446 research outputs found
Monitoring fish populations in Lower Lough Erne, Northern Ireland: applicability of current methods and implications for future monitoring under the EC Water Framework Directive
The proposed EC Water Framework Directive (WFD) will require member states to monitor both biotic and abiotic components of lake environments. With adoption of the WFD some measurement of fish populations will also be required. This paper describes work carried out since 1971, and particularly since 1991, on the status of fish populations in Lower Lough Erne, Northern Ireland, with an emphasis on defining change over time due to human impacts on the lake. This offers a reasonable starting point from which to develop a monitoring programme suitable for the needs of the WFD in this lake. The implications for as yet unmonitored fish populations in lakes are also determined
CONSERVATION OF THE IRISH POPULATIONS OF THE POLLAN COREGONUS AUTUMNALIS
ABSTRACT The Irish lake populations of pollan Coregonus autumnalis Pallas are detached from other Arctic populations and exist at the southern extreme of the range of the species. They are landlocked relics of postglacial colonisation by anadromous forms. In Ireland, pollan exist in atypical habitats and temperature ranges for the species as a whole and are threatened with extinction by a range of potentially detrimental factors, including eutrophication and competition with introduced nonindigenous species. All but one of the four populations is critically endangered. This paper summarises current knowledge of pollan, the status of the four populations and actions proposed to protect and enhance the remaining stocks
Evidence for a great Mw>7 Pre-Hispanic (AD 1300-1400) Crustal Earthquake in the Forearc of Peru
Seismic hazard in South Peru is thought to be dominated by earthquakes on the subduction interface (e.g. Villegaz-Lanza et al., 2016). Little is known about other possible sources of major earthquakes, such as the ~300-km-long Incapuquio Fault System (IFS) outcropping in forearc, active during Cenozoic times (e.g. Jacay et al., 2002; Audin et al., 2006). It is seismically active, but no study deals with its actual potential activity and its seismic hazard. From fieldwork and high-resolution DEMs, we evidenced that the IFS is active with an inverse motion associated to a left-lateral component: the surface is displaced (up to 4.5 m vertical cumulative offset) with outcrops of free faces over ~100 km distance, recent fluvial terraces are overthrusted by Paleozoic rocks, rivers beds are bent, etc. Despite the hyper-arid environment, we found charcoals of roots killed by the earthquake located in the fault plane. Their 14C dating gives a cluster of ages around AD 1325. We interpret it as the last earthquake that occurred along this fault segment with an Mw>7 magnitude (0.7 m vertical, 1.2 m total). The timing of the Mw>7 earthquake coincides with the end of the Chiribayas civilization in Moquegua valley, which has previously been attributed to the âmega-Niñoâ Miraflores climatic catastrophe (1300-1350) that may have induced the collapse of the irrigation and thus agricultural system (e.g. Satterlee et al., 2000; Goldstein & Magilligan, 2011). This last hypothesis is discussed because in some places, no evidences of mega floods that may have destroyed the canals have been found (Clement & Moseley, 1991), and also because that it has been shown that these human civilization living in this hyper arid area adapted their agricultural system and subsistence to the El Niño climatic fluctuations (Zaro et al, 2013). We thus propose that this collapse could also be due to the ~AD 1325 Mw>7 earthquake on the IFS, or to the sum of the earthquake and the Miraflores climatic Catastrophe
Impact of a paleo-earthquake and debris flow in Pikillaqta collapse, Cusco-PerĂș
In Cusco Valley, have been highlighted the Tambomachay, Pachatusan and Cusco active faults (Cabrera, 1988 & Benavente et al., 2013). Cusco has a historical and instrumental seismic record Mw> 5, events occurred in 1650, 1950 and 1986 (Silgado, 1978, Tavera, 2002). In the same way, during pre-Inca and Inca periods, they suffered the occurrence of earthquakes, this is evidenced in myths and chronicles collected by different chroniclers in XVIth century. These records, however, are limited, due to poor instrumental seismic data. Thus, during our work on paleosismology and archaeoseismology studies in Cusco with the aim of complementing the seismic catalog, weâve visited several archaeological sites. Among the archaeological centers visited, we were more interested in the Pikillaqta Archaeological Park (PAP), a city that was built at Wari Empire time, a culture that developed in southern Peru between 600 and 1000 AD (Bergh, 2012). The interest of studying this site is basically due to its archaeological evidence of unjustified abandonment around 900 AD (McEwan, 2015). Subsequently, our archeoseismology studies, based on the identification of Earthquake Archeological Effects (Rodriguez-Pascua et al., 2011), and post-seismic effects like new architectural elements dated by 14C in 900 AD, allowed us to observe an important seismic event at this age. In PAP we observed alluvial deposits of up to 2m in height inside the rooms and halls, evidencing a debris flow. Drone images, allowed us to observe drainages related to the entrance of a flow at PAP east, generating an alluvial cone in the PAP main square. Works in situ, allowed us find pottery and bones within the mud flow, dated also around 900 AD. On the other hand, results of paleosismology in the Tambomachay fault (Rosell, 2018), show a seismic event around 900 AD. With the previously mentioned, exist a clear relationship between archaeoseismology and paleosismological results. The event occurred at the end of the 9th century, originating its attempt at reconstruction and subsequent abandonment
Long term abundance patterns of potamodromous brown trout in a large lacustrine catchment in County Fermanagh
Publication history: Accepted - 12 February 2021; Published online - 29 September 2021.Long-term survey data detailing brown trout abundance in the Lough Erne catchment in Co.
Fermanagh were tabulated from 1968â2016. These data included redd counts and electric fishing surveys across three key spawning tributaries in addition to gill-net surveys of the lake. The abundance
of spawning adults fluctuated widely across the time-series and were examined in relation to various
pressures, including a major disease epidemic and the invasion of the catchment by zebra mussels.
A functional stock-recruitment relationship between adult spawners and young-of-year juveniles
in the spawning tributaries was identified and described. Redd counts were significantly lower for
the post-zebra mussel time-series (2000â16) than the pre-zebra mussel time-series (1968â99). The
post-zebra mussel invasion period was associated with increased water clarity, reduced plankton productivity and changes to the balance of coarse fish species in the lake. The significance of these
changes is discussed in relation to the trout stock
Paleoseismic Evidence of an Mw 7 Pre-Hispanic Earthquake in the Peruvian Forearc
We present the results of a paleoseismic survey of the Incapuquio Fault System, a prominent transpressional fault system cutting the forearc of South PerĂș. High-resolution Digital Elevation Models, optical satellite imagery, radiocarbon dating, and paleoseismic trenching indicate that at least 2â3 m of net slip occurred on the Incapuquio Fault generating a complex, âŒ100-km long set of segmented fault scarps in the early 15th century (âŒ1400â1440 CE). We interpret the consistent along-strike pattern of fault scarp heights, geometries and kinematics to reflect a surface rupture generated by a single Mw 7.4â7.7 earthquake, suggesting that brittle failure of the forearc poses a significant, yet mostly overlooked, seismic hazard to the communities in coastal areas of PerĂș. The timing of this earthquake coincides with the collapse of the Chiribaya civilization in âŒ1360â1400 CE, and we present evidence of damaged buildings along the fault trace that may be of Chiribayas age. Our surface faulting observations, when combined with observations of deformation in the forearc from geodesy and seismology, also demonstrate that the forearc in South PerĂș experiences a complex, time-varying pattern of permanent strain, with evidence for trench-parallel shortening, trench-parallel extension, and trench-perpendicular shortening all in close proximity but in different periods of the megathrust earthquake cycle. The kinematics of recent slip on the Incapuquio Fault are consistent with the sense of interseismic strain within the forearc measured by GPS, suggesting the fault is loaded toward failure between megathrust earthquakes
Culturing of the first 37:4 predominant lacustrine haptophyte : geochemical, biochemical, and genetic implications
Author Posting. © The Author(s), 2011. This is the author's version of the work. It is posted here by permission of Elsevier B.V. for personal use, not for redistribution. The definitive version was published in Geochimica et Cosmochimica Acta 78 (2012): 51â64, doi:10.1016/j.gca.2011.11.024.Long chain alkenones (LCAs) are potential biomarkers for quantitative paleotemperature reconstructions from lacustrine environments. However, progress in this area has been severely hindered by the lack of culture studies of haptophytes responsible for alkenone distributions in lake sediments: the predominance of C37:4 LCA. Here we report the first enrichment culturing of a novel haptophyte phylotype (Hap-A) from Lake George, ND that produces predominantly C37:4-LCA. Hap-A was enriched from its resting phase collected from deep sediments rather than from water column samples. In contrast, enrichments from near surface water yielded a different haptophyte phylotype (Hap-B), closely related to Chrysotila lamellosa and Pseudoisochrysis paradoxa, which does not display C37:4-LCA predominance (similar enrichments have been reported previously). The LCA profile in sediments resembles that of Hap-A enrichments, suggesting that Hap-A is the dominant alkenone producer of the sedimentary LCAs. In enrichments, excess lighting appeared to be crucial for triggering blooms of Hap-A. Both and indices show a linear relationship with temperature for Hap-A in enrichments, but the relationship appears to be dependent on the growth stage. Based on 18S rRNA gene analyses, several lakes from the Northern Great Plains, as well as Pyramid Lake, NV and Tso Ur, Tibetan Plateau, China contain the same two haptophyte phylotypes. The Great Plains lakes show the Hap-A-type LCA distribution, whereas Pyramid and Tso Ur show the Hap-B type distribution. Waters of the Great Plain lakes are dominated by sulfate, whereas those Pyramid and Tso Ur are dominated by carbonate, suggesting that the sulfate to carbonate ratio may be a determining factor for the competitiveness of the Hap-A and Hap-B phylotypes in natural settings.This work was supported by a grant from the National Science Foundation to Y. Huang (EAR06-02325) and a Brown University Graduate School Dissertation Fellowship to J. L. Toney
Dataset on the evidence of bee products processing : a functional definition of a specialized type of macro-lithic tool
Unidad de excelencia MarĂa de Maeztu MdM-2015-0552The database includes spatial, chronological and technological information about the analyzed tools in the article entitled "Evidence of bee products processing: a functional definition of a specialized type of macro-lithic tool" (Ache et al., 2017 ). The technological information refers to the tool type, its rock type, weight, state of preservation, morphology, metrical data and functional features. We also provide an index of acronyms to properly understand the dataset published here
Recommended from our members
Looking beyond the exome: a phenotype-first approach to molecular diagnostic resolution in rare and undiagnosed diseases.
PurposeTo describe examples of missed pathogenic variants on whole-exome sequencing (WES) and the importance of deep phenotyping for further diagnostic testing.MethodsGuided by phenotypic information, three children with negative WES underwent targeted single-gene testing.ResultsIndividual 1 had a clinical diagnosis consistent with infantile systemic hyalinosis, although WES and a next-generation sequencing (NGS)-based ANTXR2 test were negative. Sanger sequencing of ANTXR2 revealed a homozygous single base pair insertion, previously missed by the WES variant caller software. Individual 2 had neurodevelopmental regression and cerebellar atrophy, with no diagnosis on WES. New clinical findings prompted Sanger sequencing and copy number testing of PLA2G6. A novel homozygous deletion of the noncoding exon 1 (not included in the WES capture kit) was detected, with extension into the promoter, confirming the clinical suspicion of infantile neuroaxonal dystrophy. Individual 3 had progressive ataxia, spasticity, and magnetic resonance image changes of vanishing white matter leukoencephalopathy. An NGS leukodystrophy gene panel and WES showed a heterozygous pathogenic variant in EIF2B5; no deletions/duplications were detected. Sanger sequencing of EIF2B5 showed a frameshift indel, probably missed owing to failure of alignment.ConclusionThese cases illustrate potential pitfalls of WES/NGS testing and the importance of phenotype-guided molecular testing in yielding diagnoses
Paleoseismic Evidence of an Mw 7 Pre-Hispanic Earthquake in the Peruvian Forearc
We present the results of a paleoseismic survey of the Incapuquio Fault System, a prominent transpressional fault system cutting the forearc of South PerĂș. High-resolution Digital Elevation Models, optical satellite imagery, radiocarbon dating, and paleoseismic trenching indicate that at least 2â3 m of net slip occurred on the Incapuquio Fault generating a complex, âŒ100-km long set of segmented fault scarps in the early 15th century (âŒ1400â1440 CE). We interpret the consistent along-strike pattern of fault scarp heights, geometries and kinematics to reflect a surface rupture generated by a single Mw 7.4â7.7 earthquake, suggesting that brittle failure of the forearc poses a significant, yet mostly overlooked, seismic hazard to the communities in coastal areas of PerĂș. The timing of this earthquake coincides with the collapse of the Chiribaya civilization in âŒ1360â1400 CE, and we present evidence of damaged buildings along the fault trace that may be of Chiribayas age. Our surface faulting observations, when combined with observations of deformation in the forearc from geodesy and seismology, also demonstrate that the forearc in South PerĂș experiences a complex, time-varying pattern of permanent strain, with evidence for trench-parallel shortening, trench-parallel extension, and trench-perpendicular shortening all in close proximity but in different periods of the megathrust earthquake cycle. The kinematics of recent slip on the Incapuquio Fault are consistent with the sense of interseismic strain within the forearc measured by GPS, suggesting the fault is loaded toward failure between megathrust earthquakes
- âŠ