Due to its high spatial resolution and excellent water penetration, coastal light detection and ranging (LiDAR) coupled with multispectral imaging (MSS) has great promise for resolving shoreline features in the Great Lakes. Previous investigations in Lake Superior documented a metal-rich ''halo'' around the Keweenaw Peninsula, related to past copper mining practices. Grand Traverse Bay on the Keweenaw Peninsula provides an excellent Great Lakes example of global mine discharges into coastal environments. For more than a century, waste rock migrating from shoreline tailings piles has moved along extensive stretches of coast, damming stream outlets, intercepting wetlands and recreational beaches, suppressing benthic invertebrate communities, and threatening critical fish breeding grounds. In the bay, the magnitude of the discarded wastes literally ''reset the shoreline'' and provided an intriguing field experiment in coastal erosion and spreading environmental effects. Employing a combination of historic aerial photography and LiDAR, we estimate the time course and mass of tailings eroded into the bay and the amount of copper that contributed to the metal-rich halo. We also quantify underwater tailings spread across benthic substrates by using MSS imagery on spectral reflectance differences between tailings and natural sediment types, plus a depth-correction algorithm (Lyzenga Method). We show that the coastal detail from LiDAR and MSS opens up numerous applications for ecological, ecosystem, and geological investigations.Light detection and ranging (LiDAR) is an airborne laser-ranging technique that acquires high-resolution elevation and bathymetric data (Ackermann 1999). The data are collected with aircraft-mounted lasers capable of recording elevation measurements at a rate of 10-200-kHz pulses s 21 for above-water topographic stretches and 1-10-kHz for coastal bathymetric surveys, with a maximum vertical precision of 15 cm (Crow et al. 2007). In coastal surveys, the aircraft travels over a water stretch at about 60 m s 21 , pulsing two varying laser beams toward earth through an opening in the plane's fuselage: a red wavelength (infrared) beam that is reflected by the water surface and a narrow, blue-green wavelength beam that penetrates the water surface and is reflected from the bottom surface. The LiDAR sensor records the time difference between the two signals to derive measurements of water depth.An infrared version of LiDAR is used in forest applications, principally for biomass surveys and profiling of canopies (Lefsky et al. 1999). More recently, attention has expanded to underwater marine and freshwater applications. Under ideal conditions in coastal waters, blue-green laser penetration allows detection of structures down to depths approximately three times greater than passive light reflection. LiDAR has penetrated to a recorded maximum of 35 m in oceanic environments (Guenther 2007). Applications of blue-green laser techniques to mapping underwater structures have recently expanded. Marine s...

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Freshwater ecosystems provide numerous services for communities worldwide, including irrigation, hydropower, and municipal water; however, the services provided by inland fisheries – nourishment, employment, and recreational opportunities – are often comparatively undervalued. We provide an independent estimate of global lake harvest to improve biological and socioeconomic assessments of inland fisheries. On the basis of satellite‐derived estimates of chlorophyll concentration from 80,012 globally distributed lakes, lake‐specific fishing effort based on human population, and output from a Bayesian hierarchical model, we estimated that the global lake fishery harvest in the year 2011 was 8.4 million tons (mt). Our calculations excluded harvests from highly productive rivers, wetlands, and very small lakes; therefore, the true cumulative global fishery harvest from all freshwater sources likely exceeded 11 mt as reported by the Food and Agriculture Organization of the United Nations (FAO). This putative underestimate by the FAO could diminish the perceived importance of inland fisheries and perpetuate decisions that adversely affect these fisheries and millions of people.

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Relationships between land use or land cover and embeddedness, a measure of fine sediment in spawning gravels, were examined at multiple scales across 54 streams in the Russian River Basin, California. The results suggest that coarse-scale measures of watershed land use can explain a large proportion of the variability in embeddedness and that the explanatory power of this relationship increases with watershed size. Agricultural and urban land uses and road density were positively associated with embeddedness, while the opposite was true for forest cover. The ability of land use and land cover to predict embeddedness varied among five zones of influence, with the greatest explanatory power occurring at the entire-watershed scale. Land use within a more restricted riparian corridor generally did not relate to embeddedness, suggesting that reach-scale riparian protection or restoration will have little influence on levels of fine sediment. The explanatory power of these models was greater when conducted among a subset of the largest watersheds (maximum r 2 = 0.73) than among the smallest watersheds (maximum r 2 = 0.46).Résumé : Nous avons examiné à plusieurs échelles les relations entre l'utilisation des terres et la couverture végétale, d'une part, et le colmatage du substrat, une mesure des sédiments fins dans les graviers de reproduction, d'autre part, dans 54 cours d'eau du bassin versant de la rivière Russian, Californie. Nos résultats indiquent que des évaluations de l'utilisation des terres dans le bassin versant à une échelle grossière peuvent expliquer une proportion importante de la variabilité du colmatage et que le pouvoir explicatif de cette relation augmente en fonction de la taille du bassin versant. Il y a une association positive entre les utilisations urbaine et agricole des terres et la densité des routes, d'une part, et le colmatage, d'autre part, alors que la relation est inverse dans le cas de la couverture forestière. Le potentiel de l'utilisation des terres et de la couverture végétale pour prédire le colmatage varie en fonction des cinq zones d'influence et le potentiel maximal se manifeste à l'échelle du bassin versant entier. Il n'y a pas généralement de corrélation entre l'utilisation des terres sur un corridor plus étroit le long des rives et le colmatage, ce qui laisse croire que la restauration ou la protection des rives au niveau de la section du cours d'eau aura peu d'influence sur les quantités de sédiments fins. Le pouvoir explicatif de ces modèles est plus grand lorsqu'il s'applique à un sous-ensemble des bassins versants les plus grands (r 2 maximal = 0,73) plutôt qu'aux plus petits bassins versants (r 2 maximal = 0,46).[Traduit par la Rédaction] Opperman et al. 2751

A new method was developed, evaluated, and applied to generate a global dataset of growing-season chlorophyll-a (chl) concentrations in 2011 for freshwater lakes. Chl observations from freshwater lakes are valuable for estimating lake productivity as well as assessing the role that these lakes play in carbon budgets. The standard 4 km NASA OceanColor L3 chlorophyll concentration products generated from MODIS and MERIS sensor data are not sufficiently representative of global chl values because these can only resolve larger lakes, which generally have lower chl concentrations than lakes of smaller surface area. Our new methodology utilizes the 300 m-resolution MERIS full-resolution full-swath (FRS) global dataset as input and does not rely on the land mask used to generate standard NASA products, which masks many lakes that are otherwise resolvable in MERIS imagery. The new method produced chl concentration values for 78,938 and 1,074 lakes in the northern and southern hemispheres, respectively. The mean chl for lakes visible in the MERIS composite was 19.2 ± 19.2, the median was 13.3, and the interquartile range was 3.90-28.6 mg m −3 . The accuracy of the MERIS-derived values was assessed by comparison with temporally nearcoincident and globally distributed in situ measurements from the literature (n = 185, RMSE = 9.39, R 2 = 0.72). This represents the first global-scale dataset of satellitederived chl estimates for medium to large lakes.