Progress in Understanding Harmful Algal Blooms: Paradigm Shifts and New Technologies for Research, Monitoring, and Management

Abstract

The public health, tourism, fisheries and ecosystem impacts from harmful algal blooms (HABs) have all increased over the last few decades. This has led to heightened scientific and regulatory attention, and the development of many new technologies and approaches for research and management. This in turn, is leading to significant paradigm shifts with regard to, e.g., our interpretation of the phytoplankton species concept (strain variation), the dogma of their apparent cosmopolitanism, the role of bacteria and zooplankton grazing in HABs, and our approaches to investigating the ecological and genetic basis for the production of toxins and allelochemicals. Increasingly, eutrophication and climate change are viewed and managed as multifactorial environmental stressors that will further challenge managers of coastal resources and those responsible for protecting human health. Here we review HAB science with an eye towards new concepts and approaches, emphasizing, where possible, the unexpected yet promising new directions that research has taken in this diverse field.

Potentially harmful cyanobacteria in oyster banks of Términos lagoon, southeastern Gulf of Mexico

“…This feature is reinforced where salinity values are low and the relative proportion of cyanobacteria in biomass can be used as an indicator of eutrophication, as shown in Figure 3, where the highest percentages with respect to abundances were found at stations S1, S3 and S4, classified as brackish (salinity ≈14). This indicator has been reinforced because of the increase in terrestrial temperature, leading to an increase in cyanobacterial proliferations in continental ecosystems (Jöhnk et al, 2008), closely associated with eutrophication (Anderson et al, 2012). In general, cyanobacteria exhibit a cosmopolitan distribution, inhabiting hypersaline, marine and freshwater environments, and therefore have a wider range of habitats than phototrophic eukaryotes (Mur et al, 1999;Graham and Wilcox, 2000;Whitton and Potts, 2002;Ludeña-Hinojosa, 2007).…”

Green and golden seaweed tides on the rise

“…In most cases, the harmful effects are caused by phytoplankton species that render seafood toxic, result in the mass death of marine animals or affect aquaculture operations. High-biomass phytoplankton blooms can also be a nuisance on beaches by discolouring the water (red and brown tides) or forming scums and foams 43 . Their biomass is low compared with green tides, but they can also cause anoxic events, albeit in deeper water.…”

Stock enhancement or sea ranching? Insights from monitoring the genetic diversity, relatedness and effective population size in a seeded great scallop population (Pecten maximus)

“…Although the first goal of the supportive breeding program is to enhance the local recruitment and improve the productivity of the scallop population in the Bay of Brest, the stock is far from having recovered to its historical levels (Alban and Boncoeur, 2008). Various factors may strongly limit the demographic growth of the local population, such as trophic competition with non-native invasive species like Crepidula fornicata (Thouzeau et al, 2000) or Crassostrea gigas (Lejart and Hily, 2011), increased predation, or emerging environmental pressures (eutrophication, toxic algal bloom; Anderson et al, 2002Anderson et al, , 2012. Genetic monitoring of the population in the Bay of Brest should be continued over a longer period of time and extended to other seeded scallop populations.…”