Importance of life cycle events in the population dynamics of Gonyaulax tamarensis

Anderson, Donald M.; Chisholm, Sallie W.; Watras, Carl J.

doi:10.1007/bf00392734

Cited by 179 publications

(198 citation statements)

References 27 publications

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“…Since the syringes were about 10 cm apart and separate syringes were used for cell counts, nutrients, and salinity, the data are reported at different vertical intervals. Profiles of irradiance (PAR, 400 to 700 nm) were made with a Li Cor flat plate (cosine) quantum sensor (LI-192s) at 0.5 m intervals in 1980, and with a Biospherical Instruments spherical (scalar) sensor (QSP-200) in 1981 and1983. Temperature profiles were obtained with a YSI Model 33 S-C-T meter.…”

Section: Methodsmentioning

confidence: 99%

Selective retention of two dinoflagellates in a well-mixed estuarine embayment: the importance of diel vertical migration and surface avoidance

Anderson¹,

Stolzenbach²

1985

Mar. Ecol. Prog. Ser.

113

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Diel vertical migration patterns of the dinoflagellates Gonyaulax tamarensis and Heterocapsa triquetra were monitored in an estuarine embayment subject to localized blooms of both species. A concurrent study of tidal flushing using a dye tracer demonstrated an efficient, densitydriven mixing process that exchanged water within the embayment at a rate of approximately 0.5 d-'. Loss rates of the whole pond populations of G. tamarensis and H. trjquetra cells were smaller, ranging between 0.02 and 0.13 d-'. The cells were thus able to maintain a non-mixed distribution even under weakly stratified conditions. This selective retention of the 2 species relative to water exchange was due to the differential advection of surface and bottom waters through the inlet channel and the general avoidance of high irradiance surface layers by the dinoflagellates. Both species migrated to irradiances equivalent to 30% of summer sunlight when nutrients were presumably non-limiting, resulting in subsurface aggregations 1 to 2 m deep. Under nutrient-limited conditions, G. tamarensjsmigration was restricted to irradiance at or below 10 to 15% summer sunlight. Planozygotes (a life-cycle stage preceding cyst formation) migrated in a manner indistinguishable from the remainder of the nutrientlimited G. tamarensis population. The results help to explain the dominance of dinoflagellates in such embayments, the localization of their blooms, and the distribution of their resting cysts in the region.

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Section: Methodsmentioning

confidence: 99%

Selective retention of two dinoflagellates in a well-mixed estuarine embayment: the importance of diel vertical migration and surface avoidance

Anderson¹,

Stolzenbach²

1985

Mar. Ecol. Prog. Ser.

113

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“…Many of these common dinoflagellate species are known to produce viable cysts during their life cycle (e.g., Anderson et al 1983Anderson et al , 2003. Cysts may initiate new blooms if conditions are suitable, or sustain populaitons throughout the yea, germinating from bottom sediments.…”

Section: Urea Fertilization May Alter Phytoplankton Species Compositimentioning

confidence: 99%

Ocean urea fertilization for carbon credits poses high ecological risks

Glibert¹,

Azanza²,

Burford³

et al. 2008

Marine Pollution Bulletin

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The proposed plan for enrichment of the Sulu Sea, Philippines, a region of rich marine biodiversity, with thousands of tonnes of urea in order to stimulate algal blooms and sequester carbon is flawed for multiple reasons. Urea is preferentially used as a nitrogen source by some cyanobacteria and dinoflagellates, many of which are neutrally or positively buoyant. Biological pumps to the deep sea are classically leaky, and the inefficient burial of new biomass makes the estimation of a net loss of carbon from the atmosphere questionable at best. The potential for growth of toxic dinoflagellates is also high, as many grow well on urea and some even increase their toxicity when grown on urea. Many toxic dinoflagellates form cysts which can settle to the sediment and germinate in subsequent years, forming new blooms even without further fertilization. If large-scale blooms do occur, it is likely that they will contribute to hypoxia in the bottom waters upon decomposition. Lastly, urea production requires fossil fuel usage, further limiting the potential for net carbon sequestration. The environmental and economic impacts are potentially great and need to be rigorously assessed.

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“…Reduction in estuarine primary production has been linked to the increase in water turbidity promoted by dredging (EWA-OBOHO et al, 2008) and differential sediment transport (CHEN et al, 2005). Resuspension of bottom sediments can also bring phytoplankton resting stages to the water column as vegetative cells (SHIKATA et al, 2008), leading to the development of blooms that may include red tide species (ANDERSON et al, 1983). Input of nutrient loads (CONLEY, 2000;DE JONGE et.…”

Section: Introductionmentioning

confidence: 99%

Temporal variability of chlorophyll-a in the São Vicente estuary

et al. 2012

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A B S T R A C TEstuaries are extremely dynamic environments that are vulnerable to anthropogenic alterations. Thus, monitoring phytoplankton abundances and composition is an essential tool for the prediction of eutrophication and its effects on coastal ecosystems. Phytoplankton biomass, as chlorophyll-a, in the São Vicente estuary (Brazil) varies in response to tidal cycles and seasonal rainfall. Objectives. To present two datasets designed to assess the relationship between chlorophyll-a and changes in water turbidity driven by tide and rain. Methods. Weekly observations were made in the shallow embayment (February to September 2008; site 1) and observations recorded on alternate days (summer 2010, site 2). Results. At site 1, turbidity differed between high and low tides, but on most days was over 3000 RU, maintaining moderate chlorophyll-a levels (4 mg.m -3 ) and only two blooms developed during low turbidity. Site 2 mean turbidity was 1500 RU, nutrient level was higher during neap tides and phytoplankton blooms were mainly observed at the end of neap tides at 15-day intervals, dominated by chain-forming diatoms and occasionally flagellates and pennate diatoms. Conclusions. Taxonomic composition of the blooms was different and their frequency altered by events characterized by intense freshwater discharges from the Henry Borden Hydroelectric Dam (> 9*106.m 3 ), inhibiting phytoplankton accumulation during neap tide periods. R E S U M OEstuários são ambientes dinâmicos e susceptíveis a alterações antropogênicas. Nesses ambientes, torna-se imprescindível monitoramento do fitoplâncton na previsão da eutrofização e de seus efeitos para o ecossistema. No estuário de São Vicente (Brasil) a biomassa fitoplanctônica, como clorofila-a, varia sazonalmente em resposta às chuvas e marés. O presente estudo visa apresentar dois programas de monitoramento para detectar florações fitoplanctônicas em relação a turbidez da água guiada pelas marés e chuvas. Métodos. As observações foram semanais na porção rasa (Fevereiro a Setembro de 2008; área 1) e observações em dias alternados no canal (verão de 2010; área 2). Os resultados mostram que a área 1, turbidez acima de 3000 RU manteve níveis de clorofila-a médios (4 mg.m -3 ) e duas florações ocorreram apenas em baixa turbidez, sendo esta diferente entre marés alta e baixa. Na área 2, a turbidez manteve-se entre 1500 RU, os nutrientes foram maiores durante as marés de quadratura, e as florações tiveram frequência de aproximadamente 15 dias, no final da quadratura, predominando diatomáceas em cadeia e eventualmente flagelados e diatomáceas penadas. A composição taxonômica variou entre florações e o padrão quinzenal foi significativamente alterado durante eventos com alta descarga de água doce oriundos da usina hidroelétrica Henry Borden (> 9*106.m 3 ) o que impediu o acúmulo de fitoplâncton no período das quadraturas.

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Importance of life cycle events in the population dynamics of Gonyaulax tamarensis

Cited by 179 publications

References 27 publications

Selective retention of two dinoflagellates in a well-mixed estuarine embayment: the importance of diel vertical migration and surface avoidance

Selective retention of two dinoflagellates in a well-mixed estuarine embayment: the importance of diel vertical migration and surface avoidance

Ocean urea fertilization for carbon credits poses high ecological risks

Temporal variability of chlorophyll-a in the São Vicente estuary

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