Population dynamics of potentially harmful algal blooms in Bizerte Lagoon, Tunisia

Cyanobacteria in the genus Microcystis are dominant components of many harmful algal blooms worldwide. Their pelagic–benthic life cycle helps them survive periods of adverse conditions and contributes greatly to their ecological success. Many studies on Microcystis overwintering have focused on benthic colonies and suggest that sediment serves as the major inoculum for subsequent summer blooms. However, the contemporaneous overwintering pelagic population may be important as well but is understudied. In this study, we investigated near-surface and near-bottom pelagic population dynamics of both microcystin-producing Microcystis and total Microcystis over six weeks in winter at Dog Lake (South Frontenac, ON, Canada). We quantified relative Microcystis concentrations using real-time PCR. Our results showed that the spatiotemporal distribution of overwintering pelagic Microcystis was depth dependent. The abundance of near-bottom pelagic Microcystis declined with increased depth with no influence of depth on near-surface Microcystis abundance. In the shallow region of the lake (<10 m), most pelagic Microcystis was found near the lake bottom (>90%). However, the proportion of near-surface Microcystis rose sharply to over 60% as the depth increased to approximately 18 m. The depth-dependent distribution pattern was found to be similar in both microcystin-producing Microcystis and total Microcystis. Our results suggest the top of the water column may be a more significant contributor of Microcystis recruitment inoculum than previously thought and merits more attention in early CHAB characterization and remediation.

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Harmful algal blooms (HABs) associated with phycotoxins in shellfish: What can be learned from five years of monitoring in Bizerte Lagoon (Southern Mediterranean Sea)?

Ecological Engineering ◽

10.1016/j.ecoleng.2014.03.028 ◽

2014 ◽

Vol 67 ◽

pp. 39-47 ◽

Cited By ~ 32

Author(s):

Souad Turki ◽

Amel Dhib ◽

Mouna Fertouna-Bellakhal ◽

Victor Frossard ◽

Noura Balti ◽

...

Keyword(s):

Mediterranean Sea ◽

Harmful Algal Blooms ◽

Algal Blooms ◽

Bizerte Lagoon ◽

Southern Mediterranean

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Physical flow effects can dictate plankton population dynamics

Journal of The Royal Society Interface ◽

10.1098/rsif.2019.0247 ◽

2019 ◽

Vol 16 (157) ◽

pp. 20190247 ◽

Cited By ~ 3

Author(s):

J. R. Woodward ◽

J. W. Pitchford ◽

M. A. Bees

Keyword(s):

Population Dynamics ◽

Harmful Algal Blooms ◽

Algal Blooms ◽

Large Scale ◽

Temporal Dynamics ◽

Mean Field ◽

Economic Consequences ◽

Mean Flow ◽

Inertia Effects ◽

Physical Forcing

Oceanic flows do not necessarily mix planktonic species. Differences in individual organisms’ physical and hydrodynamic properties can cause changes in drift normal to the mean flow, leading to segregation between species. This physically driven heterogeneity may have important consequences at the scale of population dynamics. Here, we describe how one form of physical forcing, circulating flows with different inertia effects between phytoplankton and zooplankton, can dramatically alter excitable plankton bloom dynamics. This may impact our understanding of the initiation and development of harmful algal blooms (HABs), which have significant negative ecological and socio-economic consequences. We study this system in detail, providing spatio-temporal dynamics for particular scenarios and summarizing large-scale behaviour via spatially averaged bifurcation diagrams. The key message is that, across a large range of parameter values, fluid flow can induce plankton blooms and mean-field population dynamics that are distinct from those predicted for well-mixed systems. The implications for oceanic population dynamic studies are manifest: we argue that the formation of HABs will depend strongly on the physical and biological state of the ecosystem, and that local increases in zooplankton heterogeneity are likely to precede phytoplankton blooms.

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Mathematical analysis of plankton population dynamics

Malaysian Journal of Fundamental and Applied Sciences ◽

10.11113/mjfas.v16n1.1383 ◽

2020 ◽

Vol 16 (1) ◽

pp. 109-114

Author(s):

Fatin Nadiah Yussof ◽

Normah Maan ◽

Nadzri Reba

Keyword(s):

Mathematical Model ◽

Population Dynamics ◽

Harmful Algal Blooms ◽

Algal Blooms ◽

Health Effect ◽

Economic Loss ◽

Toxic Chemicals ◽

Toxic Phytoplankton ◽

Interior Equilibrium ◽

Plankton Population

Harmful algal blooms (HABs) event that causes enormous economic loss and health effect raises concerns among environmentalists. In this paper, a mathematical model of interaction between nutrient, toxin-producing phytoplankton (TPP), non-toxic phytoplankton (NTP), zooplankton, and toxic chemicals is proposed to study on how the process of these HABs occurred. The model of interaction is represented by Ordinary Differential Equations (ODEs) and stability analysis of the model is conducted. Several conditions for the system to be stable around trivial and interior equilibrium point are obtained. From the analysis, it is observed that under nutrient limitation, the amounts of toxic chemicals secreted out by the TPP are increased. As a result, NTP population and zooplankton population are affected by the situation. If this situation is prolonged, this will result in the extinction of both populations. Overall, this study shows that TPP release more toxic chemicals when the nutrient is limited and gives a better understanding on the occurrence of HABs event.

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255. Public Health Response to Harmful Algal Blooms

10.3320/1.2765781 ◽

2001 ◽

Author(s):

P. Webb

Keyword(s):

Public Health ◽

Harmful Algal Blooms ◽

Algal Blooms ◽

Public Health Response ◽

Health Response

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National coastal management challenges and needs

Shore & Beach ◽

10.34237/1008843 ◽

2020 ◽

pp. 34-43

Author(s):

Nicole Elko ◽

Tiffany Roberts Briggs

Keyword(s):

Coastal Management ◽

Harmful Algal Blooms ◽

Algal Blooms ◽

Local Community ◽

Extreme Event ◽

Technical Information ◽

Interdisciplinary Approach ◽

Beach Erosion ◽

The U.S

In partnership with the U.S. Geological Survey Coastal and Marine Hazards and Resources Program (USGS CMHRP) and the U.S. Coastal Research Program (USCRP), the American Shore and Beach Preservation Association (ASBPA) has identified coastal stakeholders’ top coastal management challenges. Informed by two annual surveys, a multiple-choice online poll was conducted in 2019 to evaluate stakeholders’ most pressing problems and needs, including those they felt most ill-equipped to deal with in their day-to-day duties and which tools they most need to address these challenges. The survey also explored where users find technical information and what is missing. From these results, USGS CMHRP, USCRP, ASBPA, and other partners aim to identify research needs that will inform appropriate investments in useful science, tools, and resources to address today’s most pressing coastal challenges. The 15-question survey yielded 134 complete responses with an 80% completion rate from coastal stakeholders such as local community representatives and their industry consultants, state and federal agency representatives, and academics. Respondents from the East, Gulf, West, and Great Lakes coasts, as well as Alaska and Hawaii, were represented. Overall, the prioritized coastal management challenges identified by the survey were: Deteriorating ecosystems leading to reduced (environmental, recreational, economic, storm buffer) functionality, Increasing storminess due to climate change (i.e. more frequent and intense impacts), Coastal flooding, both Sea level rise and associated flooding (e.g. nuisance flooding, king tides), and Combined effects of rainfall and surge on urban flooding (i.e. episodic, short-term), Chronic beach erosion (i.e. high/increasing long-term erosion rates), and Coastal water quality, including harmful algal blooms (e.g. red tide, sargassum). A careful, systematic, and interdisciplinary approach should direct efforts to identify specific research needed to tackle these challenges. A notable shift in priorities from erosion to water-related challenges was recorded from respondents with organizations initially formed for beachfront management. In addition, affiliation-specific and regional responses varied, such as Floridians concern more with harmful algal blooms than any other human and ecosystem health related challenge. The most common need for additional coastal management tools and strategies related to adaptive coastal management to maintain community resilience and continuous storm barriers (dunes, structures), as the top long-term and extreme event needs, respectively. In response to questions about missing information that agencies can provide, respondents frequently mentioned up-to-date data on coastal systems and solutions to challenges as more important than additional tools.

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