Variability in the formation and detection of growth increments in bivalve shells

Paleobiology ◽  
1980 ◽  
Vol 6 (4) ◽  
pp. 503-511 ◽  
Author(s):  
Walter W. Hughes ◽  
Conrad D. Clausen
Keyword(s):  
Computer Program ◽  
Natural Environment ◽  
Serial Correlation ◽  
Striking Similarity ◽  
Increment Width ◽  
Growth Increments ◽  
Quantitative Results ◽  
Protothaca Staminea ◽  
Bivalve Shells ◽  
Visual Observations

Growth increments in bivalve shells have been used in geophysics and paleoecology. However, little study has been given to the variability of increment patterns within and between shells. The variability of increment patterns is examined visually and quantitatively, with the help of a serial correlation computer program. Analyses of increment patterns of the bivalvesChione fluctifragaandProtothaca staminea(Veneridae) indicate that: 1) quantitative results complement the visual observations; 2) increments are not consistently detected during successive measurements; 3) a striking similarity exists between right and left valves of the same specimen; and 4) different specimens collected from the same natural environment do not show any one-to-one increment relationship—however, increment width trends may be present. The variation of increment patterns seen between specimens suggests caution in the use of bivalve increments in paleoecology.

The role of measurement error on the interpretation of otolith increment width in the study of growth in larval fish

2001 ◽  
Vol 58 (11) ◽  
pp. 2204-2212 ◽  
Author(s):  
P Pepin ◽  
J F Dower ◽  
H P Benoît
Keyword(s):  
Measurement Error ◽  
Growth Rates ◽  
Environmental Conditions ◽  
Serial Correlation ◽  
Larval Fish ◽  
Increment Width ◽  
Growth Increments ◽  
Otolith Increment ◽  
Clear Increase

Patterns in increment widths and the associated measurement error were studied in the otoliths of radiated shanny (Ulvaria subbifurcata) larvae sampled from the field. Mean increment widths increased with larval age, whereas the relative measurement error decreased. Furthermore, the level of serial correlation in increment widths showed a clear increase with age. When measurement error was taken into consideration, the pattern of serial correlation indicates that an individual's growth increments did not show the effect of changes in local environmental conditions for at least 3 days, independent of age. Only after that period can we hope to detect the effect of environmental influences on increment widths (and by inference growth rates). The patterns of measurement error and serial correlation will have direct impacts on our ability to find the influence of environmental conditions on growth rates of individual larvae and determine patterns of selective loss in a population of larval fish.

Otoliths of Chinook Salmon (Oncorhynchus tshawytscha): Daily Growth Increments and Factors Influencing Their Production

1982 ◽  
Vol 39 (10) ◽  
pp. 1340-1347 ◽  
Author(s):  
John D. Neilson ◽  
Glen H. Geen
Keyword(s):  
Chinook Salmon ◽  
Oncorhynchus Tshawytscha ◽  
Fish Length ◽  
Feeding Frequency ◽  
Otolith Growth ◽  
Increment Width ◽  
Daily Growth ◽  
Factors Affecting ◽  
Growth Increments ◽  
Otolith Increment

The effects of photoperiod, feeding frequency, and water temperature on formation of otolith daily growth increments in juvenile chinook salmon (Oncorhynchus tshawytscha) were examined. Feeding frequency influenced both increment number and width, whereas photoperiod and temperature affected only increment width. Fish fed once/24 h produced one increment every 24 h on average, while fish fed 4 times/24 h produced more than one increment every 24 h. Wider increments were produced in fish exposed to warmer water (11 °C) or 24 h of darkness. The ratio of otolith size to fish size remained constant throughout and between the photoperiod, temperature, and feeding frequency experiments, regardless of the number or width of increments produced. Although otolith growth is isometric with respect to increase in fish length under these experimental regimes, otolith microstructure will differ in fish of the same size reared under different environmental conditions. An understanding of factors affecting otolith increment production is required before increment number and width can be used to assess growth rates.Key words: otolith, daily, growth increments, chinook salmon

scholarly journals ShellTrace v1.0 – A new approach for modelling growth and trace element uptake in marine bivalve shells: Model verification on pacific oyster shells (Crassostrea gigas)

2017 ◽  
Author(s):  
Niels J. de Winter
Keyword(s):  
Growth Rate ◽  
Trace Elements ◽  
Chemical Composition ◽  
Trace Element ◽  
Pacific Oyster ◽  
Model Verification ◽  
New Approach ◽  
Element Concentrations ◽  
Growth Increments ◽  
Bivalve Shells

Abstract. Bivalve shells record changes in their environment in the chemical composition of their shells and are frequently used as paleoclimate archives. However, many studies have shown that physiological changes related to growth of the bivalve may overprint these chemical tracers. In the present study, a new approach is presented that models growth and development of bivalve shells without a priori knowledge of the physiology of the species. The model uses digitized growth increments in a cross section of the shell together with basic assumptions of the shape of the shell in order to model changes in shell length, thickness, volume, mass and growth rate at a daily resolution through the lifetime of the bivalve. This approach reconstructs the growth history of bivalves based on their shell without the need for a culture experiment, paving the way for growth rate estimations based on fossil bivalve shells. Combination of the growth model with 2D X-Ray Fluorescence trace element mapping allows the incorporation of trace elements into the shell to be modelled in 3D through the bivalve's lifetime. This approach yields records of integrated total-shell trace element concentrations and accumulation rates, which shed light on the rates and mechanisms by which these trace elements are incorporated into the shells of bivalves. Application of growth and trace element modelling on a set of modern pacific oyster shells of well-known origin and comparison of model results with conventional trace element transects highlights the importance of considering heterogeneity in mineralogy, mineralization rates and chemical composition within the shells of bivalves. These insights lead to a better understanding of the complexity of trace element concentrations in bivalve shells, which can then be applied as proxies for the reconstruction of sub-annual changes in palaeoenvironmental conditions over geological timescales.

scholarly journals Echolocation inter-click interval variation among specific behaviours in free-ranging bottlenose dolphins from the coast of Uruguay

2020 ◽  
Vol 21 (1) ◽  
pp. 141-149
Author(s):  
Javier Tellechea
Keyword(s):  
Natural Environment ◽  
Protected Area ◽  
Marine Protected Area ◽  
Bottlenose Dolphins ◽  
Acoustic Monitoring ◽  
Passive Acoustic Monitoring ◽  
Passive Acoustic ◽  
Free Ranging ◽  
Visual Observations

To assess whether behaviour can be inferred from echolocation trains (inter-click intervals) this study examines acoustic recordings of free-ranging bottlenose dolphins using Passive Acoustic Monitoring (PAM). Inter-click intervals from 17 groups of free-ranging bottlenose dolphins were monitored over a 36 day period in an area within the Cerro Verde (Marine Protected Area), Uruguay. Simultaneous visual observations were made from shore nearby. Results show that inter-click intervals in the echolocation trains had significant differences for three specific behaviours: feeding, socialising and travelling. The natural environment was quiet, with no disturbances in the immediate vicinity from boats, drones or other man-made noises.

Microstructural growth patterns in the otoliths of larval and juvenile starry flounder, Platichthys stellatus

1984 ◽  
Vol 62 (8) ◽  
pp. 1507-1512 ◽  
Author(s):  
Steven E. Campana
Keyword(s):  
Growth Rates ◽  
Larval Growth ◽  
Light And Electron Microscopy ◽  
Growth Patterns ◽  
Curvilinear Relationship ◽  
Juvenile Growth ◽  
Increment Width ◽  
Fish Size ◽  
Growth Increments ◽  
Platichthys Stellatus

Microstructural growth patterns were examined and interpreted in the otoliths of both wild and laboratory-reared starry flounders, Platichthys stellatus. Growth increments were not formed with a daily periodicity in laboratory-reared larvae. However, increment counts increased with the degree of sample preparation, suggesting that increments near the resolving limit of light microscopy were not being observed. Increments in wild flounder sagittae were more clearly defined under both light and electron microscopy; in addition, larval and juvenile growth patterns could be easily differentiated. A transition zone between the growth regions corresponded to the size and age at metamorphosis. An increase of increment width with larval age resulted from a curvilinear relationship between otolith diameter and fish size. Larval growth rates of wild fish remained relatively constant at 0.25 mm/day until metamorphosis; juvenile growth rates were substantially higher. Metamorphosis was characterized by a sudden but temporary decline in growth rate.

Interpretation of statolith microstructure in reared hatchling paralarvae of the squid Illex argentinus

2004 ◽  
Vol 55 (4) ◽  
pp. 403 ◽  
Author(s):  
Mitsuo Sakai ◽  
Norma Brunetti ◽  
Marcela Ivanovic ◽  
Beatriz Elena ◽  
Kazuyoshi Nakamura
Keyword(s):  
Full Range ◽  
Increment Width ◽  
Daily Growth ◽  
Daily Increments ◽  
Growth Increments ◽  
Absorption Phase ◽  
Yolk Absorption ◽  
Different Temperatures ◽  
Illex Argentinus ◽  
Two Phases

To identify sub-daily or aperiodic increments of statolith growth in the ommastrephid squid Illex argentinus, we examined statolith microstructure, especially with regard to the natal ring, where counting of daily growth increments should begin, and the widths of subsequent daily increments. Paralarvae obtained by artificial fertilisation were incubated on board at different temperatures ranging from 11.4 to 25.4°C, and were starved throughout the experiments. We observed statolith growth from newly hatched to 10-day-old paralarvae and used alizarine complexone staining to attempt validation of the growth. The maximum statolith radius (MSR) of newly hatched paralarvae was constant at 21.1 μm across the full range of temperatures, with the exception of 25.4°C. Daily growth of MSR was analysed separately in two phases, the pre-yolk-absorption phase (i.e. yolk sac still present) and the post-yolk-absorption phase. During the pre-yolk-absorption phase, the daily growth rate (DGR, y) of the MSR varied from 3 to 7 μm day–1 depending on rearing temperature (x) and was expressed as y = 0.37x – 1.77. We concluded that the natal ring forms at 21 μm MSR. The initial increment width obtained from the DGR of MSR seems applicable for distinguishing daily rings from sub-daily rings, although this application should be limited to hatchling paralarvae in the pre-yolk-absorption phase.

scholarly journals Here are the polyps: in situ observations of jellyfish polyps and podocysts on bivalve shells

PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e9260 ◽  
Author(s):  
Lodewijk van Walraven ◽  
Judith van Bleijswijk ◽  
Henk W. van der Veer
Keyword(s):  
North Sea ◽  
Natural Environment ◽  
Morphological Characteristics ◽  
Dogger Bank ◽  
The North ◽  
Polyp Stage ◽  
In Situ Observations ◽  
Hard Substrates ◽  
Bivalve Shells

Most Scyphozoan jellyfish species have a metagenic life cycle involving a benthic, asexually reproducing polyp stage and a sexually reproducing medusa stage. Medusae can be large and conspicuous and most can be identified using morphological characteristics. Polyps on the other hand are small, live a cryptic life attached to hard substrates and often are difficult or impossible to distinguish based on morphology alone. Consequently, for many species the polyp stage has not been identified in the natural environment. We inspected hard substrates in various habitats for the presence of Scyphozoan polyps. Three polyps were found on Dogger Bank, Central North Sea, attached to the inside of the umbo of empty valves of the bivalves Mactra stultorum and Spisula subtruncata. One polyp was accompanied by four podocysts. With this knowledge, the inside of bivalve shells washed ashore in Oostende (Belgium) was inspected and supposed podocysts on the inside of empty valves of Cerastoderma edule and Spisula elliptica were found. Polyps and podocysts were identified to species level by 18S rDNA and mitochondrial COI sequencing. The three polyps found on Dogger Bank all belonged to the compass jellyfish Chrysaora hysoscella. One podocyst from the Oostende beach also belonged to this species but another podocyst belonged to Cyanea lamarkii. These are the first in situ observations of C. hysoscella and C. lamarckii polyps and podocysts in the natural environment. Mactra, Cerastoderma and Spisula species are abundant in many North Sea regions and empty bivalve shells could provide an abundant settling substrate for jellyfish polyps in the North Sea and other areas. Several new strategies to increase the detection of polyps on bivalve shells are presented.

The morphology and ultrastructure ofBrevigraptus quadrithecatusn. gen., n. sp. (Diplograptacea), and Its convergence uponDicaulograptus hystrix(Bulman)

1988 ◽  
Vol 62 (3) ◽  
pp. 448-463 ◽  
Author(s):  
Charles E. Mitchell
Keyword(s):  
Striking Similarity ◽  
New Taxon ◽  
Cortical Tissue ◽  
Upper Ordovician ◽  
The Third ◽  
Growth Increments ◽  
South Central

Rhabdosomes ofBrevigraptus quadrithecatusn. gen., n. sp. (Lasiograptinae, Diplograptacea), from the Upper Ordovician Viola Springs Formation of south-central Oklahoma, comprise four fully developed thecae. The sicula and the first two thecae are fully sclerotized. The ultrastructure of the fusellum is unusually dense but is overlaid by a typical diplograptacean bandaged cortex. The third and fourth thecae consist of clathria covered by a cortical sheet. Lacinia are absent. The cortical sheet comprises bandages deposited in a support dominated pattern that matches expectations of the pterobranch model of peridermal secretion. Lists are fusellar derivatives and exhibit traces of fuselli-like growth increments but no continuous fusellum is present. Lists are strongly thickened with cortical tissue. The fabricational pattern employed in list construction reveals the operation of strong historical constraints during the evolutionary reduction of the fusellum.The thecal form and list architecture ofBrevigraptus quadrithecatusare nearly identical to those ofPipiograptus hesperusWhittington.Brevigraptus quadrithecatuspossesses a Pattern G astogeny and exhibits several derived astogenetic features that it shares withP. hesperusandOrthoretiolites hamiWhittington. Both thecal and astogenetic similarities suggest the new taxon is a member of the Lasiograptinae, and is closely allied to the aforementioned species.The thecae ofB. quadrithecatusexhibit striking similarity withDicaulograptus hystrix(Bulman). However, both the details of thecal construction and primordial astogeny differ markedly between these species. The thecal similarities appear to be convergent. Accordingly,D. hystrixis probably not closely allied to the Lasiograptinae.

Random isn't real: How the patchy distribution of ecological rewards may generate “incentive hope”

2019 ◽  
Vol 42 ◽  
Author(s):  
Laurel Symes ◽  
Thalia Wheatley
Keyword(s):  
Natural Environment ◽  
Random Distribution ◽  
Spatiotemporal Distribution ◽  
Patchy Distribution ◽  
Distribution Of Resources

AbstractAnselme & Güntürkün generate exciting new insights by integrating two disparate fields to explain why uncertain rewards produce strong motivational effects. Their conclusions are developed in a framework that assumes a random distribution of resources, uncommon in the natural environment. We argue that, by considering a realistically clumped spatiotemporal distribution of resources, their conclusions will be stronger and more complete.

Extreme self-sacrifice beyond fusion: Moral expansiveness and the special case of allyship

2018 ◽  
Vol 41 ◽  
Author(s):  
Daniel Crimston ◽  
Matthew J. Hornsey
Keyword(s):  
General Theory ◽  
Biological Markers ◽  
Natural Environment ◽  
Relevant Dimension ◽  
Special Case

AbstractAs a general theory of extreme self-sacrifice, Whitehouse's article misses one relevant dimension: people's willingness to fight and die in support of entities not bound by biological markers or ancestral kinship (allyship). We discuss research on moral expansiveness, which highlights individuals’ capacity to self-sacrifice for targets that lie outside traditional in-group markers, including racial out-groups, animals, and the natural environment.

Sign in / Sign up

Export Citation Format

Share Document