Crassostrea virginica (eastern oyster shell) (Virginia Beach, Virginia, USA) 1 : 無料・フリー素材/写真
Crassostrea virginica (eastern oyster shell) (Virginia Beach, Virginia, USA) 1 / James St. John
| ライセンス | クリエイティブ・コモンズ 表示 2.1 |
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| 説明 | Crassostrea virginica (Gmelin, 1791) - eastern oyster shell from Virginia, USA. (external surface; ~7.7 centimeters across at its widest)Bivalves are bilaterally symmetrical molluscs having two calcareous, asymmetrical shells (valves) - they include the clams, oysters, and scallops. In most bivalves, the two shells are mirror images of each other (the major exception is the oysters). They occur in marine, estuarine, and freshwater environments. Bivalves are also known as pelecypods and lamellibranchiates.Bivalves are sessile, benthic organisms - they occur on or below substrates. Most of them are filter-feeders, using siphons to bring in water, filter the water for tiny particles of food, then expel the used water. The majority of bivalves are infaunal - they burrow into unlithified sediments. In hard substrate environments, some forms make borings, in which the bivalve lives. Some groups are hard substrate encrusters, using a mineral cement to attach to rocks, shells, or wood.The fossil record of bivalves is Cambrian to Recent. They are especially common in the post-Paleozoic fossil record.Seen here is an eastern oyster shell, Crassostrea virginica. Shell shape varies from irregularly subcircular to elongated. Oysters are sessile, benthic filter-feeders than encrust hard substrates - rocks, shells, or wood. The upper shell frequently detaches after death, while the lower shell often remains attached to the substrate. The cementing agent is the mineral calcium carbonate (CaCO3).Classification: Animalia, Mollusca, Bivalvia, Pteriomorphia, Ostreoida, OstreidaeLocality: Virginia Beach, southeastern coast of Virginia, USA----------------------More info. at:en.wikipedia.org/wiki/Eastern_oyster |
| 撮影日 | 2025-02-10 16:40:27 |
| 撮影者 | James St. John |
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