Skip to Main Content
GEOREF RECORD

Stratigraphic unmixing reveals repeated hypoxia events over the past 500 yr in the northern Adriatic Sea

Adam Tomasovych, Ivo Gallmetzer, Alexandra Haselmair, Darrell S. Kaufman, Jelena Vidovic and Martin Zuschin
Stratigraphic unmixing reveals repeated hypoxia events over the past 500 yr in the northern Adriatic Sea
Geology (Boulder) (April 2017) 45 (4): 363-366

Abstract

In the northern Adriatic Sea and in most semienclosed coastal regions worldwide, hypoxia induced by eutrophication in the late 20 (super th) century caused major die-offs of coastal marine organisms. However, ecosystem responses to hypoxia over longer centennial scales are unclear because the duration of direct observations is limited to a few decades and/or the temporal resolution of sedimentary archives is compromised by slow sedimentation and bioturbation. To assess whether perturbations of ecosystems by hypoxia recurred over centuries in the northern Adriatic Sea, we evaluate the timing and forcing of past hypoxia events based on the production history of the opportunistic, hypoxia-tolerant bivalve Corbula gibba, using (super 210) Pb data, radiocarbon dating, amino acid racemization, and distribution of foraminifers in sediment cores that capture the past 500 yr in the Gulf of Trieste. Unmixing the stratigraphic record on the basis of 311 shells of C gibba, we show that the reconstructed fluctuations in abundance do not correlate with abundances in the raw stratigraphic record. We find that production of C gibba has undergone major decadal-scale fluctuations since the 18 (super th) century, with outbreaks corresponding to density of more than 1000 individuals per square meter. These outbreaks represent long-term phenomena in the northern Adriatic ecosystem rather than novel states characteristic of the 20 (super th) century eutrophication. They positively correlate with centennial-scale fluctuations in sea-surface temperature, indicating that the hypoxia events were coupled with water-column stratification rather than with nutrient enrichment.


ISSN: 0091-7613
EISSN: 1943-2682
Coden: GLGYBA
Serial Title: Geology (Boulder)
Serial Volume: 45
Serial Issue: 4
Title: Stratigraphic unmixing reveals repeated hypoxia events over the past 500 yr in the northern Adriatic Sea
Affiliation: Slovak Academy of Sciences, Earth Science Institute, Bratislava, Slovakia
Pages: 363-366
Published: 201704
Text Language: English
Publisher: Geological Society of America (GSA), Boulder, CO, United States
References: 33
Accession Number: 2017-025963
Categories: Quaternary geology
Document Type: Serial
Bibliographic Level: Analytic
Annotation: GSA Data Repository item 2017104
Illustration Description: illus.
N45°28'60" - N45°49'00", E13°22'60" - E13°46'60"
Secondary Affiliation: University of Vienna, AUT, AustriaNorthern Arizona University, USA, United States
Country of Publication: United States
Secondary Affiliation: GeoRef, Copyright 2017, American Geosciences Institute. Reference includes data from GeoScienceWorld, Alexandria, VA, United States. Reference includes data supplied by the Geological Society of America, Boulder, CO, United States
Update Code: 201716
Close Modal
This Feature Is Available To Subscribers Only

Sign In or Create an Account

Close Modal
Close Modal