Long-Term and Seasonal Trends in Estuarine and Coastal Carbonate Systems

Show full item record



Permalink

http://hdl.handle.net/10138/298264

Citation

Carstensen , J , Chierici , M , Gustafsson , B G & Gustafsson , E 2018 , ' Long-Term and Seasonal Trends in Estuarine and Coastal Carbonate Systems ' , Global Biogeochemical Cycles , vol. 32 , no. 3 , pp. 497-513 . https://doi.org/10.1002/2017GB005781

Title: Long-Term and Seasonal Trends in Estuarine and Coastal Carbonate Systems
Author: Carstensen, Jacob; Chierici, Melissa; Gustafsson, Bo G.; Gustafsson, Erik
Contributor: University of Helsinki, Tvärminne Zoological Station
Date: 2018-03
Language: eng
Number of pages: 17
Belongs to series: Global Biogeochemical Cycles
ISSN: 0886-6236
URI: http://hdl.handle.net/10138/298264
Abstract: Coastal pH and total alkalinity are regulated by a diverse range of local processes superimposed on global trends of warming and ocean acidification, yet few studies have investigated the relative importance of different processes for coastal acidification. We describe long-term (1972-2016) and seasonal trends in the carbonate system of three Danish coastal systems demonstrating that hydrological modification, changes in nutrient inputs from land, and presence/absence of calcifiers can drastically alter carbonate chemistry. Total alkalinity was mainly governed by conservative mixing of freshwater (0.73-5.17mmolkg(-1)) with outer boundary concentrations (similar to 2-2.4mmolkg(-1)), modulated seasonally and spatially (similar to 0.1-0.2mmolkg(-1)) by calcifiers. Nitrate assimilation by primary production, denitrification, and sulfate reduction increased total alkalinity by almost 0.6mmolkg(-1) in the most eutrophic system during a period without calcifiers. Trends in pH ranged from -0.0088year(-1) to 0.021year(-1), the more extreme of these mainly driven by salinity changes in a sluice-controlled lagoon. Temperature increased 0.05 degrees Cyr(-1) across all three systems, which directly accounted for a pH decrease of 0.0008year(-1). Accounting for mixing, salinity, and temperature effects on dissociation and solubility constants, the resulting pH decline (0.0040year(-1)) was about twice the ocean trend, emphasizing the effect of nutrient management on primary production and coastal acidification. Coastal pCO(2) increased similar to 4 times more rapidly than ocean rates, enhancing CO2 emissions to the atmosphere. Indeed, coastal systems undergo more drastic changes than the ocean and coastal acidification trends are substantially enhanced from nutrient reductions to address coastal eutrophication.
Subject: acidification
eutrophication
global warming
alkalinity
estuarine mixing
OCEAN ACIDIFICATION
BALTIC SEA
BIOGEOCHEMICAL PROCESSES
DANISH ESTUARIES
TOTAL ALKALINITY
CHESAPEAKE BAY
EUTROPHICATION
SEAWATER
WATERS
PH
1172 Environmental sciences
Rights:


Files in this item

Total number of downloads: Loading...

Files Size Format View
Carstensen_et_a ... _Biogeochemical_Cycles.pdf 5.151Mb PDF View/Open

This item appears in the following Collection(s)

Show full item record