Artificially oxygenating the Swan River estuary increases dissolved oxygen concentrations in the water and at the sediment interface

Larsen, Sarah; Kilminster, Kieryn; Mantovanelli, Alessandra; Goss, Zoe; Evans, Georgina C.; Bryant, Lee D.; Mcginnis, Daniel Frank

doi:10.1016/j.ecoleng.2018.12.032

Cited by 22 publications

(11 citation statements)

References 34 publications

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“…However, in heavily nutrient-impacted situations, the increased flushing from neap to spring tides is not sufficient to compensate for the oxygen demand in upper to central parts of the estuary, and the net oxygen remains at zero, apparently uninfluenced by tidal changes in the short term as seen clearly in the Kildare estuary. This has been confirmed elsewhere through artificial oxygenation as an alternative to tidal oxygen transport, resulting in increases in dissolved oxygen in the water (Larsen et al, 2019). At some estuaries in the present study, the oxygen consumption was presumably less severe, and in the case of Bideford where cyclical hypoxia was observed seems to have been overcome by increased flushing.…”

Section: Discussionsupporting

confidence: 85%

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

Coffin

Knysh

Roloson

et al. 2021

Environ Monit Assess

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

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Section: Discussionsupporting

confidence: 85%

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

Coffin

Knysh

Roloson

et al. 2021

Environ Monit Assess

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“…Artificial oxygenation methods, such as constructed wetlands, are capable of increasing saturated oxygen levels as well as facilitating the removal of pollutants from water (Dong et al 2012). Similarly, replenishment of oxygen in bottom waters through enhanced vertical circulation has been proposed for lakes (Dunalska and Wiśniewski 2016), while artificial oxygenation has been shown to be effective for some lotic ecosystems (Larsen et al 2019). Such management interventions may prove crucial to maintaining current native populations, while resisting the establishment and ecological impacts of IAS.…”

Section: Discussionmentioning

confidence: 99%

Breathing space: deoxygenation of aquatic environments can drive differential ecological impacts across biological invasion stages

et al. 2021

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The influence of climate change on the ecological impacts of invasive alien species (IAS) remains understudied, with deoxygenation of aquatic environments often-overlooked as a consequence of climate change. Here, we therefore assessed how oxygen saturation affects the ecological impact of a predatory invasive fish, the Ponto-Caspian round goby (Neogobius melanostomus), relative to a co-occurring endangered European native analogue, the bullhead (Cottus gobio) experiencing decline in the presence of the IAS. In individual trials and mesocosms, we assessed the effect of high, medium and low (90%, 60% and 30%) oxygen saturation on: (1) functional responses (FRs) of the IAS and native, i.e. per capita feeding rates; (2) the impact on prey populations exerted; and (3) how combined impacts of both fishes change over invasion stages (Pre-invasion, Arrival, Replacement, Proliferation). Both species showed Type II potentially destabilising FRs, but at low oxygen saturation, the invader had a significantly higher feeding rate than the native. Relative Impact Potential, combining fish per capita effects and population abundances, revealed that low oxygen saturation exacerbates the high relative impact of the invader. The Relative Total Impact Potential (RTIP), modelling both consumer species’ impacts on prey populations in a system, was consistently higher at low oxygen saturation and especially high during invader Proliferation. In the mesocosm experiment, low oxygen lowered RTIP where both species were present, but again the IAS retained high relative impact during Replacement and Proliferation stages at low oxygen. We also found evidence of multiple predator effects, principally antagonism. We highlight the threat posed to native communities by IAS alongside climate-related stressors, but note that solutions may be available to remedy hypoxia and potentially mitigate impacts across invasion stages.

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“…Artificial oxygenation may be used to locally negate the negative impacts of low dissolved oxygen in the bottom waters of vertically stratified and eutrophic estuaries, and in regions upstream of weirs that restrict saline intrusion (Huang et al, 2018;Larsen et al, 2019). Artificial oxygenation is an engineering measure to supply oxygen generated mechanically to anoxic or hypoxic bottom waters, aerating the water and increasing redox potential at the sediment-water interface to reduce sediment nutrient release (Toffolon et al, 2013).…”

Section: Complementary Restoration Strategiesmentioning

confidence: 99%

“…Artificial oxygenation is an engineering measure to supply oxygen generated mechanically to anoxic or hypoxic bottom waters, aerating the water and increasing redox potential at the sediment-water interface to reduce sediment nutrient release (Toffolon et al, 2013). This technique has been more commonly used in deep freshwater lakes and reservoirs (Gantzer et al, 2009;Toffolon et al, 2013), but was successfully applied to shallow freshwaters upstream of the Swan River Estuary, Perth, whereby dissolved oxygen concentrations increased immediately in the water column post installation, with improvements after several days at the sediment-water interface increasing oxygen fluxes into the sediment (Larsen et al, 2019). Previous attempts to address deoxygenation in the salt wedge region of the Swan River Estuary were undertaken through artificial destratification by application of bubble plumes to mix surface and bottom waters (Hamilton et al, 2001).…”

Section: Complementary Restoration Strategiesmentioning

confidence: 99%

Environmental Flow Requirements of Estuaries: Providing Resilience to Current and Future Climate and Direct Anthropogenic Changes

Chilton

Hamilton

Nagelkerken

et al. 2021

Front. Environ. Sci.

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Estuaries host unique biodiversity and deliver a range of ecosystem services at the interface between catchment and the ocean. They are also among the most degraded ecosystems on Earth. Freshwater flow regimes drive ecological processes contributing to their biodiversity and economic value, but have been modified extensively in many systems by upstream water use. Knowledge of freshwater flow requirements for estuaries (environmental flows or E-flows) lags behind that of rivers and their floodplains. Generalising estuarine E-flows is further complicated by responses that appear to be specific to each system. Here we critically review the E-flow requirements of estuaries to 1) identify the key ecosystem processes (hydrodynamics, salinity regulation, sediment dynamics, nutrient cycling and trophic transfer, and connectivity) modulated by freshwater flow regimes, 2) identify key drivers (rainfall, runoff, temperature, sea level rise and direct anthropogenic) that generate changes to the magnitude, quality and timing of flows, and 3) propose mitigation strategies (e.g., modification of dam operations and habitat restoration) to buffer against the risks of altered freshwater flows and build resilience to direct and indirect anthropogenic disturbances. These strategies support re-establishment of the natural characteristics of freshwater flow regimes which are foundational to healthy estuarine ecosystems.

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Artificially oxygenating the Swan River estuary increases dissolved oxygen concentrations in the water and at the sediment interface

Cited by 22 publications

References 34 publications

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

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

Breathing space: deoxygenation of aquatic environments can drive differential ecological impacts across biological invasion stages

Environmental Flow Requirements of Estuaries: Providing Resilience to Current and Future Climate and Direct Anthropogenic Changes

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