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Throughout the world, much food produced is wasted. The resource impact of producing wasted food is substantial; however, little is known about the energy and water consumed in managing food waste after it has been disposed. Herein, we characterize food waste within the Food-Energy-Water (FEW) nexus and parse the differential FEW effects of producing uneaten food and managing food loss and waste. We find that various food waste management options, such as waste prevention, landfilling, composting, anaerobic digestion, and incineration, present variable pathways for FEW impacts and opportunities. Furthermore, comprehensive sustainable management of food waste will involve varied mechanisms and actors at multiple levels of governance and at the level of individual consumers. To address the complex food waste problem, we therefore propose a “food-waste-systems” approach to optimize resources within the FEW nexus. Such a framework may be applied to devise strategies that, for instance, minimize the amount of edible food that is wasted, foster efficient use of energy and water in the food production process, and simultaneously reduce pollution externalities and create opportunities from recycled energy and nutrients. Characterization of FEW nexus impacts of wasted food, including descriptions of dynamic feedback behaviors, presents a significant research gap and a priority for future work. Large-scale decision making requires more complete understanding of food waste and its management within the FEW nexus, particularly regarding post-disposal impacts related to water. [ABSTRACT FROM AUTHOR]

The ecological benefits of healthy oyster populations have led to mounting interest in restoration of degraded reef habitats and design of nature-based reef features. However, hydrodynamic studies of restored oyster reef remain sparse, and little is known about changes in mean flow and turbulence as a function of time since restoration. In this study, we investigate hydrodynamic differences between restored (restoration age: <1 y, 2 y, 4 y), degraded, and intact intertidal oyster reefs in a shallow, microtidal estuary. Field experiments conducted at each reef were designed to characterize variability in flow and turbulence associated with differences in reef morphology and restoration age, addressing research questions of whether and when hydrodynamic function is reestablished following restoration. Minor differences in normalized turbulence parameters within the canopies of restored and reference reefs (2 cm above bottom) were associated with variable channel-to-reef velocity attenuation, which was linked to heterogeneity in oyster canopy structure as characterized by high-resolution laser scans. Within-canopy turbulence characteristics and normalized Reynolds stresses were significantly elevated on restored and reference reefs compared to the degraded reef, emphasizing the role of reef restoration in changing near-bed hydrodynamics. Above-canopy (9 cmab) turbulence was hydrodynamically similar across live reference and restored reefs of all restoration ages, with estimated roughness heights that scaled with the canopy height. Comparisons between intact and restored reefs indicate that properly restored reefs can reach hydrodynamic similarity with historically intact reefs within 1 year of restoration, a conclusion that supports the use of reef restoration as a tool to reestablish hydrodynamic functions on degraded reefs. [ABSTRACT FROM AUTHOR]

Highlights: [•] Summer stream temperatures changed following clearcut harvesting. [•] Changes in canopy cover were slight due to logging slash deposited over streams. [•] There was a variable response in maximum temperature changes among streams. [•] Minimum temperatures were lower in all streams, perhaps due to increased baseflows. [•] We observe no cumulative effect to stream temperatures at the watershed outlet. [Copyright &y& Elsevier]

Stabilization of eroding estuarine shorelines using living shoreline techniques, including native vegetation and nearshore structural components, has the potential to combat erosion while increasing shoreline ecotone function. However, there are few detailed field studies and little quantitative data available to assess hydrodynamic changes that occur immediately following living shoreline implementation. To address this gap, detailed hydrodynamic observations were made along eroding and stable reference shorelines over a 16-month period spanning living shoreline stabilization, which included the landfall of a major hurricane (Irma) 9 weeks after stabilization. In the months following stabilization, planted vegetation was sparse and shoreline hydrodynamics were governed by water level relative to breakwater structures. When water levels were at or below breakwater crest elevation, current velocities were initially reduced by 62% and wave heights by up to 83%; however, at higher water levels, shoreline velocities at the stabilized site vastly exceeded those observed at a nearby bare control site. Sixteen months after stabilization, flow-vegetation interactions had become a dominant control over shoreline hydrodynamics, and current attenuation was similar to that observed in nearby mature mangrove vegetation. Additionally, turbulence dissipation rates at the stabilized site (2.2∙10−5 m2/s3) and vegetated reference site (1.1∙10−5 m2/s3) were an order of magnitude greater during boat wake events compared to the bare shoreline site (1.6∙10−6 m2/s3, p < 0.001). This first experimental assessment of hydrodynamic effects related to living shoreline stabilization indicates that more than one year may be required before planted vegetation meaningfully influences shoreline hydrodynamics. [ABSTRACT FROM AUTHOR]

Oysters are ecosystem engineers that form reefs with rough surfaces. The complex surface of a reference-condition reef contains clusters of live oysters that protrude into and interact with flows. A degraded oyster reef contains fewer live oyster clusters and subsequently has different bed roughness. Such morphological differences may translate to varied hydrodynamic function, with influence to local and larger-scale flow fields and sediment transport, as well as larval recruitment and long-term reef sustainability. The objective of this study is to compare a degraded and a reference-condition intertidal oyster reef, and assess how differences in structure (reef morphology and roughness) influence near-bed hydrodynamic function within the roughness sublayer defined by oysters. Sediment entrainment and bed deformation were observed only on the reference oyster reef, despite that mean velocities were lower than those at the degraded reef. This was attributed to slightly finer bed material and higher turbulent kinetic energy, k , at the reference reef (k = 29.2 ± 4.5 cm2/s2 with mean velocity 11.5 ± 0.6 cm/s at 1 cm above the bed) compared to the degraded reef (k = 22.6 ± 4.2 cm2/s2 with mean velocity 16.1 ± 1.7 cm/s at 1 cm above the bed). At 1 cm above the bed, shear turbulence production at the degraded reef was significantly larger than turbulence dissipation rate, while at the reference reef this pattern was observed only for time periods with low turbulent kinetic energy. For measurements 5 cm above the bed at the reference reef, shear turbulence production and turbulence dissipation rates exhibited a relatively balanced pattern, with dissipation exceeding shear production for the time period with elevated turbulence. Four bed shear stress calculation methodologies converged over the degraded oyster reef but deviated considerably at the reference oyster reef. The drag coefficient associated with bed shear stress at the reference reef was almost two times greater than that at the degraded reef and almost an order of magnitude greater than those observed at sand and mud beds. [ABSTRACT FROM AUTHOR]