ICAR: endoscopic skull‐base surgery

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Climate-Mediated Changes to Linked Terrestrial and Marine Ecosystems across the Northeast Pacific Coastal Temperate Rainforest Margin

Coastal margins are important areas of materials flux that link terrestrial and marine ecosystems. Consequently, climate-mediated changes to coastal terrestrial ecosystems and hydrologic regimes have high potential to influence nearshore ocean chemistry and food web dynamics. Research from tightly coupled, high-flux coastal ecosystems can advance understanding of terrestrial–marine links and climate sensitivities more generally. In the present article, we use the northeast Pacific coastal temperate rainforest as a model system to evaluate such links. We focus on key above- and belowground production and hydrological transport processes that control the land-to-ocean flow of materials and their influence on nearshore marine ecosystems. We evaluate how these connections may be altered by global climate change and we identify knowledge gaps in our understanding of the source, transport, and fate of terrestrial materials along this coastal margin. Finally, we propose five priority research themes in this region that are relevant for understanding coastal ecosystem links more broadly.Ye

Resource use by five sympatric parrotfishes in the San Blas Archipelago, Panama

Resource use by five sympatric species of parrotfish was quantified in the San Blas Archipelago of the Republic of Panama from March to August 1987. Detailed observations of parrotfishes on patch reefs and surrounding seagrass beds showed that they partition resources with respect to habitat, food and size, but not time. Although parrotfishes shared resources, the proportions of each resource used differed significantly among species. Scarus iserti (Bloch) scraped filamentous microalgae that grew from eroded coral pavement on lower slopes of patch reefs and in 'halos,' the area of sparse vegetation surrounding reefs. Sparisoma viride (Bonnaterre) foraged on upper slopes of patch reefs where they mostly took bites from dead coral and associated algae. S. aurofrenatum (Cuvier and Valenciennes) had the broadest diet, which consisted mostly of seagrasses and macro- and microalgae that were attached to dead coral on lower reef slopes and in halos. Although S. chrysopterum (Bloch and Schneider) commonly occurred on patch reefs, it primarily foraged in seagrass beds that surround them. S. rubripinne (Cuvier and Valenciennes) was distributed most widely, ranging from seagrass beds to reef crests, where it took bites from seagrasses, dead coral and macroalgae. Juveniles of all species occurred on lower slopes or in halos where they scraped filamentous microalgae from coral pavement. As they matured, parrotfishes moved into other habitats changing access to different types of food. All of these parrotfishes fed throughout the daytime, and resource use did not differ between morning and afternoon

Resource utilization by five sympatric parrotfishes in the San Blas archipelago, Panama

Resource use by five sympatric species of parrotfish was quantified in the San Blas Archipelago of the Republic of Panama from March to August 1987. Detailed observations of parrotfishes on patch reefs and surrounding seagrass beds showed that they partition resources with respect to habitat, food and size, but not time. Although parrotfishes shared resources, the proportions of each resource used differed significantly among species. Scarus iserti (Bloch) scraped filamentous microalgae that grew from eroded coral pavement on lower slopes of patch reefs and in 'halos,' the area of sparse vegetation surrounding reefs. Sparisoma viride (Bonnaterre) foraged on upper slopes of patch reefs where they mostly took bites from dead coral and associated algae. S. aurofrenatum (Cuvier and Valenciennes) had the broadest diet, which consisted mostly of seagrasses and macro- and microalgae that were attached to dead coral on lower reef slopes and in halos. Although S. chrysopterum (Bloch and Schneider) commonly occurred on patch reefs, it primarily foraged in seagrass beds that surround them. S. rubripinne (Cuvier and Valenciennes) was distributed most widely, ranging from seagrass beds to reef crests, where it took bites from seagrasses, dead coral and macroalgae. Juveniles of all species occurred on lower slopes or in halos where they scraped filamentous microalgae from coral pavement. As they matured, parrotfishes moved into other habitats changing access to different types of food. All of these parrotfishes fed throughout the daytime, and resource use did not differ between morning and afternoon

Weak synchrony in the timing of larval release in upwelling regimes

Intertidal crabs in diverse habitats worldwide release larvae synchronously during nocturnal spring high tides. This expedites seaward transport of the larvae to beyond high density areas of predatory fishes under the cover of darkness. We found that 4 species of intertidal crabs along the west coast of the USA shared this reproductive timing pattern. As in other mixed semidiurnal tidal regimes, biweekly patterns of larval release were more closely synchronized with the tidal amplitude cycle than the lunar cycle, and some crabs released larvae in daylight. However, unlike other places in the world, larval release was weakly synchronized to environmental cycles regardless of interspecific differences in vertical distributions on the shore. We provide evidence that weak synchrony in the timing of larval release in upwelling regimes can result from exposure to environmental variation over long incubation periods of externally brooded embryos. According to the prevailing paradigm, weaker synchrony in the timing of larval release will increase predation by planktivorous fishes in upwelling regimes. Weak synchrony in the timing of larval release should increase larval mortality in a wide array of animals that brood embryos in the intertidal zone, regardless of the selective force operating, and it could contribute to recruitment limitation in upwelling regimes. © Inter-Research 2011

Limited recruitment during relaxation events: Larval advection and behavior in an upwelling system

We capitalized on a long-term record of larval recruitment and a distinctive oceanographic signature to reveal how changes in ocean conditions affect larval advection, behavior, and recruitment in a region of strong, persistent upwelling and recruitment limitation. We repeatedly sampled the vertical and horizontal distribution of a larval assemblage and ocean conditions during infrequent relaxations of prevailing upwelling winds near Bodega Bay, California. During prolonged relaxation events, a poleward, coastal, boundary current imported low-salinity surface waters that were devoid of larvae to the study area. The resident larval assemblage was restricted to cold, saline, bottom waters and pushed offshore while diel vertical migrations were suppressed. Hence, changes in oceanographic conditions strongly affected behaviorally mediated larval distributions, revealing the reason that few species recruit during relaxation events in this region. During relaxation events in upwelling regions, poleward coastal boundary currents will force larvae offshore throughout the water column at small headlands and in seaward-flowing bottom currents at straight coastlines, but recruitment may decrease markedly only near estuaries where few larvae will arrive in low-salinity surface waters. Targeted profiling of larval assemblages complements widespread monitoring of recruitment from shore and is necessary to determine how changing ocean conditions affect larval distributions, recruitment dynamics, and the connectivity of populations. © 2012, by the Association for the Sciences of Limnology and Oceanography, Inc

Limited recruitment during relaxation events: Larval advection and behavior in an upwelling system

We capitalized on a long-term record of larval recruitment and a distinctive oceanographic signature to reveal how changes in ocean conditions affect larval advection, behavior, and recruitment in a region of strong, persistent upwelling and recruitment limitation. We repeatedly sampled the vertical and horizontal distribution of a larval assemblage and ocean conditions during infrequent relaxations of prevailing upwelling winds near Bodega Bay, California. During prolonged relaxation events, a poleward, coastal, boundary current imported low-salinity surface waters that were devoid of larvae to the study area. The resident larval assemblage was restricted to cold, saline, bottom waters and pushed offshore while diel vertical migrations were suppressed. Hence, changes in oceanographic conditions strongly affected behaviorally mediated larval distributions, revealing the reason that few species recruit during relaxation events in this region. During relaxation events in upwelling regions, poleward coastal boundary currents will force larvae offshore throughout the water column at small headlands and in seaward-flowing bottom currents at straight coastlines, but recruitment may decrease markedly only near estuaries where few larvae will arrive in low-salinity surface waters. Targeted profiling of larval assemblages complements widespread monitoring of recruitment from shore and is necessary to determine how changing ocean conditions affect larval distributions, recruitment dynamics, and the connectivity of populations. © 2012, by the Association for the Sciences of Limnology and Oceanography, Inc

Repeated eye reduction events reveal multiple pathways to degeneration in a family of marine snails

Eye reduction occurs in many troglobitic, fossorial, and deep‐sea animals but there is no clear consensus on its evolutionary mechanism. Given the highly conserved and pleiotropic nature of many genes instrumental to eye development, degeneration might be expected to follow consistent evolutionary trajectories in closely related animals. We tested this in a comparative study of ocular anatomy in solariellid snails from deep and shallow marine habitats using morphological, histological, and tomographic techniques, contextualized phylogenetically. Of 67 species studied, 15 lack retinal pigmentation and at least seven have eyes enveloped by surrounding epithelium. Independent instances of reduction follow numerous different morphological trajectories. We estimate eye loss has evolved at least seven times within Solariellidae, in at least three different ways: characters such as pigmentation loss, obstruction of eye aperture, and “lens” degeneration can occur in any order. In one instance, two morphologically distinct reduction pathways appear within a single genus, Bathymophila. Even amongst closely related animals living at similar depths and presumably with similar selective pressures, the processes leading to eye loss have more evolutionary plasticity than previously realized. Although there is selective pressure driving eye reduction, it is clearly not morphologically or developmentally constrained as has been suggested by previous studies

Transport of Crustacean Larvae Between a Low-Inflow Estuary and Coastal Waters

The effectiveness of larval behavior in regulating transport between well-mixed, low-inflow estuaries and coastal waters in seasonally arid climates is poorly known. We determined the flux of an assemblage of benthic crustacean larvae relative to physical conditions between a shallow estuary and coastal waters on the upwelling coast of northern California (38°18′N, 123°03′W) from 29 to 31 March 2006. We detected larval behaviors that regulate transport in adjacent coastal waters and other estuaries for only two taxa in the low-inflow estuary, but they were apparent for taxa outside the estuary. Vertical mixing in the shallow estuary may have overwhelmed larvae of some species, or salinity fluctuations may have been too slight to cue tidal vertical migrations. Nevertheless, all larval stages of species that complete development in nearshore coastal waters were present in the estuary, because they remained low in the water column reducing seaward advection or they were readily exchanged between the estuary and open coast by tidal flows. Weak tidal flows and gravitational circulation at the head of the estuary reduced seaward transport during development for species that completed development nearshore, whereas larval release during nocturnal ebb tides enhanced seaward transport for species that develop offshore. Thus, nonselective tidal processes dominated larval transport for most species back and forth between the low-inflow estuary and open coastal waters, whereas in adjacent open coastal waters, larval behavior in the presence of wind-induced shear was more important in regulating migrations between adult and larval habitats along this upwelling coast. © 2014 Coastal and Estuarine Research Federation