Slow Growth Rate Research Articles

Differentiating the roles of proteins and polysomes in nucleoid size homeostasis in Escherichia coli

A defining feature of the bacterial cytosolic interior is a distinct membrane-less organelle, the nucleoid, that contains the chromosomal DNA. Although increasing experimental evidence indicates that macromolecular crowding is the dominant mechanism for nucleoid formation, it has remained unclear which crowders control nucleoid volume. It is commonly assumed that polyribosomes play a dominant role, yet the volume fraction of soluble proteins in the cytosol is comparable with that of polyribosomes. Here, we develop a free energy-based model for the cytosolic interior of a bacterial cell to distinguish contributions arising from polyribosomes and cytosolic proteins in nucleoid volume control. The parameters of the model are determined from the existing experimental data. We show that, while the polysomes establish the existence of the nucleoid as a distinct phase, the proteins control the nucleoid volume in physiologically relevant conditions. Our model explains experimental findings in Escherichia coli that the nucleoid compaction curves in osmotic shock measurements do not depend on cell growth rate and that dissociation of polysomes in slow growth rates does not lead to significant nucleoid expansion, while the nucleoid phase disappears in fastest growth rates. Furthermore, the model predicts a cross-over in the exclusion of crowders by their linear dimensions from the nucleoid phase: below the cross-over of 30–50 nm, the concentration of crowders in the nucleoid phase decreases linearly as a function of the crowder diameter, while decreasing exponentially above the cross-over size. Our work points to the possibility that bacterial cells maintain nucleoid size and protein concentration homeostasis via feedback in which protein concentration controls nucleoid dimensions and the nucleoid dimensions control protein synthesis rate.

In vitro induction of tetraploidy and its effects on phenotypic variations in Populus hopeiensis

BackgroundArtificial induction of polyploidy is the most common and effective way to improve the biological properties of Populus and develop new varieties of this tree. In this study, in order to confirm and expand earlier findings, we established a protocol using colchicine and based on an efficient shoot regeneration system of leaf blades to induce tetraploidy in vitro in three genotypes from diploid Populus hopeiensis. The stomatal characteristics, leaf blade size, and growth were evaluated for diploids and tetraploids of three genotypes.ResultsWe found that genotype, preculture duration, colchicine concentration, and colchicine exposure time had highly significant effects on the tetraploid induction rate. The optimal protocol for inducing tetraploidy in P. hopeiensis was to preculture leaf blades for 7 days and then treat them for 4 days with 40 mg/L colchicine. The tetraploid induction rates of genotypes BT1, BT3, and BT8 were 21.2, 11.4 and 16.7%, respectively. A total of 136 tetraploids were identified by flow cytometry analysis and somatic chromosome counting. The stomatal length, width, and density of leaf blades significantly differed between diploid and tetraploid plants. Compared with their diploid counterparts, the tetraploids produced larger leaf blades and had a slower growth rate. Our findings further document the modified morphological characteristics of P. hopeiensis following whole-genome duplication (e.g., induced tetraploidy).ConclusionsWe established a protocol for in vitro induction of tetraploidy from diploid leaf blades treated with colchicine, which can be applied to different genotypes of P. hopeiensis.

The ontogenetic dimension of plant functional ecology

Abstract Plant functional strategies change considerably as plants develop, driven by intraindividual variability in anatomical, morphological, physiological and architectural traits. Developmental trait variation arises through the complex interplay among genetically regulated phase change (i.e. ontogeny), increases in plant age and size, and phenotypic plasticity to changing environmental conditions. Although spatial drivers of intraspecific trait variation have received extensive research attention, developmentally driven intraspecific trait variation is largely overlooked, despite widespread occurrence. Ontogenetic trait variation is genetically regulated, leads to dramatic changes in plant phenotypes and evolves in response to predictable changes in environmental conditions as plants develop. Evidence has accumulated to support a general shift from fast to slow relative growth rates and from shade to sun leaves as plants develop from the highly competitive but shady juvenile niche to the stressful adult niche in the systems studied to date. Nonetheless, there are major gaps in our knowledge due to examination of only a few environmental factors selecting for the evolution of ontogenetic trajectories, variability in how ontogeny is assigned, biogeographic sampling biases on trees in temperate biomes, dependencies on a few broadly sampled leaf morphological traits and a lack of longitudinal studies that track ontogeny within individuals. Filling these gaps will enhance our understanding of plant functional ecology and provide a framework for predicting the effects of global change threats that target specific ontogenetic stages. Read the free Plain Language Summary for this article on the Journal blog.

Unveiling a Biomarker Signature of Meningioma: The Need for a Panel of Genomic, Epigenetic, Proteomic, and RNA Biomarkers to Advance Diagnosis and Prognosis.

Meningiomas are the most prevalent primary intracranial tumors. The majority are benign but can undergo dedifferentiation into advanced grades classified by World Health Organization (WHO) into Grades 1 to 3. Meningiomas' tremendous variability in tumor behavior and slow growth rates complicate their diagnosis and treatment. A deeper comprehension of the molecular pathways and cellular microenvironment factors implicated in meningioma survival and pathology is needed. This review summarizes the known genetic and epigenetic aberrations involved in meningiomas, with a focus on neurofibromatosis type 2 (NF2) and non-NF2 mutations. Novel potential biomarkers for meningioma diagnosis and prognosis are also discussed, including epigenetic-, RNA-, metabolomics-, and protein-based markers. Finally, the landscape of available meningioma-specific animal models is overviewed. Use of these animal models can enable planning of adjuvant treatment, potentially assisting in pre-operative and post-operative decision making. Discovery of novel biomarkers will allow, in combination with WHO grading, more precise meningioma grading, including meningioma identification, subtype determination, and prediction of metastasis, recurrence, and response to therapy. Moreover, these biomarkers may be exploited in the development of personalized targeted therapies that can distinguish between the 15 diverse meningioma subtypes.

Live slow, die old: larval propagation of slow-growing, stress-tolerant corals for reef restoration

Efforts to restore coral reefs usually involve transplanting asexually propagated fast-growing corals. However, this approach can lead to outplanted populations with low genotypic diversity, composed of taxa susceptible to stressors such as marine heatwaves. Sexual coral propagation leads to greater genotypic diversity, and using slow-growing, stress-tolerant taxa may provide a longer-term return on restoration efforts due to higher outplant survival. However, there have been no reports to date detailing the full cycle of rearing stress-tolerant, slow-growing corals from eggs until sexual maturity. Here, we sexually propagated and transplanted two massive slow-growing coral species to examine long-term success as part of reef restoration efforts. Coral spat were settled on artificial substrates and reared in nurseries for approximately two years, before being outplanted and monitored for survivorship and growth for a further four years. More than half of initially settled substrates supported a living coral following nursery rearing, and survivorship was also high following outplantation with yields declining by just 10 to 14% over four years. At 6-years post-fertilisation over 90% of outplanted corals were reproductively mature, demonstrating the feasibility of restoring populations of sexually mature massive corals in under a decade. Although use of slower growing, stress tolerant corals for reef restoration may provide a longer-term return on investment due to high post-transplantation survival rates, considerable time is required to achieve even modest gains in coral cover due to their relatively slow rates of growth. This highlights the need to use a mix of species with a range of life-history traits in reef restoration and to improve survivorship of susceptible fast-growing taxa that can generate rapid increases in coral cover.

Influence of poly(methyl methacrylate) on the structure and phase transition behavior of poly(vinylidene fluoride)

The structure and organization of poly(vinylidene fluoride) (PVDF) spherulites in blends with poly(methyl methacrylate) of high (PMMA-H) and low (PMMA-L) molecular weights, respectively, have been studied in details. It is confirmed that the addition of PMMA-H and PMMA-L have different influence on the morphologies of PVDF spherulites in several aspects, such as the spacing of ring-band α-PVDF spherulites, the kinetics of both α-PVDF crystallization and α−γ′ solid phase transition, as well as the formation of Wagon-Wheel spherulites. First, incorporation of PMMA-L enlarges the band spacing, which is associated to the increased chain mobility of crystallizable PVDF that helps to release the surface stresses of lamellae. In contrast, the low mobility of PMMA-H chains enhances the congestion at fold surfaces, which results in a vigorous twisting and thus the formation of tightened ring-band α-PVDF structure. Second, the PMMA-H reduces the crystallization rate of PVDF more severely than the PMMA-L, resulting in an extremely slow growth rate of α-PVDF spherulites in PVDF/PMMA-H sample at 160 °C, only about one-twenty-third compared to the neat PVDF. Third, the remarkably reduced α-PVDF spherulite growth rate and enhanced α−γ′ transition rate at 160 °C lead to the formation of Wagon-Wheel PVDF spherulites with inner γ′-PVDF crystals and outer γ crystals. It originates from the synchronization of slow α-PVDF growth and accelerated α−γ′ transition rate through homoepitaxy. That is, when the α−γ′ transition with exceeded rate reaches the growth front of the original α-PVDF spherulite, the transformed γ′-PVDF crystals trigger the growth of γ-PVDF crystals directly from melt with non-band feature. These results help to unravel the formation mechanism of Wagon-Wheel PVDF spherulites to be the competition of α-γ′ crystal transformation and α-spherulite radial growth rates.

Gas–Water Two-Phase Displacement Mechanism in Coal Fractal Structures Based on a Low-Field Nuclear Magnetic Resonance Experiment

In this paper, the gas–water two-phase seepage process under a real mechanical environment is restored by a nuclear magnetic resonance experiment, and the gas–water two-phase distribution state and displacement efficiency in coal with different porosity under different gas injection pressures are accurately characterized. The fractal dimension of liquid phase distribution under different gas injection pressures was obtained through experiments, and the gas–water two-phase migration law is inverted according to it. Finally, the gas–water two-phase migration mechanism inside the fractal structure of coal was obtained. The results are as follows: 1. Gas will first pass through the dominant pathway (the composition of the dominant pathway is affected by porosity) and it will continue to penetrate other pathways only when the gas injection pressure is high. When the gas injection pressure is low, the displacement occurs mainly in the percolation pores. With the increase in gas injection pressure, the focus of displacement gradually shifts to the adsorption pore. 2. As the gas injection pressure increases, the displacement efficiency growth rate is relatively uniform for the high-porosity coal samples, while the low-porosity coal samples show a trend of first fast and then slow growth rates. When the gas injection pressure reaches 7 MPa, the displacement efficiency of high-porosity coal samples exceeds that of low-porosity coal samples. 3. With the increase in gas injection pressure, the fractal dimension of the adsorption pore section and the seepage pore section shows an increasing trend, but the fractal dimension of the adsorption pore section changes faster, indicating that with the increase in gas injection pressure, gas–water two-phase displacement mainly occurs in the adsorption pore section.

A test of island plant syndromes using resource‐use traits

AbstractDespite representing a fraction of the global terrestrial surface area, oceanic islands are disproportionately diverse in species, resulting from high rates of endemicity. Island plants are thought to share a unique phenotype—referred to as an island syndrome—which is thought to be driven by convergent evolution in response to selection by shared abiotic and biotic factors. One aspect of the island plant syndrome that has received relatively little research focus is that island plants are expected to have converged on conservative resource use associated with slow growth rates and weak competitive abilities. Here we tested whether native, woody Hawaiian plant species are phenotypically distinct—with more resource‐conservative leaf traits—compared to a globally distributed sample of continental species. Using an archipelago‐wide trait data set, we detected that on average, native Hawaiian species had lower leaf nutrient concentrations overall, and lower nutrient concentrations at high leaf mass per area, but no other phenotypic differences compared with continental plants. There was also considerable overlap in the trait spaces of native Hawaiian species and continental species. Our findings indicate that an island plant syndrome for leaf traits is not present in the Hawaiian flora, and that island species can demonstrate extensive variation in their resource‐use strategies, on a scale that is comparable with that of continental species worldwide.

Successful establishment of Anammox by cultivating residual sludge and its response to elevated nitrogen loading

Anaerobic ammonia oxidation (Anammox) process was one of the most economical nitrogen removal technology, however, the slow growth rate and the shortage of sufficient seed sludge limit its application. In this study, Anammox was successfully established using residual sludge as seed sludge, and the variation in its nitrogen removal, stability, and microbial characteristics in response to the elevated ammonia and nitrite were explored. The sludge exhibited Anammox activity on day 34, and the system was successfully established on day 67, while the hzo gene expression increased from 1.1 * 104 to 9.4 * 105 copies/mL. The established Anammox system showed good resistance to the high nitrogen shock (200–1000 mg/L), and the relative abundance of Candidatus_Kuenenia notably increased. However, when the total nitrogen in influent reached 1200 mg/L, the nitrogen removal of the Anammox system was suppressed. And Candidatus_Kuenenia abundance significantly decreased while Arenimonas increased. Residual sludge could be adopted for establishing Anammox system, and the system could be used for efficiently treating wastewater with nitrogen lower than 1000 mg/L. The result in the present study has significance to the application of Anammox process and deeply save the economic cost of seed sludge since residual sludge was widely available.

Determining SCC resistance of stainless steel claddings in high- temperature water by constant load crack growth tests and slow strain rate tests

Stress corrosion cracking (SCC) behaviors of 309 L and 308 L weld overlays are characterized in oxygen-free and oxygen-bearing high-temperature water using slow strain rate tests (SSRTs) and crack growth rate (CGR) tests with compact tension specimens. There is no apparent SCC indication on 308 L, while local SCC is observed on 309 L after SSRT in oxygen-free water. The SCC sensitivities of 308 L and 309 L increase with the increase of dissolved oxygen (DO) content, while 308 L shows relatively higher SCC resistance than 309 L in water with 200 ppb and 8000 ppb DO. SSRT and CGR test results show a similar effect of DO concentration on SCC of 309 L and 308 L. The fracture surface of 309 L exhibits extensive intergranular SCC, while 308 L shows only local interdendritic SCC after CGR tests. The crack tip blunting decreased the CGR in the low alloy steel. The highly island-shaped δ-ferrites and moderate strain hardening in 308 L contribute to its SCC resistance over 309 L.

Comparison of muscle structure and transcriptome analysis reveals the mechanism of growth variation in Yangtze sturgeon (Acipenser dabryanus)

Sturgeons display a slow growth rate and delayed initial sexual maturity, which extends the captive breeding and conservation processes. To date, few studies have revealed the molecular mechanism underlying the growth difference of sturgeons. In the present study, juvenile Yangtze sturgeons (Acipenser dabryanus) with different growth rates were selected from the same cultured pool for muscle structure, enzyme activity and comparative transcriptome analysis. Histological assays showed that the fiber diameter of the fast-growing group was significantly larger than that of the slow-growing group. The activities of four glycometabolism related enzymes, including two key rate-limiting enzymes hexokinase and pyruvate kinase, were significantly higher in fast-growing group. RNA-Seq of muscle tissues identified 7408 differentially expressed genes (DEGs), which consisted of 3637 upregulated genes and 3771 downregulated genes, in the fast-growing group vs. the slow-growing group. In the brain, a total of 12,213 unigenes were differentially expressed (6050 upregulated unigenes and 6163 downregulated unigenes) between the two groups. The expression levels of IGF1 and IGF1-binding proteins (IGFBPs) in muscle were significantly higher in the fast-growing group and might be promising candidate biomarkers for measuring growth performance in Yangtze sturgeon. Two myogenic regulatory factors (myog and myf6) were significantly upregulated, which indicated that the growth variation in juvenile Yangtze sturgeon might be partly due to the difference in the differentiation of muscle cells. In addition, pathway enrichment analysis revealed that the glycolysis and cell cycle pathways were significantly enhanced in the fast-growing groups, suggesting that they might also play important roles in the improved growth performance of A. dabryanus. Furthermore, the WGCNA as well as hub gene network analyses supported that cell cycle and gluconeogenesis might be involved in the differential growth performance of A. dabryanus. The results of this study may contribute to our understanding of the underlying molecular mechanism of growth variation in fish.

New insights into peroxide toxicology: sporulenes help Bacillus subtilis endospores from hydrogen peroxide.

The purpose of the present study was to understand the possible events involved in the toxicity of H2O2 to wild and sporulene-deficient spores of Bacillus subtilis, as H2O2 was previously shown to have deleterious effects. The investigation utilized two strains of B. subtilis, namely the wild-type PY79 (WT) and the sporulene-deficient TB10 (ΔsqhC mutant). Following treatment with 0.05% H2O2 (v/v), spore viability was assessed using a plate count assay, which revealed a significant decrease in cultivability of 80% for the ΔsqhC mutant spores. Possible reasons for the loss of spore viability were investigated with microscopic analysis, dipicholinic acid (DPA) quantification, and propidium iodide (PI) staining. Microscopic examinations revealed the presence of withered and deflated morphologies in spores of ΔsqhC mutants treated with H2O2, indicating a compromised membrane permeability. This was further substantiated by the absence of DPA and a high frequency (50-75%) of PI infiltration. The results of FAME analysis and protein profiling indicated that the potentiation of H2O2-induced cellular responses was manifested in the form of altered spore composition in ΔsqhC B. subtilis. The slowed growth rates of the ΔsqhC mutant and the heightened sporulene biosynthesis pathways in the wild-type strain, both upon exposure to H2O2, suggested a protective function for sporulenes in vegetative cells. Sporulenes serve as a protective layer for the inner membrane of spores, thus assuming a significant role in mitigating the adverse effects of H2O2 in WT B. subtilis. The toxic effects of H2O2 were even more pronounced in the spores of the ΔsqhC mutant, which lacks this protective barrier of sporulenes.

Performance of Various Chemicals Weed Management in Chickpea an Irrigated Environment

Chickpea is additional sensitive to weed competition than other crops. During early stages of crop growth competition is more severe because of slow growth rate and leaf area development. Weeds have been blamed for losses in India that range from 40 to 90 percent. Thus, adopting an effective weed management strategy is the only way to significantly increase chickpea yield. The experiment was conducted during Rabi season of 2011-12 at Agronomy Research Farm of NDUA&T, Kumarganj, Ayodhya, Uttar Pradesh. The experiment was laid out in randomized block design with fourteen weed management treatments and replicated in thrice. According to the findings, weed management methods significantly affect the number of nodules, nutrient (N, P, K) uptake, yields, and economics of chickpea over weedy check at growth stage. Maximum yield (1.72 t ha-1) and nutrient uptake (N- 63.60, P- 9.09 and K- 74.39 kg ha -1) by chickpea were recorded in weed free treatment but maximum nitrogen, phosphorous and potassium (23.22, 2.68 and 50.42 kg ha -1) uptake by weed were obtained in weedy check treatment and lowest in weed free treatment.

Small cyst size and slow growth rate are soothing features in individuals with pancreatic cysts undergoing surveillance

Small cyst size and slow growth rate are soothing features in individuals with pancreatic cysts undergoing surveillance

Food and light availability induce plastic responses in fire salamander larvae from contrasting environments.

Phenotypic plasticity has been proposed as a mechanism facilitating the colonisation and adaptation to novel environments, such as caves. However, phenotypic plasticity in subterranean environments remains largely unexplored. Here, we test for plasticity in growth and development of fire salamander larvae (Salamandra salamandra) from subterranean and surface habitats, in response to contrasting food availability and light conditions. We hypothesized that: (i) low food availability and absence of light decrease larval growth and delay metamorphosis, (ii) light conditions mediate the effects of food availability on growth and time to metamorphosis, and (iii) larval response to contrasting light and food conditions is shaped by the habitat of origin. Our study showed that reduced food availability significantly delayed metamorphosis and slowed total length and body mass growth rates, while exposure to constant darkness slowed body mass growth rate. However, larvae slowed growth rates and increased time to metamorphosis without compromising size at metamorphosis. The effect of food availability on growth and time to metamorphosis did not change under different light conditions. Fire salamanders from subterranean and surface habitats responded differently only in relation to contrasting food availability conditions. Specifically, larvae from the surface habitat grew faster in high food conditions, while growth in larvae from the subterranean habitat was not influenced by food availability. Initial size also appeared to be an influential factor, since larger and heavier larvae grew slower, metamorphosed faster, and the size advantage was maintained in newly-metamorphosed juveniles. Overall, the results of our experiment suggest that plasticity and local adaptation favor the exploitation of aquatic subterranean habitats for breeding by fire salamanders, allowing successful development even under food shortage and day-length constraints, without compromising metamorphic size. Our findings have implications for conservation because they confirm that phenotypic plasticity plays a critical role in allowing fire salamanders to overcome altered environmental conditions.

Kinetic characterization of gas mixture separation by hydrate method with 1,3-dioxolane and multi-walled carbon nanotubes complex synergistic system

In the transition to cleaner energy sources, low-carbon energy gases are expected to dominate fuel consumption. Hydrate-based gas separation technology is poised to play a key role in the decarbonization pathway for energy gases with high CO2 content. However, the current hydrate gas separation method faces challenges, including a long induction period, slow growth rate, and low separation efficiency. In light of these challenges, this paper investigates the kinetics of CH4/CO2 gas mixture hydrate formation and its separation efficiency in 1,3-dioxolane (DIOX) and multi-walled carbon nanotubes (MWCNTs). The experimental results showed that both DIOX and MWCNTs, when used in low concentrations, had a certain thermodynamic promotion effect, with DIOX showing a superior performance. DIOX outperforms MWCNTs in terms of gas consumption and induction time. whereas MWCNTs was superior to DIOX in terms of growth rate, and the purification rate at the same concentration could be increased by 32.66 %∼234.43 % compared with the DIOX system. Subsequently, this paper further investigated the effect of 300 ppm DIOX complexed with different concentrations of MWCNTs on hydrate formation and separation efficiency. DIOX was found to occupy the main promotional role in this complex system, retaining the growth acceleration stage in the DIOX system. When compounded with 200 ppm MWCNTs, the T90 time was shortened by 28.78 %∼59.29 %, and the purification rate could be increased by 86.4 % compared with a single 300 ppm DIOX system. This work provides guidance on the use and compounding of thermodynamic and kinetic promoters and aids hydrate technology where faster hydrate growth rates and more efficient gas mixture separation are required.

Effect of Working Capital, Debt Maturity, Sales, and Tangibility on Investment Efficiency

The research objective is to analyze variables such as working capital, debt maturity, sales and tangibility that affect investment efficiency. Investment is the activity of placing funds in one or more types of assets for a certain period to earn income. Factors that reflect company performance are the financial statements presented in the annual report. Underinvestment occurs when an investment company requires the use of large amounts of debt. Companies with overinvestment are companies that are in the mature stage with slow growth rates, and high cash flow. In this study the approach used is using quantitative methods. Then analyzed partial and multiple regression. The data used is secondary data. The independent variables used are working capital, debt maturity, sales, and tangibility. The dependent variable used is investment efficiency. The targeted output is to analyze whether the variables of working capital, debt maturity, sales and tangibility affect investment efficiency, so that with this research it is hoped that investment can be efficient.

Vicinity Vision Transformer.

Vision transformers have shown great success on numerous computer vision tasks. However, their central component, softmax attention, prohibits vision transformers from scaling up to high-resolution images, due to both the computational complexity and memory footprint being quadratic. Linear attention was introduced in natural language processing (NLP) which reorders the self-attention mechanism to mitigate a similar issue, but directly applying existing linear attention to vision may not lead to satisfactory results. We investigate this problem and point out that existing linear attention methods ignore an inductive bias in vision tasks, i.e., 2D locality. In this paper, we propose Vicinity Attention, which is a type of linear attention that integrates 2D locality. Specifically, for each image patch, we adjust its attention weight based on its 2D Manhattan distance from its neighbouring patches. In this case, we achieve 2D locality in a linear complexity where the neighbouring image patches receive stronger attention than far away patches. In addition, we propose a novel Vicinity Attention Block that is comprised of Feature Reduction Attention (FRA) and Feature Preserving Connection (FPC) in order to address the computational bottleneck of linear attention approaches, including our Vicinity Attention, whose complexity grows quadratically with respect to the feature dimension. The Vicinity Attention Block computes attention in a compressed feature space with an extra skip connection to retrieve the original feature distribution. We experimentally validate that the block further reduces computation without degenerating the accuracy. Finally, to validate the proposed methods, we build a linear vision transformer backbone named Vicinity Vision Transformer (VVT). Targeting general vision tasks, we build VVT in a pyramid structure with progressively reduced sequence length. We perform extensive experiments on CIFAR-100, ImageNet-1k, and ADE20K datasets to validate the effectiveness of our method. Our method has a slower growth rate in terms of computational overhead than previous transformer-based and convolution-based networks when the input resolution increases. In particular, our approach achieves state-of-the-art image classification accuracy with 50% fewer parameters than previous approaches.

Lake Evaporation and Its Effects on Basin Evapotranspiration and Lake Water Storage on the Inner Tibetan Plateau

AbstractEffects of lake evaporation (EW) on basin evapotranspiration (ETB) and lake water storage change (LWSC) at lake‐basin scale have never been reported for most basins on the inner Tibetan Plateau (IB). In this study, EW of 118 large lakes in 95 closed lake‐basins were estimated, and its effects on ETB and LWSC over 2001–2018 were examined using a derivative‐guided framework from the aspects of EW amount, rate, trend slope and inter‐annual variability. We found that EW amount has a high effect (17%) on regional ETB amount compared to the average lake area ratio (α) (∼5%), and the effect has increased significantly (2%/10 a). The spatial pattern of the effect is mainly controlled by α, and the increasing trend of α (0.6%/10 a) also dominated the increasing trend in regional ETB rate (0.30 mm/a) though with large spatial heterogeneity. Variance in α and EW rate have a minor effect (∼3%) on ETB variance, especially for the basins with lower α. The combination of quasi lake inflow (RL, 41%) and lake surface precipitation (PW, 16%) offset the depletion of EW (−43%), resulting in the surplus of regional lake water (LWSC > 0). The increase in EW mount, which is mainly from lake area expansion (90%), caused a decreasing trend in LWSC (i.e., slower growth rate) with a contribution of −59%. This suggests a negative feedback between lake area expansion and EW amount in the IB, and the feedback may continue with the predicted area increases.

Oyster reefs' control of carbonate chemistry-Implications for oyster reef restoration in estuaries subject to coastal ocean acidification.

Globally, oyster reef restoration is one of the most widely applied coastal restoration interventions. While reefs are focal points of processes tightly linked to the carbonate system such as shell formation and respiration, how these processes alter reef carbonate chemistry relative to the surrounding seawater is unclear. Moreover, coastal systems are increasingly impacted by coastal acidification, which may affect reef carbonate chemistry. Here, we characterized the growth of multiple constructed reefs as well as summer variations in pH and carbonate chemistry of reef-influenced seawater (in the middle of reefs) and ambient seawater (at locations ~50 m outside of reefs) to determine how reef chemistry was altered by the reef community and, in turn, impacts resident oysters. High frequency monitoring across three subtidal constructed reefs revealed reductions of daily mean and minimum pH (by 0.05-0.07 and 0.07-0.12 units, respectively) in seawater overlying reefs relative to ambient seawater (p < .0001). The proportion of pH measurements below 7.5, a threshold shown to negatively impact post-larval oysters, were 1.8×-5.2× higher in reef seawater relative to ambient seawater. Most reef seawater samples (83%) were reduced in total alkalinity relative to ambient seawater samples, suggesting community calcification was a key driver of modified carbonate chemistry. The net metabolic influence of the reef community resulted in reductions of CaCO3 saturation state in 78% of discrete samples, and juvenile oysters placed on reefs exhibited slower shell growth (p < .05) compared to oysters placed outside of reefs. While differences in survival were not detected, reef oysters may benefit from enhanced survival or recruitment at the cost of slowed growth rates. Nevertheless, subtidal restored reef communities modified seawater carbonate chemistry in ways that likely increased oyster vulnerability to acidification, suggesting that carbonate chemistry dynamics warrant consideration when determining site suitability for oyster restoration, particularly under continued climate change.