Changing sedimentation in tidal flat sediments of the southern North Sea from the Holocene to the present: a geochemical approach

Dellwig, Olaf; Hinrichs, Joachim; Hild, Andreas; Brumsack, Hans‐Jürgen

doi:10.1016/s1385-1101(00)00051-4

Cited by 86 publications

(44 citation statements)

References 12 publications

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“…This ra tio also char ac ter izes changes in the source of the de tri tal heavy min eral con tent (Muhs et al, 2008). Dellwig et al (2000) found that Zr is a more sen si tive in di ca tor of heavy min er als than is Ti, be cause Ti is to a larger ex tent bound to clay min er als in ad di tion to the heavy mineral frac tion. Thus, an in crease in the Zr/Ti ra tio should in di cate a greater in flu ence of the heavy min er als com pared with clay.…”

Section: Factors and Element Ratiosmentioning

confidence: 86%

“…Pre sum ably, this ra tio re flects the pro por tion of the heavy miner als in the to tal amount of heavy or light min er als, ex cept for quartz. This pre sump tion is based on the fact that Ti has sig nif icant load ings on both F1all and F2all and Zr only on F2all; this find ing is sim i lar to that of Dellwig et al (2000). Fac tor F3all (S, As, TOC have the great est load ings) is prob a bly re lated to or ganic mat ter and sulphides.…”

Section: Factors and Element Ratiosmentioning

confidence: 94%

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Sedimentary environment changes during the Early-Middle Pleistocene transition as recorded by the Daumantai sections in Lithuania

Baltrūnas

Zinkutė

Katinas

et al. 2012

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Sed i men tary en vi ron ment changes dur ing the Early-Mid dleTwo sec tions (Daumantai-1 and Daumantai-3) in East Lith u a nia ex pose Early-Mid dle Pleis to cene lac us trine-al lu vial, de posits which lie on a thin Neo gene layer and on older De vo nian rocks. They are over lain by glacigenic de pos its. Geo chem i cal, palaeomagnetic, mag netic sus cep ti bil ity, plant macrofossil, and di a tom in ves ti ga tions were per formed to de ter mine the changes in the sed i men tary en vi ron ment. Clus ter anal y sis of the geo chem i cal vari ables (10 ma jor el e ments, 16 trace el ements, to tal or ganic and in or ganic car bon) re vealed the el e ment groups and fac tors. The low er most units are char ac ter ized by a ma jor in flu ence of lo cal ma te rial and sig nif i cant fluc tu a tions in heavy min eral con tent. These fluc tu a tions might re flect short-term cli mate changes. The tran si tional units have more ex pressed trends, es pe cially as re gards the trace el e ments and Zr/Ti. The up per most units are char ac ter ized by a slight in flu ence of lo cal ma te rial and small fluc tu a tions in trace el ements. The data ana lysed en able the sub di vi sion of the sec tion into units re lated to changes in sed i men tary en vi ron ment. The bound ary of the Bruhnes/Matuyama re ver sal in the Daumantai-1 and Dauma ntai-3 sec tions was de tected by palaeomagnetic stud ies and en ables the strati graphi cal cor re la tion of these de pos its.Key words: Early-Mid dle Pleis to cene, en vi ron men tal changes, geo chem is try, mag netic sus cep ti bil ity, plant macroremains, Lith u a nia.

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Section: Factors and Element Ratiosmentioning

confidence: 86%

Section: Factors and Element Ratiosmentioning

confidence: 94%

Sedimentary environment changes during the Early-Middle Pleistocene transition as recorded by the Daumantai sections in Lithuania

Baltrūnas

Zinkutė

Katinas

et al. 2012

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“…Furthermore, high SPM values also have been documented close to the dyke (Dellwig et al, 2000). A large proportion of re-suspended benthic microalgae is found in the phytoplankton at high SPM contents (Baillie & Welsh, 1980).…”

mentioning

confidence: 83%

“…This material therefore remains suspended in the water column and causes turbidity (Flemming & Nyandwi, 1994;Dellwig et al, 2000). Hence the sediment characteristics of each station in Table 2 may reflect a 'tidal' gradient, which remains relatively constant along the transect and, with exception of grain size, does not vary much during the annual cycle.…”

mentioning

confidence: 99%

Microphytobenthic dynamics in a Wadden Sea intertidal flat – Part II: Seasonal and spatial variability of non-diatom community components in relation to abiotic parameters

Scholz

Liebezeit

2012

European Journal of Phycology

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The microphytobenthos colonizing the intertidal flats forms an important component of the Wadden Sea. Ten sampling points along a 1-km transect were studied in a fringe area of the Soltho¨rn tidal flat, southern North Sea, in order to determine seasonal differences in the microphytobenthos. An accompanying paper deals with the major component of the flora, the diatoms; here we, focus on the minor taxonomic groups. From May 2008 to May 2009 surface sediments were collected during low tide. Variation of environmental factors as well as microphytobenthic density (abundance and chlorophyll a) were monitored. The area investigated was a mixed-sediment mudflat, with a gradient from coarse to fine. Highest biomass was obtained in summer 2008 with 215.9 AE 12.6 mg chlorophyll a m -2 . In late autumn the chlorophyll a concentration decreased continuously at all investigated stations. Lowest values were detected in December 2008. Species abundances varied considerably both along the transect and seasonally, depending on species-specific requirements as well as hydrodynamic conditions (tidal currents). Higher densities of benthic pro-and eukaryotic microalgae were observed in sites characterized by fine sediments. Apart from the diatoms, the most abundant microphytobenthic group was the cyanophytes. Coccoid cyanophytes, mainly Merismopedia sp., were most abundant during summer, with cell numbers up to 5.72 Â 10 6 cells cm À2, while diatoms dominated in winter, spring and autumn. Filamentous cyanophytes, particularly Microcoleus chthonoplastes, were most abundant during autumn, while coccoid chlorophytes (spring: Chlorococcum submarinum, Crucigenia tetrapedia, Tetraselmis suecica), euglenophytes (summer: Euglena obtusa), dinophytes (autumn: Amphidinium operculatum, A. herdmanii) and cryptophytes (autumn: Hillea marina, Hemiselmis virescens) contributed to the microphytobenthos during warmer seasons. The statistical analysis confirmed that the composition of the microphytobenthos was related to sediment features and to characteristics of particular seasons.

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“…In general, periods with enhanced near-bottom cur-rents become recorded in sediments through increased proportion of coarse grains (e.g., Hjulström, 1939). and thus it concentrates in the coarse fraction of sediments due to sorting effects (Dellwig et al, 2000). Therefore, variations in Ti / K in locations with negligible changes in sediment provenance over time can be ascribed to changes in depositional energy and sediment transport processes (Piva et al, 2008;Spofforth et al, 2008), whereby an increase in the ratio denotes amplified bottom water currents.…”

Section: Study Locationmentioning

confidence: 99%

A 1500-year multiproxy record of coastal hypoxia from the northern Baltic Sea indicates unprecedented deoxygenation over the 20th century

et al. 2018

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Abstract. The anthropogenically forced expansion of coastal hypoxia is a major environmental problem affecting coastal ecosystems and biogeochemical cycles throughout the world. The Baltic Sea is a semi-enclosed shelf sea whose central deep basins have been highly prone to deoxygenation during its Holocene history, as shown previously by numerous paleoenvironmental studies. However, long-term data on past fluctuations in the intensity of hypoxia in the coastal zone of the Baltic Sea are largely lacking, despite the significant role of these areas in retaining nutrients derived from the catchment. Here we present a 1500-year multiproxy record of near-bottom water redox changes from the coastal zone of the northern Baltic Sea, encompassing the climatic phases of the Medieval Climate Anomaly (MCA), the Little Ice Age (LIA), and the Modern Warm Period (MoWP). Our reconstruction shows that although multicentennial climate variability has modulated the depositional conditions and delivery of organic matter (OM) to the basin the modern aggravation of coastal hypoxia is unprecedented and, in addition to gradual changes in the basin configuration, it must have been forced by excess human-induced nutrient loading. Alongside the anthropogenic nutrient input, the progressive deoxygenation since the beginning of the 1900s was fueled by the combined effects of gradual shoaling of the basin and warming climate, which amplified sediment focusing and increased the vulnerability to hypoxia. Importantly, the eutrophication of coastal waters in our study area began decades earlier than previously thought, leading to a marked aggravation of hypoxia in the 1950s. We find no evidence of similar anthropogenic forcing during the MCA. These results have implications for the assessment of reference conditions for coastal water quality. Furthermore, this study highlights the need for combined use of sedimentological, ichnological, and geochemical proxies in order to robustly reconstruct subtle redox shifts especially in dynamic, non-euxinic coastal settings with strong seasonal contrasts in the bottom water quality.

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Changing sedimentation in tidal flat sediments of the southern North Sea from the Holocene to the present: a geochemical approach

Cited by 86 publications

References 12 publications

Sedimentary environment changes during the Early-Middle Pleistocene transition as recorded by the Daumantai sections in Lithuania

Sedimentary environment changes during the Early-Middle Pleistocene transition as recorded by the Daumantai sections in Lithuania

Microphytobenthic dynamics in a Wadden Sea intertidal flat – Part II: Seasonal and spatial variability of non-diatom community components in relation to abiotic parameters

A 1500-year multiproxy record of coastal hypoxia from the northern Baltic Sea indicates unprecedented deoxygenation over the 20th century

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