The Arctic Ocean has turned from a perennial ice‐covered ocean into a seasonally ice‐free ocean in recent decades. Such a shift in the air‐ice‐sea interface has resulted in substantial changes in the ...Arctic carbon cycle and related biogeochemical processes. To quantitatively evaluate how the oceanic CO2 sink responds to rapid sea ice loss and to provide a mechanistic explanation, here we examined the air‐sea CO2 flux and the regional CO2 sink in the western Arctic Ocean from 1994 to 2019 by two complementary approaches: observation‐based estimation and a data‐driven box model evaluation. The pCO2 observations and model results showed that summer CO2 uptake significantly increased by about 1.4 ± 0.6 Tg C decade−1 in the Chukchi Sea, primarily due to a longer ice‐free period, a larger open area, and an increased primary production. However, no statistically significant increase in CO2 sink was found in the Canada Basin and the Beaufort Sea based on both observations and modeled results. The reduced sea ice coverage in summer in the Canada Basin and the enhanced wind speed in the Beaufort Sea potentially promoted CO2 uptake, which was, however, counteracted by a rapidly decreased air‐sea pCO2 gradient therein. Therefore, the current and future Arctic Ocean CO2 uptake trends cannot be sufficiently reflected by the air‐sea pCO2 gradient alone because of the sea ice variations and other environmental factors.
Key Points
Both observations and model results conclude that summertime CO2 sink increased significantly by 1.4 ± 0.6 Tg C decade−1 in the Chukchi Sea
Model results suggest that increased CO2 sink in the Chukchi Sea is driven by the reduced sea ice and increased primary production
Both observations and model results suggest no significant trend of CO2 sink in the Beaufort Sea and the Canada Basin between 1994 and 2019
While the effects of the Southern Annular Mode (SAM), a dominant climate variability mode in the Southern Ocean, on ocean acidification have been examined using models, no consensus has been reached. ...Using observational data from south of Tasmania, we show that during a period with positive SAM trends, surface water pH and aragonite saturation state at 60°-55° S (Antarctic Zone) decrease in austral summer at rates faster than those predicted from atmospheric CO
increase alone, whereas an opposite pattern is observed at 50°-45° S (Subantarctic Zone). Together with other processes, the enhanced acidification at 60°-55° S may be attributed to increased westerly winds that bring in more "acidified" waters from the higher latitudes via enhanced meridional Ekman transport and from the subsurface via increased vertical mixing. Our observations support climatic modulation of ocean acidification superimposed on the effect of increasing atmospheric CO
.
Seed weight is usually associated with seed size and is one of the important agronomic traits that determine yield. Understanding of seed weight control is limited, especially in soybean plants. Here ...we show that Glycine max JASMONATE‐ZIM DOMAIN 3 (GmJAZ3), a gene identified through gene co‐expression network analysis, regulates seed‐related traits in soybean. Overexpression of GmJAZ3 promotes seed size/weight and other organ sizes in stable transgenic soybean plants likely by increasing cell proliferation. GmJAZ3 interacted with both G. max RESPONSE REGULATOR 18a (GmRR18a) and GmMYC2a to inhibit their transcriptional activation of cytokinin oxidase gene G. max CYTOKININ OXIDASE 3‐4 (GmCKX3‐4), which usually affects seed traits. Meanwhile, the GmRR18a binds to the promoter of GmMYC2a and activates GmMYC2a gene expression. In GmJAZ3‐overexpressing soybean seeds, the protein contents were increased while the fatty acid contents were reduced compared to those in the control seeds, indicating that the GmJAZ3 affects seed size/weight and compositions. Natural variation in JAZ3 promoter region was further analyzed and Hap3 promoter correlates with higher promoter activity, higher gene expression and higher seed weight. The Hap3 promoter may be selected and fixed during soybean domestication. JAZ3 orthologs from other plants/crops may also control seed size and weight. Taken together, our study reveals a novel molecular module GmJAZ3‐GmRR18a/GmMYC2a‐GmCKXs for seed size and weight control, providing promising targets during soybean molecular breeding for better seed traits.
The soybean jasmonate ZIM doman (JAZ) protein GmJAZ3 regulates seed traits by orchestrating jasmonate and cytokinin signaling. JAZ3 was domesticated in soybean and this gene family shares conserved functions throughout monocots and dicots.
Rising seawater temperature and ocean acidification threaten the survival of coral reefs. The relationship between coral physiology and its microbiome may reveal why some corals are more resilient to ...these global change conditions. Here, we conducted the first experiment to simultaneously investigate changes in the coral microbiome and coral physiology in response to the dual stress of elevated seawater temperature and ocean acidification expected by the end of this century. Two species of corals, Acropora millepora containing the thermally sensitive endosymbiont C21a and Turbinaria reniformis containing the thermally tolerant endosymbiont Symbiodinium trenchi, were exposed to control (26.5°C and pCO2 of 364 μatm) and treatment (29.0°C and pCO2 of 750 μatm) conditions for 24 days, after which we measured the microbial community composition. These microbial findings were interpreted within the context of previously published physiological measurements from the exact same corals in this study (calcification, organic carbon flux, ratio of photosynthesis to respiration, photosystem II maximal efficiency, total lipids, soluble animal protein, soluble animal carbohydrates, soluble algal protein, soluble algal carbohydrate, biomass, endosymbiotic algal density, and chlorophyll a). Overall, dually stressed A. millepora had reduced microbial diversity, experienced large changes in microbial community composition, and experienced dramatic physiological declines in calcification, photosystem II maximal efficiency, and algal carbohydrates. In contrast, the dually stressed coral T. reniformis experienced a stable and more diverse microbiome community with minimal physiological decline, coupled with very high total energy reserves and particulate organic carbon release rates. Thus, the microbiome changed and microbial diversity decreased in the physiologically sensitive coral with the thermally sensitive endosymbiotic algae but not in the physiologically tolerant coral with the thermally tolerant endosymbiont. Our results confirm recent findings that temperature-stress tolerant corals have a more stable microbiome, and demonstrate for the first time that this is also the case under the dual stresses of ocean warming and acidification. We propose that coral with a stable microbiome are also more physiologically resilient and thus more likely to persist in the future, and shape the coral species diversity of future reef ecosystems.
A
bstract
With updated experimental data and improved theoretical calculations, several significant deviations are being observed between the Standard Model predictions and the experimental ...measurements of the branching ratios of
B
¯
s
0
→
D
s
∗
+
L
−
decays, where
L
is a light meson from the set {
π
,
ρ
,
K
(∗)
}. Especially for the two channels
B
¯
0
→
D
+
K
−
and
B
¯
s
0
→
D
s
+
π
−
, both of which are free of the weak annihilation contribution, the deviations observed can even reach 4–5
σ
. Here we exploit possible new-physics effects in these class-I non-leptonic
B
-meson decays within the framework of QCD factorization. Firstly, we perform a model-independent analysis of the effects from twenty linearly independent four-quark operators that can contribute, either directly or through operator mixing, to the quark-level
b →
c
u
¯
d
s
transitions. It is found that, under the combined constraints from the current experimental data, the deviations observed could be well explained at the 1
σ
level by the new-physics four-quark operators with
γ
μ
(1
− γ
5
) ⨂
γ
μ
(1
− γ
5
) structure, and also at the 2
σ
level by the operators with (1 +
γ
5
) ⨂ (1
− γ
5
) and (1 +
γ
5
) ⨂ (1 +
γ
5
) structures. However, the new-physics four-quark operators with other Dirac structures fail to provide a consistent interpretation, even at the 2
σ
level. Then, as two specific examples of model-dependent considerations, we discuss the case where the new-physics four-quark operators are generated by either a colorless charged gauge boson or a colorless charged scalar, with their masses fixed both at the 1 TeV. Constraints on the effective coefficients describing the couplings of these mediators to the relevant quarks are obtained by fitting to the current experimental data.
Background A sequenced house dust mite (HDM) genome would advance our understanding of HDM allergens, a common cause of human allergies. Objective We sought to produce an annotated Dermatophagoides ...farinae draft genome and develop a combined genomic-transcriptomic-proteomic approach for elucidation of HDM allergens. Methods A D farinae draft genome and transcriptome were assembled with high-throughput sequencing, accommodating microbiome sequences. The allergen gene structures were validated by means of Sanger sequencing. The mite's microbiome composition was determined, and the predominant genus was validated immunohistochemically. The allergenicity of a ubiquinol-cytochrome c reductase binding protein homologue was evaluated with immunoblotting, immunosorbent assays, and skin prick tests. Results The full gene structures of 20 canonical allergens and 7 noncanonical allergen homologues were produced. A novel major allergen, ubiquinol-cytochrome c reductase binding protein–like protein, was found and designated Der f 24. All 40 sera samples from patients with mite allergy had IgE antibodies against rDer f 24. Of 10 patients tested, 5 had positive skin reactions. The predominant bacterial genus among 100 identified species was Enterobacter (63.4%). An intron was found in the 13.8-kDa D farinae bacteriolytic enzyme gene, indicating that it is of HDM origin. The Kyoto Encyclopedia of Genes and Genomes pathway analysis revealed a phototransduction pathway in D farinae , as well as thiamine and amino acid synthesis pathways, which is suggestive of an endosymbiotic relationship between D farinae and its microbiome. Conclusion An HDM genome draft produced from genomic, transcriptomic, and proteomic experiments revealed allergen genes and a diverse endosymbiotic microbiome, providing a tool for further identification and characterization of HDM allergens and development of diagnostics and immunotherapeutic vaccines.
The efficient exploitation and utilization of low‐cost and biomass‐derived carbon materials will play an active role in developing sustainable energy storage systems. However, the difficult ...morphology control and incomplete activation limits their pervasive application in electrochemical energy storage. Inspired by the famous Chinese folk handicraft of sugar‐figure blowing, biomass‐derived carbon aerogels (GCA) with 2 D graphene‐like thin nanosheets were fabricated by a simple chemical blowing strategy from a viscous agaric solution obtained through hydrothermal treatment of agaric. A chemical blowing agent (NH4Cl) was used to effectively exfoliate the bulk biomass‐derived carbon flake into 2 D graphene‐like nanosheets, which resulted in a highly porous structure and high specific area (2200 m2 g−1) after the activation process. As a result, a high specific capacitance of 340 F g−1 at 3 A g−1 and a high specific energy of 25.5 Wh kg−1 at a power density of 2 kW kg−1 was obtained for the GCA electrode, which can be attributed to the abundant electrochemically active surfaces, short ion transport paths, and effective electrolyte infiltration.. This work demonstrates an effective and low‐cost strategy to prepare hierarchical and well‐organized porous biomass carbon materials with graphene‐like nanosheets for high‐performance supercapacitors.
Get blown away: A facile chemical blowing strategy inspired by sugar‐figure blowing—a Chinese folk handicraft—is used to fabricate a biomass‐derived carbon aerogel with graphene‐like nanosheet structures for high‐performance supercapacitors.
The South Atlantic Ocean is an important region for anthropogenic CO2 (Canth) uptake and storage in the world ocean, yet is less studied. Here, after an extensive sensitivity test and method ...comparison, we applied an extended multiple linear regression method with six characteristic water masses to estimate Canth change or increase (ΔCanth) between 1980s and 2010s in the South Atlantic Ocean using two meridional transects (A16S and A13.5) and one zonal transect (A10). Over a period of about 25 years, the basin‐wide ΔCanth was 3.86 ± 0.14 Pg C decade−1. The two basins flanking the Mid‐Atlantic Ridge had different meridional patterns of ΔCanth, yielding an average depth‐integrated ΔCanth in the top 2000 m of 0.91 ± 0.25 mol m−2 yr−1 along A16S on the west and 0.57 ± 0.22 mol m−2 yr−1 along A13.5 on the east. The west‐east basin ΔCanth contrasts were most prominent in the tropical region (0–20°S) in the Surface Water (SW), approximately from equator to 35°S in the Subantarctic Mode Water (Subantarctic Mode Water (SAMW)), and all latitudes in the Antarctic Intermediate Water (AAIW). Less ΔCanth in the eastern basin than the western basin was caused by weaker ventilation driven by SAMW and AAIW formation and subduction and stronger Antarctic Bottom Water (AABW) formation in the former than the latter. In addition to the spatial heterogeneity, Canth increase rates accelerated from the 1990s to the 2000s, consistent with the overall increase in air‐sea CO2 exchange in the South Atlantic Ocean.
Key Points
Between the 1980s and 2010s, the uptake rate of CO2 in the South Atlantic Ocean was 3.86 ± 0.14 Pg C decade‐1
The anthropogenic CO2 absorbed by the basin west of the Mid‐Atlantic Ridge is about three times that of the eastern basin
The lower uptake in the eastern basin is attributed to lower ventilation rates
A high‐resolution mooring record from the Changjiang River plume (45‐m depth) is used to investigate how air‐sea CO2 flux responds to typhoon in the productive plume. With strong wind, surface ...partial pressure of carbon dioxide (pCO2) increased sharply from 369 to 606 μatm due to entrainment of high‐CO2 subsurface water. Though it was followed by pCO2 decrease of 250 μatm and Chl a increase days after the typhoon, the typhoon caused a net CO2 efflux overall. The maximum CO2 efflux (+111.6 mmol·m−2·day−1) is much greater than that under non‐typhoon condition (−2.3 to −11.7 mmol·m−2·day−1). Based on historical typhoon records, we estimate typhoon‐induced CO2 efflux to be +0.27 Tg C/year, which can cancel 18% of summer CO2 influx in the East China Sea shelf. It may likely occur in other coastal waters. Ignoring such contribution may induce large bias in estimating regional air‐sea CO2 flux.
Plain Language Summary
Air‐sea CO2 flux estimations in shelf waters are improving in recent decades but still have large uncertainties. Short‐term events, such as tropical cyclones, could have significant influences in air‐sea CO2 flux estimations. In addition, recent climate models suggest tropical cyclones may become more intense over the coming century. We know little about how they influence regional air‐sea CO2 flux. Here, we present a high‐resolution mooring record from the Changjiang River plume to investigate how air‐sea CO2 flux responds to typhoon. In our record, surface partial pressure of carbon dioxide (pCO2) increased sharply from 369 to 606 μatm due to entrainment of high‐CO2 subsurface water. Though it was followed by pCO2 decrease and Chl a increase days after the typhoon, the typhoon caused a net CO2 efflux overall. The typhoon transferred CO2 from surface waters to atmosphere at a maximum rate of 111.6 mmol·m−2·day−1. Based on historical typhoon records, we estimate typhoon‐induced CO2 efflux to be +0.27 Tg C/year, which can cancel out 18% of summer CO2 influx in the East China Sea shelf. It may likely occur in other coastal waters. Ignoring such contribution may induce large bias in estimating regional air‐sea CO2 flux.
Key Points
Sea surface pCO2 increased by 237 μatm within 3 days during vertical mixing; it decreased by 250 μatm days after the typhoon
Entrainment of high‐pCO2 and hypoxic bottom water by typhoon caused CO2 efflux of +111.6 mmol·m−2·day−1 (CO2 sink under non‐typhoon condition)
Typhoon‐induced CO2 efflux is +0.27 Tg C/year, which can cancel out 18% of summer CO2 influx over the East China Sea shelf
Recent studies suggest that the formation and motion of the North Pacific subtropical mode water (STMW) play an important role in oceanic uptake, transport and storage of anthropogenic CO2 (CANT). ...However, the variability of STMW acidification rate and its control mechanisms remain unclear. Here we show that the STMW acidification rate during 2005–2020 is about two times of that during 1993–2005, which is due to the cooling‐driven enhanced CANT accumulation in the formation waters in the recent period. The rapid rates of CANT accumulation and acidification are consistently observed in the entire region across 137°–149°E regulated by STMW transport. Moreover, the tracer‐based (Δ14C and δ13C) analyses also indicate that the accelerated accumulation of CANT could be traced back to the surface formation waters via STMW formation. The vertical and horizontal consistencies imply the memory function of mode waters in retaining the anthropogenic carbon fingerprint during its formation and transport.
Plain Language Summary
The North Pacific subtropical mode water (STMW) is a vertically homogeneous thermocline water mass, occupying the entire subtropical western North Pacific and playing an important role in climate variability and material cycles. Using our new data and the integrated global data set within the STMW, we evaluated the decadal variability of ocean acidification in the STMW during 1993–2020. Results showed that the rate of STMW acidification during 2005–2020 was approximately 2 times of that during 1993–2005. We attributed the rapid acidification to the cooling‐induced acceleration of anthropogenic CO2 accumulation during 2005–2020, which could be traced back to the surface waters at the origin of the STMW. We therefore highlight that the memory function of mode waters could retain the anthropogenic carbon signal across annual to decadal timescales.
Key Points
The decline rates of pH and Ωarag in the North Pacific subtropical mode water (STMW) during 2005–2020 are ∼2 times of that during 1993–2005
The faster STMW acidification is attributed to the accelerated accumulation of anthropogenic CO2 (CANT) in the formation waters
The rapid rates of CANT accumulation and acidification are consistently observed across the 137°–149°E regulated by STMW transport
PDF
