Earth Sciences Commons^™

First Ecological Characterization Of Whip Black Coral Assemblages (Hexacorallia: Antipatharia) In The Easter Island Ecoregion, Southeastern Pacific, Jan M. Tapia-Guerra, Cynthia M. Asorey, Erin E. Easton, Daniel Wagner, Matthias Gorny, Javier Sellanes

School of Earth, Environmental, & Marine Sciences Faculty Publications

One of the main priorities of marine scientific research is to provide practical information and guidance for biodiversity conservation and management. In this context, the identification of key and fragile habitat-forming species is particularly important. Despite their ecological importance, whip corals in the order Antipatharia remain poorly studied around the world, and especially in the South Pacific. During recent expeditions to explore mesophotic and deep benthic habitats around Rapa Nui (Easter Island), dense assemblages of whip black corals were observed in situ. We here report the first detailed description of the distribution and abundance of these black coral assemblages …

Exposure Of Predatory And Scavenging Birds To Anticoagulant Rodenticides In France: Exploration Of Data From French Surveillance Programs, Meg-Anne Moriceau, Sébastien Lefebvre, Isabelle Fourel, Etienne Benoit, Florence Buronfosse-Roque, Pascal Orabi, Barnett A. Rattner, Virginie Lattard

United States Geological Survey: Staff Publications

Wild raptors are widely used to assess exposure to different environmental contaminants, including anticoagulant rodenticides (ARs). ARs are used on a global scale for rodent control, and act by disruption of the vitamin K cycle that results in haemorrhage usually accompanied by death within days. Some ARs are highly persistent and bioaccumulative, which can cause significant exposure of non-target species.We characterized AR exposure in a heterogeneous sample of dead raptors collected over 12 years (2008–2019) in south-eastern France. Residue analysis of 156 liver samples through LC-MS/MS revealed that 50% (78/156) were positive for ARs, with 13.5% (21/156) having summed second-generation …

Ramon (Brosimun Alicastrum) Foliage As Supplement For Lactating Dual Purpose Cows, Carlos A. Sandoval-Castro, R. Cetina, I. Pérez, Luis Ramírez-Avilés

IGC Proceedings (1977-2023)

The objective of the present study was to asses the value of ramón (Brosimun alicastrum) foliage as a N-source in replacement of soybean-N in lactating dual purpose cows (Bos indicus x B. taurus). Four lactating cows were used in a latin rectangle design. Ramón was included to replace 0, 33, 66 and 100 % of the soybean-N contained in the supplement. Basal diet was fresh “Taiwán” a cultivar of Elephant grass (Pennisetum purpureum) fed ad libitum. Basal and total dry matter intake, digestibility (total fecal collection), saleable and calf suckled milk yields, and …

Dry Matter Yield, In Vitro Digestibility, Protein And Fiber Composition Of 'Tifton 9' Bahiagrass (Paspalum Notatum) At Six Maturities, J. M. B. Vendramini, C. M. Haddad, Carlos G. S. Pedreira

IGC Proceedings (1977-2023)

The objective of this research was to evaluate dry matter yield, in vitro digestibility, and the concentrations of protein and cell wall components in 'Tifton 9’clipped at six maturities. Herbage was cut at the age of 20, 27, 34, 41, 48 and 55 days. The experimental design was a randomized complete block with six trataments (ages) and four replications. Dry matter yield and acid detergent fiber ranged from 188 g m^-2, to 593 g m^-2 and 386.9 g kg^-1 to 375.1 g kg^-1 respectively, with the cubic regression model having the best fit (P< 0.05). Concentrations of crude protein decreased linearly (P< 0.05) from 121 to 69 g kg^-1. …

In Situ Degradability Of Hand Harvested Or Extrusa Samples Of Tanzania Grass (Panicum Maximum, Jacq.), T. T. Berchielli, A. K. D. Salman, R. N. Silveira, W. V. B. Soares, J. R. Nogueira, S. N. Kronka

IGC Proceedings (1977-2023)

In order to compare the in situ degradability of tanzania grass samples obtained as by extrusa or hand plucked, three ruminal fistulated cows were used in a completely randomized block design with split-plot scheme. Five grams of extrusa or hand harvested grasses were placed in nylon bags rumen incubated during 3, 6, 12, 24, 48, 96 and 120 hours. The degradability of DM, CP, NDF and ADF were, in this sequence, 62.59, 80.88, 50.73 and 46.65%, for hand harvested grass; and 79.53, 90.97, 71.21 and 65.68%, for extrusa. In situ degradability data of hand harvested samples were not reliable.

Herbivore Preference For Afternoon- And Morning-Cut Forages And Adoption Of Cutting Management Strategies, H. F. Mayland, J. C. Burns, D. S. Fisher, Glenn E. Shewmaker, R. Carlstrom, D. S. Cash

IGC Proceedings (1977-2023)

Photosynthesizing forage plants accumulate total nonstructural carbohydrates (TNC) during daylight, but then TNC concentrations are reduced during the night. Afternoon-cut forage (PM) has greater TNC value and thus economic value, than morning-cut (AM). Livestock prefer PM-cut hay and this can be readily demonstrated by offering animals a choice of hays cut in PM and AM. Alfalfa growers in the western United States are readily adopting PM-cutting technology to increase profits.

Near Infra-Red Measurement Of Nonstructural Carbohydrates In Alfalfa Hay, H. F. Mayland, J. C. Burns, D. S. Fisher, Glenn E. Shewmaker

IGC Proceedings (1977-2023)

Recently documented benefits from afternoon versus morning cut forage have encouraged laboratory reporting of total nonstructural carbohydrate (TNC) values as part of forage quality testing. Our objective was to determine if infra-red spectroscopy (NIRS), which is being used in many forage testing labs, could be reliably used to quantify forage sugars in hay samples. We used two alfalfa (Medicago sativa L.) sample populations that were analyzed by wet chemistry for sugars and scanned by NIRS. The first set consisted of field-dried hay samples that were oven dried at 70^oC and the second consisted of fresh, freeze-dried samples. …

Intake And Qualitative Aspects Of Guinea Grass Grazed By Sheep Over Three Different Seasons, Willem A. Van Niekerk

IGC Proceedings (1977-2023)

The objective of this study was to determine the influence of season on intake by sheep as well as certain selected qualitative characteristics of Panicum maximum (cv Gatton) (Guinea grass) at the mature growing stage. The lower DM content of the spring and summer grass (41.6 and 40.2%) did not hamper DOMI (48.1 and 26.7 W^0.75/d), respectively. The N concentration of the spring and summer grass was well within the limit required for optimal rumen microbial production (1.8 - 2.0%). The high cell wall components of the winter grass resulted most probably in a significant lower IVDOM value …

Identification And Quantification Of N-Alkanes In Three Tropical Grasses, T. C. M. Genro, Ê. R. Prates, L. R. L. De S. Thiago, M. Herrero, V. Sabatel

IGC Proceedings (1977-2023)

The main goal of this paper was to quantify the profile of n-alkanes in three tropical grasses. Hand plucking samples to simulate grazing were taking from Brachiaria brizantha cv. Marandu, Panicum maximum cv. Mombaça and Pennisetum purpureum cv. Cameroon. These samples were collected from an experiment established to assess intensive beef production from grasses throughout the year, under rotational grazing. Rotation order through the paddocks remained constant, with 30 days of rest after each grazing bout (16 paddocks, 2 days of grazing). Profiles of n-alkanes were analysed in three separate periods of the year: in the middle of the dry …

Determination Of N-Alkanes At Different Stratum Heights In A Pasture Of Panicum Maximum Cv. Mombaça, T. C. M. Genro, L. R. L. De S. Thiago, Ê. R. Prates, M. Herrero, V. Sabatel

IGC Proceedings (1977-2023)

The aim of this experiment was to determine n-alkane levels in the stem + leaf sheath and leaf blade components of a pasture of Panicum maximum cv. Mombaça, harvested in 20 cm stratified layers. This pasture was under rotational grazing for intensive beef production throughout the year. The grazing system was based on the use of 16 paddocks with a 2-day grazing period followed by a 30-day resting period. Profiles of n-alkanes were determined in samples harvested in three separate periods: in the middle of the dry season (August 97; PERIOD 1), at the beginning of the wet season (November …

Observation Of Bundle Sheath Digestion Of Panicum Maximum Jacq,, B. Lempp, Valéria P. B. Euclides, Maria Da Graça Morais, D. M. Victor

IGC Proceedings (1977-2023)

Cross-sections of available forage and extrusa fractions of leaf blades of Tanzânia-1, Mombaça and Massai grasses were evaluated for anatomic structure and observations of residue of in vitro digestibility. The observations showed greater frequency of scherenchyma girders in leaf blades of cv Massai, compared with order grasses. Tanzânia-1 and Mombaça residues were more susceptible to digestion, while Massai presented more frequently scherenchyma girders associated with less digestible bundle sheath.

A Simple Method For Estimating Alfalfa Fiber Content In The Field, Reuben M. Sulc, K. A. Albrecht, V. N. Owens

IGC Proceedings (1977-2023)

Predictive equations for alfalfa (Medicago sativa L.) quality (PEAQ) based on length of the longest stem and maturity stage of the most mature stem in a sample were developed and validated for estimating neutral detergent fiber (NDF) and acid detergent fiber (ADF) concentrations in alfalfa. The objective of this research was to validate PEAQ with a simplified maturity scale when estimating fiber content. Alfalfa samples varying in height and maturity were collected throughout the growing season from fields across six states in USA. Observed NDF and ADF values (determined via wet chemistry) were regressed on estimated values. The estimated …

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Research Sites Get Closer To Field Camps Over Time: Informing Environmental Management Through A Geospatial Analysis Of Science In The Mcmurdo Dry Valleys, Antarctica, Stephen M. Chignell, Madeline E. Myers, Adrian Howkins, Andrew Fountain

Geology Faculty Publications and Presentations

As in many parts of the world, the management of environmental science research in Antarctica relies on cost-benefit analysis of negative environmental impact versus positive scientific gain. Several studies have examined the environmental impact of Antarctic field camps, but very little work looks at how the placement of these camps influences scientific research. In this study, we integrate bibliometrics, geospatial analysis, and historical research to understand the relationship between field camp placement and scientific production in the McMurdo Dry Valleys of East Antarctica. Our analysis of the scientific corpus from 1907–2016 shows that, on average, research sites have become less …

Pre-Earthquake Ionospheric Perturbation Identification Using Cses Data Via Transfer Learning, Pan Xiong, Cheng Long, Huiyu Zhou, Roberto Battiston, Angelo De Santis, Dimitar Ouzounov, Xuemin Zhang, Xuhui Shen

Mathematics, Physics, and Computer Science Faculty Articles and Research

During the lithospheric buildup to an earthquake, complex physical changes occur within the earthquake hypocenter. Data pertaining to the changes in the ionosphere may be obtained by satellites, and the analysis of data anomalies can help identify earthquake precursors. In this paper, we present a deep-learning model, SeqNetQuake, that uses data from the first China Seismo-Electromagnetic Satellite (CSES) to identify ionospheric perturbations prior to earthquakes. SeqNetQuake achieves the best performance [F-measure (F1) = 0.6792 and Matthews correlation coefficient (MCC) = 0.427] when directly trained on the CSES dataset with a spatial window centered on the earthquake epicenter with the Dobrovolsky …

Effective Growing Degree Days As A Critical Factor For Yield And Qualitative Values Of Timothy In Subarctic Growing Conditions, Oiva Nissinen

IGC Proceedings (1977-2023)

The yield and forage quality of timothy (Phleum pratense L.) leys at different stages of development were studied in 1991-1999 at the Lapland Research Station of the Agricultural Research Centre of Finland in Rovaniemi (66^o35´N). The aim of the study was to determine the optimal time for the first cut with respect to yield and qualitative values. In timothy the first heads were visible on 25 June on average and full heading was seen on 5 July, i.e. some ten days later. During this period the dry matter yield increased from 2769 to 4945 kg/ha, crude protein …

Duration Of Regrowth Of Ryegrass (Lolium Perenne) Swards: Effects On Rumen Fermentation Of Lactating Dairy Cows, P. Chilibroste, S. Tamminga, H. Boer

IGC Proceedings (1977-2023)

The relative importance of duration of sward regrowth and rumen fill and fermentation on the control of grazing time and intake rate during the first grazing session of the day were studied. Four lactating dairy cows were allowed to graze ryegrass (Lolium perenne) swards, with five different regrowth periods after mowing (6, 9, 16, 22 and 30 d). The cows were allowed to graze until they stopped voluntarily. Samples of rumen liquid were taken at approximately 0, 30, 60, 120 and 240 min after the grazing session was finished. Concentration of volatile fatty acids (VFA) followed a significant …

Establishment Of Tanzania Grass Pasture Using Millet As A Companion Crop, José C. Pinto, M. C. Maia, I. F. De Andrade, I. P. A. Dos Santos, E. R. P. Bomfim, K. R. Soares

IGC Proceedings (1977-2023)

Forage yield and quality of millet [Pennisetum glaucum (L.) R. Br.] and tanzania grass (Panicum maximum Jacq. cv. Tanzania I) were evaluated when grown in mixture. The treatments evaluated were four seed mixture combinations, based on a standard sowing density of 8 kg.ha^-1, of tanzania grass/millet (08/00; 05/03; 04/04 and 03/05 kg.ha^-1) and three cutting frequencies (1 cutting – 100th day after sowing; 2 cuttings – 50th and 100th days after sowing and 3 cuttings – 40th, 70th and 100th days after sowing), in a randomized complete block design, with four replications, in a …

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Hydrological Feedbacks On Peatland Ch4 Emission Under Warming And Elevated Co2: A Modeling Study, Fenghui Yuan, Yihui Wang, Daniel M. Ricciuto, Xiaoying Shi, Fengming Yuan, Thomas Brehme, Scott Bridgham, Jason Keller, Jeffrey M. Warren, Natalie A. Griffiths, Stephen D. Sebestyen, Paul J. Hanson, Peter E. Thornton, Xiaofeng Xu

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Peatland carbon cycling is critical for the land–atmosphere exchange of greenhouse gases, particularly under changing environments. Warming and elevated atmospheric carbon dioxide (eCO₂) concentrations directly enhance peatland methane (CH₄) emission, and indirectly affect CH₄ processes by altering hydrological conditions. An ecosystem model ELM-SPRUCE, the land model of the E3SM model, was used to understand the hydrological feedback mechanisms on CH₄ emission in a temperate peatland under a warming gradient and eCO₂ treatments. We found that the water table level was a critical regulator of hydrological feedbacks that affect peatland CH₄ dynamics; the …

Evaluation And Utilization Of A Tall Fescue Germplasm Collection At Pergamino Inta, Argentina, B. S. Rosso, E. M. Pagano, P. Rimieri

IGC Proceedings (1977-2023)

One hundred and fifty four accessions of tall fescue (Festuca arundinacea Schreb.) representing different types grown around the world were evaluated at Pergamino Inta Experimental Station. A multivariate analysis was carried out to evaluate individual and group variations. Three principal components (PCs) explained 70 % of the variation. Cluster analysis (Ward method) allowed the identification of 7 groups of populations. Plants from the most promising populations were selected in order to form a new breeding gene pool. The main objective of this study is to develop a new cultivar with improved winter herbage yield. Selected genotypes were mostly of …

Effects Of Selection On Morphological Characteristics In Setaria Sphacelata (Schumach.) Moss, Liana Jank, Kenneth H. Quesenberry, P. Mislevy

IGC Proceedings (1977-2023)

Cattle production in Florida is limited by the lack of available warm-season forages adapted to the cool winters of the region. Setaria (S. sphacelata) has demonstrated green growth during cool conditions in subtropical climates around the world, and has the potential to fill this niche in cattle production in Florida. Four populations were selected in Gainesville and Ona, Florida: two cycles of selection for increased head number, one cycle for increased leaf width and one cycle for grazing tolerance. The objectives of this research were to compare these populations morphologically to determine changes due to selection. Selection for …

Volumetric Extrusive Rates Of Silicic Supereruptions From The Afro-Arabian Large Igneous Province, Jennifer E. Thines, Ingrid A. Ukstins, Corey Wall, Mark Schmitz

Geosciences Faculty Publications and Presentations

The main phase of silicic volcanism from the Afro-Arabian large igneous province preserves some of the largest volcanic eruptions on Earth, with six units totaling >8,600 km³ dense rock equivalent (DRE). The large volumes of rapidly emplaced individual eruptions present a case study for examining the tempo of voluminous silicic magma generation and emplacement. Here were report high-precision ²⁰⁶Pb/²³⁸U zircon ages and show that the largest sequentially dated eruptions occurred within 48 ± 34 kyr (29.755 ± 0.023 Ma to 29.707 ± 0.025 Ma), yielding the highest known long-term volumetric extrusive rate of silicic volcanism on …

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Assessing Mangrove Wetland Structure And Function Regulated By Environmental Gradients Under Climate Change And Increasing Human Impacts: A Modeling Approach, Xiaochen Zhao

LSU Doctoral Dissertations

Mangroves are blue-carbon-rich wetlands that can potentially contribute to climate change mitigation policies. However, mangroves are increasingly impacted by both natural and human disturbances worldwide that require restoration and rehabilitation programs to advance their conservation. Yet, there are major knowledge gaps in our understanding of how local resources (nutrients), regulators (e.g., salinity) and hydroperiod gradients interact in controlling mangrove role as carbon sink or source at different spatiotemporal scales under increasing disturbance frequency and climate change.

Here, I developed a mass-balance-based hydrology model to estimate soil porewater salinity (PWS) in riverine mangroves along the Shark River estuary (SRE), South Florida; …

Evaluation Of Leucaena Genotypes, F. B. Sousa, M. R. A. Araujo, J. A. Araujo Filho, J. Sousa Neto

IGC Proceedings (1977-2023)

The objectives of this study were to evaluate the leucaena (Leucaena leucocephala) performance and to select the best genotypes, based on yield,.stability parameters, and quality parameters. Annual leucaena yields were obtained by cuts over the rainy and dry seasons. A combined analysis of variance for yield, and quality parameters was performed. Also stability parameters and coeficients of determination were estimated. The combined ANOVA for edible dry matter yield and for acid detergent fiber, and digestibility revealed a significant difference for genotypes, environments, genotypes x environments, row spacings, cutting frequencies, and cutting heights, Six genotypes of leucaena were selected …

Genotype-Environment Interaction For Forage Yield Of Vetch (Vicia Sativa L.) In Mediterranean Environments, G. Pacucci, C. Troccoli

IGC Proceedings (1977-2023)

Genotype x environment (GE) interactions limit the effectiveness of selection when selection is based only on mean yields. The objective of this study was to evaluate the amount of GE interaction for vetch forage yield in some environments of Southern Italy, and to analyze some stability parameters that can be useful in the selection of genotypes adapted to Mediterranean environmental conditions. Eleven vetch genotypes were grown in a total of 16 environments in Southern Italy. The combined analysis of variance for forage yield showed that the environment, genotype and GE interaction terms were significant at 0.01 level, suggesting a broad …

Initial Biomass Production And Soluble Carbohydrate Partitioning Of Contrasting Elephantgrass Genotypes, L. P. Passos, M. C. Vidigal, R. S. Verneque

IGC Proceedings (1977-2023)

The initial growth and soluble carbohydrate (SC) partitioning were examined in the following classes of elephantgrass (Pennisetum purpureum Schum.) genotypes: Dwarf (Anão, Mott and Roxo); Cameroon (Cameroon, Cameroon Piracicaba and Vruckwona); Embrapa hybrids (CNPGL F27-5 and Pioneiro); Interspecific hybrids (Hexaploide 201, Mercker X 23-A and Napier X 23-A; Mercker (Mercker Comum, Mercker Pinda and Teresópolis); and Napier (E.C. Itapemirim, Mineiro and Napier). After a 60-day growing period, total, leaf, stem and root FW and DW and stem, stem base, leaf and root SC content were determined. Cameroon-class cultivars showed the highest leaf and stem DW and whole stem SC …

Evaluation Of Guineagrass (Panicum Maximum Jacq) Hybrids In Brazil, Liana Jank, Cacilda B. Do Valle, J. De Carvalho, S. Calixto

IGC Proceedings (1977-2023)

Guineagrass (Panicum maximum Jacq.) is responsible for a high percentage of cattle finishing and milk production in Brazil, but presents problems of pasture degradability due to high soil fertility requirements and uneven production distribution. In order to search for new varieties to reduce these problems, over four hundred apomictic accessions of guineagrass and several sexual plants were introduced to Brazil in 1982. Agronomic evaluation took place at the National Beef Cattle Research Center of the Brazilian Agricultural Research Corporation (Embrapa Beef Cattle), in Campo Grande, MS, Brazil. Breeding of the apomictic species began in 1990 using sexual x apomictic …

Effects Of Material Texture And Packing Density On The Interfacial Polarization Of Granular Soils, Hang Chen, Qifei Niu

Geosciences Faculty Publications and Presentations

Many electrical and electromagnetic (EM) methods operate at MHz frequencies, at which the interfacial polarization occurring at the solid-liquid interface in geologic materials may dominate the electrical signals. To correctly interpret electrical/EM measurements, it is therefore critical to understand how the interfacial polarization influences the effective electrical conductivity and permittivity spectra of geologic materials. We have used pore-scale simulation to study the role of material texture and packing in interfacial polarization in water-saturated granular soils. Synthetic samples with varying material textures and packing densities are prepared with the discrete element method. The effective electrical conductivity and permittivity spectra of these …