scholarly journals A model of oxygen and nitrogen biogeochemical response to hydrodynamic regimes in the Yarra River estuary

2015 ◽  
Keyword(s):  
River Estuary ◽  
Yarra River

Distribution of species of Cu, Pb, Zn and Cd in a water profile of the Yarra river estuary

1978 ◽  
Vol 12 (2) ◽  
pp. 119-125 ◽  
Author(s):  
H Blutstein
Keyword(s):  
River Estuary ◽  
Water Profile ◽  
Yarra River

scholarly journals Hydrodynamic controls on oxygen dynamics in a riverine salt wedge estuary, the Yarra River estuary, Australia

2014 ◽  
Vol 18 (4) ◽  
pp. 1397-1411 ◽  
Author(s):  
L. C. Bruce ◽  
P. L. M. Cook ◽  
I. Teakle ◽  
M. R. Hipsey
Keyword(s):  
River Flow ◽  
River Estuary ◽  
Oxygen Depletion ◽  
Effect Of Temperature ◽  
Biogeochemical Model ◽  
Salt Wedge ◽  
Antecedent Conditions ◽  
Biogeochemical Models ◽  
Seasonal Hypoxia ◽  
Yarra River

Abstract. Oxygen depletion in coastal and estuarine waters has been increasing rapidly around the globe over the past several decades, leading to decline in water quality and ecological health. In this study we apply a numerical model to understand how salt wedge dynamics, changes in river flow and temperature together control oxygen depletion in a micro-tidal riverine estuary, the Yarra River estuary, Australia. Coupled physical–biogeochemical models have been previously applied to study how hydrodynamics impact upon seasonal hypoxia; however, their application to relatively shallow, narrow riverine estuaries with highly transient patterns of river inputs and sporadic periods of oxygen depletion has remained challenging, largely due to difficulty in accurately simulating salt wedge dynamics in morphologically complex areas. In this study we overcome this issue through application of a flexible mesh 3-D hydrodynamic–biogeochemical model in order to predict the extent of salt wedge intrusion and consequent patterns of oxygen depletion. The extent of the salt wedge responded quickly to the sporadic riverine flows, with the strength of stratification and vertical density gradients heavily influenced by morphological features corresponding to shallow points in regions of tight curvature ("horseshoe" bends). The spatiotemporal patterns of stratification led to the emergence of two "hot spots" of anoxia, the first downstream of a shallow region of tight curvature and the second downstream of a sill. Whilst these areas corresponded to regions of intense stratification, it was found that antecedent conditions related to the placement of the salt wedge played a major role in the recovery of anoxic regions following episodic high flow events. Furthermore, whilst a threshold salt wedge intrusion was a requirement for oxygen depletion, analysis of the results allowed us to quantify the effect of temperature in determining the overall severity and extent of hypoxia and anoxia. Climate warming scenarios highlighted that oxygen depletion is likely to be exacerbated through changes in flow regimes and warming temperatures; however, the increasing risk of hypoxia and anoxia can be mitigated through management of minimum flow allocations and targeted reductions in organic matter loading. A simple statistical model (R2 > 0.65) is suggested to relate riverine flow and temperature to the extent of estuary-wide anoxia.

scholarly journals Controls on oxygen dynamics in a riverine salt-wedge estuary – a three-dimensional model of the Yarra River estuary, Australia

2013 ◽  
Vol 10 (7) ◽  
pp. 9799-9845
Author(s):  
L. C. Bruce ◽  
P. L. M. Cook ◽  
I. Teakle ◽  
M. R. Hipsey
Keyword(s):  
Nutrient Dynamics ◽  
River Estuary ◽  
Oxygen Depletion ◽  
Model Verification ◽  
Low Flow ◽  
Biogeochemical Model ◽  
Three Dimensional Model ◽  
Salt Wedge ◽  
Biogeochemical Models ◽  
Yarra River

Abstract. Oxygen depletion in estuarine waters is an important factor governing water quality and ecological health. A complex and dynamic balance of physical and biogeochemical factors drive the extent and persistence of hypoxia and anoxia making it difficult to predict. An increased understanding of the effect of changing flow regimes and temperature on patterns of estuarine oxygen depletion is required to support ongoing management. Coupled physical and biogeochemical models have been applied to study the interaction of physical processes and seasonal hypoxia, however, application to riverine estuaries with tight curvature and more sporadic periods of oxygen depletion is rare. In this study we apply a finite volume 3-D hydrodynamic-biogeochemical model (TUFLOW-FV–FABM) to the Yarra River estuary, Australia, in order to predict the extent of salt-wedge intrusion and consequent patterns of oxygen depletion. The predictive capacity of the model was evaluated using a series of model verification metrics and the results evaluated to determine the dominant mechanisms affecting salt-wedge position and the extent and persistence of anoxia and hypoxia. Measures of model fit indicated that the model reasonably captured the strength of stratification and the position and extent of the salt wedge (r2 ~ 0.74). The extent of the salt wedge intrusion was controlled by riverine flow and the strength of stratification or mixing dominated by topographical features corresponding to areas of tight curvature ("horseshoe" bends). The model predicted that the extent of anoxic waters generally mimicked the extent of the salt wedge (r2 ~ 0.65) increasing during periods of low flow and reduced following episodic high flow events. The results showed two sporadically isolated "hot spots" of anoxia, the first downstream of the horseshoe bend and the second downstream of a sill. Simulated oxygen concentrations indicated that whilst a threshold salt wedge intrusion was a requirement of oxygen depletion, temperature was critical in determining the extent of hypoxia and anoxia in the estuary. These findings highlight the importance of how seasonal changes in flow events and environmental flow management can impact on estuarine oxygen depletion in a warming climate. This study provides an improved understanding of the controls on hypoxia and anoxia in riverine estuaries, which is essential to support improved prediction of nutrient dynamics and ecological heath.

Aromatic hydrocarbons in waters of Port Phillip Bay and the Yarra River estuary

1984 ◽  
Vol 35 (2) ◽  
pp. 119 ◽  
Author(s):  
JD Smith ◽  
WA Maher
Keyword(s):  
Aromatic Hydrocarbons ◽  
Coastal Waters ◽  
River Estuary ◽  
Fluorescence Emission ◽  
Wide Distribution ◽  
Small Contribution ◽  
Emission Analysis ◽  
Fuel Oils ◽  
Yarra River

Determination of aromatic hydrocarbons in coastal waters, using solvent extraction and fluorescence emission analysis, shows wide distribution of fuel oils with only a small contribution from crude oil. Oil concentrations are reported as equivalent amounts of m-terphenyl (T) or pyrene (P). Observed concentrations in Port Phillip Bay are generally 0.2-0.3 pg l-1 (T) and 0.1-0.2 pg l-1 (P), with higher values in Corio Bay and the Yarra River estuary.

Determination of Iron in Suspended Matter and Sediments of the Yarra River Estuary, and the Distribution of Copper, Lead, Zinc and Manganese in the Sediments

1979 ◽  
Vol 30 (6) ◽  
pp. 731 ◽  
Author(s):  
JD Smith ◽  
PJ Milne
Keyword(s):  
Acetic Acid ◽  
Particulate Matter ◽  
Acetic Acid Solution ◽  
River Estuary ◽  
Hydroxylamine Hydrochloride ◽  
Suspended Particulate ◽  
Lead Zinc ◽  
Copper Lead ◽  
Yarra River

Sediments from the Yarra River estuary were analysed for Cu, Pb, Zn, Mn, Fe and Ca extractable in hydroxylamine hydrochloride-acetic acid solution. Strong correlation of Pb and Zn with extractable Fe was observed. The behaviour of Cu indicated that it was not only controlled by the hydrated iron oxides, but that some may be organically bound. The effects of salinity on the suspended particulate matter were examined, and variations in the amount of extractable Fe in the particulate matter observed.

Hypoxic events stimulate nitrogen recycling in a shallow salt-wedge estuary: The Yarra River estuary, Australia

2012 ◽  
Vol 57 (5) ◽  
pp. 1427-1442 ◽  
Author(s):  
Keryn L. Roberts ◽  
Vera M. Eate ◽  
Bradley D. Eyre ◽  
Daryl P. Holland ◽  
Perran L. M. Cook
Keyword(s):  
River Estuary ◽  
Nitrogen Recycling ◽  
Salt Wedge ◽  
Yarra River

Integrated conceptual modelling of faecal contamination in an urban estuary catchment

2015 ◽  
Vol 72 (9) ◽  
pp. 1472-1480 ◽  
Author(s):  
Dusan Jovanovic ◽  
Rebekah Henry ◽  
Rhys Coleman ◽  
Ana Deletic ◽  
David McCarthy
Keyword(s):  
Boundary Conditions ◽  
River Estuary ◽  
Water Bodies ◽  
Urban Stormwater ◽  
Sensitivity Testing ◽  
Faecal Contamination ◽  
E Coli ◽  
Model Efficiency ◽  
Contamination Levels ◽  
Yarra River

Urban stormwater is regarded as a key input of faecal contamination in receiving water bodies and therefore, a major concern for health risks associated with aquatic recreation. Wastewater leakages, cross connections and overflows, together with faeces washed from surfaces during rainfall events, are possible origins of faecal contamination which enter these water bodies through stormwater drains. This paper applies conceptual models to a case study of the Yarra River estuary to understand the relative importance of fluxes derived from an urban creek and the 219 urban stormwater pipes which drain directly to the estuary as compared with other inputs, such as the Yarra River itself. Existing hydrologic-microorganism models were used for the estimation of the inputs from riverine and urban stormwater fluxes. These predictions were applied as boundary conditions for a new, highly simplified, model which accounts for the transport and survival of faecal microorganisms in the estuary. All models were calibrated using a rich dataset, containing over 2,000 measured Escherichia coli concentrations. Mass balances from the riverine and stormwater models indicate the limited influence of urban stormwater drains on the estuary during dry weather; less than 0.05% to 10% (5th and 95th percentile; median 0.5%) of the total daily E. coli load entering the estuary was derived from urban stormwater drains. While wet weather contributions from stormwater drains could be more significant (2% to 50%; 5th and 95th percentile), the average contribution remained marginal (median 10%). Sensitivity testing of the estuarine microorganism model by switching off stormwater boundary conditions resulted in minimal model efficiency reduction; this may reflect the low average daily contribution from urban stormwater drains. While these results confirm previous studies which show that E. coli loads derived from stormwater drains are dwarfed by other inputs, it is essential to note that these results also demonstrate that some conditions reveal the opposite; high proportions from stormwater are possible when combined with low riverine inputs and high urban rainfall. Furthermore, this study focuses on the overall impacts of direct urban stormwater inputs on the faecal contamination levels within the estuary, and localized impacts would certainly require further investigation.

Climate-associated trends and variability in ichthyoplankton phenology from the longest continuous larval fish time series on the east coast of the United States

2020 ◽  
Vol 650 ◽  
pp. 269-287
Author(s):  
WC Thaxton ◽  
JC Taylor ◽  
RG Asch
Keyword(s):  
United States ◽  
Environmental Variability ◽  
Larval Fish ◽  
Interspecific Interactions ◽  
River Estuary ◽  
Atlantic Multidecadal Oscillation ◽  
The United States ◽  
Larval Survival ◽  
Ecological Communities ◽  
Northerly Wind

As the effects of climate change become more pronounced, variation in the direction and magnitude of shifts in species occurrence in space and time may disrupt interspecific interactions in ecological communities. In this study, we examined how the fall and winter ichthyoplankton community in the Newport River Estuary located inshore of Pamlico Sound in the southeastern United States has responded to environmental variability over the last 27 yr. We relate the timing of estuarine ingress of 10 larval fish species to changes in sea surface temperature (SST), the Atlantic Multidecadal Oscillation, the North Atlantic Oscillation, wind strength and phenology, and tidal height. We also examined whether any species exhibited trends in ingress phenology over the last 3 decades. Species varied in the magnitude of their responses to all of the environmental variables studied, but most shared a common direction of change. SST and northerly wind strength had the largest impact on estuarine ingress phenology, with most species ingressing earlier during warm years and delaying ingress during years with strong northerly winds. As SST warms in the coming decades, the average date of ingress of some species (Atlantic croaker Micropogonias undulatus, summer flounder Paralichthys dentatus, pinfish Lagodon rhomboides) is projected to advance on the order of weeks to months, assuming temperatures do not exceed a threshold at which species can no longer respond through changes in phenology. These shifts in ingress could affect larval survival and growth since environmental conditions in the estuarine and pelagic nursery habitats of fishes also vary seasonally.

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