Regenerated SERS substrate based on Ag/AuNPs-TiO2-oxidized carbon cloth for detection of imidacloprid.

Imidacloprid (IMI) are widely used in modern tea industry for pest control, but IMI residues pose a great threat to human health. Herein, we propose a regeneration metal-semiconductor SERS substrate for IMI detection. We fabricated the SERS sensor through the in-situ growth of a nano-heterostructure incorporating a semiconductor (TiO2) and plasmonic metals (Au, Ag) on oxidized carbon cloth (OCC). Leveraging the high-density hot spots, the formed Ag/AuNPs-TiO2-OCC substrate exhibits higher enhancement factors (1.92 × 108) and uniformity (RSD = 7.68%). As for the detection of IMI on the substrate, the limit of detection was lowered to 4.1 × 10-6 µg/mL. With a hydrophobic structure, the Ag/AuNPs-TiO2-OCC possessed excellent self-cleaning performance addressing the limitation of single-use associated with traditional SERS substrates, as well as the degradation capability of the substrate under ultraviolet (UV) light. Accordingly, Ag/AuNPs-TiO2-OCC showcases outstanding SERS sensing and regenerating properties, making it poised for extensive application in the field of food safety assurance.

Antibacterial properties of hexanal-chitosan nanoemulsion against Vibrio parahaemolyticus and its application in shelled shrimp preservation at 4 °C.

Vibrio parahaemolyticus has been considered as the leading pathogen associated with seafood-borne disease. Hexanal possesses antibacterial property but the hydrophobicity and volatility limit its application. The purpose of this study was to prepare hexanal-chitosan nanoemulsion (HCN), investigate its antibacterial ability against V. parahaemolyticus, and examine the combination of HCN with sodium alginate coating on the quality attributes of shrimp during cold storage. The mean droplet size of HCN fabricated by ultrasonic emulsification was 91.28 nm. HCN showed regular spherical shape and exhibited good centrifugation stability and storage stability at 4 °C. HCN exerted anti-V. parahaemolyticus effect with the minimum inhibitory concentration and minimal bactericidal concentration of both 5 mg/mL. Furthermore, HCN induced morphological changes and destroyed bacterial membrane, resulting in cell death. The results of preservation test showed that HCN alone and its combination with sodium alginate coating effectively retarded the quality deterioration and microbial spoilage of shelled shrimps during refrigerated storage. Comparatively, the combination treatment exhibited better preservation effect. The present study suggested that HCN prepared by ultrasonic emulsification is an effective alternative to control V. parahaemolyticus contamination in seafood and also shows great application potential in the quality maintaining of seafood during cold storage.

Hypoglycemic effect and intestinal transport of phenolics-rich extract from digested mulberry leaves in Caco-2/insulin-resistant HepG2 co-culture model.

Phenolics of mulberry (Morus alba L.) leaves (MLs) have potential anti-diabetic effects, but they may be chemically modified during gastrointestinal digestion so affect their biological activity. In this study, an in vitro digestion model coupled with Caco-2 monolayer and Caco-2/insulin-resistant HepG2 coculture model were used to study the transport and hypoglycemic effects of phenolics in raw MLs (U-MLs) and solid-fermented MLs (F-MLs). The results of LC-MS/MS analysis showed that the Papp (apparent permeability coefficient, 10-6cm/s) of phenolics in digested MLs ranged from 0.002 ± 0.00 (quercetin 3-O-glucoside) to 60.19 ± 0.67 (ferulic acid), indicating higher phenolic acids absorbability and poor flavonoids absorbability. The Papp values of phenolic extracts of F-MLs in Caco-2 monolayer were significantly higher (p > 0.05) than that of U-MLs. Digested phenolic extracts inhibited the activities of sucrase (60.13 ± 2.03 %) and maltase (82.35 ± 0.78 %) and decreased 9.28 ± 0.84 % of glucose uptake in Caco-2 monolayer. Furthermore, a decrease in the mRNA expression of glucose transporters SGLT1 (0.64 ± 0.18), GLUT2 (0.14 ± 0.02) and the sucrase-isomaltase (0.59 ± 0.00) was observed. In Caco-2/insulin-resistant HepG2 co-culture model, phenolic extracts regulated glucose metabolism by up-regulating the mRNA expressions of IRS1 (9.32-fold), Akt (17.07-fold) and GYS2 (1.5-fold), and down-regulating the GSK-3ß (0.22-fold), PEPCK (0.49-fold) and FOXO1 (0.10-fold) mRNA levels. Both U-MLs and F-MLs could improve glucose metabolism, and the partial least squares (PLS) analysis showed that luteoforol and p-coumaric acid were the primary phenolics that strongly correlated with the hypoglycemic ability of MLs. Results suggested that phenolics of MLs can be used as dietary supplements to regulate glucose metabolism.

The bioaccessibility, bioavailability, bioactivity, and prebiotic effects of phenolic compounds from raw and solid-fermented mulberry leaves during in vitro digestion and colonic fermentation.

The bioaccessibility and bioactivity of phenolic compounds in mulberry leaves (MLs) relate to the digestion process. This study was aimed at investigating the release of phenolic compounds, as well as the potential bioactivities of raw MLs (UF-MLs) and solid-fermented MLs (F-MLs) during in vitro digestion and colonic fermentation. Antioxidant activities and phenolic compounds released in the digested extracts are shown in decreasing order of location: intestinal > oral > gastric. The bioavailability of total phenolics and flavonoids in F-MLs were 10.14 ± 1.81 % and 6.66 ± 0.55 %, respectively. There was no significant difference in the inhibitory activity of α-glucosidase during gastrointestinal digestion. For colonic fermentation, the highest free radical-scavenging ability of DPPH and ABTS was found at 24 h and 48 h, respectively. The release of phenolic compounds was not significantly different after 48 h of colonic fermentation. LC-MS/MS showed that liquiritigenin, apigenin, chlorogenic acid, and ferulic acid were the major compounds released in the small intestine digestion, and valerenic acid was the primary colonic metabolite. 16S rDNA showed that UF-MLs promoted the growth of Bifidobacterium and F-MLs lowered the Firmicutes-to-Bacteroidetes ratio. Furthermore, F-MLs increased the concentration of acetic acids (25.75 ± 0.86 mM) after 24 h of colonic fermentation. The results of this study indicated that F-MLs exhibit relatively higher phenolic bioaccessibility, antioxidant activities, and SCFA production and are a promising candidate as a health food supplement.

Influence of encapsulated Lactobacillus plantarum and eugenol on the physicochemical properties and microbial community of fresh-cut apples.

This study aimed to evaluate the application of encapsulated L. plantarum and eugenol as potential biocontrol agents in sliced apples. The combined encapsulated L. plantarum and eugenol treatment was more effective than separate encapsulated L. plantarum and eugenol treatments, with regards to browning inhibition and consumers panel test. The application of encapsulated L. plantarum and eugenol reduced the decline of the physicochemical qualities of the samples, and improved the ability of antioxidant enzymes to scavenge reactive oxygen species. Furthermore, reductions in the growth of L. plantarum of only 1.72 log CFU/g were observed after 15 days of storage at 4 °C for samples treated with encapsulated L. plantarum and eugenol. Results suggest the combined encapsulated L. plantarum and eugenol appears to be a promising method to protect fresh-cut apples from food-borne pathogens while maintaining the visual appearance.

Recent developments in antifungal lactic acid bacteria: Application, screening methods, separation, purification of antifungal compounds and antifungal mechanisms.

Fungal contamination of food, which causes large economic losses and public health problems, is a global concern. Chemical methods are typically used in the food industry to inhibit the growth of spoilage fungus, but there are several drawbacks of chemical methods. Thus, the development of consumer-friendly and ecologically sustainable biological preservation technology has become a hot spot in food research. As a natural biological control agent, lactic acid bacteria (LAB) is a good choice in food preservation due to its antifungal properties. In order to screen and identify new antifungal LAB and antifungal compounds, this review compares three screening methods (overlay method, agar diffusion method, and microplate inhibition method) of antifungal LAB and summarizes the separation and purification techniques of antifungal compounds. A discussion of the effects of LAB, media, temperature, pH, and incubation period on the antifungal activity of LAB to highlight the antifungal properties of LAB for future studies then follows. Additionally, the antifungal mechanism of LAB is elucidated from three aspects: 1) LAB cells, 2) antifungal compounds, and 3) co-cultivation. Finally, research regarding antifungal LAB in food preservation (fruits, vegetables, grain cereals, bakery products, and dairy products) is summarized, which demonstrates the potential application value of LAB in food.

Enrichment and Distribution of Selenium in Pediococcus acidilactici MRS-7: Impact on Its Biochemical Composition, Microstructure, and Gastrointestinal Survival.

Lactic acid bacteria can convert selenium (Se) from inorganic to organic and elemental forms, but the distribution and existence form of organic Se in the bacteria are not clear after Se enrichment, and the effects of selenization on the growth and nutritional value of strains also need to be studied. In this study, Pediococcus acidilactici MRS-7 could absorb up to 67% of inorganic Se and convert most of it into organic Se; about 75% of organic Se was selenoprotein, 2.7% was Se-polysaccharide, and 4.6% was Se-nucleic acid. Additionally, Se-enriched treatment increased the levels of amino acids and essential elements in P. acidilactici MRS-7. Finally, after Se enrichment, Se nanoparticles (SeNPs) were found on the surface of P. acidilactici MRS-7, but they had no harmful effect on its morphology, and its survival during gastrointestinal digestion was not affected, indicating that SeP has potential probiotic value in the food industry.

Potential protective mechanism of Tibetan kefir underlying gut-derived liver injury induced by ochratoxin A.

Tibetan kefir (TK) is a good source of probiotics and has antioxidative, anti-inflammatory, and gut microbiota-regulating properties. Ochratoxin A (OTA) causes liver injury through the gut microbiota. It is unclear whether TK has differential effects on the gut-liver axis and whether these effects can alleviate liver injury induced by OTA. Herein, we investigated the hepatoprotective effect of TK in OTA-fed mice and its underlying mechanisms in the context of the gut. The results indicate that microorganisms in TK bound to OTA and decreased its gastrointestinal absorption. TK improved the intestinal barriers, and suppressed oxidative stress and inflammatory responses. Moreover, TK supplementation alleviated the gut microbiota dysbiosis by enriching beneficial microbiota such as Akkermansia and Lachnospiraceae UCG-006, and reducing harmful bacteria. Importantly, TK supplementation reversed the liver injury by reducing gut leakage of Bacteroides and lipopolysaccharides. Furthermore, untargeted metabolomics revealed that TK reversed the perturbation of metabolites involved in glycerophospholipid and bile acid metabolism, and regulated metabolites that are pertinent to the citrate cycle and tryptophan metabolism. TK also increased the production of short-chain fatty acids and anti-inflammatory metabolites. These data are consistent with the protective effects of TK against OTA-induced liver injury by maintaining the intestinal barrier and modulating the gut microbiota and metabolites. These findings will facilitate therapeutic interventions for mycotoxicosis.

Label-free fluorescence aptasensor for the detection of patulin using target-induced DNA gates and TCPP/BDC-NH2 mixed ligands functionalized Zr-MOF systems.

Patulin (PAT) is an unsaturated lactone mycotoxin primarily produced by Penicillium expansum and Aspergillus clavatus. Given the potential health risks and economic losses associated with PAT, the rapid detection of PAT using fluorescent aptasensors is of significant importance in evaluating food safety. However, it easily increases the cost and complexity caused by signal labeling. We combined TCPP/BDC-NH2 mixed ligands functionalized Zr metal-organic frameworks (Zr-MOFmix) and terminated three-stranded DNA gates (ttsDNA gates) to fabricate a label-free fluorescent aptasensor for PAT detection. The Zr-MOFmix system was synthesized via a one-pot strategy and could be used to address the problem of pore size limitation and increase the loading amounts of dyes. TtsDNA gate was integrated into the Zr-MOFmix system to control the release of dyes, exhibiting a high signal-to-background ratio. The single-stranded aptamer region in ttsDNA gate situated away from the surface of the Zr-MOFmix, resulting in a natural release of dyes in the absence of PAT. While binding to PAT resulted in target-induced conformational changes that helped form the hairpin structure of the aptamer. This structure hindered the release of dyes from the pores of Zr-MOFmix, thus reducing the fluorescence signals intensity. The stimuli-responsive DNA-gated material provides a platform for PAT analysis under conditions of a low limit of detection (0.871 pg/mL). Furthermore, the excellent specificity and anti-interference of the fluorescent aptasensor make the system suitable for the analysis of apple juice samples. This label-free strategy is cheaper and simper compared with labeled detection, especially for the development of multi-target-detection.

Protective effects of Tibetan kefir in mice with ochratoxin A-induced cecal injury.

Ochratoxin A (OTA) is reported to cause intestinal damage following ingestion of contaminated foods. Tibetan kefir (TK) is a fermented dairy product that possesses antioxidant, anti-inflammatory, and gut microbiota-regulating properties. However, it is not clear if TK can alleviate OTA-associated intestinal toxicity. Here, we investigated whether TK can prevent OTA-induced intestinal barrier disruption in mice. To this end, OTA-fed mice were treated with sterile water (control) or TK by oral gavage once daily, for 3 weeks. The histological changes of ceca, the expression of tight junction proteins and mucins, and the levels of oxidative stress, inflammatory response, and gut microbiota were then assessed. Results revealed that treatment with TK reversed OTA-driven histopathological changes in the ceca, and was associated with increased cecal mucin levels. TK administration to OTA-treated mice significantly elevated the expression levels of tight junction proteins (claudin-1, zonula occludens-1, and occludin). Additionally, TK supplementation suppressed OTA-induced oxidative stress and reduced inflammation via the NF-κB signaling pathway in the ceca. Moreover, TK supplementation depleted harmful bacteria (e.g., Turicibacter and Desulfovibrio), while supporting short-chain fatty acids (SCFAs)-producing bacteria (e.g., Lachnospiraceae, Blautia, and Ruminococcus), which maintained the SCFAs levels. Taken together, our findings indicate that TK may emerge as a viable dietary strategy to prevent intestinal toxicity-based injuries.

Selenium-Enriched Pediococcus acidilactici MRS-7 Alleviates Patulin-Induced Jejunum Injuries in Mice and Its Possible Mechanisms.

Patulin (PAT) is a common mycotoxin. Oral ingestion of PAT could damage the intestinal mucosa. Both selenium and probiotics can alleviate intestinal damage, but there are few reports on selenium-enriched probiotics. Here, we studied the protective effects of a new selenium-enriched Pediococcus acidilactici MRS-7 (SeP) on PAT-induced jejunum injuries in mice. Results show that PAT induced jejunum injuries such as loss of crypts, ulceration of the mucosa, and intestinal epithelial barrier function impairment. However, SeP could protect against PAT-induced jejunum injuries and significantly inhibit the reduction of goblet cell numbers. SeP could not only alleviate PAT-induced oxidative stress by decreasing malondialdehyde (MDA) and increasing superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH-Px) levels in the jejunum tissues but also alleviate the inflammatory response caused by PAT by reducing the levels of inflammatory factors (interleukin (IL)-6 snd IL-1ß and tumor necrosis factor-α (TNF-α)) in the serum and jejunum tissues. In addition, SeP also inhibited the expression of nuclear factor-κB (NF-κB) and Toll-like receptor 4 (TLR-4), increased the expression of tight junction proteins (occludin, ZO-1, and claudin-1), and increased the selenium content in the jejunum, thereby antagonizing the jejunum injuries caused by PAT exposure. Finally, SeP rebalanced the intestinal microbiota and improved probiotic abundance such as Turicibacter, Bifidobacterium, Ileibacterium, and Pediococcus in PAT-treated mice. These results support the possibility of SeP as a novel protective agent to mitigate the toxicity of PAT.

Selenium-containing tea polysaccharides ameliorate DSS-induced ulcerative colitis via enhancing the intestinal barrier and regulating the gut microbiota.

Both tea polysaccharides and selenium have certain remission potential for ulcerative colitis (UC), but few reports focused on natural selenium-containing tea polysaccharides. The purpose of this study was to isolate a selenium-containing tea polysaccharide (ASeTP) and determine its structure and effects on UC. Results showed that ASeTP was primarily composed of three purified, ß-pyranoside-linked, protein-binding polysaccharides (SeTP-1, SeTP-2, and SeTP-3) with SeOC, OSeO, and SeO linkages. Specifically, SeTP-1 was a neutral heteropolysaccharide principally composed of mannose, glucose, galactose, xylose, and arabinose, while SeTP-2 and SeTP-3 were acidic heteropolysaccharides due to the existence of glucuronic acid. ASeTP effectively alleviated the symptoms of weight loss, colon shortens, and disease activity index scores increase in dextran sodium sulfate (DSS)-induced colitis mice. ASeTP attenuated the histological damage and maintained the colonic mucosal barrier via up-regulating the expression of occludin, claudin-1, and zona occludens-1 (ZO-1). ASeTP suppressed the levels of pro-inflammatory cytokines and enhanced the antioxidant capacity of colon tissue. Besides, ASeTP beneficially increased the selenium content of the colon. Furthermore, ASeTP remodeled the gut microbiota by accelerating the proliferation of beneficial bacteria and inhibiting pathogenic microorganisms. Thus, ASeTP has the potential to be a functional food against colitis.

Relationships between optical backscattering, particulate organic carbon, and phytoplankton carbon in the oligotrophic South China Sea basin.

The particulate backscattering coefficient (bbp) provides effective proxies for particulate organic carbon (POC) and phytoplankton carbon (Cphy); however, their bio-optical relationships in the oligotrophic ocean are rarely reported. In this work, based on the in-situ synchronous optical and biogeochemical measurements in the oligotrophic South China Sea (SCS) basin, we refined the regional relationships between POC (and Cphy) and bbp and investigated the impacts of phytoplankton community compositions and size classes on the bbp variability. The observations showed that: 1) POC and Cphy exhibited good linear relationships with bbp; 2) the relationship between Cphy and POC could also be fitted in a linear function with a positive POC intercept, and the POC contributed by phytoplankton-covarying non-algal particles was nearly two-fold of Cphy; and 3) the POC-specific bbp (b*bp) was positively correlated with the fraction of the phytoplankton groups haptophytes (Type 8) and diatoms to total Chla, but negatively correlated with the fraction of pico-phytoplankton to Chla (fpico). These findings suggest that in oligotrophic waters, the variability of b*bp was mainly determined by the variability in the relative contribution of large phytoplankton with complex structures.

Aptamer-based thin film gold electrode modified with gold nanoparticles and carboxylated multi-walled carbon nanotubes for detecting oxytetracycline in chicken samples.

In this work, a disposable and portable aptasensor for the fast and sensitive detection of oxytetracycline (OTC) using gold nanoparticles (AuNPs)/carboxylated multi-walled carbon nanotubes (cMWCNTs)@thionine connecting complementary strand of aptamer (cDNA) as signal tags was constructed. The substrate electrode of the aptasensor was thin film gold electrode (TFGE), which have the advantages of portable and uniform performance. In the presence of OTC, OTC competed with cDNA to combine with aptamer. The bioconjugate (AuNPs/cMWCNTs/cDNA@thionine) was released from the TFGE. Thus, the electrochemical signal declined. Under optimized conditions, the aptasensor exhibited good stability, high selectivity and high sensitivity. Furthermore, the developed electrochemical aptamer-based TFGE had a wide dynamic range of 1 × 10-13-1 × 10-5 g mL-1 for target OTC with a low detection limit of 3.1 × 10-14 g mL-1 and was successfully used for the determination of OTC in chicken sample.

Previously unidentified Indonesian Throughflow pathways and freshening in the Indian Ocean during recent decades.

The Earth has experienced a global surface warming slowdown (GSWS) or so-called "global warming hiatus" since the end of the 20th century. The GSWS was marked by a La Niña-like decadal cooling in the Pacific Ocean that subsequently generated an increase in the transfer of Pacific waters into the Indian Ocean via the Indonesian Throughflow (ITF). How the Pacific water spreads through the interior of the Indian Ocean and the impact of these decadal ITF transport changes on the Indian Ocean water mass transformation and circulation remain largely unknown. Here, we analyze the thermohaline structures and current systems at different depths in the Indian Ocean prior to and during the GSWS period. Our study shows that the GSWS involved extensive changes to the Indo-Pacific ocean teleconnection system, characterized by subsurface warming and freshening in the Indian Ocean. A hitherto unknown Indian Ocean pathway of the ITF was discovered off Sumatra associated with prolonged northwestward flow within the South Java Current. Our analysis uncovers a direct linkage of enhanced ITF waters with the Agulhas Current in the Mozambique Channel from thermocline depths down to intermediate depths, that freshened the Indian Ocean. These changes in the Indian Ocean circulation and water mass characteristics impact climate variability through changing the sea surface temperature (SST) and precipitation patterns that can subsequently affect regional economies.

An amperometric zearalenone aptasensor based on signal amplification by using a composite prepared from porous platinum nanotubes, gold nanoparticles and thionine-labelled graphene oxide.

The authors constructed a voltammetric zearalenone (ZEN) aptasensor based on use of porous platinum nanotubes, gold nanoparticles (p-PtNTs/AuNPs) and thionine (Thi) labelled graphene oxide (GO). The p-PtNTs were synthesized in-situ based on tellurium nanowires as sacrificial templates. Subsequently, thiol-modified aptamers were self-assembled on the AuNPs that had been electrodeposited on the surface of the modified electrode. The presence of p-PtNTs on the electrode increases the loading with AuNPs and aptamers. It also warrants that the Thi-labelled GO can be assembled onto the aptamer via π interactions. In the presence of ZEN, it will be bound by the aptamer. The GO/Thi conjugate will be released from the aptamer, and this causes a decrease in Thi current. Under the optimal conditions and at a typical working potential of -0.22 V (vs. Ag/AgCl), the method has a linear range that covers the 0.5 pg·mL-1 to 0.5 µg·mL-1 ZEN concentraion range and a lower detection limit of 0.17 pg·mL-1. Graphical abstract Voltammetric zearalenone aptasensor based on use of porous platinum nanotubes/gold nanoparticles and thionine labelled graphene oxide was fabricated for the detection of zearalenone.

Warming in the Agulhas Region during the Global Surface Warming Acceleration and Slowdown.

The Agulhas Region gains more heat during the global surface warming slowdown than acceleration period. Yet, mechanisms that cause excessive heat accumulation in this region remain largely unknown. We investigate the underlying physical processes and examine their influence on ocean heat changes in the last three decades. Heave is found to drive the increasing ocean heat content in the last three decades whereas elevated heat accumulation rate in slowdown compared than acceleration period is mainly attributed to spice. During the acceleration period, pure heaving of Subtropical Mode Water induced by wind stress change and pure warming caused by heat flux, leading to a strong heave component and relatively weak spice, drive the increases in ocean heat content. During the slowdown period, increasing salinity strengthens the spice, resulting in a higher heat accumulation rate compared to the acceleration period.

Modifications of Au Nanoparticle-Functionalized Graphene for Sensitive Detection of Sulfanilamide.

In this paper, we present a simple and feasible electrochemical sensor based on Au nanoparticle-functionalized graphene for the determination of sulfanilamide. Au nanoparticles were deposited on graphene, which acted as a platform to prepare excellent nanocomposites. Attributed to the graphene's large surface area and the Au nanoparticles' strong conductivity, many sulfanilamide molecules were enriched on the sensor surface and the signal response became more sensitive. Under the optimal conditions, the electrochemical sensors could be used for the efficient detection of sulfanilamide. Good linearity was observed in the range of 0.1-1000 µmol·L-1 and the detection limit was 0.011 µmol·L-1. Most importantly, the Au nanoparticle-functionalized graphene-modified electrode could be successfully applied for the detection of sulfanilamide in animal meat, and exhibited good stability, acceptable recovery, and offered a promising platform for point-of-care detecting in real samples.

Decadal Western Pacific Warm Pool Variability: A Centroid and Heat Content Study.

We examine several characteristics of the Western Pacific Warm Pool (WP) in the past thirty years of mixed interannual variability and climate change. Our study presents the three-dimensional WP centroid (WPC) movement, WP heat content anomaly (HC) and WP volume (WPV) on interannual to decadal time scales. We show the statistically significant correlation between each parameter's interannual anomaly and the NINO 3, NINO 3.4, NINO 4, SOI, and PDO indices. The longitudinal component of the WPC is most strongly correlated with NINO 4 (R = 0.78). The depth component of the WPC has the highest correlation (R = -0.6) with NINO3.4. The WPV and NINO4 have an R-Value of -0.65. HC has the highest correlation with NINO3.4 (R = -0.52). During the study period of 1982-2014, the non-linear trends, derived from ensemble empirical mode decomposition (EEMD), show that the WPV, WP depth and HC have all increased. The WPV has increased by 14% since 1982 and the HC has increased from -1 × 108 J/m2 in 1993 to 10 × 108 J/m2 in 2014. While the largest variances in the latitudinal and longitudinal WPC locations are associated with annual and seasonal timescales, the largest variances in the WPV and HC are due to the multi-decadal non-linear trend.

The Subpolar North Atlantic Ocean Heat Content Variability and its Decomposition.

The Subpolar North Atlantic (SPNA) is one of the most important areas to global climate because its ocean heat content (OHC) is highly correlated with the Atlantic Meridional Overturning Circulation (AMOC), and its circulation strength affects the salt transport by the AMOC, which in turn feeds and sustains the strength of the AMOC. Moreover, the recent global surface warming "hiatus" may be attributed to the SPNA as one of the major planetary heat sinks. Although almost synchronized before 1996, the OHC has greater spatial disparities afterwards, which cannot be explained as driven by the North Atlantic Oscillation (NAO). Temperature decomposition reveals that the western SPNA OHC is mainly determined by the along isopycnal changes, while in the eastern SPNA along isopycnal changes and isopycnal undulation are both important. Further analysis indicates that heat flux dominates the western SPNA OHC, but in the eastern SPNA wind forcing affects the OHC significantly. It is worth noting that the along isopycnal OHC changes can also induce heaving, thus the observed heaving domination in global oceans cannot mask the extra heat in the ocean during the recent "hiatus".