Syntheses of carbonate chemistry spatial patterns are important for predicting ocean acidification impacts, but are lacking in coastal oceans. Here, we show that along the North American Atlantic and ...Gulf coasts the meridional distributions of dissolved inorganic carbon (DIC) and carbonate mineral saturation state (Ω) are controlled by partial equilibrium with the atmosphere resulting in relatively low DIC and high Ω in warm southern waters and the opposite in cold northern waters. However, pH and the partial pressure of CO
(pCO
) do not exhibit a simple spatial pattern and are controlled by local physical and net biological processes which impede equilibrium with the atmosphere. Along the Pacific coast, upwelling brings subsurface waters with low Ω and pH to the surface where net biological production works to raise their values. Different temperature sensitivities of carbonate properties and different timescales of influencing processes lead to contrasting property distributions within and among margins.
Transformation and mobilization of bioessential elements in the biosphere, lithosphere, atmosphere, and hydrosphere constitute the Earth's biogeochemical cycles, which are driven mainly by ...microorganisms through their energy and material metabolic processes. Without microbial energy harvesting from sources of light and inorganic chemical bonds for autotrophic fixation of inorganic carbon, there would not be sustainable ecosystems in the vast ocean. Although ecological energetics (eco-energetics) has been emphasized as a core aspect of ecosystem analyses and microorganisms largely control the flow of matter and energy in marine ecosystems, marine microbial communities are rarely studied from the eco-energetic perspective. The diverse bioenergetic pathways and eco-energetic strategies of the microorganisms are essentially the outcome of biosphere-geosphere interactions over evolutionary times. The biogeochemical cycles are intimately interconnected with energy fluxes across the biosphere and the capacity of the ocean to fix inorganic carbon is generally constrained by the availability of nutrients and energy. The understanding of how microbial eco-energetic processes influence the structure and function of marine ecosystems and how they interact with the changing environment is thus fundamental to a mechanistic and predictive understanding of the marine carbon and nitrogen cycles and the trends in global change. By using major groups of chemolithoautotrophic microorganisms that participate in the marine nitrogen cycle as examples, this article examines their eco-energetic strategies, contributions to carbon cycling, and putative responses to and impacts on the various global change processes associated with global warming, ocean acidification, eutrophication, deoxygenation, and pollution. We conclude that knowledge gaps remain despite decades of tremendous research efforts. The advent of new techniques may bring the dawn to scientific breakthroughs that necessitate the multidisciplinary combination of eco-energetic, biogeochemical and "omics" studies in this field.
Shallow-sea hydrothermal systems experience continuous fluctuations of physicochemical conditions due to seawater influx which generates variable habitats, affecting the phylogenetic composition and ...metabolic potential of microbial communities. Until recently, studies of submarine hydrothermal communities have focused primarily on chemolithoautotrophic organisms, however, there have been limited studies on heterotrophic bacteria. Here, fluorescence
hybridization, high throughput 16S rRNA gene amplicon sequencing, and functional metagenomes were used to assess microbial communities from the shallow-sea hydrothermal system off Kueishantao Island, Taiwan. The results showed that the shallow-sea hydrothermal system harbored not only autotrophic bacteria but abundant heterotrophic bacteria. The potential for marker genes sulfur oxidation and carbon fixation were detected in the metagenome datasets, suggesting a role for sulfur and carbon cycling in the shallow-sea hydrothermal system. Furthermore, the presence of diverse genes that encode transporters, glycoside hydrolases, and peptidase indicates the genetic potential for heterotrophic utilization of organic substrates. A total of 408 cultivable heterotrophic bacteria were isolated, in which the taxonomic families typically associated with oligotrophy, copiotrophy, and phototrophy were frequently found. The cultivation-independent and -dependent analyses performed herein show that Alphaproteobacteria and Gammaproteobacteria represent the dominant heterotrophs in the investigated shallow-sea hydrothermal system. Genomic and physiological characterization of a novel strain P5 obtained in this study, belonging to the genus
within Alphaproteobacteria, provides an example of heterotrophic bacteria with major functional capacity presented in the metagenome datasets. Collectively, in addition to autotrophic bacteria, the shallow-sea hydrothermal system also harbors many heterotrophic bacteria with versatile genetic potential to adapt to the unique environmental conditions.
Open ocean mariculture can be established by the artificial upwelling of deep ocean water (DOW). However, one of the major obstacles is the difficulty of containing a nutrient-rich DOW plume without ...significant dilution. In this paper, the hydrodynamic design of DOW discharge for the creation of the DOW plume in the South China Sea (SCS) is presented. The trajectory and DOW concentration of the plume in a stratified ocean environment where a sharp density interface exists is investigated relative to the current speed, pumped water flow rate, pipe diameter and optimal depth of DOW discharge. A mathematical model is presented to ensure that a desirable nutrient concentration in the DOW plume can be maintained under specific ocean stratification and current conditions. The validity of the mathematical model is verified by a computational fluid dynamics (CFD) analysis on the flow and nutrient transport of the DOW plume. The results show that the volume concentration of DOW in the plume can be controlled by setting up the flow rate, pipe diameter and corresponding optimal DOW discharge depth. In this way, the nutrient-rich DOW plume can be sustained in the open ocean to stimulate marine primary productivity.
•We present the hydrodynamic design of DOW effluent discharge for the creation of a nutrient-rich plume.•We derive an algorithm for the optimum depth of the pipe outlet for the creation of a nutrient-rich plume.•We simulate the trajectory and dilution rate of a nutrient-rich DOW plume in a stratified ocean environment.•Nutrient concentrations of plume can be controlled by setting up the flow rate, pipe diameter and the depth of pipe outlet.•Marine primary productivity can be enhanced if proper technical parameters of the artificial upwelling device are designed.
Antibiotic resistance genes (ARGs) became an emerging contaminant, and were found to accumulate in natural and man-made environments. A comprehensive understanding of the diversity and abundance of ...ARGs in pristine environments is critical for defining the baseline levels of environmental ARGs. However, there is limited information available on the ARG profiles of pristine environments, especially for shallow-sea hydrothermal vents ecosystems. Here, we combined 16S rRNA gene full-length amplicon sequencing and high-throughput quantitative PCR (HT-qPCR) to study the bacterial communities, and ARG abundance and diversity in the shallow-sea hydrothermal vent ecosystem of the Kueishantao Islet. The results of the 16S rRNA gene amplicon sequencing showed that several sulfur-cycling related bacterial genera, including Thiomicrorhabdus, Thioreductor, Sulfurovum, Sulfurimonas and Lebetimonas, dominated in the water column of the shallow-sea system. Temperature was the significant factor shaping the bacterial communities. The results of HT-qPCR analysis showed that the Kueishantao shallow-sea system harbored the lowest diversity (average 10 ARG subtypes) and abundance (average 1.0 × 10−3 copy per bacterial cell) of ARGs compared with other pristine (i.e., Tibet lake sediments, marine water and sediments) and anthropogenic-disturbed (i.e., drinking water reservoirs, urban ponds and wastewater treatment plants) environments. Procrustes analysis demonstrated a concordant pattern between the compositions of bacterial communities and ARGs in the shallow-sea system, while variation partition analysis revealed that the shared effects of physicochemical and bacterial communities explained >80% of the variation in the composition of ARGs. These results suggest that the vent bacterial communities and local environmental factors played an important role in shaping the distribution of the ARG profiles. Our study provides the first comprehensive overview of the background level of ARGs in a shallow-sea hydrothermal vent ecosystem.
A hydrothermal vent system is one of the most unique marine environments on Earth. The cycling hydrothermal fluid hosts favorable conditions for unique life forms and novel mineralization mechanisms, ...which have attracted the interests of researchers in fields of biological, chemical and geological studies. Shallow-water hydrothermal vents located in coastal areas are suitable for hydrothermal studies due to their close relationship with human activities. This paper presents a summary of the developments in exploration and detection methods for shallow-water hydrothermal systems. Mapping and measuring approaches of vents, together with newly developed equipment, including sensors, measuring systems and water samplers, are included. These techniques provide scientists with improved accuracy, efficiency or even extended data types while studying shallow-water hydrothermal systems. Further development of these techniques may provide new potential for hydrothermal studies and relevant studies in fields of geology, origins of life and astrobiology.
The paleoclimate since 14 kyr BP (
14C age) was reconstructed based on a 16.22-m-long sediment core collected from Lake Yanhaizi, a saline lake located near the northern limit of the East Asian ...summer monsoon in Inner Mongolia. Coarse sediments were deposited there during a shrinkage phase of the lake when sand dunes reactivated. These sediments have low organic carbon contents but high maturity indices, indicating that they were deposited in an arid environment. By contrast, based on high organic contents and low maturity indices, fine sediments were deposited during periods of high lake stand in a humid environment. It was in general dry between 8.0 and 4.3 kyr BP. The above dry and wet phases are consistent with those recovered from the arid–semiarid transition zone elsewhere, but are unlike the widely perceived humid Holocene Megathermal reported in east China and the newly reconstructed record in the alpine Retreat Lake in Taiwan. The discrepancy may be due to a relative insensitivity to humidity changes in these two areas since they have both been under the total influence of the summer monsoon. On the other hand, much enhanced evaporation over higher monsoon precipitation at Lake Yanhaizi reduces the effective humidity in the warm climate near the northern boundary of the summer monsoon. This also accounts for the fact the high-temperature Holocene Megathermal, as revealed in the Okinawa Trough and the northern South China Sea, is correlated to the dry phases at Lake Yanhaizi. Conversely, the 4–2-kyr BP coldest period in the Holocene corresponds to a wet phase at Lake Yanhaizi.
Boron is a common element in vent fluids of seafloor hydrothermal fields, and it has been used to understand the hydrothermal flux and water-rock interaction in hydrothermal systems. We have measured ...the boron concentration and isotope composition of seawater, andesite, hydrothermal fluid and plume samples from the Kueishantao hydrothermal field. The delta 11B value of ambient seawater near the field is 40.05 plus or minus 0.01ppt, and the boron concentration is 3.81mg/L. Andesite rocks from the hydrothermal field have an average boron content of 15.3ppm. The hydrothermal fluids from the yellow spring and white spring span a small range of delta 11B values, from 33.27 plus or minus 0.22 to 36.84 plus or minus 0.11ppt, and plumes from both springs also cover a small range, from 37.56 plus or minus 0.01 to 40.37 plus or minus 0.21ppt. Hydrothermal fluids from both springs in the Kueishantao hydrothermal field have variable B enrichments relative to seawater between 7 and 21%. They have B concentrations (4.10-4.64mg/L) that are slightly higher and delta 11B values (33.27-36.84ppt) that are lower than those of the hydrothermal plumes (3.94-4.17mg/L, 37.56-40.37ppt). Hydrothermal fluids and plumes display a very regular array of data points in a delta 11B-B diagram, suggesting that the boron of hydrothermal fluids and plumes is mainly from seawater and that little of it is, from andesite. This implies that the interaction of subseafloor fluid and -andesite at the Kueishantao hydrothermal field is of short duration. In all the fluids, from springs to hydrothermal plumes, the pH values, B concentrations and B isotopic compositions show significant correlations with each other suggesting that the delta 11B/B and pH/B ratios of hydrothermal plumes have stable values over the small distance form vent to plume (<15m). Thus the B concentrations and B isotopic compositions of hydrothermal plumes can be used to describe the diffusive processes governing the chemical compositions of hydrothermal plumes in the seawater environment. The water/rock ratios, based on the B concentrations and delta 11B values, are between 1.96 and 3.63. The hydrothermal flux of boron from the yellow spring into the oceans is between 1.17105 mol/yr and 1.32105 mol/yr, and from the white spring it is between 6.69104 mol/yr and 7.17104 mol/yr, assuming that only andesites are present in the reaction zone.
Effective data management plays a key role in oceanographic research as cruise-based data, collected from different laboratories and expeditions, are commonly compiled to investigate regional to ...global oceanographic processes. Here we describe new and updated best practice data standards for discrete chemical oceanographic observations, specifically those dealing with column header abbreviations, quality control flags, missing value indicators, and standardized calculation of certain properties. These data standards have been developed with the goals of improving the current practices of the scientific community and promoting their international usage. These guidelines are intended to standardize data files for data sharing and submission into permanent archives. They will facilitate future quality control and synthesis efforts and lead to better data interpretation. In turn, this will promote research in ocean biogeochemistry, such as studies of carbon cycling and ocean acidification, on regional to global scales. These best practice standards are not mandatory. Agencies, institutes, universities, or research vessels can continue using different data standards if it is important for them to maintain historical consistency. However, it is hoped that they will be adopted as widely as possible to facilitate consistency and to achieve the goals stated above.
► We first report the trace and rare earth element compositions of native sulfur ball. ► The growth of the native sulfur ball is significantly slower than that of chimneys. ► A “glue pudding” growth ...model for understanding the origin of the native sulfur ball.
We first report the trace and rare earth element compositions of native sulfur ball with sulfur contents varying from 97.08
wt.% to 99.85
wt.% from the Kueishantao hydrothermal field, off NE Taiwan. We then discuss the sources of trace and rare earth elements incorporated into the native sulfur ball during formation. Comparison of our results with native sulfur from crater lakes and other volcanic areas shows the sulfur content of native sulfur ball from the Kueishantao hydrothermal field is very high, and that the rare earth element (REE) and trace element constituents of the native sulfur balls are very low (∑REE
<
35
ppb). In the native sulfur ball, V, Cr, Co, Ni, Nb, Rb, Cs, Ba, Pb, Th, U, Al, Ti and REE are mostly derived from andesite; Mg, K and Mn are mostly derived from seawater; and Fe, Cu, Zn and Ni are partly derived from magma. Based on the sulfur contents, trace and rare earth element compositions, and local environment, we suggest that the growth of the native sulfur ball is significantly slower than that of native sulfur chimneys, which results in the relatively higher contents of trace and rare earth element contents in the native sulfur ball than in the native sulfur chimneys from the Kueishantao hydrothermal field. Finally, we suggest a “glue pudding” growth model for understanding the origin of the native sulfur ball in the Kueishantao hydrothermal field, whereby the native sulfur ball forms from a mixture of oxygenated seawater and acidic, low-temperature hydrothermal fluid with H
2S and SO
2 gases, and is subsequently shaped by tidal and/or bottom currents.
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