Sedimentary organic matter preservation: an assessment and speculative synthesis

Couplings Between Changes in the Climate System and Biogeochemistry Coordinating Lead Authors: Kenneth L. Denman (Canada), Guy Brasseur (USA, Germany) Lead Authors: Amnat Chidthaisong (Thailand), Philippe Ciais (France), Peter M. Cox (UK), Robert E. Dickinson (USA), Didier Hauglustaine (France), Christoph Heinze (Norway, Germany), Elisabeth Holland (USA), Daniel Jacob (USA, France), Ulrike Lohmann (Switzerland), Srikanthan Ramachandran (India), Pedro Leite da Silva Dias (Brazil), Steven C. Wofsy (USA), Xiaoye Zhang (China) Contributing Authors: D. Archer (USA), V. Arora (Canada), J. Austin (USA), D. Baker (USA), J.A. Berry (USA), R. Betts (UK), G. Bonan (USA), P. Bousquet (France), J. Canadell (Australia), J. Christian (Canada), D.A. Clark (USA), M. Dameris (Germany), F. Dentener (EU), D. Easterling (USA), V. Eyring (Germany), J. Feichter (Germany), P. Friedlingstein (France, Belgium), I. Fung (USA), S. Fuzzi (Italy), S. Gong (Canada), N. Gruber (USA, Switzerland), A. Guenther (USA), K. Gurney (USA), A. Henderson-Sellers (Switzerland), J. House (UK), A. Jones (UK), C. Jones (UK), B. Karcher (Germany), M. Kawamiya (Japan), K. Lassey (New Zealand), C. Le Quere (UK, France, Canada), C. Leck (Sweden), J. Lee-Taylor (USA, UK), Y. Malhi (UK), K. Masarie (USA), G. McFiggans (UK), S. Menon (USA), J.B. Miller (USA), P. Peylin (France), A. Pitman (Australia), J. Quaas (Germany), M. Raupach (Australia), P. Rayner (France), G. Rehder (Germany), U. Riebesell (Germany), C. Rodenbeck (Germany), L. Rotstayn (Australia), N. Roulet (Canada), C. Sabine (USA), M.G. Schultz (Germany), M. Schulz (France, Germany), S.E. Schwartz (USA), W. Steffen (Australia), D. Stevenson (UK), Y. Tian (USA, China), K.E. Trenberth (USA), T. Van Noije (Netherlands), O. Wild (Japan, UK), T. Zhang (USA, China), L. Zhou (USA, China) Review Editors: Kansri Boonpragob (Thailand), Martin Heimann (Germany, Switzerland), Mario Molina (USA, Mexico) This chapter should be cited as: Denman, K.L., G. Brasseur, A. Chidthaisong, P. Ciais, P.M. Cox, R.E. Dickinson, D. Hauglustaine, C. Heinze, E. Holland, D. Jacob, U. Lohmann, S Ramachandran, P.L. da Silva Dias, S.C. Wofsy and X. Zhang, 2007: Couplings Between Changes in the Climate System and Biogeochemistry. In: Climate Change 2007: The Physical Science Basis. Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change [Solomon, S., D. Qin, M. Manning, Z. Chen, M. Marquis, K.B. Averyt, M.Tignor and H.L. Miller (eds.)]. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA.

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Couplings between changes in the climate system and biogeochemistry

Occurrence, behavior and effects of nanoparticles in the environment.

The finding that total viral abundance is higher than total prokaryotic abundance and that a significant fraction of the prokaryotic community is infected with phages in aquatic systems has stimulated research on the ecology of prokaryotic viruses and their role in ecosystems. This review treats the ecology of prokaryotic viruses ('phages') in marine, freshwater and soil systems from a 'virus point of view'. The abundance of viruses varies strongly in different environments and is related to bacterial abundance or activity suggesting that the majority of the viruses found in the environment are typically phages. Data on phage diversity are sparse but indicate that phages are extremely diverse in natural systems. Lytic phages are predators of prokaryotes, whereas lysogenic and chronic infections represent a parasitic interaction. Some forms of lysogeny might be described best as mutualism. The little existing ecological data on phage populations indicate a large variety of environmental niches and survival strategies. The host cell is the main resource for phages and the resource quality, i.e., the metabolic state of the host cell, is a critical factor in all steps of the phage life cycle. Virus-induced mortality of prokaryotes varies strongly on a temporal and spatial scale and shows that phages can be important predators of bacterioplankton. This mortality and the release of cell lysis products into the environment can strongly influence microbial food web processes and biogeochemical cycles. Phages can also affect host diversity, e.g., by 'killing the winner' and keeping in check competitively dominant species or populations. Moreover, they mediate gene transfer between prokaryotes, but this remains largely unknown in the environment. Genomics or proteomics are providing us now with powerful tools in phage ecology, but final testing will have to be performed in the environment.

Ecology of prokaryotic viruses

What happens to terrestrial organic matter in the ocean

Dissolved organic matter (DOM) is the largest reservoir of reduced carbon in the oceans. The nature of DOM is poorly understood, in part, because it has been difficult to isolate sufficient amounts of representative material for analysis. Tangential-flow ultrafiltration was shown to recover milligram amounts of >1000 daltons of DOM from seawater collected at three depths in the North Pacific Ocean. These isolates represented 22 to 33 percent of the total DOM and included essentially all colloidal material. The elemental, carbohydrate, and carbon-type (by 13C nuclear magnetic resonance) compositions of the isolates indicated that the relative abundance of polysaccharides was high (∼50 percent) in surface water and decreased to ∼25 percent in deeper samples. Polysaccharides thus appear to be more abundant and reactive components of seawater DOM than has been recognized.

https://science.sciencemag.org/content/sci/255/5051/1561.full.pdf

Bulk chemical characteristics of dissolved organic matter in the ocean

Carbohydrate concentrations in depth profiles from the Atlantic and Pacific Oceans, the Gulf of Mexico, and the Gerlache Strait (Antarctica) were determined by MBTH analysis without hydrolysis and after hydrolysis with dilute HCI and concentrated H2SO4. Total carbohydrate (TCHO) concentrations in surface waters varied from 7 to 33 µM C and accounted for 21 ± 7% of the dissolved organic carbon (DOC) measured by high-temperature combustion. Polysaccharides (PCHO) were the dominant form of carbohydrate in waters above oxygen minima whereas monosaccharides were dominant in the deep ocean. PCHO comprised 71 ± 18% of TCHO and 16 ± 9% of the DOC above oxygen minima at all stations. Hydrolysis-resistant PCHO comprised 67 ± 30% of the total PCHO. Monosaccharide (MCHO) concentrations averaged 4.3 ± 1.9 µM C and varied little with depth at all stations. The large (5-fold) decrease in PCHO concentrations between surface waters and oxygen minima suggested that polysaccharides are an active component of the carbon cycle in the upper ocean.

https://aslopubs.onlinelibrary.wiley.com/doi/pdf/10.4319/lo.1994.39.4.0930

J. Dean Pakulski

Papers

Bulk chemical characteristics of dissolved organic matter in the ocean

Abundance and distribution of carbohydrates in the ocean

An improved method for the hydrolysis and MBTH analysis of dissolved and particulate carbohydrates in seawater