Nutrient and Oxygen Redistribution During a Spring Neap Tidal Cycle in a Temperate Estuary

Webb, Katie; D’Elia, Christopher F.

doi:10.1126/science.207.4434.983

Cited by 66 publications

(16 citation statements)

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“…In the BC phosphate and salinity correlate negatively at spring tide (R 2 = -0.68), indicating that the phosphate input occurs from brackish surface waters. Webb and D´Elia (1979) have corroborated previous reports that the release of phosphate from sediment is enhanced at low oxygen tensions. They also ascertained that vertical mixing accompanying spring-tidal destratification promotes oxygen replenishment in deep water, allowing aerobic processes to proceed, and accelerates the input of benthos-regenerated nutrients into the euphotic zone.…”

Section: Discussionsupporting

confidence: 81%

Short-term variability and transport of nutrients and Chlorophyll-a in Bertioga Channel, São Paulo State, Brazil

et al. 2005

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A B S T R A C TShort-term variability of nutrients, chlorophyll-a (Chl-a) and seston (TSS) concentrations were followed up at a fixed station in the Bertioga Channel (BC), Southeastern Brazil, over two full tidal cycles of neap and spring tides, during the winter of 1991. Simultaneous data on hydrographic structure, tidal level and currents allowed the computation of the net transport of those properties. Tidal advection and freshwater flow were the main forcing agents on the water column structure, nutrient availability and Chl-a distribution. Dissolved inorganic nitrogen and phosphate average values were high (16.88 and 0.98 µM, respectively, at neap tide and 10.18 and 0.77µM at spring tide). Despite N and P availability, Chl-a average values were low: 1.13 in the neap and 3.11 mg m -3 in the spring tide, suggesting that the renovation rate of BC waters limits phytoplankton accumulation inside the estuary. The highest Chl-a was associated with the entrance of saltier waters, while the high nutrient concentrations were associated with brackish waters. Nutrients were exported on both tides, TSS and Chl-a were exported on the spring tide and Chl-a was imported on the neap tide. The study of the main transport components indicated that this system is susceptible to the occasional introduction of pollutants from the coastal area, thus presenting a facet of potential fragility. R E S U M OVariações de curta escala das concentrações de nutrientes, clorofila-a (Cl-a) e séston foram acompanhadas em uma estação fixa no canal de Bertioga (CB), sudeste do Brasil, em dois ciclos completos de maré de quadratura e sizígia, no inverno de 1991. Dados simultâneos da estrutura hidrográfica, marés e correntes permitiram calcular o transporte resultante daquelas propriedades. A advecção por maré e o fluxo de água doce foram as principais forçantes da estrutura hidrográfica e da distribuição de nutrientes e Cl-a. As concentrações médias de NID e fosfato foram altas (respectivamente: 16,88 e 0,98 µM na quadratura e 10,18 e 0,77 µM na sizígia). Apesar da disponibilidade de N e P, os valores médios de Cl-a foram baixos: 1,13 mg m -3 (na quadratura) e 3,11 mg m -3 (sizígia), sugerindo que a alta taxa de renovação das águas do CB limitam o acúmulo de fitoplâncton. Os maiores valores de Cl-a relacionaram-se à entrada de águas costeiras enquanto que as altas concentrações de nutrientes foram relacionadas às águas salobras. Os nutrientes dissolvidos foram exportados em ambas as marés, séston e Cl-a foram exportados na sizígia e, na quadratura, a Cl-a foi importada. O estudo dos principais componentes do transporte indicou uma susceptibilidade desse sistema à introdução de poluentes oriundos da área costeira, revelando uma potencial fragilidade ambiental.

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Section: Discussionsupporting

confidence: 81%

Short-term variability and transport of nutrients and Chlorophyll-a in Bertioga Channel, São Paulo State, Brazil

et al. 2005

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“…A factor that seems to have been generally overlooked in studies of estuarine transport is the impact of the spring-neap tidal cycle on vertical mixing. It is well known that stratification tends to break down during spring tide conditions because of turbulent mixing (Webb & D'Elia 1980, Geyer 1995, Peters 1997. Stratification of larvae that is engendered by depth preference or a habit of vertical migration may relax under these conditions as well.…”

Section: Abstract: Estuaries · Selective Tidal-stream Transport · Fimentioning

confidence: 99%

Mechanisms promoting upriver transport of larvae of two fish species in the Hudson River estuary

Schultz¹,

Lwiza²,

Fencil³

et al. 2003

Mar. Ecol. Prog. Ser.

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“…This is surprising, given that L. brevis presumably has exceptional tolerance among cephalopods to salinity and other physical conditions and that Chesapeake Bay is one of the largest, most diverse, physically variable estuaries in the world, with tributaries and rivers within the system constituting a shoreline a few thousand kilometers long. Within Chesapeake Bay, physical and biological processes operate rapidly and intensely on many different temporal and spatial scales: large-scale pycnoclines extending almost the entire length of the bay frequently develop throughout the spring (Brandt et al 1986); significant phytoplankton blooms arise in the late spring/early summer (Pinet 1992); regions of bottom-water hypoxia may develop in the late summer for weeks or even between tides when organic matter deposition is high and vertical mixing is difficult because of water-column stratification (Webb & D'Elia 1980); hundreds of northern and southern species of fishes converge in the bay throughout the year (Geer & Austin 1995); and dramatic decreases in salinity and water temperature occur rapidly in the spring and winter, respectively (Brandt et al 1986). Given that most squids evolved to reside in physically stable, offshore environments where interactions with fishes are low relative to inshore environments (O'Dor & Webber 1986, Wells 1994, the presence of L. brevis in a highly variable, euryhaline environment rich in nektonic fauna such as Chesapeake Bay is intriguing.…”

Section: Introductionmentioning

confidence: 99%

Distribution of the euryhaline squid Lolliguncula brevis in Chesapeake Bay: effects of selected abiotic factors

Bartol¹,

Mann²,

Vecchione³

2002

Mar. Ecol. Prog. Ser.

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The majority of cephalopods are thought to have limitations arising from physiology and locomotion that exclude them from shallow, highly variable, euryhaline environments. The brief squid Lolliguncula brevis may be a notable exception because it tolerates low salinities, withstands a wide range of environmental conditions, and swims readily in shallow water. Little is known about the distribution of L. brevis in Chesapeake Bay, a diverse and highly variable estuary. Therefore, a survey of L. brevis was conducted in the Virginia portion of Chesapeake Bay from 1993 to 1997 using a 9.1 m otter trawl, and the effects of selected factors on squid presence were assessed using logistic regression analysis. During spring through fall, L. brevis was collected over a wide range of bottomwater salinities (17.9 to 35.0 ‰), bottom-water temperatures (8.1 to 29.6°C), bottom-water dissolved oxygen levels (1.9 to 14.6 mg O 2 l -1 ), and depths (1.8 to 29.9 m), but it was not present in trawls conducted during winter in. L. brevis, especially juveniles < 60 mm dorsal mantle length (DML), were abundant, frequently ranking in the upper 12% of overall annual nektonic trawl catches, and during the fall of some years, ranking second to anchovies. The probability of catching a squid increased in Chesapeake Bay at higher salinities and water temperatures, and was much greater in normoxic than in hypoxic waters; these variables had a profound influence on both annual and seasonal variability in distribution. Salinity had the largest influence on squid distribution, with squid being completely absent from the bay when salinity was <17.9 ‰ and most abundant in the fall when salinity was highest (despite declines in water temperature). Squid were most prevalent at depths between 10 and 15 m. The results of this study suggest that L. brevis is an important component of the Chesapeake Bay ecosystem when salinities and water temperatures are within tolerance limits and that unlike other squids, L. brevis may be well-equipped for an inshore, euryhaline existence.

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Nutrient and Oxygen Redistribution During a Spring Neap Tidal Cycle in a Temperate Estuary

Cited by 66 publications

References 10 publications

Short-term variability and transport of nutrients and Chlorophyll-a in Bertioga Channel, São Paulo State, Brazil

Short-term variability and transport of nutrients and Chlorophyll-a in Bertioga Channel, São Paulo State, Brazil

Mechanisms promoting upriver transport of larvae of two fish species in the Hudson River estuary

Distribution of the euryhaline squid Lolliguncula brevis in Chesapeake Bay: effects of selected abiotic factors

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