Recovery from multi‐millennial natural coastal hypoxia in the Stockholm Archipelago, Baltic Sea, terminated by modern human activity

Helmond, Niels A. G. M. van; Lougheed, Bryan C; Vollebregt, Annika; Peterse, Francien; Fontorbe, Guillaume; Conley, Daniel J.; Slomp, Caroline P.

doi:10.1002/lno.11575

Cited by 9 publications

(3 citation statements)

References 67 publications

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“…In the pre-industrial (<1750 calendar years common era (CE), based on the detailed age model of Jilbert and Slomp (2013), sedimentary Hg content did not exceed 40 ppb, whereas it reached a maximum well above 200 ppb around ~1980 CE. Core F80 seems to record a subtle increase in Hg and Hg/TOC from about 1100-1200 CE, suggesting that, for example, smallscale early industrial activity or deforestation around the Baltic Sea may have influenced Hg influx at our sites, as is also supported by the Pb record in the study by van Helmond et al (2020). The pre-industrial Holocene Hg and TOC contents in our cores are very similar to those obtained during earlier work in the Baltic Sea that focused mainly on the recent centuries and effects of modern anthropogenic Hg pollution (Leipe et al, 2013).…”

Section: Influence Of Transient Changes In Oxygenation: Baltic Sea So...supporting

confidence: 68%

Effects of redox variability and early diagenesis on marine sedimentary Hg records

Frieling

Mather

März

et al. 2022

Preprint

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Volcanism is a dominant natural source of mercury (Hg) to the atmosphere, biosphere, ocean and sediments. In recent years, sedimentary Hg contents have emerged as a tool to reconstruct volcanic activity, and particularly activity of (subaerially emplaced) large igneous provinces in geological deep time. More specifically, Hg has shown potential as a useful proxy to illuminate the previously elusive impact of such large-scale volcanism on marine and terrestrial paleo-environments. While Hg is now widely applied as volcanism tracer, non-volcanic factors controlling sedimentary Hg content are generally not well constrained. Part of this uncertainty stems from our inability to directly observe a natural unperturbed "steady-state" environment as a baseline, as the modern Hg cycle is heavily influenced by anthropogenic activity. Here we focus on the effects of ambient redox conditions in the water column and shallow sediments (early diagenesis), quantify their influence on the geological Hg record and thereby contribute to constraining their potential impact on the use of Hg as a proxy for deep-time volcanic activity. Constraining these factors is of critical importance for the application of Hg as such a proxy. Many periods in the geological past for which records have been generated, such as the Mesozoic Oceanic Anoxic Events, are marked by a variety of high-amplitude environmental perturbations, including widespread deoxygenation and deposition of organic-rich sediments. We estimate the impact of redox changes and early diagenesis on the geological Hg record using a suite of (sub)recent-Pleistocene and Upper Cretaceous sediments representing oxic to euxinic marine conditions. Our sample set includes a transect through an oxygen minimum zone and cores that record transient shifts in oxygenation state, as well as post-depositional effectsall unrelated to volcanism, to the best of our knowledge. We find substantial alterations to the Hg record and the total organic carbon and total sulfur content, which are typically assumed to be the most common carrier phases of Hg in marine sediments. Moreover, these biases can lead to signal alteration on a par with those interpreted to result from volcanic activity. Geochemical modifications are ubiquitous and their potential magnitude implies that the factors leading to biases in the geological record warrant careful consideration before interpretation. Factors of particular concern to proxy application are (1) the disproportionate loss of organic carbon and sulfur relative to Hg during oxidation that strongly modulates normalized Hg records, (2) the evasion of Hg in anoxic and mildly euxinic sediments and (3) sharp focusing of Hg during post-depositional oxidation of organic matter. We suggest that paired analyses of additional redox-sensitive trace elements such as molybdenum, and organic-matter characteristics, particularly the type of organic matter, could provide first-order constraints on the role that redox and diagenetic changes played in shaping the Hg record as part of ...

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Section: Influence Of Transient Changes In Oxygenation: Baltic Sea So...supporting

confidence: 68%

Effects of redox variability and early diagenesis on marine sedimentary Hg records

Frieling

Mather

März

et al. 2022

Preprint

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“…Water in the second largest archipelago of the Baltic Sea is brackish, with a salinity lower than 7 p.p.m. and a high input of freshwater [11]. Ice formation is not uncommon during winter.…”

Section: Isolation and Ecologymentioning

confidence: 99%

Shewanella septentrionalis sp. nov. and Shewanella holmiensis sp. nov., isolated from Baltic Sea water and sediments

Martín‐Rodríguez

Thorell

Joffré

et al. 2023

International Journal of Systematic and Evolutionary Microbiology

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Two bacterial strains, SP1W3T and SP1S2-7T, were isolated from samples of water and sediments collected in Vaxholm, a town located on the Stockholm archipelago in the Baltic Sea, in November 2021. The strains were identified as novel genomic species within the genus Shewanella , based upon comparative analysis of whole genome sequence data. Strain SP1W3T (genome size, 5.20 Mbp; G+C content, 46.0 mol%), isolated from water, was determined to be most closely related to S. hafniensis ATCC-BAA 1207T and S. baltica NCTC 10735T, with digital DNA–DNA hybridization (dDDH) values of 61.7% and 60.4 %, respectively. Strain SP1S2-7T (genome size, 4.26 Mbp; G+C content, 41.5 mol%), isolated from sediments, was observed to be most closely related to S. aestuarii JCM17801T, with a pairwise dDDH value of 33.8 %. Polyphasic analyses of physiological and phenotypic characteristics, in addition to genomic analyses, confirmed that each of these two strains represent distinct, novel species within the genus Shewanella , for which the names Shewanella septentrionalis sp. nov. (type strain SP1W3T=CCUG 76164T=CECT 30651T) and Shewanella holmiensis sp. nov. (type strain SP1S2-7T=CCUG 76165T=CECT 30652T) are proposed.

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“…Many coastal areas of the Baltic Sea show evidence for anthropogenic eutrophication (Conley et al, 2011) which often leads to enhanced carbon loading to sediments (Jokinen et al, 2018;Helmond et al, 2020). At Storfjärden, we observe a steady rise in OC phyt .…”

Section: Discussion Terrestrial Organic Matter Loading To the Sediments During The 20th Centurymentioning

confidence: 64%

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Recovery from multi‐millennial natural coastal hypoxia in the Stockholm Archipelago, Baltic Sea, terminated by modern human activity

Cited by 9 publications

References 67 publications

Effects of redox variability and early diagenesis on marine sedimentary Hg records

Effects of redox variability and early diagenesis on marine sedimentary Hg records

Shewanella septentrionalis sp. nov. and Shewanella holmiensis sp. nov., isolated from Baltic Sea water and sediments

DataSheet1.DOCX

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