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This study explores the skeletal growth of Porites panamensis, a common reef-building coral species, and its response to extreme environmental conditions. Sclerochronology, which involves analyzing coral growth bands, is utilized to obtain the coral’s growth parameters, including skeletal density, extension rate, and calcification rate. The study objective was to recognize insights into coral calcification mechanisms under extreme natural acidified conditions and high seawater temperatures (SWT) in hydrothermal vent environments in the Bahía Concepción, Gulf of California, Mexico. The results showed that P. panamensis has the lowest coral growth (35–84%) and a reduced calcification rate (0.26 ± 0.13 g cm−2 year−1) compared with similar corals in other regions. The conditions under which P. panamensis grew in the La Ventila vents were characterized by a mean seawater temperature of 28.5 ± 1.5 °C and a mean pH of 6.96 ± 0.19. This study represents the first analysis of sclerochronological characteristics in P. panamensis inhabiting shallow hydrothermal vent systems, demonstrating the species’ high morphological plasticity, which allows it to cope with extreme temperatures (> 30 °C) and low pH (< 7.0) conditions. The prevalence of small corals in these systems is consistent with observations from other hydrothermal vent fields, where many coral species grow in encrusting and sub-massive forms under the influence of acidified conditions. These findings reveal that coral growth strategies will be not enough to mitigate the effects of ocean acidification on coral reefs. The adaptive response of corals to acidified environments may lead to reduced coral growth, low carbonate production, and the flattening of reef systems, thereby threatening the long-term maintenance of coral reefs, and ultimately limit their ability to provide environmental goods and services. [ABSTRACT FROM AUTHOR]

In contrast to tropical and subtropical regions, where coral abundance is declining due to elevated summer seawater temperatures, expansions of coral ranges have been reported in temperate Japanese regions due to an increase in seawater temperature. However, the vulnerability of corals in temperate Japanese regions to elevated summer seawater temperatures is not well known. In this study, we assessed the bleaching state of corals with elevated seawater temperatures during summer in a temperate Japanese coastal sea around Takashima Island, using an underwear color reference card (Coral Health Chart). This study showed that the color of temperate corals turned pale with increasing seawater temperature during summer. However, the corals did not reach a bleached state. Approaching a typhoon may contribute to maintenance of coral health at Takashima Beach by mitigating high seawater temperatures during summer and preventing the accumulation of thermal stress in corals. [ABSTRACT FROM AUTHOR]

Ocean warming caused by global climate change influences the function, diversity, and community dynamics of commensal microorganisms, including the hemolymph and the gut microbiota in mussels. However, the microbiota in hard-shelled mussel (Mytilus coruscus) larvae and the effect of temperature on the microbial community structure have yet to be studied. Herein, we investigated the core microbiota of M. coruscus larvae and the impact of acute (4 h) and gradual (4 days) exposure to a rise in seawater temperature from 21 to 25 °C. Eleven core genera were identified in M. coruscus larvae by 16S rDNA gene sequencing: Alteromonas, Brevundimonas, Delftia, Microbacterium, Neptuniibacter, Neptunomonas, Pseudoalteromonas, Rhodococcus, Stenotrophomonas, Tenacibaculum, and Thalassotalea. The microbiota of larvae in the short exposure treatment was similar to the control. However, the abundance of Delftia, Neptunomonas, Pseudoalteromonadaceae, Rhodococcus, and Stenotrophomonas decreased significantly in the longexposure larvae. In contrast, at the genus level, the abundance of Tenacibaculum increased significantly. Diversity and multivariate analyses confirmed that the microbiota patterns were linked to seawater warming over the long term. Microbiota diversity did not change significantly, regardless of whether the seawater temperature increased quickly or slowly; however, we observed a significant increase in the microbiota species abundance at higher temperatures. Among the altered bacterial genera, Delftia, Neptunomonas, and Rhodococcus function in the degradation of organic compounds; Pseudoalteromonas is closely associated with mussel attachment and metamorphosis, and Tenacibaculum is an opportunistic pathogen that can cause marine mollusk death. The results suggest that marine heat waves caused by climate change may reduce the ability of symbiotic bacteria to degrade environmental toxins, will affect mussel larvae metamorphosis, and increase the abundance of opportunistic pathogens, thereby increasing the risk of disease and death of mussel larvae. [ABSTRACT FROM AUTHOR]

Large amounts of cooling water are required for the cooling process in coal-fired or nuclear power plants. Because the primary use of water in a power plant is to condense steam and remove waste heat as part of a Rankine cycle, seawater temperature (SWT) is of critical importance for electrical output in power plant applications installed at the seaside. Moreover, the analysis of SWT is an important criterion for researching sea life and global climate, and it also serves as an important indicator of climate change. In this paper, multilayer perceptron, which is in the class of a feed-forward artificial neural network, deep learning approach based on long short-term memory and bidirectional long short-term memory neural networks and data-driven methods, such as adaptive neuro-fuzzy inference system (ANFIS) accompanied by fuzzy c-means, ANFIS with grid partition and ANFIS with subtractive clustering methods were applied to make 1-day ahead SWT predictions. Analyses were conducted using 5-year daily mean SWTs measured by the Turkish State Meteorological Service for Antalya province between 2014 and 2018. The models were evaluated using mean absolute error (MAE), root-mean-square error (RMSE), and correlation coefficient (R). According to the daily SWT prediction, the best MAE, RMSE, and R values were obtained with the ANFIS-SC model, which were 0.1877 °C, 0.2683 °C, and 0.99814, respectively. [ABSTRACT FROM AUTHOR]

Copyright of International Journal of Engineering Research & Development (IJERAD) is the property of International Journal of Engineering Research & Development and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Olympic Coast National Marine Sanctuary (OCNMS), which was established in 1994 and covers an area of 8257 km2, is located along Washington State's remote and rugged outer coast towards the northernmost extent of the California Current System (CCS). In this region, summertime equatorward winds drive seasonal upwelling of cold, nutrient rich waters onto the continental shelf. These waters help fuel a highly diverse and productive ecosystem that includes marine mammal and seabird communities as well as commercially and culturally important fisheries. The sanctuary is located within the boundaries of the legally defined Usual and Accustomed (U&A) fishing grounds of four Coastal Treaty Tribes, the Hoh Tribe, Makah Tribe, Quileute Tribe, and the Quinault Indian Nation, which hold treaty fishing rights and co-manage fisheries and other natural resources within the sanctuary through state, federal, and international partnerships and agreements. This data article describes shipboard hydrographic Conductivity-Temperature-Depth (CTD) and dissolved oxygen profile data that were collected within the sanctuary at fourteen locations during mooring deployment, recovery, and maintenance cruises between the months of May and October from 2005–2023. The 792 CTD profiles were acquired using Sea-Bird Scientific 19 SeaCAT or 19plus SeaCAT CTD profilers with associated SBE-43 (Sea-Bird Electronics) or Beckman or YSI-type (Yellow Springs Instruments) dissolved oxygen sensors. The data were processed using Sea-Bird Scientific's SBE Data Processing application. These data are needed for improving our understanding of subsurface oceanographic conditions — including marine heat waves, changes in timing of spring transition to upwelling, seasonal hypoxia, and ocean acidification — in this important but undersampled region, and can be used to help improve the management of marine resources regionally and within the sanctuary. The CTD cast data are available via Zenodo at https://doi.org/10.5281/zenodo.10466124.

We propose a seawater salinity sensor array based on a micro/nanofiber Bragg grating structures, which allows for the simultaneous measurement of temperature and salinity. The proposed sensing structure is fabricated through a process involving optical fiber tapering, femtosecond laser inscription, and chemical etching. The equivalent refractive index (RI) of this sensor structure is influenced by the surrounding RI, resulting in a Bragg characteristic wavelength shift that can be used for salinity sensing. The experimental results show that the salinity sensitivity for two cascaded sensor arrays is 8.39 pm/‰ and 7.71 pm/‰, while the temperature sensitivity is 8.28 pm/°C and 8.03 pm/°C, respectively. This sensor structure is compact, exhibits excellent linearity, and offers good repeatability. It holds great potential for applications in seawater environmental monitoring and quantitative studies of seawater dispersion characteristics. [ABSTRACT FROM AUTHOR]

The Sr/Ca ratio of modern coral skeletons can record local seawater temperature (T) and is an important tool for reconstructing past environments. However, site‐specific calibrations are required to ensure accurate temperature reconstructions. Here, we examine three modern coral skeletons collected at contrasting sites on the island of Oahu, Hawaii to establish the first accurate calibrations for this region and investigate site specific influences on the calibration process. Satellite T data, which is used for many calibrations, may not be able to derive an accurate thermometer. For our shallow lagoonal sites, satellite T had smaller seasonal T ranges, which resulted in significantly higher slopes of Sr/Ca‐T compared to using in situ T. The traditional age model based on aligning only min/max values can lead to errors in the Sr/Ca‐T calibration due to variable growth rates. An enhanced age model which adds midpoint alignments between the min/max peak values can account for seasonal changes in growth rate and reduce the error. On the same island, site‐ and time period specific conditions can cause notable differences in the Sr/Ca‐T calibrations. The coral from an estuarine embayment showed a high Sr/Ca offset, likely due to high Sr/Ca in ambient seawater. For corals which experienced thermal stress, lower slopes were observed probably due to elevated Sr/Ca values during the period of thermal stress. Plain Language Summary: In this study, we established the first applicable calibration of coral skeletal Sr/Ca and seawater temperature that can be applied to corals at contrasting locations (shallow lagoon vs. deeper forereef, estuary vs. non‐estuary, and windward vs. leeward) in Hawaii. Using satellite seawater temperature for Sr/Ca‐T calibrations may not be appropriate for shallow lagoons due to significant differences in actual temperature across time. Variable seasonal extension rates can also cause errors in Sr/Ca‐T calibrations. Enhancing the age model by adding date alignment points between peak values can reduce this type of error. Terrigenous influence and thermal stress also affect the relationship between Sr/Ca and seawater temperature resulting in site and time period specific calibration relationships. Key Points: Hawaiian coral Sr/Ca‐in situ Temperature calibrations were performed at shallow lagoons, deeper forereef, and estuary embaymentsSatellite temperature (T) for shallow lagoons leads to a steeper coral Sr/Ca‐T slopes, potentially resulting in an underestimated T reconstructionCoral chronology due to seasonally variable extension rates can be improved by aligning additional midpoints between the min/max values [ABSTRACT FROM AUTHOR]

Abstract The Sr/Ca ratio of modern coral skeletons can record local seawater temperature (T) and is an important tool for reconstructing past environments. However, site‐specific calibrations are required to ensure accurate temperature reconstructions. Here, we examine three modern coral skeletons collected at contrasting sites on the island of Oahu, Hawaii to establish the first accurate calibrations for this region and investigate site specific influences on the calibration process. Satellite T data, which is used for many calibrations, may not be able to derive an accurate thermometer. For our shallow lagoonal sites, satellite T had smaller seasonal T ranges, which resulted in significantly higher slopes of Sr/Ca‐T compared to using in situ T. The traditional age model based on aligning only min/max values can lead to errors in the Sr/Ca‐T calibration due to variable growth rates. An enhanced age model which adds midpoint alignments between the min/max peak values can account for seasonal changes in growth rate and reduce the error. On the same island, site‐ and time period specific conditions can cause notable differences in the Sr/Ca‐T calibrations. The coral from an estuarine embayment showed a high Sr/Ca offset, likely due to high Sr/Ca in ambient seawater. For corals which experienced thermal stress, lower slopes were observed probably due to elevated Sr/Ca values during the period of thermal stress.

Reanalysis datasets have been widely used in oceanography and climate change studies. We evaluate the applicability of eight reanalysis datasets in the Yellow and Bohai seas (YBS), including ERA5, SODA3.4.2, GREPv2, C-GLORSv7, GLORYS2v4, ORAS5, CORAv1.0, and CORAv2.0, compared to the observation data from the oceanic stations and an observation-based dataset of global instantaneous 3D thermohaline fields (ARMOR3D). The results show that the sea surface temperature (SST) of ERA5, ORAS5, and GREPv2 agrees with the observations, while the temperature profiles of C-GLORSv7 and GREPv2 are in good agreement with the ARMOR3D observation. In terms of ocean salinity, the salinity profile of the CORA series is in better agreement than other reanalysis datasets. Overall, GREPv2 is more consistent with seawater temperature observations in the YBS than others, while the CORA series reproduces the salinity variation better. GREPv2, a multi-model ensemble product, delivers a better depiction of seawater temperature and salinity than that of the individual member dataset. Most reanalysis datasets can reproduce the interannual variation of SST in the YBS well with improved performance in the last decade. The spatial distribution differences occur mostly in offshore waters with a warmer but less salinity bias. [ABSTRACT FROM AUTHOR]

Severe typhoon "In-Fa" passed through the northwestern region of East China Sea (ECS) in July 2021, affecting oceanic variables such as seawater temperature, salinity, and chlorophyll-a (Chl-a) concentration over the upwelling area. In this study, we analyzed the influence of the passage of typhoon "In-Fa" on the marine environment over the Upwelling Area off the Yangtze River Estuary (UAYRE) and the Upwelling Area of Zhoushan (UAZS). The results showed a significant decrease in sea surface temperature (SST) during the "In-Fa" typhoon, with maximum SST reductions of 2.98 °C in the UAYRE and 1.46 °C in the UAZS, which showed a "right bias" (indicating a greater cooling effect on the right side of the typhoon path compared to the left side). "In-Fa" influenced the temperature and salinity structure of the study areas and deepened the mixed layer depth (MLD). The MLD varied from the shallowest values of 2.02 m (18 July) to the deepest values of 19.4 m (26 July) in the UAYRE and from 2.43 m (18 July) to 16.79 m (25 July) in the UAZS. Furthermore, "In-Fa" led to an increase in sea surface Chl-a concentration, with a maximum Chl-a concentration enhancement of 285.58% (from 20 July to 28 July) in the UAYRE and 233.33% (from 20 July to 27 July) in the UAZS. The Ekman suction effect of "In-Fa" strengthened the upwelling, facilitating the transport of deep-sea nutrients to the upper ocean and providing favorable conditions for the growth of phytoplankton, thus benefiting the reproduction and survival of zooplankton, fish, and shrimp. This study contributes to understanding the mechanisms by which typhoons impact the ocean environment in upwelling area and provides valuable insights for the sustainable development of marine fisheries resources. [ABSTRACT FROM AUTHOR]

Extreme weather phenomena have become more frequent and intense in recent decades in the context of climate change, and these include heat waves that affect both the atmosphere and seawater masses. In 2022, a summer marine heatwave (MHW) affected the entire Mediterranean Sea, and temperatures up to 5 °C above seasonal mean were reached in the Ligurian Sea in the NW part of the Mediterranean basin. In this scenario, the waters of the Port of Genoa (at the northern apex of the Ligurian Sea) distinguished themselves by maintaining lower temperatures than those of the open sea (a maximum gradient of −6.1 °C on 9 August 2022) after the passage of a fast-moving storm. In this study, the weather and sea parameters of the period (June–December 2022) are analysed to determine the phenomenon that caused the drop in temperatures in the water masses of the Port of Genoa. The sudden cooling of the water masses inside the port was caused by a heavy rainfall event in early August. Moreover, the isolation of the port water masses due to the weak dynamics of the period kept them stationary and locked inside the port. Seawater temperatures inside the port slowly rose again after the event, remaining cooler than outside temperatures throughout August (−0.3 °C on 31 August), reaching and exceeding outside temperatures on 3 September (26.4 °C), and remaining warmer until 3 November 2022 (21.5 °C). [ABSTRACT FROM AUTHOR]

During 2010–2018 in Denmark, 638 patients had Vibrio infections diagnosed and 521 patients had Shewanella infections diagnosed. Most cases occurred in years with high seawater temperatures. The substantial increase in those infections, with some causing septicemia, calls for clinical awareness and mandatory notification policies.

Lipids may serve as energy reserves to support coral calcification, allow acclimation to higher temperatures, and are implicated in the control of CaCO3 precipitation. Here, we report the lipid composition of the soft tissues (including host and symbionts) of 7 massive Porites spp. coral colonies (4 × P. lutea and 3 × P. murrayensis), which were cultured under different pCO2 concentrations (180, 260, 400 and 750 µatm) and at two temperatures (25 ℃ and 28 ℃), below the thermal stress threshold. We report the fatty acid methyl esters (FAME), free fatty acid (FFA) to total fatty acid content, sterol and wax ester profiles, and identify two ketones (n-alkanone) and three long chain aldehyde (n-alkanal) derivatives. Increasing seawater temperature significantly increases the contributions of FFAs to the total lipids, of C18:2 and C20:0 to the total FFA pool, of C14:0 to total FAME, and of campesterol to total sterol. The temperature increase also reduces the contributions of unusual fatty acid derivatives to total lipids, of C14:0, C15:0, C16:0 and C17:0 saturated free fatty acids to total FFAs, and of C16:0 FA to total FAME. Fatty acids are implicated in the control of membrane structure fluidity and the observed changes may promote acclimation and thermostability as temperature varies. Seawater pCO2 has no significant effect on the composition of tissue lipids with the exception that the contribution of C14:0 FA to total lipid content is significantly lower at 180 µatm compared to 260 and 750 µatm. Decreased contribution of total sterols and unusual fatty acid derivatives and increased contribution of total FFAs to total lipids are observed in the fastest calcifying coral (a P. lutea specimen) compared to the other corals, under all pCO2 and temperature conditions. Although a rapid calcifier this genotype has been shown previously to exhibit pronounced abnormal changes in skeletal morphology in response to decreased seawater pCO2. Variations in tissue lipid composition between coral genotypes may influence their resilience to future climate change. [ABSTRACT FROM AUTHOR]

The highly biologically productive northern California Current, which includes the Oregon continental shelf, is an archetypal eastern boundary region with summertime upwelling driven by prevailing equatorward winds and wintertime downwelling driven by prevailing poleward winds. Between 1960 and 1990, monitoring programs and process studies conducted off the central Oregon coast advanced the understanding of many oceanographic processes, including coastal trapped waves, seasonal upwelling and downwelling in eastern boundary upwelling systems, and seasonal variability of coastal currents. Starting in 1997, the U.S. Global Ocean Ecosystems Dynamics – Long Term Observational Program (GLOBEC-LTOP) continued those monitoring and process study efforts by conducting routine CTD (Conductivity, Temperature, and Depth) and biological sampling survey cruises along the Newport Hydrographic Line (NHL; 44.652°N, 124.1 – 124.65°W), located west of Newport, Oregon. Additionally, GLOBEC-LTOP maintained a mooring slightly south of the NHL, nominally at 44.64°N, 124.30°W, on the 81-meter isobath. This location is referred to as NH-10, as it is located 10 nautical miles or 18.5 km west of Newport. A mooring was first deployed at NH-10 in August 1997. This subsurface mooring collected water column velocity data using an upward-looking acoustic Doppler current profiler. A second mooring with a surface expression was deployed at NH-10 starting in April 1999. This mooring included velocity, temperature and conductivity measurements throughout the water column as well as meteorological measurements. GLOBEC-LTOP and the Oregon State University (OSU) National Oceanographic Partnership Program (NOPP) provided funding for the NH-10 moorings from August 1997 to December 2004. Since June 2006, the NH-10 site has been occupied by a series of moorings operated and maintained by OSU with funding from the Oregon Coastal Ocean Observing System (OrCOOS), the Northwest Association of Networked Ocean Observing Systems (NANOOS), the Center for Coastal Margin Observation & Prediction (CMOP), and most recently the Ocean Observatories Initiative (OOI). While the objectives of these programs differed, each program contributed to long-term observing efforts with moorings routinely measuring meteorological and physical oceanographic variables. This article provides a brief description of each of the six programs, their associated moorings at NH-10, and our efforts to combine over twenty years of temperature, practical salinity, and velocity data into one coherent, hourly averaged, quality-controlled data set. Additionally, the data set includes best-fit seasonal cycles calculated at a daily temporal resolution for each variable using harmonic analysis with a three-harmonic fit to the observations. The stitched together, hourly NH-10 time series and seasonal cycles are available via Zenodo at https://doi.org/10.5281/zenodo.7582475.

In this study, we conducted two surveys in the central and southern parts of the South China Sea, in autumn 2012 and spring 2013. Six juvenile tuna species were caught in each survey. Gradient forest analysis (GFA) and a generalized additive model (GAM) were used to analyze the relationship between the catch per unit effort (CPUE) for the juvenile tuna species and six sea temperature indices for the South China Sea. In the GFA, the temperature difference between the sea surface and 50 m depth (D50) showed the highest importance to CPUE than other indices, which indicates that D50 was the best predictor of the abundance of juvenile tuna species. The GAM analysis showed that lower deep-water temperature, a shallow mixed layer depth, and a higher difference in temperature between the surface and deeper water were associated with increased CPUE. The results indicate that a relatively rapid decrease in vertical water temperature is favorable for the aggregation of juvenile tuna. These results contribute to understanding of the distribution mechanism of juvenile tuna species in the South China Sea and provide a scientific basis for the rational development and utilization of tuna resources. [ABSTRACT FROM AUTHOR]

The macrophyte Gelidium corneum (Hudson) J. V. Lamouroux, 1813 plays an important role as an ecosystem engineer on temperate rocky shores on the northeastern Atlantic coast. However, its cover and population biomass have declined in recent decades within the southern Bay of Biscay. This study aimed to identify the environmental thresholds, with respect to seawater temperature and irradiance, that influence the development capacity of newly formed individuals of G. corneum through vegetative reproduction. Therefore, an in situ experiment was conducted at two depths within the range of distribution of this species (5 and 12 m) and at two coastal sites on the north coast of Spain (east and west coasts of the Cantabria region, Spain). Our results revealed that G. corneum apical fragments undergoing vegetative propagation developed many new shoots over a period of sixteen weeks. The temperature and irradiance seemed to contribute to the length reached by the new fronds, whereas the number of recruits remained constant throughout the duration of the experiment. Given the slow growth rate characteristic of this species, the total shoot length in this study reached 2.97 cm, which confirms the gradual and restrained developmental pattern during the early stages of its life. We also quantified bite marks at the tips of the new plants, and more than three-quarters of them presented these signs by the final month of the study. Our study provides valuable insights into the growth process of the endangered species G. corneum through vegetative propagation and elucidates the impact that abiotic and biotic factors can have on its growth. [Display omitted] • Gelidium corneum has a strong ability to develop new shoots through vegetative propagation. • New shoots grow slower than adult individuals. • Elevated mean summer seawater temperatures (above 22 °C) seem to slow down frond elongation. [ABSTRACT FROM AUTHOR]

We estimated the error range of the simulated salinity and seawater temperature based on the uncertainty of the river discharge into Ise Bay in a nowcasting numerical simulation model. We used two methods for calculating the river discharge forcing. In the first method, precipitation was used as the input for the storage function method. In the second method, the Basin Rainfall Index was used, which is a nowcasting dataset of river discharge simulated by the Japan Meteorological Agency. The uncertainty in annual river discharge in both methods was estimated to be within ±30 %. Simulations were conducted using the hydrodynamic simulation model. Annual simulation error ranges associated with the uncertainty in river discharge for salinity and seawater temperature were estimated to be approximately ±1.2 and ±0.15 °C, respectively. We proposed a practical research procedure that can be applied to other models and the simulation of the water environment of coastal and estuary areas. • Procedure for determining uncertainty in river discharge is proposed. • Salinity and water temperature error ranges with river uncertainty were estimated. • River discharge uncertainty affects spatiotemporal salinity/water temperature bias. • Practical research procedure is proposed that can be applied to other model tasks. • Error range of hypoxia in seawater can be estimated applying the proposed method. [ABSTRACT FROM AUTHOR]

We propose a seawater salinity sensor array based on a micro/nanofiber Bragg grating structures, which allows for the simultaneous measurement of temperature and salinity. The proposed sensing structure is fabricated through a process involving optical fiber tapering, femtosecond laser inscription, and chemical etching. The equivalent refractive index (RI) of this sensor structure is influenced by the surrounding RI, resulting in a Bragg characteristic wavelength shift that can be used for salinity sensing. The experimental results show that the salinity sensitivity for two cascaded sensor arrays is 8.39 pm/‰ and 7.71 pm/‰, while the temperature sensitivity is 8.28 pm/°C and 8.03 pm/°C, respectively. This sensor structure is compact, exhibits excellent linearity, and offers good repeatability. It holds great potential for applications in seawater environmental monitoring and quantitative studies of seawater dispersion characteristics.

Copyright of Journal of Refrigeration is the property of Journal of Refrigeration Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

A case study of the manufacture of an OTEC factory on a floating ship has been carried out using 100 MW Titanium material at a fairly expensive cost, so the OTEC system was researched using a copper-tin alloy. The behavior of the tin-copper heat exchanger between the Aspen Plus simulation and the Computational Fluid Dynamics (CFD) simulation on Shell And Tube evaporators of Bonnet Divided Flow fixed and Bonnet One-pass Shell fixed (BEM) types is investigated. The difference in temperature between water at sea level of 29 °C and water at a depth of 1000 meters at a temperature of 5 °C is assumed to produce electricity. A marine thermal energy conversion power plant is a continuous source of energy sourced from nature an evaporator heat exchanger with ammonia working fluid will produce power that can drive a turbine forwarded to a generator. The simulation results of CFD of a Bonnet Divided Flow fixed type Heat Exchanger on the hot water inlet line has a temperature of 29.9 °C, when exiting the evaporator shell the temperature decreases to 26.4 °C. At the inlet line, the working fluid of ammonia enters the evaporator at 7.9 °C and when it leaves the tube, the temperature rises to 26.3 °C. The best results of the simulation of Aspen Plus Heat Exchanger type BEM Inlet Ammonia temperature 8 °C and at CFD 7.99 °C. Meanwhile, at the ammonia outlet at 28 °C and in the CFD simulation, the ammonia outlet temperature was 28.21 °C. Aspen Plus Inlet heating water temperature is 30 °C, and in CFD simulation, the temperature is 29.99 °C. While the heating water outlet is 28 °C, and in the CFD simulation, the heating water outlet is 28.15 °C. The conclusion from the simulation results is that the BEM-type heat exchanger is very good and suitable for experimental prototyping. [ABSTRACT FROM AUTHOR]

Extreme weather phenomena have become more frequent and intense in recent decades in the context of climate change, and these include heat waves that affect both the atmosphere and seawater masses. In 2022, a summer marine heatwave (MHW) affected the entire Mediterranean Sea, and temperatures up to 5 °C above seasonal mean were reached in the Ligurian Sea in the NW part of the Mediterranean basin. In this scenario, the waters of the Port of Genoa (at the northern apex of the Ligurian Sea) distinguished themselves by maintaining lower temperatures than those of the open sea (a maximum gradient of −6.1 °C on 9 August 2022) after the passage of a fast-moving storm. In this study, the weather and sea parameters of the period (June–December 2022) are analysed to determine the phenomenon that caused the drop in temperatures in the water masses of the Port of Genoa. The sudden cooling of the water masses inside the port was caused by a heavy rainfall event in early August. Moreover, the isolation of the port water masses due to the weak dynamics of the period kept them stationary and locked inside the port. Seawater temperatures inside the port slowly rose again after the event, remaining cooler than outside temperatures throughout August (−0.3 °C on 31 August), reaching and exceeding outside temperatures on 3 September (26.4 °C), and remaining warmer until 3 November 2022 (21.5 °C).

Severe typhoon “In-Fa” passed through the northwestern region of East China Sea (ECS) in July 2021, affecting oceanic variables such as seawater temperature, salinity, and chlorophyll-a (Chl-a) concentration over the upwelling area. In this study, we analyzed the influence of the passage of typhoon “In-Fa” on the marine environment over the Upwelling Area off the Yangtze River Estuary (UAYRE) and the Upwelling Area of Zhoushan (UAZS). The results showed a significant decrease in sea surface temperature (SST) during the “In-Fa” typhoon, with maximum SST reductions of 2.98 °C in the UAYRE and 1.46 °C in the UAZS, which showed a “right bias” (indicating a greater cooling effect on the right side of the typhoon path compared to the left side). “In-Fa” influenced the temperature and salinity structure of the study areas and deepened the mixed layer depth (MLD). The MLD varied from the shallowest values of 2.02 m (18 July) to the deepest values of 19.4 m (26 July) in the UAYRE and from 2.43 m (18 July) to 16.79 m (25 July) in the UAZS. Furthermore, “In-Fa” led to an increase in sea surface Chl-a concentration, with a maximum Chl-a concentration enhancement of 285.58% (from 20 July to 28 July) in the UAYRE and 233.33% (from 20 July to 27 July) in the UAZS. The Ekman suction effect of “In-Fa” strengthened the upwelling, facilitating the transport of deep-sea nutrients to the upper ocean and providing favorable conditions for the growth of phytoplankton, thus benefiting the reproduction and survival of zooplankton, fish, and shrimp. This study contributes to understanding the mechanisms by which typhoons impact the ocean environment in upwelling area and provides valuable insights for the sustainable development of marine fisheries resources.

Eggs of Sepioteuthis sp. 1 were collected off Tanegashima Island and incubated at 19, 23, and 26 °C. Those eggs hatched after 42, 19, and 17 days, respectively. Development took less time at higher temperatures, and at 23 °C proceeded faster than reported for S. sp. 2 cultured at 25 °C. Paralarval S. sp. 1 were cultured at 23 °C, with one surviving female and male mated at approximately 175 days after hatching. About 204 days post-hatching, the female deposited eggs on artificial seagrass and cannibalized the male. Eggs were deposited five times from 29 to 80 days after mating, after which the female died. The number of eggs in egg sheaths (0–4) was lower than counts reported for egg masses in nature (mean 9 eggs). The terminal mantle length of the mature S. sp. 1 male was 169 mm, and of the female, 173 mm. In nature, individuals at mantle lengths below 250 mm are immature, suggesting that S. sp. 1 is downsized and precocious in captivity. [ABSTRACT FROM AUTHOR]

Many species across a wide range of taxa and habitats display phenological shifts and differences in response to both environmental gradients and climate change. Moreover, the wide‐scale decline of numerous ecosystems is leading to increasing efforts to identify zones that might serve as natural refuges from various disturbances, including ocean warming. One such refuge was suggested to be that of the deep coral reefs, but whether depth can provide coral populations with a viable and reproductive refuge remains unclear. Given the global coral‐reef degradation and the key role that corals play as ecosystem engineers, their reproductive ecology has been widely studied. A particular knowledge gap nonetheless exists regarding coral reproductive phenology along a depth gradient. Filling in this gap may uncover the environmental cues that regulate coral reproduction, leading to better predictions of population connectivity, and their possible responses to climate change and other environmental changes. Here, using long‐term in situ observations of the soft coral Rhytisma fulvum's reproductive activity along its entire depth range (0–45 m), we examined the relationship among several environmental factors and the coral's reproductive phenology and activity over five successive annual breeding seasons. Compared with the shallow depths, a lower number of reproducing colonies was found in habitats deeper than 30 m, highlighting possible constraints on coral reproduction at the deeper end of their range. Our results further revealed that an increase in seawater temperature over 1–2‐day intervals during the breeding season correlated with the onset of reproductive activity along the depth gradient, leading to different reproductive periodicities in different depths. These differences suggest that differential temperature regimes and reproductive timing across depth may create intraspecific temporal reproductive segregation, possibly reducing connectivity among populations along a depth gradient. Moreover, we found high variability among years in both the timing of breeding activities and in the level of reproductive synchrony among corals from different depths. Overall, our study questions whether depth can provide a long‐term and viable refuge for corals in the face of global environmental changes. [ABSTRACT FROM AUTHOR]

Simple Summary: Red sea bream iridoviral disease (RSIVD) generates serious economic losses by causing mass mortality events of rock bream during the season with high water temperature in the Republic of Korea and other Asian countries. However, very few studies have investigated RSIV kinetics in rock bream under various rearing water temperatures. In this paper, we investigated the viral load shedding of RSIV into seawater after artificially infecting rock bream (Oplegnathus fasciatus) with the virus. Overall, our data suggest that the viral load shedding of RSIV into seawater varies depending on water temperature and virus inoculation concentration. Our results reveal the potential of non-invasive virus detection approaches, such as the utilization of environmental DNA in fish farms. In addition, we showed that the quantitative analysis of seawater viruses can indirectly improve our understanding of disease progression in fish, potentially contributing to enhanced disease control. Red sea bream iridoviral disease (RSIVD) causes serious economic losses in the aquaculture industry. In this paper, we evaluated RSIV kinetics in rock bream under various rearing water temperatures and different RSIV inoculation concentrations. High viral copy numbers (approximately 103.7–106.7 RSIV genome copies/L/g) were observed during the period of active fish mortality after RSIV infection at all concentrations in the tanks (25 °C and 20 °C). In the group injected with 104 RSIV genome copies/fish, RSIV was not detected at 21–30 days post-infection (dpi) in the rearing seawater. In rock bream infected at 15 °C and subjected to increasing water temperature (1 °C/d until 25 °C) 3 days later, the virus replication rate and number of viral copies shed into the rearing seawater increased. With the decrease in temperature (1 °C/d) from 25 to 15 °C after the infection, the virus replicated rapidly and was released at high loads on the initial 3–5 dpi, whereas the number of viral copies in the fish and seawater decreased after 14 dpi. These results indicate that the number of viral copies shed into the rearing seawater varies depending on the RSIV infection level in rock bream. [ABSTRACT FROM AUTHOR]

The Oregon continental shelf is embedded within the northern California Current System, a wind-driven, eastern boundary system that includes the equatorward flowing California Current and the poleward flowing California Undercurrent. During spring and summer months, equatorward winds drive the upwelling of cold, nutrient-rich, and oxygen-poor waters from depth onto the shelf, fueling a highly productive marine ecosystem that supports several valuable commercial fisheries. This data article describes a time series of hydrographic data collected on a biweekly to monthly schedule from March 1997 to July 2021 along the Newport Hydrographic Line (NHL; 44.652°N, 124.1 – 124.65°W) located west of Newport, Oregon. The NHL, with its 2–4 week sampling rate and inclusion of biological data such as zooplankton net tows, is the only long-term, high-frequency dataset of its kind for the California Current and as such is crucial to understanding the connectivity between changes in ocean-climate and ecosystem structure and function. Data were collected using Sea-Bird Scientific conductivity, temperature, depth (CTD) profilers with associated dissolved oxygen sensors at seven stations located between 1.9 and 46.3 km from shore. Water depths for the seven stations range from 30 to 296 m. Data collected during each cruise were processed using Sea-Bird Scientific's Seasoft software package. These CTD station data were gridded to a 0.01° x 1 dbar longitude - pressure grid using linear interpolation to create cross-shelf hydrographic sections of temperature, practical salinity, potential density, spiciness, and dissolved oxygen. From the gridded section data, seasonal climatologies were calculated for each variable at each location in the longitude - pressure section using harmonic analysis with a three-harmonic fit to the gridded transect observations. The station data, gridded transect data and monthly climatologies for all five variables are available via Zenodo at https://doi.org/10.5281/zenodo.5814071.

In this letter, we propose a compact hybrid fiber-optic sensor for seawater temperature and salinity simultaneous measurements. The device consists of a hollow-core fiber (HCF)-based Fabry-Perot interferometer (FPI) and no-core fiber (NCF)-based anti-resonance (AR) structure. A U-shaped groove is inscribed in the HCF for salinity sensing, and a section of the polymer coating is retained on the NCF for temperature measurement. The incident light is partially reflected at the HCF fusion end-faces and forms the FPI spectrum, while the transmission light in the NCF cladding is coupled to the polymer coating and forms the AR phenomenon. In theoretical modeling, the temperature and salinity responses of the hybrid sensor are analyzed separately, and the corresponding sensitivities are calculated theoretically. In the experiment, the results show that the temperature and salinity sensitivities are -4.948 nm/°C and 0.235 nm/‰, respectively. In addition, the calibration test, time stability, and repeatability of the sensor are also evaluated by the experiments. The construction method of this hybrid sensing structure is flexible and accurate, so it is expected to be applied in the seawater parameter measurements. [ABSTRACT FROM AUTHOR]

Climatic signals preserved in the skeletal growth bands of massive corals offer a long-term perspective that allows understanding sea surface temperature changes at different time scales. In the Caribbean Sea and the Gulf of Mexico, coral species such as Orbicella faveolata present massive growth forms in shallow waters that facilitate dating of their skeleton, allowing to perform paleoenvironmental studies in coastal areas where instrumental records are scarce and cover short time periods. This study aimed to characterize coral geochemical records in the skeleton of a hermatypic coral O. faveolata collected in the Cayo Santa María (Cuba) reef and to reconstruct seawater surface annual temperatures for the last two centuries. Records of 230 years for Li/Ca, Sr/Ca, Mg/Ca, U/Ca, Li/Mg, and Sr-U were obtained. The Li/Ca indicator allowed the reconstruction of SST in the study area from 1778 to 2015, indicating an overall increase of 0.77 °C in the last 50 years. In addition, Li/Ca corroborated with high accuracy the characteristic warming and cooling periods reported for the Caribbean Sea and the Gulf of Mexico since 1778. Orbicella faveolata proved to contain a good multidecadal record of annual temperature and of the Atlantic Multidecadal Variability. These results are the first long-term reconstruction of SST in the Cuban coastal zone and provide relevant information to understand global warming in the Caribbean. [ABSTRACT FROM AUTHOR]

This study evaluates the swimming behaviour of pre-settled fish larvae of the triplefin Helcogrammoides chil­ensis (Tripterygiidae) in relation to local environmental conditions. Larval aggregations were recorded on rocky reefs off central Chile during the austral summer of 2014 and 2016 to describe their swimming behaviour (i.e. solitary, shoaling, schooling) and relate it to in situ water temperature, wind stress, wind speed and turbulence. Shoaling and solitary behaviour were influenced only by wind-induced turbulence in 2014 and by seawater temperature and wind stress in 2016. Schooling behaviour was not influenced by any of the environmental variables. In situ swimming behaviour of fish larvae has been little investigated, and this work proposes a non-invasive in situ methodology for studying fish larval behaviour.

Reliable records of Southern Ocean seawater palaeotemperatures are important because this region plays a significant role in regulating global climate change. Biomarkers such as GDGT-based indices have been effectively used to reconstruct seawater temperatures. We analysed the composition and distribution of iGDGTs, OH-GDGTs and brGDGTs and calculated GDGT-based temperature indices in surface sediments from Prydz Bay, East Antarctica. Our results showed that iGDGTs, OH-GDGTs and brGDGTs are all produced in situ, with iGDGTs and OH-GDGTs mostly synthesized by Thaumarchaeota. Concentrations of iGDGTs, OH-GDGTs and brGDGTs showed similar spatial distributions and decreased from the continental shelf towards the deep ocean. The highest concentrations were in the inner bay, which is attributed to a combination of (1) bathymetry that reduces water exchange, (2) the Prydz Bay Gyre stabilizing the upper water column and (3) sea ice that releases archaea and bacteria. Among the temperature indices based on iGDGTs, OH-GDGTs and combinations therein, those based on OH-GDGTs showed the strongest correlation with seawater temperature. Some OH-GDGT-based indices (e.g., OH-0/OHs, OH-1/OHs, OH-2/OHs and RI-OH′) exhibited a stronger correlation with annual subsurface ocean temperature (100–200 m), which may be related to archaeal habitats and production mechanisms. Our study suggests that RI-OH′ and OH-0/OHs could be used as indicators of annual subsurface ocean temperature in Antarctic marginal seas.

In this study, we conducted two surveys in the central and southern parts of the South China Sea, in autumn 2012 and spring 2013. Six juvenile tuna species were caught in each survey. Gradient forest analysis (GFA) and a generalized additive model (GAM) were used to analyze the relationship between the catch per unit effort (CPUE) for the juvenile tuna species and six sea temperature indices for the South China Sea. In the GFA, the temperature difference between the sea surface and 50 m depth (D50) showed the highest importance to CPUE than other indices, which indicates that D50 was the best predictor of the abundance of juvenile tuna species. The GAM analysis showed that lower deep-water temperature, a shallow mixed layer depth, and a higher difference in temperature between the surface and deeper water were associated with increased CPUE. The results indicate that a relatively rapid decrease in vertical water temperature is favorable for the aggregation of juvenile tuna. These results contribute to understanding of the distribution mechanism of juvenile tuna species in the South China Sea and provide a scientific basis for the rational development and utilization of tuna resources.

Reef-building corals are found across > 30° of latitude from tropical to temperate regions, where they occupy habitats greatly differing in seawater temperature and light regimes. It remains largely unknown, however, how the demography of corals differs across this gradient of environmental conditions. Variation in coral growth is especially important to coral populations, because aspects of coral demography are dependent on colony size, with both fecundity and survivorship increasing with larger colonies. Here we tested for latitudinal variation in annual growth rate and survival of juvenile corals, using 11 study locations extending from 17° S to 33° N in the West and South Pacific. Regression analyses revealed a significant decline in annual growth rates with increasing latitude, whereas no significant latitudinal pattern was detected in annual survival. Seawater temperature showed a significant and positive association with annual growth rates. Growth rates varied among the four common genera, allowing them to be ranked Acropora > Pocillopora > Porites > Dipsastraea. Acropora and Pocillopora showed more variation in growth rates across latitudes than Porites and Dipsastraea. Although the present data have limitations with regard to difference in depths, survey periods, and replication among locations, they provide evidence that a higher capacity for growth of individual colonies may facilitate population growth, and hence population recovery following disturbances, at lower latitudes. These trends are likely to be best developed in Acropora and Pocillopora, which have high rates of colony growth. [ABSTRACT FROM AUTHOR]

This study is concerned with the seasonal development of a fouling community on artificial surfaces in marine coastal waters at a depth of 1.5–2 m. In the fall–winter period (October–February), Cryptosula pallasiana (Moll); colonial ascidia Botrillus schlosseri (Pallas); and attached ciliates of the genera Zoothamnium, Vorticella, Ephelota, Dendrosoma, and Folliculina form a layer of spotty fouling. Multispecies fouling communities develop during the summer–fall season (July–November). C. pallasiana, Conopeum seurati (Canu), and Amphibalanus improvises (Darwin), which settle simultaneously, form the first tier of fouling. The filamentous bryozoans Bowerbankia gracilis (Leidy) and polychaetes of the Serpulidae and Spionidae families settle in July–August and form a second fouling tier. Tunicates Molgula euprocta (Drasche), the hydroid Obelia loveni (Allman), and mollusks Мytilus galloprovincialis (Lamarck) and Mytilaster lineatus (Gmelin) larvae (which settle in September) continue the fouling succession during the fall period. The results reflect the biodiversity of the southwestern coastal waters of the Crimea and the impact on the fouling succession of the climatic factor, specifically, the temperature of seawater, which is rising as a result of global warming. [ABSTRACT FROM AUTHOR]

Red sea bream iridoviral disease (RSIVD) causes serious economic losses in the aquaculture industry. In this paper, we evaluated RSIV kinetics in rock bream under various rearing water temperatures and different RSIV inoculation concentrations. High viral copy numbers (approximately 103.7–106.7 RSIV genome copies/L/g) were observed during the period of active fish mortality after RSIV infection at all concentrations in the tanks (25 °C and 20 °C). In the group injected with 104 RSIV genome copies/fish, RSIV was not detected at 21–30 days post-infection (dpi) in the rearing seawater. In rock bream infected at 15 °C and subjected to increasing water temperature (1 °C/d until 25 °C) 3 days later, the virus replication rate and number of viral copies shed into the rearing seawater increased. With the decrease in temperature (1 °C/d) from 25 to 15 °C after the infection, the virus replicated rapidly and was released at high loads on the initial 3–5 dpi, whereas the number of viral copies in the fish and seawater decreased after 14 dpi. These results indicate that the number of viral copies shed into the rearing seawater varies depending on the RSIV infection level in rock bream.

Temporal trends in the size composition (length frequency) and length–weight (L–W) relationship of chokka squid Loligo reynaudii on the south coast of South Africa were assessed over periods spanning 22 years: length frequencies from 1996 to 2017 (with 15 years represented); and L–W relationships over 9 years between 1994 and 2016. To allow for comparison, identical data selection and processing was adopted for all years considered (i.e. identical period of 60 days in spring–summer; the same depths and areas; chokka with empty stomachs; and squid of the same maturity stage). Although there were no significant long-term temporal trends in the mean lengths, there was a significant short-term drop in the mean lengths over the years 2014–2017 (especially in females), which could not be attributed with certainty to any cause. A tentative explanation is that this drop might be linked to the introduction of an additional closed season in these years. The estimated parameters of the L–W relationship also revealed no trend over the years considered. Investigation of the caecum colour, which indicates the state of starvation (white: 8 h on average after food ingestion; yellow: 6 to 7 h after food ingestion), showed significantly more starving males than starving females. Starvation of males on the spawning grounds might be associated with the spawning behaviour of chokka. [ABSTRACT FROM AUTHOR]

Global increases in temperature are altering land-sea temperature gradients. Bakun (1990) hypothesized that changes within these gradients will directly affect atmospheric pressure cells associated with the development of winds and will consequently impact upwelling patterns within ecologically important Eastern Boundary Upwelling Systems (EBUS). In this study we used daily time series of NOAA Optimally Interpolated sea surface temperature (SST) and ERA 5 reanalysis wind products to calculate a series novel of metrics related to upwelling dynamics. We then use these to objectively describe upwelling signals in terms of their frequency, intensity and duration throughout the four EBUS during summer months over the last 37 years (1982–2019). We found that a decrease (increase) in SST is associated with an increase (decrease) in the number of upwelling “events,” a decrease (increase) in the intensity of upwelling, and an increase (decrease) in the cumulative intensity of upwelling, with differences between EBUS and regions within EBUS. The Humboldt Current is the only EBUS that shows a consistent response from north to south with a general intensification of upwelling. However, we could not provide clear evidence for associated changes in the wind dynamics hypothesized to drive the upwelling dynamics.

During the past decades, the aquaculture industry has developed rapidly, due to drop in wild fish catch. Water quality variables play major role in aquaculture operations, specifically seawater temperature has major impact on the metabolism of the fish species and therefore on the growth rate too. Since the fish farming business relies on the growth rate of the species to plan and operate the farm, seawater temperature becomes crucial information. With the availability of hydrodynamic modeling tools and global ocean information source such as Copernicus Marine Environment Monitoring Service (CMEMS), seawater temperature can be simulated for practically any coast with dynamic downscaling approach. However, the simulated data needs to be assessed for uncertainties for enabling informed decision making using such model predictions. In this paper, a coastal 3D hydrodynamic model aiming at simulating seawater temperature is developed for the southern Aegean Sea, Greece using the Delft3D Flexible Mesh modeling tool. Seawater temperature is impacted by atmospheric forces; therefore, uncertainties are assessed for seawater temperature using ensemble atmospheric forcing functions of the European Centre for Medium-Range Weather Forecasts (ECMWF) ERA5. Spatial analysis of the uncertainty indicates regions of different seawater temperature behavior within the model domain. Seasonal behavior of the vertical temperature gradient suggests that farms need to adapt different operational strategies in different seasons to make best use of the seawater temperature. The application of CMEMS data along with ECMWF ERA5 ensemble atmospheric forcing members proves to be beneficial in analyzing the uncertainties both in spatial and vertical gradient of seawater temperature.

Abstract Pacific bluefin tuna (Thunnus orientalis) is one of the commercially important species in Korea as well as other countries of the North Pacific. Korean offshore large purse seine fisheries targeting small pelagic fishes such as chub mackerel have caught T. orientalis temporarily in the east of Jeju Island. The catch of T. orientalis in March through June occupied approximately 60% of the total. The monthly catch around Jeju Island from 2004 to 2013 showed a negative correlation (r = − 0.755, p

Recruitment is related to the occupation of the substrate by fouling organisms. It plays an important role in the maintenance and distribution of benthic populations, being under the influence of biotic and abiotic factors. In the present work, the recruitment of calcareous sponges was monitored over two years in a marina at Todos os Santos Bay, a large bay in the tropical portion of the Brazilian coast. Artificial plates were immersed, being replaced bimonthly and the potential influence of the seawater temperature, photoperiod and precipitation on the number of sponge recruits was tested. The results showed that the number of calcareous sponge recruits had significant temporal variation. Nevertheless, different species showed different patterns over time. Significant differences were observed for Sycon avus, Sycon sp. and Leucandra serrata, and the periods with the highest number of recruits were different amongst them. Sycon bellum, Paraleucilla incomposita, Leucilla sp. and Heteropia glomerosa did not show significant variation in the number of recruits over time. None of the three tested environmental factors were correlated with the number of recruits, but results indicated S. avus recruitment might be driven by seawater temperature. Our results contribute to improve the current knowledge on the dynamics of each species found on the plates and reinforce the general view that the pattern of recruitment varies greatly in Calcarea, even amongst sympatric species. [ABSTRACT FROM AUTHOR]

The increased occurrence of extreme climate events, such as marine heatwaves (MHWs), has resulted in substantial ecological impacts worldwide. To date, metrics of thermal stress within marine systems have focussed on coral communities, and less is known about measuring stress relevant to other primary producers, such as seagrasses. An extreme MHW occurred across the Western Australian coastline in the austral summer of 2010–2011, exposing marine communities to summer seawater temperatures 2–5°C warmer than average. Using a combination of satellite imagery and in situ assessments, we provide detailed maps of seagrass coverage across the entire Shark Bay World Heritage Area (ca. 13,000 km2) before (2002 and 2010) and after the MHW (2014 and 2016). Our temporal analysis of these maps documents the single largest loss in dense seagrass extent globally (1,310 km2) following an acute disturbance. Total change in seagrass extent was spatially heterogeneous, with the most extensive declines occurring in the Western Gulf, Wooramel Bank and Faure Sill. Spatial variation in seagrass loss was best explained by a model that included an interaction between two heat stress metrics, the most substantial loss occurring when degree heating weeks (DHWm) was ≥10 and the number of days exposed to extreme sea surface temperature during the MHW (DaysOver) was ≥94. Ground truthing at 622 points indicated that change in seagrass cover was predominantly due to loss of Amphibolis antarctica rather than Posidonia australis, the other prominent seagrass at Shark Bay. As seawater temperatures continue to rise and the incidence of MHWs increase globally, this work will provide a basis for identifying areas of meadow degradation, or stability and recovery, and potential areas of resilience. [ABSTRACT FROM AUTHOR]

Ras Al-Zour coastal area, located in southern part of Kuwait, is the region of concentrated industrial water use and sea intake-outfall of existing power plants. There are some of undergoing construction projects such as Al-Zour Refinery, Al-Zour LNG import facility projects, and the expansion planning of existing power plant. The site of Al-Zour LNG import facility project is located close to the power plant in north direction approximately 0.6 km away from the shore between the Sulphur pier and the small boat harbor north of the breakwater. Being located only 3 km away from the massive thermal and brine discharge from power plants, the future water use of LNG regasification facility will be under the direct influence of thermal discharge from power plants and the further development of seawater resources within this area such as Al-Zour North power plant project. There are two issues regarding the seawater temperature in this area to be considered: (1) variations in background water temperature mostly under combined effect of local meteorology and global climate change; (2) increase of temperature due to the expansion of the thermal discharge of expanded power plant. Annual water temperatures of two candidate locations of the seawater intake for Al-Zour LNG regasification facility were measured during 2017, which shows a typical seasonal variation of a local seawater temperature with an added effect of the neighboring thermal outfall. The numerical model study was performed by using MIKE3-DHI to reproduce 2017-measurement of the sea water temperature during June–July based on the meteorological hindcast data from ECMWF (European Centre for Medium-Range Weather Forecasts) and the thermal discharge input from the southern power plants. It was found that the daily sea water temperature at the measurement location is mainly affected by thermal plume dispersion oscillating with the phase of tidal current. Thermal discharge expansion plan in ~10 km area around the new facility should be considered to obtain the exactly estimated intake water temperature limit during the design life of the facility. [ABSTRACT FROM AUTHOR]

Sargassum ilicifolium, the dominant brown macroalgae in the northeast coastal area of Taiwan, is a crucial member in the marine ecosystem. Recently, various bioactive compounds and extracts within the Sargassum genus have been applied to disease treatment, health maintenance, the food industry, and agriculture. Therefore, the demand for this alga is increasing. To satisfy industry demand and to prevent the loss of natural stock due to harvesting without limits, the development of artificial cultivation is necessary. Following investigation of growth maturation in 2016, the present study aims to determine the optimal conditions for sexual reproduction. Our data showed that egg release and fertilization percentage were positively correlated with temperature, but sperm release was not. The optimal temperature for egg bearing and fertilization was 25 °C, which yielded 73.03 ± 10.94 eggs per receptacle over a period of 9 days and attained an 84.74 ± 6.59% fertilization percentage. Moreover, irradiance was the only stimulating factor on sperm bearing. The number of sperm released in a receptacle area (6.72 × 104 μm2) could be improved above 20% under an irradiance of 100 μmol photons m−2 s−1 compared with an irradiance of 20 or 50 μmol photons m−2 s−1. Thus, this study could provide the preliminary cultivation condition for developing the artificial technique of S. ilicifolium. [ABSTRACT FROM AUTHOR]

The effects of seawater temperature on the physiological performance of three Halimeda species were studied for a period of 28 d. Five treatments were established for Halimeda cylindracea, Halimeda opuntia and Halimeda lacunalis, in triplicate aquaria representing a factorial temperature with 24°C, 28°C, 32°C, 34°C and 36°C, respectively. The average Fv/Fm of these species ranged from 0.732 to 0.756 between 24°C and 32°C but declined sharply between 34°C (0.457±0.035) and 36°C (0.122±0.014). Calcification was highest at 28°C, with net calcification rates (Gnet) of (20.082±2.482) mg/(g•d), (12.825±1.623) mg/(g•d) and (6.411±1.029) mg/(g•d) for H. cylindracea, H. opuntia and H. lacunalis, respectively. Between 24°C and 32°C, the specific growth rate (SGR) of H. lacunalis (0.079%–0.110% d–1) was lower than that of H. cylindracea (0.652%–1.644% d–1) and H. opuntia (0.360%–1.527% d–1). Three Halimeda species gradually bleached at 36°C during the study period. Malondialdehyde (MDA) and proline levels in tissues of the three Halimeda were higher in 34–36°C than those in 24–32°C. The results indicate that seawater temperature with range of 24–32°C could benefit the growth and calcification of these Halimeda species, however, extreme temperatures above 34°C have negative impacts. The measured physiological parameters also revealed that H. cylindracea and H. opuntia displayed broader temperature tolerance than H. lacunalis. [ABSTRACT FROM AUTHOR]

Ras Al-Zour coastal area, located in southern part of Kuwait, is the region of concentrated industrial water use and sea intake-outfall of existing power plants. There are some of undergoing construction projects such as Al-Zour Refinery, Al-Zour LNG import facility projects, and the expansion planning of existing power plant. The site of Al-Zour LNG import facility project is located close to the power plant in north direction approximately 0.6 km away from the shore between the Sulphur pier and the small boat harbor north of the breakwater. Being located only 3 km away from the massive thermal and brine discharge from power plants, the future water use of LNG regasification facility will be under the direct influence of thermal discharge from power plants and the further development of seawater resources within this area such as Al-Zour North power plant project. There are two issues regarding the seawater temperature in this area to be considered: (1) variations in background water temperature mostly under combined effect of local meteorology and global climate change; (2) increase of temperature due to the expansion of the thermal discharge of expanded power plant. Annual water temperatures of two candidate locations of the seawater intake for Al-Zour LNG regasification facility were measured during 2017, which shows a typical seasonal variation of a local seawater temperature with an added effect of the neighboring thermal outfall. The numerical model study was performed by using MIKE3-DHI to reproduce 2017-measurement of the sea water temperature during June–July based on the meteorological hindcast data from ECMWF (European Centre for Medium-Range Weather Forecasts) and the thermal discharge input from the southern power plants. It was found that the daily sea water temperature at the measurement location is mainly affected by thermal plume dispersion oscillating with the phase of tidal current. Thermal discharge expansion plan in ~10 km area around the new facility should be considered to obtain the exactly estimated intake water temperature limit during the design life of the facility. [ABSTRACT FROM AUTHOR]

Reliable records of Southern Ocean seawater palaeotemperatures are important because this region plays a significant role in regulating global climate change. Biomarkers such as GDGT-based indices have been effectively used to reconstruct seawater temperatures. We analysed the composition and distribution of iGDGTs, OH-GDGTs and brGDGTs and calculated GDGT-based temperature indices in surface sediments from Prydz Bay, East Antarctica. Our results showed that iGDGTs, OH-GDGTs and brGDGTs are all produced in situ, with iGDGTs and OH-GDGTs mostly synthesized by Thaumarchaeota. Concentrations of iGDGTs, OH-GDGTs and brGDGTs showed similar spatial distributions and decreased from the continental shelf towards the deep ocean. The highest concentrations were in the inner bay, which is attributed to a combination of (1) bathymetry that reduces water exchange, (2) the Prydz Bay Gyre stabilizing the upper water column and (3) sea ice that releases archaea and bacteria. Among the temperature indices based on iGDGTs, OH-GDGTs and combinations therein, those based on OH-GDGTs showed the strongest correlation with seawater temperature. Some OH-GDGT-based indices (e.g., OH-0/ OHs, OH-1/OHs, OH-2/OHs and RI-OH′) exhibited a stronger correlation with annual subsurface ocean temperature (100–200 m), which may be related to archaeal habitats and production mechanisms. Our study suggests that RI-OH′ and OH-0/OHs could be used as indicators of annual subsurface ocean temperature in Antarctic marginal seas [ABSTRACT FROM AUTHOR]