The impact of biogeochemical processes on the composition of dissolved organic matter in marine subsurface sediments

Organic matter in marine sediments is one of the largest pools of reduced carbon on Earth. It had been known as recalcitrant carbon pool with scarce living biomasses. The findings of microbes at several kilometers below seafloor suggest there is a substantial amount of living biomasses in the subsurface sediments under extreme conditions, for example, decreasing labile biomolecules as carbon sources, electron acceptors, and thermal conditions at deeper layers. Those microbes might drive a slow but extensive carbon flow and play an important role in the carbon cycle in deep Earth. It is not known how the microbes could survive on the recalcitrant organic matter (ROM) leftover . The gap of knowledge is especially in the initial step of degradation process: how the ROM is degraded to assimilable substrates. Dissolved organic matter (DOM) encompasses the analytical window for the initial degradation of ROM. However, the DOM pool is complex and comprises tens of thousands of formulae. Therefore, this study focused on firstly the method of DOM characterization, secondly the DOM cycling and degradation process in subseafloor sediment. In further, this study aims to answer the questions: how the degradation patterns of organic matter change with environmental condition in the subsurface sediments, which are highly stratified by redox conditions and thermal gradients. In summary, this dissertation addressed the interactions between microbes and DOM in stratified anaerobic sediments by combinations of EEMs and FT-ICR MS. It is indicated that the metabolism of microbes is sensitive and adaptive to environmental conditions, which ultimately influence the carbon and nitrogen flow in subsurface sediments due to the change of microbial metabolisms and abiotic processes

Molecular Composition of Dissolved Organic Matter in the Changjiang (Yangtze River) – Imprints of Anthropogenic Impact

Understanding the biogeochemical transformation of dissolved organic matter (DOM) across fluvial networks will ultimately help to predict anthropogenic influences. To date, few studies have evaluated the anthropogenic impact on the spatial and temporal changes of DOM composition in large river systems. Here, FT-ICR-MS combined with excitation-emission matrix spectroscopy (EEMs) and biomarkers were applied to resolve chemical differences of DOM collected from the Changjiang basin at different hydrological and environmental conditions. PCA and cluster analysis illustrated that samples collected from lake systems and northern and southern tributaries differed from the two batches of main stream samples, particularly due to higher contribution of nitrogen and sulfur containing compounds. Correlation of land-use information along the tributaries with different PCA loadings indicated that agricultural, forest and wetland areas and wastewater discharge control the composition of DOM within these subregions. Higher heteroatom content (especially CHONx) in the low discharge period (2009) may be contributed by paddy soil leaching into groundwater. The relative peak magnitude of sulfur containing formulas was elevated during flood season (2010), which may be related to pollutions in areas of high population density. In addition, lignin phenol concentrations were higher in the flood season because of elevated soil erosion. Consequently, land use and human activities can strongly alter the quality and composition of DOM in watersheds flowing through densely populated regions, which may also impact or influence the riverine carbon flux in anthropogenically disturbed river systems

Der Einfluss biogeochemischer Prozesse auf die Zusammensetzung gelöster organischer Stoffe in marinen Untergrundsedimenten

Organic matter in marine sediments is one of the largest pools of reduced carbon on Earth. It had been known as recalcitrant carbon pool with scarce living biomasses. The findings of microbes at several kilometers below seafloor suggest there is a substantial amount of living biomasses in the subsurface sediments under extreme conditions, for example, decreasing labile biomolecules as carbon sources, electron acceptors, and thermal conditions at deeper layers. Those microbes might drive a slow but extensive carbon flow and play an important role in the carbon cycle in deep Earth. It is not known how the microbes could survive on the recalcitrant organic matter (ROM) leftover . The gap of knowledge is especially in the initial step of degradation process: how the ROM is degraded to assimilable substrates. Dissolved organic matter (DOM) encompasses the analytical window for the initial degradation of ROM. However, the DOM pool is complex and comprises tens of thousands of formulae. Therefore, this study focused on firstly the method of DOM characterization, secondly the DOM cycling and degradation process in subseafloor sediment. In further, this study aims to answer the questions: how the degradation patterns of organic matter change with environmental condition in the subsurface sediments, which are highly stratified by redox conditions and thermal gradients. In summary, this dissertation addressed the interactions between microbes and DOM in stratified anaerobic sediments by combinations of EEMs and FT-ICR MS. It is indicated that the metabolism of microbes is sensitive and adaptive to environmental conditions, which ultimately influence the carbon and nitrogen flow in subsurface sediments due to the change of microbial metabolisms and abiotic processes

Effects of Canopy Microclimate on Chinese Chestnut (Castanea mollissima Blume) Nut Yield and Quality

There are considerable differences in chestnut yield and quality across different chestnut-producing regions in China, indicating that environmental factors affect these properties of chestnuts. Furthermore, nut yield and quality differ depending on canopy position. Therefore, this study investigated the relationship between the canopy microclimate, nut yield, and quality. We determined microclimate factors from blossoming to ripening at different positions in the canopy. Nut yield and quality and the number of different branch types were measured at various canopy positions. The light intensity and temperature of the different canopy layers exhibited funnel-form distributions ranging from 0 to 3600 μmol·m2·s−1 and from 32 to 37 °C, respectively. Canopy humidity showed an inverted funnel-shaped distribution ranging from 26% to 40%. Nut yield and quality in the top and outer canopies were higher than in the bottom and inner canopies. Branches in the top-middle and peripheral parts of the canopy also produced higher yields, especially strong branches that bore more nuts. Nut yield and quality had positive correlations with light intensity (r = 0.735) and temperature (r = 0.709), whereas they were inversely associated with humidity (r = −0.584). The nut yield was more than 200 gm−3 when the light intensity was above 1500 μmol·m2·s−1, the temperature was above 34.4 °C, and the humidity was below 27.5%

Pattern of Lymphatic Metastasis and In fluencing Factors in Thoracic Esophageal Carcinoma

OBJECTIVE To explore the regular patterns of lymphatic metastasis in thoracic esophageal carcinoma (TEC) and the factors influencing these pa t erns. METHODS Data of 229 TEC patients who underwent radical esophagectomy and thoracoabdominal 2- field lymphadenectomy were reviewed. Within this patient population, a total of 2458 lymph nodes were dissected during surgery. The distribution of the nodular metastasis rates (NMR) in various diseased regions in the esophageal carcinoma (EC) patients as well as factors influencing metastases such as the depth of tumor infiltration, tumor size, tumor morphology, and degree of tumor differentiation were analyzed. RESULTS i ) Lymphatic metastasis (LM) occurred in 102 EC cases, and the lymphatic metastasis rate (LMR) was 44.5% (102/229). The NMR was 9.5% (258/2458). ii ) The NMRs were 19.0%, 6.7%, 9.8% and 12.2% in the superior, middle and inferior mediastinum, and abdominal cavity, respectively, in patients with EC in the superior thoracic segment; 26.1%, 7.4%, 11.8% and 11.9% in the same sites of the mediastinum, respectively, in those with middle thoracic segment EC; and 0%, 1.6%, 5.3%, and 10.0%, respectively, in the same sites in those with inferior thoracic EC. iii ) The LMRs of the EC patients in stage-T1, T2, T3 and T4 were 28.6%, 43.8%, 47.6% and 31.3%, respectively, and the NMRs of the patients were 7.9%, 10.8%, 10.7% and 10.8%, respectively. There were no signifi cant differences between the LMR and the NMR of the EC patients in stage T1 to T4 ( χ2= 2.733, P = 0.435 and χ2= 0.686, P = 0.876). iv ) The LMR of the patients with the length of tumor ≤ 3 cm, > 3 cm and ≤ 5 cm, and > 5 cm were 45.2%, 43.4% and 46.2%, respectively, and the NMR according to the same range of the tumor size above were 9.1%, 11.6% and 11.7%, respectively. There were no signifi cant di ff erences between the groups ( χ2= 0.094, P = 0.954 and χ2= 3.933, P = 0.140). v ) The NMRs of the medullary, ulcerative, fungoid and sclerotic-type EC were 14.0%, 9.6%, 4.3% and 18.3%, respectively (χ2= 19.292, P = 0.000), among which the NMR of the fungoid-type EC was the lowest. The LMRs were 42.5% and 75.0%, respectively in the cases with squamous cell carcinoma (SqCC) and poorly differentiated SqCC ( χ2= 4.852, P = 0.028), and the NMRs were 9.5% and 18.6% correspondingly in the 2 groups (χ2= 11.323, P = 0.001). LM was commonly seen in the cases with poorly differentiated tumors. CONCLUSION Lymph node metastases of TEC spreads widely and can involve many regions. Metastasis can even be found in early stages of EC. Morphologic type and the degree of tumor differentiation are the main factors a ff ecting the LM

Discovery and Profiling of microRNAs at the Critical Period of Sex Differentiation in Xanthoceras sorbifolium Bunge

Research Highlights: The critical period of sex differentiation in Xanthoceras sorbifolium was investigated. Multiple microRNAs (miRNAs) were identified to influence female and male flower development, with some complementary functions. Background and Objectives: Xanthoceras sorbifolium Bunge is widely cultivated owing to its multipurpose usefulness. However, as a monoecious plant, the low female–male flowers ratio and consequent low seed yield are the main bottlenecks for industrial-scale development of seed utilization. MiRNAs play crucial regulatory roles in flower development and sex differentiation; therefore, we evaluated the roles of miRNAs in the critical period of sex differentiation in X. sorbifolium. Materials and Methods: Four small RNA libraries for female and male flower buds of the critical period of sex differentiation were constructed from paraffin-embedded sections. The miRNAs were characterized by high-throughput sequencing, and differentially expressed miRNAs were validated by reverse transcription-quantitative polymerase chain reaction. Results: There were obvious differences in male and female pistil and stamen flower buds, with elongated inflorescence and clear separation of flower buds marking the critical period of sex differentiation. A total of 1619 conserved miRNAs (belonging to 34 families) and 219 novel miRNAs were identified. Among these, 162 conserved and 14 novel miRNAs exhibited significant differential expression in the four libraries, and 1677 putative target genes of 112 differentially expressed miRNAs were predicted. These target genes were involved in diverse developmental and metabolic processes, including 17 miRNAs directly associated with flower and gametophyte development, mainly associated with carbohydrate metabolism and glycan biosynthesis and metabolism pathways. Some miRNA functions were confirmed, and others were found to be complemented. Conclusions: Multiple miRNAs closely related to sex differentiation in X. sorbifolium were identified. The theoretical framework presented herein might guide sex ratio regulation to enhance seed yield

Bilinear Attention Network for Image-Based Fine-Grained Recognition of Oil Tea (<i>Camellia oleifera</i> Abel.) Cultivars

Oil tea (Camellia oleifera Abel.) is a high-quality woody oil crop unique to China and has extremely high economic value and ecological benefits. One problem in oil tea production and research is the worldwide confusion regarding oil tea cultivar nomenclature. The purpose of this study was to automatic recognize some oil tea cultivars using bilinear attention network. For this purpose, we explored this possibility utilizing the bilinear attention network for five common China cultivars Ganshi 83-4, Changlin 53, Changlin 3, Ganshi 84-8, and Gan 447. We adopted the bilinear EfficientNet-B0 network and the convolutional block attention module (CBAM) to build BA-EfficientNet model being able to automatically and accurately recognize oil tea cultivars. In addition, the InceptionV3, VGG16, and ResNet50 algorithms were compared with the proposed BA-EfficientNet. The comparative test results show that BA-EfficientNet can accurately recognize oil tea cultivars in the test set, with overall accuracy and kappa coefficients reaching 91.59% and 0.89, respectively. Compared with algorithms such as InceptionV3, VGG16, and ResNet50, the BA-EfficientNet algorithm has obvious advantages in most evaluation indicators used in the experiment. In addition, the ablation experiments were designed to quantitatively evaluate the specific effects of bilinear networks and CBAM modules on oil tea cultivar recognition results. The results demonstrate that BA-EfficientNet is useful for solving the problem of recognizing oil tea cultivars under natural conditions. This paper attempts to explore new thinking for the application of deep learning methods in the field of oil tea cultivar recognition under natural conditions

Effects of Canopy Position and Microclimate on Fruit Development and Quality of <i>Camellia oleifera</i>

Camellia oleifera is an economic tree species in southern China and is famous for its oil. The surrounding climate is filtered by the tree itself, resulting in the canopy microclimate, which affects the growth and fruit quality of C. oleifera. This study investigated the effect of canopy positions on microclimate and fruit growth, maturation and qualities by comparing the differences in canopy position. This study also considered the relationship between microclimate and fruit qualities during the oil conversion period. The fruit qualities and microclimate were studied by dividing the canopy into two vertical layers and horizontal layers, creating the following canopy positions: upper outer canopy (UO), upper inner canopy (UI), lower outer canopy (LO) and lower inner canopy (LI). The light intensity increased significantly from inside to outside and from top to bottom in the canopy; however, there were no significant differences in temperature and relative humidity. At maturity, the moisture content of fruits and kernels in UO and LO was approximately <5% of those in UI and LI. The soluble sugar content increased by 10.90%, 8.47% and 6.84% in UO, UI and LO in November, while no significant change was observed in LI. The kernel oil content (KOC) obtained a higher value in UO and UI at maturity. However, KOC decreased by 5.16%, 3.02%, 3.10% and 0.67% in UO, UI, LO and LI in November. Light intensity in September and October was correlated, and temperature and relative humidity in August and September were correlated

Transcriptomic and Metabolic Profiling Reveal the Mechanism of Ovule Development in <i>Castanea mollissima</i>

Ovule abortion, which is the main cause of empty burs in the Chinese chestnut, affects the formation of embryos and further reduces yield; therefore, it is important to study the mechanism of ovule abortion. In this study, we analyzed the transcriptomic and metabolomic data of ovules at critical developmental stages to explore the key regulatory networks affecting ovule development. The metabolites were enriched mainly in pathways involved in phytohormone signaling, energy metabolism, and amino acid synthesis in the endoplasmic reticulum. Analysis of the differentially expressed genes (DEGs) revealed that the HSP genes were significantly down-regulated during fertilization, indicating that this process is extremely sensitive to temperature. The hormone and sucrose contents of ovules before and after fertilization and of fertile and abortive ovules at different developmental stages showed significant differences, and it is hypothesized that that abnormal temperature may disrupt hormone synthesis, affecting the synthesis and catabolism of sucrose and ultimately resulting in the abortive development of Chinese chestnut ovules. At the pollination and fertilization stage of chestnuts, spraying with ethylene, ACC, and AIB significantly increased the number of developing fruit in each prickly pod compared to CK (water) treatment. These results indicated that both ethylene and ACC increased the rate of ovule development. This study provides an important theoretical molecular basis for the subsequent regulation of ovule development and nut yield in the Chinese chestnut