Data compilation of respiration, feeding, and growth rates of marine pelagic organisms

The metabolic rate of organisms may either be viewed as a basic property from which other vital rates and many ecological patterns emerge and that follows a universal allometric mass scaling law; or it may be considered a property of the organism that emerges as a result of the organism's adaptation to the environment, with consequently less universal mass scaling properties. Data on body mass, maximum ingestion and clearance rates, respiration rates and maximum growth rates of animals living in the ocean epipelagic were compiled from the literature, mainly from original papers but also from previous compilations by other authors. Data were read from tables or digitized from graphs. Only measurements made on individuals of know size, or groups of individuals of similar and known size were included. We show that clearance and respiration rates have life-form-dependent allometries that have similar scaling but different elevations, such that the mass-specific rates converge on a rather narrow size-independent range. In contrast, ingestion and growth rates follow a near-universal taxa-independent ~3/4 mass scaling power law. We argue that the declining mass-specific clearance rates with size within taxa is related to the inherent decrease in feeding efficiency of any particular feeding mode. The transitions between feeding mode and simultaneous transitions in clearance and respiration rates may then represent adaptations to the food environment and be the result of the optimization of tradeoffs that allow sufficient feeding and growth rates to balance mortality.

Properties, sedimentation and accumulation rates, and chemical composition of bottom sediments from the Deryugin Basin, Sea of Okhotsk

Results of a study of contents and accumulation rates of Fe, Mn, and some trace elements in Upper Quaternary sediments of the Deryugin Basin are presented. Maps of average contents and accumulation rates of excessive Fe, Mn, Zn, Ba, Ni, Pb, Cu, and Mo in sediments of the first oxygen isotope stage (OIS) have been plotted. Anomalous contents and accumulation rates are confined to peripheral zones of the Deryugin sedimentary basin and large fracture zones. Different mechanisms of influence of fluid-dynamic processes on rate of hydrogenic and biogenic accumulation of ore elements are assumed.

Grain size analysis and sedimentation rates of ODP Hole 175-1085A off the Namibian coast

Sediments from the ODP Site 1085A were studied to investigate the impacts of global cooling in the Middle and Late Miocene on the climate in Southwestern Africa. The size composition of the sediment was analysed emphasising the silt fraction. A comparison with the modern grain size distribution and suitable transport processes made it possible to assign specific transport processes to the grain size composition. Three processes are considered for transport of terrigeneous silt: while there was no evidence found for (1) transport by ocean currents, the analyses showed signals of (2) wind transport indicating dry conditions associated with a cool climate and (3) fluvial transport that points to humid and warm conditions. Three climatic phases were defined. The first phase from 13.8 to 11.8 Myr reveals a stable humid climate in Southwest Africa independent of the Antarctic glaciations. During the second phase from 11.8 to 10.4 Myr the regional climate cooled considerably but was not drier. Additionally, the climate during this phase reacted to the Antarctic glaciations. This cooling-trend continued during phase 3 from 10.4 to 9.0 Myr with a significant increase in dust input, pointing to overall drier conditions. However, fluvial transport still remained as the main source.

Concentrations and accumulation rates of platinum-group elements and rhenium in Pacific and Atlantic sediments, DSDP and ODP data

The nature of Re-platinum-group element (PGE; Pt, Pd, Ir, Os, Ru) transport in the marine environment was investigated by means of marine sediments at and across the Cretaceous-Tertiary boundary (KTB) at two hemipelagic sites in Europe and two pelagic sites in the North and South Pacific. A traverse across the KTB in the South Pacific pelagic clay core found elevated levels of Re, Pt, Ir, Os, and Ru, each of which is approximately symmetrically distributed over a distance of ~1.8 m across the KTB. The Re-PGE abundance patterns are fractionated from chondritic relative abundances: Ru, Pt, Pd, and Re contents are slightly subchondritic relative to Ir, and Os is depleted by ~95% relative to chondritic Ir proportions. A similar depletion in Os (~90%) was found in a sample of the pelagic KTB in the North Pacific, but it is enriched in Ru, Pt, Pd, and Re relative to Ir. The two hemipelagic KTB clays have near-chondritic abundance patterns. The ~1.8-m-wide Re-PGE peak in the pelagic South Pacific section cannot be reconciled with the fallout of a single impactor, indicating that postdepositional redistribution has occurred. The elemental profiles appear to fit diffusion profiles, although bioturbation could have also played a role. If diffusion had occurred over ~65 Ma, the effective diffusivities are ~10**?13 cm**2/s, much smaller than that of soluble cations in pore waters (~10**?6 cm**2/s). The coupling of Re and the PGEs during redistribution indicates that postdepositional processes did not significantly fractionate their relative abundances. If redistribution was caused by diffusion, then the effective diffusivities are the same. Fractionation of Os from Ir during the KTB interval must therefore have occurred during aqueous transport in the marine environment. Distinctly subchondritic Os/Ir ratios throughout the Cenozoic in the South Pacific core further suggest that fractionation of Os from Ir in the marine environment is a general process throughout geologic time because most of the inputs of Os and Ir into the ocean have Os/Ir ratios >/=1. Mass balance calculations show that Os and Re burial fluxes in pelagic sediments account for only a small fraction of the riverine Os (<10%) and Re (<0.1%) inputs into the oceans. In contrast, burial of Ir in pelagic sediments is similar to the riverine Ir input, indicating that pelagic sediments are a much larger repository for Ir than for Os and Re. If all of the missing Os and Re is assumed to reside in anoxic sediments in oceanic margins, the calculated burial fluxes in anoxic sediments are similar to observed burial fluxes. However, putting all of the missing Os and Re into estuarine sediments would require high concentrations to balance the riverine input and would also fail to explain the depletion of Os at pelagic KTB sites, where at most ~25% of the K-T impactor's Os could have passed through estuaries. If Os is preferentially sequestered in anoxic marine environments, it follows that the Os/Ir ratio of pelagic sediments should be sensitive to changes in the rates of anoxic sediment deposition. There is thus a clear fractionation of Os and Re from Ir in precipitation out of sea water in pelagic sections. Accordingly, it is inferred here that Re and Os are removed from sea water in anoxic marine depositional regimes.

Geochemistry and accumulation rates of the early Paleogene in the Weddel Sea, Maud Rise and Kerguelen Plateau

Marine biological productivity has been invoked as a possible climate driver during the early Paleogene through its potential influence on atmospheric carbon dioxide concentrations. However, the relationship of export productivity (the flux of organic carbon (C) from the surface ocean to the deep ocean) to organic C burial flux (the flux of organic C from the deep ocean that is buried in marine sediments) is not well understood. We examine the various components involved with atmosphere-to-ocean C transfer by reconstructing early Paleogene carbonate and silica production (using carbonate and silica mass accumulation rates (MARs)); export productivity (using biogenic barium (bio-Ba) MARs); organic C burial flux (using reactive phosphorus (P) MARs); redox conditions (using uranium and manganese contents); and the fraction of organic C buried relative to export productivity (using reactive P to bio-Ba ratios). Our investigations concentrate on Paleocene/Eocene sections of Sites 689/690 from Maud Rise and Site 738 from Kerguelen Plateau. In both regions, export productivity, organic C burial flux, and the fraction of organic C buried relative to export productivity decreased from the Paleocene/early Eocene to the middle Eocene. A shift is indicated from an early Paleogene two-gyre circulation in which nutrients were not efficiently recycled to the surface via upwelling in these regions, to a circulation more like the present day with efficient recycling of nutrients to the surface ocean. Export productivity was enhanced for Kerguelen Plateau relative to Maud Rise throughout the early Paleogene, possibly due to internal waves generated by the plateau regardless of gyre circulation.

Beryllium-10 and aluminium-26 concentration and production rates in glacial deposits from the Quartermain Mountains

Many glacial deposits in the Quartermain Mountains, Antarctica present two apparent contradictions regarding the degradation of unconsolidated deposits. The glacial deposits are up to millions of years old, yet they have maintained their meter-scale morphology despite the fact that bedrock and regolith erosion rates in the Quartermain Mountains have been measured at 0.1-4.0 m/Ma. Additionally, ground ice persists in some Miocene-aged soils in the Quartermain Mountains even though modeled and measured sublimation rates of ice in Antarctic soils suggest that without any recharge mechanisms ground ice should sublimate in the upper few meters of soil on the order of 10**3 to 10**5 years. This paper presents results from using the concentration of cosmogenic nuclides beryllium-10 (10Be) and aluminum-26 (26Al) in bulk sediment samples from depth profiles of three glacial deposits in the Quartermain Mountains. The measured nuclide concentrations are lower than expected for the known ages of the deposits, erosion alone does not always explain these concentrations, and deflation of the tills by the sublimation of ice coupled with erosion of the overlying till can explain some of the nuclide concentration profiles. The degradation rates that best match the data range 0.7-12 m/Ma for sublimation of ice with initial debris concentrations ranging 12-45% and erosion of the overlying till at rates of 0.4-1.2 m/Ma. Overturning of the tills by cryoturbation, vertical mixing, or soil creep is not indicated by the cosmogenic nuclide profiles, and degradation appears to be limited to within a few centimeters of the surface. Erosion of these tills without vertical mixing may partially explain how some glacial deposits in the Quartermain Mountains maintain their morphology and contain ground ice close to the surface for millions of years.

Ages and sedimentation rates of bottom sediments from the south arid zone of the Pacific Ocean

Radiocarbon datings are used to calculate mean sedimentation rates of metalliferous sediments in the southern arid zone of the Pacific Ocean adjoining the axis of the East Pacific rise (20°S). Owing to low sedimentation rates and intense mixing, only averaged figures could be obtained for ages less than 16 ky. Sedimentation rate varies from 0.3 to about 1 cm/1000 years in the surface layer and is several times higher in the time interval from 20 ky to 45 ky ago. Formulas for calculating mean sedimentation rates with allowance for benthic mixing are presented.

(Table 1) Thickness of the Holocene layer and sedimentation rates in the Atlantic Ocean

On the basis of planktonic foraminifera study, thickness of Holocene sediments has been ascertained in 60 sediment cores from various regions of the Atlantic Ocean. Ratios of species reflect warming of the upper water layer at the Pleistocene-Holocene boundary over the entire ocean. The Holocene boundary can be determined not only from microfaunal data, but also from lithologic ones including textural and structural features. Increase in CaCO3 contents in Holocene sediments as compared to Pleistocene is from 5-7% to 60-70% in different parts of the ocean.