Kathleen C. Ruttenberg

Bio: Kathleen C. Ruttenberg is an academic researcher from Woods Hole Oceanographic Institution. The author has contributed to research in topics: Organic matter & Total organic carbon. The author has an hindex of 9, co-authored 11 publications receiving 2360 citations.

Development of a sequential extraction method for different forms of phosphorus in marine sediments

Abstract: A sequential extraction method (SEDEX) has been developed to separately quantify five sedimentary P reservoirs: loosely sorbed P; ferric iron-bound P; authigenic carbonate fluorapatite + biogenic apatite + CaCO3-associated P; detrital apatite P; and organic P. The SEDEX method successfully separates two of the main categories of authigenic phosphate phases called upon most often as sedimentary sinks for diagenetically mobilized P: ferric oxyhydroxide-associated P and authigenic carbonate fluorapatite (CFAP). It offers a means for separating authigenic CFAP from detrital apatite of igneous or metamorphic origin. The importance of this distinction is that CFAP represents an oceanic sink for reactive P, whereas detrital apatite does not. In addition, a means for reversing secondary adsorption of P onto residual solid surfaces during extraction has been developed. Extensive standardization of the SEDEX method for application to marine sediments has been performed with analogs for naturally occurring phosphatic phases.

Sources and contribution of terrigenous organic carbon to surface sediments in the Gulf of Mexico

Abstract: The sources and burial processes of organic matter in marine sediments are not well understood, yet they are important if we are to have a better understanding of the global carbon cycle1. In particular, the nature and fraction of the terrestrial organic carbon preserved in marine sediments is poorly constrained. Here we use the chemical and stable carbon isotope signatures of oxidation products from a macromolecular component (lignin)2 of the terrigenous organic matter preserved in offshore surface sediments in the Gulf of Mexico to complement similar data from an existing onshore transect3 in this region. The complete onshore–offshore data set, along with radiocarbon dates of the bulk organic material at the same sites, allows the differentiation of material originating from plants that photosynthesize using the C4 mechanism from those that undergo C3 photosynthesis. We conclude that the offshore lignins derive from erosion of the extensive grassland (C4) soils of the Mississippi River drainage basin, and that the nearshore lignins originate largely from C3 plant detritus from coastal forests and swamps. This distribution is probably due to the hydrodynamic sorting of the different source materials4 during their seaward transport. These results suggest that previous studies3,5 have significantly underestimated the terrigenous fraction of organic matter in offshore sediments by not recognizing the contribution of C4 vegetation to the carbon-isotope composition. Such an underestimate may force revisions in the assessment of past marine primary productivity and associated organic carbon fluxes6, and of organic matter preservation/remineralization7 and nutrient cycling8 in marine sediments.

Preservation of organic matter in marine sediments: controls, mechanisms, and an imbalance in sediment organic carbon budgets?

Abstract: The burial of organic matter (OM) in marine sediments represents the major link between “active” surface pools of carbon in the oceans, atmosphere, on land, and in marine sediment, and carbon pools that cycle on much longer, geologic time scales (i.e., carbon in sedimentary rock, coal, and petroleum deposits). It also plays some role in controlling atmospheric CO2 and O2 on these long time scales because in a highly simplified fashion OM burial in sediments can be thought of in terms of the balance between primary production and respiration on land and in the oceans.