulf of Mexico.  The full report from this workshop may be found at the following URL:  http://www.hpl.umces.edu/projects/HABSOS.pdf

Users

            The primary issues of concern are (1) protecting public health and water quality (paralytic shellfish poisoning, diarrhetic shellfish poisoning, amnesic shellfish poisoning, neurotoxic shellfish poisoning, and respiratory irritation and skin lesions in swimmers and beach goers), (2) effects on aquaculture production (e.g., shellfish bed closures, mass mortalities, contamination), (3) economic impacts (minimize or prevent declines in revenues from fisheries, aquaculture, tourism; decreases in property value), and (4) the dissemination of useful information to the public.  Thus, the primary users of the initial observing system will be government agencies responsible for living marine resources, water quality and public health; fish farmers (mariculture); the tourist industry; and the residents of coastal communities.  Additional users include local businesses, teachers and the news media. 

User Requirements

            The primary user requirements are (1) protecting public health, (2) protecting living marine resources (controlling and mitigating the economic effects of harmful algae on wild fisheries, aquaculture, tourism, property values), (3) dissemination of useful information to the public.  Managers need information, not data.  The following data-products are high priorities

(1) early alerts (location, magnitude, species) that an event is in progress;

(2) timely forecasts of the trajectory of the event in time and space (with probability zones); and

(3) predictions of where and when an event is likely to occur (advance notice of the probability an event will occur).

The HABSOS Pilot Project

            There are approximately 5000 species of microalgae in the world.  Of these, about 100 are toxic and, of these, Krenia brevis (formerly called Gymnodinium breve) is by far the most prevalent in the Gulf of Mexico.  K. brevis causes neurotoxic shellfish poisoning and blooms (“red tides”) increase public health risks from exposure to toxins in aerosols and sea food, cause shellfish bed closures, and impact coastal tourism.  Because it is relatively easy to detect, blooms frequently, and has a regional impact,  K. brevis was selected as the target organism for a pilot observing system

            The immediate priority is to establish a data communications and management system that will provide more timely access to data (from in situ measurements, autonomous in situ sensing and remote sensing) and information (as close to real-time as possible) on K. brevis blooms events and associated environmental conditions.  This will not only reduce the lag time between the occurrence of an event and its detection, it will be invaluable in guiding the development of research programs such as GEOHAB that will provide the technologies and scientific information required for more rapid detection and prediction of HAB events (see http://ioc.unesco.org/hab).

            Once the initial data communications and management infrastructure has been established for the Gulf, improving the sensor and measurement end of the system will become a priority.  The initial observing subsystem will have a nested design with higher resolution measurements organized around “hot spots” or epicenters of HAB events set in the context of a coarser framework of regional measurements that are made regularly and routinely throughout the northern Gulf.   The minimum set of common measurements that should be incorporated into the regional framework of HABSOS are as follows:

(1) Real-time wind fields (updated 3-4 times/day ) and freshwater fluxes (rainfall, rivers, ground water) and related inputs of sediments and nutrients (daily rates updated weekly); and

(2) Surface currents and waves, sea surface temperature and chlorophyll distributions updated daily; vertical profiles (with measurement at surface, pycnocline, near bottom as a minimum) of temperature, salinity, dissolved oxygen, inorganic nutrients (N, P, Si), chlorophyll, colored dissolved organic matter, and cell densities of K. brevis updated at weekly (small number of stations) to monthly intervals (more stations).

            Detection of time-dependent changes in 3 dimensions will rely on a mix of platforms and methods including (1) discrete in situ sampling followed by laboratory measurements (results available within 48 hours of sampling); (2) autonomous in situ sensing with real-time data telemetry; and (3) remote sensing with real-time or near-time data telemetry.  In situ measurements (1 and 2) will be made from docks, small boats, ships, fixed platforms, moorings, drifters, gliders, remotely operated vehicles and autonomous under water vehicles.  Remote sensing will be made from space (e.g., SeaWiFS), from aircraft (e.g., hyperspectral imagery), or from land (e.g., high frequency radar).  Coastal observatories for in situ and remote sensing will become important components of the observing system as the technologies for these platforms and associated sensors develop.

            Although undersampling remains a problem, data on sea surface winds, sea surface temperature, and surface currents and waves and nowcasts of forecasts of weather and marine conditions (surface waves and currents, sea level) are available in near real time now via the world wide web (   Existing observing systems will be enhanced and supplemented to improve temporal and spatial resolution; to make physical, chemical and biological measurements synoptically in time and space; and to achieve real time or near-real time data transmission.  For sample-based measurements such as K. brevis cell counts, the initial goal is a 48 hr turn around time.

            Additional infrastructure will initially include remote sensing to obtain synoptic spatial images of sea surface chlorophyll concentration (SeaWiFS); in situ sensing of temperature, salinity and chlorophyll (in vivo fluorescence); and in situ measurements of temperature, salinity, dissolved oxygen, inorganic nutrients (N, P, Si), chlorophyll, colored dissolved organic matter, and G. breve cell density.  In addition to the measurement program, a high priority will be placed on developing methods to integrate data from remote and in situ sensing and measurements to obtain 4-dimensional visualizations of HAB events and associated environmental variability in a more timely fashion.

Irish Coastal Waters 

            As reported on by representatives from the Irish Marine Institute (IMI) at the HABSOS workshop, a similar effort is underway in Ireland where interest in harmful algae events (HAEs) in Irish coastal waters has dramatically increased in recent years.  The IMI’s Biotoxin Unit is currently in the process of restructuring its phytoplankton monitoring capability to help predict, manage and minimize the impacts of marine biotoxins and potentially harmful algal species on public health and the aquaculture industry.  This programme and HABSOS will benefit from the ongoing exchange of information that was initiated at the workshop.

            Biotoxins, which have the potential to cause diarrhetic, paralytic, amnesic and azaspiracid shellfish poisoning (DSP, PSP, ASP and AZP, respectively), have been detected in shellfish in Ireland.  The toxic phytoplankton species of concern in Irish waters are Dinophysis spp. (DSP), Alexandrium spp. (PSP), and Pseudo-nitzschia spp. (ASP).  The marine source of AZP has yet to be confirmed.  Estimated losses due to biotoxin closures have cost the Irish shellfish industry $4 million in 2000.  In addition, harmful algal events have been linked to the mortality of commercial shellfish stocks and indigenous benthic invertebrates.  The most recent example of this type of impact occurred in Bantry Bay (southwest Ireland) during summer 2000 when an abalone shellfishery was decimated following the appearance of a large bloom of the dinoflagellate Gyrodinium aureolum in the region.    

            The immediate objectives of the IMI programme are to (1) advise the aquaculture industry on early detection and mapping of harmful algal species; (2) develop and update the data base on HAEs in Irish waters; (3) develop physical circulation models and simulation of historic HAEs using passive particle tracking models; and (4) evaluate the use of SeaWiFS, AVHRR and SAR remotes sensing data in the detection and mapping of HAEs and physical features relevant to those events (i.e., fronts, upwelling zones).  A high priority is early detection and mapping of HAEs and the rapid communication of this information to the aquaculture industry, the Food Safety Authority and public health officials.  Toward this aim, the Marine Institute’s new monitoring programme will use microscopic techniques to detect the presence of potentially harmful algal species in aquaculture production areas.  Between 60-80 samples will be analyzed on a weekly year-roung basis (approx. 3,000 pa).  Results, which will include information on abundance of potentially harmful algal species, dominant phytoplankton species and a generic comment on species trends, will be made available by telephone, fax, e-mail and the world wide web within 48 hours of collection.  To investigate the relationship between phytoplankton species and environmental factors, the following parameters are to be recorded by remote sensors at a subset of sampling sites: temperature, salinity, nutrients (nitrate, ammonium, phosphate, and silicate), and wind velocity.

            Access to accurate, pertinent and quality assured data and information regarding HAEs in Irish waters is essential in assessing cause, and in developing management and mitigation procedures to deal with these events.  The database will provide support for research programmes investigating the interactions between HAE occurrence and environmental factors and form the basis for future modeling efforts.  The database will contain the following data sets relevant to HAEs: