In Canada, reports of marine harmful algal blooms (HABs) have increased over the past few decades. HABs are caused by the growth of certain phytoplankton that produce phycotoxins or otherwise cause harm. Phycotoxins are problematic to human health, and their cumulative effects are stressors to marine ecosystems by causing the mortality of marine fish, birds and mammals, including species designated at risk. Paralytic Shellfish Poisoning (caused by saxitoxin group toxins produced by Alexandrium spp.) has been problematic for years on both the east and west Canadian coasts. Amnesic Shellfish Poisoning (caused by domoic acid produced by Pseudo-nitzschia spp.) was identified for the first time worldwide following consumption of blue mussels from eastern Canada in 1987. Domoic acid has since also been found on the west coast. Diarrhetic Shellfish Poisoning (caused by okadaic acid group toxins produced by Dinophysis spp. and Prorocentrum spp.) was first recognized as a hazard in eastern Canadian waters in 1990, and these phycotoxins have since been found on both the east and west Canadian coasts. Other phycotoxins that may cause harm to human health in Canada include pectenotoxins, yessotoxins, azaspiracids, and cyclic imine group toxins (spirolide toxins, pinnatoxins, and gymnodimines). Multiple harmful algal species have been associated with fish-killing blooms on both east and west Canadian coasts. The range of exotic toxic/harmful algae is expanding in Canadian waters due in part to introductions from ships’ ballast water and climate change. The detection of domoic acid and the discovery of several toxigenic diatoms and dinoflagellates in the Canadian Arctic is of increasing concern because of the limited knowledge of HABs in this region. Canada’s experience in dealing with toxic events resulted in research and monitoring programs designed to understand HABs and to assist the fishing and aquaculture industries. In spite of decreases in research and phytoplankton monitoring efforts, consumers of molluscan shellfish are still protected by phycotoxin monitoring, which is conducted by the Canadian Food Inspection Agency. Novel phycotoxins and toxic algae will continue to be discovered. Continued vigilance and the maintenance of an effective capacity to manage developing problems via strategic research programs is essential. This document reviews Canadian marine HABs and phycotoxins up to late 2018, and provides a foundation for any future research in this area.
In the Gulf of Mexico, especially along the southwest Florida coast, blooms of the dinoflagellate Karenia brevis are a coastal natural hazard. The organism produces a potent class of toxins, known as brevetoxins, which are released following cell lysis into ocean or estuarine waters or, upon aerosolization, into the atmosphere. When exposed to sufficient levels of brevetoxins, humans may suffer from respiratory, gastrointestinal, or neurological illnesses. The hazard has been exacerbated by the geometric growth of human populations, including both residents and tourists, along Florida’s southwest coast. Impacts to marine organisms or ecosystems also may occur, such as fish kills or deaths of protected mammals, turtles, or birds. Since the occurrence of a severe Karenia brevis bloom off the southwest Florida coast three-quarters of a century ago, there has been an ongoing debate about the best way for humans to mitigate the impacts of this hazard. Because of the importance of tourism to coastal Florida, there are incentives for businesses and governments alike to obfuscate descriptions of these blooms, leading to the social amplification of risk. We argue that policies to improve the public’s ability to understand the physical attributes of blooms, specifically risk communication policies, are to be preferred over physical, chemical, or biological controls. In particular, we argue that responses to this type of hazard must emphasize maintaining the continuity of programs of scientific research, environmental monitoring, public education, and notification. We propose a common-sense approach to risk communication, comprising a simplification of the public provision of existing sources of information to be made available on a mobile website.
The human dimensions of harmful algal blooms (HABs) are becoming increasingly apparent as they grow in frequency and magnitude in some regions of the world under changing ocean conditions. One such region is the U.S. West Coast, where HABs of toxigenic species of Pseudo-nitzschia have been found to coincide with or closely follow periods of warming. In 2015, the region experienced a massive HAB of Pseudo-nitzschia that was associated with the 2014-16 Northeast Pacific marine heatwave. The HAB event delayed the opening of the lucrative commercial Dungeness crab fishery for up to 5 months and closed the popular recreational razor clam fishery, resulting in fishery failures and disaster declarations and causing significant sociocultural and economic impacts to coastal communities. Here, management actions are examined that were taken by federal and state government agencies and responses of coastal residents to this extreme HAB event using a disaster risk management framework consisting of four phases: 1) prediction and early warning, 2) event response, 3) recovery and reconstruction, and 4) mitigation and prevention. Clear differences in management actions at the state level were evident in California, Oregon, and Washington during every phase, producing vastly different perceptions of management by coastal residents. A history of trusted relationships and coordination among agencies and with the fishing industry in Washington State was associated with more transparent and accepted management responses. The examination found that additional education, outreach, and trust-building exercises would provide benefits to communities affected by extreme HAB events. Our findings contribute to an understanding of climate change adaptation in coastal communities dependent on fishery resources.
The “blob” of anomalously warm surface water that persisted in the North Pacific Ocean from 2013 to 2016 resulted in a massive harmful algal bloom (HAB) of Pseudo-nitzschia along the entire United States West Coast. The bloom produced record-breaking concentrations of domoic acid, a marine neurotoxin, that contaminated seafood and necessitated fisheries harvest closures beginning in May 2015. The subsequent closures were unprecedented in length and geographic extent, generating an economic shock for fishing communities. We sought to identify effective adaptive actions used in fishery-dependent communities in response to this event. Using survey data collected across 16 fishing communities following the 2015 HAB event, we empirically identified factors affecting an individual’s: (1) absolute magnitude of income loss, (2) likelihood of income loss recovery, and (3) severity of emotional stress. Our findings indicate that individuals who suffered greater absolute income losses were exposed to longer fisheries closures, more dependent on shellfish as a source of income, and employed in the fishing industry. Income diversification was an effective strategy for reducing and/or recovering HAB related income losses. Advertising was also found to be an effective income recovery strategy, but for fishers it was associated with increased emotional stress. If increasing the adaptive capacity of fishery-dependent coastal communities to HAB events is a policy goal, then costs to adaptive action such as emotional stress, limited access to alternate fisheries, new fishing gear, a lack of alternate job skills or access to job networks, and a lack of advertising know-how will need to be addressed.
Plastic debris becomes currently a ubiquitous environmental pollutant and is susceptible to contamination by many other pollutants, including aqueous metals and organic matter. This review summarizes the effects of environmental factors on the properties and sorption behavior of microplastics, presents a further discussion on the fate of microplastics adsorption on contaminants, and critically discusses the mechanism of sorption behaviors between micro/nanoplastics and normal contaminants. Previous references indicated that the hydrophobicity and particle sizes of microplastics were the dominant influence factors for virgin plastic debris adsorption, whereas for aged microplastics, hydrogen bonding, hydrophilicity and increasing specific surface ratio affected the adsorption behavior. The effects of pH and salinity always influence the sorption conditions by changing the charge state of microplastics and contaminants and causing competing adsorption. In addition, the existence of microplastics affects biotoxicity, increases the dissolved organic matter in the environment, and influences carbon cycling. The knowledge is fundamental to the assessment of potential risks posed by microplastics to organisms from human beings to the entire environment.
Harmful algae can cause death in fish, shellfish, marine mammals, and humans, via their toxins or from effects associated with their sheer quantity. There are many species, which cause a variety of problems around north-west Europe, and the frequency and distribution of algal blooms have altered in the recent past. Species distribution modelling was used to understand how harmful algal species may respond in the future to climate change, by considering environmental preferences and how these may shift. Most distribution studies to date use low resolution global model outputs. In this study, high resolution, downscaled shelf seas climate projections for the north-west European shelf were nested within lower resolution global projections, to understand how the distribution of harmful algae may change by the mid to end of century. Projections suggest that the habitat of most species (defined by temperature, salinity, depth, and stratification) will shift north this century, with suitability increasing in the central and northern North Sea. An increase in occurrence here might lead to more frequent detrimental blooms if wind, irradiance and nutrient levels are also suitable. Prioritizing monitoring of species in these susceptible areas could help in establishing early-warning systems for aquaculture and health protection schemes.
Harmful algal blooms (HABs) constitute a worldwide problem, affecting aquatic ecosystems, public health and local economies. Supported by the International Atomic Energy Agency since 2009, Latin America and the Caribbean (LAC) countries, including Brazil, Chile, Colombia, Costa Rica, Cuba, Dominican Republic, El Salvador, Guatemala, Haiti, Mexico, Nicaragua, Panama, Uruguay and Venezuela, have integrated a regional network for early warning of HABs and biotoxins in seafood. Technical capacities have been developed at regional level to identify toxic species, evaluate biota toxicity, and to perform retrospective analysis of HAB occurrence. This network involves 58% of the coastal LAC countries, two regional reference centers (in El Salvador and Cuba), 14 well equipped institutions, and 177 professionals trained to contribute to the operation of HAB and biotoxin monitoring programs. All countries from the network have reported planktonic and benthic toxic species, and in selected cases, associated with toxin in biota. Dinocyst abundance analysis in 210Pb-dated sediment cores have shown that some harmful species have been present in the region for at least 100 years ago, and that both coastal water pollution and climate change are important drivers for HAB occurrence. Efforts must be made to enrich the data base records on HAB events occurred in LAC, better understand key environmental variables that control HABs and expand coverage of HAB monitoring to all coastal countries in LAC to promote sustainable development of the region.
In the spring of 2015, a massive harmful algal bloom (HAB) of the toxin-producing diatom Pseudo-nitzschia occurred on the U.S. West Coast, resulting in the largest recorded outbreak of the toxin domoic acid and causing fisheries closures. Closures extended into 2016 and generated an economic shock for coastal fishing communities. This study examines the economic and sociocultural impacts of the Dungeness crab and razor clamfisheries closures on two fishing-dependent communities. Semi-structured interviews were conducted with 36 community members from two communities impacted by the event – Crescent City, California and Long Beach, Washington. Interviewees included those involved in the fishing, hospitality, and retail industries, local government officials, recreational harvesters, and others. Interviews probed aspects of resilience in economic, social, institutional, and physical domains, based on the contention that community resilience will influence the communities’ ability to withstand HAB events. Dimensions of vulnerability were also explored, encompassing sensitivity of the communities to HAB events and their adaptive capacity. Common themes that emerged from the interview responses indicate that economic hardships extended beyond fishing-related operations and permeated through other sectors, particularly the hospitality industry. Significant barriers to accessing financial and employment assistance during extended fisheries closures were identified, particularly for fishers. Long-held traditions surrounding crab and shellfish harvest and consumption were disrupted, threatening the cultural identities of the affected communities. Community members expressed a desire for clearer, more thorough, and more rapid dissemination of information regarding the management of fisheries closures and the health risks associated with HAB toxins. The likelihood of intensifying HABs under climate change heightens the need for actions to increase the resilience of fishing communities to the economic and sociocultural impacts caused by HAB-related fisheries closures.
Harmful algal blooms (HABs) have been the subject of many reports released by Mexican Federal Authorities along the Mexican Coast of the Gulf of Mexico Large Marine Ecosystem (MC-GoM-LME), but extensive research that delves deeply into this issue is lacking. Although Karenia brevis blooms have appeared in all Mexican states (except Quintana Roo) and blooms of Cladophora spp., Chattonella marina, Chattonella subsalsa, Glenodinium pseudostigmosum and Chaetoceros holsaticus are fairly new to the MC-GoM-LME, their spatial and temporal variations are largely unknown. It appears that anthropogenic nutrient over-enrichment is the main driver of eutrophication along the MC-GoM-LME. Trophic conditions based on physicochemical parameters, phytoplankton and submerged aquatic vegetation along the northern coast of Yucatan show the influence of Gulf of Mexico LME and Caribbean Sea LME waters, seasonal upwelling and polluted inputs from submarine groundwater discharges. Meso-eutrophic and oligo-mesotrophic conditions on the coast are associated with human activities such as domestic sewage discharges from septic tanks, harbor effluents and brackish waters from artificial inlets. Coastal lagoons in Veracruz have been impacted by urbanization expansion leading to wastewater discharges, fertilizer runoff and changes in land use. Overall, trophic conditions in Veracruz have improved relative to historic trophic index values. At least for the Yucatan State and the Quintana Roo State, there are sites that appear to link the occurrence of HABs and anthropogenic eutrophication. Additional research over inshore, estuarine, coastal and offshore environments requires future monitoring efforts and collaboration with the international community (especially the U.S.).
Sustainable and effective water management plans must have a reliable risk assessment strategies for harmful cyanobacterial blooms (HABs) that would enable timely decisions to be made, thus avoiding the trespassing of ecological thresholds, leading to the collapse of ecosystem structure and function. Such strategies are usually based on cyanobacterial biomass and/or on the monitoring of known toxins, which may, however, in many cases, under- or over-represent the actual toxicity of the HAB. Therefore, in this study, by the application of growth-inhibition assays using different bacteria, algae, zooplankton and fish species, we assessed the toxicological potential of two cyanobacterial blooms that differed in total cyanobacterial biomass, species composition and cyanopeptide profiles. We demonstrated that neither cyanobacterial community composition nor its relative abundance, nor indeed concentrations of known toxins reflected the potential risk of HAB based on growth-inhibition assays. We discuss our findings in the context of food-web dynamics and ecosystem management, and suggest that toxicological tests should constitute a key element in the routine monitoring of water bodies so as to prevent under-/over-estimation of potential HAB risk for both ecosystem and public health.