bluuebunny/crossref_metadata_2025 huggingface dataset:
Tasmanian coastal saltmarsh community transitions associated with climate change and relative sea level rise 1975 - 2009
Authors: Prahalad Vishnu N. , Kirkpatrick Jamie B. , Mount Richard E.
Published: November 2018

Coastal saltmarshes are reputed to be one of the most vulnerable communities to global warming, with widespread evidence of retreat and movement of lower marsh vegetation into areas previously occupied by upper marsh vegetation in response to rising sea levels, and potential changes in community composition from changes in rainfall, temperature and wind. We undertook an investigation of decades scale change in the distributions of saltmarsh communities defined by dominant species, using historic vegetation maps, remote sensing imagery and extensive field data collection. Our study area in south-eastern Tasmania has suffered a marked increase in temperatures and wind speeds and a marked decrease in rainfall since 1975, with sea level rising at a rate of 0.8 mm per annum. We therefore tested the hypothesis that these changes would result in a shift in saltmarsh community composition towards more salt- and inundation-tolerant communities and salt scalds. Eighteen percent of the 1975 marsh was lost to direct human modification and a net 4% was lost to coastal retreat. One large marsh was cut off from the sea then burned, then reconnected with the sea. The vegetation change between 1975 and 2009 in other parts of the saltmarshes occurred in 21% of their 1975 area. Most of the community transitions were consistent with increasing aridity. Thus, our results indicate that global warming has already caused marked changes in community composition in saltmarsh in Tasmania.
Vegetation and environmental relations of ephemeral subtropical wetlands in central Queensland, Australia
Authors: Halford J. J. , Fensham R. J.
Published: November 2018

An extensive network of ephemeral wetlands exists within arid and semiarid Australia. These wetlands provide important resources to local and migratory species; however, they are poorly studied, particularly in terms of their vegetation–environmental relations. To better understand these relationships, a flora survey was conducted in a large complex of ephemeral, subtropical wetlands in central Queensland, in an attempt to describe the vegetation patterns present, and determine their underlying environmental conditions. In total, eight vegetation groups were identified, with water depth having the greatest influence over vegetation patterns, with slope, assumed to affect drainage, having a secondary influence. Aquatics, such as Nymphaea gigantea Hook. and Vallisneria nana R.Br., characterise the deepest zone, grasslands and sedgelands characterise intermediate depths and a herbfield including many ephemeral terrestrial species characterises the shallow zone. The geography of the wetland-dependant species indicates mostly tropical affinities. All wetland-dependant species present are broadly distributed, with none requiring special conservation considerations. There are no significant infestations of exotic species, including ponded pasture species, that have spread throughout other tropical and subtropical wetlands. The complex of wetlands extending over a large catchment area in the upper Dawson River catchment is in excellent natural condition, and as such, it forms a very important component of the network of wetlands extending along the east coast of Australia.
What makes a swamp swampy? Water regime and the botany of endangered wetlands in western Victoria
Authors: Casanova Michelle T. , Powling I. Joan
Published: November 2018

Freshwater temporary wetlands are a little-studied ecosystem worldwide. They have been recognised as critically endangered in south-eastern Australia under Australian biodiversity conservation legislation. However, little has been recorded about their hydrology, functioning or biodiversity values; i.e. the factors that make them intrinsically ‘swampy’. In this paper, we developed a simple threshold model of wetland hydrology based on historical rainfall records and calculated evaporation records matched to records and recollections of the owners of swamps, and documented water-plant and microalgal species richness. The model indicated that swamps were inundated to at least 10-cm depth in an average of 6.3 years per decade for most of the 20th century. The average dry time between inundations was 1.27 years (maximum of 4.5 years). Since 1998, the frequency of inundation appears to have decreased, and the average dry times have increased. Despite, or because of, their temporary nature, these swamps have high biodiversity values among the vegetation and the microalgae, more than has been recorded for near-by permanent wetlands. There is no evidence that a drier and warmer climate will have a negative impact on biodiversity values; however, land management is likely to be important for maintaining these systems as the climate changes.
Fire regimes and interval-sensitive vegetation in semiarid Gregory National Park, northern Australia
Authors: Russell-Smith Jeremy , Yates Cameron P. , Brock Chris , Westcott Vanessa C.
Published: November 2018

Few data are available concerning contemporary fire regimes and the responses of fire interval-sensitive vegetation types in semiarid woodland savanna landscapes of northern Australia. For a 10 300 km2 semiarid portion of Gregory National Park, in the present paper we describe (1) components of the contemporary fire regime for 1998–2008, on the basis of assessments derived from Landsat and MODIS imagery, (2) for the same period, the population dynamics, and characteristic fine-fuel loads associated with Acacia shirleyi Maiden (lancewood), an obligate seeder tree species occurring in dense monodominant stands, and (3) the fire responses of woody species, and fine-fuel dynamics, sampled in 41 plots comprising shrubby open-woodland over spinifex hummock grassland. While rain-year (July–June) rainfall was consistently reliable over the study period, annual fire extent fluctuated markedly, with an average of 29% being fire affected, mostly in the latter part of the year under relatively harsh fire-climate conditions. Collectively, such conditions facilitated short fire-return intervals, with 30% of the study area experiencing a repeat fire within 1 year, and 80% experiencing a repeat fire within 3 years. Fine fuels associated with the interior of lancewood thickets were characteristically small (<1 t ha–1). Fine fuels dominated by spinifex (Triodia spp.) were found to accumulate at rates equivalent to those observed under higher-rainfall conditions. Stand boundaries of A. shirleyi faired poorly under prevailing fire regimes over the study period; in 16 plots, juvenile density declined 62%, and adult stem density and basal area declined by 53% and 40%, respectively. Although the maturation (primary juvenile) period of A. shirleyi is incompletely known, assembled growth rate and phenology data indicated that it is typically >10 years. Of 133 woody species sampled, all trees (n = 26), with the exception of A. shirleyi, were resprouters, and 58% of all shrub species (n = 105) were obligate seeders, with observed primary juvenile periods <5 years. Assembled data generally supported observations made from other northern Australian studies concerning the responses of fire-sensitive woody taxa in rugged, sandstone-derived landscapes, and illustrated the enormous challenges facing ecologically sustainable fire management in such settings. Contemporary fire regimes of Gregory National Park are not ecologically sustainable.
Effect of the Kerogen Molecular Structure on the Formation of Methane During Kerogen Pyrolysis
Authors: Wang Qing , Wang Xinmin , Pan Shuo
Published: November 2018

In this study, density functional theory (DFT) at the GGA/RPBE level was employed to examine the effects of the kerogen microstructure on the formation mechanism of methane during the pyrolysis of kerogen. The calculations prove that the evolution of CH4 during kerogen pyrolysis corresponds to demethylation, and the process of forming methane involves the interaction of intramolecular hydrogen atom transfer and assistant hydrogen atom transfer. In all reaction paths, the energy barrier of path 5 is the smallest at 260.56 kJ mol−1. The energy barrier of path 6 is the largest at 554.36 kJ mol−1. The results indicate that CO is favourable for demethylation, and CO2 is not conducive to demethylation. Path 1 is the formation of methane by the transfer of assistant hydrogen atoms, and the required energy barrier is 379.45 kJ mol−1. The side chain structure of the aromatic hydrocarbon structure is liable to demethylation to form methane. A comparison of the reaction energy barriers follows the order: path 1 < path 15 < path 14 < path 10, which indicates the that difference in the demethylation reaction is based on the microstructure. In the same reaction process, the benzene ring and the aliphatic hydrocarbon structure are more susceptible to demethylation to form methane. In the heterocyclic bicyclic structures containing O and S, a comparison of the reaction energy barriers follows the order: path 11 ≈ path 12 < path 13, so paths 11 and 12 are close, but path 13 is more difficult to occur, indicating that it is more difficult to demethylate with heteroatoms in the same ring. From a thermodynamic point of view, in the process of assisting the formation of methane by hydrogen atoms, the demethylation reaction is mainly an endothermic reaction. During the transfer of intramolecular hydrogen atoms, the demethylation reaction is mainly an exothermic reaction, and most reactions are spontaneous.
Phylogeography and species delimitation in the New Zealand endemic, genetically hypervariable harvestman species, Aoraki denticulata (Arachnida, Opiliones, Cyphophthalmi)
Authors: Fernández Rosa , Giribet Gonzalo
Published: November 2018

Aoraki denticulata, a widespread mite harvestman endemic to the NW South Island of New Zealand, was postulated to constitute an old lineage with deep genetic history. Expanding on previous studies, we explored its genetic diversity and population structure, phylogeography and diversification patterns. We also examined the systematic implications of such a complex scenario through species delimitation analyses under coalescent-based and barcoding gap discovery methodologies. Our results depict the deep evolutionary history of the A. denticulata lineage, which shows high geographic structure and low genetic connectivity among modern populations. Aoraki denticulata is further subdivided into three lineages: a lineage presently inhabiting the northern region of the Southern Alps (and including the subspecies A. d. major), a second lineage in the north-eastern part of the sampled land, and a third one occupying the south-eastern localities. When using species delimitation methods based on coalescence approaches, large numbers of cryptic species were estimated. Based on morphological and biological evidence, we thus argue that these methods may overestimate species in cases in which genetic divergence is unusually large and discuss the systematic implications of our findings.
River regulation alters drivers of primary productivity along a tropical river-estuary system
Authors: Burford M. A. , Revill A. T. , Palmer D. W. , Clementson L. , Robson B. J. , Webster I. T.
Published: November 2018

Worldwide, rivers continue to be dammed to supply water for humans. The resulting regulation of downstream flow impacts on biogeochemical and physical processes, potentially affecting river and estuarine productivity. Our study tested the hypothesis that primary production in the downstream freshwater reaches of a dammed river was less limited by light and nutrients relative to downstream estuarine primary production. In a tropical dryland Australian river estuary, we found that water-column primary productivity was highest at freshwater sites that had lowest light attenuation. Nitrogen may also have limited primary productivity. Below the freshwater zone was a region of macrotidal mixing with high concentrations of suspended soil particles, nutrients and chlorophyll a, and lower but variable primary productivity rates. Light controlled productivity, but the algal cells may also have been osmotically stressed due to increasing salinity. Further downstream in the estuary, primary productivity was lower than the freshwater reaches and light and nutrient availability appear to be a factor. Therefore the reduced magnitude of peak-flow events due to flow regulation, and the resulting decrease in nutrient export, is likely to be negatively impacting estuarine primary production. This has implications for future development of dams where rivers have highly seasonal flow.
Reproductive demography of a temperate protogynous and herbivorous fish, Odax pullus (Labridae, Odacini)
Authors: Trip E. D. L. , Raubenheimer D. , Clements K. D. , Choat J. H.
Published: November 2018

A common view is that, in marine fishes, herbivory and sex change are subject to physiological constraints at high latitudes, which are likely to affect growth rates and reproductive outputs. The present study examines the reproductive demography of Odax pullus, an herbivorous and protogynous species of temperate New Zealand. We establish an otolith-based methodology for age estimation and investigate sex-specific growth, longevity and age-based reproductive events. Individuals achieved a maximum age of 11 years, reached 85% of adult body size (455 mm FL) within the first 3.5 years of life, were sexually mature by the age of 1.1–1.5 years and changed sex at 2.8–3.5 years, indicating fast simultaneous somatic and reproductive growth. There was no significant difference in growth or body size between the sexes. Ovary weight of spawning females increased significantly with size and age, suggesting the presence of size- and age-fecundity skews underlying the absence of sex change in larger and older females. Testes of reproductively active males comprised less than 1% of bodyweight, suggesting pair-spawning and little sperm competition. The present study provides metrics to support comparisons of the demography of this temperate protogynous and herbivorous labrid across spatial or temporal strata.
The Biology, Migration, and Growth Rate of the School Shark, Galeorhinus australis (Macleay) (Carcharhanidae) in the South-eastern Australian Waters.
Authors: Olsen AM
Published: November 2018

The school shark fishery in south-eastern Australian waters has operated
on a homogeneous stock which has a low reproductive potential. The species
is slow-growing; the smallest mature males (120 cm) are over 8 yr of age
and the smallest mature females (135 cm) are at least 2 yr older. The gestation
period is approximately 6 months and it is estimated that only about
half the female population bear young each year.
Each gravid female carries 17-41 young with a mean number of 28.
The lengths of the normal full-term embryos range from 280 to 350 mm with
a mean for both sexes of 300 mm. The larger females tend to have the longest
embryos. Slightly more male than female young (54 : 46) are born.
Because the inshore populations of juveniles have been dwindling and
the size of the older stock is decreasing, it is believed that this slow-growing
species is being overfished. Measures aimed at protecting school sharks in
their vulnerable stages have been proposed. Any conservation programme will
be long-term as this shark has such a low reproductive capacity.
Some Uses of Probability Paper in the Analysis of Size Frequency Distributions
Authors: Cassie RM
Published: November 2018

Methods are described by which the component groups may be extracted from polymodal size frequency samples by the use of probability graph paper. Four examples are given illustrating: the solution of a distribution with more than two modes and with only one exposed flank; the coordination of fish age determinations by the two methods, length frequency analysis and scale reading; a bivariate sample where the two means coincide though the standard deviations are different; a method of correcting for truncation.
Functional leaf anatomy and ultrastructure in a marine angiosperm, Syringodium isoetifolium (Aschers.) Dandy (Cymodoceaceae)
Authors: Kuo J
Published: November 2018

The terete leaf blade of Syringodium isoetifolium (Aschers.) Dandy from south-western
Australia has uniformly small epidermal cells and a few large secretory cells. Mesophyll
tissues contain several air lacunae, a central longitudinal vascular bundle, and eight to
twelve peripheral longitudinal vascular bundles, but no fibre bundles. The total volume
of air lacunae is about 10% that of the leaf blades, but the total surface area of air
lacunae is similar to that of leaf blades. The leaf cuticle appears as a thin, electron-transparent
layer. Leaf-blade epidermal cells have a large central vacuole and peripheral cytoplasm
containing many chloroplasts that lack starch grains. Wall ingrowths are absent.
However, the small region between the walls and the plasmalemma could play an important
role in nutrient absorption. Plasmodesmata appear to be absent between adjacent epidermal
cells, and also between epidermal and mesophyll cells, suggesting that there is only an apoplastic
pathway for the transport of photosynthate to the vascular tissues. Each vascular bundle is
surrounded by a layer of sheath cells, which are characterized by the presence of suberized lamellae
in their walls. These may act to reduce the apoplastic exchange of solutes and water between
the mesophyll and vascular tissues. Xylem elements, represented by large lumens and intensely
hydrolysed walls, may not be present in all peripheral vascular bundles.
Two types of sieve elements occur in S. isoetifolium leaf blades: normal thin-walled ones with large
lumens, and thick-walled ones with reduced lumens, representing the photophloem and the
metaphloem, respectively.
Photosynthetic characteristics of seagrasses (Cymodocea serrulata, Thalassia hemprichii and Zostera capricornia) in a low-light environment, with a comparison of leaf-marking and lacunal-gas measurements of productivity
Authors: Pollard PC , Greenway M
Published: November 2018

We describe the photosynthetic characteristics of three seagrasses and the relationship between their
production and natural light intensities (photosynthesis-irradiance response, i.e. PI curves). Seagrass
production (gross production minus shoot respiration) was measured in the field by the rate of gas
release from the lacuna1 space of whole seagrass shoots and compared with net leaf production.
Field work was carried out on the seagrasses Cymodocea serrulata (R. Br.) Aschers, and Magnus,
Thalassia hemprichii (Ehrenb.) Aschers., and Zostera capricornia Aschers. in the turbid, warm waters
of Cairns Harbour, Queensland, Australia.
The photosynthetic efficiencies (the initial slope of the PI curves) of all of the seagrass species were
10 times greater than any previously measured for the same species in higher-light environments.
The high compensating light intensities (80-92 �E m-2 s-1) showed that the plants have high respiration
rates that were probably due to the high water temperatures (29-33�C) of the harbour. The seagrasses
responded to small increases of light at low light intensities by rapidly reaching saturating light
intensities, and the maximum rates of production were between 0.4 and 0.6 mg C h-1 shoot-1.
The average period of exposure to saturating light intensity was 2 h day-1. One-quarter of the gross
production was lost to plant respiration. The net productivity and respiration of all three seagrasses
was calculated from this photoperiod.
Net leaf production in situ compared well with the seagrass production estimates that were measured
with the lacunal-gas technique. Most of the production appeared to be allocated to the above-ground
tissue, a feature consistent with seagrasses growing in low-light and terrigenous sediments.
The S. Domingos Mine: A study of heavy metal contamination in the water column and sediments of the Chanca River Basin by discharge from an ancient cupriferous pyrite mine (Portugal)
Authors: Pereira EG , Moura I , Costa JR , Mahony JD , Thomann RV
Published: November 2018

The water column and the sediment in the S. Domingos Mine area and the associated drainage stream are heavily contaminated by heavy metals. The Chanca Reservoir, into which this stream flows, shows a localized area where the sediment is contaminated by heavy metals, but in general the water column does not show any contamination. Both water column and sediment quality were analysed, including determination of total heavy metal concentration as well as acid volatile sulfide (AVS) and simultaneously extracted metal (SEM). The ratio between SEM and AVS is less then 1 for almost all sampling sites, showing that the Chanca Reservoir appears to be protected in most areas with respect to both sediment and water column toxity.
Consolidation of dredged sludge, measured by an acoustic densitometer
Authors: Verbeek H , Cornelisse JM
Published: November 2018

A field study was conducted on the Cromstrijen dump site in the Rhine-Meuse estuary to find the risks of open-water dumping by estimating the impact effects and spreading of freshly deposited sludge and the consolidation of dumped material. The site is used to dump sludge of acceptable quality from maintenance dredging of waterways and local harbours. The investigated sludge came from a navigation channel and was dredged and transported by a hopper dredge. On the dump site, a small section was marked in which the dump took place.
A field version of an existing laboratory acoustic densitometer was used to take a profile of the dry-weight concentration of the sediment bed as measured by the attenuation of high-frequency sound waves. The instrument was calibrated with the aid of homogenized field samples. The acoustic densitometer was useful for obtaining a profile of the bed density.
With an echo-sounder, an attempt was made to evaluate the consolidation of the dumped sludge. The use of side-scan sonar at the dump site showed a crater with steep banks, surrounded by a thin layer of excess sediment extending over 8400 m². This was only 20% of the dumped sludge; the remaining material was transported outside the measurement section as a density current owing to near-bed surge and local bed slope. The results of the field study are compared with those of previous work and with estimates of the rate and area of distortion derived from theoretical models for the movement of a flow with negative buoyancy.
Effect of major flow diversion on sediment nutrient release in a stratified reservoir
Authors: Schadlow SG , Hamilton DP
Published: November 2018

A process-based, hydrodynamic model that describes the mixing and transport processes in a stratified lake has been coupled to an ecological model to examine the relationship between the stratification and internal nutrient loading. The ecological model includes descriptions of algal production, nutrient cycling (including sediment release) and oxygen dynamics. An example is presented of the use of the model to examine interactions between stratification, sediment nutrient release and phytoplankton production when there is a major diversion of the inflow to a drinking water reservoir.
Transport of adsorbing metals from stream water to a stationary sand-bed in a laboratory flume
Authors: Eylers H , Brooks NH , Morgan JJ
Published: November 2018

The transport of zinc and lithium ions between the overlying water column and the stationary sand-bed in a laboratory flume with bottom bedforms is investigated. Experiments have been performed under simplified conditions in a recirculating laboratory flume with straight impermeable walls and a sand-bed. The sand is well sorted and acid-washed to provide reproducible experimental conditions. The chemical composition of the recirculating water is controlled and steady flow conditions are maintained in the experiments. The concentrations of initially added metal ions are monitored both in the circulating overlying water and in the pore water of the sediment bed.
Batch experiments were performed to investigate the chemical partitioning of the metal ions to the sand grain surfaces, and the data were compared with adsorption values obtained from the flume experiments.
A model based on pressure-driven advective flow and linear partitioning of the pollutant to the sediment has been developed and accurately predicts the rate of transfer of the metal ions (zinc and lithium) into the bed in the case of stationary bedforms.
Colloidal particle exchange between stream and stream bed in a laboratory flume
Authors: Packman AI , Brooks NH
Published: November 2018

The exchange of fine natural particles between the surface and pore waters of a sand-bed stream has been investigated in a laboratory flume. At the beginning of each experiment, kaolinite clay is added to the recirculating surface water flowing over a sand bed with dunes. Transport of clay into the bed is then determined by measuring the decrease of clay concentration in the surface water with time. Two conclusions can be drawn from the experiments done to date. First, although the kaolinite particles are too small to settle appreciably in the surface flow, they can be trapped to a great extent in the bed. Second, the trapped clay can be released when the surface water no longer has a high clay concentration.
Bioconcentration of polychlorinated biphenyls (PCBs) in chironomid larvae, oligochaete worms and fish from contaminated lake sediment
Authors: Bremle G , Ewald G
Published: November 2018

Values were determined for PCB bioconcentration factors (BCFs) for fish and BSF (ratio of organism-to-sediment PCB concentration) for fish, oligochaete worms and chironomid larvae, collected in a PCB-contaminated lake in the south of Sweden. Generally, the BCF and BSF increased slightly with increasing PCB lipophilicity. This was not the case for PCBs with a log octanol/water partitioning coefficient of >7, for which the BCF and BSF values levelled off or decreased. The BSF curves for PCBs were similar for the two benthic organisms but different for fish. There was a variation in PCB domain patterns for the benthic organisms between sampling points. This could be an effect of varying bioavailability of the PCBs in the different sediment types.
Despite the similarity in BSF patterns for the benthic organisms, the PCB concentration in chironomids was about twice that in oligochaete worms. The chironomid lipids contained more than twice the amount of non-polar lipid components than did the lipids in oligochaete worms, which probably influenced the lipid/sediment equilibrium of PCB.
On the seasonal migration of the cyanobacterium Gloeotrichia echinulata in Lake Erken, Sweden, and its influence on the pelagic population
Authors: Forsell L , Pettersson K
Published: November 2018

The quantity and distribution of colonies of Gloeotrichia echinulata migrating from the sediments into the water column were studied in Lake Erken by the use of inverted traps. The epilimnetic population and the phosphorus status of the epilimnetic colonies were quantified.
The numbers of colonies in the traps were greatest in the shallower areas. As the stratification became weaker and the epilimnetic population declined, the amount of colonies in all the traps increased markedly. Most of the colonies in the traps were due to redistribution within the water column.
On the assumption that no epilimnetic uptake of phosphorus occurred in G. echinulata, the internal loading of phosphorus due to migrating colonies was calculated to be between 0.4 and 0.6 mg P m-2 day-1 during July and August. The proportion of newly migrated colonies in the epilimnetic G. echinulata population was calculated to be around 50% for the period before the epilimnetic population maximum. The increasing phosphorus content of the epilimnetic colonies after the population maximum indicates that the migration continued even after this.
Spatial variability in sediment composition and evidence for resuspension in a large, deep lake
Authors: Lebo ME , Reuter JE
Published: November 2018

Spatial variability in the composition of sediments in Pyramid Lake, Nevada, was assessed in June 1992 by collecting surficial samples at 32 sites. For those sites, organic fractions were highest in the centre of the lake and low near the single inflow to the system. The spatial patterns for organic C, N, and P in lake sediments indicated that small organic-rich particles are preferentially deposited in the centre of the lake. This sorting of particles by water depth was supported by a corresponding decrease in the particle size distribution of sediments with station depth and by limited sediment-trap data. Further, a comparison of sediment-trap particle flux rates with the net sediment accumulation rate for the centre of the lake based on 210Pb decay indicated that the resuspension of bottom sediments in Pyramid Lake (zmax = 102 m) must occur throughout the lake.
Empirical orthogonal functional analysis of sediment concentration profiles subjected to waves and currents
Authors: Wai OWH , Bedford KW
Published: November 2018

Spatial and temporal eigenfunctions for profiles of suspended-sediment concentrations collected during three distinct flow conditions (current-dominated, wave-dominated, and wave- current-dominated) were used to study the non-linear sediment dynamics in the water column. The eigenfunctions were obtained by the method of Empirical Orthogonal Function (EOF) analysis. The variance distribution of the first spatial eigenfunction associated with the largest eigenvalue reflects the characteristic structure of the original profiles, and the second largest spatial eigenfunction indicates the location of possible structural or boundary layer changes in the profiles. The first temporal eigenfunctions for the current- and wave-driven profiles correlate with the turbulence-wave kinetic energy. Because of the complexity of the wave-current flow field, the first two temporal eigenfunctions for the wave-current-driven profiles have a weak relation with the major driving forces. Orthogonal functions can be used to reconstruct sediment concentration profiles efficiently and accurately. To reconstruct 97% of the variation of 10-min averaged profiles in a 2-h data record, only two eigenvalues, and their corresponding orthogonal functions are required, even in the complex wave-current flow field.
110 Temporal Changes in Endometrial Gene Expression Between Ipsi- and Contralateral Uterine Horns in Cattle
Authors: Sánchez J. M. , Passaro C. , Forde N. , Behura S. , Browne J. A. , Mathew D. J. , Butler S. T. , Spencer T. E. , Lonergan P.
Published: November 2018

The transfer of an embryo into the uterine horn contralateral to the ovary bearing the corpus luteum has been associated with a decreased pregnancy rate in cattle compared with transfer into the ipsilateral horn. These findings suggest that the environment in the contralateral horn is less conducive to supporting conceptus development than that of the ipsilateral horn. Therefore, this study compared the endometrial transcriptome of the ipsi- and contralateral uterine horns during the luteal phase. Endometrial samples from the ipsi- (IPSI) and contralateral (CONTRA) horns were collected from synchronized nonpregnant beef heifers on Days 5, 7, 13 or 16 post-oestrus (n = 5 heifers per time point). Total RNA was isolated and sequenced. Differences in the transcriptome were determined by edgeR-robust analysis. Principal component analysis found that IPSI and CONTRA have distinct patterns of gene expression on each day, with Day 5 exhibiting the most variation and Day 16 being least variable. Further, the 2 uterine horns had distinct expression patterns on Day 5, with IPSI exhibiting significantly higher variation in gene expression compared twitho CONTRA. EdgeR-robust analysis found 217 (201 up- and 16 down-regulated), 54 (44 up- and 10 down-regulated), 14 (13 up- and 1 down-regulated), and 18 (14 up- and 4 down-regulated) differentially expressed genes (DEG; >2-fold change, false discovery rate P < 0.05) between IPSI and CONTRA endometria on Days 5, 7, 13, and 16 of the oestrous cycle, respectively. The top 5 canonical pathways associated with DEG between IPSI and CONTRA during the luteal phase of the oestrous cycle were involved in signalling pathways regulating pluripotency of stem cells (73/138), progesterone-mediated oocyte maturation (55/89), endometrial cancer (31/51), ErbB signalling pathway (50/87), and mTOR signalling pathway (36/61). The impact of DEG on signalling pathways was assessed using a pathway perturbation algorithm called Signalling Pathway Impact Analysis (SPIA). This topology-based pathway analysis was conducted using the Bioconductor ToPAseq package (https://bioconductor.org/packages/release/bioc/html/ToPASeq.html) and revealed that signalling pathways regulating pluripotency of stem cells showed the highest perturbation score when IPSI was compared with CONTRA irrespective of day. Discovering and cataloguing which pathways are perturbed in each uterine horn throughout the oestrous cycle may contribute to our understanding of the mechanisms underlying early embryonic loss.
Ths study was supported by Science Foundation Ireland (13/IA/1983) and the Irish Department of Agriculture, Food and The Marine (13S528).
113 Specific Impacts of Mild Feed Restriction on Gene Expression of Endometrial Luminal, Glandular and Stromal Cells in Postpartum Dairy Cows
Authors: Chankeaw W. , Lignier S. , Raliou M. , Ntallaris T. , Richard C. , Guo Y. , Sandra O. , Andersson G. , Humblot P. , Charpigny G.
Published: November 2018

Although numerous studies have examined global mRNA expression in the whole endometrium, very few studies aimed at characterising the global mRNA profile at specific cellular types within this tissue. In this study, we hypothesised that metabolic status during the postpartum period can affect specifically gene expression of endometrial luminal, glandular epithelial and stromal cells. To achieve this, endometrial biopsies were performed in 22 postpartum cows receiving either a control diet (n = 12, aiming for 35 kg/d of energy-corrected milk, ECM) or a mild restricted diet (n = 10, aiming for 25 kg/d of ECM). The diet affected the metabolic status of the cows as documented in Ntallaris et al. (2017 Theriogenology 90, 276-283). Three endometrial biopsies were collected for each cow between 12 and 15 days post-oestrus (oestrus was synchronized with CIDR and all cows had progesterone concentrations >5 ng mL−1 at time of biopsy). Biopsies were frozen in Optimal Cutting Temperature compound and then 10-µm sections were obtained by using cryostat. Slides were fixed in ethanol and stained using cresol violet. Luminal and glandular epithelial cells as well as stromal cells were harvested by laser capture microdissection using the PixCell II LCM System. Following capture, mRNA was extracted from each cellular types using the Arcturus PicoPure RNA Isolation (Thermo Fisher Scientific, Waltham, MA, USA). A genome-wide transcriptomic profile of endometrial cells from biopsies was generated with RNAseq. Samples were sequenced in 50-length paired. The average number of reads across all samples was near 100 million. Reads were mapped on the UMD3.1 assembly of the Bos taurus genome using Tophat. Quantification of gene expression has been performed using HTSeq with annotations from Ensembl. The comparisons of interest have been performed using DESEqn 2 (R package) with the statistical method proposed by Love et al. (2014 Genome Biol. 15, 550). With an adjusted P-value of 0.05, 8, 571, and 2658 genes were found significantly differentially expressed between animals fed with low or control diets for glandular, stromal, and luminal cells respectively. These results provide novel insights into mechanisms regulating endometrium physiology in postpartum dairy cows. The number of differentially expressed genes according to diet was much higher in luminal epithelial and stromal cells than in glandular cells providing evidence that these cells express differential responses to the metabolic environment to which they are exposed. Therefore, transcriptomic analyses based only on full tissue, as possibly biased by differences in cell numbers of different types could be not fully relevant.
We acknowledge the financial support of ‘Prolific’ (EU grant KBBE; 31176) and RMUTSV (Thailand)
129 Embryo Production from Fully Grown and Growing Stage Oocytes in Japanese Black Calves
Authors: Matoba S. , Takeda K. , Ohkubo Y. , Hirako M. , Hirao Y.
Published: November 2018

Before fattening of Japanese Black female calves, the ovaries are sometimes removed and discarded. Production of embryos from the oocytes residing in such ovaries is beneficial for the rescue of genetic resources. The aim of this study was to establish an embryo production system using oocytes collected from the ovaries of calves just before fattening and to investigate the correlation between the developmental competence of oocytes and the onset of puberty. Ovaries were collected from Japanese Black calves (9.5 ± 0.1 months old, n = 30, 3 replicates) in a fattening farm and separated according to the presence or absence of corpus luteum as the indicator of puberty (CL+ and CL– groups, respectively). Immature fully grown oocytes (IM oocytes), ~120 μm in diameter, were aspirated from follicles of 2 to 6 mm in diameter (CL+; n = 132, CL–; n = 41) and cultured for 22 to 23 h for maturation (IVM). After in vitro fertilization (IVF) for 6 h (designated Day 0), the oocytes were cultured for 9 days (in vitro culture, IVC) (Matoba et al. 2014 J. Dairy Sci. 97, 743-753). Growing oocytes, ~100 μm in diameter, were also collected by dissecting the follicles smaller than 1 mm in diameter. The growing oocytes were cultured for 14 days on membrane inserts for in vitro growth (IVG) (Hirao et al. 2013 Biol. Reprod. 89, 1-11). Then, IVG oocytes (CL+; n = 29, CL–; n = 32) were subjected to IVM, IVF, and IVC. Presumptive zygotes were cultured individually in microwells in culture dishes. Mitochondrial DNA (mtDNA) copy numbers (COX1 gene) of oocytes were examined (Takeda et al. 2010 Mitochondrion 10, 137-142). A comparison was made between the oocytes derived from calf ovaries and those of oocytes collected from cow ovaries by transvaginal ovum pick-up or by aspiration of the ovaries obtained at a local slaughterhouse. In IM oocytes, the rate of embryos developed to the blastocyst stage on Day 7 to 9 was higher in the CL+ group than in the CL– group (38.9 ± 2.6 v. 10.0 ± 7.1%, respectively; P < 0.05, t-test). However, IVG oocytes were compared, there was no significant difference in the blastocyst formation rate between the CL+ or CL– groups (34.7 ± 5.2 v. 19.8 ± 10.1%, respectively). The mtDNA copy numbers of matured oocytes were similar between IM and IVG oocytes irrespective of the maturity of the donor animals. In conclusion, we demonstrated the possibility of embryo production by IVM/IVF/IVC using fully grown and growing oocytes that are present in the ovaries of calves before fattening. Puberty positively affected the developmental competence of IM oocytes but the effect was not significant in IVG oocytes. Utilisation of both fully grown oocytes and growing oocytes may double the chance of rescuing genetic resources of high-breeding-value calves.
This study was partly supported by grants from the Ito Foundation. We thank staff at Mie-Katoubokujou for allowing access to calves’ ovaries.
135 Effect of Different Bovine Breeds on Efficiency of Embryo Production by Ovum Pick-Up-IVF
Authors: Sato S. , Moriyoshi M. , Dochi O. , Imai K.
Published: November 2018

Production of bovine embryos by ovum pick-up (OPU)-IVF has increased in recent years. However, numerous factors affect efficiencies of embryo production using this technology. This study was investigated the effects of different breeds on embryo production by OPU-IVF. In total, 98 OPU-IVF sessions were conducted on 41 Holstein and 27 Japanese Black cows from February 2015 to May 2017. The collected cumulus–oocyte complexes (COC) were matured for 22 h. After co-culture of COC with sperm for 6 h, the presumptive zygotes were washed and denuded by pipetting. Those zygotes were then cultured in CR1aa medium supplemented with 5% calf serum for 9 days in a micro-well culture dish. Blastocyst formation rates were analysed at 9 days post-insemination (hpi). The kinetics of embryo development was observed at 27, 31, and 55 hpi. Four factors were considered for selecting embryos to predict pregnancy competence: (1) timing of first cleavage; (2) formation of 2 blastomeres after first cleavage at 31 hpi; (3) absence of fragments after first cleavage at 31 hpi; (4) formation of 8 or more blastomeres at 55 hpi. The quality of blastocysts was compared with the proportions of embryos that were selected based on these 4 factors. Data were analysed by the Chi-squared test with Yates’ correction and Student’s t-test. Total numbers of COC from Holstein or Japanese Black cows were 1330 (n = 51) and 1543 (n = 47), respectively. However, no differences were observed in the numbers of collected and cultured COC per OPU session between Holstein (26.1 ± 20.1 and 21.7 ± 20.1) and Japanese Black (32.8 ± 24.7 and 28.7 ± 22.7) cows. The percentage of COC linked into Grade 1, 2, or 3 was 47.6, 32.1, and 10.7% for Japanese Black and 45.8, 25.6, and 12.2% for Holstein cows, respectively. The proportion of COC with expanded cumulus cells was significantly higher (P < 0.01) in Holstein (12.7%) than in Japanese Black (7.7%) cows. The number of blastocyst and transferable embryo production per OPU session in Holstein (7.5 ± 8.3 and 7.3 ± 7.7) cows was not different from that in Japanese Black (10.6 ± 9.3 and 9.8 ± 9.0) cows. Moreover, there was no difference in blastocyst formation rates between Japanese Black (36.8%) and Holstein (34.8%) cows. Percentages of embryos selected by factors 1 to 4 were 42.6, 66.8, 59.1, and 54.4% in Holstein, and 54.6, 83.2, 72.2, and 75.2% in Japanese Black cows, respectively. Proportions of blastocysts in Holstein and Japanese Black cows selected by a combination of all 4 factors were 21.6 and 36.1%, respectively. There were significant differences (P < 0.01) between the 2 breeds in terms of proportion of blastocysts selected based on individual factors as well as a combination of all 4 factors. These results suggested that the efficiency of embryo production did not differ between Japanese Black and Holstein cows. However, the quality of embryos selected by a combination of 4 factors was significantly higher in Japanese Black than in Holstein cows.
140 Endocrine Profiling in Prepubertal Stallions with Abnormal Testicular Development
Authors: Scarlet D. , Kuhl J. , Wulf M. , Ille N. , Köhne M. , Conley A. , Aurich C.
Published: November 2018

The use of anti-Müllerian hormone (AMH) as a biomarker for assessment of male gonadal activity has become increasingly widespread. Aberrant AMH concentration successfully detects cryptorchids or pathologic testes in postpubertal stallions, but the ability to use AMH to identify stallions with testicular pathologies during their prepubertal life has not been analysed so far. The objectives of this work were to (1) assess AMH, testosterone, LH, and FSH dynamics in male horses with or without testicular pathologies during the first year of life; and (2) find a reliable diagnostic approach that would enable the identification of animals that will develop abnormal testes at an early stage. Warmblood colts (n = 16) born from February to May on the same stud farm were used. Blood samples for hormone determinations were collected from birth onwards every 4 weeks until the age of 1 year. At 2 years, testicular development was assessed, total testicular volume calculated. and a blood sample collected. Concentrations of AMH, testosterone, LH, and FSH were determined in all samples; AMH (AL-115, Ansh Laboratories, Webster, TX, USA) and testosterone (DE1559, Demeditec, Kiel-Wellsee, Germany) concentrations were determined by ELISA, whereas LH and FSH concentrations were determined by radioimmunoassay. Statistical analysis (SPSS Statistics 24; IBM/SPSS, Armonk, NY, USA) was performed by ANOVA using a general linear model for repeated measures. In 2 stallions, unilateral cryptorchism, and in other 4 stallions, subnormal total testicular volume (<mean minus SD) were diagnosed at 2 years. Concentrations of AMH, testosterone, and FSH changed over time (P < 0.001) but were similar (P > 0.05) within the first year of life irrespective of testicular morphology and location. Concentration of LH at birth was lower (P = 0.05) in stallions with abnormal testes (0.3 ± 0.2 ng mL−1) than in controls (0.6 ± 0.2 ng mL−1), but did not differ thereafter. At 2 years of age, AMH concentration was higher (P < 0.01) in stallions with abnormal testes (39.7 ± 12.7 ng mL−1) than in controls (8.0 ± 0.2 ng mL−1), but no group differences with regard to LH, FSH, and testosterone existed. There was a low but significant negative correlation between AMH and FSH (P < 0.001, r = –0.24), as well as between AMH and LH (P < 0.05, r = –0.15). Also, testosterone concentration was positively correlated with FSH (P < 0.05, r = 0.18) and LH (P < 0.05, r = 0.16) concentrations. In conclusion, AMH determination can be reliably used from 2 years onwards to identify stallions with abnormal testicular development, but it is inconclusive before puberty. We concluded that LH secretion in the perinatal period is involved in testicular development and descent in the horse.
15 Effects of Timed Artificial Insemination Protocol Using Prostglandin F2α and Estradiol Benzoate on Conception Rate in High-Producing Dairy Cows
Authors: Yamaguchi M. , Takayama M. , López H.
Published: November 2018

For several years, milk production per Holstein cow has been increasing while reproductive performance has declined worldwide. Timed AI (TAI) protocols with synchronization of oestrus and ovulation are tools for the improvement of reproductive performance in high producing dairy herds. In protocols for synchronization of oestrus and ovulation, oestradiol benzoate (EB) has been used to increase the number of animals that show oestrous behaviour, synchronize ovulation, and improve conception rate (CR). The objective of this study was to compare a simple oestrus synchronization and TAI protocol using prostaglandin F2α (PG) and EB with a more complicated TAI protocol or oestrus detection and AI on CR in high-producing Holstein cows. The study was conducted from 2014 to 2016, using 1,036 Holstein cows from 3 commercial dairy herds in central Hokkaido, Japan. The average parity number was 2.6 ± 1.5, and days open averaged 152.2 ± 82.0 days. The average milk yield (305 days) was 11,348 ± 1,619 kg. Oestrus synchronization of cows was achieved using PG followed by EB and TAI (PG was given to cows with a cutoff for CL diameter of >20 mm by ultrasonography; EB (1 mg) was administered 24 h later and AI was carried out 24 to 48 h after EB injection), or by Heatsynch + CIDR [gonadotropin-releasing hormone (GnRH) injection and CIDR insertion at random stages of the oestrous cycle, CIDR removal, and PG injection 7 days later, EB injected 24 h after CIDR removal, and TAI 24 to 32 h after EB injection]. Cows observed in natural oestrus were used as controls. All cows were inseminated after the onset of standing heat or removal of the tail chalk (Paintstik®, LA-CO Industries, Elk Grove Village, IL, USA). Pregnancy diagnoses were performed using ultrasonography between 30 and 45 days after AI. The CR were compared using chi-square test. The CR (no. of pregnant cows/no. of total cows in the treatment group) of the natural oestrus group, PG + EB, and Heatsynch + CIDR cows were 39.2% (302/771), 38.7% (48/124), and 31.2% (44/141), respectively. Overall CR for the 3 groups was 38.0%. There were no significant differences in CR among the 2 groups (P > 0.07). These results show that a simple oestrus synchronization protocol with injection of PG followed by EB can be used effectively for high-producing dairy herds, yielding a satisfactory CR similar to that obtained with the Heatsynch + CIDR protocol or natural oestrus.