scholarly journals A stable ultrastructural pattern despite variable cell size in <i>Lithothamnion corallioides</i>

2021 ◽  
Vol 18 (22) ◽  
pp. 6061-6076
Author(s):  
Valentina Alice Bracchi ◽  
Giulia Piazza ◽  
Daniela Basso
Keyword(s):  
Growth Rate ◽  
Cell Walls ◽  
Environmental Variables ◽  
Coralline Algae ◽  
Ultrastructural Changes ◽  
Depth Range ◽  
Crystal Shape ◽  
Axis Parallel ◽  
Calcification Process ◽  
Early Alteration

Abstract. Recent advances on the mechanism and pattern of calcification in coralline algae led to contradictory conclusions. The evidence of a biologically controlled calcification process, resulting in distinctive patterns at the scale of family, was observed. However, the coralline calcification process has been also interpreted as biologically induced because of the dependency of its elemental composition on environmental variables. To clarify the matter, five collections of Lithothamnion corallioides from the Atlantic Ocean and the Mediterranean Sea, across a wide depth range (12–66 m), have been analyzed for morphology, anatomy and cell wall crystal patterns in both perithallial and epithallial cells to detect possible ultrastructural changes. L. corallioides shows the alternation of tiers of short-squared and long-ovoid/rectangular cells along the perithallus, forming a typical banding. The perithallial cell length decreases according to water depth and growth rate, whereas the diameter remains constant. Our observations confirm that both epithallial and perithallial cells show primary (PW) and secondary (SW) calcite walls. Rectangular tiles, with the long axis parallel to the cell membrane forming a multi-layered structure, characterize the PW. Flattened squared bricks characterize the SW, with roundish outlines enveloping the cell and showing a zigzag and cross orientation. Long and short cells have different thicknesses of PW and SW, increasing in short cells. Epithallial cells are one to three flared cells with the same shape of the PW and SW crystals. Despite the diverse seafloor environments and the variable L. corallioides growth rate, the cell walls maintain a consistent ultrastructural pattern with unaffected crystal shape and arrangement. A comparison with two congeneric species, L. minervae and L. valens, showed similar ultrastructural patterns in the SW but evident differences in the PW crystal shape. Our observations point to a biologically control rather than an induction of the calcification process in coralline algae and suggest a possible new morphological diagnostic tool for species identification, with relevant importance for paleontological applications. Finally, secondary calcite, in the form of dogtooth crystals that fill the cell lumen, has been observed. It represents a form of early alteration in living collections which can have implications in the reliability of climate and paleoclimate studies based on geochemical techniques.

scholarly journals A stable ultrastructural pattern despite variable cell size in <i>Lithothamnion corallioides</i>

2021 ◽  
Author(s):  
Valentina Alice Bracchi ◽  
Giulia Piazza ◽  
Daniela Basso
Keyword(s):  
Growth Rate ◽  
Cell Walls ◽  
Coralline Algae ◽  
Ultrastructural Changes ◽  
Depth Range ◽  
Crystal Shape ◽  
Zigzag Pattern ◽  
Axis Parallel ◽  
Calcification Process ◽  
Different Thickness

Abstract. Recent advances on the mechanism and pattern of calcification in coralline algae lead to contradictory conclusions. Coralline calcification appears biologically induced, as suggested by the dependency of its elemental composition on environmental variables. However, evidence of a biologically controlled calcification process, resulting in distinctive patterns at the scale of family, was also observed. In order to clarify the matter, five collections of Lithothamnion corallioides from the Atlantic Ocean and the Mediterranean Sea, across a wide depth range (12–66 m) have been analyzed for morphology, anatomy and cell wall crystal patterns of both perithallial and epithallial cells, in order to detect possible ultrastructural changes. L. corallioides shows the alternation of tiers of short-squared and long-ovoid/rectangular cells along the perithallus, forming a typical banding. The perithallial cell length decreases according to water depth and growth-rate, whereas diameter remains constant. Our observations confirm that both epithallial and perithallial cells show primary (PW) and secondary (SW) calcite walls. Rectangular tiles, with the long axis parallel to the cell membrane forming a multi-layered structure, characterize the PW. Flattened squared bricks characterize the SW with roundish outlines enveloping the cell and showing a zigzag pattern. Long and short cells have different thickness of PW and SW, with a thicker SW and PW in short cells. Epithallial cells are one up to three flared cells, with the same shape of the PW and SW crystals. Despite the diverse seafloor environments and the variable L. corallioides growth-rate, the cell walls maintain a consistent ultrastructural pattern, with unaffected crystal shape and arrangement. A comparison with two congeneric species, L. minervae and L. valens, showed similar ultrastructural patterns in SW, but evident differences in the PW crystal shape. Our observations point to a biological control rather than an induction of the calcification process in coralline algae, and suggest a possible new morphological diagnostic tool for species identification, with relevant importance for paleontological application. Finally, secondary calcite, in form of dogtooth crystals that fill the cell lumen, has been observed. It represents a form of early diagenesis in living collections which can have implications in the reliability of climate and paleoclimate studies based on the geochemistry techniques.

scholarly journals The influence of dynamic environmental interactions on detection efficiency of acoustic transmitters in a large, deep, freshwater lake

2019 ◽  
Vol 7 (1) ◽  
Author(s):  
Natalie V. Klinard ◽  
Edmund A. Halfyard ◽  
Jordan K. Matley ◽  
Aaron T. Fisk ◽  
Timothy B. Johnson
Keyword(s):  
Study Design ◽  
Environmental Conditions ◽  
Power Output ◽  
Environmental Variables ◽  
Acoustic Telemetry ◽  
Detection Efficiency ◽  
Data Interpretation ◽  
Heterogeneous Environments ◽  
Depth Range ◽  
Dynamic Relationship

Abstract Background Acoustic telemetry is an increasingly common method used to address ecological questions about the movement, behaviour, and survival of freshwater and marine organisms. The variable performance of acoustic telemetry equipment and ability of receivers to detect signals from transmitters have been well studied in marine and coral reef environments to inform study design and improve data interpretation. Despite the growing use of acoustic telemetry in large, deep, freshwater systems, detection efficiency and range, particularly in relation to environmental variation, are poorly understood. We used an array of 90 69-kHz acoustic receivers and 8 sentinel range transmitters of varying power output deployed at different depths and locations approximately 100–9500 m apart for 215 days to evaluate how the detection efficiency of acoustic receivers varied spatially and temporally in relation to environmental conditions. Results The maximum distance that tags were detected ranged from 5.9 to 9.3 km. Shallow tags consistently had lower detection efficiency than deep tags of the same power output and detection efficiency declined through the winter months (December–February) of the study. In addition to the distance between tag and receiver, thermocline strength, surface water velocity, ice thickness, water temperature, depth range between tag and receiver, and number of fish detections contributed to explaining variation in detection efficiency throughout the study period. Furthermore, the most significant models incorporated interactions between several environmental variables and tag–receiver distance, demonstrating the complex temporal and spatial relationships that exist in heterogeneous environments. Conclusions Relying on individual environmental variables in isolation to interpret receiver performance, and thus animal behaviour, may be erroneous when detection efficiency varies across distances, depths, or tag types. As acoustic telemetry becomes more widely used to study ecology and inform management, it is crucial to understand its limitations in heterogeneous environments, such as freshwater lakes, to improve the quality and interpretation of data. We recommend that in situ range testing and retrospective analysis of detection efficiency be incorporated into study design for telemetry projects. Furthermore, we caution against oversimplifying the dynamic relationship between detection efficiency and environmental conditions for the sake of producing a correction that can be applied directly to detection data of tagged animals when the intended correction may not be justified.

scholarly journals Effects of light and temperature on Mg uptake, growth, and calcification in the proxy climate archive <i>Clathromorphum</i> <i>compactum</i>

2018 ◽  
Vol 15 (19) ◽  
pp. 5745-5759 ◽  
Author(s):  
Siobhan Williams ◽  
Walter Adey ◽  
Jochen Halfar ◽  
Andreas Kronz ◽  
Patrick Gagnon ◽  
...  
Keyword(s):  
Sea Ice ◽  
Cell Walls ◽  
Natural Habitat ◽  
Algal Growth ◽  
High Light ◽  
Coralline Algae ◽  
Growth Increments ◽  
Environmental Controls ◽  
Wall Calcification ◽  
Ice Conditions

Abstract. The shallow-marine benthic coralline alga Clathromorphum compactum is an important annual- to sub-annual-resolution archive of Arctic and subarctic environmental conditions, allowing reconstructions going back > 600 years. Both Mg content, in the high-Mg calcitic cell walls, and annual algal growth increments have been used as a proxy for past temperatures and sea ice conditions. The process of calcification in coralline algae has been debated widely, with no definitive conclusion about the role of light and photosynthesis in growth and calcification. Light received by algal specimens can vary with latitude, water depth, sea ice conditions, water turbidity, and shading. Furthermore, field calibration studies of Clathromorphum sp. have yielded geographically disparate correlations between MgCO3 and sea surface temperature. The influence of other environmental controls, such as light, on Mg uptake and calcification has received little attention. We present results from an 11-month mesocosm experiment in which 123 wild-collected C. compactum specimens were grown in conditions simulating their natural habitat. Specimens grown for periods of 1 and 2 months in complete darkness show that the typical complex of anatomy and cell wall calcification develops in new tissue without the presence of light, demonstrating that calcification is metabolically driven and not a side effect of photosynthesis. Also, we show that both light and temperature significantly affect MgCO3 in C. compactum cell walls. For specimens grown at low temperature (2 ∘C), the effects of light are smaller, with a 1.4 mol % MgCO3 increase from low-light (mean = 17 lx) to high-light conditions (mean = 450 lx). At higher (10 ∘C) temperature there was a 1.8 mol % MgCO3 increase from low to high light. It is therefore concluded that site- and possibly specimen-specific temperature calibrations must be applied, to account for effects of light when generating Clathromorphum-derived temperature calibrations.

The role and status of Nautilus in its natural habitat: evidence from deep-water remote camera photosequences

Paleobiology ◽  
1984 ◽  
Vol 10 (4) ◽  
pp. 469-486 ◽  
Author(s):  
W. Bruce Saunders
Keyword(s):  
Growth Rate ◽  
Population Dynamics ◽  
Deep Water ◽  
Deep Sea ◽  
Natural Habitat ◽  
Normal Component ◽  
Depth Range ◽  
Reproductive Tactics ◽  
Opportunistic Predator ◽  
Remote Camera

Bottom site remote camera photosequences at depths of 73–538 m on forereef slopes in Palau show that Nautilus belauensis is a highly mobile, chemosensitive, epibenthic scavenger and opportunistic predator. The overall depth range of this species is ca. 70–500 m, but photosequences indicate a preferred range of 150–300 m. Nautilus is active both nocturnally and diurnally, locating bait sites within 1–2 h. Associated macrofauna includes caridean shrimps, crabs, and eels; teleosts are rare below 100 m, but sharks are recorded in most photosequences below 250 m. Summarily, Nautilus exhibits a combination of characters that typify deep-sea strategy, including reproductive tactics, growth rate, and population dynamics. This and other evidence suggest that fossil Nautilidae may have been deep-water forms, in contrast to the typically shallower water ammonoids, and that Nautilus is a normal component of the deep forereef rather than a late Cretaceous refugee from shallow water.

The Biology of Laminaria Hyperborea. VIII. Growth on Cleared Areas

1976 ◽  
Vol 56 (2) ◽  
pp. 267-290 ◽  
Author(s):  
Joanna M. Kain ◽  
N. S. Jones
Keyword(s):  
Growth Rate ◽  
Shallow Water ◽  
Personal Communication ◽  
Fast Growth ◽  
Depth Range ◽  
Laminaria Hyperborea ◽  
Isle Of Man ◽  
Rocky Subtidal ◽  
Small Depth

INTRODUCTIONStudies of established populations of Laminaria hyperborea (Gunn.) Fosl. have indicated that there is often less change of growth rate with depth than might be expected to result from the decrease in irradiance (Kain, 1967; Lüming, 1969; Jupp & Drew, 1974). This has been attributed to self-limitation by the canopy of Laminaria fronds (Lüning, 1969; Kain et al. 1976). The removal of this canopy can result in fast growth in shallow water (Kitching, 1941; Svendsen, 1972) and a marked differential in growth rate over a small depth range (Svendsen, personal communication). A series of rocky subtidal areas at two depths off the Isle of Man was cleared of vegetation at various times (Kain, 1975a). This provided an opportunity to make growth measurements on individuals of known age in the absence of a canopy formed by older plants.

Ozone-induced cytochemical and ultrastructural changes in leaf mesophyll cell walls

1997 ◽  
Vol 27 (4) ◽  
pp. 453-463 ◽  
Author(s):  
M S Günthardt-Georg ◽  
C J McQuattie ◽  
C Scheidegger ◽  
C Rhiner ◽  
R Matyssek
Keyword(s):  
Cell Walls ◽  
Mesophyll Cell ◽  
Ultrastructural Changes ◽  
Leaf Mesophyll ◽  
Leaf Mesophyll Cell

Ultrastructural Changes in the Cell Walls of Cambial Derivatives During Wood Formation in Indian ELM (Holoptelea Integrifolia)

IAWA Journal ◽  
2012 ◽  
Vol 33 (4) ◽  
pp. 403-416 ◽  
Author(s):  
Karumanchi S. Rao ◽  
Yoon Soo Kim ◽  
Pramod Sivan
Keyword(s):  
Cell Wall ◽  
Cell Walls ◽  
Middle Lamella ◽  
Ultrastructural Changes ◽  
Cell Wall Polysaccharides ◽  
Lignin Distribution ◽  
Parenchyma Cells ◽  
Ray Cells ◽  
Xylem Elements ◽  
S2 Layer

Sequential changes occurring in cell walls during expansion, secondary wall (SW) deposition and lignification have been studied in the differentiating xylem elements of Holoptelea integrifolia using transmission electron microscopy. The PATAg staining revealed that loosening of the cell wall starts at the cell corner middle lamella (CCML) and spreads to radial and tangential walls in the zone of cell expansion (EZ). Lignification started at the CCML region between vessels and associated parenchyma during the final stages of S2 layer formation. The S2 layer in the vessel appeared as two sublayers,an inner one and outer one.The contact ray cells showed SW deposition soon after axial paratracheal parenchyma had completed it, whereas noncontact ray cells underwent SW deposition and lignification following apotracheal parenchyma cells. The paratracheal and apotracheal parenchyma cells differed noticeably in terms of proportion of SW layers and lignin distribution pattern. Fibres were found to be the last xylem elements to complete SW deposition and lignification with differential polymerization of cell wall polysaccharides. It appears that the SW deposition started much earlier in the middle region of the fibres while their tips were still undergoing elongation. In homogeneous lignin distribution was noticed in the CCML region of fibres.

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