geoscience.net logo
+ Resolve Article
+ Follow Us
Follow on FacebookFollow on Facebook
Follow on TwitterFollow on Twitter

+ Translate
+ Subscribe to Site Feed
GeoScience Most Shared ContentMost Shared Content

How dysaerobic is the dysaerobic zone?


, : How dysaerobic is the dysaerobic zone?. Geological Society of America 42.5

The dysaerobic biozone is broadly defined by deposition under conditions of less than normal oxygen levels. Although precise oxygen levels are not typically quantified from the rock record, reduced oxygen conditions are largely recognized by the preserved biological signal, as metazoan life is very sensitive to fluctuations in bottom water oxygen levels. Dysoxic, or reduced oxygen conditions are common in the rock record, but potentially represent a large range of relative oxygen levels between anoxic and fully oxygenated, as well as a broad spectrum of depositional settings. Devonian aged black shales from localities across the Appalachian Basin representing deposition in a broad shallow epeiric sea were sampled at high resolution to investigate the dynamics of the dysaerobic zone. Sampled intervals were selected to represent a range of relative oxygen levels through the dysaerobic zone. Using a combined trace and body fossil approach, including relative amount of bioturbation, burrow size, and species richness, variations in relative oxygen are recognized on the sub-cm scale. These results reveal that intervals broadly defined as dysaerobic based on low macrofaunal and trace fossil diversity, and low to moderate bioturbation are not temporally stable. No intervals greater than 3 cm in thickness that recorded stable dysoxic conditions were identified. It is likely that the dysaerobic zone represents conditions of changing bottom water oxygen levels, commonly fluctuating rapidly between anoxic and dysoxic, rather than persistent dysoxic conditions. These findings have important implications for understanding oceanographic dynamics of ancient epeiric seaways.

US$29.90


Other references

Segalowitz S.J.; Ogilvie R.D., 1991: Event related potential evidence of information processing at the onset of and during sleep. International Journal of Clinical & Experimental Hypnosis 39(4): 270

Muller, F.; Strack, E.; Reinhold, H., 1963: The influence of infusion of fructose and phosphate on the level of the inorganic phosphates of the blood. Rabbits served as experimental animals. The solutions were infused by catheter sealed in the duodenum and the portal vein. Ethylene diaminetetraacetic acid [EDTA] and its Ca and Mg complexes were infused enterally. Infusion of fructose depressed t...

Cornetz, V., 1911: Le phenomene du replacement de l'axe du corps chez les Fourmis. Compte Rendu de la Societe de Biologie Paris, 70 439-441

Lefkovits, I.; Burger, M., 1965: Latent -galactosidase in Escherichia coli. Incubation of washed E. coli cells with crystalline RNase increases [beta]-galactosidase activity. The increase depends on the type of strain and the conditions of cultivation. RNase only increased the level of the [beta]-galactosidase bound to th...

Virat, M.F.ublee, V., 1980: Abortions of fungal etiology in cows. Bulletin des GTV Groupements techniques veterinaires Dossiers techniques veterinaires: (3) 57-62

Berger, VJa., 1987: Methodological aspects of the studing the adaptive phenomena. Trudy Zoologicheskogo Instituta, 160: 13-30

Magnus, I.A.; Thompson, R.H., 1956: Cholinesterase levels in the skin in cholinogenic urticaria and pruritus. British Journal of Dermatology 68(9): 283-289

Kan'shina, N.F.; Darovskil, B.P., 1967: Morphology of various portions of a nephron in acute renal insufficiency caused by some nephrotoxic poisons. Changes resulting in the kidneys from poisoning with agents containing ethylene glycol were compared with renal lesions following hypoxia during a surgical operation. In the former case the convoluted tubules were affected the most, especially the...

Miyashita, H.; Hakamata, Y.; Kobayashi, E.; Kobayashi, K., 2004: Characterization of hair follicles induced in implanted, cultured rat keratinocyte sheets. Cultured rat keratinocyte sheets form hair follicles in combination with rat vibrissa dermal papillae when they are transplanted subcutaneously in syngeneic rats and athymic mice. In the present study, the histologic details of these induced folli...

Bond T.A., 1965: Ephedran pollen grains in Pleistocene sediments of central and southeastern Oklahoma. Ephedran pollen, of unknown origin, occurs in Pleistocene clay in terrace deposits of the Washita and Red Rivers. These grains do not resemble living forms which are pictured with them. They are found in association with Cretaceous-Tertiary hystri...