Seagrass responses to and recovery (?) from seven years of brown tide

Most harmful algal blooms are relatively short, violent paroxysms to aquatic systems. The Texas brown tide was unique in its 7-year domination of upper Laguna Madre wherein it reduced light penetrating 1 m from 31 to 63% on an annual basis between June 1990 and May 1997. In response, seagrasses declined in biomass in deep areas for two years. Over the next three years, bare areas opened up in the deepest areas of the seagrass meadow and the outer seagrass boundary retreated landward. In the last two years of the brown tide, regression of the dominant species, Halodule wrightii, slowed and stopped, and Halophila engelmanni, a previously minor species, revegetated some areas. Subsequent to cessation of meadow retreat, water clarity improved to pre-brown tide levels, consistent with the hypothesis that regeneration of nutrients from retreating sea grass meadow may have been the source of the nutrient subsidy required to sustain the brown tide at high concentration. However, after a short interlude of clear water and Halodule recovery, a resurgence of the bloom occurred and areas of regrowth succumbed. Although human activities did not seem to be involved in initiation or persistence of the brown tide, nutrients brought in by runoff from agricultural lands may have contributed to the return of bloom conditions.

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Where's the Grass? Disappearing Submerged Aquatic Vegetation and Declining Water Quality in Lake Mattamuskeet

Journal of Fish and Wildlife Management ◽

10.3996/082016-jfwm-068 ◽

2017 ◽

Vol 8 (2) ◽

pp. 401-417 ◽

Cited By ~ 4

Author(s):

Michelle C. Moorman ◽

Tom Augspurger ◽

John D. Stanton ◽

Adam Smith

Keyword(s):

Water Quality ◽

North Carolina ◽

Harmful Algal Blooms ◽

Algal Blooms ◽

Submerged Aquatic Vegetation ◽

Aquatic Vegetation ◽

Suspended Sediments ◽

Water Clarity ◽

Aquatic Life ◽

Current Water

Abstract Major threats to aquatic systems such as shallow lakes can include declining water quality, the loss of macrophyte beds, and the occurrence of harmful algal blooms. Often, these changes go unnoticed until a shift from a clear, oligotrophic system dominated by macrophyte beds to a turbid, eutrophic system dominated by phytoplankton and associated harmful algal blooms has occurred. Lake Mattamuskeet, which mostly lies within the boundary of Mattamuskeet National Wildlife Refuge, North Carolina, is a shallow lake that has recently experienced a reduction in water clarity and macrophyte beds, also referred to as submerged aquatic vegetation (SAV), and an increase in nutrients, phytoplankton, harmful algal blooms, and cyanotoxin production. At Lake Mattamuskeet, SAV coverage and water clarity declined between the 1980s and 2015. During the same time, significantly increasing trends in nitrogen, phosphorus, turbidity, suspended sediments, chlorophyll a, and pH occurred. Current water-quality conditions (2012–2015) are not conducive to SAV survival and, in some cases, do not meet North Carolina water-quality standards for the protection of aquatic life. Water clarity declines appear to predate the SAV die-offs on the east side. Moving forward, SAV will serve as a primary indicator for lake health; and lake monitoring, research, and management efforts will focus on the restoration of aquatic grasses and water quality at Lake Mattamuskeet.

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The brown tide algae, Aureococcus anophagefferens and Aureoumbra lagunensis (Pelagophyceae), allelopathically inhibit the growth of competing microalgae during harmful algal blooms

Limnology and Oceanography ◽

10.1002/lno.10714 ◽

2017 ◽

Vol 63 (2) ◽

pp. 985-1003 ◽

Cited By ~ 6

Author(s):

Yoonja Kang ◽

Christopher J. Gobler

Keyword(s):

Harmful Algal Blooms ◽

Algal Blooms ◽

Brown Tide ◽

Aureococcus Anophagefferens ◽

Aureoumbra Lagunensis

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Mesozooplankton Community Dynamics and Grazing Potential Across Algal Bloom Cycles in a Subtropical Estuary

Frontiers in Marine Science ◽

10.3389/fmars.2021.734270 ◽

2021 ◽

Vol 8 ◽

Author(s):

L. Holly Sweat ◽

Hunter Alexander ◽

Edward J. Phlips ◽

Kevin B. Johnson

Keyword(s):

Harmful Algal Blooms ◽

Algal Blooms ◽

Community Dynamics ◽

Algal Bloom ◽

Indian River Lagoon ◽

Environmental Data ◽

Brown Tide ◽

Mesozooplankton Community ◽

Indian River ◽

Subtropical Estuary

Mesozooplankton, as abundant grazers of microalgae in coastal systems, have the potential to prevent or mitigate harmful algal blooms (HABs) and their effects. The Indian River Lagoon (IRL) is a subtropical estuary in eastern Florida (United States) where repeated blooms, dominated by the toxic dinoflagellate Pyrodinium bahamense, the brown tide species Aureoumbra lagunensis, pico/nano planktonic cyanobacteria and other nano-eukaryotes, have highlighted the need to better understand fluctuations in the grazing potential of mesozooplankton populations across bloom cycles. Mesozooplankton and abiotic environmental data were collected at five sites in the northern IRL system at 6-week intervals from November 2013 through June 2016. A total of 107 taxa from 14 phyla were detected. Communities varied across sites, dates and between bloom and non-bloom periods, with densities up to 338 individuals L–1. Eight taxa comprising 85–94% of the total population at each site were identified as primary potential grazers, including barnacle nauplii, cladocerans, adult copepods, gastropod veligers, larvaceans, and polychaete metatrochophores. Although abundant, the estimated grazing potential of the primary taxa, calculated from their measured densities and previously published grazing rates, suggest that mesozooplankton lack the capacity to suppress phytoplankton once they reach bloom levels. These findings illustrate the utility of monitoring data and underscore the importance of systematically evaluating algal bloom controls with a consideration for the dynamic conditions of each unique ecosystem.

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Modeling the Dynamics of Chlorophyll-a in Bohai Bay Using a Bayesian Network Approach

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.610-613.1056 ◽

2012 ◽

Vol 610-613 ◽

pp. 1056-1059

Author(s):

Xiao Fu Xu ◽

Hong Tao Nie ◽

Jian Hua Tao

Keyword(s):

Bayesian Network ◽

Chlorophyll A ◽

Physical Environment ◽

Harmful Algal Blooms ◽

Algal Blooms ◽

Bohai Bay ◽

Relative Importance ◽

High Concentration ◽

Ecological Processes ◽

Average Accuracy

The relative importance of chemical, physical and ecological processes in driving phytoplankton dynamics is poorly understood in Bohai Bay. Here we developed a Bayesian network (BN) model to integrate many of these processes and model the growth of chlorophyll-a in coastal area of Bohai Bay. BNs use probabilistic relationships rather than deterministic rules to quantify the cause and effect assumptions. The result shows that predictions of the model have an average accuracy of 65%, and chlorophyll-a dynamics were primarily driven by nutrients rather than physical environment and biological system. High concentration of nutrients was the suitable environmental condition for harmful algal blooms (HABs).

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Algal Blooms and Cyanotoxins in Jordan Lake, North Carolina

Toxins ◽

10.3390/toxins10020092 ◽

2018 ◽

Vol 10 (2) ◽

pp. 92 ◽

Cited By ~ 14

Author(s):

Daniel Wiltsie ◽

Astrid Schnetzer ◽

Jason Green ◽

Mark Vander Borgh ◽

Elizabeth Fensin

Keyword(s):

North Carolina ◽

Harmful Algal Blooms ◽

Algal Blooms ◽

Solid Phase ◽

Water Reservoir ◽

Water Clarity ◽

Environmental Forcing ◽

Hypoxic Conditions ◽

Drinking Water Reservoir ◽

Cyanobacterial Harmful Algal Blooms

The eutrophication of waterways has led to a rise in cyanobacterial, harmful algal blooms (CyanoHABs) worldwide. The deterioration of water quality due to excess algal biomass in lakes has been well documented (e.g., water clarity, hypoxic conditions), but health risks associated with cyanotoxins remain largely unexplored in the absence of toxin information. This study is the first to document the presence of dissolved microcystin, anatoxin-a, cylindrospermopsin, and β-N-methylamino-l-alanine in Jordan Lake, a major drinking water reservoir in North Carolina. Saxitoxin presence was not confirmed. Multiple toxins were detected at 86% of the tested sites and during 44% of the sampling events between 2014 and 2016. Although concentrations were low, continued exposure of organisms to multiple toxins raises some concerns. A combination of discrete sampling and in-situ tracking (Solid Phase Adsorption Toxin Tracking [SPATT]) revealed that microcystin and anatoxin were the most pervasive year-round. Between 2011 and 2016, summer and fall blooms were dominated by the same cyanobacterial genera, all of which are suggested producers of single or multiple cyanotoxins. The study’s findings provide further evidence of the ubiquitous nature of cyanotoxins, and the challenges involved in linking CyanoHAB dynamics to specific environmental forcing factors are discussed.

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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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Water Quality Trends in Hamilton Harbour: 1987 to 1995

Water Quality Research Journal ◽

10.2166/wqrj.1996.027 ◽

1996 ◽

Vol 31 (3) ◽

pp. 473-484 ◽

Cited By ~ 9

Author(s):

Murray N. Charlton ◽

Robin Le Sage

Keyword(s):

Algal Blooms ◽

Action Plan ◽

Secchi Depth ◽

Water Clarity ◽

Nutrient Loads ◽

Hamilton Harbour ◽

Near Shore ◽

The Media ◽

Park Area ◽

Water Quality Trends

Abstract A series of water samples and Secchi depth measurements were conducted in Hamilton Harbour between 1987 and 1995. The data indicate little recent improvement in the harbour generally. Detection of real improvements may require high frequency sampling and a more extensive sample grid once a cause for improvement is in place. Some measures, such as chlorophyll and Secchi depth, approach RAP initial goals sometimes during recent years, but algal blooms still occur, which prevent attainment of satisfactory average conditions. The cause of aesthetic improvements in water clarity reported in the media was investigated with sampling along an inshore-offshore transect and intense Secchi measurements in the LaSalle Park area. The data are consistent with a transient clarifying effect of zebra mussels on structures near shore. The need to reduce nutrient loads as recommended in the Remedial Action Plan continues.

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