Open Access. Powered by Scholars. Published by Universities.®
Articles 1 - 3 of 3
Full-Text Articles in Earth Sciences
Radiocarbon In Marine Bacteria: Evidence For The Ages Of Assimilated Carbon, J Cherrier, Je Bauer, Et Al
Radiocarbon In Marine Bacteria: Evidence For The Ages Of Assimilated Carbon, J Cherrier, Je Bauer, Et Al
VIMS Articles
It is generally accepted that marine bacteria utilize labile, recently produced components of bulk dissolved organic matter. This interpretation is based largely on indirect measurements using model compounds and plankton-derived organic matter. Here, we present an assessment of the relative proportions of modem and older dissolved organic carbon (DOC) utilized by marine bacteria. Bacterial nucleic acids were collected from both estuarine (Santa Rosa Sound, FL) and open-ocean (eastern North Pacific) sites, and the natural radiocarbon signatures of the nucleic acid carbon in both systems were determined. Bacterial nucleic acids from Santa Rosa Sound were significantly enriched in radiocarbon with respect …
Limitation Of Algal Growth By Iron Deficiency In The Australian Subantarctic Region, Peter N. Sedwick, Giacomo R. Ditullio, David A. Hutchins, Philip W. Boyd, F. Brian Griffiths, A. Clive Crossley, Thomas W. Trull, Bernard Queguiner
Limitation Of Algal Growth By Iron Deficiency In The Australian Subantarctic Region, Peter N. Sedwick, Giacomo R. Ditullio, David A. Hutchins, Philip W. Boyd, F. Brian Griffiths, A. Clive Crossley, Thomas W. Trull, Bernard Queguiner
OES Faculty Publications
In March 1998 we measured iron in the upper water column and conducted iron- and nutrient-enrichment bottle-incubation experiments in the open-ocean Subantarctic region southwest of Tasmania, Australia. In the Subtropical Convergence Zone (∼42°S, 142°E), silicic acid concentrations were low (< 1.5μM) in the upper water column, whereas pronounced vertical gradients in dissolved iron concentration (0.12-0.84 nM) were observed., presumably reflecting the interleaving of Subtropical and Subantarctic waters, and mineral aerosol input. Results of a bottle-incubation experiment performed at this location indicate that phytoplankton growth rates were limited by iron deficiency within the iron-poor layer of the euphotic zone. In the Subantarctic water mass (∼46.8°S, 142°E), low concentrations of dissolved iron (0.05-0.11nM) and silicic acid (< 1μM) were measured throughout the upper water column, and our experimental results indicate that algal growth was limited by iron deficiency. These observations suggest that availability of dissolved iron is a primary factor limiting phytoplankton growth over much of the Subantarctic Southern Ocean in the late summer and autumn.
A Biogeochemical Comparison Of Fossil (Carboniferous) And Modern Crustose Red Algae, Michael A. Kruge, John E. Utgaard, William Ferry
A Biogeochemical Comparison Of Fossil (Carboniferous) And Modern Crustose Red Algae, Michael A. Kruge, John E. Utgaard, William Ferry
Department of Earth and Environmental Studies Faculty Scholarship and Creative Works
The nature of the contribution of the various types of algae to sedimentary organic matter continues to be a topic of research interest. Crustose red algae have however received less attention than other types. The fossil calcareous red algae (Rhodophyta) analyzed in this study are two relatively unrecrystallized specimens of Parachaetetes (Family Solenoporacea) from the lower part of the Ste. Genevieve Formation (Carboniferous, Visean) in Union County, Illinois, USA. They occurred in the patch reef phase of a small carbonate mudmound-patchreef. The three modern specimens (collected and identified by F. Collier) are the crustose algae Lithothamnion, Clathromorphum and Phymatolithon …