Deep Ocean Water Research Articles

Spectral correlation in MODIS water-leaving reflectance retrieval uncertainty.

Spectral remote sensing reflectance, Rrs(λ) (sr-1), is the fundamental quantity used to derive a host of bio-optical and biogeochemical properties of the water column from satellite ocean color measurements. Estimation of uncertainty in those derived geophysical products is therefore dependent on knowledge of the uncertainty in satellite-retrieved Rrs. Furthermore, since the associated algorithms require Rrs at multiple spectral bands, the spectral (i.e., band-to-band) error covariance in Rrs is needed to accurately estimate the uncertainty in those derived properties. This study establishes a derivative-based approach for propagating instrument random noise, instrument systematic uncertainty, and forward model uncertainty into Rrs, as retrieved using NASA's multiple-scattering epsilon (MSEPS) atmospheric correction algorithm, to generate pixel-level error covariance in Rrs. The approach is applied to measurements from Moderate Resolution Imaging Spectroradiometer (MODIS) on the Aqua satellite and verified using Monte Carlo (MC) analysis. We also make use of this full spectral error covariance in Rrs to calculate uncertainty in phytoplankton pigment chlorophyll-a concentration (chla, mg/m3) and diffuse attenuation coefficient of downwelling irradiance at 490 nm (Kd(490), m-1). Accounting for the error covariance in Rrs generally reduces the estimated relative uncertainty in chla by ∼1-2% (absolute value) in waters with chla < 0.25 mg/m3 where the color index (CI) algorithm is used. The reduction is ∼5-10% in waters with chla > 0.35 mg/m3 where the blue-green ratio (OCX) algorithm is used. Such reduction can be higher than 30% in some regions. For Kd(490), the reduction by error covariance is generally ∼2%, but can be higher than 20% in some regions. The error covariance in Rrs is further verified through forward-calculating chla from MODIS-retrieved and in situ Rrs and comparing estimated uncertainty with observed differences. An 8-day global composite of propagated uncertainty shows that the goal of 35% uncertainty in chla can be achieved over deep ocean waters (chla ≤ 0.1 mg/m3). While the derivative-based approach generates reasonable error covariance in Rrs, some assumptions should be updated as our knowledge improves. These include the inter-band error correlation in top-of-atmosphere reflectance, and uncertainties in the calibration of MODIS 869 nm band, in ancillary data, and in the in situ data used for system vicarious calibration.

Numerical analysis of air–water two-phase upflow in artificial upwelling of deep ocean water by airlift pump

Artificial upwelling by the use of airlift pump is regarded as an effective way in utilizing deep ocean water and actualizing ocean fertilization. This paper focuses on numerical analysis of steady air–water two-phase flow in a vertical pipe of an airlift system based on one-dimensional multi-fluid model. The depth distributions of 6 physical quantities such as volumetric fractions and axial velocities of two phases, air density and pressure are calculated by solving the governing equations or by integrating the vector form of nonhomogeneous ordinary differential equation for two-phase flow interval. Upon successful verification of the present numerical model through a comparison with precedent theoretical and experimental results in case of a vertical pipe with length of 7.86 m, the model is extended to the case of artificial upwelling from water depth of 2000 m. The effects of submerged depth of air–water mixer on the pumped amount of water and the depth distributions of 6 physical quantities are considered.

Biodegradation of Typical Plastics: From Microbial Diversity to Metabolic Mechanisms.

Plastic production has increased dramatically, leading to accumulated plastic waste in the ocean. Marine plastics can be broken down into microplastics (<5 mm) by sunlight, machinery, and pressure. The accumulation of microplastics in organisms and the release of plastic additives can adversely affect the health of marine organisms. Biodegradation is one way to address plastic pollution in an environmentally friendly manner. Marine microorganisms can be more adapted to fluctuating environmental conditions such as salinity, temperature, pH, and pressure compared with terrestrial microorganisms, providing new opportunities to address plastic pollution. Pseudomonadota (Proteobacteria), Bacteroidota (Bacteroidetes), Bacillota (Firmicutes), and Cyanobacteria were frequently found on plastic biofilms and may degrade plastics. Currently, diverse plastic-degrading bacteria are being isolated from marine environments such as offshore and deep oceanic waters, especially Pseudomonas spp. Bacillus spp. Alcanivoras spp. and Actinomycetes. Some marine fungi and algae have also been revealed as plastic degraders. In this review, we focused on the advances in plastic biodegradation by marine microorganisms and their enzymes (esterase, cutinase, laccase, etc.) involved in the process of biodegradation of polyethylene terephthalate (PET), polystyrene (PS), polyethylene (PE), polyvinyl chloride (PVC), and polypropylene (PP) and highlighted the need to study plastic biodegradation in the deep sea.

Low-temperature FTIR spectroscopy of the L/Q switch of proteorhodopsin.

Rhodopsins are photoreceptive membrane proteins containing a retinal chromophore, and the color tuning mechanism in rhodopsins is one of the important topics. Color switch is a color-determining residue at the same position, where replacement of red- and blue-shifting amino acids in two wild-type rhodopsins causes spectral blue- and red-shifts, respectively. The first and most famous color switch in microbial rhodopsins is the L/Q switch in proteorhodopsins (PRs). Green- or blue-absorbing PR (GPR or BPR) contains Leu and Gln at position 105 of the C-helix (TM3), respectively, and their replacement converted absorbing colors. The L/Q switch enables bacteria to absorb green or blue light in shallow or deep ocean waters, respectively. Although Gln and Leu are hydrophilic and hydrophobic residues, respectively, a comprehensive mutation study of position 105 in GPR revealed that the λmax correlated with the volume of residues, not the hydropathy index. To gain structural insights into the mechanism, we applied low-temperature FTIR spectroscopy of L105Q GPR, and the obtained spectra were compared with those of GPR and BPR. The difference FTIR spectra of L105Q GPR were similar to those of BPR, not GPR, implying that the L/Q switch converts the GPR structure into a BPR structure in terms of the local environments of the retinal chromophore. It includes retinal skeletal vibration, hydrogen-bonding strength of the protonated Schiff base, amide-A vibration (peptide backbone), and protein-bound water molecules. Consequently color is switched accompanying such structural alterations, and known as the L/Q switch.

The Study on the Fundamental of Dark and Bright Solitons

Abstract: The words bright and dark are taken from the field of optics, where they are used to describe the bright spots and black shadows that appear in optical fibres. However, in the 1830s, soliton observations were made in water. Oceanographers were initially taken aback by the discovery in the 1960s and 1970s that bright solitons were present on the surface of deep ocean waters. However, numerous experiments have since been conducted to investigate and validate the phenomenon, some of which have identified bright solitons as the cause of rogue waves at sea. Both bright and dark solitons have now been observed in BoseEinstein condensates, plasmas, fibre optics, and other environments. [30]

Fluctuating oxygenation and dynamic iron cycling in the late Paleoproterozoic ocean

The mid-Proterozoic (1.8–0.8 billion years ago, Ga) is generally considered to have been an interval of relative stasis in terms of environmental and biological evolution. Indeed, in terms of ocean redox chemistry, deeper ocean waters are considered to have dominantly remained anoxic and ferruginous throughout this interval. Despite the persistence of ferruginous conditions, the mid-Proterozoic has long been considered notable for a general absence of iron formations (IFs), in stark contrast to the major intervals of IF deposition that occurred in the ferruginous oceans of the earlier Precambrian. In recent years, however, sporadic IFs have been found in the mid-Proterozoic, but controls on the genesis of these IFs, as well as implications for the evolution of ocean chemistry, remain poorly understood. Here, we present major and trace element data, iron speciation systematics, and organic carbon and iron isotope data for the ∼1.64 Ga Chuanlinggou Formation, which hosts a sudden reappearance of substantial IF deposition on the North China Craton. The Chuanlinggou IF has low Y/Ho ratios (24–26), slightly positive Eu anomalies (Eu/Eu* = 1.14–1.47), no Ce anomalies, slightly positive δ56Fe values (0.05 to 0.35 ‰), and high δ13Corg values (−29 ‰) relative to deeper water facies (down to −33.4 ‰). These observations provide support for a redox-stratified ocean with oxic surface waters overlying ferruginous deeper waters, and further suggest that IF deposition occurred in a stratified ocean with a shallow redoxcline during an interval of elevated Fe concentrations. Specifically, we suggest that the development of relatively intense ferruginous conditions was likely a consequence of hydrothermal activity during the breakup of the Columbia supercontinent. Microaerophilic iron-oxidizing bacteria and/or anoxygenic photosynthesizers likely played a key role in the generation of the Chuanlinggou IF. Importantly, however, data for shales that overly the Chuanlinggou IF suggest episodic intervals of deeper water oxygenation. Thus, similar to recent studies of the later Mesoproterozoic ocean, our data indicate that ocean chemistry during the latest Paleoproterozoic may have been more dynamic than previously considered, with fluctuating oxygen and iron levels likely exerting a limiting constraint on both the evolution of eukaryotes and the deposition of IFs across the immense interval of time encapsulated by the mid-Proterozoic.

Exploring global accessibility of deep ocean water for sea water air conditioning (SWAC) process: Identifying feasibility areas depending on temperature source

Sea Water Air Conditioning (SWAC) technology is a highly efficient alternative to conventional air conditioning system using renewable marine energy to provide cooling to buildings. However, its implementation requires access to Deep Ocean Water (DOW) at 4–5 °C, thus SWAC is only viable in coastal regions. Furthermore, one of the major obstacles to its global development is the investment cost that remains high. This cost is strongly linked to the bathymetry of the installation location as it determines the length of the drawing pipeline, which accounts for the largest share of the investment cost. Knowing the temperature and bathymetry profiles will enable the establishment of the financial viability of SWAC technology in a specific location. This paper presents an analysis identifying areas of feasibility on a worldwide scale for standard SWAC implementation first. Then, it explores an alternative design with a higher drawing point for seawater at 12 °C (coupled with a High Temperature District Cooling), which reduces the cost by shortening the drawing pipeline and allows for more locations to be suitable for this technology. Additionally, the impact of the El Niño/Southern Oscillation (ENSO) is also considered since a shallower drawing point makes it more sensitive to temperature variations.

Informing ocean color inversion products by seeding with ancillary observations.

Ocean reflectance inversion algorithms provide many products used in ecological and biogeochemical models. While a number of different inversion approaches exist, they all use only spectral remote-sensing reflectances (Rrs(λ)) as input to derive inherent optical properties (IOPs) in optically deep oceanic waters. However, information content in Rrs(λ) is limited, so spectral inversion algorithms may benefit from additional inputs. Here, we test the simplest possible case of ingesting optical data ('seeding') within an inversion scheme (the Generalized Inherent Optical Property algorithm framework default configuration (GIOP-DC)) with both simulated and satellite datasets of an independently known or estimated IOP, the particulate backscattering coefficient at 532 nm (bbp(532)). We find that the seeded-inversion absorption products are substantially different and more accurate than those generated by the standard implementation. On global scales, seasonal patterns in seeded-inversion absorption products vary by more than 50% compared to absorption from the GIOP-DC. This study proposes one framework in which to consider the next generation of ocean color inversion schemes by highlighting the possibility of adding information collected with an independent sensor.

Reliability assessment of the ocean thermal energy conversion systems through Monte Carlo simulation considering outside temperature variation

AbstractThe ocean thermal energy conversion (OTEC) systems, as renewable energy-based power plants, have the potential to play a significant role in meeting future electricity demands due to the vast expanse of the world's oceans. These systems employ the temperature difference between surface ocean waters and deep ocean waters to drive a thermodynamic cycle and produce electricity. The temperature of deep ocean waters, approximately 1000 m below the surface, is approximately 4 °C, while surface ocean temperatures typically range between 20 and 30 °C. The generated power of OTEC systems is dependent on these temperature differences and may vary with changes in surface ocean temperatures. In this study, the main focus is to find the impact of temperature variation on the failure rates of OTEC system components and the generated power output of these plants. The findings indicate that as the demand for the power system increases, its reliability decreases. In order to improve the reliability of the power system, the integration of a new generation unit, such as the close cycle OTEC power plant under investigation, could be necessary. The findings also indicate the importance of considering temperature variation in the evaluation of the reliability of such types of power plants based on renewable energy.

Design, Implementation, and Evaluation of an External Pose-Tracking System for Underwater Cameras

To advance underwater computer vision and robotics from lab environments and clear water scenarios to the deep dark ocean or murky coastal waters, representative benchmarks and realistic datasets with ground truth information are required. In particular, determining the camera pose is essential for many underwater robotic or photogrammetric applications and known ground truth is mandatory to evaluate the performance of, e.g., simultaneous localization and mapping approaches in such extreme environments. This paper presents the conception, calibration, and implementation of an external reference system for determining the underwater camera pose in real time. The approach, based on an HTC Vive tracking system in air, calculates the underwater camera pose by fusing the poses of two controllers tracked above the water surface of a tank. It is shown that the mean deviation of this approach to an optical marker-based reference in air is less than 3 mm and 0.3∘\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$^{\\circ }$$\\end{document}. Finally, the usability of the system for underwater applications is demonstrated.

Using Deep Ocean Water in the Fermentation of Antrodia cinnamomea to Boost Magnesium Ion Bioabsorption and Anti-Inflammatory Effects in the Brain of an Alzheimer’s Disease Rat Model

Alzheimer’s disease (AD) is a neurodegenerative disorder characterized by the deposition of amyloid β-peptide (Aβ) and subsequent oxidative inflammatory response, leading to brain damage and memory loss. This study explores the potential of Antrodia cinnamomea (AC), a Taiwan-native fungus known for its anti-inflammatory and antioxidant properties. The metabolites of AC, including dehydroeburicoic acid (DEA), 4-acetylantroquinonol B (4-AAQB), dehydrosulphurenic acid (DSA), and polysaccharides, were of particular interest. In the experiment, deep ocean water (DOW) was used to facilitate the solid-state fermentation of Antrodia cinnamomea NTTU 206 (D-AC), aiming to enhance its functional components. The impact of D-AC on the modulation of AD-related risk factors and the augmentation of cognitive abilities was subsequently evaluated in an AD rat model. This model was established via consecutive infusions of Aβ40 into the brain over a 28-day period. The administration of D-AC resulted in remarkable improvements in the rats’ reference memory, spatial probe test, and working memory. Notably, it restored the hippocampal magnesium levels by upregulating the expression of the magnesium transporter MAGT1. Concurrently, D-AC significantly downregulated the expressions of β-secretase 1 (BACE1) and the phosphorylated tau protein (p-tau), which were both implicated in AD progression. Additionally, it mitigated inflammatory responses, as suggested by the decreased levels of tumor necrosis factor α (TNF-α), interleukin-1β (IL-1β), and interleukin-6 (IL-6) in the hippocampus and cerebral cortex. Ultimately, the ability of D-AC to restore the brain magnesium levels, attenuate inflammatory responses, and reduce hippocampal Aβ40 deposition led to significant improvements in the cognitive decline of AD rats. D-AC demonstrated a comparable efficacy with its counterpart, AC fruiting bodies (F-AC group), despite their componential differences. This study underscores the potential of D-AC, enriched through fermentation, as a novel dietary strategy for Alzheimer’s disease prevention.

Stalagmite-based long-term and multi-centennial hydroclimatic variations in southwestern China during the Holocene and relations to global climate change

Knowing the behavior of the Asian summer monsoon (ASM) and its global correlation help understand roles of the ASM in global climate change. Here we synthesize a stalagmite δ18O record, based on a new record and an available nearby record, both covering the nearly entire Holocene. The synthesized δ18O record correlates with meridional migration of the Intertropical Convergence Zone (ITCZ), and with change in inter-subtropical insolation contrast throughout the Holocene. However, its correlation with the Atlantic meridional overturning circulation (AMOC) broken down during the period of the strongest ASM, when the AMOC weakened. This scenario points to a persistent influence of the ITCZ and subtropical insolation contrast on the change in ASM throughout the Holocene. Our record also correlates with a change in atmospheric CO2 concentration on the multi-millennial scale. These correlations of our cave record with variations in the ITCZ, subtropical insolation contrast, and CO2 level indicate that changes in low-latitude climates, including the ASM, were involved in the evolution of the Holocene CO2 concentration. These changes in the low-latitude climates were likely connected with variation in the Holocene southern westerly wind, which modulated upwelling of carbon-enriched deep ocean water around Antarctica. On the multi-centennial scale, seven weak ASM events are identified, with the magnitudes of the Younger Dryas and the events at 9.8 ka and 8.2 ka event broadly three and two times larger than the other ones. These events have a quasi-period of approximately 1.463 ka. This period in the monsoon regime probably arose from solar activity, but involving the feedback of ENSO. In summary, our study provides insights into the connection of the Holocene ASM with tropical climate, and into the involvement of the ASM in the change of the Holocene CO2 concentration.

Kynurenine promotes Calcitonin secretion and reduces cortisol in the Japanese flounder Paralichthys olivaceus

Deep ocean water (DOW) exerts positive effects on the growth of marine organisms, suggesting the presence of unknown component(s) that facilitate their aquaculture. We observed that DOW suppressed plasma cortisol (i.e., a stress marker) concentration in Japanese flounder (Paralichthys olivaceus) reared under high-density condition. RNA-sequencing analysis of flounder brains showed that when compared to surface seawater (SSW)-reared fish, DOW-reared fish had lower expression of hypothalamic (i.e., corticotropin-releasing hormone) and pituitary (i.e., proopiomelanocortin, including adrenocorticotropic hormone) hormone-encoding genes. Moreover, DOW-mediated regulation of gene expression was linked to decreased blood cortisol concentration in DOW-reared fish. Our results indicate that DOW activated osteoblasts in fish scales and facilitated the production of Calcitonin, a hypocalcemic hormone that acts as an analgesic. We then provide evidence that the Calcitonin produced is involved in the regulatory network of genes controlling cortisol secretion. In addition, the indole component kynurenine was identified as the component responsible for osteoblast activation in DOW. Furthermore, kynurenine increased plasma Calcitonin concentrations in flounders reared under high-density condition, while it decreased plasma cortisol concentration. Taken together, we propose that kynurenine in DOW exerts a cortisol-reducing effect in flounders by facilitating Calcitonin production by osteoblasts in the scales.

Cordyceps cicadae NTTU 868 Mycelia Fermented with Deep Ocean Water Minerals Prevents D-Galactose-Induced Memory Deficits by Inhibiting Oxidative Inflammatory Factors and Aging-Related Risk Factors.

Cordyceps cicadae, a medicinal fungus that is abundant in bioactive compounds such as N6-(2-hydroxyethyl)-adenosine (HEA) and polysaccharides, possesses remarkable anti-inflammatory, antioxidant, and nerve damage recovery properties. Deep ocean water (DOW) contains minerals that can be absorbed and transformed into organic forms by fungi fermentation. Recent studies have shown that culturing C. cicadae in DOW can enhance its therapeutic benefits by increasing the levels of bioactive compounds and minerals' bioavailibility. In this study, we investigated the effects of DOW-cultured C. cicadae (DCC) on brain damage and memory impairment induced by D-galactose in rats. Our results indicate that DCC and its metabolite HEA can improve memory ability and exhibit potent antioxidant activity and free radical scavenging in D-galactose-induced aging rats (p < 0.05). Additionally, DCC can mitigate the expression of inflammatory factors, such as tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), interleukin-1β (IL-1β), cyclooxygenase-2 (COX-2), and inducible nitric oxide synthase (iNOS), thereby preventing brain aging. Furthermore, DCC showed a significant decrease in the expression of the aging-related proteins glial fibrillary acidic protein (GFAP) and presenilin 1 (PS1). By reducing brain oxidation and aging-related factors, DOW-cultured C. cicadae demonstrate enhanced anti-inflammatory, antioxidant, and neuroprotective effects, making it a promising therapeutic agent for preventing and treating age-related brain damage and cognitive impairment.

Potential Pathway for Reliable Long-Term CO2 Storage as Clathrate Hydrates in Marine Environments

A countermeasure to global warming is removing high CO2 amounts from the atmosphere and locating the emitted CO2 into long-term stable carbon storage sites. The sequestration technologies must be reliable, long-lasting, and environmentally friendly. An alternative and innovative approach that may meet the sequestration requirements is CO2 storage as clathrate hydrates in marine environments. Extensive research has been devoted to CO2-CH4 replacement in natural gas hydrates. Another option is the direct formation of CO2 hydrates into deep ocean water or into marine underfloor sediments. This article deals with the positioning of direct hydrate-based CO2 storage among the other traditional geological options and the discussion of new, by-far, state-of-the-art knowledge required for the development of a hydrate-based CO2 storage pathway that is reliable, stable, durable, efficient, and environmentally benign.

Sentience, Sentences, and Sentiment: Sensing Deep-Ocean Sediment through Artistic Practice

At this moment of climate crisis, deep-ocean carbon sequestration has been proposed as a strategy to curtail greenhouse gas emissions. The video article Sentience, Sentences, &amp;amp; Sentiment: Sensing Deep-Ocean Sediment through Artistic Practice explores ecological attunement and the role of language in perceiving the more-than-human—specifically the deep-ocean ecosystems facing potential carbon sequestration, ocean acidification, global heating, and eutrophication. The article unfolds an artist’s account of process for kór (core). An interdisciplinary artwork and slow installation, kór (core) features a deep-ocean sediment core extracted between Greenland and Iceland at a depth of 1,682m during a June 2021 science research cruise. In Icelandic, kór means choir or chorus; it is pronounced similarly to the English-language core. The article features video aboard the research vessel, the acquisition of the core, conceptual documentation of the resulting artwork kór (core), participant interviews, soundscape recordings, and an aria composed through the installation.kór (core) performs a slow installation as a point of activation, where community members contribute to, think with, and create in the context of considering the sentient being-ness of sediment. On a chalkboard, community members mark their reactions to and within the presence of deep-ocean water and sediment. This article shows multilingual sense-making (English, Icelandic, Polish, Danish, Spanish) and the sensorial materialities of bodies (human, cetacean, water, etc.) in the contexts of marine-terrestrial biospheres impacted by the climate crisis. The video aims to elucidate a creative investigation into an expanded notion of relations—crucial for collaborative survivorship in our multi-entity worldings.

Summer Hydrography and Circulation in Storfjorden, Svalbard, Following a Record Low Winter Sea‐Ice Extent in the Barents Sea

AbstractStorfjorden, Svalbard, hosts a polynya in winter and is an important source region of Brine‐enriched Shelf Water (BSW) that, if dense enough, feeds the Arctic Ocean deep water reservoir. Changes in the BSW production may thus have far‐reaching impacts. We analyze the water mass distribution and circulation in Storfjorden and the trough south of it, Storfjordrenna, using hydrographic sections occupied in July 2016, following a winter characterized by the lowest ice coverage recorded in the Barents Sea. These observations reveal an unusual hydrographic state, characterized at the surface by the near absence of Melt Water and Storfjorden Surface Water, replaced by a saltier water mass. At depth, BSW (maximum salinity of 34.95) was found from the bottom up to 90 m, above the 120‐m deep sill at the mouth to Storfjordrenna. However, no gravity driven overflow was observed downstream of the sill: the dome of BSW remained locked over the depression in a cyclonic circulation pattern consistent with a stratified Taylor column. Observations further reveal a previously unreported intrusion of Atlantic Water (AW) far into the fjord, promoting isopycnal mixing with entrapped Arctic Water. This intrusion was possibly favored by positive wind stress curl anomalies over Svalbardbanken and Storfjordrenna. The bottom plume exiting Storfjordrenna was weak, carrying Polar Front Water rather than BSW, too light to sink underneath the AW layer at Fram Strait. Whether Storfjorden switched durably to a new hydrographic state, following the observed Atlantification of the Barents Sea after 2005, remains to be established.

Energy performance assessment of Sea Water Air Conditioning (SWAC) as a solution toward net zero carbon emissions: A case study in French Polynesia

Sea Water Air Conditioning (SWAC) technology uses deep ocean water to cool buildings. It is a non-intermittent renewable thermal energy used directly without any transformation. It may replace other air-conditioning systems powered by electrical energy (mechanical vapor compression thermodynamic cycle) or powered by other renewable energies (solar heating and cooling systems). Despite its theoretical appeal as a solution to help achieve net-zero carbon emissions, and the existence of successful deployments, SWAC technology remains scarce worldwide mainly due to its investment cost (CAPEX). One reason for this failure to scale might be the absence of experimental data detailing energy performance of SWAC systems in real-world, commercial settings. Here is presented the performance of an existing 2.4 MW SWAC system, operated by The Brando resort on the atoll of Tetiaroa in French Polynesia. Under a tropical climate, experimental results show that the Coefficient of Performance (COP) of the SWAC system can reach 20 to 150 depending on the secondary loop length, compared with conventional vapor compression systems that peak at around 5 for the most efficient. To put this in terms of carbon emissions avoided, conventional unitary split systems running in similar hotels on neighboring islands in French Polynesia (COP around 3.5) emit some 860 Tons/year compared to the estimated 225 Tons/year emitted (approximated with the emissions factor of French Polynesia in 2019) operating the Tetiaroa SWAC.

Why Are the Eastern Margins of Ocean Basins Full of Fish?

At the eastern side of the Atlantic and Pacific Oceans, Earth’s rotation combined with winds blowing toward the equator push water away from the coasts. Deep ocean water rises to replace what was pushed away, in a process called upwelling. The colder, deep water that rises to the surface is rich in nutrients and oxygen, and it supports healthy ecosystems. That is, upwelling in coastal oceans equals lots of fish! There are four coastlines where upwelling is crucial, known as eastern boundary upwelling systems (EBUS for short). These regions cover &amp;lt;3% of the world’s ocean area, but they are responsible for 20% of the global fish catch. EBUS change constantly along with Earth’s changing climate. Given their extraordinary biological productivity, it is very important to understand how global warming may impact EBUS. In this article, we describe what EBUS are and discuss how climate change may affect them and the fish populations in their ecosystems.

Numerical Study on Hydrodynamics of Submerged Permeable Breakwater under Impacts of Focused Wave Groups Using a Nonhydrostatic Wave Model

Extreme waves, called rogue waves or freak waves, usually occur unexpectedly and with very large wave heights. In recent years, extreme waves were reported not only in deep ocean waters but also in shallow waters, which threaten the safety and intactness of the coastal regions. To prevent the coastal infrastructures and communities from the devastating power of extreme surges and waves, many coastal defense structures were built along the coastline, i.e., submerged permeable breakwaters. However, the number of studies on the hydrodynamic characteristics of a submerged permeable breakwater under the impact of extreme waves is relatively few. In addition, wave focusing has been widely used to generate extreme waves in the past few decades. Hence, as a necessary supplement to the previous research work, the hydrodynamic performance of a submerged permeable breakwater under the impacts of focused wave groups was numerically studied by using a nonhydrostatic numerical wave model (NHWAVE). The influences of several main factors, such as the incident significant wave height, water depth, wave peak period, porosity of the breakwater (n), and the side slope angle of the breakwater, were considered. It is expected that the results of this study will further strengthen the research on the hydrodynamic characteristics of a submerged permeable breakwater under extreme wave conditions.