Impact of Freshwater Discharge on Production and Transfer of Materials in the Marine Environment

Smetacek, Victor

doi:10.1007/978-3-642-70886-2_6

Cited by 18 publications

(13 citation statements)

References 36 publications

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“…O gênero Skeletonema apresenta organismos neríticos k-estrategistas, fato associado à presença de águas turbulentas (Smetacek 1986), como as observadas na ilha Canela. Bem representados ao longo do período de estudo, os organismos deste gênero não foram identificados ao nível específico.…”

Section: Discussionunclassified

Microfitoplâncton de águas costeiras amazônicas: Ilha Canela (Bragança, PA, Brasil)

et al. 2008

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RESUMO -(Microfitoplâncton de águas costeiras amazônicas: Ilha Canela (Bragança, PA, Brasil)). Variações sazonal e nictemeral do microfitoplâncton foram estudadas em uma estação fixa (00º46'37,2''S-046º43'24,5''W), localizada em uma área costeira próxima à ilha Canela (Norte do Brasil), durante os meses de setembro e dezembro/2004 (período seco) e março e junho/2005 (período chuvoso). As amostras destinadas à análise qualitativa do fitoplâncton foram obtidas a partir da filtragem de 400 L de água, através de uma rede planctônica (65 µm de abertura de malha), durante marés de sizígia, em intervalos regulares de três horas, por um período de 24 horas. O material coletado foi fixado com formol neutro a 4%. Paralelamente a essas coletas foi medida a salinidade da superfície da água. A salinidade apresentou variação significativa ao longo do período de estudo, variando entre 26,1 (junho/2005) e 39,0 (dezembro/2004), caracterizando o ambiente como eualino-polialino. Foram identificados 130 táxons incluídos nas divisões Cyanophyta (dois táxons), Bacillariophyta (115 táxons) e Dinophyta (13 táxons). As diatomáceas dominaram o microfitoplâncton da área, sendo Asterionellopsis glacialis, Dimeregramma minor, Skeletonema sp. e Thalassiosira subtilis os táxons mais freqüentes e abundantes. Os altos valores de salinidade condicionaram a maior representatividade das espécies marinhas neríticas, polialóbias. Os processos de ressuspensão provocados pelos ventos e arrebentação das ondas promoveram intercâmbios entre as populações planctônicas e ticoplanctônicas, dentre as quais as espécies Dimeregramma minor, Triceratium biquadratum e T. pentacrinus representaram novas ocorrências para as águas costeiras do litoral amazônico. Palavras-chave: fitoplâncton, composição, Ilha Canela, costa amazônicaABSTRACT -(Microphytoplankton of Amazon coastal waters: Canela Island (Bragança, Pará State, Brazil)). Seasonal and nyctemeral variations of the microphytoplankton were studied at a fixed station (00º46'37.2''S-046º43'24.5''W) on Canela Island (North Brazil) in September and December/2004 (dry season) and in March and June/2005 (rainy season). Samples for qualitative phytoplankton studies were obtained by filtering 400 L of surface water in the surf zone of the island through plankton nets (65 µm mesh size). Field work was carried out during spring tides and samples were collected every 3 hours during a 24-hour period. The collected material was fixed in neutral formaldehyde at 4%. Simultaneously, salinity of the water surface was also measured. Salinity showed significant variation throughout the study period, ranging from 26.1 (June/2005) to 39.0 (December/2004), characterizing the environment as euhalinepolyhaline. A total of 130 taxa were identified, belonging to Cyanophyta (two taxa), Bacillariophyta (115 taxa) and Dinophyta (13 taxa). Diatoms were the dominant group of microphytoplankton at Canela Island. Asterionellopsis glacialis, Dimeregramma minor, Skeletonema sp. and Thalassiosira subtilis were the most frequent and abundant tax...

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Section: Discussionunclassified

Microfitoplâncton de águas costeiras amazônicas: Ilha Canela (Bragança, PA, Brasil)

et al. 2008

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“…Parameters such as temperature, nutrient concentration, and salinity can change drastically within hours as a result of a large precipitation event (Schroeder 1978, Browder 1985, Smetacek 1986, Allen & Turner 1989, Blood & Vernberg 1992, Wilber 1992). In our experiments, tve addressed the question of how larvae and embryos are affected by storm-related fluctuations in salinity levels.…”

Section: Discussionmentioning

confidence: 99%

“…Such drops in salinity occur throughout the entire water column, d u e to the wellmixed nature of the North Inlet Estuary. With very large freshwater inputs, such reductions for the entire water column are also seen in estuarine systems that are normally stratified (Schroeder 1978, Browder 1985, Smetacek 1986, Allen & Turner 1989, Wilber 1992.…”

Section: Introductionmentioning

confidence: 97%

Short-term fluctuations in salinity:effects on planktonic invertebrate larvae

Richmond¹

1996

Mar. Ecol. Prog. Ser.

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ABSTRACT. Estuarine habitats are characterized by environmental changes on many time scales. While certain physical parameters change on a regular, predictable basis, rapid environmental fluctuatlons can also occur as a result of stochastic events. For example, rainstorms are frequent, unpredictable events that can cause dramatic changes in the estuarine environment, in short periods of time As a result of storm precipitation and terrestrial freshwater runoff, estuarine sallnity can drop in excess of 2 0 ?~ in 6 h. Our research focuses on the effects of these storm-induced salinity fluctuations on estua n n e embryos and larvae in terms of growth, mortality, rate of development, and activity. We studied 2 species of estuarine invertebrates: the embryos and larvae of the mud snail Ilyanassa obsoleta and the larvae of the marine polychaete Arenicola cristata. In both species, greater reductions in salinity resulted in smaller larvae. Both the duration of salinity reduction and the age of embryos and larvae when exposed to a sallnity reduction affected growth rates: longer and earlier (relative to embryonic or larval age) storms had a greater effect on growth rates, resulting in smaller larvae. Both species also exhibited changes in activity when exposed to salinity reductions: I. obsoleta larvae swam significantly less at 10'!:*), while A. cristata larvae displayed a delay in activities associated with the sequence of development from s w i m m~n g trochophore, to crawling larva, to settled metamorphic juvenile. Our results show that stochastic events may have a significant impact on the growth and development of pre-settlement estuarine invertebrates, implying ecological effects on recruitment success.

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“…Diatom blooms tend to sink following nutrient depletion (Smetacek, 1986), a fate facilitated by increasing stratification. Should the mixing characteristics remain adequate, si:p and Si:N ratios and bulk nutrient concentrations will continue to decline in support of the increasing diatom biomass.…”

Section: Nutrient Ratio Hypothesismentioning

confidence: 99%

Primary Production and the Global Epidemic of Phytoplankton Blooms in the Sea: A Linkage?

Smayda

1989

Novel Phytoplankton Blooms

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Impact of Freshwater Discharge on Production and Transfer of Materials in the Marine Environment

Cited by 18 publications

References 36 publications

Microfitoplâncton de águas costeiras amazônicas: Ilha Canela (Bragança, PA, Brasil)

Microfitoplâncton de águas costeiras amazônicas: Ilha Canela (Bragança, PA, Brasil)

Short-term fluctuations in salinity:effects on planktonic invertebrate larvae

Primary Production and the Global Epidemic of Phytoplankton Blooms in the Sea: A Linkage?

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