Thirty years – Alexandrium fundyense cyst, bloom dynamics and shellfish toxicity in the Bay of Fundy, eastern Canada

Martin, Jennifer L.; LeGresley, Murielle M.; Hanke, Alex

doi:10.1016/j.dsr2.2013.08.004

Cited by 33 publications

(34 citation statements)

References 29 publications

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“…A compilation of A. fundyense bloom dynamics from the Bay of Fundy indicated that, consistent with our findings, the first appearance of A. fundyense cells was, on average, 3 wk earlier in the first decade of this century compared with the final 12 y of the 20th century and that maximum cell densities during blooms increased more than threefold over the same time period (23). Furthermore, with the exception of 1999, the start of bloom season predicted by our study for the NW Atlantic was significantly correlated (P < 0.01) with the date at which 40 Alexandrium cells L −1 were first observed within the Bay of Fundy from 1988 to 2010 [SI Appendix, Fig.…”

supporting

confidence: 75%

Ocean warming since 1982 has expanded the niche of toxic algal blooms in the North Atlantic and North Pacific oceans

Gobler

Doherty

Hattenrath-Lehmann

et al. 2017

Proc. Natl. Acad. Sci. U.S.A.

383

225

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Global ocean temperatures are rising, yet the impacts of such changes on harmful algal blooms (HABs) are not fully understood. Here we used high-resolution sea-surface temperature records (1982 to 2016) and temperature-dependent growth rates of two algae that produce potent biotoxins, Alexandrium fundyense and Dinophysis acuminata, to evaluate recent changes in these HABs. For both species, potential mean annual growth rates and duration of bloom seasons significantly increased within many coastal Atlantic regions between 40°N and 60°N, where incidents of these HABs have emerged and expanded in recent decades. Widespread trends were less evident across the North Pacific, although regions were identified across the Salish Sea and along the Alaskan coastline where blooms have recently emerged, and there have been significant increases in the potential growth rates and duration of these HAB events. We conclude that increasing ocean temperature is an important factor facilitating the intensification of these, and likely other, HABs and thus contributes to an expanding human health threat.Alexandrium | Dinophysis | climate change | sea-surface temperature | bloom duration H armful algal blooms (HABs) negatively affect aquatic ecosystems, fisheries, tourism, and human health. HABs such as Alexandrium fundyense and Dinophysis acuminata are particularly concerning, as they produce saxitoxin and okadaic acid, respectively, toxins that can cause the human health syndromes paralytic and diarrhetic shellfish poisoning (PSP and DSP, respectively). The global range, regional intensity, and frequency of HABs have increased in recent decades (1, 2). This phenomenon is, in part, related to increasing awareness and improved monitoring of HABs (2) and, in some cases, the intensification of anthropogenic nutrient loading in coastal zones (3). Although there have been multiple predictions regarding the response of HABs to future climate change (2, 4), the ability to conclusively relate changes in HAB phenology and distribution to rising ocean temperatures has been a challenge.Globally, the geographic ranges of phytoplankton are frequently controlled by sea-surface temperatures [SSTs (2, 5)], and the realized niches of HABs are often defined by a narrow range of temperatures (2, 5-8). As global oceans warm (9, 10) and the distribution of ocean temperatures changes (11,12), it is expected that the distribution and range of phytoplankton and HABs will also shift (2, 4). Observations and modeling studies have shown that climate change-driven warming of ocean water is unevenly distributed (12), particularly along coastlines (11, 13). Consequently, temperature-driven changes in HAB distributions are likely to vary along coastlines and among ocean basins. Presently, the extent to which changes in HAB occurrence and intensity are related to changing ocean temperatures is unresolved.To assess the relationship between HABs and global temperature change, some recent studies have used physical and biogeochemical output from global circulation ...

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supporting

confidence: 75%

Ocean warming since 1982 has expanded the niche of toxic algal blooms in the North Atlantic and North Pacific oceans

Gobler

Doherty

Hattenrath-Lehmann

et al. 2017

Proc. Natl. Acad. Sci. U.S.A.

383

225

View full text Add to dashboard Cite

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“…Thus the BOF cyst accumulation zone (Martin and White, 1988; Martin et al, this issue) lies below the recirculating gyre found at the mouth of the BOF (Aretxabaleta et al, 2008, 2009), as would be expected if cysts formed during the blooms in those waters eventually accumulate in bottom sediments. The mid-coast Maine seedbed broadens in the offshore direction south of Penobscot Bay, consistent with the veering offshore of the MCC.…”

Section: Discussionmentioning

confidence: 67%

“…Numerous studies have enumerated cysts for a wide range of habitats and dinoflagellate species, identifying seedbeds and linking these to blooms (e.g., Anderson and Morel, 1979; Genovesi et al, 2009; Crespo et al, 2011; Ni Rhataille and Raine, 2011; Angeles et al., 2010, 2012; Martin et al, this issue). Few, however, have studied the dynamics and evolution of those seedbeds over multiple bloom cycles and years.…”

Section: Discussionmentioning

confidence: 99%

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Alexandrium fundyense cysts in the Gulf of Maine: Long-term time series of abundance and distribution, and linkages to past and future blooms

Anderson

Keafer

Kleindinst

et al. 2014

Deep Sea Research Part II: Topical Studies in Oceanography

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113

111

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Here we document Alexandrium fundyense cyst abundance and distribution patterns over nine years (1997 and 2004-2011) in the coastal waters of the Gulf of Maine (GOM) and identify linkages between those patterns and several metrics of the severity or magnitude of blooms occurring before and after each autumn cyst survey. We also explore the relative utility of two measures of cyst abundance and demonstrate that GOM cyst counts can be normalized to sediment volume, revealing meaningful patterns equivalent to those determined with dry weight normalization. Cyst concentrations were highly variable spatially. Two distinct seedbeds (defined here as accumulation zones with > 300 cysts cm−3) are evident, one in the Bay of Fundy (BOF) and one in mid-coast Maine. Overall, seedbed locations remained relatively constant through time, but their area varied 3-4 fold, and total cyst abundance more than 10 fold among years. A major expansion of the mid-coast Maine seedbed occurred in 2009 following an unusually intense A. fundyense bloom with visible red-water conditions, but that feature disappeared by late 2010. The regional system thus has only two seedbeds with the bathymetry, sediment characteristics, currents, biology, and environmental conditions necessary to persist for decades or longer. Strong positive correlations were confirmed between the abundance of cysts in both the 0-1 and the 0-3 cm layers of sediments in autumn and geographic measures of the extent of the bloom that occurred the next year (i.e., cysts → blooms), such as the length of coastline closed due to shellfish toxicity or the southernmost latitude of shellfish closures. In general, these metrics of bloom geographic extent did not correlate with the number of cysts in sediments following the blooms (blooms → cysts). There are, however, significant positive correlations between 0-3 cm cyst abundances and metrics of the preceding bloom that are indicative of bloom intensity or vegetative cell abundance (e.g., cumulative shellfish toxicity, duration of detectable toxicity in shellfish, and bloom termination date). These data suggest that it may be possible to use cyst abundance to empirically forecast the geographic extent of the forthcoming bloom and, conversely, to use other metrics from bloom and toxicity events to forecast the size of the subsequent cyst population as the inoculum for the next year's bloom. This is an important step towards understanding the excystment/encystment cycle in A. fundyense bloom dynamics while also augmenting our predictive capability for this HAB-forming species in the GOM.

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“…Station GM, and the high cyst concentrations in the region east and north of Grand Manan, are in a triangle-shaped, fine-grained sedimentary environment east of Grand Manan extending northward toward the St. John River (Fig. 3) (Martin et al, 2014). This region of seabed is identified as LaHave clay (Fader et al, 1977; Fig.…”

Section: Discussionmentioning

confidence: 99%

Investigating the importance of sediment resuspension in Alexandrium fundyense cyst population dynamics in the Gulf of Maine

Butman

Aretxabaleta

Dickhudt

et al. 2014

Deep Sea Research Part II: Topical Studies in Oceanography

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Cysts of Alexandrium fundyense, a dinoflagellate that causes toxic algal blooms in the Gulf of Maine, spend the winter as dormant cells in the upper layer of bottom sediment or the bottom nepheloid layer and germinate in spring to initiate new blooms. Erosion measurements were made on sediment cores collected at seven stations in the Gulf of Maine in the autumn of 2011 to explore if resuspension (by waves and currents) could change the distribution of over-wintering cysts from patterns observed in the previous autumn; or if resuspension could contribute cysts to the water column during spring when cysts are viable. The mass of sediment eroded from the core surface at 0.4 Pa ranged from 0.05 kg m−2 near Grand Manan Island, to 0.35 kg m−2 in northern Wilkinson Basin. The depth of sediment eroded ranged from about 0.05 mm at a station with sandy sediment at 70 m water depth on the western Maine shelf, to about 1.2 mm in clayey–silt sediment at 250 m water depth in northern Wilkinson Basin. The sediment erodibility measurements were used in a sediment-transport model forced with modeled waves and currents for the period October 1, 2010 to May 31, 2011 to predict resuspension and bed erosion. The simulated spatial distribution and variation of bottom shear stress was controlled by the strength of the semi-diurnal tidal currents, which decrease from east to west along the Maine coast, and oscillatory wave-induced currents, which are strongest in shallow water. Simulations showed occasional sediment resuspension along the central and western Maine coast associated with storms, steady resuspension on the eastern Maine shelf and in the Bay of Fundy associated with tidal currents, no resuspension in northern Wilkinson Basin, and very small resuspension in western Jordan Basin. The sediment response in the model depended primarily on the profile of sediment erodibility, strength and time history of bottom stress, consolidation time scale, and the current in the water column. Based on analysis of wave data from offshore buoys from 1996 to 2012, the number of wave events inducing a bottom shear stress large enough to resuspend sediment at 80 m ranged from 0 to 2 in spring (April and May) and 0 to 10 in winter (October through March). Wave-induced resuspension is unlikely in water greater than about 100 m deep. The observations and model results suggest that a millimeter or so of sediment and associated cysts may be mobilized in both winter and spring, and that the frequency of resuspension will vary interannually. Depending on cyst concentration in the sediment and the vertical distribution in the water column, these events could result in a concentration in the water column of at least 104 cysts m−3. In some years, resuspension events could episodically introduce cysts into the water column in spring, where germination is likely to be facilitated at the time of bloom formation. An assessment of the quantitative effects of cyst resuspension on bloom dynamics in any particular year requires more detailed investigation.

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Thirty years – Alexandrium fundyense cyst, bloom dynamics and shellfish toxicity in the Bay of Fundy, eastern Canada

Cited by 33 publications

References 29 publications

Ocean warming since 1982 has expanded the niche of toxic algal blooms in the North Atlantic and North Pacific oceans

Ocean warming since 1982 has expanded the niche of toxic algal blooms in the North Atlantic and North Pacific oceans

Alexandrium fundyense cysts in the Gulf of Maine: Long-term time series of abundance and distribution, and linkages to past and future blooms

Investigating the importance of sediment resuspension in Alexandrium fundyense cyst population dynamics in the Gulf of Maine

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