Monitoring Cavefish Populations and Environmental Quality in Cave Springs Cave, Arkansas

Cave Springs Cave, Benton County, Arkansas, was monitored from October 1997 to June 1998 to determine the chemical and physical environmental quality and the status of the population of threatened Ozark cavefish, Amblyopsis rosae. The majority of the chemical parameters measured were indicative of adequate environmental quality in the Cave Springs Cave ecosystem. However, several significant problems were revealed. A trend analysis of known water quality studies of this cave complex suggests that many organic and inorganic chemicals have increased in concentration in the last 14 years. This ecologically sensitive water body did not meet Arkansas water quality regulations for fecal coliform densities, and copper, selenium, and lead concentrations exceeded limits for exposure to aquatic life. The geometric mean total coliform count for base flows was 500 MPN/100ml, and during the March storm event, coliform densities exceeded 20,000 MPN/100ml. When compared to the national primary drinking water regulations, this spring water exceeds the maximum contaminant levels (MCL) for turbidity, nitrite, total coliforms, and Escherichia coli, and approaches the MCL’s for copper and zinc. During the March storm event, Escherichia coli densities exceeded 5,000 MPN/100ml. During the June storm event, nitrite levels reached 2 mg/L, twice the MCL for national drinking water standards. Nitrite toxicity is known to cause severe anemia in fishes and damage their tissues. One semi-volatile organic, Di (2-ethylhexyl) phthalate (DEHP), was found in significant concentration (500 ug/kg) in resident crayfish tissue. DEHP is known to bioaccumulate in fish tissue, and cause reproductive damage and reduced fertility in fish. A visual survey was performed on January 25, 1998, and 106 cavefish were sighted. This survey indicated a 30% decline in the Cave Springs Cave population. A comparison of base-flow sampling results at two different locations -- upstream and downstream of bat rookeries -- indicates that the majority of coliform bacteria are not attributed to bat guano. These findings suggest that bacteria are being imported into the cave stream from the recharge zone. The high nitrite, total coliform, and E. coli counts suggest that septic system leakage or the land application of animal waste is involved. Continued water quality monitoring and surveys of the Ozark cavefish population are recommended. Future monitoring should focus on storm events and parameters that measure pollutants originating from the recharge zone and their effect on the cave ecosystem. As well, investigation into the nature of the pollutants from the recharge zone is suggested

The complex 3-D transition from continental crust to backarc magmatism and exhumed mantle in the Central Tyrrhenian basin

Geophysical data from the MEDOC experiment across the Northern Tyrrhenian backarc basin has mapped a failed rift during backarc extension of cratonic Variscan lithosphere. In contrast, data across the Central Tyrrhenian have revealed the presence of magmatic accretion followed by mantle exhumation after continental breakup. Here we analyse the MEDOC transect E–F, which extends from Sardinia to the Campania margin at 40.5°N, to define the distribution of geological domains in the transition from the complex Central Tyrrhenian to the extended continental crust of the Northern Tyrrhenian. The crust and uppermost mantle structure along this ∼400-km-long transect have been investigated based on wide-angle seismic data, gravity modelling and multichannel seismic reflection imaging. The P-wave tomographic model together with a P-wave-velocity-derived density model and the multichannel seismic images reveal seven different domains along this transect, in contrast to the simpler structure to the south and north. The stretched continental crust under Sardinia margin abuts the magmatic crust of Cornaglia Terrace, where accretion likely occurred during backarc extension. Eastwards, around Secchi seamount, a second segment of thinned continental crust (7–8 km) is observed. Two short segments of magmatically modified continental crust are separated by the ∼5-km-wide segment of the Vavilov basin possibly made of exhumed mantle rocks. The eastern segment of the 40.5°N transect E–F is characterized by continental crust extending from mainland Italy towards the Campania margin. Ground truthing and prior geophysical information obtained north and south of transect E–F was integrated in this study to map the spatial distribution of basement domains in the Central Tyrrhenian basin. The northward transition of crustal domains depicts a complex 3-D structure represented by abrupt spatial changes of magmatic and non-magmatic crustal domains. These observations imply rapid variations of magmatic activity difficult to reconcile with current models of extension of continental lithosphere essentially 2-D over long distances

Seismic structure of the Central Tyrrhenian basin: Geophysical constraints on the nature of the main crustal domains

In this work we investigate the crustal and tectonic structures of the Central Tyrrhenian back-arc basin combining refraction and wide-angle reflection seismic (WAS), gravity, and multichannel seismic (MCS) reflection data, acquired during the MEDOC (MEDiterráneo OCcidental)-2010 survey along a transect crossing the entire basin from Sardinia to Campania at 40°N. The results presented include a ~450 km long 2-D P wave velocity model, obtained by the traveltime inversion of the WAS data, a coincident density model, and a MCS poststack time-migrated profile. We interpret three basement domains with different petrological affinity along the transect based on the comparison of velocity and velocity-derived density models with existing compilations for continental crust, oceanic crust, and exhumed mantle. The first domain includes the continental crust of Sardinia and the conjugate Campania margin. In the Sardinia margin, extension has thinned the crust from ~20 km under the coastline to ~13 km ~60 km seaward. Similarly, the Campania margin is also affected by strong extensional deformation. The second domain, under the Cornaglia Terrace and its conjugate Campania Terrace, appears to be oceanic in nature. However, it shows differences with respect to the reference Atlantic oceanic crust and agrees with that generated in back-arc oceanic settings. The velocities-depth relationships and lack of Moho reflections in seismic records of the third domain (i.e., the Magnaghi and Vavilov basins) support a basement fundamentally made of mantle rocks. The large seamounts of the third domain (e.g., Vavilov) are underlain by 10–20 km wide, relatively low-velocity anomalies interpreted as magmatic bodies locally intruding the mantle

Photoinduced Vibrations Drive Ultrafast Structural Distortion in Lead Halide Perovskite

The success of organic–inorganic perovskites in optoelectronics is dictated by the complex interplay between various underlying microscopic phenomena. The structural dynamics of organic cations and the inorganic sublattice after photoexcitation are hypothesized to have a direct effect on the material properties, thereby affecting the overall device performance. Here, we use ultrafast heterodyne-detected two-dimensional (2D) electronic spectroscopy to reveal impulsively excited vibrational modes of methylammonium (MA) lead iodide perovskite, which drive the structural distortion after photoexcitation. Vibrational analysis of the measured data allows us to monitor the time-evolved librational motion of the MA cation along with the vibrational coherences of the inorganic sublattice. Wavelet analysis of the observed vibrational coherences reveals the coherent generation of the librational motion of the MA cation within ∼300 fs complemented with the coherent evolution of the inorganic skeletal motion. To rationalize this observation, we employed the configuration interaction singles (CIS), which support our experimental observations of the coherent generation of librational motions in the MA cation and highlight the importance of the anharmonic interaction between the MA cation and the inorganic sublattice. Moreover, our advanced theoretical calculations predict the transfer of the photoinduced vibrational coherence from the MA cation to the inorganic sublattice, leading to reorganization of the lattice to form a polaronic state with a long lifetime. Our study uncovers the interplay of the organic cation and inorganic sublattice during formation of the polaron, which may lead to novel design principles for the next generation of perovskite solar cell materials

Effect of Raw and Extruded Propionic Acid-Treated Field Beans on Energy and Crude Protein Digestibility (In-Vitro and In-Vivo), Growth and Carcass Quality in Grow-Finisher Pigs

The in-vitro ileal digestibility of dry matter (DM), organic matter (OM), and crude protein (CP) of field beans treated with propionic acid (trFB) and extruded trFB (exFB) was determined in experiment 1. The DE and dCP values of trFB and exFB were determined using the difference method in experiment 2. The effect of replacing SBM with trFB and exFB in grow-finisher diets on growth, carcass quality, apparent ileal digestibility (AiD), and total tract digestibility (ATTD) of DM, OM, gross energy (GE), and CP were investigated in experiment 3. In exp. 1, in-vitro digestibility of exFB compared to trFB was unchanged for DM (p = 0.12), increased for OM (p 0.05).info:eu-repo/semantics/publishedVersio

The Tyrrhenian Basin formation: from continental rifting to seafloor spreading, followed by mantle exhumation and late fissural volcanism

European Geosciences Union General Assembly 2014 (EGU2014), 27 april - 2 may 2014, Vienna, Austria.-- 1 pageWe present a new interpretation of the configuration of the geological domains and the processes of rifting forming the Tyrrhenian basin based on newly acquired geophysical data. The basin is not presently extending, but its crustal structure preserves information of the temporal evolution of rifting processes. We present P-wave velocity (Vp) models and seismic reflection images of data collected in a two-ship seismic experiment with Spanish R/V Sarmiento de Gamboa and the Italian R/V Urania carried out in spring 2010. We present five several-hundred-km-long wide-angle seismic (WAS) profiles crossing the entire basin at different transects and five Multichannel Seismic Reflection (MCS) profiles coincident with WAS profiles. The 5 transects provide the tectonic structure, the geometry of sedimentary deposits, and the Vp distribution of the crust and upper mantle. This information allows to interpret mechanisms of deformation, define the petrological nature and distribution of the geological domains, infer the importance and potential role of magmatism in the rifting process, and constrain the location of break up and the region of mantle exhumation. The basin has opened from north to south with different extension factors. The northern region stopped opening after a relatively low extension factors, but towards the south extension increased up to full crustal separation that produced first abundant magmatism and subsequently mantle exhumation in another region. Later fissural volcanism followed producing large volcanic ridges and tall seamounts. This sequence of events and the resulting configuration is in stark contrast with predictions based on conventional models of back-arc spreadingPeer Reviewe