Research Interests (Global Research Projects: 1, 2)

I am interested in early diagenetic reactions and elemental cycling involving the decomposition of organic matter, dissolution of inorganic biogenic debris, and the mobilization -reprecipitation of metals sensitive to oxidation-reduction. These reactions are most intense and rapid in the upper meter, and especially in the upper few centimeters, of marine sediment. It is in this upper zone where most benthic organisms live and interact with sediments and where exchange of material between sediment and overlying water is largely determined. Knowledge of early diagenetic processes occurring in this zone is, therefore, essential for understanding elemental cycling in sediments and overlying water, certain ecological interactions and adaptations of marine organisms, and the long-term recording of historical information in marine deposits, for example, fossil preservation.

My students and I are currently studying diagenetic processes, mineral authigenesis, and exchange rates of dissolved material across the sediment-water interface in a variety of coastal and deep-sea marine areas, including Long Island Sound, French Guiana (Amazon – Guianas mobile mudbelt), and Papua New Guinea. One major part of our research involves the development and application of 2-dimensional optical sensors for examination of biogeochemical heterogeneity and dynamics in the complex bioturbated zone.  For example, we have recently developed pH and pCO2 sensors which allow unprecedented resolution of biogeochemical reactions and solute transport patterns associated with biogenic structures.  A second major emphasis of our research is on large scale diagenetic patterns related to physically energetic sedimentary facies (mobile mud belts) and authigenic mineral formation, particularly Fe-rich clays (reverse weathering) and Fe-carbonates, in tropical deltaic systems.  These deltaic deposits contrast dramatically with bioturbated sediments and are dominated by physical mobilization of massive quantities of sedimentary debris. They are of extraordinary importance to elemental cycling and organic matter remineralization or storage globally. 

We have collaborative projects with other SoMAS and SUNY faculty as well as with colleagues at other institutions, including Josephine Aller, J. Kirk Cochran, Cindy Lee, John Mak, Qingzhi Zhu, and Richard Reeder (Geosciences), Neal Blair (NCSU); Gregg Brunskill (AIMS, Townsville, AU), Frédéric Baltzer (Univ. Paris), Yanzhen Fan (OSU), Franck Gilbert (Univ. Marseilles), Stefan Hulth (Göteborg Univ.), Charles Nittrouer (Univ. Washington), and Donald Rhoads (Woods Hole). Several of our ongoing research projects are listed here:

1. Development and use of planar optode sensors for in situ (SPI hyperspectral camera system – Chem-SPI – collaboration with D.C. Rhoads) and 2-D laboratory microcosm measurement of solute, solid, and microbial enzyme activity distributions.
2. Organic matter remineralization, suboxic reactions, and rates and kinetics of authigenic mineral dissolution-precipitation (particularly Fe-rich clays (reverse weathering reactions), carbonates, sulfur, biogenic silica) in tropical deltaic mobile mud facies and their impact on global biogeochemical cycles.
3. Animal-sediment interactions, particularly biogeochemical, of macrobenthos living in soft-bottom regions of the sea floor.
4. Studies of diffusion coefficients and exoenzyme activity in biogenic mucoid secretions.
5. Effects of macrobenthic organisms on microbial metabolic activity and on the rate and distribution of biogenic and abiogenic reactions in the bioturbated zone of sediments.

Selected Recent Publications

Aller, R.C. and N.E. Blair, 2006. Carbon remineralization in the Amazon - Guianas mobile mudbelt: a sedimentary incinerator. Cont. Shelf Res. 26, 2241-2259.

Madrid, V. M, R.C. Aller, J.Y. Aller, and A. Y. Chistoserdov. 2006, Evidence of the activity of dissimilatory sulfate-reducing prokaryotes in nonsulfidogenic tropical mobile muds. FEMS Microbiol Ecol. 57, 169-181.

Zhu, Q., R.C. Aller, and Y. Fan, 2006. Two-dimensional pH distributions and dynamics in bioturbated marine sediments. Geochim. Cosmochim. Acta . 70, 4933-4949.

Zhu, Q., R.C. Aller, and, Y. Fan, 2006. A new ratiometric, planar fluorosensor for measuring high resolution, two-dimensional pCO₂ distributions in marine sediments. Marine Chemistry 101, 40-53

Zhu, Q., R.C. Aller, and Y. Fan, 2005. High-performance planar pH fluorosensor for two-dimensional pH measurements in marine sediment and water. Environ. Sci. Technol. 39, 8906-8911.

Hannides, A. K., S.M. Dunn, and R.C. Aller, 2005. Diffusion of organic and inorganic solutes through macrofaunal mucus secretions and tube linings in marine sediments.  J. Mar. Res. 63, 957-981.

Aller, R.C., 2004. Conceptual models of early diagenetic processes: the muddy seafloor as an unsteady, batch reactor. J. Mar. Res.  62, 815-835.

Aller, R.C., C. Heilbrun, C. Panzeca, Z.-B. Zhu, and F. Baltzer, 2004. Coupling  between sedimentary dynamics, early diagenetic processes, and biogeochemical cycling in the Amazon-Guianas mobile mud belt: coastal French Guiana. Marine Geology, 208, 331-360.

Michalopoulos, P. and R.C. Aller, 2004. Early diagenesis of biogenic silica in the Amazon Delta:  alteration, authigenic clay formation, and storage.  Geochim. Cosmochim. Acta  68, 1061-1085.

Aller, R.C., A. Hannides, C. Heilbrun, and C. Panzeca. 2004. Coupling of early diagenetic processes and sedimentary dynamics in tropical shelf environments:  The Gulf of Papua deltaic complex.  Cont. Shelf Res. 24, 2455-2486.

Aller, J.Y. and R.C. Aller, 2004.Physical Disturbance creates bacterial dominance of benthic biological communities in tropical deltaic environments of the Gulf of Papua.  Continental Shelf Research, 24, 2395-2416

Ingalls, A. E., R.C. Aller, C. Lee, S. Wakeham, 2004. Organic matter diagenesis in calcium carbonate sediments. Geochim. Cosmochim. Acta. 68,  4363-4379.

D'Andrea, A., G. Lopez, and R.C. Aller, 2004. Rapid physical and biological particle mixing on an intertidal sandflat. J. Mar. Res., 62,67-92.

Aller, R.C. and N. E. Blair,  2004. Early diagenetic remineralization of sedimentary organic C in the Gulf of Papua deltaic complex (Papua New Guinea): net loss of terrestrial C and diagenetic fractionation of C isotopes.  Geochim. Cosmochim. Acta. 68, 1815-1825.

Blair, N.E., E.L. Leithold, and R.C.Aller, 2004. From bedrock to burial: the evolution of particulate organic carbon acrosscoupled watershed-continental margin systems.  Mar. Chem.  92, 141-156.

McKee, B. A., R.C. Aller, M. A. Allison, T. A. Bianchi, and G. C. Kineke,  2004. Transport and transformation of dissolved and particulate materials on continental margins influenced by major rivers: benthic boundary layer and seabed processes.  Cont. Shelf Res. 24(7-8),  899-926.

Gilbert, F., R.C. Aller, and S. Hulth, 2003. The influence of macrofaunal burrow spacing and diffusive scaling on sedimentary nitrification and denitrification: An experimental and model approach.  J. Mar. Res. 61, 101-125.

Hulth, S., R.C. Aller, P. Engström, and E. Selander, 2002. A pH plate fluorosensor (optode) for early diagenetic studies of marine sediments.  Limnol. Oceanogr. 47, 212-220.

Aller, R.C., 2001, Transport and reactions in the bioirrigated zone. In: The Benthic Boundary Layer: Transport processes and biogeochemistry. (B. P. Boudreau and B.B. Jorgensen, eds.). Oxford Press, Oxford. 269-301.

Michalopoulos, P., R. C. Aller, and R. Reeder, 2000. Conversion of diatoms to clay minerals during early diagenesis in tropical, continental shelf muds. Geology 28, 1095-1098.

Hulth, S., R.C. Aller, and F. Gilbert, 1999. Coupled anoxic nitrification/manganese reduction in marine sediments. Geochim. Cosmochim. Acta. 63, 49 – 66.

Green, M.A. and R.C. Aller, 1998. Seasonal patterns of carbonate diagenesis in nearshore terrigenous muds: relation to spring phytoplankton bloom and temperature. J. Mar. Res. 56, 1097-1123.

Aller, R.C., 1998. Mobile deltaic and continental shelf muds as fluidized bed reactors. Marine Chem. 61, 143-155.

Aller, R.C. and J.Y. Aller, 1998. The effect of biogenic irrigation intensity and solute exchange on diagenetic reaction rates in marine sediments. J. Mar. Res., 56, 905-936

Aller, R.C., N.E. Blair, Q, Xia and P.D. Rude. 1996. Remineralization rates, recycling and storage of carbon in Amazon shelf sediments. Cont. Shelf Res. 16:753-786;.

Michalopoulos, P. and R.C. Aller. 1995. Rapid clay mineral formation in Amazon delta sediments: reverse weathering and oceanic elemental cycles. Science 270:614-617.

Aller, R.C. 1994. Bioturbation and remineralization of sedimentary organic matter: effects of redox oscillation. Chem. Geol., 114:331-345:.

Sun,M.-Y., R.C. Aller and C. Lee. 1994. Spatial and temporal distributions of sedimentary chloropigments as indicators of benthic processes in Long Island Sound. Journal of Marine Research, 52:148-176;

Aller, R.C. 1994. The sedimentary Mn cycle in Long Island Sound: its role as intermediate oxidant and the influence of bioturbation, O₂, and Corg flux on diagenetic reaction balances. Journal of Marine Research, 52:259-295.

Aller, R.C. 1988. Benthic fauna and biogeochemical processes in marine sediments. In: Blackburn, T.H.; Sorenson, J., eds. Nitrogen cycling in coastal marine environments; New York: John Wiley and Sons; pp. 301-338.