Laboratory Assessment of the Impact of Chemical Oxidation, Mineral Dissolution, and Heating on the Nitrogen Isotopic Composition of Fossil‐Bound Organic Matter

Geochemistry Geophysics Geosystems, Journal Year: 2022, Volume and Issue: 23(8)

Published: Aug. 1, 2022

Abstract Fossil‐bound organic material holds great potential for the reconstruction of past changes in nitrogen (N) cycling. Here, with a series laboratory experiments, we assess effect oxidative degradation, fossil dissolution, and thermal alteration on fossil‐bound N isotopic composition different types, including deep shallow water scleractinian corals, foraminifera, diatoms tooth enamel. Our experiments show that exposure to oxidizing reagents does not significantly affect or content any types analyzed, demonstrating matter is well protected from surrounding environment by mineral matrix. In addition, partial dissolution (of up 70%–90%) aragonite, calcite, opal, enamel matrixes has negligible fossils. These results suggest relatively uniform, also exposed during lost without significant discrimination. Finally, our heating all at 100°C. At 200°C hotter, loss associated isotope appear be directly linked sensitivity matrix stress, which depends biomineral type. that, so long as high temperature compromise structure, acts closed system respect N, remains unchanged.

Language: Английский

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Past changes in and present status of the coastal carbon cycle

Cambridge Prisms Coastal Futures, Journal Year: 2023, Volume and Issue: 1

Published: Jan. 1, 2023

Abstract Data were obtained from the literature to identify past changes in and present status of coastal carbon cycle. They indicate that marine ecosystems driving cycle cover, on average, 5.8% Earth’s surface contributed 55.2% transport climate-active geological The data suggest humans not only increase CO 2 concentration atmosphere but also mitigate (and before 1860 even balanced) their emissions by increasing storage within ecosystems. Soil degradation response expansion intensification agriculture is assumed be a key process enhanced because it increases supply lithogenic matter known favour burial organic sediments. After 1860, rising concentrations caused land-use burning fossil fuel disturbed what was quasi-steady state before. Ecosystem restoration potential forest cover could atmospheric concentrations, this sink much too weak represent an alternative reduction emission order keep global warming below 1.5–2.°C. Although contribution benthic uptake ecosystem around 6%, significant given national budgets. However, impact climate still difficult quantify associated effects CH 4 N O have been established. Addressing these uncertainties one challenges faced future research, as are related issues concerning estimates fluxes between development suitable methods pelagic ocean.

Language: Английский

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Knowledge Gaps in Quantifying the Climate Change Response of Biological Storage of Carbon in the Ocean

Earth s Future, Journal Year: 2024, Volume and Issue: 12(6)

Published: June 1, 2024

Abstract The ocean is responsible for taking up approximately 25% of anthropogenic CO 2 emissions and stores >50 times more carbon than the atmosphere. Biological processes in play a key role, maintaining atmospheric levels 200 ppm lower they would otherwise be. ocean's ability to take store sensitive climate change, however biological that contribute storage are uncertain, as how those will respond to, feedback on, change. As result, biogeochemical models vary widely their representation relevant processes, driving large uncertainties projections future storage. This review identifies affect may change three thematic areas: contributions alkalinity, net primary production, interior respiration. We undertook existing literature identify with high importance influencing biologically‐mediated ocean, prioritized on basis both an expert assessment community survey. Highly ranked survey were: alkalinity—high level understanding calcium carbonate production; production—resource limitation growth, zooplankton phytoplankton loss processes; respiration—microbial solubilization, particle characteristics type. analysis presented here designed support field or laboratory experiments targeting new process understanding, modeling efforts aimed at undertaking model development.

Language: Английский

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Partitioning the Export of Distinct Biogenic Carbon Pools in the Northeast Pacific Ocean Using a Biogeochemical Profiling Float

Global Biogeochemical Cycles, Journal Year: 2022, Volume and Issue: 36(2)

Published: Jan. 8, 2022

Abstract We leverage observations from chemical and bio‐optical sensors mounted on a biogeochemical profiling float in the Northeast Pacific Ocean to quantify cycling export potential of distinct biogenic carbon pools, including particulate inorganic (PIC), organic (POC), dissolved (DOC). Year‐round reveal complex cycle dynamics among these pools. Net DOC production peaked during bloom initiation, about 3 months prior summer peak POC production. validate estimates with seasonal accumulation removal rates derived ship‐board over same period. By combining tracers cycling, we estimate instantaneous sinking flux ( ). The cooccurrence consumption fall winter resolves regional conundrum persistent particle observed by sediment traps season that is known be heterotrophic. PIC small, uncertainties are large. float‐based net primary (NPP) , real‐time ratio ([ /NPP] × 100%) for euphotic zone. Elevated ratios associated an increase fraction particles larger than 100 μm size. physical redistribution through deep mixing. Our study demonstrates how combined use multiple floats can provide more nuanced information upper ocean dynamics.

Language: Английский

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Marine biomaterials in biomedical nano/micro-systems

Journal of Nanobiotechnology, Journal Year: 2023, Volume and Issue: 21(1)

Published: Nov. 5, 2023

Abstract Marine resources in unique marine environments provide abundant, cost-effective natural biomaterials with distinct structures, compositions, and biological activities compared to terrestrial species. These marine-derived raw materials, including polysaccharides, protein components, fatty acids, minerals, etc., have shown great potential preparing, stabilizing, or modifying multifunctional nano-/micro-systems are widely applied drug delivery, theragnostic, tissue engineering, etc. This review provides a comprehensive summary of the most current biomaterial-based developed over past three years, primarily focusing on therapeutic delivery studies highlighting their cure variety diseases. Specifically, we first provided detailed introduction physicochemical characteristics biocomponents state. Furthermore, assembly processes, functionalities each building block, thorough evaluation pharmacokinetics pharmacodynamics advanced systems effects molecular pathophysiological processes were fully elucidated. Finally, list unresolved issues pivotal challenges applications, such as standardized distinction long-term biosafety vivo, feasibility scale-up, was presented. is expected serve roadmap for fundamental research facilitate rational design diverse emerging applications. Graphical

Language: Английский

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Global Trends in the Distribution of Biogenic Minerals in the Ocean

Journal of Geophysical Research Oceans, Journal Year: 2023, Volume and Issue: 128(2)

Published: Feb. 1, 2023

Abstract The cycling of marine particulate matter is critical for sequestering carbon in the deep ocean and sediments. Biogenic minerals such as calcium carbonate (CaCO 3 ) opal add density to more buoyant organic material, facilitating particle sinking export. Here, we compile analyze a global data set (POC), inorganic (PIC, or CaCO ), biogenic silica (bSi, opal) concentrations collected using large volume pumps (LVPs). We distribution all three phases small (1–53 μm) (>53 size classes. Over entire water column 76% POC exists fraction. Similarly, class contains 82% PIC, indicating importance small‐sized coccolithophores PIC budget ocean. In contrast, 50% bSi fraction, reflecting larger diatoms radiolarians compared with coccolithophores. use PIC:POC bSi:POC ratios upper document consistent signal shallow mineral dissolution, likely linked biologically mediated processes. Sediment trap are elevated respect LVP samples increase strongly depth, concentration and/or deficit particles. suggest that future sampling campaigns pair LVPs sediment traps capture full field, especially aggregates contribute mineral‐rich fluxes, may be missed by LVPs.

Language: Английский

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Genome‐wide phylogeography reveals cryptic speciation in the circumglobal planktonic calcifier Limacina bulimoides

Molecular Ecology, Journal Year: 2023, Volume and Issue: 32(12), P. 3200 - 3219

Published: March 21, 2023

Little is known about when and how planktonic species arise persist in the open ocean without apparent dispersal barriers. Pteropods are snails with thin shells susceptible to dissolution that used as bio-indicators of acidification. However, distinct evolutionary units respond acidification differently, defining boundaries therefore crucial for predicting impact changing conditions. In this global population genomic study shelled pteropod Limacina bulimoides, we combined genetic (759,000 single nucleotide polymorphisms) morphometric data from 161 individuals, revealing three major lineages (FST = 0.29-0.41): an "Atlantic lineage" sampled across Atlantic, "Indo-Pacific North Pacific Indian Ocean, a "Pacific South Pacific. A time-calibrated phylogeny suggests diverged 1 million years ago, estimated effective size remaining high (~10 million) throughout Pleistocene glacial cycles. We do not observe any signatures recent hybridization, even areas sympatry While reproductively isolated, they morphologically cryptic, overlapping shell shape colour distributions. Despite showing circumglobal L. bulimoides consists multiple smaller ranges than initially thought, found these pteropods still possess levels variability. Our adds growing evidence speciation often overlooked ocean, presence biological within many other currently defined species.

Language: Английский

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Laboratory Observation of the Buffering Effect of Aragonite Dissolution at the Seafloor

Journal of Geophysical Research Biogeosciences, Journal Year: 2024, Volume and Issue: 129(2)

Published: Feb. 1, 2024

Abstract Carbon dioxide entering and acidifying the ocean can be neutralized by dissolution of calcium carbonate, which is mainly found in two mineral forms. Calcite more stable form often deep‐sea sediments, whilst aragonite soluble therefore rarely preserved. Recent research shows may account for a much larger portion marine carbonate export to interior via biological pump than previously thought, that does reach deep sea seafloor despite being buried. If present dissolving at it will raise local pH concentrations, potentially enough inhibit calcite dissolution, representing deep‐sea, version galvanization. Here, we test this hypothesis simulating sediment‐water interface laboratory measuring its effects on using microsensors. We show addition sediment, overlain seawater undersaturated with respect both minerals, results an unchanged alkalinity flux out suggesting decrease net rate calcite. In combination diagenetic model, suppress top millimeters seabed, locally leading precipitation within 1 day. Future efforts should quantify galvanization effect situ, as process represent important component carbon cycle, assigning key role producers controlling preserving climatic archives.

Language: Английский

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Calcite carbonate sinks low-density plastic debris in open oceans

Nature Communications, Journal Year: 2024, Volume and Issue: 15(1)

Published: June 6, 2024

The vertical settling of plastic debris in oceans is poorly understood. A large share low-density microplastics (LDMPs) are largely absent from sea surfaces. present study employs a model that considers the potential an overlooked microbially induced calcium carbonate precipitation (MICP) process and new motion equations for irregular LDMPs. Here we show LDMPs model, exhibiting damped oscillation pattern, quite different biofouling models. Furthermore, size range 10-200 µm most likely to gain sufficient density at biofouling/MICP stage independently sink ocean floor with relatively small drag coefficients, potentially explaining selective enrichment oceanic sediment. shape exhibit strong non-linear effects on patterns Overall, highlights importance calcite-mediated sinking open oceans.

Language: Английский

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Cascading effects augment the direct impact of CO2 on phytoplankton growth in a biogeochemical model

Elementa Science of the Anthropocene, Journal Year: 2022, Volume and Issue: 10(1)

Published: Jan. 1, 2022

Atmospheric and oceanic CO2 concentrations are rising at an unprecedented rate. Laboratory studies indicate a positive effect of on phytoplankton growth until optimum is reached, after which the negative impact accompanying acidification dominates. Here, we implemented carbonate system sensitivities into our global biogeochemical model FESOM-REcoM accounted explicitly for coccolithophores as group most sensitive to CO2. In idealized simulations in solely atmospheric mixing ratio was modified, changes competitive fitness biomass not only caused by direct effects CO2, but also indirect via nutrient light limitation well grazing. These cascading can both amplify or dampen responses changing ocean pCO2 levels. For example, coccolithophore negatively affected directly future indirectly limitation, these compensated weakened resulting from decrease small-phytoplankton biomass. Southern Ocean, decreases hereby preferred prey zooplankton, reduces grazing pressure diatoms allows them proliferate more strongly. that encompass CO2-driven warming acidification, reveals recent observed North Atlantic driven primarily Our results highlight change other environmental drivers growth, may play important role projections net primary production.

Language: Английский

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