Average SST Research Articles

Functional responses of a medium-ranging marine predator highlight the importance of frontal zones as foraging locations

The distribution of marine predators is linked to bio-physical processes that structure the spatio-temporal availability of prey species. Within shelf seas, tidal fronts are highly productive regions occurring at the interface between mixed and stratified waters. Fronts are predictable but dynamic features, with their timing and strength varying seasonally and annually. The availability of frontal habitats will also vary between animal populations depending on geographic location. Thus, understanding the associations between marine predators and frontal habitats across a range of environmental conditions will assist marine management and conservation. Here, we assessed functional responses of breeding black-legged kittiwakes Rissa tridactyla to environmental covariates related to tidal fronts (front strength, distance to fronts, sea surface temperature [SST] and surface chlorophyll concentration) from 10 UK colonies located throughout the North Sea. Kittiwakes showed a tendency to forage in areas of higher, but not maximal, front strength when such areas were available. Areas closer to fronts (<10 km) were selected when available, though we also observed increased usage of areas distant from fronts (30-50 km). Kittiwakes tended to forage in cooler, mixed waters, particularly as average SST rose. When average chlorophyll concentrations were low, habitat usage peaked in areas of higher chlorophyll. The results highlight the importance of frontal habitats and the dynamic, non-linear nature of seabird responses to habitat. Accounting for dynamic changes in habitat availability will play a key role in future conservation efforts, particularly as marine renewable installations and climate change may influence water stratification patterns.

Potential thermal constraints for sustainable industrial city: refined simulation and prediction of extreme urban heat island effect

Extreme urban heat islands (E-UHIs) have caused radical changes in urban climates. The lack of refined extreme thermal environment simulation models (ETESM) hinders research on the spatial evolution of E-UHI, which increases the uncertainty for managers to make sustainable decisions. Here, considering both the heating of industrial land and the heat transfer of surrounding facilities, a refined ETESM is constructed. Assuming four scenarios: maintain current trend (MtS), economically oriented scenario (EcS), environmentally oriented scenario (EnS), green transformation scenario (GtS), the future potential constraints of the E-UHI are simulated and predicted, thus determining the sustainable development decision in industrial city. The results indicate that there is significant spatial consistency between simulated temperature and actual temperature at both city scale (Pearson'r = 0.924, P<0.001) and industrial land scale (Pearson'r = 0.948, P<0.001). The average temperature under four scenarios shows: EcS>MtS>GtS>EnS. The average SST of EnS and GtS was 1.36℃ and 1.06℃ lower than that of MtS, respectively. Considering the dual constraints of environmental livability and economic sustainability, GtS is the best decision to achieve the sustainable development in industrial city. This simulation-driven study provides support for E-UHI mitigation and sustainable development of industrial city.

Analysis of Sea Surface Temperature and Chlorophyll-A and Its Relationship with Catch Results Flying Fish Eggs in the Waters of the Kei Islands

The Kei Islands water area is quite productive in fisheries management. Environmental characteristics and oceanographic factors in a body of water will determine the potential of fisheries resources in a water body, and influence fish movement patterns and the formation of fishing areas for flying fish eggs. This research aims to examine the distribution of sea surface temperature and chlorophyll-a concentrations and analyze the relationship between sea surface temperature and chlorophyll-a concentrations with catches of flying fish eggs. The research focused on the waters of the Kei Islands, Southeast Maluku, which is an area for catching flying fish eggs. The research data was studied in the period December 2014 – November 2017. SPL and Chlorophyll-a data were downloaded from Citra MODIS-Aqua, while data on flying fish egg production was obtained from PPN Tual. The research results show that the monthly average SST distribution is between 25.03-30.42ºC, and the monthly average of chlorophyll-a varies quite widely with a range of 0.05-3.09 mg/m3. The number of flying fish egg production fluctuates every year with a production range of 36.28-81.905 kg. The peak of catching flying fish eggs occurs in June-September (eastern season and transition season II). The results of the analysis show that the correlation between SST and chlorophyll-a variables has a very dominant influence on the abundance of flying fish eggs.

Responses of Satellite Chlorophyll-a to the Extreme Sea Surface Temperatures over the Arabian and Omani Gulf

Extreme events such as Marine Heat Waves (MHWs) and Low Chlorophyll-a (LChl-a) in the ocean have devastating impacts on the marine environment, particularly when they occur simultaneously (i.e., the compound of MHWs and LChl-a events). In this study, we investigate the spatiotemporal variability of MHWs and LChl-a events in the Arabian and Omani Gulf. For this purpose, we used satellite-based high-resolution observations of SST (0.05° × 0.05°; from 1982 to 2020) and chlorophyll-a concentration data (0.04° × 0.04°; from 1998 to 2020). Hourly air temperature, wind, and heat flux components from the European Centre for Medium-Range Weather Forecasts (ECMWF) reanalysis (ERA5) were used to explain the link between these extreme events and atmospheric forcings. Moreover, our results revealed that the annual frequency of MHW and LChl-a is related to the El Niño-Southern Oscillation (ENSO) and the Indian Ocean Dipole (IOD). The results revealed an average SST warming trend of about 0.44 ± 0.06 °C/decade and 0.32 ± 0.04 °C/decade for the Arabian Gulf (AG) and the Gulf of Oman (OG), respectively. This warming rate was accompanied by MHW frequency and duration trends of 0.97 events/decade and 2.3 days/decade, respectively, for the entire study region from 1982 to 2020. The highest annual MHW frequencies were recorded in 2010 (6 events) and 2020 (5 events) associated with LChl-a frequency values of 4 and 2, respectively. La Niña events in 1999, 2010, 2011, and 2020 were associated with higher frequencies of MHW and LChl-a. The positive phase of IOD coincides with high MHW frequency in 2018 and 2019. The longest compound MHW and LChl-a event with a duration of 42 days was recorded in 2020 at OG. This extreme compound event was associated with wind stress reduction. Our results provide initial insights into the spatiotemporal variability of the compound MHW and LChl-a events that occurred in the AG and OG.

Assessment of the stock status for greenland halibut (&lt;i&gt;Reinhardtius hippoglossoides matsuurae&lt;/i&gt;) in the Okhotsk Sea

State of the greenland halibut stock in the Sea of Okhotsk fishing zone is evaluated as overfished with a high probability of 97.5 % by the index of fishable biomass, and the overfishing continued in 2021. This conclusion is based on results of double filtering the posterior parameter estimates in the state-space generalized surplus production model JABBA (Just Another Bayesian Biomass Assessment), with additional tuning of the new model taking into account these results. The overfishing was not caused by significant changes of environmental parameters (average SST and EOF modes of SST were examined), but its main reason was the overestimated target harvest rate established for the Far East of Russia as 10 % of the total biomass or a half of natural annual mortality (20 %). This incorrect value of the rate was based on incorrect determination of age structure and terminal age for the halibut by the fish scale method. The new approach of the stock status evaluation with JABBA model is independent on the age data. It includes the additional filtering of the JABBA model result, its refinement with stringent tuning using the algorithm of No-U-Turn sampler, and checking additional parameters on hyperstability or hypersensitivity. The new reference point of the target harvest rate is between 2.5 and 5.4 % (95 % credible interval) of the total biomass, with a median of about 3.75 %. This new value is slightly higher than that one used by ICES for greenland halibut in the northeastern Atlantic (3.5 % for fishable biomass, its reduction to 2.5 % is discussed), but these values cannot be compared because of different habitat conditions and probably different growth rate of greenland halibut in the Okhotsk Sea and the Atlantic. Researches on the optimal level of greenland halibut exploitation should be continued; anyway, the new reference point of the target harvest rate has to be implemented immediately and to be used at least until correction of the age-length key for greenland halibut in the Okhotsk Sea. The input data and Stan code of the new model are presented in the annexes.

Distribution of Skipjack (Katsuwonus Pelamis) Fishing Areas using Purse Seine Fishing Equipment in WPP 573

Estimation of fishing grounds is one solution to facilitate time efficiency in fishing activities. Efforts are made to predict the fishing ground (fishing ground) through an approach to oceanographic physical conditions. The dynamics of skipjack fishing areas are influenced by oceanographic parameters such as sea surface temperature and chlorophyll-a concentration. Skipjack tuna (Katsuwonus pelamis) is the main type of fish caught in Indonesian waters. This study aims to analyze the dynamics of oceanographic conditions in the form of sea surface temperature and chlorophyll-a distribution, the relationship between skipjack fishing season and the dynamics of sea surface temperature distribution and chlorophyll-a distribution in WPP 573 waters 2016-2020 and predict skipjack fishing season.The catch results show that the average SST value obtained from the fishing grounds is 29.44 oC, the minimum value is 26.76 oC and the maximum value is 32.32 oC, while for the concentration of chlorophyll-a the average value obtained is 0.19 mg/ m3, the minimum value is 0.08 mg/m3 and the maximum value is 0.95 mg/m3. The average temperature and chlorophyll-a 2016-2020 that coincided with the high catch were 28.5oC and 0.23 mg/m3. The results of the MaxEnt model show that the evaluation of the model is in a good category, the percentage of SST contribution is higher than Chlorophyll-a, the probability index value for skipjack fish is around 0.5-0.8 and the results of the validation of fishing data are mostly widespread according to the results of the 2016-2020 MaxEnt model. The results also show that the east season, namely June, July and August, is a good fishing season for skipjack tuna, whereas skipjack catches decline in the west season, December, January and February.

Влияние эффекта глобального потепления на качественные характеристики популяции черноморского шпрота на Крымско-Кавказском шельфе Черного моря

The Black Sea sprat Sprattus sprattus phalericus (Risso) and temperature factor impact have been investigated. Statistical assessment of the long-term dynamics (1951–2019) of a relationship between the temperature factor and sprat mean weight in fishery catches used as a population quality characteristic has been performed. Pearson product-moment correlation and cross-correlation was evaluated, then data series was smoothed by the local polynomial regression and, finally, a linear model was fitted. The correlation test shows significant relationship between the temperature factor and sprat mean weight-at-age (mean weight in 3+ age group and SST in the port of Yalta resulted in r = -0.86, whereas average SST and average mean weight by age classes led to r = -0.74). The fitted linear model by smoothed data of average SST and average weight-at-age successfully passed diagnostics (R2 = 0.87, RSE = 0.34), with the equation: w = f(sst) = 22.23 - 1.263*sst. As a result, this study allows to emphasize the temperature factor as a main driver of the sprat fishery quality characteristics. The global warming effect, starting since the 1990’s has had a significant negative impact on the sprat population.

Studi Karakteristik Suhu Permukaan Laut (SPL) Di Perairan Selat Lombok Menggunakan Citra Satelit EOS Aqua MODIS

The Lombok Strait is a strait located between Lombok Island and Bali Island which connects the waters of the Bali Sea to the Indian Ocean, whose SST conditions vary with oceanographic-atmospheric conditions in the Indian Ocean and the Pacific Ocean. This research aims to determine the temporal and spatial SST in the North and South Lombok Strait. Therefore, this study divides the Lombok Strait area into two because of the influence of the Pacific Ocean and the Indian Ocean. The method used in this research is descriptive and statistical analysis. The highest average monthly SST in the northern and southern Lombok Strait occurred in April at 29.11 °C and the lowest in August at 26.82°C. For the average seasonal SST, the highest occurred at transition I of 28.86°C, and the lowest occurred in the eastern season at 27.39°C. The highest average annual SST occurred in 2010 at 28.83°C and the lowest occurred in 2018 at 27.69°C. The northern SST anomaly has the same fluctuation as ENSO with inversely proportional IOD. Southern SST anomaly has fluctuation which is inversely proportional to ENSO and IOD. The correlation between SST anomaly in the north and ENSO correlates 0.90 (very strong), while with IOD it correlates 0.12 (very low). The correlation between SST anomaly in the southern part and ENSO correlates -0.11 (very low), while with IOD it correlates -0.73 (strong)

Flood hydrometeorological situations associated with monsoon floods on the Par River in Western India

The objective of present work is to understand flood hydrometeorological situations associated with monsoon floods on the Par River, therefore, the analyses of synoptic conditions connected with large floods was carried out. This encompasses analysis of interannual rainfall variability and associated floods, analysis of storm tracts, investigation of normalized accumulated departure from mean (NADM) and evaluation of the relation between El Niño and monsoon rainfall. In order to accomplish above analyses, the annual rainfall data of the Par Basin have been obtained for 118 years from India Meteorological Department (IMD), Pune and Chennai. The annual maximum series (AMS)/stage data were procured for a gauging site namely Nanivahial for 45 years from Irrigation Department of Gujarat State, Ahmedabad. The results indicate that the interannual variability was characterized by increased frequency and magnitude of floods on the Par River primarily after 1930s. Majority of the large floods in the basin were connected with low pressure systems. It is observed that most of the floods were associated with positive departure from mean rainfall in the basin. The NADM graph shows epochal behaviour of high and low rainfall of the basin and floods. The analysis of El Niño and Southern Oscillation indicates that the probability of the occurrence of the floods in the Par Basin is high during the average SST index and majority of the floods in the basin have occurred during above normal conditions of rainfall. The present study can, therefore, prove to be a significant contribution towards the Par-Tapi-Narmada link project of the Government of Gujarat and water divergent projects of the Government of Maharashtra in association with Government of India.

Impacts of heat stress and storm events on the benthic communities of Kenting National Park (Taiwan).

Over the past few decades, extreme events—such as ocean warming, typhoons, and coral bleaching—have been increasing in intensity and frequency, threatening coral reefs from the physiological to ecosystem level. In the present study, the impacts of rising seawater temperatures, typhoons, and coral bleaching events on benthic communities were seasonally assessed over a 21 month-period, using photo-transects at 11 sites in Kenting National Park (KNP), Taiwan. Between August 2015 and April 2017, seven typhoon events were recorded and in situ seawater temperatures in KNP reached a maximum of 31.2 °C, as opposed to an average maximum SST of 28.8 °C (2007–2016). The state and response of benthic communities to these events were interpreted based on the environmental conditions of KNP. The repeated storms lowered the levels of thermal stress during the 2015–2016 El Niño event and may have mitigated its impact on the Taiwanese coral reefs. However, storm-induced local shifts from coral to macro-algae dominance were observed. Storms may mitigate the negative effects of heatwaves, but the mechanical damage induced by the storms may also decrease the structural complexity of reefs and their associated diversity. Eventually, despite reef persistence, the composition and function of remnant communities may profoundly diverge from those in regions with less active storms.

Classification and analysis of sea‐effect snowbands for Danube Sea area in Black Sea

AbstractIn this study, for the Danube Sea Area (Danube Region—western part of the Black Sea), the structure of the sea effect snow (SES) bands, meteorological conditions in which SES bands occurred, and SES band types are analysed for the period 2009–2018. In the 10‐year period, snowy times were determined using aviation reports published by four airports within the borders of the Marmara Region. SES events and SES bands were determined by examining the several satellite images (Channel 9‐IR, Natural Colour‐RGB, Airmass‐RGB, Channel 6‐VW) obtained from the Spinning‐Enhanced Visible and Infrared Imager (SEVIRI) device on MSG‐2 (Meteosat‐9) and MSG‐3 (Meteosat‐10) satellites. The Danube Region is divided into six sub‐regions. Five different types of SES bands were analysed separately for each sub‐region. Some meteorological conditions that are known to play an important role in the formation of SES bands (presence, thickness and level of the inversion layer; wind structure in the upper levels over the sea; sea surface temperature—SST) were analysed for the snowy times with sea‐effect. According to the preliminary results; a total of 186 days were found to be snowy, 75 days of these snowy days occurred with sea‐effect, and SES bands were seen in 8 days but did not cause snowfall in the Marmara Region. Type‐2 (T‐2) band was the most common band type (85%) over the Danube Region. The inversion layer(s) were observed between the level of 850–700 hPa in 52 days of 75 snowy days with sea effect. The majority of the direction of the upper‐level winds (at 850 and 700 hPa) was found to be northern (North‐N, Northwest‐NW, Northeast‐NE). The lowest average SST value (6.02°C) observed in the sub‐region ‘A’ and the highest average SST value (8.66°C) was observed in the sub‐region ‘F’.

Predicting habitat use by the Argentine hake Merluccius hubbsi in a warmer world: inferences from the Middle Holocene.

Fish skeletal remains recovered from two archaeological sites dated in the Middle Holocene of Tierra del Fuego (Argentina) were analysed to describe habitat use patterns by hake in the past and predict changes in a warmer world. Mitochondrial DNA was successfully extracted and amplified from 42 out of 45 first vertebra from ancient hake and phylogenetic analysis assigned all haplotypes to Argentine hake (Merluccius hubbsi). According to osteometry, the Argentine hake recovered from the archaeological site were likely adults ranging 37.2-58.1cm in standard length. C and N stable isotope analysis showed that currently Argentine hake use foraging grounds deeper than those of Patagonian blenny and pink cusk-eel. Argentine hake, however, had a much broader isotopic niche during the Middle Holocene, when a large part of the population foraged much shallower than contemporary pink cusk-eel. The overall evidence suggests the presence of large numbers of Argentine hake onshore Tierra del Fuego during the Middle Holocene, which allowed exploitation by hunter-gatherer-fisher groups devoid of fishing technology. Interestingly, average SST off Tierra del Fuego during the Middle Holocene was higher than currently (11°C vs 7°C) and matched SST in the current southernmost onshore spawning aggregations, at latitude 47°S. This indicates that increasing SST resulting from global warming will likely result into an increased abundance of adult Argentine hake onshore Tierra del Fuego, as during the Middle Holocene. Furthermore, stable isotope ratios from mollusc shells confirmed a much higher marine primary productivity during the Middle Holocene off Tierra del Fuego.

Structure and environmental drivers of phytoplanktonic resting stage assemblages in the central Mediterranean Sea

Phytoplankton species can produce resting stages that persist in the sediment over long periods and accomplish important ecological functions. With the aim of investigating the phytoplankton assemblage structure in relation to environmental drivers and human pressures, we analyzed resting stages of diatoms and dinoflagellates, including harmful algal bloom taxa, in the surface sediments of 3 Mediterranean regional areas. Abundance of resting stages was determined by molecular quantitative polymerase chain reaction assay. Multivariate data analysis confirmed that the abundance of resting-stage assemblages seemed related to depth. Regional differences in the composition of the resting-stage assemblages were evident and environmental drivers were correlated with those regional differences. Three main groups of samples were defined according to SST and depth thresholds. Samples from the northern and central Adriatic Sea (average SST &lt; 18°C) formed the richest assemblages, both in terms of abundance and species richness, while deep samples from all other basins (depth &gt; 368 m) were poorer and less diverse than those from shallower sites (depth ≤ 368 m). Resting-stage taxa contributed differently to the 3 groups. Diatom spores and dinoflagellate cysts were the most abundant taxa, but Alexandrium minutum cysts and Ditylum brightwellii spores also accounted for a large share of the overall inter-group compositional distance. The structure of resting-stage assemblages can be regarded as a time- and space-integrated response of a subset of phytoplankton species to environmental conditions, including the physical oceanographic dynamics that favor or prevent sedimentation of resting stages.

The influence of thermal extremes on coral reef fish behaviour in the Arabian/Persian Gulf

Despite increasing environmental variability within marine ecosystems, little is known about how coral reef fish species will cope with future climate scenarios. The Arabian/Persian Gulf is an extreme environment, providing an opportunity to study fish behaviour on reefs with seasonal temperature ranges which include both values above the mortality threshold of Indo-Pacific reef fish, and values below the optimum temperature for growth. Summer temperatures in the Gulf are comparable to those predicted for the tropical ocean by 2090–2099. Using field observations in winter, spring and summer, and laboratory experiments, we examined the foraging activity, distance from refugia and resting time of Pomacentrus trichrourus (pale-tail damselfish). Observations of fish behaviour in natural conditions showed that individuals substantially reduced distance from refugia and feeding rate and increased resting time at sub-optimal environmental temperatures in winter (average SST = 21 °C) and summer (average SST = 34 °C), while showing high movement and feeding activity in spring (average SST = 27 °C). Diet was dominated by plankton in winter and spring, while fish used both plankton and benthic trophic resources in summer. These findings were corroborated under laboratory conditions: in a replicated aquarium experiment, time away from refugia and activity were significantly higher at 28 °C (i.e. spring temperature conditions) compared to 21 °C (i.e. winter temperature conditions). Our findings suggest that P. trichrourus may have adapted to the Arabian/Persian Gulf environment by downregulating costly activity during winter and summer and upregulating activity and increasing energy stores in spring. Such adaptive behavioural plasticity may be an important factor in the persistence of populations within increasing environmentally variable coral reef ecosystems.

Ream and run and total shoulder: patient and shoulder characteristics in five hundred forty-four concurrent cases.

Total shoulder (TSA) is commonly used to treat arthritic shoulders with intact rotator cuffs; however, some patients choose a ream and run (RnR) to avoid the potential risks and limitations of a prosthetic glenoid component. Little is known about how patients selecting each of these two procedures compare and contrast. We analyzed the patient characteristics, shoulder characteristics, and twoyear clinical outcomes of 544 patients having RnR or TSA at the same institution during the same sixyear period. Patients selecting the RnR were more likely to be male (92.0% vs. 47.0%), younger (58 ± 9 vs. 67 ± 10years), married (83.2% vs. 66.8%), from outside of our state (51.7% vs. 21.7%), commercially insured (59.1% vs. 25.2%), and to have type B2 glenoids (46.0% vs. 27.8%) as well as greater glenoid retroversion (19 ± 11 vs. 15 ± 11 degrees) (p < .001). The average twoyear SST score for the RnRs was 10.0 ± 2.6 vs. 9.5 ± 2.7 for the TSAs. The percent of maximum possible improvement (%MPI) for the RnRs averaged 72 ± 39% vs. 73 ± 29% for the TSAs. Patients with work-related shoulder problems had lower twoyear SSTs and lower %MPIs. Younger patients having TSAs did less well than older patients. Female patients having RnRs did less well than those having TSAs (p < 0.001). This investigation highlights important characteristics of patients selecting the RnR and the TSA for glenohumeral arthritis. Excellent outcomes can be achieved for appropriately selected patients having either procedure.

Cementless metaphyseal reverse shoulder arthroplasty: our preliminary experience.

Reverse shoulder arthroplasty (rTSA) is a largely used procedure with a wide variety of indications. The incidence of this surgery is increased in recent years and the literature expects similar trend for the future. Metaphyseal stem rTSA seems to be a promising solution considering major objectives the preservation of humeral bone stock and ease of revision. In our study we analyzed 19 patients treated with cementless metaphyseal stem rTSA for osteoarthritis (group A) and acute fractures (group B). In group A (7 patients) the average Constant score improved from 21,57 (16-29) to 56,85 (38-72), the average SST improved from 2,29 (1-4) to 9,43 (8-12) and the mean VAS score improved from 14,29 to 4,86. In group B (12 patients) the mean Constant-Murlay score at last follow up was 42,17; the average SST was 7 and average pain score was 8,92. Overall active range-of-motion (ROM) improved significantly. Surgical considerations, clinical (analyzing Constant score and Simple Shoulder Test) and radiological short-term outcomes are encouraging, with low rate of complications. Long term follow-up studies are necessary to confirm our findings and the potential benefits related to these implants. (www.actabiomedica.it)

Model-based computer-aided method for diagnosis of cardiovascular disease using IR thermogram.

The human thermal system maintains a core body temperature of 36.7°C. Any deviation from this causes considerable discomfort. The arteries and veins play a significant role in transferring the temperature to maintain the thermal comfort of the human system. Thus the aim of this work was to bring out the potential of thermal imaging in diagnosing the cardiovascular disease in comparison with the standard techniques. The average skin surface temperature (SST (°C)) was compared with the standard bio-signaling method electrocardiograph (ECG) and the ECG-derived heart rate variability (HRV) time domain parameters. Standard biochemical assay and one minute ECG signal were obtained from known CVD men (n=10) and age-matched men (n=10) In each subject, infra-red (IR) thermogram of selected skin area of the body was obtained. From the ECG signal, RR interval was computed using Pan-Tompkins algorithm. HRV time domain variables were also calculated. When SST(°C) variables using static SST (°C) alone were utilized in the CAD model for evaluation of CVD, it was found that, Naive-Bayes classifier with variables ranking and selection by Wilcoxon method gave an accuracy of 90%, and its sensitivity and specificity were found to be 80% and 90% respectively. It was comparable to the obtained CAD model using ECG variables as a standard, whose accuracy was same, and its sensitivity and specificity were found to be 90% and 80% respectively. Also, a better accuracy of 95% (sensitivity-90%, specificity-75%) could be achieved in classifying the normal and CVD subjects when the static average SST (°C) was used along with the HRV time domain variables. Thus the inclusion of IR thermogram in the CAD model along with standard variables improves the accuracy of cardiovascular disease evaluation.

SST variability in the eastern intertropical Indian Ocean – On the search for trigger mechanisms of IOD events

This study focusses on the variability of sea surface temperature in the eastern intertropical Indian Ocean off the coasts of Sumatra and Java - a region that is central to the Indian Ocean Dipole (IOD). Using multiplatform satellite and ARGO data, here we show that the appearance of vast areas of anomalously cold surface water off the southwest Sumatran coast during positive IOD (pIOD) events is preconditioned by upwelling favourable winds along Sumatra's central west coast (1–3°S). A simple theory of coastal upwelling along coasts of finite horizontal extent, developed in this work, can explain this SST response. While this theory is consistent with the pIOD events of the years 1994, 1997 and 2006, it uncovers the existence of another strong upwelling event in the year 2011 that is missed when calculating average SST anomalies in the wider region (i.e. the Dipole Mode Index). In addition, we also derived the surface circulation establishing in the study region during pIOD events. This circulation pattern indicates that equatorward transport of colder water by a classical upwelling jet (that we call the South West Sumatra Current) reinforces negative (cold) SST anomalies off southwest Sumatra.

A preliminary study for the assessment of hypertension using static and dynamic IR thermograms

Structural changes in blood vessels occur due to prolonged hypertension. Early detection of blood pressure (mm Hg) is essential for disease prevention. The aim of this work is to propose a computer-aided diagnostic (CADx) model for the diagnosis of hypertension using variables derived from non-contact static and dynamic thermal imaging in comparison with the pulse wave velocity (PWV)-derived parameters. Static and dynamic infrared (IR) thermograms of selected skin areas of the body from known hypertensive (n=14) and age- and sex-matched normal subjects were captured. The average skin surface temperature [SST (°C)] of selected skin areas of the body was calculated from a static IR thermogram. After denoising the dynamic IR thermogram using wavelets, the statistical variables power, mean, standard deviation (SD), variance, skewness and kurtosis were calculated. The variables derived from both static and dynamic thermograms were used to develop the CADx model. The performance of the CAD model was also tested by feature selection using principal component analysis (PCA). An accuracy of 75% (sensitivity=78.6%, specificity=71.4%) could be achieved with the average SST (°C) of the static IR thermogram alone. The statistical variables derived from the dynamic IR thermogram alone gave an accuracy of 82% (and 85% after feature selection by PCA), whereas the accuracy using standard methods like variables derived from PWV was only 71.4% (with and without feature selection). The highest accuracy of 89% could be achieved by combining variables like average SST (°C) measured from static and dynamic IR thermograms and PWV-derived variables.

Latitudinal variation in the symbiotic dinoflagellate Symbiodinium of the common reef zoantharian Palythoa tuberculosa on the Saudi Arabian coast of the Red Sea

Aim The Red Sea presents an ideal setting to explore the variability of Symbiodinium over environmental, latitudinal and geographical gradients. We used sequences from two molecular markers to examine genetic diversity of Symbiodinium associated with the widely distributed zoantharian Palythoa tuberculosa in the northern and central Red Sea. Location Northern and central Red Sea. Methods Specimens (n = 329) were collected from 15 locations. Sequence data from nuclear ribosomal ITS2 (n = 269) and chloroplast minicircle psbAncr (n = 173) were phylogenetically analysed (maximum likelihood, neighbour joining), and Symbiodinium types identified for each P. tuberculosa colony. To establish whether environment was a strong predictor of Symbiodinium psbAncr lineage, SST, chlorophyll-a, salinity, and depth data were fit into a multinomial logistic regression using the package VGAM in the R statistical environment. Results Based on ITS2 and psbAncr results, P. tuberculosa colonies were shown to be in symbioses with Symbiodinium clade C (n = 172) and clade D (n = 1). Within clade C, four psbAncr lineages were observed; closely related lineages designated Pt-1-a and Pt-1-b, and closely related lineages Pt-3-a and Pt-3-b. By location, Pt-1-a dominated the sites within the Gulf of Aqaba (c. 86%, 37/43 colonies). At the entrance to the Gulf of Aqaba, Pt-3-a dominated (c. 88%, 15/17), while the more southern remaining sites in the Red Sea were dominated by Pt-3-b (c. 78%, 89/113). Main conclusions Multinomial logistic regression analyses established that predictions based on the combination of temperature, chlorophyll-a and salinity accurately reflected symbiont distributions in the central and northern Red Sea. Palythoa tuberculosa host Pt-1-a in the coldest region, the Gulf of Aqaba (annual average SST = 24.5–25.0 °C), while immediately to the south Pt-3-a dominates (SST = 26.0–26.5 °C), with warmest southern sites dominated by Pt-3-b (SST > 26.5 °C). The Gulf of Aqaba is a unique environment, and more research on Symbiodinium outside the Gulf is required to understand symbiont diversity patterns within the Red Sea.