I've excerpted a few sentences from some references. To get the full picture, reading the article is the way to go.
John S Gray, "Animal-Sediment Relationships", Oceanogr. Mar. Biol. Ann. REv., 1974, 12, 223-261, Ed Harold Barnes. Old but still a basic reference.
From page 249, "In general, for each set [of sublittoral data points from the Irish Sea], the coarsest deposits have low diversity [of infauna], the medium grade deposits have the highest, whilst in mud, diversity falls." Epifauna is most diverse in the coarse substrates in this data. Also: "Mixed substrates the highest diversity."
For samples from the North Carolina coast, the results are quite similar, although this section doesn't use the term mud. Instead, he uses the phi scale. If anyone really cares, I can probably look up the scale and convert it to mm. "Mud" in terms of this paper is much finer than the substrates we use.
Donald C Rhoads, "Organism-Sediment Relationships on the Muddy Sea Floor", Oceanogr. Mar. Biol. Ann. Rev, 1974, 12, 263-300, Ed. Harold Barnes.
This paper is more about muddy bottoms than our sandy tanks, but some of the data are still useful, IMO.
For notes on diffusions vs bioturbation for moving compounds in the sand bed: "The relative lack of importance of molecular diffusion compared with biological transport may be seen by comparin the diffusion flux vector (J) for sulphate in the sublittoral muds of Long Island Sound of 4x10-4 g sulphur/cm2/yr (Rhoads, 1972) and the capacity of a population of a common deposit-feeding bivalve, Yoldia iimulata (sp?), in those same muds to transfer vertically 6 to 12 g sediment/cm2/r (Rhoads, 1963)." It continues "The rates of molecular diffusion flux are several orders of magnitude less than vertical transport by infauna benthos." Keep in mind that these quotes cover specific habitats, and the paper notes that these might not generalize to deep-sea muds. (page 276)
As an interesting note: "We have seen that intensive bioturbation or biodeposition results in faecal pellet production, giving a sea floor consisting mainly of faecal pellets, which are available to coprophagous benthos." (page 283)
Douglas G Capone et al, "Microbial nitrogen transformations in unconsolidated reef sediments", Marine Ecology Progress Series, vol. 80, 75-88, 1992.
From Table 4, p. 80, denitrification was "highest in medium and coarse-grained sediments from Bowl Reef incubated in anaerobic conditions." Denitrification did occur in those sediments when incubated with oxygen, though. The highest rate was about 1/36 that of the best anaerobic conditions, though. Some sediments showed higher denitrification under aerobic incubation.
Robert C Adler and Josephine Y Yingst, "Effects of the marine deposit-feeders Heteromastus filiformis (Polychaeta), Macoma balthica (Bivalvia), and Tellina texana (Bivalvia) on averaged sedimentary solute transport, reaction rates, and microbial distributions", Journal of Marine Research, 43, 615-645, 1985.
Starting on page 620: "...so that the total NH4+ production rate is ~26 uM/d at 29 +- 1.0 deg C. The net production rate of alkalinity is ~0.16 meq/liter pore water/day." From page 622: "Si(OH)4 fluxes were lowest in the control tank..." From Table 1, the flux was on the order of roughly 5mmoles/m2/day.
The abstract is a bit more specific: "Most of the NH4+... was apparently oxidized at the sediment water interface... and... results in a major zone of low pH and HCO3- consumption at a rate > 24 meq/m2/d. This should cause substantial dissolution of CaCO3, as shown in previous studies." Not bad, eh? Also, "A zone of elevated Si(OH)4 production is also associated with the redoxcline." Hmm, I thought somewhere there was reference to the source.
That's not too late, IME. Some phosphate tests on the sand might be good for the truly paranoid. I have to disagree here totally. My sand was pure white , I never had cyano . So why would I get algae on the LR and not the sand ?
