Coastal signals of environmental changes: foraminifera as benthic monitors

Climate changes, tightly linked to anthropogenic activities, are significantly altering environments and ecosystems globally, such as by increasing marine and coastal deoxygenation or occurrences of extreme weather events. The significance of paleoenvironmental and -climate reconstructions, as well as monitoring of current conditions, for unravelling baseline natural variation, today’s changes and potential future impacts, has been recognised by the Intergovernmental Panel on Climate Change (IPCC) reports. However, to access past records of physical and chemical environmental variables, and comprehensively assess ecosystem reactions, reliable and sensitive proxies are critical. This thesis’ focus lies on benthic foraminifera—unicellular protists with mineralised or organic test, abundantly inhabiting ocean and coastal sediments—and their calibration as indicator for a variety of environmental conditions in field-sampling approaches. The research projects follow two general strategic tracks: (I) a biogeochemical assessment of trace-elemental ratios in foraminiferal calcium-carbonate tests using high-resolution, micro-analytical techniques; (II) a molecular approach investigating foraminiferal environmental DNA derived from coastal sediments. Papers I and II concern the calibration of the benthic foraminiferal Mn/Ca proxy for marine oxygenation conditions in modern field studies. Trace-element concentrations and distributions were measured by plasma-, laser- and synchrotron-based analyses in a high-resolution, individual-foraminifera approach, and interpreted in the context of ambient physical and chemical conditions of the water column, pore-waters and sediments (including oxygen and manganese concentrations). Investigating two coastal systems with almost permanently severely oxygen-deficient bottom-waters (Santa Barbara Basin, Paper I), and undergoing a seasonal oxygenation cycle across the low- to well-oxygenated range (Gullmar Fjord, Paper II), respectively, demonstrated the utility of the Mn/Ca proxy for indicating low-oxygen conditions specifically. Continued calibration efforts under consideration of ambient oxygenation and redox regimes may open further possibilities of quantitative oxygen reconstructions. Paper III explores the use of coastal, benthic Ba/Ca records as indicator of riverine runoff and drought on land across the years 2018 and 2019, characterised by severe heat and drought, and warm and wet conditions, respectively. Benthic Ba/Ca correlated significantly with the hydroclimate conditions, as inferred from extensive meteorological and hydrological data sets of the region, highlighting qualitative proxy potential for paleo-drought reconstructions. Based on ambient sediment and pore-water geochemistry, we discuss mediation of water-column transport and pore-water Ba cycling by Fe and Mn oxides. All three investigations of these geochemical proxies (Paper I–III) highlighted the significance of biological controls on foraminiferal TE/Ca, which are species-specific and, thus, should be a deciding factor in choosing proxy candidate species. In particular the influences of micro-habitat distribution and utilised metabolic pathways by foraminifera are discussed in detail. In Paper IV foraminiferal biodiversity and assemblage responses to natural and anthropogenic environmental trends in a fjord system (Swedish west coast) are documented in a metabarcoding approach. Environmental DNA successfully tracked biodiversity and community composition changes associated with contrasting ecosystems but showed damped sensitivity to environmental variability on sub-annual time-scales. Overlaps and discrepancies between molecular and traditional, observation-based assessment techniques, as well as future trajectories to resolve uncertainties are discussed. Overall, this thesis solidifies and expands the currently available proxy toolbox for reconstructions of both coastal low-oxygen, as well as terrestrial hydroclimate conditions. The findings contribute towards filling current knowledge gaps pertaining to biotic impacts on foraminifera-derived biogeochemical signals and methodological uncertainties in metabarcoding approaches and highlight the significance of implementing molecular techniques in conventional foraminiferal assemblage studies

Drought recorded by Ba/Ca in coastal benthic foraminifera

Increasing occurrences of extreme weather events, such as the 2018 drought over northern Europe, are a concerning issue under global climate change. High-resolution archives of natural hydroclimate proxies, such as rapidly accumulating sediments containing biogenic carbonates, offer the potential to investigate the frequency and mechanisms of such events in the past. Droughts alter the barium (Ba) concentration of near-continent seawater through the reduction in Ba input from terrestrial runoff, which in turn may be recorded as changes in the chemical composition (Ba/Ca) of foraminiferal calcium carbonates accumulating in sediments. However, so far the use of Ba/Ca as a discharge indicator has been restricted to planktonic foraminifera, despite the high relative abundance of benthic species in coastal, shallow-water sites. Moreover, benthic foraminiferal Ba/Ca has mainly been used in openocean records as a proxy for paleo-productivity. Here we report on a new geochemical data set measured from living (CTG-labeled) benthic foraminiferal species to investigate the capability of benthic Ba/Ca to record changes in river runoff over a gradient of contrasting hydroclimatic conditions. Individual foraminifera (Bulimina marginata, Non-ionellina labradorica) were analyzed by laser-ablation ICP-MS over a seasonal and spatial gradient within Gullmar Fjord, Swedish west coast, during 2018-2019. The results are compared to an extensive meteorological and hydrological data set, as well as sediment and pore-water geochemistry. Benthic foraminiferal Ba/Ca correlates significantly to riverine runoff; however, the signals contain both spatial trends with distance to Ba source and species-specific influences such as micro-habitat preferences. We deduce that shallow-infaunal foraminifera are especially suitable as proxy for terrestrial Ba input and discuss the potential influence of water-column and pore-water Ba cycling. While distance to Ba source, water depth, pore-water geochemistry, and species-specific effects need to be considered in interpreting the data, our results demonstrate confidence in the use of Ba/Ca of benthic foraminifera from near-continent records as a proxy for past riverine discharge and to identify periods of drought.Peer reviewe

BeppoSAX/PDS serendipitous detections at high galactic latitudes

At a flux limit of ~10^(-11) erg/cm2/s in the 20-100 keV band, the PDS instrument on-board BeppoSAX offers the opportunity to study the extragalactic sky with an unprecedented sensitivity. In this work we report on the results of a search in the BeppoSAX archive for serendipitous high energy sources at high galactic latitudes (|b| > 13 deg). We have defined a set of twelve regions in which the PDS/MECS cross-calibration constant is higher than the nominal value. We attribute this mismatch to the presence of a serendipitous source in the PDS field of view.In four cases the likely high energy emitter is also present in the MECS field of view. In these cases, we have performed a broad band spectral analysis (1.5-100 keV) so as to understand the source spectral behaviour and compare it with previous BeppoSAX observations when available. In eight cases the identification of the source likely to provide the PDS spectrum is based on indirect evidence (extrapolation to lower energies and/or comparison to previous observations). This approach leads to the discovery of six new hard X-ray emitting objects (PKS 2356-611, 2MASX J14585116-1652223, NGC 1566, NGC 7319, PKS 0101-649 and ESO 025-G002) and to the presentation the PDS spectrum of NGC 3227 for the first time. In the remaining five cases we provide extra BeppoSAX observations that can be compared with measurements which are already published and/or in the archive.Comment: 16 pages, 9 figures, accepted for publication in A&A, main journa

Spårämnesdata (Mn/Ca, Mg/Ca, Sr/Ca) från den bottenlevande foraminiferarten Nonionella stella, provtagen i ytsediment från Santa Barbara bassängen, USA - Trace-elemental data (Mn/Ca, Mg/Ca, Sr/Ca) of the benthic foraminifer Nonionella stella from core-top sediments of the Santa Barbara Basin, USA

Dataset of Mn/Ca, Mg/Ca and Sr/Ca of the three most-recently formed chambers (n, n-1 and n-2) of Nonionella stella (CTG-labelled) acquired by Secondary Ion Mass Spectrometry (SIMS; Nordsim, Stockholm, Sweden). Nonionella stella specimens were collected from core-top samples of three sites over a depth-gradient in the Santa Barbara Basin, off Southern California, USA. The data set is part of a study exploring the response of foraminiferal Mn/Ca to changing bottom-water oxygenation and pore-water Mn geochemistry. The data is discussed in: Brinkmann, I., Ni, S., Schweizer, M., Oldham, V. E., Quintana Krupinski, N. B., Medjoubi, K., et al. (2021). Foraminiferal Mn/Ca as bottom-water hypoxia proxy: An assessment of Nonionella stella in the Santa Barbara Basin, USA. Paleoceanography and Paleoclimatology, 36, e2020PA004167. https://doi.org/10.1029/2020PA004167. Please contact the main author for further details ([email protected]). The northern SBB was sampled in May 2018 (cruise SP1811, R/V Robert Gordon Sproul) at site 1 (430 m; 34º 18.6’N, 119º 54.0’W), site 2 (505 m; 34º 20.8’N, 119º 59.0’W) and site 3 (567 m; 34º 19.2’N, 120º 03.4’W). Sediment cores were recovered with a Ocean Instruments MC800 multicorer. The cores were sliced into 0.5 cm sections (‘0–0.5 cm’, ‘0.5–1.0 cm’, ‘1.0–1.5 cm’ and ‘1.5–2.0 cm’; site 1 also 'fluff') and CTG-labelled to identify living foraminifera. Nonionella stella specimens were selected and bleached (NaOCl 5%) prior to epoxy-embedding. Trace element concentrations of test walls were analysed using a CAMECA ims1280 ion microprobe (Nordsim Laboratory, Swedish Museum of Natural History, Stockholm, Sweden); an OKA calcite crystal served as reference material.Dataset över Mn/Ca, Mg/Ca and Sr/Ca från de tre senaste bildade kamrarna (n, n-1, n-2) i skal av Nonionella stella, analyserade genom en jonmikrosond (SIMS; Nordsim, Stockholm, Sverige). Nonionella stella individer provtogs från ytsediment från tre stationer över en djupgradient i Santa Barbara bassängen, södra Kalifornien, USA. Datasetet är en del av en studie för att undersöka hur Mn/Ca kvoten i foraminiferers skal ändras med ändrad syrgaskoncentration. Publikationen där detta dataset ingår finns på https://doi.org/10.1029/2020PA004167. Kontakta huvudförfattaren för fler detaljer ([email protected]). För att använda datasetet måste källa anges. Norra delen av Santa Barbara bassängen provtogs i maj 2018 (expedition SP1811, R/V Robert Gordon Sproul), station 1 (430 m vattendjup; 34º 18.6’N, 119º 54.0’W), station 2 (505 m; 34º 20.8’N, 119º 59.0’W) och station 3 (567 m; 34º 19.2’N, 120º 03.4’W). Sedimenten provtogs med en Ocean Instruments MC800 multicorer. Sedimentkärnorna skivades till 0,5 cm tjocka skivor (‘0–0.5 cm’, ‘0.5–1.0 cm’, ‘1.0–1.5 cm’ and ‘1.5–2.0 cm’; station 1 även det lösa organiska ”fluffet” på överytan'). CTG tillsattes för att särskilja mellan levande och döda foraminiferer. Utvalda (nu döda) individer blektes (NaOCl 5%) innan de bäddades in i epoxy. Koncentrationerna av spårelementinnehållet i skalväggen analyserades genom att använda en CAMECA ims1280 jon mikrosond (Nordsim Laboratory, Swedish Museum of Natural History, Stockholm, Sweden)

Spårämnesdata (Mn/Ca) från bottenlevande foraminiferer, provtagna i ytsediment från Gullmarsfjorden, Sverige

Dataset of Mn/Ca in Bulimina marginata and Nonionellina labradorica (CTG-labelled) acquired by Laser-Ablation Inductively Coupled Mass Spectrometry (LA-ICP-MS). Comprises data of the three most-recently formed chambers (n, n-1 and n-2), as well as the proloculus area (p; B. marginata only). The specimens were collected from core-top samples of two sites in the fjord Gullmarn on the west coast of Sweden over a temporal gradient spanning the years 2018 and 2019. The data set is part of a study exploring the response of foraminiferal Mn/Ca to low-oxygen bottom-water conditions. Sediment from the fjord Gullmarn was sampled in September 2018, February 2019 and June 2019 (R/V Oscar von Sydow and R/V Skagerak, respectively) at two sites: GF 117 (115–117 m water depth; 58º19.695’N, 11º33.147’E) and GF 71 (69–71 m water depth; 58º17.116’N, 11º30.546’E). Sediment cores were recovered with a GEMAX® twin-barrel corer (modified Gemini corer, 9 cm diameter, from Oy Kart AB, Finland). The top 0-1 and 1-2 cm of the cores were collected and CTG-labelled to identify living foraminifera. Bulimina marginata and Nonionellina labradorica specimens were selected and bleached (NaOCl 5%). Trace element concentrations of test walls were analysed using a Bruker Aurora Elite (quadrupole) ICP‐MS and a 193 nm Cetac Analyte G2 excimer laser installed with a two volume HelEx2 sample cell (Dept. of Geology, Lund University, Lund, Sweden). U.S. National Institute of Standards and Technology SRM NIST610 was used as external calibration material with GeoReM (Geological and Environmental Reference Materials; Jochum et al., 2005) composition values (via http://georem.mpch-mainz.gwdg.de). Please contact the main author for further details.Dataset över Mn/Ca i skal av Bulimina marginata och Nonionellina labradorica (CTG-märkta) analyserades genom laserspektroskopi (LA-ICP-MS). Mn/Ca mättes i de tre senast bildade kamrarna (n, n-1, n-2), och i skal av Bulimina marginata analyserades även de första kamrarna, så kallade 'proloculus' (p). Exemplaren provtogs från ytsediment från två platser i Gullmarsfjorden under 2018 och 2019. Datasetet är en del av en studie som undersöker hur Mn/Ca kvoten i foraminiferers skal påverkas av förändrad syrehalt i bottenvatten. Sediment från Gullmarsfjorden provtogs i september 2018, februari 2019 och juni 2019 (R/V Oscar von Sydow respektive R/V Skagerak) på två platser: GF 117 (115–117 m vattendjup; 58º19.695’N, 11º33.147’E) och GF 71 (69–71 m vattendjup; 58º17.116’N, 11º30.546’E). Proven togs med en GEMAX® twin-barrel corer (modifierad Gemini corer, 9 cm diameter, från Oy Kart AB, Finland). Sedimentprov togs från ytan av sedimentkärnorna (0-1 cm och 1-2 cm) och CTG tillsattes för att särskilja mellan levande och döda foraminiferer. Utvalda (nu döda) exemplar blektes (NaOCl 5%) innan analyserna. Koncentrationerna av spårelementinnehållet i skalväggen analyserades med laserspektroskopi (LA-ICP-MS; geologiska institutionen, Lunds universitet, Lund, Sverige). För ytterligare information, se den engelska katalogposten

Spårämnesdata (Ba/Ca) från bottenlevande foraminiferer, provtagna i ytsediment från Gullmarsfjorden, Sverige.

Dataset of Ba/Ca in Bulimina marginata and Nonionellina labradorica (CTG-labelled) acquired by Laser-Ablation Inductively Coupled Mass Spectrometry (LA ICP MS; Department of Geology, Lund University, Lund, Sweden). Comprises data of the three most-recently formed chambers (n, n-1 and n-2), as well as the proloculus area (p; B. marginata only). The specimens were collected from core-top samples of two sites in Gullmar Fjord, Swedish West coast, Sweden over a temporal gradient spanning the year 2018 and 2019. The data set is part of a study exploring the response of foraminiferal Ba/Ca to contrasting hydroclimatic conditions. A publication including this data is currently ongoing. Please contact the main author for further details ([email protected]). Gullmar Fjord was sampled in September 2018, February 2019 and June 2019 (R/V Oscar von Sydow and R/V Skagerak, respectively) at GF 117 (115–117 m; 58º19.695’N, 11º33.147’E) and GF 71 (69–71 m; 58º17.116’N, 11º30.546’E). Sediment cores were recovered with a GEMAX® twin-barrel corer (modified Gemini corer, 9 cm diameter, from Oy Kart AB, Finland). The top 1 cm of the cores were collected and CTG-labelled to identify living foraminifera. Bulimina marginata and Nonionellina labradorica specimens were selected and bleached (NaOCl 5%). Trace element concentrations of test walls were analysed using a Bruker Aurora Elite (quadrupole) ICP‐MS and a 193 nm Cetac Analyte G2 excimer laser installed with a two volume HelEx2 sample cell (Dept. of Geology, Lund University, Lund, Sweden). U.S. National Institute of Standards and Technology SRM NIST610 was used as external calibration material with GeoReM (Geological and Environmental Reference Materials; Jochum et al., 2005) composition values (via http://georem.mpch-mainz.gwdg.de).Dataset över Ba/Ca från de tre senaste bildade kamrarna (n, n-1, n-2) i skal av Bulimina marginata och Nonionellina labradorica, analyserades genom laserspektroskopi (LA ICP MS; geologiska institutionen, Lunds universitet, Lund, Sverige). I skal av Bulimina marginata analyserades även de första kamrarna (p). Individer provtogs från ytsediment från två stationer i Gullmarsfjorden under 2018 och 2019. Datasetet är en del av en studie för att undersöka hur Ba/Ca kvoten i foraminiferers skal ändras med ändrat hydroklimatiskt läge. En publikation där detta dataset ingår är inskickad till granskning. Kontakta huvudförfattaren för fler detaljer. ([email protected]). För att använda datasetet måste källa anges. Gullmarsfjorden provtogs i september 2018, februari 2019 och juni 2019 (R/V Oscar von Sydow och R/V Skagerak), GF 117 (115–117 m vattendjup; 58º19.695’N, 11º33.147’Ö) och GF 71 (69–71 m vattendjup; 58º17.116’N, 11º30.546’Ö). Sedimenten provtogs med en GEMAX® twin-barrel corer (modifierad Gemini corer, 9 cm diameter, från Oy Kart AB, Finland). Sedimentprover togs från ytan av sedimentkärnorna (1 cm) och CTG tillsattes för att särskilja mellan levande och döda foraminiferer. Utvalda (nu döda) individer blev blekta (NaOCl 5%) innan analyserna. Koncentrationerna av spårelementinnehållet i skalväggen analyserades genom laserspektroskopi (LA ICP MS; geologiska institutionen, Lunds universitet, Lund, Sverige)

Revisiting the applicability and constraints of molybdenum and uranium-based paleo redox proxies: comparing two contrasting sill fjords

Peer reviewe

Through the e DNA looking glass: Responses of fjord benthic foraminiferal communities to contrasting environmental conditions

The health of coastal marine environments is severely declining with globalchanges. Proxies, such as those based on microeukaryote communities, canrecord biodiversity and ecosystem responses. However, conventional studiesrely on microscopic observations of limited taxonomic range and size fraction,missing putatively ecologically informative community components. Here, wetested molecular tools to survey foraminiferal biodiversity in a fjord system(Sweden) on spatial and temporal scales: Alpha and beta diversity responses tonatural and anthropogenic environmental trends were assessed and variabilityof foraminiferal environmental DNA (eDNA) compared to morphology-baseddata. The identification of eDNA-obtainedtaxonomic units was aidedby single-cellbarcoding. Our study revealed wide diversity, including typicalmorphospecies recognized in the fjords, and so-farunrecognized taxa. DNAextraction method impacted community composition outputs significantly.DNA extractions of 10 g sediment more reliably represented present diversitythan of 0.5-gsamples and, thus, are preferred for environmental assessmentsin this region. Alpha-andbeta diversity of 10-gextracts correlated withbottom-watersalinity similar to morpho-assemblagediversity changes. Sub-annualenvironmental variability resolved only partially, indicating dampedsensitivity of foraminiferal communities on short timescales using establishedmetabarcoding techniques. Systematically addressing the current limitationsof morphology-basedand metabarcoding studies may strongly improve futurebiodiversity and environmental assessments

Benthic Foraminiferal Mn/Ca as Low-Oxygen Proxy in Fjord Sediments

Peer reviewe

Foraminiferal Mn/Ca as bottom-water hypoxia proxy: an assessment of Nonionella stella in the Santa Barbara Basin, USA

© The Author(s), 2021. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Brinkmann, I., Ni, S., Schweizer, M., Oldham, V. E., Quintana Krupinski, N. B., Medjoubi, K., Somogyi, A., Whitehouse, M. J., Hansel, C. M., Barras, C., Bernhard, J. M., & Filipsson, H. L. Foraminiferal Mn/Ca as bottom-water hypoxia proxy: an assessment of Nonionella stella in the Santa Barbara Basin, USA. Paleoceanography and Paleoclimatology, 36(11), (2021): e2020PA004167, https://doi.org/10.1029/2020PA004167.Hypoxia is of increasing concern in marine areas, calling for a better understanding of mechanisms leading to decreasing dissolved oxygen concentrations ([O2]). Much can be learned about the processes and implications of deoxygenation for marine ecosystems using proxy records from low-oxygen sites, provided proxies, such as the manganese (Mn) to calcium (Ca) ratio in benthic foraminiferal calcite, are available and well calibrated. Here we report a modern geochemical data set from three hypoxic sites within the Santa Barbara Basin (SBB), USA, where we study the response of Mn/Caforam in the benthic foraminifer Nonionella stella to variations in sedimentary redox conditions (Mn, Fe) and bottom-water dissolved [O2]. We combine molecular species identification by small subunit rDNA sequencing with morphological characterization and assign the SBB N. stella used here to a new phylotype (T6). Synchrotron-based scanning X-ray fluorescence (XRF) imaging and Secondary Ion Mass Spectrometry (SIMS) show low Mn incorporation (partition coefficient DMn < 0.05) and limited proxy sensitivity of N. stella, at least within the range of dissolved [O2] (2.7–9.6 μmol/l) and Mnpore-water gradients (2.12–21.59 μmol/l). Notably, even though intra- and interspecimen Mn/Ca variability (33% and 58%, respectively) was only partially controlled by the environment, Mn/Caforam significantly correlated with both pore-water Mn and bottom-water [O2]. However, the prevalent suboxic bottom-water conditions and limited dissolved [O2] range complicate the interpretation of trace-elemental trends. Additional work involving other oxygenation proxies and samples from a wider oxygen gradient should be pursued to further develop foraminiferal Mn/Ca as an indicator for hypoxic conditions.We acknowledge funding from the Swedish Research Council VR (grant numbers 2017-04190 and 2017-00671), the Crafoord Foundation, and the Royal Physiographic Society in Lund, Sweden. Shiptime provided by US NSF IOS 1557430. We acknowledge SOLEIL for provision of synchrotron radiation facilities and the beamline NANOSCOPIUM (proposal number 20181115). The synchrotron-based experiments were supported by CALIPSOplus under the EU Framework Programme for Research and Innovation HORIZON 2020 (grant agreement 730872). The SIMS analyses were jointly supported by the Swedish Museum of Natural History and Swedish Research Council. This is NordSIMS contribution No. 694. J. M. Bernhard and C. M. Hansel also acknowledge funding from the US National Science Foundation (IOS 1557430)