Natural Sea Research Articles

Starkey, Lindsay. Encountering Water in Early Modern Europe and Beyond: Redefining the Universe through Natural Philosophy, Religious Reformations, and Sea Voyaging.

Starkey, Lindsay. Encountering Water in Early Modern Europe and Beyond: Redefining the Universe through Natural Philosophy, Religious Reformations, and Sea Voyaging.

Community-Based Cobia, Rachycentron canadum (Linnaeus, 1766) Culture in Open Sea Cages at Olaikuda, Pamban Island, India: An Economic Analysis of Technology Transfer Initiative

The Olaikuda Village of Pamban Island was chosen to demonstrate and transfer the open sea cage culture technology of cobia by the National Institute of Ocean Technology (NIOT). Olaikuda is a fishing hamlet with 1,000 traditional fishers who are primarily involved in trap fishing. An attempt was made to supplement their income under the societal development initiative of the NIOT. With the active participation of the local fishers of Olaikuda, 3,000 hatcheryproduced cobia, Rachycentron canadum (Linnaeus, 1766) fingerlings were stocked equally in two cages with a stocking density of 4.7 fingerlings.m-3 . The cobia stocked in sea cages were reared with the locally available low-value fishes for 8 months. The sea farmed cobia attained an average weight of 3.3 kg resulting in an average daily growth rate of 13.5 g with a survival rate of 75 %. The fish were harvested on the 245th day of culture, which yielded 7,000 kg of marketable size cobia fish (1st cage 3,687 kg and 2nd cage 3,313 kg with an FCR of 1:5.5). The harvested fish were sold at the farm gate price of USD4.42 kg-1 , fetched USD30911.84. The economic analysis revealed a profit margin of USD1.26 kg-1 . The parameters such as cost of production, productivity, profitability, socio-economic impacts of native fishers were analysed during the study. The result of this farmer-driven attempt is encouraging the farmers across the coastal states to do cage culture farming in a big way. Similar efforts in more organised massive programs will create new jobs and reduce the fishing pressure on the natural sea stocks and considered a viable alternative livelihood for the fishers’ community affected by the declining natural fishery resources and international border issues.

Екологічний туризм в умовах пандемії СОVID-19: проблеми та перспективи розвитку

The COVID-19 pandemic has transformed perceptions of life, the restoration of people to the environment, their own health and the future owner of children and humanity in general. At an unrecognized time, people around the world have faced a new production - a viral disease. Propose a reduction in the number of infectious people who want to capture the whole world: travel around the world is scheduled, the activities of these institutions are suspended, people are locked in their homes. Prosthetic total lockdown, harm to human health, through sitting in a negative impact on the psyche, physical activity The way out of this situation – domestic travel in rural areas, low-lying natural places, land and sea coasts. Therefore, this article analyzes the opportunities and threats to the development of eco-tourism during pandemics.

The Integration of Nature-Based Solutions into Climate Adaptation Policy and Planning in Bangladesh

Bangladesh is regarded as one of the most climate-vulnerable regions in South Asia due to its unique geographical location and socio-economic conditions. Natural disasters, changing temperatures, precipitation, and sea level rise have affected agricultural production, infrastructure, and livelihoods in the country. To face these challenges, nature-based solutions (NbS) can address climate change adaptation, protection and management of natural ecosystems, and biodiversity conservation. For example, in Bangladesh, coastal mangroves can protect communities from storm surge and sea level rise, forests in hilly regions can prevent landslides, and green spaces in urban areas can reduce heat stress and promote the well-being of inhabitants. However, effective design, implementation, and upscaling of NbS requires support from national policies and plans. This study reviews relevant Bangladeshi national policies from the past three decades to investigate NbS as a potential framework to address climate change and societal challenges in the country. We systematically analyzed twenty policy documents across three sectors: national development; disaster management and climate change; and environment and forest. Our study found growing emphasis on preservation, protection, and management of natural ecosystems in the national policies. However, our analysis showed that among the twenty policies, nineteen of them have no direct mention of NbS terminology. Instead, the policies include various strategies and terminologies that fall under the NbS umbrella, such as ecosystem-based adaptation, ecosystem services, and green and eco-building. However, these policies are still widely missing specific implementation guidelines, robust financial support, and institutional mechanisms for monitoring and evaluating NbS initiatives in Bangladesh. We recommend several policy actions to facilitate effective and inclusive NbS interventions in Bangladesh: enhance inter-ministry cooperation; develop national funding support; develop a national promotional campaign; pursue evidence-based research and capacity-building activities; and involve youth, marginalized people, and women. These actions can optimize the benefits of NbS to enhance the country’s resilience against climate change and foster sustainable development.

Influence of Curing Conditions on Strength Characteristics of Sea Sand Mortar

This present paper aims to investigate strength characteristics of cement mortar using natural sea sand as fine aggregate in different curing conditions. Research was carried out with making mortar mixtures by two types of cement, Portland Composite Cement (PCC) and Pozzolana Portland Cement (PPC) with tap water as mixing water. Characteristics of fine aggregate and strength of cement mortar use river sand (RS), sea sand (SS), and washed sea sand (WS) were observed. Further, specimens of cube mortar in size of 50 mm x 50 mm x 50 mm of six mortar mixture series were casted according to Indonesian Standard. At 24 hours after cube specimens were casted, cube mortar specimens were cured in three curing conditions such as tap water curing (TC), seawater curing (SC) and air curing (AC). After curing at certain period (3-day, 7-day, 14-day, and 28-day), cube mortar samples were tested in compressive strength. Results concluded that sea sand aggregate improve characteristic of mortar in compressive strength up to 28 days in all curing conditions, and there was no significant effect of type of curing water (TC and SC) on 28-day strength performance of mortar was obtained. In addition, sea sand could potentially be utilized as an aggregate in production of mortar and/or concrete.

Experimental Investigation on Floating Solar-Driven Membrane Distillation Desalination Modules.

Membrane distillation (MD) processes need a relatively mild temperature gradient as the driving force for desalination. In the field, it is reasonable to utilize solar energy as the heat source for the feed, and seawater as the infinite cold source for condensation. Solar-driven MD provides a route for the practical application of seawater desalination at a small scale. In this work, we focus on floating MD modules with a solar heating bag as the power source, and perform proof-of-principle experiments on the MD performance under various conditioning parameters, including feed flow rate, feed temperature, salinity, air gap, and sea waves. The results indicate that floating solar-driven MD modules are feasible in terms of permeate flux and salt rejection ratio, and the upward evaporation MD configuration leads to a better performance in terms of permeate flux. The simulation and experiments also show that the natural sea waves disturb the heating bag and the MD module floating on the surface of seawater, and effectively enhance the feed circulation and transport in the system.

Photocatalytic anti-biofouling coatings with dynamic surfaces of hybrid metal-organic framework nanofibrous mats for uranium (VI) separation from seawater

• Anchoring ZIF-8 by polyphenol-metal coordination, covalent and noncovalent bonds. • Self-renewing ZIF-8/TA coatings with zinc-ions-releasing and ROS-producing abilities. • Synergetic uranium adsorption by pyrogallol, amidoxime, and imidazole groups. For the commercial development of nuclear technology, the isolation of uranyl ions from sea water becomes a strategic key work. However, a major challenge remains in uranium extraction to resist marine biofouling, through suppressing microorganisms' growth and adhesion on the surface of the adsorbent. In this study, by introducing a hydrolyzable tannic acid (TA) cross-linked coating with dynamic surface, we synthesized a self-polishing hybrid zeolitic imidazolate framework-8 (ZIF-8)/amidoximed polyacrylonitrile (AOP) nanofibrous mat (AOP@ZIF-8/TA) that has durable and outstanding anti-fouling performance. Subsequently, a variety of batch adsorption tests have been undertaken to determine the efficiency of the adsorbent. As a result, the maximum uranium-adsorbing capability of 1387.37 mg/g could be acquired at pH 5.0, and the sorption of uranium was not influenced by other co-existing ions. AOP@ZIF-8/TA mat also showed a long service life with favourable sorption capability after at least 5 adsorption-desorption cycles. Most importantly, the prepared hydrolyzable ZIF-8/TA coatings with zinc-ions-releasing and ROS-producing abilities form a dynamic self-renewing surface and contribute to high resistance to biofouling. After a 25‐day uptake measurement in natural sea water, the uranium sorption equilibrium was reached with the maximal adsorption capability of 11.17 mg·g −1 . Therefore, the self-peeling surface coating has the promise to be used in the production of U(VI)-binding antibiofouling adsorbents in the raw seawater.

A dimensional metrology-based approach for corrosion measurement of ship grade steels exposed to various marine environmental conditions

ABSTRACT Corrosion-induced degradation in marine steel structures is highly dependent on the surrounding environmental conditions and sea water compositions that varies significantly around global sea water bodies. This research investigates the corrosion behaviour of ship-grade steels exposed under different sea water compositions and environmental conditions typical of the Arabian Sea. More, environmental conditions spanning those anticipated for the shipping structures operating in the highly saline and warmest regions in the Arabian Sea have been simulated in laboratory-based experiments by using heated and aerated artificial sea water. Following their exposures, the corrosion performance of coupons has been investigated using the standard weight loss and a new dimensional metrology-based approach. Besides, the corrosion products formed on the steel surfaces have been characterised using various analytical techniques. Considerably higher corrosion losses and maximum corrosion depths were observed in the nutrient-rich polluted sea waters than those recorded in the natural sea waters, as well as in the simulated artificial sea water conditions.

Revealing geomorphic changes after the occurrence of a seismic event on the south coast of Puerto Rico (2020)

A coastal geomorphological study was conducted to assess the impact of seismic events on the southern coast of Puerto Rico (PR). The goal of this study was to provide new information related to the state of the coast and its geomorphic changes associated with the seismic sequence of 28 December 2019 and the 6.4-magnitude earthquake of 7 January 2020. Coastal geomorphic changes and damage to infrastructure were documented using a combination of a geographic information system (GIS), remote sensing techniques (e.g. unmanned aircraft system [UAS] images), ground-penetrating radar (GPR), high-resolution aerial photos, and field inspection techniques. A geospatial analysis was performed to evaluate the effect of the earthquake events and understand its associated effect on coastal communities’ exposure to this hazard. The findings indicate that the 6.4-magnitude earthquake caused remarkable geomorphic changes, generating a new shape for the southern coast of PR. Coastal changes were characterized by localized coastal subsidence, coastal landslides (e.g. rockslides and rockfalls), the collapse of natural arch-forming sea stacks, changes in cliff profiles, lateral spreading, the destruction of coastal infrastructure, inland shoreline migration, and coastal flooding. This information will be useful for designing new management tools and recontextualizing existing coastal planning instruments in post-earthquake scenarios. These findings clarify the importance of seismic events and their influence on coasts within active tectonic settings.

Archaeology, Physics and Chemistry: Thoughts About a Technique Applied by Mediterranean Sponge Divers Throughout the Ages

One of the most difficult professions in history, sponge diving/fishing was widely practiced in the Mediterranean World in 19th and 20th century by Turkish, Greek, Italian and North African divers. Natural sea sponges are the main materials of the profession which extends from here to the North America in mid-20th century. Our earliest data indicate that the sponge, which is well known by many ancient texts used in ancient times, especially in cleaning, medicine, carpentry, mining, chemical industry, and military equipment, was provided by mankind to 4500 BC. The ancient texts are rich in terms of information about the usage of sponges as well as information about sponge-divers. There is a consistent similarity between the centers of the Modern Age and the centers in these ancient texts which convey information about how and where the profession is practiced. The main reason for this situation should be related to the distribution map of the valuable sponge species that human beings can use in their daily life in the Mediterranean World. The information conveyed by the modern age sponge-divers and their families show that these people wandered the Mediterranean along the sponge resources. It shows that these sponge-divers are not only interested in sponges but also supply valuable textile products especially from the Eastern Mediterranean ports and market them in their countries. In this respect, the contribution of the sponge-divers -who can be defined not only as a professional group but also as a merchant- to the acculturation process of the Mediterranean has not been realized except for a few studies. The absolute, compulsory, and continuous supply of sponges needed by the common toilets and bathrooms that serve millions of people, especially in the Greek-Roman Periods, is the most important proof that sponge diving/fishing was an important profession. When we examine the sponge fishing history from the ancient times to the Ottoman Period and almost today for some amateur sponge divers, there is an invariant technique for the sponge divers. When the sponge divers reached to the bottom of the sea, they spout the olive oil from their mouth. According to Oppian and Evliya Çelebi, the sponge divers use this method for the similar purpose, however the explanations of Oppian and Çelebi are too different from each other’s. In this study, by considering physical and chemical laws, we analysis these two different examination for the oil-expuition. We determined that the people who lived in ancient ages realized the refraction of waves, and Snell’s law before the mathematical equations found.

The Roland von Glasow Air-Sea-Ice Chamber (RvG-ASIC): an experimental facility for studying ocean–sea-ice–atmosphere interactions

Abstract. Sea ice is difficult, expensive, and potentially dangerous to observe in nature. The remoteness of the Arctic Ocean and Southern Ocean complicates sampling logistics, while the heterogeneous nature of sea ice and rapidly changing environmental conditions present challenges for conducting process studies. Here, we describe the Roland von Glasow Air-Sea-Ice Chamber (RvG-ASIC), a laboratory facility designed to reproduce polar processes and overcome some of these challenges. The RvG-ASIC is an open-topped 3.5 m3 glass tank housed in a cold room (temperature range: −55 to +30 ∘C). The RvG-ASIC is equipped with a wide suite of instruments for ocean, sea ice, and atmospheric measurements, as well as visible and UV lighting. The infrastructure, available instruments, and typical experimental protocols are described. To characterise some of the technical capabilities of our facility, we have quantified the timescale over which our chamber exchanges gas with the outside, τl=(0.66±0.07) d, and the mixing rate of our experimental ocean, τm=(4.2±0.1) min. Characterising our light field, we show that the light intensity across the tank varies by less than 10 % near the centre of the tank but drops to as low as 60 % of the maximum intensity in one corner. The temperature sensitivity of our light sources over the 400 to 700 nm range (PAR) is (0.028±0.003) W m−2 ∘C−1, with a maximum irradiance of 26.4 W m−2 at 0 ∘C; over the 320 to 380 nm range, it is (0.16±0.1) W m−2 ∘C−1, with a maximum irradiance of 5.6 W m−2 at 0 ∘C. We also present results characterising our experimental sea ice. The extinction coefficient for PAR varies from 3.7 to 6.1 m−1 when calculated from irradiance measurements exterior to the sea ice and from 4.4 to 6.2 m−1 when calculated from irradiance measurements within the sea ice. The bulk salinity of our experimental sea ice is measured using three techniques, modelled using a halo-dynamic one-dimensional (1D) gravity drainage model, and calculated from a salt and mass budget. The growth rate of our sea ice is between 2 and 4 cm d−1 for air temperatures of (-9.2±0.9) ∘C and (-26.6±0.9) ∘C. The PAR extinction coefficients, vertically integrated bulk salinities, and growth rates all lie within the range of previously reported comparable values for first-year sea ice. The vertically integrated bulk salinity and growth rates can be reproduced well by a 1D model. Taken together, the similarities between our laboratory sea ice and observations in nature, as well as our ability to reproduce our results with a model, give us confidence that sea ice grown in the RvG-ASIC is a good representation of natural sea ice.

Impact of malolactic fermentation with Lactobacillus plantarum on volatile compounds of sea buckthorn juice

Malolactic fermentation using sea buckthorn (Hippophaë rhamnoides) juice as raw material was performed with six different strains of Lactobacillus plantarum. Increasing juice pH from 2.7 to 3.5 or adapting cells to low pH (i.e., acclimation) prior to inoculation allowed malolactic fermentation with all tested strains. Moreover, reducing pH of the growth medium from 6 to 4.5 with l-malate had little or no impact on biomass production. Volatile profile of sea buckthorn juice was analyzed with HS-SPME–GC–MS before and after fermentation. A total of 92 volatiles were tentatively identified and semi-quantified from sea buckthorn juice, majority of which were esters with fruity odor descriptors. Esters and terpenes were decreased in both inoculated and control juices during incubation. Microbial activity increased the levels of acetic acid (vinegar like), free fatty acids (cheese like), ketones (buttery like), and alcohols with fruity descriptors. Conversely, aldehydes associated with “green” aroma were decreased as a result of fermentation. Juices fermented with DSM 1055 had the highest acid and alcohol content, while fermentation with DSM 13273 resulted in the highest content of ketones. Compared to inoculation with other strains, fermentation with strains DSM 16365 and DSM 100813 resulted in rapid malolactic fermentation, less production of volatile acids, and lower loss of esters and terpenes important for natural sea buckthorn flavor.

Abiotic stability promotes dinoflagellate blooms in marine coastal ecosystems

Despite a large array of knowledge about triggers and drivers of phytoplankton dynamics in the sea coastal waters there is still no comprehensive understanding of what combinations of hydro-physical, hydro-chemical and biotic characteristics induce harmful algal blooms (HABs), which nowadays expand globally under the conditions of warm weather, high irradiance, and reduced turbulent water mixing in the absence of wind. Recent laboratory experiments highlighted the importance of abiotic (physico-chemical) stability as a generic environmental feature responsible for various modes of plankton dynamics, including chaotic behavior. In contrast to experimental studies, until recently abiotic stability in natural estuarine and coastal ecosystems was considered a rare phenomenon, which is particularly difficult to detect and measure. In this study, we aimed at measuring stability of the major physico-chemical parameters in a coastal marine ecosystem and assessing its impact on the algal proliferation. We hypothesized that abiotic stability in natural environments can eventually facilitate HABs. To test this hypothesis, we used the database collected in the southern Baltic Sea coastal waters between 1988 and 2016. We analyzed long-term trends in phytoplankton composition and abundance, with the focus on bloom-forming dinoflagellates. Fifteen dinoflagellate bloom events were registered during the three decades of study; nearly all blooms were dominated by the Prorocentrum species, most often by the mixotrophic P. cordatum. Stability of eleven abiotic characteristics (water temperature and salinity, pH, Secchi depth, concentrations of chlorophyll a, total phosphorus, total nitrogen, nitrite, nitrate, ammonium, and TN/TP ratio) was measured using the ‘synchronized’ and ‘shifted-data’ approaches. Our results verified the proposed research hypothesis and demonstrated that the dinoflagellate blooms were usually bound to higher stability of water temperature, pH, and concentrations of nitrogen compounds. Thus, we showed that abiotic stability, but not just the critical absolute values of the environmental parameters, can induce HABs. However, high adaptability and plasticity of feeding strategies employed by the dominant mixotrophic dinoflagellates hamper the exposure of clear correlations between stability of nutrients concentration and the magnitude of blooms. These findings allow assuming that the ‘paradox of chaos’ – the phenomenon, which was originally discovered in the abiotically stable experimental ecosystems, can also manifest itself in natural sea coastal waters, demonstrating how the complex biotic interactions drive plankton dynamics and promote HABs in the absence of external abiotic triggers.

<span>First researches of the underwater ecosystem communities of an underground channel built in 1950s (Balaklava bay, Sevastopol)</span>

The results of the first studies of the ecosystem state of the underwater part of the channel, artificially created in the middle of the 20th century on the western shore of the Balaklava Bay (Sevastopol) as a naval base of the Black Sea Fleet for the submarines repair, are presented. Channel's ecosystem is determined by uniqueness of anthropogenic formation and considered as analogue of natural Black Sea cave. Hydrospelological survey of the channel and biological studies allowed assessing its current state, the nature of biofouling of its walls and anthropogenic and technical pollution of the bottom. Macrofauna of the channel wall biofouling is represented by the Mytilaster lineatus community, which has a high level of species abundance (about 80 species have been registered) and quantitative development. Both in taxonomic diversity and in quantitative terms, this community is comparable to the rocky substrate community near open Crimean coasts, but with a smaller share of crustacean group development. Due to weakened hydrodynamics, well developed fauna of bryozoans forming plurannual crusty structures and single sponges is observed on the channel's walls. In contrast to the channel walls biofouling, its bottom macrofauna has relatively lower quantitative and qualitative composition. Meiobenthos in the channel’s wall biofouling is represented by 18 higher taxa (type, class, order) of Protozoa and Metazoa with predominance of harpacticoids by abundance. Meiobenthos of the soft bottom of underground channel is represented by 15 higher taxa with predominance of free-living nematodes and harpacticoids by abundance. Average density of meiobenthos in the channel’s bottom sediments is comparable with similar parameters of its development in open water areas and Sevastopol bays.

Alkynyl-Based sp 2 Carbon-Conjugated Covalent Organic Frameworks with Enhanced Uranium Extraction from Seawater by Photoinduced Multiple Effects

Biofouling is a major obstacle to the efficient extraction of uranium from seawater due to the numerous marine microorganisms in the ocean. Herein, we report a novel amidoxime (AO) crystalline cova...

Fluorescence sensing of microplastics on surfaces

Microplastics, nanoplastics and related products have been recently found in marine ecosystems worldwide, calling for new analytical methods for rapid detection and risk assessment. Fluorescence is a sensitive technique that when used with polarity probes can potentially detect low-polarity plastic particles in environments. Here, we evaluated the fluorescence technique to sense polystyrene microparticles directly on salt, silica and sand surfaces, using Nile Red and pyrene as polarity probes. Results show that all probes displayed fluorescence on silica and sand, whereas strong fluorescence quenching was observed on NaCl. Polystyrene particles increase the fluorescence intensity due to probe migration into their nonpolar microenvironment. In the presence of polystyrene, the spectra of Nile Red are shifted to shorter wavelengths, while the ratio of vibronic bands I1/I3 of fluorescence of pyrene decreases to about 1. Pyrene showed similar sensitivity toward surface-modified carboxyl polystyrene particles. On NaCl, the emission of pyrene increases linearly with polystyrene content for concentrations from 0.5 to 20 µg/g. The detection limit of polystyrene microparticles on natural sea salt using pyrene as probe is about 0.2 µg/g, while on sand, the sensitivity is about one order of magnitude lower. Overall, although being of relatively low selectivity, the fluorescence technique can be used to determine a maximum content of plastic particles of few micrometers size with little sample preparation. Fluorescence, when used in conjunction with pyrene probe, allows for detection and quantification of microplastic particles in the sub-ppm range.

Inhibicija korozije legure SS 18/8 u morskoj vodi sistemom Thiourea-Zn2

The corrosion resistance of SS 18/8 in natural sea water, in presence of an inhibitor named Thiourea-Zn2+ has been evaluated. Weight loss method, polarization study and AC impedance spectra have been employed to evaluate the corrosion resistance of SS 18/8 alloy in natural sea water, in presence of an inhibitor named Thiourea-Zn2+ system. Weight loss method reveals that Thiourea-Zn2+ system offers a maximum corrosion inhibition efficiency of 95% in controlling corrosion of SS 18/8 alloy in natural sea water. Synergism parameters are found to be greater than 1, confirming the synergistic effect existing between Thiourea-Zn2+. Adsorption of inhibitor molecules on the metal surface obey Langmuir adsorption isotherm. Polarisation study reveals that the inhibitors named Thiourea-Zn2+ system functions as mixed type of inhibitor. AC impedance spectra confirm the formation of a protective film on the metal surface. This formulation of Thiourea-Zn2+ may be used in cooling water systems where SS 18/8 alloy pipelines are used to carry sea water which is used as coolant. Also, Thiourea-Zn2+ coating can be given on SS 18/8 alloy to protect it from corrosion by sea water when SS 18/8 alloy is used as hull plates in ship industry.

Wpływ przechowywania na parametry jakości soli morskiej

Table salt (sodium chloride) is one of the most commonly occurring compounds on Earth. Sea salt is produced by the evaporation of sea water. Because of its origin, this type of salt is distinguished by a natural content of iodine and other valuable minerals (lithium, magnesium, zinc and selenium). Sea salt has a more distinctive taste compared to table salt, so that smaller amounts thereof can be used and, owing to its relatively low sodium content, it is considered to be the healthiest type of salt. The natural sea salt crystals impede the packaging and storage processes and also its dissolution during the technological process or during the food preparation by consumers in domestic conditions. Thus, the objective of the research study was to assess the effect of storage on the quality parameters of crystalline (commercial) and finely ground sea salt. The research material consisted of 6 sea salt samples, which were assessed in a crystalline (CH) and ground (RH) forms immediately after purchase and after 12 months of storage – crystalline (CP) and ground (RP) sea salt samples. The quality assessment of the sea salt samples was made on the basis of the following: water content and water activity, colour assessment, determination of loose (bulk) and tapped density, and static and kinetic angle of repose measured. On the basis of the analyses performed, statistically significant differences were found between the crystalline and ground salt samples taken from the purchased and stored packets; those differences were found in the L* colour parameter (brightness), the value of the Hausner ratio, and the values of the static and kinetic angle of repose. The performed quality assessment of the stored ground sea salt samples might constitute potential recommendations for both the consumers and the food technologists in various branches of the food industry.

Saltwater corrosion behaviour of equal channel angular pressed AZ80/91 Mg alloys

In this study, AZ80/91 Mg alloys were used to comprehend the electrochemical corrosion behaviour of coarse-grained and fine-grained Mg alloys in different concentration of NaCl solution as well as in the marine environment. The inadequate studies of the corrosion response of ECAPed AZ80 and AZ91 Mg alloy in a different environment were noticed. Accordingly, the current research presents and compares the corrosion behaviour of AZ80/91 Mg alloys in 2.5 wt% NaCl, 3.5 wt% NaCl solution and Natural Sea Water. Influence of corrosion media on coarse and fine-grained AZ80/91 Mg alloys was discussed in the results and discussion section. Corrosion attack of AZ80/91 Mg alloys under the above environment, increased with increase in chloride ion concentration and decreased with the ECAP passes.

Using satellite remote sensing to improve the prediction of scallop condition in their natural environment: Case study for Georges Bank, Canada

The continuous, synoptical and high spatio-temporal resolution of thermal and visible satellite observations constitute an asset when characterizing and monitoring biogeochemical cycles in the oceans. In particular, they provide a unique insight into the hydrodynamics of the surface ocean and phytoplankton phenology. This information can be combined with in-situ observations of higher trophic levels to understand the functioning of the marine ecosystem, with potential use for fisheries and aquaculture. In the Gulf of Maine, off the eastern seaboard of North America, Georges Bank is one of the world's most productive natural sea scallop (Placopecten magellanicus) fisheries, which sustains economically valuable fisheries in Canada and the US. In Canada, the relationship between the scallop meat weight and its shell height (known as scallop condition) is used to obtain biomass estimates for stock assessment and thereby influences the fishing quotas. On Georges Bank, for a 100 mm shell height scallop, scallop condition has varied significantly interannually between 10.2 g and 19.5 g. Establishing a relationship between environmental factors and scallop condition would improve the forecasting of scallop biomass and reduce the uncertainty when determining the total allowable catch for the subsequent fishing season. In this study, satellite remote-sensed sea-surface temperature (SST) and chlorophyll-a concentration (Chla) coupled with in-situ measurements of scallop condition (SC) on Georges Bank were used to assess the relationship between SC and satellite-derived environmental conditions between 1985 and 2019 for SST and between 1998 and 2019 for Chla. The inter-annual variation of SC in May was found to be positively correlated (p-value <0.001) with the variation in SST in winter-spring months of the current and previous year of the SC survey. An empirical linear model for the estimation of SC was developed and validated using two independent datasets of satellite SST (r2 = 0.64, MAPD = 7%). Another model using cumulative SST in the previous year only was also provided (r2 = 0.58, MAPD = 7.7%), which could serve as an alternative choice when the SST products in the current year are not yet available for use. There was a weak relationship observed between SC and Chla; this is likely due to the influence of water-column vertical mixing on transport of phytoplankton to the benthic zone where the sea scallop resides. Our study indicates that a cost-effective satellite-derived SST product can be used to improve predictions of SC and provide useful information and decision support tools for managing scallop stocks.