| 1. |
- Bird, Clare, et al.
(författare)
-
The genetic diversity, morphology, biogeography, and taxonomic designations of Ammonia (Foraminifera) in the Northeast Atlantic
- 2020
-
Ingår i: Marine Micropaleontology. - : Elsevier BV. - 0377-8398.
-
Tidskriftsartikel (refereegranskat)abstract
- The genetic diversity, morphology and biogeography of Ammonia specimens was investigated across the Northeast (NE) Atlantic margins, to enhance the regional (palaeo)ecological studies based on this genus. Living specimens were collected from 22 sampling locations ranging from Shetland to Portugal to determine the distribution of Ammonia genetic types across the NE Atlantic shelf biomes. We successfully imaged (via scanning electron microscopy, SEM) and genotyped 378 Ammonia specimens, based on the small subunit (SSU) rRNA gene, linking morphology to genetic type. Phylogenetic analyses enabled identification of seven genetic types and subtypes inhabiting the NE Atlantic margins. Where possible, we linked SSU genetic types to the established large subunit (LSU) T-type nomenclature of Hayward et al. (2004). SSU genetic types with no matching T-type LSU gene sequences in GenBank were allocated new T-numbers to bring them in line with the widely adopted T-type nomenclature. The genetic types identified in the NE Atlantic margins are T1, T2, T3, T6, and T15, with both T2 and T3 being split further into the subtypes T2A and T2B, and T3S and T3V respectively. The seven genetic types and subtypes exhibit different biogeographical distributions and/or ecological preferences, but co-occurrence of two or more genetic types is common. A shore-line transect at Dartmouth (South England) demonstrates that sampling position on shore (high, middle or low shore) influences the genetic type collected, the numbers of genetic types that co-occur, and the numbers of individuals collected. We performed morphometric analysis on the SEM images of 158 genotyped Ammonia specimens. T15 and the subtypes T3S and T3V can be morphologically distinguished. We can unequivocally assign the taxonomic names A. batava and A. falsobeccarii to T3S and T15, respectively. However, the end members of T1, T2A, T2B and T6 cannot be unambiguously distinguished, and therefore these genetic types are partially cryptic. However, we confirm that T2A can be assigned to A. aberdoveyensis, but caution must be taken in warm provinces where the presence of T2B will complicate the morphological identification of T2A. We suggest that T6 should not currently be allocated to the Pliocene species A. aomoriensis due to morphological discrepancies with the taxonomic description and to the lack of genetic information. Of significance is that these partially cryptic genetic types frequently co-occur, which has considerable implications for precise species identification and accurate data interpretation.
|
|
| 2. |
- Brinkmann, Inda, et al.
(författare)
-
Benthic Foraminiferal Mn/Ca as Low-Oxygen Proxy in Fjord Sediments
- 2023
-
Ingår i: Global Biogeochemical Cycles. - 0886-6236. ; 37:5
-
Tidskriftsartikel (refereegranskat)abstract
- Fjord systems are typically affected by low-oxygen conditions, which are increasing in extent and severity, forced by ongoing global changes. Fjord sedimentary records can provide high temporal resolution archives to aid our understanding of the underlying mechanisms and impacts of current deoxygenation. However, such archives can only be interpreted with well-calibrated proxies. Bottom-water oxygen conditions determine redox regime and availability of redox-sensitive trace elements such as manganese, which in turn may be recorded by manganese-to-calcium ratios (Mn/Ca) in biogenic calcium carbonates (e.g., benthic foraminifera tests). However, biological influences on Mn incorporation (e.g., species-specific Mn fractionation, ontogeny, living and calcification depths) are still poorly constrained. We analyzed Mn/Ca of living benthic foraminifera (Bulimina marginata, Nonionellina labradorica), sampled at low- to well-oxygenated conditions over a seasonal gradient in Gullmar Fjord, Swedish West coast (71–217 μmol/L oxygen (O2)), by laser-ablation ICP-MS. High pore-water Mn availability in the fjord supported Mn incorporation by foraminifera. B. marginata recorded contrasting Mn redox regimes sensitively and demonstrated potential as proxy for low-oxygen conditions. Synchrotron-based scanning X-ray fluorescence nanoimaging of Mn distributions across B. marginata tests displayed Mn/Ca shifts by chambers, reflecting bottom-water oxygenation history and/or ontogeny-driven life strategy preferences. In contrast, Mn/Ca signals of N. labradorica were extremely high and insensitive to environmental variability. We explore potential biologically controlled mechanisms that could potentially explain this species-specific response. Our data suggest that with the selection of sensitive candidate species, the Mn/Ca proxy has potential to be further developed for quantitative oxygen reconstructions in the low-oxygen range.
|
|
| 3. |
- Brinkmann, Inda, et al.
(författare)
-
Drought recorded by Ba/Ca in coastal benthic foraminifera
- 2022
-
Ingår i: Biogeosciences. - : Copernicus GmbH. - 1726-4170 .- 1726-4189. ; 19:9, s. 2523-2535
-
Tidskriftsartikel (refereegranskat)abstract
- 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 open-ocean 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, Nonionellina 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.
|
|
| 4. |
- Brinkmann, Inda, et al.
(författare)
-
Through the eDNA looking glass: Responses of fjord benthic foraminiferal communities to contrasting environmental conditions
- 2023
-
Ingår i: Journal of Eukaryotic Microbiology. - : Wiley. - 1066-5234 .- 1550-7408. ; 70:4
-
Tidskriftsartikel (refereegranskat)abstract
- The health of coastal marine environments is severely declining with global changes. Proxies, such as those based on microeukaryote communities, can record biodiversity and ecosystem responses. However, conventional studies rely on microscopic observations of limited taxonomic range and size fraction, missing putatively ecologically informative community components. Here, we tested molecular tools to survey foraminiferal biodiversity in a fjord system (Sweden) on spatial and temporal scales: Alpha and beta diversity responses to natural and anthropogenic environmental trends were assessed and variability of foraminiferal environmental DNA (eDNA) compared to morphology-based data. The identification of eDNA-obtained taxonomic units was aided by single-cell barcoding. Our study revealed wide diversity, including typical morphospecies recognized in the fjords, and so-far unrecognized taxa. DNA extraction method impacted community composition outputs significantly. DNA extractions of 10 g sediment more reliably represented present diversity than of 0.5-g samples and, thus, are preferred for environmental assessments in this region. Alpha- and beta diversity of 10-g extracts correlated with bottom-water salinity similar to morpho-assemblage diversity changes. Sub-annual environmental variability resolved only partially, indicating damped sensitivity of foraminiferal communities on short timescales using established metabarcoding techniques. Systematically addressing the current limitations of morphology-based and metabarcoding studies may strongly improve future biodiversity and environmental assessments.
|
|
| 5. |
- Darling, Kate F., et al.
(författare)
-
The genetic diversity, phylogeography and morphology of Elphidiidae (Foraminifera) in the Northeast Atlantic
- 2016
-
Ingår i: Marine Micropaleontology. - : Elsevier BV. - 0377-8398. ; 129, s. 1-23
-
Tidskriftsartikel (refereegranskat)abstract
- Genetic characterisation (SSU rRNA genotyping) and Scanning Electron Microscope (SEM) imaging of individual tests were used in tandem to determine the modern species richness of the foraminiferal family Elphidiidae (Elphidium, Haynesina and related genera) across the Northeast Atlantic shelf biomes. Specimens were collected at 25 locations from the High Arctic to Iberia, and a total of 1013 individual specimens were successfully SEM imaged and genotyped. Phylogenetic analyses were carried out in combination with 28 other elphidiid sequences from GenBank and seventeen distinct elphidiid genetic types were identified within the sample set, seven being sequenced for the first time. Genetic types cluster into seven main clades which largely represent their general morphological character. Differences between genetic types at the genetic, morphological and biogeographic levels are indicative of species level distinction. Their biogeographic distributions, in combination with elphidiid SSU sequences from GenBank and high resolution images from the literature show that each of them exhibits species-specific rather than clade-specific biogeographies. Due to taxonomic uncertainty and divergent taxonomic concepts between schools, we believe that morphospecies names should not be placed onto molecular phylogenies unless both the morphology and genetic type have been linked to the formally named holotype, or equivalent. Based on strict morphological criteria, we advocate using only a three-stage approach to taxonomy for practical application in micropalaeontological studies. It comprises genotyping, the production of a formal morphological description of the SEM images associated with the genetic type and then the allocation of the most appropriate taxonomic name by comparison with the formal type description. Using this approach, we were able to apply taxonomic names to fifteen genetic types. One of the remaining two may be potentially cryptic, and one is undescribed in the literature. In general, the phylogeographic distribution is in agreement with our knowledge of the ecology and biogeographical distribution of the corresponding morphospecies, highlighting the generally robust taxonomic framework of the Elphidiidae in time and space.
|
|
| 6. |
- Deldicq, Noémie, et al.
(författare)
-
History of the introduction of a species resembling the benthic foraminifera Nonionella stella in the Oslofjord (Norway): morphological, molecular and paleo-ecological evidences
- 2019
-
Ingår i: Aquatic Invasions. - : Regional Euro-Asian Biological Invasions Centre Oy (REABIC). - 1818-5487. ; 14:2, s. 182-205
-
Tidskriftsartikel (refereegranskat)abstract
- Specimens resembling the benthic foraminifera Nonionella stella (Cushman and Moyer, 1930), a morphospecies originally described from the San Pedro Basin, California, USA, were observed for the first time in the Oslofjord (Norway) in 2012. This study investigates the Oslofjord Nonionella population in order to confirm its nonindigenous species (NIS) status and assess its introduction time. Morphological characterisation based on SEM imaging complemented by molecular identification using small subunit (SSU) rDNA sequencing and assessment of the recent past record (sediment core), were performed on material collected in the Oslofjord in 2016. Examination of the dead fauna showed that specimens resembling N. stella only appeared recently in the Oslofjord, confirming the NIS status of this population. Moreover, DNA results indicate that the Oslofjord specimens differ genetically from N. stella sampled in the Santa Barbara Basin (California USA). Hence, we propose to use the name Nonionella sp. T1 for the specimens sampled in the Oslofjord for the time being. In the southern part of the Skagerrak, specimens morphologically similar to Nonionella sp. T1 were reported as NIS in the Gullmar fjord (Sweden) in 2011 and in the Skagerrak in 2015. Molecular data indicate that the two populations from Gullmar- and Oslofjords are identical, based on their SSU rDNA sequences. In addition, analyses of foraminiferal dead assemblages suggest that the population from the Gullmar fjord settled prior to the Oslofjord population, i.e. ~ 1985 and about 2010, respectively. This implies that Nonionella sp. T1 may have been transported from Sweden to Norway by northward coastal currents.
|
|
| 7. |
- Filipsson, Helena L., et al.
(författare)
-
Geochemical composition of Baltic benthic foraminifera collected and cultured over a large salinity gradient.
- 2017
-
Konferensbidrag (refereegranskat)abstract
- Some of the most significant challenges in paleoclimate research arise from the need to both understand and reduce the uncertainty associated with proxies for climate reconstructions. These challenges were further highlighted in connection with the IODP Exp.347 Baltic Sea Paleoenvironment. We have investigated temperature and salinity proxies through a combination of field-and culture-based benthic foraminiferal samplesfrom the Baltic(sal. 14)-Kattegat(sal. 32), together with genetic characterization. Two long-term experiments at twotemperatures and three salinities were performed. We present foraminiferal assemblage,trace element (Mg/Ca, Ba/Ca, Mn/Ca),and stable O and C isotope results from these locations, including LA-ICP-MS data from cultured specimens. Furthermore, specimens of Elphidium and Ammonia were genetically characterized; the results indicate that the same genetic type of Elphidiumis found in both salinity regimes, but that the Ammoniagenetic types differ depending on the prevailing salinity regime.
|
|
| 8. |
- Groeneveld, Jeroen, et al.
(författare)
-
Assessing proxy signatures of temperature, salinity, and hypoxia in the Baltic Sea through foraminifera-based geochemistry and faunal assemblages
- 2018
-
Ingår i: Journal of Micropalaeontology. - : Copernicus GmbH. - 0262-821X .- 2041-4978. ; 37:2, s. 403-429
-
Tidskriftsartikel (refereegranskat)abstract
- Current climate and environmental changes strongly affect shallow marine and coastal areas like the Baltic Sea. This has created a need for a context to understand the severity and potential outcomes of such changes. The context can be derived from paleoenvironmental records during periods when comparable events happened in the past. In this study, we explore how varying bottom water conditions across a large hydrographic gradient in the Baltic Sea affect benthic foraminiferal faunal assemblages and the geochemical composition of their calcite tests. We have conducted both morphological and molecular analyses of the faunas and we evaluate how the chemical signatures of the bottom waters are recorded in the tests of several species of benthic foraminifera. We focus on two locations, one in the Kattegat (western Baltic Sea) and one in Hanö Bay (southern Baltic Sea). We show that seawater Mn-•Ca, Mg-•Ca, and Ba-•Ca (Mn-•Casw, Mg-•Casw, and Ba-•Casw) variations are mainly controlled by dissolved oxygen concentration and salinity. Their respective imprints on the foraminiferal calcite demonstrate the potential of Mn-•Ca as a proxy for hypoxic conditions, and Ba-•Ca as a proxy for salinity in enclosed basins such as the Baltic Sea. The traditional use of Mg-•Ca as a proxy to reconstruct past seawater temperatures is not recommended in the region, as it may be overprinted by the large variations in salinity (specifically on Bulimina marginata), Mg-•Casw, and possibly also the carbonate system. Salinity is the main factor controlling the faunal assemblages: a much more diverse fauna occurs in the higher-salinity (- 32) Kattegat than in the low-salinity (- 15) Hanö Bay. Molecular identification shows that only Elphidium clavatum occurs at both locations, but other genetic types of both genera Elphidium and Ammonia are restricted to either low- or high-salinity locations. The combination of foraminiferal geochemistry and environmental parameters demonstrates that in a highly variable setting like the Baltic Sea, it is possible to separate different environmental impacts on the foraminiferal assemblages and therefore use Mn-•Ca, Mg-•Ca, and Ba-•Ca to reconstruct how specific conditions may have varied in the past.
|
|
| 9. |
- Jauffrais, Thierry, et al.
(författare)
-
Kleptoplastidic benthic foraminifera from aphotic habitats : insights into assimilation of inorganic C, N and S studied with sub-cellular resolution
- 2019
-
Ingår i: Environmental Microbiology. - : Wiley. - 1462-2912. ; 21:1, s. 125-141
-
Tidskriftsartikel (refereegranskat)abstract
- The assimilation of inorganic compounds in foraminiferal metabolism compared to predation or organic matter assimilation is unknown. Here, we investigate possible inorganic-compound assimilation in Nonionellina labradorica, a common kleptoplastidic benthic foraminifer from Arctic and North Atlantic sublittoral regions. The objectives were to identify the source of the foraminiferal kleptoplasts, assess their photosynthetic functionality in light and darkness and investigate inorganic nitrogen and sulfate assimilation. We used DNA barcoding of a ~ 830 bp fragment from the SSU rDNA to identify the kleptoplasts and correlated transmission electron microscopy and nanometre-scale secondary ion mass spectrometry (TEM-NanoSIMS) isotopic imaging to study 13C-bicarbonate, 15N-ammonium and 34S-sulfate uptake. In addition, respiration rate measurements were determined to assess the response of N. labradorica to light. The DNA sequences established that over 80% of the kleptoplasts belonged to Thalassiosira (with 96%–99% identity), a cosmopolitan planktonic diatom. TEM-NanoSIMS imaging revealed degraded cytoplasm and an absence of 13C assimilation in foraminifera exposed to light. Oxygen measurements showed higher respiration rates under light than dark conditions, and no O2 production was detected. These results indicate that the photosynthetic pathways in N. labradorica are not functional. Furthermore, N. labradorica assimilated both 15N-ammonium and 34S-sulfate into its cytoplasm, which suggests that foraminifera might have several ammonium or sulfate assimilation pathways, involving either the kleptoplasts or bona fide foraminiferal pathway(s) not yet identified.
|
|
| 10. |
- Morin, Filip, et al.
(författare)
-
Hidden aliens: Application of digital PCR to track an exotic foraminifer across the Skagerrak (North Sea) correlates well with traditional morphospecies analysis. : APPLYING DPCR TO TRACK AN EXOTIC FORAMINIFER
- 2023
-
Ingår i: Environmental Microbiology. - 1462-2912 .- 1462-2920. ; 25:11, s. 2321-37
-
Tidskriftsartikel (refereegranskat)abstract
- The problem of invasive species is a well-studied one, but knowledge of free-living unicellular eukaryotic invasive species is lacking. A potentially invasive foraminifer (Rhizaria), Nonionella sp. T1, was recently discovered in the Skagerrak and its fjords. Digital polymerase chain reaction (dPCR) was applied to track the spread of this non-indigenous species using a new dPCR assay (T1-1). The use of dPCR appears highly complementary to traditional hand picking of foraminiferal shells from the sediment, and is far less time-consuming. This study indicates that Nonionella sp. T1 has bypassed the outer Skagerrak strait, instead becoming established in Swedish west coast fjords, constituting up to half of the living foraminiferal community in fjord mouth areas. The ecology of Nonionella sp. T1 and its potential invasive impacts are still largely unknown, but it appears to be an opportunist using several energy sources such as nitrate respiration and kleptoplasty along with a possibly more efficient reproductive strategy to gain an advantage over the native foraminiferal species. Future ecological studies of Nonionella sp. T1 could be aided by dPCR and the novel Nonionella sp. T1-specific T1-1 assay.
|
|
| 11. |
- O'Brien, Phoebe A. J., 1995, et al.
(författare)
-
Environmental quality status assessment of three Swedish west coast fjords by foraminifera-based genetic and morphological approaches.
- 2024
-
Ingår i: TMS – CFFR Joint Foraminifera Spring Meeting, 22-25th May, Köln, Germany. - : The Micropalaeontological Society and Cushman Foundation For Foraminiferal Research.
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Coastal ecosystems with high environmental variability pose a challenge to environmental assessment techniques. Benthic foraminiferal ecology and population dynamics recovered via observations and genetic metabarcoding (eDNA sequencing) are useful tools for ecosystem quality status (EcoQS) assessment. Conventional microscope-based methodology is constrained only to species with fossilization potential, whilst molecular tools have the capacity to detect both dormant stages (propagules) and soft-bodied individuals (monothalamids) but cannot give quantitative estimates. Foraminifera-based diversity and sensitivity indices like Exp(H’bc) and TSI-med respectively have been shown to reliably estimate EcoQS, however given the novelty of molecular techniques applied to biomonitoring, thorough cross-validation with morphological data is still required. To test the ability of eDNA-based EcoQS techniques to detect foraminiferal response to environmental trends we conducted a spatially comparative study of three fjords on the Swedish west coast (permanently oxic Hake Fjord, seasonally hypoxic Gullmar Fjord and long-term anoxic By Fjord). Surface sediment samples (0-3 cm) taken at stations located at the mouth, centre and head of each fjord in September and October of 2021 provided three sediment sample replicates for eDNA and three sediment sample replicates for the foraminiferal assemblage and sediment geochemistry data. We hypothesize that the substantial variation in abiotic factors (DIC, TOC, TN, pigments, pore water nutrients and bottom water oxygen concentration) observed in the three fjords will impact the alpha and beta diversities reported by traditional (morphology-based) and molecular (DNA-based) techniques. The results will show if trends in foraminiferal diversity and EcoQS revealed by morphological and molecular methods will reflect steep environmental gradients observed in the studied fjord systems.
|
|
| 12. |
- Polovodova Asteman, Irina, 1980, et al.
(författare)
-
Distribution of the putative invasive species Nonionella sp. T1 in the Gullmar Fjord – What is its potential contribution to biogeochemical cycles?
- 2023
-
Ingår i: International Congress FORAMS2023, Perugia, Italy 25-30th June 2023.
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Benthic foraminifera, both fossil and living, have been extensively studied in the seasonally hypoxic Gullmar Fjord (Sweden) for decades to decipher hydrographic changes and ecological status. In 2011, a non-indigenous species named Nonionella sp. T1 was discovered in the fjord for the first time. Here, we aim at evaluating its putative invasive behavior and life strategies by combining assemblage analyses of living foraminifera along a fjord transect of surface sediment (0-3 cm) together with four longer sediment cores (0-5 cm) from two stations at 51 m and 117 m water depth. Our results showed that Nonionella sp. T1 collected in the surface sediment in September 2021 and 2022, was present in almost all the transect samples. This species dominated the living foraminiferal assemblages with an abundance between 15 and 72 %, at seven of the eight sites visited. The highest relative and absolute abundances were noted between 39 and 78 m water depth, proximal to the fjord mouth, with a reduced presence towards the deepest station and the fjord head. However, Nonionella sp. T1 was completely absent in the sandy sediments at the shallowest station (1 m water depth). Sediment cores collected in November 2017 and May 2022 revealed that Nonionella sp. T1 exhibited higher abundance at 51 m water depth compared to 117 m. In a previous study, higher densities were observed at the station 51 m below the oxygenated sediment zone (< 2 mm depth), where high nitrate concentrations in pore waters were measured (2017 data). The authors demonstrated that Nonionella sp. T1 respires nitrate and the pool of specimens denitrifies up to 50 % – 100 % of the nitrate in sediment porewaters, revealing its non-negligible contribution to benthic denitrification. The 10-fold higher abundance of Nonionella sp. T1 recorded in 2022 (compared to 2017) supports previous hypotheses about their invasive character and alerts about their important role in the nitrogen cycle of the Gullmar Fjord. The results of this study highlight the need for continued monitoring of this invasive species, its spreading dynamics and ecological/biogeochemical impacts.
|
|
| 13. |
- Polovodova Asteman, Irina, 1980, et al.
(författare)
-
Spreading of an alien benthic foraminifer in the North Sea: a reason to be worried?
- 2023
-
Ingår i: International Congress FORAMS2023, Perugia, Italy, 25-30th June. - Perugia, Italy : Micropress Europe & The Grzybowski Foundation.
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- In the Skagerrak-Kattegat (eastern North Sea), the alien benthic foraminifer Nonionella sp. T1 (previously referred to as “Nonionella stella”) was reported for the first time in 2011 and 2012 in the Swedish and southern Norwegian fjords, respectively. Based on dated sediment cores its first occurrence can be traced back to the 1980s in the Gullmar Fjord, to the 2000s in the Öresund and to 2010 in the Oslofjord. Since then, Nonionella sp T1 has spread all over the Kattegat and coastal Skagerrak, according to sampling campaigns performed between 2016 and 2022. The species is now highly abundant in the entire Kattegat, including the Öresund, as well as in fjord mouths of the seasonally hypoxic Gullmar Fjord, the oxic Hakefjord and the long-term polluted Idefjord as demonstrated by molecular and morphospecies data. At the same time, Nonionella sp T1 is rare to absent in the Baltic Sea, Skagerrak deep basin and in deep fjords of western and northern Norway. This study shows some preliminary results on the species’ present distribution in the study area and raises questions about the driving factors and potential effects on the local biodiversity.
|
|
| 14. |
- Schweizer, Magali, et al.
(författare)
-
Molecular identification of Ammonia and Elphidium species (Foraminifera, Rotaliida) from the Kiel Fjord (SW Baltic Sea) with rDNA sequences
- 2011
-
Ingår i: Helgoland Journal of Marine Research. ; 65, s. 1-10
-
Tidskriftsartikel (refereegranskat)abstract
- Ammonia and Elphidium collected in the Kiel Fjord for the present study were first identified on morphological bases as Ammonia beccarii (Linne´, 1758) and Elphidium excavatum (Terquem, 1876). Phylogenetic analyses based on partial SSU rDNA and LSU rDNA sequences show that Ammonia specimens sampled in the Kiel Fjord belong to the phylotype T6, which has a disjunct distribution (Wadden and Baltic Seas/China and Japan) and has been identified as Ammonia aomoriensis (Asano, 1951). Partial SSU rDNA sequence analyses indicate that Elphidium specimens from the Kiel Fjord belong to the clade E. excavatum, confirming the morphological identification. This clade can be further divided in three subclades. Kiel Fjord Elphidium belong to two of these subclades and were identified morphologically as the subspecies E. excavatum excavatum (Terquem, 1876) and E. e. clavatum Cushman, 1930.
|
|
| 15. |
- Schweizer, Magali, et al.
(författare)
-
Trophic strategies of intertidal foraminifera explored with single-cell microbiome metabarcoding and morphological methods : What is on the menu?
- 2022
-
Ingår i: Ecology and Evolution. - : Wiley. - 2045-7758. ; 12:11
-
Tidskriftsartikel (refereegranskat)abstract
- In mudflats, interactions and transfers of nutrients and secondary metabolites may drive ecosystems and biodiversity. Foraminifera have complex trophic strategies as they often rely on bacteria and eukaryotes or on potential symbionts for carbon and nitrogen resources. The capacity of these protists to use a wide range of adaptive mechanisms requires clarifying the relationships between them and their microbial associates. Here, we investigate the interactions of three foraminiferal species with nearby organisms in situ, by coupling molecular (cloning/Sanger and high-throughput sequencing) and direct counting and morphological identification with microscopy. This coupling allows the identification of the organisms found in or around three foraminiferal species through molecular tools combined with a direct counting of foraminifera and diatoms present in situ through microscopy methods. Depending on foraminiferal species, and in addition to diatom biomass, diatom frustule shape, size and species are key factors driving the abundance and diversity of foraminifera in mudflat habitats. Three different trophic strategies were deduced for the foraminifera investigated in this study: Ammonia sp. T6 has an opportunistic strategy and is feeding on bacteria, nematoda, fungi, and diatoms when abundant; Elphidium oceanense is feeding mainly on diatoms, mixed with other preys when they are less abundant; and Haynesina germanica is feeding almost solely on medium-large pennate diatoms. Although there are limitations due to the lack of species coverage in DNA sequence databases and to the difficulty to compare morphological and molecular data, this study highlights the relevance of combining molecular with morphological tools to study trophic interactions and microbiome communities of protists at the single-cell scale.
|
|
