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Water column
About: Water column is a research topic. Over the lifetime, 13706 publications have been published within this topic receiving 496626 citations.
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TL;DR: The modes of sediment reworking and structure building, irrigation behaviour, and burrowing depths were factors sufficient to assign the 3 dominant species of shallow water habitats into different functional groups.
Abstract: Benthic invertebrates play a key role in the physical, chemical, and biological properties of the marine water-sediment interface. The influences of invertebrates on biogeochemical processes have mainly been attributed to their sediment reworking and bioirrigation activities. The aim of this study was to compare the influences of bioturbation activities by 3 dominant species of shallow water habitats (Cerastoderma edule, Corophium volutator, and Nereis diversicolor) on microbial communi- ties and biogeochemical processes in sediment cores. C. edule acted as a biodiffuser, mixing surface particles in the top 2 cm of the sediment. Despite this mixing activity, this species had little effect on O2 consumption, water exchange between the water column and the sediment, microbial character- istics, and release of nutrients from the sediment. In contrast, C. volutator and N. diversicolor produced burrows in the sediment that allowed transport of surface particles into biogenic structures. These 2 species doubled the solute exchange between the water column and the sediment. Such modifications of sediment structure and solute transport increased the O2 consumption and the release of nutrients from the sediment. Both C. volutator and N. diversicolor stimulated the microbial communities as indicated by higher percentages of active bacteria. Reduction of the numbers of sulphate reducing bacteria was observed when the 3 invertebrates were present and could be attrib- uted to the penetration of O2 due to animal activities. N. diversicolor had a greater influence than C. volutator on pore water chemistry, ammonium release, and active bacteria. As N. diversicolor burrowed deeper in the sediment than C. volutator, it irrigated a greater volume of sediment. The modes of sediment reworking and structure building, irrigation behaviour, and burrowing depths were factors sufficient to assign the 3 species into different functional groups.
239 citations
TL;DR: Sediment trap material collected at five depths from two locations in Lake Michigan has been studied to determine the sources of particulate organic matter and the early diagenetic changes which occur during sinking of particles as discussed by the authors.
238 citations
TL;DR: In this paper, the authors show that wind resuspension and bioturbation, combined with high pH or low Fe/P ratio that maintains high P solubility, periodic anoxia and reducing conditions promoted by metalimnia may serve as barriers to phosphorus transport into the trophogenic zone.
Abstract: Decreasing the algal biomass and increasing transparency in shallow, unstratified lakes is usually more difficult than for deep, stratified lakes. Eutrophic unstratified lakes (or shallow, stratified lakes susceptible to metalimnion erosion) have typically responded slowly to reduced external nutrient loading, usually because of longevity of internal loading. That is because sediment-released nutrients (especially phosphorus) readily enter the trophogenic zone of shallow lakes during the growing season and result in high lake concentrations. In stratified lakes, metalimnia may serve as barriers to phosphorus transport into the trophogenic zone. Although the whole water column in shallow lakes is usually aerobic, several mechanisms can combine to produce relatively high sediment phosphorus release rates in these lakes. These include: 1) wind resuspension and bioturbation, combined with high pH or low Fe/P ratio that maintains high P solubility, 2) periodic anoxia and reducing conditions promoted b...
238 citations
TL;DR: In this article, the authors used the Meade Peak Phosphatic Shale Member of the Phosphoria Formation, a phosphate deposit of Permian age in the northwest United States, to model accumulation rates of Cd, Cr, Cu, Mo, Ni, V, and Zn on the seafloor.
238 citations
TL;DR: It is likely to be unsafe to consume aquatic species harvested in Lake Taihu due to the high-concentrations of accumulated MCs, and the need for tracking MCs not only in the entire water column but also at the interface between water and sediment is emphasized.
236 citations