scholarly journals Shell morphology, growth and longevity of Unio tumidus (Bivalvia: Unionidae) from an archaeological site and contemporary population inhabiting the Oder estuary

Hydrobiologia ◽  
2021 ◽  
Author(s):  
Przemysław Czerniejewski ◽  
Jarosław Dąbrowski ◽  
Wawrzyniec Wawrzyniak ◽  
Adam Brysiewicz ◽  
Orina Surma
Keyword(s):  
Age Structure ◽  
Shell Length ◽  
Shell Growth ◽  
River Estuary ◽  
Morphological Characteristics ◽  
Archaeological Site ◽  
Shell Morphology ◽  
Baltic Basin ◽  
Length Width ◽  
Unio Tumidus

AbstractMussel shells are often found in archaeological excavations and can provide information useful for ecological reconstruction and assessment of anthropogenic impact on waters. In this study, two sample groups of swollen river mussel (Unio tumidus) which occurred during the Early Middle Ages (EMS) and currently (MS) in the Oder river estuary (Baltic basin) were compared. Allometric shell growth, morphological characteristics of the shell (length, width, height and thickness), age structure and growth of mussels were analysed using the von Bertalanffy equation. All three types of allometric growth (isometry and both positive and negative allometry) were observed in the studied mussels. In both groups, typical values of shell length, width, height and thickness were recorded. However, higher values of these morphological characteristics were recorded in the EMS group. Moreover, the EMS group, compared with the MS group of U. tumidus, was characterised by a higher longevity (12 and 10 years, respectively) and asymmetric length (L∞) (93.09 and 83.23 mm, respectively). Both groups of mussels had a similar growth rate (k). Larger shell sizes in the EMS group were probably caused by differential preservation and/or differential archaeological recovery, and resulted from differences in the age structure, especially higher mortality rate amongst individuals older than 6 years in the MS group.

Biometrics of the mussel Anodonta cygnea (L.) inhabiting in 2005 the Binowo and Bobolin Lakes near Szczecin

2007 ◽  
Vol 36 (3) ◽  
Author(s):  
Juliusz Chojnacki ◽  
Agnieszka Lewandowska ◽  
Beata Rosińska
Keyword(s):  
Age Structure ◽  
Shell Length ◽  
Mussel Population ◽  
Anodonta Cygnea ◽  
Length Width ◽  
Positive Correlations

Biometrics of the musselResearch on the swan mussel population was conducted in 2005 on a sample of 497 individuals inhabiting Binowo and Bobolin Lakes, Szczecin, Poland. Length, width, height and age of individuals was examined. Binowo Lake was inhabited by individuals aged 1+ to 7+ years, while individuals aged 1+ to 6+ inhabit Bobolin Lake. Measurable features of swan mussels inhabiting Binowo Lake were as follows: individuals were 3.80 to 10.20 cm long, 1.70 to 5.70 cm wide, 0.70 to 3.70 cm thick, and in Bobolin Lake, 4.00 to 15.20 cm long, 2.20 to 7.70 cm wide, 0.80 to 5.70 cm thick. The age structure of both populations included individuals of diverse ages, with 3 and 4-year old individuals dominating in both lakes. A modest fraction of the youngest individuals (1, 2-year old) as well as the oldest (6, 7-year old) was observed in the examined lakes. All correlations between shell length, width, height and mussel age showed large positive correlations and results obtained from both lakes were similar.

scholarly journals A Novel GIS-Based Approach for Automated Detection of Nearshore Sandbar Morphological Characteristics in Optical Satellite Imagery

2021 ◽  
Vol 13 (11) ◽  
pp. 2233
Author(s):  
Rasa Janušaitė ◽  
Laurynas Jukna ◽  
Darius Jarmalavičius ◽  
Donatas Pupienis ◽  
Gintautas Žilinskas
Keyword(s):  
Satellite Imagery ◽  
Morphological Characteristics ◽  
Unsupervised Classification ◽  
Landsat 8 ◽  
Multi Scale ◽  
Medium Resolution ◽  
Wide Range ◽  
Position Index ◽  
Local Relief ◽  
Length Width

Satellite remote sensing is a valuable tool for coastal management, enabling the possibility to repeatedly observe nearshore sandbars. However, a lack of methodological approaches for sandbar detection prevents the wider use of satellite data in sandbar studies. In this paper, a novel fully automated approach to extract nearshore sandbars in high–medium-resolution satellite imagery using a GIS-based algorithm is proposed. The method is composed of a multi-step workflow providing a wide range of data with morphological nearshore characteristics, which include nearshore local relief, extracted sandbars, their crests and shoreline. The proposed processing chain involves a combination of spectral indices, ISODATA unsupervised classification, multi-scale Relative Bathymetric Position Index (RBPI), criteria-based selection operations, spatial statistics and filtering. The algorithm has been tested with 145 dates of PlanetScope and RapidEye imagery using a case study of the complex multiple sandbar system on the Curonian Spit coast, Baltic Sea. The comparison of results against 4 years of in situ bathymetric surveys shows a strong agreement between measured and derived sandbar crest positions (R2 = 0.999 and 0.997) with an average RMSE of 5.8 and 7 m for PlanetScope and RapidEye sensors, respectively. The accuracy of the proposed approach implies its feasibility to study inter-annual and seasonal sandbar behaviour and short-term changes related to high-impact events. Algorithm-provided outputs enable the possibility to evaluate a range of sandbar characteristics such as distance from shoreline, length, width, count or shape at a relevant spatiotemporal scale. The design of the method determines its compatibility with most sandbar morphologies and suitability to other sandy nearshores. Tests of the described technique with Sentinel-2 MSI and Landsat-8 OLI data show that it can be applied to publicly available medium resolution satellite imagery of other sensors.

SOLVING THE PUZZLE OF THE BIVALVE SHELL FRAGMENT: INFERRING THE ORIGINAL ABUNDANCE AND SIZE FREQUENCY FROM THE FRAGMENTED RECORD

Palaios ◽  
2020 ◽  
Vol 35 (10) ◽  
pp. 432-445
Author(s):  
ERIC N. POWELL
Keyword(s):  
Shell Model ◽  
Shell Length ◽  
Shell Thickness ◽  
Conservative Estimate ◽  
Potential Donor ◽  
Size Frequency ◽  
Shell Fragment ◽  
Length Width ◽  
Bivalve Shell ◽  
Original Size

ABSTRACT Much of the contribution of bivalves to paleoecology is based on the fraction preserved whole. The use of fragments has been limited by the inability to reconstruct the whole shell. For this study, shells of selected species were broken, metrics obtained for shell reconstruction, and a stepwise model developed and tested to evaluate the potential of reconstructing whole shells from fragments. The model is based on the facts that shell thickness is well correlated with shell length, width, and weight, that fragments can be assigned to shell areas, and that each shell area can be matched to a potential donor shell by combinations of length, width, and weight. Simulations using the model show that shell reconstructions are feasible and that the size frequency can be reconstructed more accurately than the number of shells. If all fragments are preserved, shell number tends to be modestly overestimated. Assuming fragment loss, the shell number estimated will be a conservative estimate of original abundance. Reconstructed size frequencies did not differ significantly from the original size frequencies of the whole shells even if 40% of the fragments were not preserved. Biovolume, consequently, may also be estimable. Standardly, bivalve fragments are enumerated by counting intact umbos. If all fragments are preserved, this approach is preferable, as shell model reconstructions overestimate abundance under that circumstance. However, the expectation that fragments with intact umbos are uniquely well preserved is unrealistic and if fragment loss has occurred, relying on all fragments may provide an improved estimate of the original abundance and, in addition, an estimate of the size frequency and the latter proves to be robust even with 40% of the fragments lost.

Ecophenotypic plasticity in shell growth direction of asari clam Ruditapes philippinarum

2021 ◽  
pp. 1-6
Author(s):  
Takeshi Tomiyama
Keyword(s):  
Growth Rate ◽  
Shell Growth ◽  
Shell Height ◽  
Growth Direction ◽  
Ruditapes Philippinarum ◽  
Shell Morphology ◽  
Individual Growth ◽  
Shell Size ◽  
Internal Factors ◽  
Suitable Habitats

Abstract Asari clam (or Manila clam) Ruditapes philippinarum is an important bivalve for local fisheries. This species exhibits a large variation in shell morphology, and the shell roundness tends to be greater in more unsuitable habitats. To test whether the increments in shell size parameters (length, height and width) were affected solely by environmental conditions or by internal factors such as initial shell shapes or growth rate, a field caging experiment was conducted at two different sites of unsuitable and suitable habitats in Matsukawaura Lagoon, Japan, where shell shapes of wild clams were significantly different between the habitats. In the experiment, clams were released from the two sites to the same site or to the other site and were re-collected after 3, 6 and 12 months of caging. Caged clams originating from unsuitable habitats and released to suitable habitats showed a reduction in shell height relative to shell length, while clams from suitable habitats introduced to unsuitable habitats showed marked increases in both shell height and width. Generalized linear mixed models suggested that the increase in shell height was affected largely by the release habitat (environment) whereas the increase in shell width was affected largely by the individual growth rate. These results suggest that marginal growths in shell height and width respond differently to external and internal factors of clams, resulting in plasticity in their shell shapes according to the environments to which they are translocated.

Precise Temporal Correlation of Holocene Mollusk Shells Using Sclerochronology

2000 ◽  
Vol 53 (2) ◽  
pp. 236-246 ◽  
Author(s):  
Thomas M. Marchitto ◽  
Glenn A. Jones ◽  
Glenn A. Goodfriend ◽  
Christopher R. Weidman
Keyword(s):  
Shell Growth ◽  
Morphological Characteristics ◽  
Temporal Correlation ◽  
Band Width ◽  
Georges Bank ◽  
Arctica Islandica ◽  
Mollusk Shells ◽  
Aspartic Acid Racemization ◽  
Geochemical Proxies ◽  
Growth Bands

AbstractAnnual growth bands of mollusk shells record several types of paleoenvironmental information, including geochemical proxies for water properties and morphological characteristics of growth and mortality. Sclerochronology, the marine counterpart of dendrochronology, offers a way to link individual shells together to form long continuous records of such parameters. It also allows for precise dating of recent shells and identification of contemporaneous fossil individuals. The longevity of the ocean quahog Arctica islandica (commonly >100 yr) makes this species well suited for sclerochronology. Band width records of contemporaneous A. islandica specimens from the same region exhibit high correlations (ρ = 0.60–0.80 for spans of ≥30 bands), indicating some common environmental influences on shell growth. By adopting several strict criteria, fossil (dead-collected) shells can be linked into composite sclerochronologies. A seven-shell 154-yr chronology was constructed for Georges Bank using three live-collected and four dead-collected shells. Band width matching indicates that the dead-collected individuals died in A.D. 1950, 1971, 1978, and 1989. Sclerochronological age assignments were verified using aspartic acid racemization dating. Construction of a 1000-yr sclerochronology is judged to be feasible using the described methods.

Evidence of long and discontinuous juvenile periods in Trillium catesbaei under contrasting levels of herbivory

Botany ◽  
2014 ◽  
Vol 92 (1) ◽  
pp. 77-81 ◽  
Author(s):  
Christopher R. Webster ◽  
Michael A. Jenkins
Keyword(s):  
Life History ◽  
Reproductive Success ◽  
Age Structure ◽  
Morphological Characteristics ◽  
Population Viability ◽  
Plant Age ◽  
Life History Stage ◽  
Structure And Morphology ◽  
Single Leaf ◽  
Poor Indicator

We investigated the influence of chronic herbivory by white-tailed deer (Odocoileus virginianus (Zimmermann, 1780)) on the age structure and morphology of Trillium catesbaei Elliott. At sites with contrasting histories of deer abundance (Cades Cove, high; Whiteoak Sink, low), we measured morphological characteristics and determined minimum plant age for 60 plants (30 per site) in the single-leaf life-history stage. We chose this stage because its presence is considered an indication of successful reproduction by the previous generation, but its value could be inflated if plants regress or remain in this stage for extended periods. Our results suggest that T. catesbaei may spend upwards of a decade in this stage. Cades Cove single leaves were significantly older (p = 0.011) than those at Whiteoak Sink. Rhizome recession (decay of the oldest portion) was more common at Cades Cove, suggesting greater regression to this stage from three-leaf stages. Although minimum plant age was significantly associated with vegetative attributes (p < 0.002) at Whiteoak Sink, these attributes were decoupled at Cades Cove (p ≥ 0.642). Collectively, our results suggest that chronic herbivory may lead to a long and regressive residency period in the single-leaf stage. Consequently, in Trillium populations heavily impacted by deer, the number of single-leaf plants may be a poor indicator of reproductive success and population viability.

scholarly journals Do we have infraspecific taxa of Salvia multicaulis Vahl. (Lamiaceae) in Iran?

2017 ◽  
Vol 7 (4) ◽  
pp. 432-439 ◽  
Author(s):  
Seyed Mehdi Talebi ◽  
Reza Rezakhanlou ◽  
A V. Matsyura
Keyword(s):  
Leaf Shape ◽  
Morphological Characteristics ◽  
Leaf Length ◽  
Width Ratio ◽  
Petiole Length ◽  
Widespread Species ◽  
Basal Leaf ◽  
Leaf Petiole ◽  
Upgma Cluster Analysis ◽  
Length Width

<p><em>Salvia multicaulis</em> is a widespread species of Lamiaceae family in Iran. There are many discussions about its infraspecific variations. Although some varieties were definite for this species in various parts of the world, no infraspecific taxon was reported in Iran and all samples of this species were named as S. multicaulis. In this study, morphological characteristics of S. multicaulis populations, naturally growing in Iran, was examined. Twenty-two traits were examined in 94 individuals of this species to<br />identify their phenotypic difference. Most of the investigated features were showing a high degree of variability, but it was highly pronounced for some characteristics such as basal leaf shape, basal leaf width, basal leaf length/ width ratio and basal petiole length. Significant positive/negative correlations were observed between some morphological variables. Furthermore, significant negative correlations were found between the eastern distribution of populations with basal leaf petiole length and basal leaf length/ width ratio. Based on the UPGMA cluster analysis, populations were divided into two main branches. The first branch contained four populations, while the second branch was bigger and clustered in two sub-branches. In one of them,<br />three populations and in another one the rest populations arranged in two groups. CA joined plot confirmed that each of studied populations or group of populations had distinct morphological trait(s), which were useful in identification of them. Our findings supported population no. 13 had unique morphological traits such as the largest bracts and basal leaf petiole, highest flower number of each inflorescence cycle, widest and largest calyx. The conservation of the highly diverse populations of<br />Iranian S. multicaulis is recommended.</p>

scholarly journals Damages from extreme flooding events to cultural heritage and landscapes: water component estimation for Centa River (Albenga, Italy)

2018 ◽  
Vol 45 ◽  
pp. 389-395 ◽  
Author(s):  
Branka Cuca ◽  
Luigi Barazzetti
Keyword(s):  
River Estuary ◽  
Weather Conditions ◽  
Archaeological Site ◽  
Remote Access ◽  
Impact Monitoring ◽  
Medium Resolution ◽  
Ground Survey ◽  
Extreme Flooding ◽  
Flooded Area ◽  
Flooding Events

Abstract. The monitoring of hazardous events through change detection has an important role in the emergency management. Such actions can be performed shortly after the hazardous event for first rapid mapping but also over longer periods of time for recovery purposes and risk mapping. The use of medium resolution free-of-charge multi-spectral satellite imagery for purposes of flood extension and impact monitoring can be extremely valuable due to their ability to offer an “easy” and remote access to information, even in cases of extreme weather conditions, but also due to their high compatibility with GIS environments. The case study regards Centa River estuary that hosts an important archaeological site of Albenga within the boundaries of its riverbed. The authors propose a workflow that uses Copernicus Sentinel-2 data to provide the comparison changes firstly in the single relevant bands and successively in the indexes NDVI e NDWI, suitable for the estimation of water component. The results of this study were useful for observing the extension of the flooded area, to evaluate its impact on the archaeological remains and to further propose more targeted UAV-born and ground survey.

scholarly journals Descriptions of four new dextral land snails of the genus Camaena (Gastropoda, Eupulmonata, Camaenidae) from south China

ZooKeys ◽  
2020 ◽  
Vol 996 ◽  
pp. 37-58
Author(s):  
Pei Wang ◽  
Mei-Ling Hu ◽  
Jun-Hong Lin ◽  
Hai-Fang Yang ◽  
Xiao-Jing Li ◽  
...  
Keyword(s):  
New Species ◽  
South China ◽  
Dna Sequences ◽  
Reproductive System ◽  
Phylogenetic Analyses ◽  
Morphological Characteristics ◽  
Land Snails ◽  
Shell Morphology ◽  
Molecular Phylogenetic ◽  
Living Environments

In this study, four new dextral camaenid from China are reported, based on shell morphology, reproductive system anatomy, and molecular phylogenetic analyses: Camaena funingensis Zhou, Wang &amp; Lin, sp. nov., Camaena gaolongensis Zhou, Wang &amp; Lin, sp. nov., Camaena maguanensis Zhou, Wang &amp; Hu, sp. nov., and Camaena yulinensis Zhou, Wang &amp; Hu, sp. nov. Detailed descriptions of the morphological characteristics including shells and genitalia, DNA sequences, and living environments of the four new species are provided, with further comparisons with congeners.

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