We examined the chemical composition and bioavailability of dissolved organic carbon (DOC) and nitrogen (DON) from two pristine and two polluted cedar bog wetlands across three seasons. Pristine and polluted wetlands differed in DOC and DON concentrations, chemical characteristics, and bioavailability. DOC and DON concentrations were higher in the polluted than in the pristine wetlands. In cont...

Macroalgae or macrophytes are a heterogeneous assemblage of macroscopic eukaryotes belonging to various evolutionary lineages, which live predominantly in aquatic habitats. They have undifferentiated vegetative bodies organized in pseudoparanchymatous and parenchymatous bodies. As with higher plants, marine macroalgae or seaweeds are photosynthetic species that, by harvesting sunlight energy, c...

Seawater from the northern Adriatic, with low phosphorus (0.03 WM) and nitrogen (1.0 WM NO3 and 1.0 WM NH4) concentration, was incubated for 12 days in 20-l polycarbonate carboys. The addition of a nutrient mixture (0.6 WM PO4, 5.1 WM NO3, 1.8 WM NH4, 10.6 WM SiO2) induced a strong diatom bloom, reaching 25 Wg l31 Chl a. Primary and bacterial production were stimulated by the initial enrichment...

Understanding interactions between permanently frozen soils and stream chemistry is important in predicting the effects of management, natural disturbance and changing permafrost distribution on stream ecosystems and nutrient budgets in subarctic watersheds. Chemical measurements of groundwater, soil water and stream water were made in two watersheds in the taiga of interior Alaska. One watersh...

Appropriate conditions have been achieve d for the accurate, rapid, and highly precise shipboard simultaneous determination of dissolved organic carbon and total dissolved nitrogen in seawater by high tem perature catalytic oxidation. A nitrogen-specific Antek 705D chemiluminescence detector and a CO 2-specific LiCor Li6252 IRGA have been coupled inseries with a Shimadzu TOC-5000 organic carbon...

[1] Physical and biogeochemical processes determining the distribution, transport, and fate of nutrients delivered by the Mississippi and Atchafalaya river basin (MARB) to the inner Louisiana continental shelf (LCS) were examined using a three-dimensional hydrodynamic model and observations of hydrography, nutrients, and organic carbon collected during 12 cruises. Two aspects of nutrient transp...

Urban grasslands not only provide a recreational venue for urban residents, but also sequester organic carbon in vegetation and soils through photosynthesis, and release carbon dioxide through respiration, which largely contribute to carbon storage and fluxes at regional and global scales. We investigated organic carbon and nitrogen pools in subtropical turfs and found that dissolved organic ca...

Access to bioavailable nitrogen often limits primary production in marine and freshwater ecosystems. Around 70% of nitrogen transported by rivers worldwide consists of dissolved organic nitrogen (DON), but its bioavailability has been poorly investigated. To assess the potential bacterial growth on DON, we developed a bioassay employing natural DON and bacterial inocula in medium manipulated to...