Impacts of Suspended Sediment on Nearshore Benthic Light Availability Following Dam Removal in a Small Mountainous River: In Situ Observations and Statistical Modeling

Glover, Hannah; Ogston, A. S.; Miller, Ian; Eidam, Emily; Rubin, Steve; Berry, Helen

doi:10.1007/s12237-019-00602-5

Cited by 12 publications

(8 citation statements)

References 53 publications

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“…The increase in sediment supply due to tributary dam releases can have either negative or positive impacts on an estuary. Negative impacts include decreases in water clarity or high rates of sediment accretion that affect submerged vegetation (Glover et al 2019;Hamberg et al 2017) or lead to shifts in ecosystem community composition (Cloern et al 2007;Rubin et al 2017). On the positive side, increases in sediment supply might help tidal marshes keep up with sea level rise or reduce shoreline erosion rates (Warrick et al 2019).…”

Section: Estuarine Impacts Of Sediment From Dam Removalsmentioning

confidence: 99%

“…Increased sediment concentrations and deposition rates from dam removals can have adverse ecosystem impacts. High deposition rates near the mouth of the Elwha were linked to reductions in macroalgae and changes in the abundance of invertebrate and fish taxa (Rubin et al 2017), and were associated with decreased light availability (Glover et al 2019). However, increased sediment inputs can also be beneficial to a coastline, particularly in regions with limited sediment supply, where sediment from dam removals can help mitigate shoreline erosion and promote marsh resilience (Ganju 2019;Ganju et al 2013).…”

Section: Introductionmentioning

confidence: 99%

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Watershed Suspended Sediment Supply and Potential Impacts of Dam Removals for an Estuary

Ralston

Yellen

Woodruff

2021

Estuaries and Coasts

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Observations and modeling are used to assess potential impacts of sediment releases due to dam removals on the Hudson River estuary. Watershed sediment loads are calculated based on sediment-discharge rating curves for gauges covering 80% of the watershed area. The annual average sediment load to the estuary is 1.2 Mt, of which about 0.6 Mt comes from side tributaries. Sediment yield varies inversely with watershed area, with regional trends that are consistent with substrate erodibility. Geophysical and sedimentological surveys in seven subwatersheds of the Lower Hudson were conducted to estimate the mass and composition of sediment trapped behind dams. Impoundments were classified as (1) active sediment traps, (2) run-of-river sites not actively trapping sediment, and (3) dammed natural lakes and spring-fed ponds. Based on this categorization and impoundment attributes from a dam inventory database, the total mass of impounded sediment in the Lower Hudson watershed is estimated as 4.9 ± 1.9 Mt. This represents about 4 years of annual watershed supply, which is small compared with some individual dam removals and is not practically available given current dam removal rates. More than half of dams impound drainage areas less than 1 km2, and play little role in downstream sediment supply. In modeling of a simulated dam removal, suspended sediment in the estuary increases modestly near the source during discharge events, but otherwise effects on suspended sediment are minimal. Fine-grained sediment deposits broadly along the estuary and coarser sediment deposits near the source, with transport distance inversely related to settling velocity.

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Section: Estuarine Impacts Of Sediment From Dam Removalsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Watershed Suspended Sediment Supply and Potential Impacts of Dam Removals for an Estuary

Ralston

Yellen

Woodruff

2021

Estuaries and Coasts

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“…Our work also suggests that other factors which can contribute to variation in nocturnal illumination in the sea, including artificial light sources (e.g. overspill and/or cloud reflection from coastal cities [78][79][80]), suspended sediments [81], and/ or climate change that is predicted to alter geographical distributions of cloud cover [82][83][84], have the potential to disrupt marine ecosystems. Accounting for such effects may greatly improve forecasts that inform future management and conservation efforts.…”

Section: Discussionmentioning

confidence: 70%

Lunar rhythms in growth of larval fish

Shima

Osenberg

Noonburg³

et al. 2021

Proc. R. Soc. B.

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Growth and survival of larval fishes is highly variable and unpredictable. Our limited understanding of this variation constrains our ability to forecast population dynamics and effectively manage fisheries. Here we show that daily growth rates of a coral reef fish (the sixbar wrasse, Thalassoma hardwicke ) are strongly lunar-periodic and predicted by the timing of nocturnal brightness: growth was maximized when the first half of the night was dark and the second half of the night was bright. Cloud cover that obscured moonlight facilitated a ‘natural experiment’, and confirmed the effect of moonlight on growth. We suggest that lunar-periodic growth may be attributable to light-mediated suppression of diel vertical migrations of predators and prey. Accounting for such effects will improve our capacity to predict the future dynamics of marine populations, especially in response to climate-driven changes in nocturnal cloud cover and intensification of artificial light, which could lead to population declines by reducing larval survival and growth.

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“…Long-and short-term increases in flow can lead to changes to geomorphology from sediment erosion (#1 Figure 2; Park et al, 2014) and prolonged inundation of intertidal habitat (#2 Figure 2; Adams, 2020), both resulting in habitat loss. Elevated flow may transport more sediment, humic substances and dissolved organic matter (DOC, including chromophoric components) from catchments (#3 and #4 Figure 2) which act to reduce light availability (#5 Figure 2) to primary producers (Andersson et al, 2015;Glover et al, 2019). Excess sediment may impact benthic fauna through interference with filter feeding and smothering of larvae (#5 Figure 2; Huang et al, 2016).…”

Section: Increasing and Decreasing Flowsmentioning

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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Impacts of Suspended Sediment on Nearshore Benthic Light Availability Following Dam Removal in a Small Mountainous River: In Situ Observations and Statistical Modeling

Cited by 12 publications

References 53 publications

Watershed Suspended Sediment Supply and Potential Impacts of Dam Removals for an Estuary

Watershed Suspended Sediment Supply and Potential Impacts of Dam Removals for an Estuary

Lunar rhythms in growth of larval fish

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

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