Small-scale distribution and salinity response of Juniperus virginiana on an Atlantic Coast barrier island

1997 ◽  
Vol 75 (1) ◽  
pp. 77-85 ◽  
Author(s):  
David W. Martin ◽  
Donald R. Young
Keyword(s):  
Ground Water ◽  
Atlantic Coast ◽  
Barrier Island ◽  
Distribution Patterns ◽  
Small Scale ◽  
Juniperus Virginiana ◽  
Plant Responses ◽  
Rooting Zone ◽  
Red Cedar ◽  
Salinity Response

A field and laboratory study examined the hypothesis that the small-scale distribution pattern of Juniperus virginiana on barrier islands is related to salinity patterns and plant responses to salinity. Temporal (May – October) and spatial variability in ground water availability, ground water salinity, and total soil chlorides were quantified across a Virginia barrier island. Groundwater depth and salinity increased throughout the summer; microtopographic position and location on the island also affected soil salinities. Highest salinities occurred near the ocean side beach and bay side marsh, as well as in low lying swales that flood during extreme high tides or storms. Median rooting zone chloride level for J. virginiana was 54 μg/g. In contrast, laboratory germination and growth studies indicated that J. virginiana was significantly affected only at high salinity levels (1000 and 1400 μg/g), suggesting that salinity is not the only factor regulating small-scale distribution patterns. The broad tolerance to salinity may account for the abundance of J. virginiana in coastal environments. Key words: barrier island, eastern red cedar, Juniperus virginiana, salinity response, water relations.

A new species of Dichelyne (Nematoda, Cucullanidae) parasitizing sciaenid fishes from off the South American Atlantic coast

2009 ◽  
Vol 54 (1) ◽  
Author(s):  
Juan Timi ◽  
Ana Lanfranchi ◽  
Luiz Tavares ◽  
José Luque
Keyword(s):  
New Species ◽  
Atlantic Coast ◽  
Length Distribution ◽  
Distribution Patterns ◽  
Nematode Species ◽  
Valid Species ◽  
South American ◽  
Type Specimens ◽  
Pacific Waters ◽  
A New Species

AbstractA new nematode species Dichelyne (Cucullanellus) sciaenidicola sp. nov. is described based on specimens collected from the Whitemouth croaker Micropogonias furnieri (Desmarest) and the Argentine croaker Umbrina canosai Berg, from coastal waters of Argentina and Brazil. These nematodes were firstly identified as D. (C.) elongatus (Törnquist, 1931), a commonly reported species from M. furnieri in South American Atlantic waters. However, other species of Dichelyne have so far been reported from this host in the same area, namely D. (C.) rodriguesi (Pinto, Fábio et Noronha, 1970), D. (C.) amaruincai (Freitas, Vicente et Ibañez, 1969) and D. (Dichelyne) micropogonii Pereira et Costa, 1996. A careful re-examination of these parasites, as well as of type specimens of all species reported from M. furnieri, revealed that these nematodes represented a new species. The new species is distinguished from most of its congeners by having papillae 5–7 and 9 forming a subventral line close to cloaca, this feature is shared with other 6 species [D. (C.) dichelyneformis (Szidat, 1950), D. (C.) fraseri (Baylis, 1929), D. (C.) abbreviatus (Rudolphi, 1819), D. (C.) adriaticus (Törnquist, 1931), D. (C.) minutus (Rudolphi, 1819) and D. (C.) mariajuliae Alarcos, Timi, Etchegoin et Sardella, 2006)], which are readily distinguished by their body size, spicules length, distribution patterns of other papillae and position of the excretory pore and deirids. Also, D. (C.) elongatus from Umbrina canariensis (Valenciennes) from West Africa is established as a new species Dichelyne (Cucullanellus) yvonnecampanae sp. nov.; D. (C.) amaruincai from Pacific waters is considered as a valid species, D. (D.) micropogonii is regarded as species inquirendae and D. (C.) rodriguesi is identified as Cucullanus sp.

Global carbon and water exchange during drought reflects adaptation of rooting depth to climate and topography

2021 ◽  
Author(s):  
Benjamin Stocker ◽  
Shersingh Tumber-Davila ◽  
Alexandra Konings ◽  
Rob Jackson
Keyword(s):  
Remote Sensing ◽  
Snow Accumulation ◽  
Rooting Depth ◽  
Small Scale ◽  
Observation Data ◽  
Systematic Bias ◽  
Thermal Infrared Remote Sensing ◽  
Near Surface ◽  
Rooting Zone ◽  
Zone Water

<p>The rooting zone water storage capacity (S) defines the total amount of water available to plants for transpiration during rain-free periods. Thereby, S determines the sensitivity of carbon and water exchanges between the land surface and the atmosphere, controls the sensitivity of ecosystem functioning to progressive drought conditions, and mediates feedbacks between soil moisture and near-surface air temperatures. While being a central quantity for water-carbon-climate coupling, S is inherently difficult to observe. Notwithstanding scarcity of observations, terrestrial biosphere and Earth system models rely on the specification of S either directly or indirectly through assuming plant rooting depth.</p><p>Here, we model S based on the assumption that plants size their rooting depth to maintain function under the expected maximum cumulative water deficit (CWD), occurring with a return period of 40 years (CWD<sub>X40</sub>), following Gao et al. (2014). CWD<sub>X40</sub> is “translated” into a rooting depth by accounting for the soil texture. CWD is defined as the cumulative evapotranspiration (ET) minus precipitation, where ET is estimated based on thermal infrared remote sensing (ALEXI-ET), and precipitation is from WATCH-WFDEI, modified by accounting for snow accumulation and melt. In contrast to other satellite remote sensing-based ET products, ALEXI-ET makes no a priori assumption about S and, as our evaluation shows, exhibits no systematic bias with increasing CWD. It thus provides a robust observation of surface water loss and enables estimation of S with global coverage at 0.05° (~5 km) resolution.</p><p>Modelled S and its variations across biomes is largely consistent with observed rooting depth, provided as ecosystem-level maximum estimates by Schenk et al. (2002), and a recently compiled comprehensive plant-level dataset. In spite of the general agreement of modelled and observed rooting depth across large climatic gradients, comparisons between local observations and global model predictions are mired by a scale mismatch that is particularly relevant for plant rooting depth, for which the small-scale topographical setting and hydrological conditions, in particular the water table depth, pose strong controls.</p><p>To resolve this limitation, we investigate the sensitivity of photosynthesis (estimated by sun-induced fluorescence, SIF), and of the evaporative fraction (EF, defined as ET over net radiation) to CWD. By employing first principles for the constraint of rooting zone water availability on ET and photosynthesis, it can be derived how their sensitivity to the increasing CWD relates to S. We make use of this relationship to provide an alternative and independent estimate of S (S<sub>dSIF</sub> and S<sub>dEF</sub>), informed by Earth observation data, to which S, modelled using CWD<sub>X40</sub>, can be compared. Our comparison reveals a strong correlation (R<sup>2</sup>=0.54) and tight consistency in magnitude between the two approaches for estimating S. </p><p>Our analysis suggests adaptation of plant structure to prevailing climatic conditions and drought regimes across the globe and at catchment scale and demonstrates its implications for land-atmosphere exchange. Our global high-resolution mapping of S reveals contrasts between plant growth forms (grasslands vs. forests) and a discrepant importance across the landscape of plants’ access to water stored at depth, and enables an observation-informed specification of S in global models.</p>

Distribution Patterns of Escherichia coli O157:H7 in Ground Beef Produced by a Laboratory-Scale Grinder†

2002 ◽  
Vol 65 (12) ◽  
pp. 1894-1902 ◽  
Author(s):  
ROLANDO A. FLORES ◽  
MARK L. TAMPLIN
Keyword(s):  
Escherichia Coli ◽  
Ground Beef ◽  
Distribution Patterns ◽  
Small Scale ◽  
Escherichia Coli O157 ◽  
Inoculum Level ◽  
E Coli ◽  
Specific Distribution ◽  
Low Levels ◽  
G Prior

This study determined the distribution patterns of Escherichia coli O157:H7 in ground beef when a contaminated beef trim was introduced into a batch of uncontaminated beef trims prior to grinding in a small-scale laboratory grinder. A beef trim (15.3 ± 2 g) was inoculated with a rifampicin-resistant strain of E. coli O157:H7 (E. coli O157:H7rif) and introduced into a stream of noncontaminated beef (322 ± 33 g) prior to grinding. Seven inoculum levels (6, 5, and 4 total log CFU [high]; and 3, 2, 1, and 0 total log CFU [low]) were studied in triplicate. E. coli O157:H7rif was not detected in 3.1 to 43% of the ground beef inoculated with the high levels or in 3.4 to 96.9% of the ground beef inoculated with the low levels. For all inoculum levels studied, the five ground beef fractions (each 7.8 ± 0.6 g) with the highest pathogen levels accounted for 59 to 100% of the total pathogens detected. For all inoculum levels, there was a linear relationship between the quantity of ground beef containing E. coli O157:H7rif and the inoculum level. The quantity of E. coli O157:H7rif in the beef remaining in the grinder was proportional to the inoculum level and was related to the location in the grinder. Different components of the grinder accumulated E. coli O157:H7rif in different quantities, with the most significant accumulation being in the nut (collar) that attaches the die to the blade. This study determined specific distribution patterns of E. coli O157:H7rif after the grinding of a contaminated beef trim along with uncontaminated trims, and the results indicate that the grinding operation should be regarded as a means of distribution of microbial contamination in risk analyses of ground beef operations.

scholarly journals ADAPTATION PATHWAY FOR A BARRIER ISLAND TO FUTURE HURRICANES

2018 ◽  
pp. 52
Author(s):  
Stephanie Smallegan ◽  
Evan Mazur
Keyword(s):  
Storm Surge ◽  
Atlantic Coast ◽  
Barrier Island ◽  
Hurricane Sandy ◽  
Water Levels ◽  
Storm Damage ◽  
Sea Levels ◽  
The North ◽  
Adaptation Pathway ◽  
Comprehensive Study

The numerical model XBeach is used to simulate hydrodynamics and morphological change of Bay Head, NJ, which is located on a developed barrier island. Bay Head is fronted with a seawall buried beneath its dunes, and the seawall has been shown to mitigate damage due to storm surge and waves during Hurricane Sandy (2012). The objective of this study is to re-evaluate the effectiveness of the seawall in mitigating damage from a synthetic storm and sea level rise, and refine an adaptation pathway previously created for Bay Head. Utilizing the wave and surge data generated from the North Atlantic Coast Comprehensive Study, synthetic Storm 391 is simulated using XBeach. Model results show the seawall is overtopped by storm surge and waves, causing overwash and reducing dune heights. As sea levels rise, the backbarrier region of the barrier island is severely eroded and the seawall acts as a barrier preventing elevated bay water levels from freely flowing across the island and into the ocean, exacerbating sediment transport on the backbarrier. To fully evaluate the capabilities and limitations of the seawall in mitigating storm damage, additional synthetic storms need to be simulated and the results re-evaluated. This will, in turn, lead to a comprehensive, more robust adaptation pathway for Bay Head.

Spatial aggregation patterns of free-living marine nematodes in contrasting sandy beach micro-habitats

2010 ◽  
Vol 91 (3) ◽  
pp. 615-622 ◽  
Author(s):  
Ruth Gingold ◽  
Silvia E. Ibarra-Obando ◽  
Axayácatl Rocha-Olivares
Keyword(s):  
Negative Correlation ◽  
Sandy Beach ◽  
Distribution Patterns ◽  
Significant Negative Correlation ◽  
Small Scale ◽  
Spatial Distributions ◽  
Biological Processes ◽  
Marine Nematodes ◽  
Free Living ◽  
Biological Similarity

In the absence of chemical or physical gradients, random displacement of organisms can result in unpredictable distribution patterns. In spite of a limited locomotive capability, marine nematodes may choose where to settle after re-suspension and may maintain their position in the sediment under calm conditions, leading to small-scale (<1 m) spatial variability. However, in more energetic environments, nematodes become re-suspended with sediments and re-distributed at distances dependent on prevalent hydrodynamic regimes, from metre- to decametre-scale or more. In this study, we tested the hypothesis that micro-habitats (i.e. runnels and sandbars) in a macrotidal sandy beach influence the distribution patterns of free-living marine nematodes by exhibiting contrasting hydrodynamic regimes. Specifically, we predicted patchier distributions in the calmer environment (runnel). We sampled nematodes in each habitat from <1 m to decametre scales. Our results show more heterogeneous spatial distributions in the runnel, presumably owing to a predominance of active displacement under calmer conditions and sediment cohesion by algal films. Biological similarity among runnel replicates was low, whereas replicates from the sandbar exhibited higher similarity, presumably because of homogenization of the sediment and inhabiting fauna by tidal currents. A significant negative correlation between biological similarity and sampling distance was found in the runnel, but not in the sandbar. The most similar samples were the closest in the runnel and the most distant in the sandbar. More patchily distributed taxa were found in the runnel and a larger fraction of homogeneously or randomly distributed taxa in the sandbar. We conclude that different hydrodynamic regimes in contrasting intertidal micro-habitats significantly influenced the nematofaunal distribution, resulting in different spatial patterns next to one another in the same beach. This has significant implications for sampling and monitoring designs and begs the need for detailed studies about the physical and biological processes governing meiobenthic communities.

Patterns of abundance and size of Dictyoceratid sponges among neighbouring islands in central Torres Strait, Australia

2007 ◽  
Vol 58 (2) ◽  
pp. 204 ◽  
Author(s):  
Alan R. Duckworth ◽  
Carsten W. Wolff
Keyword(s):  
Spatial Scales ◽  
Distribution Patterns ◽  
Small Scale ◽  
Size Frequency Distribution ◽  
Abundance Patterns ◽  
Size Frequency ◽  
Dysidea Herbacea ◽  
Torres Strait ◽  
Study Sites ◽  
Species Specific

Distribution and size frequency patterns of sessile organisms such as sponges may vary among and within neighbouring reefs. In the present study, we examined small-scale variation of dictyoceratid sponges (class Demospongiae), commonly found on coral reefs, by surveying six neighbouring islands in central Torres Strait. Each island had four study sites, at least 1 km apart, with each site consisting of three shallow (4 to 6 m) and three deep (10 to 15 m) 20 m2 transects. For each transect, we recorded the number of each species and measured the size of the more common dictyoceratid sponges. Seven species of dictyoceratid were recorded in central Torres Strait, with only three species, Coscinoderma sp., Dysidea herbacea and Hyrtios erecta, common to all six islands. Abundance patterns generally varied greatly among islands or sites within islands, perhaps resulting from a combination of physical, biological and stochastic factors. More dictyoceratids were found in deeper water; however, abundance across depth for some species varied among islands or sites. Size-frequency distribution patterns also varied greatly among islands and dictyoceratid species, indicating that factors that may promote growth for one species may not necessarily promote growth for a related species. This study shows that patterns of abundance and size of dictyoceratids can vary greatly over small spatial scales, and that patterns are species-specific.

Cryptic species in sympatry: nonrandom small-scale distribution patterns inBostrychia intricata(Ceramiales, Rhodophyta)

Phycologia ◽  
2016 ◽  
Vol 55 (4) ◽  
pp. 424-430 ◽  
Author(s):  
Narongrit Muangmai ◽  
Ulla von Ammon ◽  
Giuseppe C. Zuccarello
Keyword(s):  
Cryptic Species ◽  
Distribution Patterns ◽  
Small Scale

Dispersal of eastern red cedar (Juniperus virginiana) into pastures: an overview

1987 ◽  
Vol 65 (6) ◽  
pp. 1092-1095 ◽  
Author(s):  
Anthonie M. A. Holthuijzen ◽  
Terry L. Sharik ◽  
James D. Fraser
Keyword(s):  
Growing Season ◽  
Seed Banks ◽  
Physiological Adaptation ◽  
Juniperus Virginiana ◽  
Similar Distribution ◽  
Eastern Red Cedar ◽  
Red Cedar ◽  
Seed Sources ◽  
Seed Shadows ◽  
Recovered Material

Seed dispersal, predispersal and postdispersal seed predation, seed dormancy, and germination were followed for four cone-bearing eastern red cedar trees (Juniperus virginiana L.), a predominantly avian-dispersed plant species, in pastures in southwest Virginia from June 1981 through May 1982. Within 12 m from the source trees, 34.7% of the total cone crop was recovered. Recovered material consisted of unripe cones, ripe cones, parasitized cones, and pulpless seeds evacuated by birds, averaging 17.9, 11.6, 1.0, and 4.2%, respectively, of the cone crop. Predispersal avian predation of seeds accounted for 3.1% of the cone crop. After 1 year 0.9% of the cones remained on the trees. The remaining 61.3% of the cone crop was dispersed at least 12 m from the source trees. Less than 3% of the cone crop is likely to germinate within 12 m of the source trees, while about 25% is likely to germinate at greater distances. Red cedar seeds passed unharmed through the digestive tract of avian dispersers and showed greater total germination than manually depulped seeds. Red cedar seed banks were not found under a chronosequence of red cedar stands; seeds generally lost their viability within one growing season. Seed shadows decreased exponentially with distance from cone-bearing trees. A similar distribution function was reflected in the spatial distribution of red cedar cohorts colonizing pastures near source trees. The large cone crop, diverse avian disperser assemblage, physiological adaptation of red cedar to open, xeric sites, and availability of seed sources in fence rows contribute to the successful invasion of pastures by this species.

The Red Cedar (Juniperus virginiana L.) Seed Shadow along a Fenceline

1985 ◽  
Vol 113 (1) ◽  
pp. 200 ◽  
Author(s):  
Anthonie M. A. Holthuijzen ◽  
Terry L. Sharik
Keyword(s):  
Juniperus Virginiana ◽  
Seed Shadow ◽  
Red Cedar
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