Autor: |
Schnedl SM; Department of Palaeontology, University of Vienna, Austria., Haselmair A; Department of Palaeontology, University of Vienna, Austria., Gallmetzer I; Department of Palaeontology, University of Vienna, Austria., Mautner AK; Department of Palaeontology, University of Vienna, Austria., Tomašových A; Earth Science Institute, Slovak Academy of Sciences, Slovak Republic., Zuschin M; Department of Palaeontology, University of Vienna, Austria. |
Jazyk: |
angličtina |
Zdroj: |
The Holocene [Holocene] 2018 Nov; Vol. 28 (11), pp. 1801-1817. Date of Electronic Publication: 2018 Aug 02. |
DOI: |
10.1177/0959683618788651 |
Abstrakt: |
The effects of and the interplay between natural and anthropogenic influences on the composition of benthic communities over long time spans are poorly understood. Based on a 160-cm-long sediment core collected at 44 m water depth in the NE Adriatic Sea (Brijuni Islands, Croatia), we document changes in molluscan communities since the Holocene transgression ~11,000 years ago and assess how they were shaped by environmental changes. We find that (1) a transgressive lag deposit with a mixture of terrestrial and marine species contains abundant seagrass-associated gastropods and epifaunal suspension-feeding bivalves, (2) the maximum-flooding phase captures the establishment of epifaunal bivalve-dominated biostromes in the photic zone, and (3) the highstand phase is characterized by increasing infaunal suspension feeders and declining seagrass-dwellers in bryozoan-molluscan muddy sands. Changes in the community composition between the transgressive and the highstand phase can be explained by rising sea level, reduced light penetration, and increase in turbidity, as documented by the gradual up-core shift from coarse molluscan skeletal gravel with seagrass-associated molluscs to bryozoan sandy muds. In the uppermost 20 cm (median age <200 years), however, epifaunal and grazing species decline and deposit-feeding and chemosymbiotic species increase in abundance. These changes concur with rising concentrations of nitrogen and organic pollutants due to the impact of eutrophication, pollution, and trawling in the 20th century. The late highstand benthic assemblages with abundant bryozoans, high molluscan diversity, and abundance of soft-bottom epi- and infaunal filter feeders and herbivores represent the circalittoral baseline community largely unaffected by anthropogenic impacts. |
Databáze: |
MEDLINE |
Externí odkaz: |
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