Calculating dissolved marine oxygen values based on an enhanced Benthic Foraminifera Oxygen Index.
Ontology highlight
ABSTRACT:
SUBMITTER: Kranner M
PROVIDER: S-EPMC8791969 | biostudies-literature |
REPOSITORIES: biostudies-literature
Similar Datasets
Project description:Bleaching, the loss of algal symbionts, occurs in marine photosymbiotic organisms at water temperatures minimally exceeding average summer SST (sea surface temperatures). Pre-adaptation allows organisms to persist under warmer conditions, providing the tolerance can be carried to new habitats. Here we provide evidence for the existence of such adaptation in the benthic foraminifera Pararotalia calcariformata. This species occurs at a thermally polluted site in the Mediterranean, where water temperatures reach a maxima daily average of 36?°C during the summer. To test whether this occurrence represents a widespread adaptation, we conducted manipulative experiments exposing this species from an unpolluted site to elevated temperatures (20-42?°C). It was kept in co-culture with the more thermally sensitive foraminifera Amphistegina lobifera in two experiments (20-36?°C). Reduced photosynthetic activity in A. lobifera occurred at 32?°C whereas photochemical stress in P. calcariformata was first observed during exposure to 36?°C. Pararotalia calcariformata survived all treatment conditions and grew under 36?°C. The photosymbiosis in P. calcariformata is unusually thermally tolerant. These observations imply that marine eukaryote-eukaryote photosymbiosis can respond to elevated temperatures by drawing on a pool of naturally occurring pre-adaptations. It also provides a perspective on the massive occurrence of symbiont-bearing foraminifera in the early Cenozoic hothouse climate.
| S-EPMC4977509 | biostudies-literature
Project description:Site U1489 was drilled during the International Ocean Discovery Program (IODP) Expedition 363 and is located on the western slope of the southern Eauripik Rise (2.12°N, 141.03°E, 3421 m water depth). We collected 183 samples from the upper ∼84 m of Site U1489 with an average sampling interval of ~50 cm, and performed the analyses of sediment washing and sieving, benthic foraminifera stable carbon and oxygen isotopes, and the relative abundance of selected benthic foraminifera. The data of these analyses are discussed in "Possible linkage between the long-eccentricity marine carbon cycle and the deep-Pacific circulation: Western equatorial Pacific benthic foraminifera evidences of the last 4Ma" [1], which provide a series of Plio-Pleistocene records of the western equatorial Pacific serving for regional and global comparisons of changes in the deep Pacific water mass properties and circulation.
| S-EPMC6941137 | biostudies-literature
Project description:High input of organic carbon and/or slowly renewing bottom waters frequently create periods with low dissolved oxygen concentrations on continental shelves and in coastal areas; such events can have strong impacts on benthic ecosystems. Among the meiofauna living in these environments, benthic foraminifera are often the most tolerant to low oxygen levels. Indeed, some species are able to survive complete anoxia for weeks to months. One known mechanism for this, observed in several species, is denitrification. For other species, a state of highly reduced metabolism, essentially a state of dormancy, has been proposed but never demonstrated. Here, we combined a 4 weeks feeding experiment, using 13C-enriched diatom biofilm, with correlated TEM and NanoSIMS imaging, plus bulk analysis of concentration and stable carbon isotopic composition of total organic matter and individual fatty acids, to study metabolic differences in the intertidal species Ammonia tepida exposed to oxic and anoxic conditions. Strongly contrasting cellular-level dynamics of ingestion and transfer of the ingested biofilm components were observed between the two conditions. Under oxic conditions, within a few days, intact diatoms were ingested, degraded, and their components assimilated, in part for biosynthesis of different cellular components: 13C-labeled lipid droplets formed after a few days and were subsequently lost (partially) through respiration. In contrast, in anoxia, fewer diatoms were initially ingested and these were not assimilated or metabolized further, but remained visible within the foraminiferal cytoplasm even after 4 weeks. Under oxic conditions, compound specific 13C analyses showed substantial de novo synthesis by the foraminifera of specific polyunsaturated fatty acids (PUFAs), such as 20:4(n-6). Very limited PUFA synthesis was observed under anoxia. Together, our results show that anoxia induced a greatly reduced rate of heterotrophic metabolism in Ammonia tepida on a time scale of less than 24 hours, these observations are consistent with a state of dormancy.
| S-EPMC5451005 | biostudies-literature
Project description:The negative consequences of fossil fuel burning for the oceans will likely include warming, acidification and deoxygenation, yet predicting future deoxygenation is difficult. Sensitive proxies for oxygen concentrations in ancient deep-ocean bottom-waters are needed to learn from patterns of marine deoxygenation during global warming conditions in the geological past. Understanding of past oxygenation effects related to climate change will better inform us about future patterns of deoxygenation. Here we describe a new, quantitative biological proxy for determining ocean paleo-oxygen concentrations: the surface area of pores (used for gas exchange) in the tests of deep-sea benthic foraminifera collected alive from 22 locations (water depths: 400 to 4100 m) at oxygen levels ranging from ~ 2 to ~ 277 μmol/l. This new proxy is based on species that are widely distributed geographically, bathymetrically and chronologically, and therefore should have broad applications. Our calibration demonstrates a strong, negative logarithmic correlation between bottom-water oxygen concentrations and pore surface area, indicating that pore surface area of fossil epifaunal benthic foraminifera can be used to reconstruct past changes in deep ocean oxygen and redox levels.
| S-EPMC6013501 | biostudies-literature
Project description:While shifts from coral to seaweed dominance have become increasingly common on coral reefs and factors triggering these shifts successively identified, the primary mechanisms involved in coral-algae interactions remain unclear. Amongst various potential mechanisms, algal exudates can mediate increases in microbial activity, leading to localized hypoxic conditions which may cause coral mortality in the direct vicinity. Most of the processes likely causing such algal exudate induced coral mortality have been quantified (e.g., labile organic matter release, increased microbial metabolism, decreased dissolved oxygen availability), yet little is known about how reduced dissolved oxygen concentrations affect competitive dynamics between seaweeds and corals. The goals of this study were to investigate the effects of different levels of oxygen including hypoxic conditions on a common hermatypic coral Acropora yongei and the common green alga Bryopsis pennata. Specifically, we examined how photosynthetic oxygen production, dark and daylight adapted quantum yield, intensity and anatomical distribution of the coral innate fluorescence, and visual estimates of health varied with differing background oxygen conditions. Our results showed that the algae were significantly more tolerant to extremely low oxygen concentrations (2-4 mg L(-1)) than corals. Furthermore corals could tolerate reduced oxygen concentrations, but only until a given threshold determined by a combination of exposure time and concentration. Exceeding this threshold led to rapid loss of coral tissue and mortality. This study concludes that hypoxia may indeed play a significant role, or in some cases may even be the main cause, for coral tissue loss during coral-algae interaction processes.
| S-EPMC3898309 | biostudies-literature
Project description:This dataset supports the paper entitled "A baseline investigation of benthic foraminifera in relation to marine sediments parameters in western parts of the Arabian Gulf". Duplicate sediment samples (sets A and B) were collected from 30 stations in an area covering approximately 25000 km2 in the offshore northern Arabian Gulf, using a van Veen grab (0.1 m2 area) and the top 1 cm was analysed for living benthic foraminifera. A set of samples was devoted to foraminiferal analysis while the other, set B, for sediment analyses. In situ hydrographical parameters such as temperature, salinity, pH, turbidity and DO were measured at surface waters. The top 1 cm was subsampled for foraminiferal analyses from the grab and preserved using 70% ethanol with Rose-Bengal stain. Potentially Toxic Elements (PTE) levels in sediment and grain size distributions were analysed. The dataset is expected to provide a baseline for PTE levels in sediment, benthic foraminiferal communities, and identify endemic species adapted to extremes of temperature and saline conditions typical of the Gulf. It can also be used by environmental managers, micropaleotologists, students in environmental/geology/marine science as reference background conditions based on sediment toxicity and benthic community information in revising environmental guidelines in the region. Data from this study suggest that PTEs are within the range of background values, and the sediments support highly diversified and stable benthic foraminiferal communities adapted to the unique environmental conditions in the Gulf. To date, this dataset documents the highest number of living benthic foraminifera species reported from the Gulf, and the most diverse living community compared to all previous studies. It also provides evidence for the full recovery of areas impacted during the 1991 Gulf oil spill which is evident by the diverse and flourishing assemblages of living benthic foraminifera documented.
| S-EPMC6948127 | biostudies-literature
Project description:A challenge of achieving intelligent marine ranching is the prediction of dissolved oxygen (DO). DO directly reflects marine ranching environmental conditions. Through accurate DO predictions, timely human intervention can be made in marine pasture water environments to avoid problems such as reduced yields or marine crop death due to low oxygen concentrations in the water. We use an enhanced semi-naive Bayes model for prediction based on an analysis of DO data from marine pastures in northeastern China from the past three years. Based on the semi-naive Bayes model, this paper takes the possible values of a DO difference series as categories, counts the possible values of the first-order difference series and the difference series of the interval before each possible value, and selects the most probable difference series value at the next moment. The prediction accuracy is optimized by adjusting the attribute length and frequency threshold of the difference sequence. The enhanced semi-naive Bayes model is compared with LSTM, RBF, SVR and other models, and the error function and Willmott's index of agreement are used to evaluate the prediction accuracy. The experimental results show that the proposed model has high prediction accuracy for DO attributes in marine pastures.
| S-EPMC8205303 | biostudies-literature
Project description:Foraminifera are an important faunal element of the benthos in oxygen-depleted settings such as Oxygen Minimum Zones (OMZs) where they can play a relevant role in the processing of phytodetritus. We investigated the uptake of phytodetritus (labeled with (13)C and (15)N) by calcareous foraminifera in the 0-1 cm sediment horizon under different oxygen concentrations within the OMZ in the eastern Arabian Sea. The in situ tracer experiments were carried out along a depth transect on the Indian margin over a period of 4 to 10 days. The uptake of phytodetrital carbon within 4 days by all investigated species shows that phytodetritus is a relevant food source for foraminifera in OMZ sediments. The decrease of total carbon uptake from 540 to 1100 m suggests a higher demand for carbon by species in the low-oxygen core region of the OMZ or less food competition with macrofauna. Especially Uvigerinids showed high uptake of phytodetrital carbon at the lowest oxygenated site. Variation in the ratio of phytodetrital carbon to nitrogen between species and sites indicates that foraminiferal carbon and nitrogen use can be decoupled and different nutritional demands are found between species. Lower ratio of phytodetrital carbon and nitrogen at 540 m could hint for greater demand or storage of food-based nitrogen, ingestion, or hosting of bacteria under almost anoxic conditions. Shifts in the foraminiferal assemblage structure (controlled by oxygen or food availability) and in the presence of other benthic organisms are likely to account for observed changes in the processing of phytodetritus in the different OMZ habitats. Foraminifera dominate the short-term processing of phytodetritus in the OMZ core but are less important in the lower OMZ boundary region of the Indian margin as biological interactions and species distribution of foraminifera change with depth and oxygen levels.
| S-EPMC4749719 | biostudies-literature
Project description:The balance between sources and sinks of molecular oxygen in the oceans has greatly impacted the composition of Earth's atmosphere since the evolution of oxygenic photosynthesis, thereby exerting key influence on Earth's climate and the redox state of (sub)surface Earth. The canonical source and sink terms of the marine oxygen budget include photosynthesis, respiration, photorespiration, the Mehler reaction, and other smaller terms. However, recent advances in understanding cryptic oxygen cycling, namely the ubiquitous one-electron reduction of O2 to superoxide by microorganisms outside the cell, remains unexplored as a potential player in global oxygen dynamics. Here we show that dark extracellular superoxide production by marine microbes represents a previously unconsidered global oxygen flux and sink comparable in magnitude to other key terms. We estimate that extracellular superoxide production represents a gross oxygen sink comprising about a third of marine gross oxygen production, and a net oxygen sink amounting to 15 to 50% of that. We further demonstrate that this total marine dark extracellular superoxide flux is consistent with concentrations of superoxide in marine environments. These findings underscore prolific marine sources of reactive oxygen species and a complex and dynamic oxygen cycle in which oxygen consumption and corresponding carbon oxidation are not necessarily confined to cell membranes or exclusively related to respiration. This revised model of the marine oxygen cycle will ultimately allow for greater reconciliation among estimates of primary production and respiration and a greater mechanistic understanding of redox cycling in the ocean.
| S-EPMC7035516 | biostudies-literature
Project description:Microbiome across depth in large benthic Foraminifera
| PRJEB24719 | ENA