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Feng Y, Song H, Song H, Wu Y, Li X, Tian L, Dong S, Lei Y, Clapham ME. High extinction risk in large foraminifera during past and future mass extinctions. SCIENCE ADVANCES 2024; 10:eadj8223. [PMID: 39110795 PMCID: PMC11305383 DOI: 10.1126/sciadv.adj8223] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/01/2023] [Revised: 02/04/2024] [Accepted: 07/01/2024] [Indexed: 08/10/2024]
Abstract
There is a strong relationship between metazoan body size and extinction risk. However, the size selectivity and underlying mechanisms in foraminifera, a common marine protozoa, remain controversial. Here, we found that foraminifera exhibit size-dependent extinction selectivity, favoring larger groups (>7.4 log10 cubic micrometer) over smaller ones. Foraminifera showed significant size selectivity in the Guadalupian-Lopingian, Permian-Triassic, and Cretaceous-Paleogene extinctions where the proportion of large genera exceeded 50%. Conversely, in extinctions where the proportion of large genera was <45%, foraminifera displayed no selectivity. As most of these extinctions coincided with oceanic anoxic events, we conducted simulations to assess the effects of ocean deoxygenation on foraminifera. Our results indicate that under suboxic conditions, oxygen fails to diffuse into the cell center of large foraminifera. Consequently, we propose a hypothesis to explain size distribution-related selectivity and Lilliput effect in animals relying on diffusion for oxygen during past and future ocean deoxygenation, i.e., oxygen diffusion distance in body.
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Affiliation(s)
- Yan Feng
- State Key Laboratory of Biogeology and Environmental Geology, School of Earth Sciences, China University of Geosciences, Wuhan 430074, China
| | - Haijun Song
- State Key Laboratory of Biogeology and Environmental Geology, School of Earth Sciences, China University of Geosciences, Wuhan 430074, China
| | - Hanchen Song
- State Key Laboratory of Biogeology and Environmental Geology, School of Earth Sciences, China University of Geosciences, Wuhan 430074, China
| | - Yuyang Wu
- State Key Laboratory of Biogeology and Environmental Geology, School of Earth Sciences, China University of Geosciences, Wuhan 430074, China
| | - Xing Li
- State Key Laboratory of Biogeology and Environmental Geology, School of Earth Sciences, China University of Geosciences, Wuhan 430074, China
| | - Li Tian
- State Key Laboratory of Biogeology and Environmental Geology, School of Earth Sciences, China University of Geosciences, Wuhan 430074, China
| | - Shuaishuai Dong
- Department of Marine Organism Taxonomy & Phylogeny, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China
- College of Marine Science and Fisheries, Jiangsu Ocean University, Lianyungang 222005, China
| | - Yanli Lei
- Department of Marine Organism Taxonomy & Phylogeny, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China
| | - Matthew E. Clapham
- Department of Earth and Planetary Sciences, University of California, Santa Cruz, Santa Cruz, CA 95064, USA
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Bubl M, Heinz P, Wanek W, Schagerl M, Hofmann T, Lintner M. Impact of heavy metals (Cu, Fe, Pb, Zn) on carbon and nitrogen uptake of the diatom-bearing benthic foraminifera Heterosteginadepressa. Heliyon 2024; 10:e27229. [PMID: 38496866 PMCID: PMC10944190 DOI: 10.1016/j.heliyon.2024.e27229] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2023] [Revised: 12/13/2023] [Accepted: 02/26/2024] [Indexed: 03/19/2024] Open
Abstract
Foraminifera are protists primarily living in benthic marine and estuarine environments. We studied uptake of inorganic carbon (C) and nitrogen (N) of the photosymbiont-bearing benthic coral reef foraminifera Heterostegina depressa in the presence of heavy metals. Incubation experiments were accomplished with artificial seawater enriched with copper, iron, lead and zinc at two different concentration levels (10 and 100 fold enriched in contrast to the usual culture medium). Additionally, isotopically labelled 13C-sodium bicarbonate and 15N-ammonium chloride were added to trace their assimilation over time (1 d, 3 d, 5 d, 7 d). Pulse-amplified modulated fluorescence measurements were performed to measure the potential impacts of heavy metals on chlorophyll fluorescence of the photosymbiont. Increased levels of copper (430.5 μg Cu/l) exhibited the greatest toxicity, while for low levels no effect on the overall metabolism of the foraminifera and the fluorescence activity of the photosymbiont could be detected. Iron (III) increased the symbiont activity, independent of concentration applied (44.5 and 513.3 μg Fe/l), which indicates Fe-limitation of the algal symbiont. Lead enrichment showed no detectable effect even at high concentration. Low concentrations of zinc (35.1 μg Zn/l) promoted the metabolism of the foraminifera, while high concentrations (598.4 μg Zn/l) were toxic. At low levels, two metals (Fe and Zn) promoted symbiont activity, at high levels, iron still boosted photosynthesis, but Zn and Cu had a negative impact on the obligatory photosynthetic symbionts.
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Affiliation(s)
- Mario Bubl
- Department of Palaeontology, University of Vienna, Vienna, Austria
| | - Petra Heinz
- Department of Palaeontology, University of Vienna, Vienna, Austria
| | - Wolfgang Wanek
- Department of Microbiology and Ecosystem Science, University of Vienna, Vienna, Austria
| | - Michael Schagerl
- Department of Functional and Evolutionary Ecology, University of Vienna, Vienna, Austria
| | - Thilo Hofmann
- Department of Environmental Geosciences, University of Vienna, Vienna, Austria
| | - Michael Lintner
- Department of Palaeontology, University of Vienna, Vienna, Austria
- ING PAN - Institute of Geological Sciences, Polish Academy of Sciences, Research Centre in Kraków, Poland
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Schweizer M, Jauffrais T, Choquel C, Méléder V, Quinchard S, Geslin E. Trophic strategies of intertidal foraminifera explored with single-cell microbiome metabarcoding and morphological methods: What is on the menu? Ecol Evol 2022; 12:e9437. [PMID: 36407902 PMCID: PMC9666909 DOI: 10.1002/ece3.9437] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2022] [Revised: 09/26/2022] [Accepted: 09/27/2022] [Indexed: 11/18/2022] Open
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.
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Affiliation(s)
- Magali Schweizer
- UMR 6112 LPG, Laboratoire de Planétologie et Géosciences, Univ Angers, Nantes Université, Le Mans UniversitéCNRSAngersFrance
| | - Thierry Jauffrais
- UMR 6112 LPG, Laboratoire de Planétologie et Géosciences, Univ Angers, Nantes Université, Le Mans UniversitéCNRSAngersFrance
- UMR 9220 ENTROPIE, Ifremer, IRD, Univ Nouvelle‐Calédonie, Univ La RéunionCNRSNoumeaNew Caledonia
| | - Constance Choquel
- UMR 6112 LPG, Laboratoire de Planétologie et Géosciences, Univ Angers, Nantes Université, Le Mans UniversitéCNRSAngersFrance
- Department of GeologyLund UniversityLundSweden
| | - Vona Méléder
- UR 2160, ISOMer, Institut des Substances et Organismes de la MerNantes UniversitéNantesFrance
| | - Sophie Quinchard
- UMR 6112 LPG, Laboratoire de Planétologie et Géosciences, Univ Angers, Nantes Université, Le Mans UniversitéCNRSAngersFrance
| | - Emmanuelle Geslin
- UMR 6112 LPG, Laboratoire de Planétologie et Géosciences, Univ Angers, Nantes Université, Le Mans UniversitéCNRSAngersFrance
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Woehle C, Roy AS, Glock N, Michels J, Wein T, Weissenbach J, Romero D, Hiebenthal C, Gorb SN, Schönfeld J, Dagan T. Denitrification in foraminifera has an ancient origin and is complemented by associated bacteria. Proc Natl Acad Sci U S A 2022; 119:e2200198119. [PMID: 35704763 PMCID: PMC9231491 DOI: 10.1073/pnas.2200198119] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2022] [Accepted: 05/05/2022] [Indexed: 11/18/2022] Open
Abstract
Benthic foraminifera are unicellular eukaryotes that inhabit sediments of aquatic environments. Several foraminifera of the order Rotaliida are known to store and use nitrate for denitrification, a unique energy metabolism among eukaryotes. The rotaliid Globobulimina spp. has been shown to encode an incomplete denitrification pathway of bacterial origin. However, the prevalence of denitrification genes in foraminifera remains unknown, and the missing denitrification pathway components are elusive. Analyzing transcriptomes and metagenomes of 10 foraminiferal species from the Peruvian oxygen minimum zone, we show that denitrification genes are highly conserved in foraminifera. We infer the last common ancestor of denitrifying foraminifera, which enables us to predict the ability to denitrify for additional foraminiferal species. Additionally, an examination of the foraminiferal microbiota reveals evidence for a stable interaction with Desulfobacteraceae, which harbor genes that complement the foraminiferal denitrification pathway. Our results provide evidence that foraminiferal denitrification is complemented by the foraminifera-associated microbiome. The interaction of foraminifera with their resident bacteria is at the basis of foraminiferal adaptation to anaerobic environments that manifested in ecological success in oxygen depleted habitats.
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Affiliation(s)
- Christian Woehle
- Institute of General Microbiology, Kiel University, Kiel 24118, Germany
| | | | - Nicolaas Glock
- GEOMAR Helmholtz Centre for Ocean Research Kiel, Kiel 24148, Germany
| | - Jan Michels
- Zoological Institute, Kiel University, Kiel 24118, Germany
| | - Tanita Wein
- Institute of General Microbiology, Kiel University, Kiel 24118, Germany
| | - Julia Weissenbach
- Institute of General Microbiology, Kiel University, Kiel 24118, Germany
| | - Dennis Romero
- Dirección General de Investigaciones Oceanográficas y Cambio Climático, Instituto del Mar del Perú, Callao 01, Peru 17
| | - Claas Hiebenthal
- GEOMAR Helmholtz Centre for Ocean Research Kiel, Kiel 24148, Germany
| | | | - Joachim Schönfeld
- GEOMAR Helmholtz Centre for Ocean Research Kiel, Kiel 24148, Germany
| | - Tal Dagan
- Institute of General Microbiology, Kiel University, Kiel 24118, Germany
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Kleptoplast distribution, photosynthetic efficiency and sequestration mechanisms in intertidal benthic foraminifera. THE ISME JOURNAL 2022; 16:822-832. [PMID: 34635793 PMCID: PMC8857221 DOI: 10.1038/s41396-021-01128-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/17/2021] [Revised: 09/19/2021] [Accepted: 09/22/2021] [Indexed: 11/19/2022]
Abstract
Foraminifera are ubiquitously distributed in marine habitats, playing a major role in marine sediment carbon sequestration and the nitrogen cycle. They exhibit a wide diversity of feeding and behavioural strategies (heterotrophy, autotrophy and mixotrophy), including species with the ability of sequestering intact functional chloroplasts from their microalgal food source (kleptoplastidy), resulting in a mixotrophic lifestyle. The mechanisms by which kleptoplasts are integrated and kept functional inside foraminiferal cytosol are poorly known. In our study, we investigated relationships between feeding strategies, kleptoplast spatial distribution and photosynthetic functionality in two shallow-water benthic foraminifera (Haynesina germanica and Elphidium williamsoni), both species feeding on benthic diatoms. We used a combination of observations of foraminiferal feeding behaviour, test morphology, cytological TEM-based observations and HPLC pigment analysis, with non-destructive, single-cell level imaging of kleptoplast spatial distribution and PSII quantum efficiency. The two species showed different feeding strategies, with H. germanica removing diatom content at the foraminifer's apertural region and E. williamsoni on the dorsal site. All E. williamsoni parameters showed that this species has higher autotrophic capacity albeit both feeding on benthic diatoms. This might represent two different stages in the evolutionary process of establishing a permanent symbiotic relationship, or may reflect different trophic strategies.
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Svetashev VI. Investigation of Deep-Sea Ecosystems Using Marker Fatty Acids: Sources of Essential Polyunsaturated Fatty Acids in Abyssal Megafauna. Mar Drugs 2021; 20:md20010017. [PMID: 35049873 PMCID: PMC8779288 DOI: 10.3390/md20010017] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Revised: 12/17/2021] [Accepted: 12/18/2021] [Indexed: 11/16/2022] Open
Abstract
Abyssal seafloor ecosystems cover more than 50% of the Earth's surface. Being formed by mainly heterotrophic organisms, they depend on the flux of particulate organic matter (POM) photosynthetically produced in the surface layer of the ocean. As dead phytoplankton sinks from the euphotic to the abyssal zone, the trophic value of POM and the concentration of essential polyunsaturated fatty acids (PUFA) decrease. This results in pronounced food periodicity and limitations for bottom dwellers. Deep-sea invertebrate seston eaters and surface deposit feeders consume the sinking POM. Other invertebrates utilize different food items that have undergone a trophic upgrade, with PUFA synthesized from saturated and monounsaturated FA. Foraminifera and nematodes can synthesize arachidonic acid (AA), eicosapentaenoic acid (EPA), while some barophylic bacteria produce EPA and/or docosahexaenoic acid. FA analysis of deep-sea invertebrates has shown high levels of PUFA including, in particular, arachidonic acid, bacterial FA, and a vast number of new and uncommon fatty acids such as 21:4(n-7), 22:4(n-8), 23:4(n-9), and 22:5(n-5) characteristic of foraminifera. We suppose that bacteria growing on detritus having a low trophic value provide the first trophic upgrading of organic matter for foraminifera and nematodes. In turn, these metazoans perform the second-stage upgrading for megafauna invertebrates. Deep-sea megafauna, including major members of Echinodermata, Mollusca, and Polychaeta display FA markers characteristic of bacteria, foraminifera, and nematodes and reveal new markers in the food chain.
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Affiliation(s)
- Vasily I Svetashev
- A.V. Zhirmunsky National Scientific Center of Marine Biology, Far Eastern Branch, Russian Academy of Sciences, 17 Palchevskogo Str., Vladivostok 690041, Russia
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7
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Szymańska N, Łącka M, Koziorowska-Makuch K, Kuliński K, Pawłowska J, Kujawa A, Telesiński MM, Zajączkowski M. Foraminifera-derived carbon contribution to sedimentary inorganic carbon pool: A case study from three Norwegian fjords. GEOBIOLOGY 2021; 19:631-641. [PMID: 34143930 DOI: 10.1111/gbi.12460] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/10/2021] [Accepted: 05/22/2021] [Indexed: 06/12/2023]
Abstract
Norwegian fjords have been recently recognized as hot spots for carbon burial due to the large amounts of terrestrial organic matter delivered to fjord sediments, as well as the high sediment accumulation rates. Here, we present the first data on the contribution of benthic foraminiferal inorganic carbon to the sediments of three Norwegian fjords. Our study shows that calcareous foraminifera, which are among the most abundant calcifying organisms in the modern global oceans, can constitute between 15% and 33% of inorganic carbon accumulated in the sediments of the two studied southern Norwegian fjords (Raunefjorden and Hjeltefjorden). In a northern Norwegian fjord (Balsfjorden), the contribution of calcareous foraminifera to the inorganic carbon pool is smaller (<1%) than the one observed in southern fjords. We also found that the amount of foraminifera-derived carbon is primarily dependent on the species composition of the foraminifera community. Large calcareous foraminifera species, despite a lower number of individuals, constitute, on average, 13%-29% of the inorganic carbon in the two southern Norwegian fjords, while the contribution of small, highly abundant species does not exceed 4% of the inorganic carbon pools in the sediments. Calcareous foraminifera species that are indicative of dysoxic conditions have been found to have low inorganic carbon contents per specimen compared to other analysed similar-sized calcareous foraminifera species. This relationship most likely exists due to the thin test walls of these foraminifera species, which may facilitate gas exchange. The results of our case study suggest that the climate-driven formation of near-bottom low-oxygen zones may lead to the dominance of foraminifera associated with dysoxic conditions and, in consequence, to the decrease of foraminifera-derived inorganic carbon. However, to properly analyse the contribution of carbon from thin-walled foraminifera to the sedimentary carbon pool, further studies analysing a broader range of these species is needed.
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Affiliation(s)
| | - Magdalena Łącka
- Institute of Oceanology, Polish Academy of Sciences, Sopot, Poland
| | | | - Karol Kuliński
- Institute of Oceanology, Polish Academy of Sciences, Sopot, Poland
| | - Joanna Pawłowska
- Institute of Oceanology, Polish Academy of Sciences, Sopot, Poland
| | - Agnieszka Kujawa
- Institute of Oceanology, Polish Academy of Sciences, Sopot, Poland
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Salonen IS, Chronopoulou PM, Nomaki H, Langlet D, Tsuchiya M, Koho KA. 16S rRNA Gene Metabarcoding Indicates Species-Characteristic Microbiomes in Deep-Sea Benthic Foraminifera. Front Microbiol 2021; 12:694406. [PMID: 34385987 PMCID: PMC8353385 DOI: 10.3389/fmicb.2021.694406] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2021] [Accepted: 07/06/2021] [Indexed: 11/13/2022] Open
Abstract
Foraminifera are unicellular eukaryotes that are an integral part of benthic fauna in many marine ecosystems, including the deep sea, with direct impacts on benthic biogeochemical cycles. In these systems, different foraminiferal species are known to have a distinct vertical distribution, i.e., microhabitat preference, which is tightly linked to the physico-chemical zonation of the sediment. Hence, foraminifera are well-adapted to thrive in various conditions, even under anoxia. However, despite the ecological and biogeochemical significance of foraminifera, their ecology remains poorly understood. This is especially true in terms of the composition and diversity of their microbiome, although foraminifera are known to harbor diverse endobionts, which may have a significant meaning to each species' survival strategy. In this study, we used 16S rRNA gene metabarcoding to investigate the microbiomes of five different deep-sea benthic foraminiferal species representing differing microhabitat preferences. The microbiomes of these species were compared intra- and inter-specifically, as well as with the surrounding sediment bacterial community. Our analysis indicated that each species was characterized with a distinct, statistically different microbiome that also differed from the surrounding sediment community in terms of diversity and dominant bacterial groups. We were also able to distinguish specific bacterial groups that seemed to be strongly associated with particular foraminiferal species, such as the family Marinilabiliaceae for Chilostomella ovoidea and the family Hyphomicrobiaceae for Bulimina subornata and Bulimina striata. The presence of bacterial groups that are tightly associated to a certain foraminiferal species implies that there may exist unique, potentially symbiotic relationships between foraminifera and bacteria that have been previously overlooked. Furthermore, the foraminifera contained chloroplast reads originating from different sources, likely reflecting trophic preferences and ecological characteristics of the different species. This study demonstrates the potential of 16S rRNA gene metabarcoding in resolving the microbiome composition and diversity of eukaryotic unicellular organisms, providing unique in situ insights into enigmatic deep-sea ecosystems.
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Affiliation(s)
- Iines S Salonen
- Ecosystems and Environment Research Program, University of Helsinki, Helsinki, Finland.,SUGAR, X-star, Japan Agency of Marine-Earth Science and Technology (JAMSTEC), Yokosuka, Japan
| | | | - Hidetaka Nomaki
- SUGAR, X-star, Japan Agency of Marine-Earth Science and Technology (JAMSTEC), Yokosuka, Japan
| | - Dewi Langlet
- SUGAR, X-star, Japan Agency of Marine-Earth Science and Technology (JAMSTEC), Yokosuka, Japan.,UMR 8187 - LOG - Laboratoire d'Océanologie et de Géosciences, Université de Lille - CNRS, Université du Littoral Côte d'Opale, Station Marine de Wimereux, Lille, France.,Evolution, Cell Biology, and Symbiosis Unit, Okinawa Institute of Science and Technology, Okinawa, Japan
| | - Masashi Tsuchiya
- Research Institute for Global Change (RIGC), Japan Agency of Marine-Earth Science and Technology (JAMSTEC), Yokosuka, Japan
| | - Karoliina A Koho
- Ecosystems and Environment Research Program, University of Helsinki, Helsinki, Finland
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Nomaki H, Chen C, Oda K, Tsuchiya M, Tame A, Uematsu K, Isobe N. Abundant Chitinous Structures in Chilostomella (Foraminifera, Rhizaria) and Their Potential Functions. J Eukaryot Microbiol 2021; 68:e12828. [PMID: 33128276 PMCID: PMC7894498 DOI: 10.1111/jeu.12828] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2020] [Revised: 08/28/2020] [Accepted: 10/20/2020] [Indexed: 12/01/2022]
Abstract
Benthic foraminifera, members of Rhizaria, inhabit a broad range of marine environments and are particularly common in hypoxic sediments. The biology of benthic foraminifera is key to understanding benthic ecosystems and relevant biogeochemical cycles, especially in hypoxic environments. Chilostomella is a foraminiferal genus commonly found in hypoxic deep-sea sediments and has poorly understood ecological characteristics. For example, the carbon isotopic compositions of their lipids are substantially different from other co-occurring genera, probably reflecting unique features of its metabolism. Here, we investigated the cytoplasmic and ultrastructural features of Chilostomella ovoidea from bathyal sediments of Sagami Bay, Japan, based on serial semi-thin sections examined using an optical microscope followed by a three-dimensional reconstruction, combined with TEM observations of ultra-thin sections. Observations by TEM revealed the presence of abundant electron-dense structures dividing the cytoplasm. Based on histochemical staining, these structures are shown to be composed of chitin. Our 3D reconstruction revealed chitinous structures in the final seven chambers. These exhibited a plate-like morphology in the final chambers but became rolled up in earlier chambers (toward the proloculus). These chitinous, plate-like structures may function to partition the cytoplasm in a chamber to increase the surface/volume ratio and/or act as a reactive site for some metabolic functions.
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Affiliation(s)
- Hidetaka Nomaki
- SUGAR, X‐starJapan Agency for Marine‐Earth Science and Technology (JAMSTEC)2‐15 Natsushima‐choYokosukaKanagawa237‐0061Japan
| | - Chong Chen
- SUGAR, X‐starJapan Agency for Marine‐Earth Science and Technology (JAMSTEC)2‐15 Natsushima‐choYokosukaKanagawa237‐0061Japan
| | - Kaya Oda
- SUGAR, X‐starJapan Agency for Marine‐Earth Science and Technology (JAMSTEC)2‐15 Natsushima‐choYokosukaKanagawa237‐0061Japan
| | - Masashi Tsuchiya
- Research Institute for Global Change (RIGC)Japan Agency for Marine‐Earth Science and Technology (JAMSTEC)YokosukaKanagawa
237‐0061Japan
| | - Akihiro Tame
- Marine Works Japan Ltd.3‐54‐1 Oppamahigashi‐choYokosukaKanagawa237‐0063Japan
| | - Katsuyuki Uematsu
- Marine Works Japan Ltd.3‐54‐1 Oppamahigashi‐choYokosukaKanagawa237‐0063Japan
| | - Noriyuki Isobe
- Research Institute for Marine Resources Utilization (MRU)Japan Agency for Marine‐Earth Science and Technology (JAMSTEC)YokosukaKanagawa237‐0061Japan
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10
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Bird C, LeKieffre C, Jauffrais T, Meibom A, Geslin E, Filipsson HL, Maire O, Russell AD, Fehrenbacher JS. Heterotrophic Foraminifera Capable of Inorganic Nitrogen Assimilation. Front Microbiol 2020; 11:604979. [PMID: 33343548 PMCID: PMC7744380 DOI: 10.3389/fmicb.2020.604979] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2020] [Accepted: 11/11/2020] [Indexed: 11/17/2022] Open
Abstract
Nitrogen availability often limits biological productivity in marine systems, where inorganic nitrogen, such as ammonium is assimilated into the food web by bacteria and photoautotrophic eukaryotes. Recently, ammonium assimilation was observed in kleptoplast-containing protists of the phylum foraminifera, possibly via the glutamine synthetase/glutamate synthase (GS/GOGAT) assimilation pathway imported with the kleptoplasts. However, it is not known if the ubiquitous and diverse heterotrophic protists have an innate ability for ammonium assimilation. Using stable isotope incubations (15N-ammonium and 13C-bicarbonate) and combining transmission electron microscopy (TEM) with quantitative nanoscale secondary ion mass spectrometry (NanoSIMS) imaging, we investigated the uptake and assimilation of dissolved inorganic ammonium by two heterotrophic foraminifera; a non-kleptoplastic benthic species, Ammonia sp., and a planktonic species, Globigerina bulloides. These species are heterotrophic and not capable of photosynthesis. Accordingly, they did not assimilate 13C-bicarbonate. However, both species assimilated dissolved 15N-ammonium and incorporated it into organelles of direct importance for ontogenetic growth and development of the cell. These observations demonstrate that at least some heterotrophic protists have an innate cellular mechanism for inorganic ammonium assimilation, highlighting a newly discovered pathway for dissolved inorganic nitrogen (DIN) assimilation within the marine microbial loop.
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Affiliation(s)
- Clare Bird
- Biological and Environmental Sciences, Faculty of Natural Sciences, University of Stirling, Stirling, United Kingdom.,School of GeoSciences, Grant Institute, University of Edinburgh, Edinburgh, United Kingdom
| | - Charlotte LeKieffre
- Laboratory for Biological Geochemistry, School of Architecture, Civil and Environmental Engineering (ENAC), Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland.,UMR CNRS 6112 LPG, Bio-Indicateurs Actuels et Fossiles, Université d'Angers, Angers, France
| | - Thierry Jauffrais
- Ifremer, IRD, Univ Nouvelle-Calédonie, Univ La Réunion, CNRS, UMR 9220 ENTROPIE, Nouméa, New Caledonia
| | - Anders Meibom
- Laboratory for Biological Geochemistry, School of Architecture, Civil and Environmental Engineering (ENAC), Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland.,Centre for Advanced Surface Analysis, Institute of Earth Sciences, University of Lausanne, Lausanne, Switzerland
| | - Emmanuelle Geslin
- UMR CNRS 6112 LPG, Bio-Indicateurs Actuels et Fossiles, Université d'Angers, Angers, France
| | | | - Olivier Maire
- Université de Bordeaux, EPOC, UMR 5805, Talence, France.,CNRS, EPOC, UMR 5805, Talence, France
| | - Ann D Russell
- Department of Earth and Planetary Sciences, University of California, Davis, Davis, CA, United States
| | - Jennifer S Fehrenbacher
- College of Earth, Ocean, and Atmospheric Sciences, Oregon State University, Corvallis, OR, United States
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11
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Anaerobic metabolism of Foraminifera thriving below the seafloor. ISME JOURNAL 2020; 14:2580-2594. [PMID: 32641728 PMCID: PMC7490399 DOI: 10.1038/s41396-020-0708-1] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/26/2020] [Revised: 06/09/2020] [Accepted: 06/23/2020] [Indexed: 02/06/2023]
Abstract
Foraminifera are single-celled eukaryotes (protists) of large ecological importance, as well as environmental and paleoenvironmental indicators and biostratigraphic tools. In addition, they are capable of surviving in anoxic marine environments where they represent a major component of the benthic community. However, the cellular adaptations of Foraminifera to the anoxic environment remain poorly constrained. We sampled an oxic-anoxic transition zone in marine sediments from the Namibian shelf, where the genera Bolivina and Stainforthia dominated the Foraminifera community, and use metatranscriptomics to characterize Foraminifera metabolism across the different geochemical conditions. Relative Foraminifera gene expression in anoxic sediment increased an order of magnitude, which was confirmed in a 10-day incubation experiment where the development of anoxia coincided with a 20–40-fold increase in the relative abundance of Foraminifera protein encoding transcripts, attributed primarily to those involved in protein synthesis, intracellular protein trafficking, and modification of the cytoskeleton. This indicated that many Foraminifera were not only surviving but thriving, under the anoxic conditions. The anaerobic energy metabolism of these active Foraminifera was characterized by fermentation of sugars and amino acids, fumarate reduction, and potentially dissimilatory nitrate reduction. Moreover, the gene expression data indicate that under anoxia Foraminifera use the phosphogen creatine phosphate as an ATP store, allowing reserves of high-energy phosphate pool to be maintained for sudden demands of increased energy during anaerobic metabolism. This was co-expressed alongside genes involved in phagocytosis and clathrin-mediated endocytosis (CME). Foraminifera may use CME to utilize dissolved organic matter as a carbon and energy source, in addition to ingestion of prey cells via phagocytosis. These anaerobic metabolic mechanisms help to explain the ecological success of Foraminifera documented in the fossil record since the Cambrian period more than 500 million years ago.
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12
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LeKieffre C, Spero HJ, Fehrenbacher JS, Russell AD, Ren H, Geslin E, Meibom A. Ammonium is the preferred source of nitrogen for planktonic foraminifer and their dinoflagellate symbionts. Proc Biol Sci 2020; 287:20200620. [PMID: 32546098 PMCID: PMC7329048 DOI: 10.1098/rspb.2020.0620] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
The symbiotic planktonic foraminifera Orbulina universa inhabits open ocean oligotrophic ecosystems where dissolved nutrients are scarce and often limit biological productivity. It has previously been proposed that O. universa meets its nitrogen (N) requirements by preying on zooplankton, and that its symbiotic dinoflagellates recycle metabolic ‘waste ammonium’ for their N pool. However, these conclusions were derived from bulk 15N-enrichment experiments and model calculations, and our understanding of N assimilation and exchange between the foraminifer host cell and its symbiotic dinoflagellates remains poorly constrained. Here, we present data from pulse-chase experiments with 13C-enriched inorganic carbon, 15N-nitrate, and 15N-ammonium, as well as a 13C- and 15N- enriched heterotrophic food source, followed by TEM (transmission electron microscopy) coupled to NanoSIMS (nanoscale secondary ion mass spectrometry) isotopic imaging to visualize and quantify C and N assimilation and translocation in the symbiotic system. High levels of 15N-labelling were observed in the dinoflagellates and in foraminiferal organelles and cytoplasm after incubation with 15N-ammonium, indicating efficient ammonium assimilation. Only weak 15N-assimilation was observed after incubation with 15N-nitrate. Feeding foraminifers with 13C- and 15N-labelled food resulted in dinoflagellates that were labelled with 15N, thereby confirming the transfer of 15N-compounds from the digestive vacuoles of the foraminifer to the symbiotic dinoflagellates, likely through recycling of ammonium. These observations are important for N isotope-based palaeoceanographic reconstructions, as they show that δ15N values recorded in the organic matrix in symbiotic species likely reflect ammonium recycling rather than alternative N sources, such as nitrates.
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Affiliation(s)
- Charlotte LeKieffre
- Laboratory for Biological Geochemistry, School of Architecture, Civil and Environmental Engineering (ENAC), Ecole Polytechnique Fédérale de Lausanne (EPFL), Switzerland.,UMR CNRS 6112 - LPG-BIAF, Université d'Angers, 49045 Angers Cedex, France
| | - Howard J Spero
- Department of Earth and Planetary Sciences, University of California Davis, Davis, CA 95616, USA
| | - Jennifer S Fehrenbacher
- College of Earth, Ocean, and Atmospheric Sciences, Oregon State University, Corvallis, OR 97331, USA
| | - Ann D Russell
- Department of Earth and Planetary Sciences, University of California Davis, Davis, CA 95616, USA
| | - Haojia Ren
- Department of Geosciences, National Taiwan University, Taipei, Taiwan
| | - Emmanuelle Geslin
- UMR CNRS 6112 - LPG-BIAF, Université d'Angers, 49045 Angers Cedex, France
| | - Anders Meibom
- Laboratory for Biological Geochemistry, School of Architecture, Civil and Environmental Engineering (ENAC), Ecole Polytechnique Fédérale de Lausanne (EPFL), Switzerland.,Center for Advanced Surface Analysis, Institute of Earth Sciences, University of Lausanne, Switzerland
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13
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Jauffrais T, LeKieffre C, Schweizer M, Jesus B, Metzger E, Geslin E. Response of a kleptoplastidic foraminifer to heterotrophic starvation: photosynthesis and lipid droplet biogenesis. FEMS Microbiol Ecol 2020; 95:5427914. [PMID: 30947330 DOI: 10.1093/femsec/fiz046] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2019] [Accepted: 04/02/2019] [Indexed: 01/21/2023] Open
Abstract
The aim of this work is to document the complex nutritional strategy developed by kleptoplastic intertidal foraminifera. We study the mixotrophic ability of a common intertidal foraminifer, Elphidium williamsoni, by (i) investigating the phylogenetic identity of the foraminiferal kleptoplasts, (ii) following their oxygenic photosynthetic capacity and (iii) observing the modification in cellular ultrastructural features in response to photoautotrophic conditions. This was achieved by coupling molecular phylogenetic analyses and TEM observations with non-destructive measurements of kleptoplast O2 production over a 15-day experimental study. Results show that the studied E. williamsoni actively selected kleptoplasts mainly from pennate diatoms and had the ability to produce oxygen, up to 13.4 nmol O2 cell-1 d-1, from low to relatively high irradiance over at least 15 days. Ultrastructural features and photophysiological data showed significant differences over time, the number of lipid droplets, residual bodies and the dark respiration increased; whereas, the number of kleptoplasts decreased accompanied by a minor decrease of the photosynthetic rate. These observations suggest that in E. williamsoni kleptoplasts might provide extra carbon storage through lipid droplets synthesis and highlight the complexity of E. williamsoni feeding strategy and the necessity of further dedicated studies regarding mechanisms developed by kleptoplastidic foraminifera for carbon partitioning and storage.
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Affiliation(s)
- Thierry Jauffrais
- UMR CNRS 6112 LPG-BIAF, Bio-Indicateurs Actuels et Fossiles, Université d'Angers, 2 Boulevard Lavoisier, 49045 Angers CEDEX 1, France.,Ifremer, RBE/LEAD, 101 Promenade Roger Laroque, 98897 Nouméa, New Caledonia, France
| | - Charlotte LeKieffre
- UMR CNRS 6112 LPG-BIAF, Bio-Indicateurs Actuels et Fossiles, Université d'Angers, 2 Boulevard Lavoisier, 49045 Angers CEDEX 1, France
| | - Magali Schweizer
- UMR CNRS 6112 LPG-BIAF, Bio-Indicateurs Actuels et Fossiles, Université d'Angers, 2 Boulevard Lavoisier, 49045 Angers CEDEX 1, France
| | - Bruno Jesus
- EA2160, Laboratoir Mer Molécules Santé, 2 rue de la Houssinière, Université de Nantes, 4433 Nantes Cedex 1, France
| | - Edouard Metzger
- UMR CNRS 6112 LPG-BIAF, Bio-Indicateurs Actuels et Fossiles, Université d'Angers, 2 Boulevard Lavoisier, 49045 Angers CEDEX 1, France
| | - Emmanuelle Geslin
- UMR CNRS 6112 LPG-BIAF, Bio-Indicateurs Actuels et Fossiles, Université d'Angers, 2 Boulevard Lavoisier, 49045 Angers CEDEX 1, France
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14
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The Puzzling Conservation and Diversification of Lipid Droplets from Bacteria to Eukaryotes. Results Probl Cell Differ 2020; 69:281-334. [PMID: 33263877 DOI: 10.1007/978-3-030-51849-3_11] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Membrane compartments are amongst the most fascinating markers of cell evolution from prokaryotes to eukaryotes, some being conserved and the others having emerged via a series of primary and secondary endosymbiosis events. Membrane compartments comprise the system limiting cells (one or two membranes in bacteria, a unique plasma membrane in eukaryotes) and a variety of internal vesicular, subspherical, tubular, or reticulated organelles. In eukaryotes, the internal membranes comprise on the one hand the general endomembrane system, a dynamic network including organelles like the endoplasmic reticulum, the Golgi apparatus, the nuclear envelope, etc. and also the plasma membrane, which are linked via direct lateral connectivity (e.g. between the endoplasmic reticulum and the nuclear outer envelope membrane) or indirectly via vesicular trafficking. On the other hand, semi-autonomous organelles, i.e. mitochondria and chloroplasts, are disconnected from the endomembrane system and request vertical transmission following cell division. Membranes are organized as lipid bilayers in which proteins are embedded. The budding of some of these membranes, leading to the formation of the so-called lipid droplets (LDs) loaded with hydrophobic molecules, most notably triacylglycerol, is conserved in all clades. The evolution of eukaryotes is marked by the acquisition of mitochondria and simple plastids from Gram-positive bacteria by primary endosymbiosis events and the emergence of extremely complex plastids, collectively called secondary plastids, bounded by three to four membranes, following multiple and independent secondary endosymbiosis events. There is currently no consensus view of the evolution of LDs in the Tree of Life. Some features are conserved; others show a striking level of diversification. Here, we summarize the current knowledge on the architecture, dynamics, and multitude of functions of the lipid droplets in prokaryotes and in eukaryotes deriving from primary and secondary endosymbiosis events.
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15
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Enrichment of intracellular sulphur cycle -associated bacteria in intertidal benthic foraminifera revealed by 16S and aprA gene analysis. Sci Rep 2019; 9:11692. [PMID: 31406214 PMCID: PMC6690927 DOI: 10.1038/s41598-019-48166-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2019] [Accepted: 07/30/2019] [Indexed: 12/21/2022] Open
Abstract
Benthic foraminifera are known to play an important role in marine carbon and nitrogen cycles. Here, we report an enrichment of sulphur cycle -associated bacteria inside intertidal benthic foraminifera (Ammonia sp. (T6), Haynesina sp. (S16) and Elphidium sp. (S5)), using a metabarcoding approach targeting the 16S rRNA and aprA -genes. The most abundant intracellular bacterial groups included the genus Sulfurovum and the order Desulfobacterales. The bacterial 16S OTUs are likely to originate from the sediment bacterial communities, as the taxa found inside the foraminifera were also present in the sediment. The fact that 16S rRNA and aprA -gene derived intracellular bacterial OTUs were species-specific and significantly different from the ambient sediment community implies that bacterivory is an unlikely scenario, as benthic foraminifera are known to digest bacteria only randomly. Furthermore, these foraminiferal species are known to prefer other food sources than bacteria. The detection of sulphur-cycle related bacterial genes in this study suggests a putative role for these bacteria in the metabolism of the foraminiferal host. Future investigation into environmental conditions under which transcription of S-cycle genes are activated would enable assessment of their role and the potential foraminiferal/endobiont contribution to the sulphur-cycle.
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16
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Richirt J, Champmartin S, Schweizer M, Mouret A, Petersen J, Ambari A, Jorissen FJ. Scaling laws explain foraminiferal pore patterns. Sci Rep 2019; 9:9149. [PMID: 31235827 PMCID: PMC6591427 DOI: 10.1038/s41598-019-45617-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2019] [Accepted: 05/30/2019] [Indexed: 11/09/2022] Open
Abstract
Due to climate warming and increased anthropogenic impact, a decrease of ocean water oxygenation is expected in the near future, with major consequences for marine life. In this context, it is essential to develop reliable tools to assess past oxygen concentrations in the ocean, to better forecast these future changes. Recently, foraminiferal pore patterns have been proposed as a bottom water oxygenation proxy, but the parameters controlling foraminiferal pore patterns are still largely unknown. Here we use scaling laws to describe how both gas exchanges (metabolic needs) and mechanical constraints (shell robustness) control foraminiferal pore patterns. The derived mathematical model shows that only specific combinations of pore density and size are physically feasible. Maximum porosity, of about 30%, can only be obtained by simultaneously increasing pore size and decreasing pore density. A large empirical data set of pore data obtained for three pseudocryptic phylotypes of Ammonia, a common intertidal genus from the eastern Atlantic, strongly supports this conclusion. These new findings provide basic mechanistic understanding of the complex controls of foraminiferal pore patterns and give a solid starting point for the development of proxies of past oxygen concentrations based on these morphological features. Pore size and pore density are largely interdependent, and both have to be considered when describing pore patterns.
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Affiliation(s)
- Julien Richirt
- UMR 6112 LPG-BIAF Recent and Fossil Bio-Indicators, Angers University, 2 Bd Lavoisier, F-49045, Angers, France.
| | - Stéphane Champmartin
- LAMPA, Arts et Métiers ParisTech, 2 Bd du Ronceray, BP 93525, 49035, Angers, Cedex 01, France
| | - Magali Schweizer
- UMR 6112 LPG-BIAF Recent and Fossil Bio-Indicators, Angers University, 2 Bd Lavoisier, F-49045, Angers, France
| | - Aurélia Mouret
- UMR 6112 LPG-BIAF Recent and Fossil Bio-Indicators, Angers University, 2 Bd Lavoisier, F-49045, Angers, France
| | - Jassin Petersen
- Institute of Geology and Mineralogy, University of Cologne, Zülpicher Str. 49a, 50674, Cologne, Germany
| | - Abdelhak Ambari
- LAMPA, Arts et Métiers ParisTech, 2 Bd du Ronceray, BP 93525, 49035, Angers, Cedex 01, France
| | - Frans J Jorissen
- UMR 6112 LPG-BIAF Recent and Fossil Bio-Indicators, Angers University, 2 Bd Lavoisier, F-49045, Angers, France
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17
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Chronopoulou PM, Salonen I, Bird C, Reichart GJ, Koho KA. Metabarcoding Insights Into the Trophic Behavior and Identity of Intertidal Benthic Foraminifera. Front Microbiol 2019; 10:1169. [PMID: 31191490 PMCID: PMC6547873 DOI: 10.3389/fmicb.2019.01169] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2018] [Accepted: 05/07/2019] [Indexed: 12/29/2022] Open
Abstract
Foraminifera are ubiquitous marine protists with an important role in the benthic carbon cycle. However, morphological observations often fail to resolve their exact taxonomic placement and there is a lack of field studies on their particular trophic preferences. Here, we propose the application of metabarcoding as a tool for the elucidation of the in situ feeding behavior of benthic foraminifera, while also allowing the correct taxonomic assignment of the feeder, using the V9 region of the 18S (small subunit; SSU) rRNA gene. Living foraminiferal specimens were collected from two intertidal mudflats of the Wadden Sea and DNA was extracted from foraminiferal individuals and from the surrounding sediments. Molecular analysis allowed us to confirm that our foraminiferal specimens belong to three genetic types: Ammonia sp. T6, Elphidium sp. S5 and Haynesina sp. S16. Foraminiferal intracellular eukaryote communities reflected to an extent those of the surrounding sediments but at different relative abundances. Unlike sediment eukaryote communities, which were largely determined by the sampling site, foraminiferal intracellular eukaryote communities were driven by foraminiferal species, followed by sediment depth. Our data suggests that Ammonia sp. T6 can predate on metazoan classes, whereas Elphidium sp. S5 and Haynesina sp. S16 are more likely to ingest diatoms. These observations, alongside the use of metabarcoding in similar ecological studies, significantly contribute to our overall understanding of the ecological roles of these protists in intertidal benthic environments and their position and function in the benthic food webs.
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Affiliation(s)
- Panagiota-Myrsini Chronopoulou
- Aquatic Biogeochemistry Research Unit, Ecosystems and Environment Research Programme, Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki, Finland
| | - Iines Salonen
- Aquatic Biogeochemistry Research Unit, Ecosystems and Environment Research Programme, Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki, Finland
| | - Clare Bird
- Biological and Environmental Sciences, University of Stirling, Stirling, United Kingdom
| | - Gert-Jan Reichart
- Department of Ocean Systems, NIOZ-Royal Netherlands Institute for Sea Research and Utrecht University, Den Burg, Netherlands
| | - Karoliina A Koho
- Aquatic Biogeochemistry Research Unit, Ecosystems and Environment Research Programme, Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki, Finland
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18
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Jauffrais T, LeKieffre C, Schweizer M, Geslin E, Metzger E, Bernhard JM, Jesus B, Filipsson HL, Maire O, Meibom A. Kleptoplastidic benthic foraminifera from aphotic habitats: insights into assimilation of inorganic C, N and S studied with sub-cellular resolution. Environ Microbiol 2018; 21:125-141. [PMID: 30277305 DOI: 10.1111/1462-2920.14433] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2018] [Revised: 08/31/2018] [Accepted: 09/24/2018] [Indexed: 10/28/2022]
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 13 C-bicarbonate, 15 N-ammonium and 34 S-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 13 C 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 15 N-ammonium and 34 S-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.
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Affiliation(s)
- Thierry Jauffrais
- UMR CNRS 6112 LPG-BIAF, Université d'Angers, 2 Boulevard Lavoisier, 49045, Angers Cedex 1, France.,Ifremer, RBE/LEAD, 101 Promenade Roger Laroque, 98897, Nouméa, New Caledonia
| | - Charlotte LeKieffre
- UMR CNRS 6112 LPG-BIAF, Université d'Angers, 2 Boulevard Lavoisier, 49045, Angers Cedex 1, France.,Laboratory for Biological Geochemistry, School of Architecture, Civil and Environmental Engineering (ENAC), Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015, Lausanne, Switzerland
| | - Magali Schweizer
- UMR CNRS 6112 LPG-BIAF, Université d'Angers, 2 Boulevard Lavoisier, 49045, Angers Cedex 1, France
| | - Emmanuelle Geslin
- UMR CNRS 6112 LPG-BIAF, Université d'Angers, 2 Boulevard Lavoisier, 49045, Angers Cedex 1, France
| | - Edouard Metzger
- UMR CNRS 6112 LPG-BIAF, Université d'Angers, 2 Boulevard Lavoisier, 49045, Angers Cedex 1, France
| | - Joan M Bernhard
- Woods Hole Oceanographic Institution, Geology & Geophysics Department, Woods Hole, MA, USA
| | - Bruno Jesus
- EA2160, Laboratoire Mer Molécules Santé, Université de Nantes, Nantes, France.,BioISI - Biosystems & Integrative Sciences Institute, Campo Grande University of Lisboa, Faculty of Sciences, Lisbon, Portugal
| | - Helena L Filipsson
- Department of Geology, Lund University, Sölvegatan 12, 223 62, Lund, Sweden
| | - Olivier Maire
- Univ. Bordeaux, EPOC, UMR 5805, 33400, Talence, France.,CNRS, EPOC, UMR 5805, 33400, Talence, France
| | - Anders Meibom
- Laboratory for Biological Geochemistry, School of Architecture, Civil and Environmental Engineering (ENAC), Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015, Lausanne, Switzerland.,Center for Advanced Surface Analysis, Institute of Earth Sciences, University of Lausanne, 1015, Lausanne, Switzerland
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19
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Inorganic carbon and nitrogen assimilation in cellular compartments of a benthic kleptoplastic foraminifer. Sci Rep 2018; 8:10140. [PMID: 29973634 PMCID: PMC6031614 DOI: 10.1038/s41598-018-28455-1] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2018] [Accepted: 06/20/2018] [Indexed: 11/08/2022] Open
Abstract
Haynesina germanica, an ubiquitous benthic foraminifer in intertidal mudflats, has the remarkable ability to isolate, sequester, and use chloroplasts from microalgae. The photosynthetic functionality of these kleptoplasts has been demonstrated by measuring photosystem II quantum efficiency and O2 production rates, but the precise role of the kleptoplasts in foraminiferal metabolism is poorly understood. Thus, the mechanism and dynamics of C and N assimilation and translocation from the kleptoplasts to the foraminiferal host requires study. The objective of this study was to investigate, using correlated TEM and NanoSIMS imaging, the assimilation of inorganic C and N (here ammonium, NH4+) in individuals of a kleptoplastic benthic foraminiferal species. H. germanica specimens were incubated for 20 h in artificial seawater enriched with H13CO3- and 15NH4+ during a light/dark cycle. All specimens (n = 12) incorporated 13C into their endoplasm stored primarily in the form of lipid droplets. A control incubation in darkness resulted in no 13C-uptake, strongly suggesting that photosynthesis is the process dominating inorganic C assimilation. Ammonium assimilation was observed both with and without light, with diffuse 15N-enrichment throughout the cytoplasm and distinct 15N-hotspots in fibrillar vesicles, electron-opaque bodies, tubulin paracrystals, bacterial associates, and, rarely and at moderate levels, in kleptoplasts. The latter observation might indicate that the kleptoplasts are involved in N assimilation. However, the higher N assimilation observed in the foraminiferal endoplasm incubated without light suggests that another cytoplasmic pathway is dominant, at least in darkness. This study clearly shows the advantage provided by the kleptoplasts as an additional source of carbon and provides observations of ammonium uptake by the foraminiferal cell.
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20
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Wukovits J, Bukenberger P, Enge AJ, Gerg M, Wanek W, Watzka M, Heinz P. Food supply and size class depending variations in phytodetritus intake in the benthic foraminifer Ammonia tepida. Biol Open 2018. [PMID: 29540430 PMCID: PMC5936058 DOI: 10.1242/bio.030056] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Ammonia tepida is a common and abundant benthic foraminifer in intertidal mudflats. Benthic foraminifera are primary consumers and detritivores and act as key players in sediment nutrient fluxes. In this study, laboratory feeding experiments using isotope-labeled phytodetritus were carried out with A. tepida collected at the German Wadden Sea, to investigate the response of A. tepida to varying food supply. Feeding mode (single pulse, constant feeding; different incubation temperatures) caused strong variations in cytoplasmic carbon and nitrogen cycling, suggesting generalistic adaptations to variations in food availability. To study the influence of intraspecific size to foraminiferal carbon and nitrogen cycling, three size fractions (125-250 µm, 250-355 µm, >355 µm) of A. tepida specimens were separated. Small individuals showed higher weight specific intake for phytodetritus, especially for phytodetrital nitrogen, highlighting that size distribution within foraminiferal populations is relevant to interpret foraminiferal carbon and nitrogen cycling. These results were used to extrapolate the data to natural populations of living A. tepida in sediment cores, demonstrating the impact of high abundances of small individuals on phytodetritus processing and nutrient cycling. It is estimated that at high abundances of individuals in the 125-250 µm size fraction, Ammonia populations can account for more than 11% of phytodetritus processing in intertidal benthic communities.
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Affiliation(s)
- Julia Wukovits
- Department of Palaeontology, University of Vienna, Althanstrasse 14, 1090 Vienna, Austria
| | - Patrick Bukenberger
- Department of Palaeontology, University of Vienna, Althanstrasse 14, 1090 Vienna, Austria
| | - Annekatrin Julie Enge
- Department of Palaeontology, University of Vienna, Althanstrasse 14, 1090 Vienna, Austria
| | - Maximillian Gerg
- Department of Palaeontology, University of Vienna, Althanstrasse 14, 1090 Vienna, Austria
| | - Wolfgang Wanek
- Department of Microbiology and Ecosystem Science, Terrestrial Ecosystem Research, University of Vienna, Althanstrasse 14, 1090 Vienna, Austria
| | - Margarete Watzka
- Department of Microbiology and Ecosystem Science, Terrestrial Ecosystem Research, University of Vienna, Althanstrasse 14, 1090 Vienna, Austria
| | - Petra Heinz
- Department of Palaeontology, University of Vienna, Althanstrasse 14, 1090 Vienna, Austria
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