Topic
Sponge spicule
About: Sponge spicule is a research topic. Over the lifetime, 1055 publications have been published within this topic receiving 25365 citations. The topic is also known as: Sponge spicule.
Papers published on a yearly basis
1 / 2
Papers
TL;DR: The structural properties of biosilica observed in the hexactinellid sponge Euplectella sp.
Abstract: Structural materials in nature exhibit remarkable designs with building blocks, often hierarchically arranged from the nanometer to the macroscopic length scales. We report on the structural properties of biosilica observed in the hexactinellid sponge Euplectella sp. Consolidated, nanometer-scaled silica spheres are arranged in well-defined microscopic concentric rings glued together by organic matrix to form laminated spicules. The assembly of these spicules into bundles, effected by the laminated silica-based cement, results in the formation of a macroscopic cylindrical square-lattice cagelike structure reinforced by diagonal ridges. The ensuing design overcomes the brittleness of its constituent material, glass, and shows outstanding mechanical rigidity and stability. The mechanical benefits of each of seven identified hierarchical levels and their comparison with common mechanical engineering strategies are discussed.
1,112 citations
TL;DR: It is shown that an additional mineral phase, amorphous calcium carbonate, is present in the sea urchin larval spicule, and that this inherently unstable mineral transforms into calcite with time.
Abstract: Sea urchin larvae form an endoskeleton composed of a pair of spicules. For more than a century it has been stated that each spicule comprises a single crystal of the CaCO3 mineral, calcite. We show...
726 citations
TL;DR: In this article, high-resolution observations of the Sun in Ca II H (3968A) from the Solar Optical Telescope on Hinode were used to show that there are at least two types of spicules that dominate the structure of the magnetic solar chromosphere.
Abstract: We use high-resolution observations of the Sun in Ca II H (3968A) from the Solar Optical Telescope on Hinode to show that there are at least two types of spicules that dominate the structure of the magnetic solar chromosphere. Both types are tied to the relentless magnetoconvective driving in the photosphere, but have very different dynamic properties. “Type-I” spicules are driven by shock waves that form when global oscillations and convective flows leak into the upper atmosphere along magnetic field lines on 3-7 minute timescales. “Type-II” spicules are much more dynamic: they form rapidly (in ∼10s), are very thin (≤200km wide), have lifetimes of 10-150s (at any one height) and seem to be rapidly heated to (at least) transition region temperatures, sending material through the chromosphere at speeds of order 50-150 km/s. The properties of Type II spicules suggest a formation process that is a consequence of magnetic reconnection, typically in the vicinity of magnetic flux concentrations in plage and network. Both types of spicules are observed to carry Alfven waves with significant amplitudes of order 20 km/s.
502 citations
TL;DR: The fauna indicates that animals lived 40 to 50 million years before the Cambrian Explosion, and the presence of possible amphiblastula larva suggests that the calcareous sponges may have an extended history in the Late Precambrian.
Abstract: Sponge remains have been identified in the Early Vendian Doushantuo phosphate deposit in central Guizhou (South China), which has an age of approximately 580 million years ago. Their skeletons consist of siliceous, monaxonal spicules. All are referred to as the Porifera, class Demospongiae. Preserved soft tissues include the epidermis, porocytes, amoebocytes, sclerocytes, and spongocoel. Among thousands of metazoan embryos is a parenchymella-type of sponge larvae having a shoe-shaped morphology and dense peripheral flagella. The presence of possible amphiblastula larva suggests that the calcareous sponges may have an extended history in the Late Precambrian. The fauna indicates that animals lived 40 to 50 million years before the Cambrian Explosion.
483 citations
TL;DR: In this article, high-resolution observations of the Sun in Ca II H 3968 A from the Solar Optical Telescope on Hinode were used to show that there are at least two types of spicules that dominate the structure of the magnetic solar chromosphere.
Abstract: We use high-resolution observations of the Sun in Ca II H 3968 A from the Solar Optical Telescope on Hinode to show that there are at least two types of spicules that dominate the structure of the magnetic solar chromosphere. Both types are tied to the relentless magnetoconvective driving in the photosphere, but have very different dynamic properties. ``Type-I'' spicules are driven by shock waves that form when global oscillations and convective flows leak into the upper atmosphere along magnetic field lines on 3-7 minute timescales. ``Type-II'' spicules are much more dynamic: they form rapidly (in ~10s), are very thin (<200km wide), have lifetimes of 10-150s (at any one height) and seem to be rapidly heated to (at least) transition region temperatures, sending material through the chromosphere at speeds of order 50-150 km/s. The properties of Type II spicules suggest a formation process that is a consequence of magnetic reconnection, typically in the vicinity of magnetic flux concentrations in plage and network. Both types of spicules are observed to carry Alfven waves with significant amplitudes of order 20 km/s.
326 citations
Related Topics (5)
Performance Metrics
| Year | Papers |
|---|---|
| 2025 | 59 |
| 2024 | 97 |
| 2023 | 118 |
| 2022 | 258 |
| 2021 | 189 |
| 2020 | 68 |