Reply to ‘Wolf‐triggered trophic cascades and stream channel dynamics in Olympic National Park: a comment on East et al. (2017)’ by Robert Beschta and William Ripple          下载免费PDF全文

Amy E. East  Kurt J. Jenkins  Patricia J. Happe  Jennifer A. Bountry  Timothy J. Beechie  Mark C. Mastin  Joel B. Sankey  Timothy J. Randle 《地球表面变化过程与地形》2018,43(4):936-939

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Reconstruction of fluvio-lacustrine landscapes and settlement history in the Texcoco region,Mexico, using a modern geomorphic analog     

Kurt H. Wogau  Carlos E. Cordova  Luis Morett-Alatorre  Guillermo Acosta Ochoa 《Geoarchaeology》2024,39(2):168-182

Located in the Basin of Mexico, the eastern shore of former Lake Texcoco sustained a variety of human occupations throughout the Holocene, including preceramic hunter-gatherers, incipient agriculturalists, and a variety of settlements in the ceramic periods. Nonetheless, the environmental dynamics of occupations on the lakeshore have not been fully addressed. The Archaic preagricultural Texcoco Man site (>5000 B.C.E.) and the Late Formative TX-LF-14 site (c. 550-200 B.C.E.), among others, occupy this fluvio-lacustrine transitional environment. Few stratigraphic works in and around the sites have been performed. Consequently, it is difficult to understand the dynamics of the sedimentary system in space and time. This work highlights and describes the fluvio-lacustrine sedimentary dynamics and the resulting landscape that past societies inhabited on the eastern shore of Texcoco Lake. Because the study area has been altered by historic and modern draining, our work employs Lake Santiaguillo and its main tributary, the Tejamen River in the Durango state, as a modern analog to study their sedimentary dynamics. The analyses of surface geomorphology in the Texcoco study area were employed to corroborate the modern analog interpretation. To achieve these goals, we conducted a GIS-based morphometric analysis and LANDSAT-8 imagery to study the variations in landforms through wet and dry events. The results indicate an increase in the lake volume, low bifurcation in the active fluvial channels, few inundated surfaces, and the presence of bird-foot deltaic channels during high precipitation events. In contrast, low precipitation events are characterized by reduced lake volume, increased fluvial channel bifurcation, and expanded floodplains. This heterogeneous landscape thus provided a rich source of diverse natural resources of saline and freshwater aquatic habitats. Simultaneously, constant or recurring flooding events generated a challenging landscape for prehistoric settlers who implemented diverse technologies, such as the construction of tlateles, on the levees of deltaic channels to reduce the risk and impact of flooding events.  相似文献   

Deep-sea faunal communities associated with a lost intermodal shipping container in the Monterey Bay National Marine Sanctuary,CA     

Josi R. Taylor  Andrew P. DeVogelaere  Erica J. Burton  Oren Frey  Lonny Lundsten  Linda A. Kuhnz  P.J. Whaling  Christopher Lovera  Kurt R. Buck  James P. Barry 《Marine pollution bulletin》2014

Carrying assorted cargo and covered with paints of varying toxicity, lost intermodal containers may take centuries to degrade on the deep seafloor. In June 2004, scientists from Monterey Bay Aquarium Research Institute (MBARI) discovered a recently lost container during a Remotely Operated Vehicle (ROV) dive on a sediment-covered seabed at 1281 m depth in Monterey Bay National Marine Sanctuary (MBNMS). The site was revisited by ROV in March 2011. Analyses of sediment samples and high-definition video indicate that faunal assemblages on the container’s exterior and the seabed within 10 m of the container differed significantly from those up to 500 m. The container surface provides hard substratum for colonization by taxa typically found in rocky habitats. However, some key taxa that dominate rocky areas were absent or rare on the container, perhaps related to its potential toxicity or limited time for colonization and growth. Ecological effects appear to be restricted to the container surface and the benthos within ∼10 m.  相似文献   

Comment on Stadmark and Conley (2011) "Mussel farming as a nutrient reduction measure in the Baltic Sea: consideration of nutrient biogeochemical cycles"     

Rose JM  Ferreira JG  Stephenson K  Bricker SB  Tedesco M  Wikfors GH 《Marine pollution bulletin》2012,64(2):449-51; author reply 455-6

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Cladocora caespitosa bioconstructions in the Columbretes Islands Marine Reserve (Spain,NW Mediterranean): distribution,size structure and growth     

Diego‐Kurt Kersting  Cristina Linares 《Marine Ecology》2012,33(4):427-436

Today, living banks of the coral Cladocora caespitosa appear to be restricted to a few Mediterranean locations and are threatened by the escalating impacts affecting coastal areas. In this study the exceptional occurrence of the Mediterranean coral C. caespitosa in the Columbretes Islands Marine Reserve (NW Mediterranean, Spain) is characterised in terms of spatial distribution, cover area, colony size and growth rates. The coral colonies form beds and banks in rocky bottoms within a semi‐enclosed bay that offers both hydrodynamic protection and high water exchange. The spatial distribution of the C. caespitosa colonies, from 5 to 27 m depth, is highly aggregated, depending on sea‐floor morphology and showing up to 80% of substrate coverage. The annual corallite growth rates obtained through the alizarin red staining method and x‐ray image analysis are similar, and range between 2.55 ± 0.79 mm and 2.54 ± 0.81 mm, respectively. The exceptional nature of these bioconstructions is due to their cumulative cover area, which is comparable in size to the largest C. caespitosa bioconstructions described to date in Mljet National Park (Croatia, Adriatic Sea).  相似文献   

Flood effects on phosphorus immobilisation in a river water filled pit lake—Case study Lake Goitsche (Germany)     

Peter Herzsprung  Martin Schultze  Bertram Boehrer  Anja Duffek  Andrea Van der Veen  Kurt Friese 《Limnologica》2010,40(2):182-190

Between 1999 and 2002, a former open-cast mine was filled with river water forming the recent Lake Goitsche. During filling initially acid water was neutralised. Phosphorus (P) imported from Mulde River was nearly completely removed from the water column by co-precipitation with iron (Fe) and aluminium (Al) and deposited in the sediment.During extremely high waters of the Mulde River in 2002, a dike breach facilitated a second high import of P into Lake Goitsche with suspended and dissolved matter. The analysis of total phosphorus (TP), however, showed that P again had been eliminated from the water body a few months after the flood event. Sediment investigations before filling with river water, during filling, and after the flood event were used to analyse the process of P immobilisation in a lake with acid mine drainage history.The ratios of Fe to soluble reactive P (SRP) of sediment pore water were up to three orders of magnitudes higher than in natural lakes and can serve as an indicator for potential internal P loading from sediments. The SRP concentrations at the oxic/anoxic boundary were near or below the limit of quantification (< 0.2 μmol/L). Fe and manganese (Mn) redox cycling were responsible for hindering P dissolution from sediment to lake water.Finally it can be stated, that the risk of eutrophication for such a lake seems to be low.  相似文献   

Multivariate skew-t approach to the design of accumulation risk scenarios for the flooding hazard     

Tatiana Ghizzoni  Giorgio Roth  Roberto Rudari 《Advances in water resources》2010

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Enhancement of Seismic Data Processing and Interpretation of Fracture Zones on the Upper Part of Granitic Basement in Cuu Long Basin,Vietnam     

Mai Thanh Tan  Mai Thanh Ha  Kurt J. Marfurt  Nguyen Trung Hieu  Nguyen Thi My Hanh 《Acta Geophysica》2016,64(6):2214-2231

The fractured granite basement is the primary oil and gas reservoir in the Cuu Long Basin, Vietnam. Due to the complexity of this nonlayered unconventional target, combined with complicated fault and fracture systems, the seismic data quality near and within the basement section is very low. For this reason, it is important to apply improved seismic data processing workflows, filtering and migration techniques, as wells as attribute processing methods to enhance the imaging quality.Our studies show that applying different types of filters, including the f-k, Radon transform and Tau-P, improves signal to noise ratio, removing multiples, revealing basement’s top and its related fractured and fault zones. In addition, the application of multi-arrival-solution migration algorithms, such as Kirchhoff Migration and Controlled Beam Migration, provides improved imaging for identifying basement top and faults and fractures within the basement. Furthermore, the application of seismic attributes such as curvature, apparent dip, or energy gradient, is important in locating faults and fractures, whereas mapping of intensity and orientation of such structures assists the delineation of “sweet spots” and assists the planning of exploration.  相似文献   

Short-Term Effects of an Oil Spill on Marsh-Edge Fishes and Decapod Crustaceans     

Agatha-Marie F. Roth  Donald M. Baltz 《Estuaries and Coasts》2009,32(3):565-572

On 19 April 2005, an oil spill occurred in southeastern Louisiana’s Barataria Bay estuary. We used a drop sampler to characterize the marsh-edge nekton community. Thirty-six locations were sampled in pre- and post-spill time frames from March through May 2005. Before–after control–impact (BACI) analyses of the total number of individuals (fishes + decapod crustaceans), total fishes, and sensitive species found significant interactions between the temporal (before/after) and spatial (control/impact) treatments and indicated an effect of the oil spill. Nonparametric analyses detected varied faunal assemblages across temporal treatments, but were similar in species composition among spatial treatments. While the BACI analyses showed event effects, differences were not strongly detected in nonparametric analyses of community structure. Fish are mobile and left the spill area after the disturbance, whereas the less mobile but more numerous benthic decapod crustaceans remained. The overall community structure appears to be robust and quickly recovered from the localized spill event.  相似文献   

An integrated study of the hydrogeology of volcanic islands using helicopter borne transient electromagnetic: Application in the Galápagos Archipelago     

Esben Auken  Sophie Violette  Noémi d’Ozouville  Benoît Deffontaines  Kurt I. Sørensen  Andrea Viezzoli  Ghislain de Marsily 《Comptes Rendus Geoscience》2009,341(10-11):899-907

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