The effect of urbanisation on Laajalahti Bay, Helsinki City, as reflected by sediment geochemistry

Vaalgamaa, Sanna

doi:10.1016/j.marpolbul.2003.10.008

Cited by 59 publications

(42 citation statements)

References 38 publications

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“…The long-term effects of eutrophi cation on sediment organic content is not well known, but recent investigations in estuaries suggest dramatically elevated levels (e.g. 2−3 times the background level) following decades of eutrophication (Zimmerman & Canuel 2002, Vaalgamaa 2004.…”

Section: Introductionmentioning

confidence: 99%

Recovery of organic-enriched sediments through microbial degradation: implications for eutrophic estuaries

Valdemarsen¹,

Quintana²,

Kristensen³

et al. 2014

Mar. Ecol. Prog. Ser.

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Sediments in eutrophic estuarine ecosystems may become heavily enriched with organic carbon (OC). This OC is primarily of low reactivity and, therefore, has moderate effects on sediment biogeochemical cycling. Nonetheless, OC levels of >1% reduce sediment stability and cause frequent resuspensions and high water turbidity, which affect the recovery of ecosystem functioning. Significant reduction of sediment OC content to <1% is, therefore, needed before ecosystems can fully recover. It was investigated whether organic-rich sediments with 2.5 to 4.4% OC (180-310 mol m -2 ) from the eutrophic Odense Fjord (Denmark) can recover by microbial degradation. Defaunated sediment cores from various habitats were subjected to long-term (~2 yr) degradation experiments. Total OC content was measured initially and OC degradation was measured regularly from CO 2 effluxes and closed anoxic sediment incubations. OC degradation was high initially, but faded exponentially at all stations before stabilizing at 6 to 15 mmol OC m ) constituted a higher proportion (4−58% of total OC in organic-rich sediments). Furthermore, 43 to 95% of sediment OC was non-degradable. Our results suggest that partial recovery (5−57% reduction of initial OC) may occur within 23 to 50 yr. However, complete recovery of organic-rich sediments to <1% OC seems unlikely due to large pools of non-reactive OC. Eutrophication, therefore, leads to irreversible OC accumulation in sediments, which prolongs the recovery time for estuarine ecosystems after reductions in nutrient loading.

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Section: Introductionmentioning

confidence: 99%

Recovery of organic-enriched sediments through microbial degradation: implications for eutrophic estuaries

Valdemarsen¹,

Quintana²,

Kristensen³

et al. 2014

Mar. Ecol. Prog. Ser.

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“…The process of urbanization and industrialization is accompanied by increased automobile and industrial emissions of heavy metals to surrounding water bodies (Arnason and Fletcher, 2003;Vaalgamaa, 2004). Except industrial emission, most heavy metals have significant traffic related sources (Callender and vanMetre, 1997;Gardner and Carey, 2004;Ona et al, 2006).…”

Section: Introductionmentioning

confidence: 99%

Fraction distribution and risk assessment of heavy metals in sediments of Moshui Lake

Liu¹,

Li²,

Yin³

et al. 2008

Journal of Environmental Sciences

127

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To examine the status and risk of heavy metal pollution in urban lakes, in China, the distribution of several heavy metals (e.g., Cr, Cu, Ni, Pb, Zn) in the sediment of Moshui Lake, Hangyang District, Wuhan City, was characterized. The process of rapid urbanization and industrialization of the district was also studied to find out its relationship with the metal accumulation profile in the sediment. It was found that the total concentration of heavy metals in the sediment was higher than the severe effect level (SEL), at all sampling sites, except those in the riparian zone. The Cr and Cu maximum concentrations were 1,780 and 1,250 mg/kg, approximately 16 and 11 times as much as the SEL values, and they appeared as deep as 32 cm in one sample. The carbonate and exchangeable fractions of Zn were more than 50% of the total Zn content, resulting in very high risk according to the Risk Assessment Code (RAC). For Cu and Ni, a medium RAC value was found for carbonate and exchangeable fractions of 11%-20%. As sensitive indicators of contaminants in aquatic systems, heavy metals in the sediment reflect the outcome of regional urbanization, industrialization, and environmental management. With rapid urbanization, sedimentary Pb and Zn concentrations increased. The experimental results showed that high sedimentary heavy metal concentrations had resulted from rapid urbanization and industrialization, which would absolutely lead to substantial aquatic environmental decline in urban lakes.

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“…A geochemical indicator of phosphorus inputs to sediments remains elusive, despite the importance of understanding historical changes in the trophic status of aquatic ecosystems (Anderson and Rippey 1994;Engstrom and Wright 1985;Vaalgamaa 2004). Phosphorus in lake and coastal sediments changes relatively rapidly on paleoecological timescales, so total phosphorus is not generally considered to be a reliable indicator of the phosphorus status of a particular site at the time the sediment was deposited.…”

Section: Introductionmentioning

confidence: 99%

Phytate as a novel phosphorus-specific paleo-indicator in aquatic sediments

Turner

Weckström

2008

J Paleolimnol

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A reliable geochemical paleo-indicator for phosphorus remains elusive, despite the importance of understanding historical changes in the nutrient status of aquatic ecosystems. We assessed the potential of phytate (salts of mvo-inositol hexakisphosphate) as a novel phosphorus-specific paleoindicator by measuring its concentrations in dated sediments from an embayment in Helsinki, Finland, with a known 200-year history of trophic changes. Phytate was extracted in a solution containing sodium hydroxide and EDTA and detected by solution : P NMR spectroscopy with spectral deconvolution. Concentrations varied markedly with sediment depth and paralleled previously determined changes in diatom assemblages and geochemical indicators linked to trophic status. In contrast, total sediment phosphorus did not reflect phosphorus inputs to the embayment, presumably due to the mobilization of inorganic phosphate under anoxic conditions during

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The effect of urbanisation on Laajalahti Bay, Helsinki City, as reflected by sediment geochemistry

Cited by 59 publications

References 38 publications

Recovery of organic-enriched sediments through microbial degradation: implications for eutrophic estuaries

Recovery of organic-enriched sediments through microbial degradation: implications for eutrophic estuaries

Fraction distribution and risk assessment of heavy metals in sediments of Moshui Lake

Phytate as a novel phosphorus-specific paleo-indicator in aquatic sediments

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