Spatial-Monthly Variations and Influencing Factors of Dissolved Oxygen in Surface Water of Zhanjiang Bay, China

Journal of Marine Science and Engineering, Journal Year: 2020, Volume and Issue: 8(6), P. 403 - 403

Published: June 2, 2020

Dissolved oxygen (DO) is one of the most important factors for maintaining a healthy marine ecosystem. The information DO in large estuaries or bays with entrances has been widely studied, while it relatively limited bay narrow entrance which vulnerable to human activities. Zhanjiang Bay, located northwestern South China Sea, very and suffers from strong anthropogenic activities obvious seasonal variations environmental parameters. In this study, we analyzed spatial monthly DO, apparent utilization (AOU), percent saturation (DO-saturation), related parameters surface water Bay find out controlling dynamics DO. Different many other coastal ecosystems, concentrations reached minimum values late spring early autumn. phytoplankton bloom summer months, was high nutrients brought by rainfall-induced terrestrial inputs, contributed that phenomenon. Though chlorophyll (Chl a) were observed both months December, DO-saturation low AOU months. Rainfall-induced discharge had chemical demand, much average hydrological year decreased seaward, increased indicating influence input. highest annual Chl concentration, value near Donghai Dam. This indicated construction Dam significant influences on environment Bay.

Language: Английский

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Modelling the Influence of Riverine Inputs on the Circulation and Flushing Times of Small Shallow Estuaries

Estuaries and Coasts, Journal Year: 2020, Volume and Issue: 44(1), P. 54 - 69

Published: July 1, 2020

Abstract Simple flushing time calculations for estuarine systems can be used as proxies eutrophication susceptibility. However, more complex methods are required to better understand entire systems. Understanding of the hydrodynamics driving circulation and times in small, eutrophic, temperate estuaries is less advanced than larger counterparts due lack data difficulties accurately modelling small-scale This paper uses microtidal Christchurch Harbour estuary Southern UK a case study elucidate physical controls on susceptibility small shallow basins. A depth-averaged hydrodynamic model has been configured investigate processes with particular emphasis understanding impact riverine inputs this system. Results indicate control changes from tidally fluvially driven increase. Flushing times, calculated using particle tracking method, that system take long 132 h flush when river flow low, or short 12 input exceptionally high. When total into 30 m 3 s −1 , tidal flux dominant control, which results high during neap tides. Conversely, greater fluvial flux, spring tides longer at neaps. The methodology presented here shows spatial scales possible but highlights importance determine variability across

Language: Английский

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Influence of nutrient enrichment on temporal and spatial dynamics of dissolved oxygen within northern temperate estuaries

Environmental Monitoring and Assessment, Journal Year: 2021, Volume and Issue: 193(12)

Published: Nov. 15, 2021

In temperate estuaries of the southern Gulf St. Lawrence, intermittent seasonal anoxia coupled with phytoplankton blooms is a regular occurrence in watersheds dominated by agricultural land use. To examine spatial relationship between dissolved oxygen and throughout estuary to assist designing monitoring programs, depth profiles chlorophyll measurements were taken bi-weekly from May December 18 estuaries. five those estuaries, data loggers set measure at hourly intervals multiple locations within subsequent year. The primary hypothesis was that upper (first 10% area) predictive mid-estuary (50% area). second hypoxia/superoxia influenced temperature tidal flushing. Oxygen conducted first year study provided preliminary support related estuary. However, deployed 50% area did not show as strong correlation expected (less than half variance explained). strength declined towards end summer. Spatial decoupling suggested influence local conditions. Chlorophyll concentration seemed also be dependent on conditions it appeared presence sustained typically occurring 7 14 days anoxia. practical implication for one location most severely impacted part sufficient fully evaluate severity eutrophication effects.

Language: Английский

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Holocene environmental evolution and relative sea-level change in the Oka estuary (Urdaibai Biosphere Reserve, northern Spain)

Estuarine Coastal and Shelf Science, Journal Year: 2023, Volume and Issue: 286, P. 108310 - 108310

Published: April 3, 2023

The Holocene environmental evolution in coastal areas, including deltas and estuaries, is vital to understanding dynamics how they may change the future. Here, we studied of Oka estuary (Urdaibai Biosphere Reserve, northern Spain) from sedimentary cores that were 11–49 m long. We applied a multi-proxy approach benthic foraminifera grain size, temporal framework radiocarbon dates reconstruct paleoenvironments. assemblages varied near-marine (allochthonous autochthonous hyaline species such as Lobatula lobatula, Rosalina irregularis, Ammonia tepida Haynesina germanica) brackish intertidal (autochthonous A. H. salt-marsh agglutinated Trochammina inflata Entzia macrescens) environments. Grain size analysis supported foraminiferal sequences sand-dominated environments mud-dominated chronology was constrained by thirty four plant macrofossils, marine shells wood fragments. Our paleoenvironmental reconstructions used produce an updated local relative sea-level (RSL) record based on new data, revised reconstructions, age recalibration previous research. Marine limiting showed RSL changed above −20.4 ± 0.2 at ∼9100 cal. yrs. BP −4.2 ∼6700 BP. In late Holocene, index points (SLIPs) reconstructed position −2.7 1.2 ∼4900 −1.4 ∼1500 Estimates rates Errors-in-Variables Integrated Gaussian Process (EIV-IGP) model show gradually rose 0.3 2.1 mm yr−1 Holocene. There progressive shallowing rise reduced during Between ∼9000 7000-6000 pre-Holocene fluvial gravels (Lowstand Systems Tract) replaced both sandy sediments (Transgressive Tract). After ∼7000-6000 deposited (Highstand sequence overlain anthropogenic deposits derived agricultural, dredging dumping activities since 18th century (Anthropogenic broadly consistent with studies Spain, although it places onset Highstand Tract ∼2000 years earlier.

Language: Английский

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Differences in the colonization success and impact of non-indigenous and other expanding copepod species on the zooplankton of two contrasting estuaries of the Bay of Biscay

Biological Invasions, Journal Year: 2020, Volume and Issue: 22(11), P. 3239 - 3267

Published: Aug. 20, 2020

Language: Английский

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Otolith shape and elemental signatures provide insights into the connectivity of euryhaline Chelon labrosus inhabiting two close estuaries with different burdens of xenoestrogens in the Southern Bay of Biscay

Marine Environmental Research, Journal Year: 2023, Volume and Issue: 189, P. 106075 - 106075

Published: July 1, 2023

Intersex gonads have been observed in thicklip grey mullet Chelon labrosus, inhabiting estuaries with high burdens of xenoestrogens the Southeast Bay Biscay, but knowledge population connectivity among is lacking for this euryhaline fish species. This study investigates structure C. labrosus using otolith shape and elemental signatures 60 adults (overall length ∼ 38 cm) from two 21 nautic miles apart, one a incidence intersex condition (Gernika), other pristine (Plentzia). Otolith analyses were performed elliptical Fourier descriptors, while whole sagittae obtained by inductively coupled plasma mass spectrophotometry. Univariate multivariate statistics applied to determine if show patterns homogeneity between estuaries. The data indicated significant differences composition mullets Gernika Plentzia. Elemental mainly driven Sr, Li (both higher Plentzia) Ba (higher Gernika). 98% re-classification success rate stepwise linear discriminant function analysis suggests that Plentzia individuals form separated units. limited these close would indicate different life history exposure chemicals, which might explain prevalence its absence Plenztia.

Language: Английский

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Hydrogeochemical characteristics of Thrissur Kole Wetland, Southwest India

International Journal of River Basin Management, Journal Year: 2024, Volume and Issue: unknown, P. 1 - 14

Published: March 14, 2024

Surface water samples collected from Thrissur Kole wetland (UNSECO-protected Ramsar Site) were analysed for hydrogeochemical characteristics. The objectives of this work to: (i) study the spatial and seasonal variability in quality (ii) analyse characteristics different types suitability status irrigation. Remarkable season-wise station-wise variation salinity was attributed to mixing freshwater seawater. Relatively lower values pH during post-monsoon due discharge mineralisation organic matter. Besides natural sources, agriculture activities, droppings birds also serve as sources nutrients wetland. average relative abundance major cations anions Cl- > Na+ Mg2+ K+ SO42- HCO3- Ca2+. In addition, contribution dissolved ions tidal ingression established by dominance magnesium sulphate. Based on Piper plot, three hydro-chemical facies (Ca–Mg-HCO3 type, Ca–Mg-Cl-SO4 Na-K-Cl-SO4 type) identified. Irrigational throughout excellent monsoon per irrigational indices. plot indicated that surface chemistry controlled silicate weathering with seawater anthropogenic sources.

Language: Английский

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Response of the phytoplankton community to the cessation of wastewater discharges in the Urdaibai estuary (SE Bay of Biscay) based on PIGMENTUM analysis of HPLC pigments

Marine Environmental Research, Journal Year: 2024, Volume and Issue: 200, P. 106668 - 106668

Published: Aug. 3, 2024

Phytoplankton responds rapidly to nutrient availability variations, becoming a useful indicator for eutrophication and/or management actions reduce it. The present study evaluated the medium-term response of phytoplankton community temperate estuary (Urdaibai estuary) cessation discharges from wastewater treatment-plant (WWTP), comparing physicochemical conditions and before (2020) after (2022) sewerage works. led decrease ammonium phosphate, causing decreases biomass in outer middle increases surroundings WWTP. Community composition also changed, recording an increase prasinoxanthin-containing algae's contribution total biomass, shift inner estuary, mainly flagellates (alloxanthin-containing chlorophyll b-containing algae) diatoms, which could be prompted by change nutrient-ratios nitrogen source, might indicate recuperation system.

Language: Английский

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Hypoxia cycle in shallow lakes during winter (ice-covered to melting period): Stable and decay, hypoxia, and recovery phases

The Science of The Total Environment, Journal Year: 2024, Volume and Issue: 954, P. 176625 - 176625

Published: Oct. 5, 2024

Language: Английский

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Is reducing phosphorus inputs sufficient to reduce hypoxia in estuaries? The example of the Loire estuary

Estuarine Coastal and Shelf Science, Journal Year: 2024, Volume and Issue: unknown, P. 109110 - 109110

Published: Dec. 1, 2024

Language: Английский

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