Analysis of the small-scale spatial patterns of free-living marine nematodes from tidal flats in the East Frisian Wadden Sea

1999 ◽  
Vol 133 (4) ◽  
pp. 717-726 ◽  
Author(s):  
D. Blome ◽  
U. Schleier ◽  
K.-H. van Bernem
Keyword(s):  
Spatial Patterns ◽  
Wadden Sea ◽  
Tidal Flats ◽  
Small Scale ◽  
Marine Nematodes ◽  
Free Living

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.

scholarly journals A new look into the small-scale dispersal of free-living marine nematodes

2011 ◽  
Vol 28 (4) ◽  
pp. 449-456 ◽  
Author(s):  
Micheli C Thomas ◽  
Paulo C Lana
Keyword(s):  
Small Scale ◽  
Marine Nematodes ◽  
Free Living ◽  
New Look

New Records of Free-Living Marine Nematodes (Nematoda: Enoplida) from East Coast of India

2012 ◽  
Vol 2 (11) ◽  
pp. 517-520
Author(s):  
VIJAYA BHANU, CH VIJAYA BHANU, CH ◽  
◽  
ANNAPURNA, C ANNAPURNA, C ◽  
SRINIVASA RAO, M SRINIVASA RAO, M ◽  
SIVA LAKSHMI, M. V SIVA LAKSHMI, M. V ◽  
...  
Keyword(s):  
East Coast ◽  
New Records ◽  
Marine Nematodes ◽  
Free Living ◽  
East Coast Of India

scholarly journals Toxicity of hydroxychloroquine, a potential treatment for COVID-19, on free-living marine nematodes

2021 ◽  
pp. 112361
Author(s):  
Manel Ben Ali ◽  
Amor Hedfi ◽  
Mohammed Almalki ◽  
Paraskevi K. Karachle ◽  
Fehmi Boufahja
Keyword(s):  
Potential Treatment ◽  
Marine Nematodes ◽  
Free Living

scholarly journals Using a Groundwater Adjusted Water Balance Approach and Copulas to Evaluate Spatial Patterns and Dependence Structures in Remote Sensing Derived Evapotranspiration Products

2021 ◽  
Vol 13 (5) ◽  
pp. 853
Author(s):  
Mohsen Soltani ◽  
Julian Koch ◽  
Simon Stisen
Keyword(s):  
Remote Sensing ◽  
Water Balance ◽  
Spatial Pattern ◽  
Spatial Patterns ◽  
Principal Component ◽  
Small Scale ◽  
Dependence Structure ◽  
Test Case ◽  
Catchment Scale ◽  
Balance Approach

This study aims to improve the standard water balance evapotranspiration (WB ET) estimate, which is typically used as benchmark data for catchment-scale ET estimation, by accounting for net intercatchment groundwater flow in the ET calculation. Using the modified WB ET approach, we examine errors and shortcomings associated with the long-term annual mean (2002–2014) spatial patterns of three remote-sensing (RS) MODIS-based ET products from MODIS16, PML_V2, and TSEB algorithms at 1 km spatial resolution over Denmark, as a test case for small-scale, energy-limited regions. Our results indicate that the novel approach of adding groundwater net in water balance ET calculation results in a more trustworthy ET spatial pattern. This is especially relevant for smaller catchments where groundwater net can be a significant component of the catchment water balance. Nevertheless, large discrepancies are observed both amongst RS ET datasets and compared to modified water balance ET spatial pattern at the national scale; however, catchment-scale analysis highlights that difference in RS ET and WB ET decreases with increasing catchment size and that 90%, 87%, and 93% of all catchments have ∆ET < ±150 mm/year for MODIS16, PML_V2, and TSEB, respectively. In addition, Copula approach captures a nonlinear structure of the joint relationship with multiple densities amongst the RS/WB ET products, showing a complex dependence structure (correlation); however, among the three RS ET datasets, MODIS16 ET shows a closer spatial pattern to the modified WB ET, as identified by a principal component analysis also. This study will help improve the water balance approach by the addition of groundwater net in the ET estimation and contribute to better understand the true correlations amongst RS/WB ET products especially over energy-limited environments.

scholarly journals Is a spatial investigation possible without long-distance refit/conjoin? Application to the MIS 11 lithic assemblage of levels E and J from La Cansaladeta site (Tarragona, Spain)

2021 ◽  
Vol 13 (9) ◽  
Author(s):  
Görkem Cenk Yeşilova ◽  
Andreu Ollé ◽  
Josep Maria Vergès
Keyword(s):  
Spatial Patterns ◽  
Spatial Information ◽  
Small Dimension ◽  
Middle Pleistocene ◽  
Small Scale ◽  
Spatial Pattern Analysis ◽  
Long Distance ◽  
Great Opportunity ◽  
Density Mapping ◽  
Study Materials

AbstractIn this manuscript, we present the first systematic refitting results of the small-scale Middle Pleistocene (MIS11) rock shelter site of La Cansaladeta. The lithic materials that have been recovered from the archaeological levels E and J were the main study materials. These levels were investigated regarding spatial pattern analysis and analyzed with auxiliary methods such as quantitative density mapping demonstration and technological analysis of the lithic clusters. Thus, the spatial patterns of the two levels were compared and discussed, in terms of connections, clusters, and movement of the lithic elements. Undoubtedly, the well preservation of the archaeological levels offered a great opportunity for the interpretation of the spatial patterns in a high-resolution perspective. La Cansaladeta has not been paid attention adequately so far may be due to the small dimension of the excavation surface or to the scarcity of faunal record. Our results show that small-scale sites without long-distance refit/conjoin connections can provide significant spatial information. Indeed, if the sites have very well-preserved archaeological levels, the absence of long connections can be supported by the auxiliary methods.

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