Siliceous sponges

Figure 2.8 Reconstruction of a Middle Cambrian sea floor about 600,000,000 years ago. The fauna includes siliceous sponges (the upright cones), jellyfish, and two genera of trilobites (Paradoxides, the large form, and Eliipsocephalus, the small form). Bacteria had probably already been in existence for millions of years.

Some of the aformentioned analytical difficulties have largely been overcome in a recent study on a selected group of diatoms and siliceous sponges, and the results are briefly summarized548) ... 

Table 10. Distribution of amino acids (residues/1000) in cell contents and cell walls of 6 species of diatoms from various habitats. Column a distribution in cell contents Column b cell walls. Bottom of table emphasizes the difference (Column b - Column a) between cell-wall composition and cell contents for those amino acids which show consistent trends. The sponge spicules are from Ctiona celata, and the sponge tissue is from an unidentified siliceous sponge. AA amino acids HA hexosamines... 

Amino acids Navicula pelliculosa a b Melosira nummuloides a b Melosira granulata a b Cyclotella stelligera a b Cyclotella cryptica a b Nitzschia brevirostris a b Siliceous sponge Tissue Spicule ... 

Schwab, D. W, and Shore, R. E. Fine structure and composition of a siliceous sponge spicule. Biol. Bull. 140, 125-136 (1971). 

Brunton, F. R. and Dixon, O. A., Siliceous sponge-microbe biotic associations and their recurrence through the Phanerozoic as reef mound constructors, Palaios, 9, 370, 1994. 

Maldonado, M., Carmona, M., Velasquez, Z., Puig, A., Cruzado, A., Lopez, A., and Yotmg, C. (2005). Siliceous sponges as a silicon sink An overlooked aspect of henthopelagic coupling in the marine sihcon cycle. Limnol. Oceanogr. 50, 799—809. 

Figure 1 Diatoms are one of the most abundant biota containing siliceous skeletal material in the marine environment. Radiolaria, silicoflagellates, and siliceous sponges also deposit this amorphous phase for structural support. The diatoms in the figure (Corethron sp.) were collected from the Antarctic continental shelf, occurring as a monotypic assemblage in a large phytoplankton bloom. The siliceous frustules in this figure t3fpically are 100-...

More recently, another purine—spongopurine (23)—isolated from a giant siliceous sponge (family Ocodia.y has been identified as l-methyladenine. This purine probably resulted from the hydrolysis (during the isolation procedure) of... 

As mentioned above, the primary biota that construct siliceous skeletons are diatoms, radiolaria, silicoflagellates, and siliceous sponges. Diatoms are marine algae. These phytoplankton account for 20-40% of the primary production in the ocean and an even greater percentage of the export production... 

Silicate is a very important nutrient in the ocean. Unlike other major nutrients such as phosphate and nitrate or ammonium, which are needed by almost all marine plankton, silicate is an essential chemical only for certain biota such as diatoms, radiolarian, sihcoflageUates, and siliceous sponges. However, this biology is one of the most important producers in marine. The estimation shows that diatoms contribute more than 40% of the entire primary production. Therefore, silicate cycling has received significant scientific attention in recent years and many scientists have studied silicate behavior in marine environments. Biogenic silicate is the amorphous content extracted by chemical methods, which is named as biogenic opal or opal in brief. The concentration of dissolved silicate in the world ocean is about 70.6 pmol/L and the net input of dissolved silicate from land to ocean is (6.1 2.0)x 10 mol (calculated by Si) every year, and the primary contribution (about 80%) comes from river. 

Silicon is a major constituent of diatoms, which form a large proportion of marine phytoplankton. Some other algae, fungi and the siliceous sponges also have structural parts consisting of silica. The diatoms and radiolaria can excrete silica in the form of opal (amorphous silica, Si02 WH2O). 

Biosilica The enzymatically formed scaffold of siliceous sponge spicules... 

The formation of the skeletal system from the earliest metazoans, the sponges (phylum Porifera) (Muller et al., 2(X)9a,b) to the crown taxa, the mammalians (Matsuo and Irie, 2008) and the insects (Moussian, 2010), is dominated by a tuned communication between cells controlling anabolic processes and cells executing catabolic reactions. Basically, two kinds of inorganic scaffold materials had been applied in the metazoan kingdom to form skeletons calcium (calcium-based skeletal systems) and—only found in siliceous sponges—silica (silica-based skeletons). 

Muller, W.E.G., Li, J., Schroder, H.C., Qiao, L., Wang, X.H., 2007a. The unique skeleton of siliceous sponges (Porifera Hexactinellida and Demospongiae) that evolved first from the Urmetazoa during the Proterozoic a review. Biogeosciences 4, 219-232. 

Szot, K., Jonsson-Niedziolka, M., Palys, B and Niedziolka-Jonsson, J. (2011) One-step electrodeposition of carbon-silicate sponge assisted by a three-phase junction for efficient bioelectrocatalysis. Electrochem. Commun., 13, 566-569. 

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