Marine Renewable Resources Research Articles

Sheared turbulent flows and wake dynamics of an idled floating tidal turbine

Ocean energy extraction is on the rise. While tides are the most predictable amongst marine renewable resources, turbulent and complex flows still challenge reliable tidal stream energy extraction and there is also uncertainty in how devices change the natural environment. To ensure the long-term integrity of emergent floating tidal turbine technologies, advances in field measurements are required to capture multiscale, real-world flow interactions. Here we use aerial drones and acoustic profiling transects to quantify the site- and scale-dependent complexities of actual turbulent flows around an idled, utility-scale floating tidal turbine (20 m rotor diameter, D). The combined spatial resolution of our baseline measurements is sufficiently high to quantify sheared, turbulent inflow conditions (reversed shear profiles, turbulence intensity >20%, and turbulence length scales > 0.4D). We also detect downstream velocity deficits (approaching 20% at 4D) and trace the far-wake propagation using acoustic backscattering techniques in excess of 30D. Addressing the energy-environment nexus, our oceanographic lens on flow characterisation will help to validate multiscale flow physics around offshore energy platforms that have thus far only been simulated.

Facile Synthesis of Silver Nanoparticles From Sustainable Sargassum sp. Seaweed Material and Its Anti-inflammatory Application.

Background Sustainable and environmentally friendly methods of producing nanoparticles are now being investigated by scientists. Because there are so many marine renewable resources, scientists are focusing their attention on studying seagrass, seaweed, mangroves, marine macroalgae, and microalgae. An exciting new frontier in research involves the synthesis ofnanoparticles using extracts from seaweed. Seaweed extracts are utilized to synthesize silver nanoparticles (Ag NPs), which serve as both reducing and stabilizing agents. Seaweed extracts possess bioactive substances like proteins, polysaccharides, and polyphenols that enable them to effectively convert silver (Ag+) ions intoAg NPs.Ag NPs derived fromSargassum seaweed have played an essential role in improving the anti-inflammatory properties of seaweed extracts. This study aimed to investigate thebiosynthesis of Ag NPs fromSargassumseaweed and evaluate their anti-inflammatory properties. Materials and methods About 50 g of seaweed samples were mixed with 100 mL of distilled water and stirred for 24 hours. Additionally, 1.2g of silver nitrate (0.120 M) was dissolvedin 60 mL of distilled water to make a silver (Ag) solution. A 60 mL solution of silver nitrate (AgNO3) was mixed with a 40 mL solution of seaweed extract in water, and the mixture was stirred with a stirrer for 24 hours.A UV spectrophotometer was used to regularly monitor the reduction ofAg+ ions in the solution. Ag NPs were purified using a sequence of centrifugation steps with a duration of 10 minutes at a speed of 2500 revolutions per minute (rpm). To remove moisture from the water-suspended nanoparticles, they were vacuum-dried for 24 hours. Results The synthesis of Ag NPsfrom seaweed extract resulted in a noticeable change in the color of the mixture, which went from pale to brown. The alteration in color signifies the reduction of AgNO3 to Ag+ ions, facilitating the creation of Ag NPs. X-ray diffraction (XRD) measurement verified the remarkable crystallinity of the synthesized Ag NPs. Field emission scanning electron microscopy (FESEM) images indicated a spherical, homogeneous structure. The Ag NPs derived from seaweed exhibited significant anti-inflammatory characteristics. Conclusion Utilizing Sargassum sp. seaweed in the biological synthesis of Ag NPs shows promiseto develop nanomaterials that canexhibit anti-inflammatory effects. This technique has benefits, such as being environmentally friendly and cost-efficient. Additional research in this area is essential for effectively exploiting the potential of Ag NPs in anti-inflammatory activity.

On the complementarity of wave, tidal, wind and solar resources in Ireland

The use of renewable energy sources has been recognised as a key strategy for combating anthropogenic climate change. These energy sources are regarded as sustainable because they are naturally replenished and do not produce greenhouse gases. A vital step in achieving a low-carbon economy and addressing the global challenge of climate change is the implementation of renewable energy alternatives. This “green revolution” has been led by solar and wind energy. Incorporating new forms of renewable energy resources, such as wave and tidal energy, into the current mix of resources will aid in the transition to a fully 100% renewable energy future due to the abundance of such resources [1]. The complementarity assessment of renewable energy resources is crucial to design the optimal mix of these resources to meet load requirements in a jurisdiction. Multiple studies in the literature discuss the complementarity of renewable energy modalities for different jurisdictions. A review of such studies is presented in [2]. The review shows that most of these studies focus on wind, solar and hydro-power generation, with most focusing on just two of these three modalities. However, recent efforts have been made to assess the temporal complementarity of more than two resources, including marine renewable energy resources (wave and tidal) for US and UK jurisdictions [3], [4], concluding that marine renewable resources may have significant value to a future power system in terms of reduced balancing requirements and valuable capacity contribution. Similarly, Ireland may enjoy similar benefits from combined resource exploitation due to its island topography and good marine resource. Fig. 1, by way of example, presents renewable resource generation profiles (hourly resolution) for four seasonal weeks in 2017 and illustrates the potential benefits of combining marine resources at Inishtrahull Sound, Ireland. For example, wind and tidal are low in the autumn week (highlighted section), while wave and solar resources are available. However, the summer week sees low wind and wave resources, while tidal and solar provide complementary benefits. Another critical aspect of the complementarity studies is the set of metrics and indices used to assess the complementarity. Such metrics and indices are reviewed in [5]. Correlation coefficients are commonly used in the literature to evaluate complementarity between energy sources. However, there are several issues related to the correlation metrics reported in the literature, including the inability to handle nonlinearities in the data and the inability to handle more than two resources [6], to name a few. 
 In this paper, we present a complementarity assessment of the four renewable resources, i.e. wave, tidal, wind and solar, around the island of Ireland (including Northern Ireland) using the new complementarity indices based on the mathematical concept of the total variation [6], which allow for complementarity assessment of more than two resources. We also comment on the possible benefits of the temporal characteristics of the marine renewable resources on the Irish generation mix. 
 
 Please see attached file for Figures and references.

Novel Hybrid Floating Breakwater- Wave Energy Converter Device: Preliminary Experimental Investigations

The marine space is increasingly gaining ground as the ideal candidate to drive the energy economic sector as it hosts a huge amount of natural resources to be exploited, such as waves, wind, and solar irradiation. Innovative devices harnessing these marine renewable resources have been thought to be assembled in a new concept of an energy hub for the Mediterranean Sea, recently proposed by the National Research Council of Italy.
 The feasibility of this floating energy archipelago is strongly dependent on the creation of a protected sea area with reduced wave heights, where to safely install new types of floating devices for energy harvesting from the sea, like solar islands.
 For this purpose, a floating breakwater module has been specifically designed to surround the archipelago with one or more rows. Moreover, investigating the possibility to implement a dual and alternative use of this floating module, as a traditional dissipative system and wave energy converter has resulted in an extremely challenging task. With respect to the existing hybrid floating breakwater-Wave Energy Converters in fact, the novelty of this device is the optimization of both functionalities by varying its draft.
 In extremely rough seas, the hybrid module should only serve as a passive breakwater, soaking up incoming waves and safeguarding the equipment installed inside the archipelago. Otherwise, the floating module should operate as a WEC in more frequent mild sea states, assisting the archipelago's energy output. The whole produced energy can be stored and used to supply the development of new productive activities, such as aquaculture, the expensive process of seawater desalination, as well as the production of low environmental impact fuels like methanol or hydrogen.
 The model's dual functionality is accomplished by different draft values. This parameter is directly influenced by the volume of water pumped into the module, which raises the floater's displacement. The module is almost completely immersed in the first scenario, which simulates breakwater functioning, increasing the device's stability and the amount of reflected and dissipated waves. On the other hand, when the module exhibits WEC behavior, a lower displacement is necessary, allowing greater device motions, able to better exploit the energy of the waves.
 In this study, preliminary results obtained from an experimental campaign carried out on a 1:10 Froude-scaled model are reported. In particular, the dynamic behaviour of the hybrid device is evaluated in terms of response amplitude operators, while the attenuation performances are condensed in the transmission coefficient which indicates the reduction of the wave height inside the archipelago.

Research on the Design Problem of Maximum Wave Energy Output Power

With the development of economy, energy and environment problems have become a big problem in today's society. To realize sustainable development and protect ecological environment has become the consensus of all countries in the world. Wave energy, as an important Marine renewable resource, is more widely distributed than conventional energy, with abundant energy storage and considerable application value. In this paper, based on the analysis of the heave and pitch motion of the wave energy device in seawater, the motion states of the float and vibrator from static to heave and pitch motion are obtained through the force analysis of the float and vibrator and the establishment of differential equations. The maximum output power of the wave energy device is analyzed and discussed by adjusting the damping coefficient of the damper and other related parameters.

Is the Small-Scale Fishery more sustainable in terms of GHG emissions? A case study analysis from the Central Mediterranean Sea

Small-Scale Fishery (SSF) is recognized as one of the more sustainable among the activities currently exploiting marine renewable resources. This is mainly due to the use of fishing gears characterised by a low environmental impact and a high selectivity. However, there is still room for improvement when analysing the sustainability of SSF sector. Within this context, Greenhouse Gases (GHG) emissions – CO2 in particular – are one of the most relevant aspect to be considered. In particular, fuel consumption and its reduction represent the main issue when discussing sustainability, especially to cope with climate changes. In this paper, the first inventory of CO2 emissions from the SSF vessels in the Central-Northern Adriatic Sea (GSA17) has been compiled, based on data collected from SSF operators, validated by means of a geospatial-based method. Emission intensity estimates – 7.01 kg of CO2 emitted per kg of landing or 2.08 kg of CO2 emitted per € of landing – confirmed the lower values by SSF vessels in comparison with other fleet segments. Results are discussed in the light of the mitigation of GHG emissions for the SSF, considering the technological features of Adriatic SSF, fishers’ behaviour and an improved management of the fishery.

Research on wave energy collection based on swing ship triboelectric nanogenerator

Wave energy has the advantages of huge energy storage and high energy flow density, and it is one of the most promising Marine renewable resources. In this paper, a design method based on swing ship type triboelectric nanogenerator (ST-TENG) is proposed to collect low-frequency wave energy. This swing ship type TENG (ST-TENG) contains three sets of triboelectric nanogenerator, consisting of internal and external ship type devices with pasted electrodes and independent rollers. Combined with the power generation theory of two working modes of free-standing layer and vertical contact separation and COMSOL electrostatic simulation, the operating principle of the device is clarified. Through the rolling of the roller in the built-in ship and the swing of the built-in ship, the wave energy can be effectively collected and transformed into electric energy. In addition, through the comparative experiment, the influence of different influencing factors on the output performance of ST-TENG is quantitatively analyzed. The experimental results show that for the internal structure parameters, ST-TENG has the best output capacity in the case of polytetrafluoroethylene (PTFE) with thickness of 0.3 mm, solid cylinder and adding foam tape. Under external working conditions, 1.5 Hz is closest to the resonant frequency of the ST-TENG, and the amplitude increases from 30 mm to 60 mm, which improve the power generation performance. In addition, ST-TENG can illuminate at least 100 LEDs under normal conditions and quickly charge different capacitors to a certain voltage. Therefore, the design of ST-TENG provides new ideas for large-scale blue energy collection.

Review of wave power system development and research on triboelectric nano power systems

With its huge energy storage and high energy density, ocean wave energy is one of the most promising marine renewable resources. Traditional wave energy generation technology, on the other hand, has a high maintenance cost, a bulky construction, and a low conversion efficiency, which limits its application. Due to its low cost, simple construction, and ease of fabrication, wave energy generating technology based on triboelectric nanogenerators has emerged as a potential new power generation technology in recent years. This paper elaborates on the power generation principle, working mode, and the latest research status of wave energy harvesting using different types of triboelectric nanogenerator structures, and finally summarises the current problems and challenges of this technology, and innovatively combines some current examples to propose future research trends, which can help relevant reseach. This will assist researchers in swiftly grasping the present state of wave energy harvesting research and promoting the field’s progress.

Pentapeptide AYP from Isochrysis Zhanjiangensis Exhibits Antiangiogenic Activity in HT1080 Cells and HUVECs by Suppressing Migration and Invasion In Vitro.

Microalgae are important biological sources of marine active peptides and renewable biological resources. Isochrysis zhanjiangensis has been widely used in biological ultrafiltration membranes and aquaculture. However, there are relatively few studies on its component structure and diverse activities. In this study, the mechanism of action of previously isolated pentapeptides (AYP, Ala-Tyr-Ala-Pro-Glu) on inflammation and tumor angiogenesis was evaluated. The results showed that AYP could effectively inhibit the invasion and migration of human umbilical vein endothelial cells (HUVECs) and HT1080 cells by downregulating the expression of MMP-2/-9, independent of cytotoxicity. Especially after 100 μM AYP treatment, the ability to inhibit migration was about 67.7% ± 1.9 for HT1080 cells and 63.6% ± 1.3 for HUVECs, respectively. In addition, the activity of iNOS and COX-2 was decreased by inhibiting the oversecretion of VEGF in HT1080 cells induced by CoCl2 and the activation of VEGFR-2 in HUVECs and by regulating PI3K/AKT and Ras/MAPK signaling pathways. It can prevent inflammation and block tumor angiogenesis. Therefore, AYP is expected to become a drug or functional food to prevent and treat tumor angiogenesis.

A Short Overview: Marine Resources as Potential Interventions for the Omicron SARS-CoV-2 Variant

In November of 2021, a recently evolved variant of SARS-CoV-2, omicron, was discovered. In just one month, omicron has spread to more than 89 countries resulting in a rapid rise in cases and a new wave of infections. With over 46 mutations, omicron brings concern to the public health and may be able to infect at a greater capacity than previous strains. Although able to infect double vaccinated and previously infected individuals, the booster vaccine may prove promising. However, more research is needed to fully elucidate the key function of each mutation and to better develop effective drugs. Marine resources may be a promising drug discovery avenue to investigate. For example, compounds such as natural bromotyrosines and inorganic polyphosphate have been shown to have multiple mechanisms of action against viruses, like SARS-CoV-2. Through viral entry blockade and preventing viral replication and protein synthesis, metabolites produced from marine organisms may be promising against the evolving SARS-CoV-2. The present review highlights key features of the omicron SARS-CoV-2 variant, summarizes key studies and reports on omicron viral infection and examines the potential for intervention using renewable marine resources.

Experimental investigation of motion behavior in irregular wave and site selection analysis of a hybrid offshore renewable power station for Egypt

The majority of the population living in coastal remote areas does not have access to energy sources in Egypt. Development of living standards in such areas without infrastructure can be achieved through floating power stations. Novel cylindrical power station powered by hybrid marine renewable resources is proposed to overcome energy shortage in such areas. The objective of the present study is to experimentally evaluate the motion behaviour of the proposed concept in different load conditions for critical environmental loads in order to obtain model characteristic data which is critical in the structure's verification and other post-analysis study. Furthermore, selecting suitable deployment site for the proposed concept was performed based on integrated geographical information systems and multi-criteria decision model considering the potential of renewable sources in Egypt. The experimental test was conducted using 1:100 model-scale in irregular wave which is a more realistic condition in order to check the operational safety among critical conditions. The site selection analysis show that Marsa Alam area has the highest priority to place the proposed concept. Moreover, the time-domain analysis results indicate that the proposed concept can safely operate in the selected deployment area subjected to environmental loads.

Hydrodynamic and Morphodynamic Influences from Ocean Current Energy Conversion Sites in the South–Southeastern Brazilian Inner Shelf

As marine renewable resources begin to become a feasible energy source, it becomes crucial to investigate the nearshore impact of hydrodynamic and morphodynamic processes. As part of the implementation of turbines in the numerical modeling environment of Telemac-3D and Sisyphe modules, we conducted a 10-year run to evaluate nearshore impacts of turbines in the flow. We used five criteria to define viable locations. Turbines sites were added to a conversion energy model coupled into the hydrodynamic model in order to develop properly the flow changes towards the energy conversion process. The results revealed that in the three chosen spots, turbines were not converting equally the current energy within the site. In fact, the turbines located on the outer side of the farm developed greater conversion rates. This impacted the nearshore in the following ways: (1) the decrease in the currents intensity that generates strong adjustments in the water column, breaking the natural pattern of vertical circulation; (2) development of lateral flows that in time affects the bottom dynamics and results in changes in sediment deposition; and (3) increase in bedload transport rates around the turbine’s field due to divergence in the flow. The idealized turbines sites produced 1,775 GWh in 10 years, which could provide electricity to 54,181 residences during this period.

Artisanal Marine Fisheries and Climate Change in the Region of Lima, Peru

This study explores the relationship between climate change and artisanal marine fisheries in the region of Lima, Peru. From the perspective of the economics of climate change and renewable marine resources, the methods of correlations and bivariate regression are employed. A negative relationship is found between the increase in the sea surface temperature (SST) and the marine fishery catches landed at the ports of the Lima region (2004-2017).The higher the SST, the lower fishing effort. It was also found that the SST significantly influences the gross added value of fishing. To reduce the vulnerability of artisanal marine fisheries, the main adaptation measures that should be implemented as public policy are accessible loans for artisanal fishers vulnerable to climate variability, a reduction in polluting emissions discharged by industrial fisheries into artisanal fishing grounds for direct human consumption, and adaptation projects.

Estimation of ocean thermal energy potential in the Aguni Basin

As a marine renewable resource, ocean thermal energy conversion (OTEC) is gaining attention because of its sustainability and environment-friendly characteristics. The thermal energy potential in the open ocean has been well documented in the previous literature. However, regional potential near the coast is not easily estimated using methods and parameters for global estimation. This study estimates the thermal energy potential of the Aguni Basin in the East China Sea using a high-resolution ocean model. An additional simulation without tide is performed to clarify the tidal effect. The results show that two traditional methods overestimate the OTEC power density in the Aguni Basin, while two other approaches are able to improve the estimation. The OTEC power density in the Aguni Basin is much larger than that in the global ocean, largely owing to vigorous tidal mixing. Strong and sustainable power generation is possible near the northeastern slope of Kumejima Island as a result of the high OTEC power density within a short distance to the coast.

Seaweed Biodiversity of India: Reviewing Current Knowledge to Identify Gaps, Challenges, and Opportunities

Seaweeds are a renewable marine resources and have not yet received considerable attention in the field of taxonomy in India as compared to their terrestrial counterparts, essentially due to the lack of awareness of their economic potential. Although the recent inventory from the Indian region documented the presence of approximately 865 seaweed taxa, of which only a few are taxonomically well characterized, more precise information still awaits with respect to microscopic and molecular examinations of many. Thus far, in terms of spatial extent, probably only a few of the total hospitable seaweed habitats have been explored, and large portions, including island territories and subtidal waters, remain virtually untouched. Surveying those may lead to the reporting of several taxa new to science. Furthermore, more focused efforts are required to understand the endemic and endangered taxa which have high conservation implications. Considering the unprecedented pressures seaweeds are facing, including coastal pollution and human-induced global warming, it is critical to reinforce our knowledge of seaweed biodiversity. In the present communication, we intended to address the status of seaweed biodiversity in India along with the gaps, challenges, and opportunities.

Construction of β-FeOOH@tunicate cellulose nanocomposite hydrogels and their highly efficient photocatalytic properties.

The environmentally friendly materials fabricated from renewable marine resources have aroused worldwide concerns. Here, for the first time, tunicate cellulose was dissolved in LiOH/urea aqueous solution at -12 °C after ball-milling, and its molecular weight was determined with laser light scattering. Hydrogels were fabricated from the cellulose solution by regenerating in ethanol, and β-FeOOH nanoparticles (NPs) were in-situ synthesized to obtain β-FeOOH/cellulose composite hydrogels (TCH-Fe). The tunicate cellulose hydrogels (TCH) not only disperse uniformly and immobilize firmly the β-FeOOH NPs, but also acted as structural materials for continuous flow photocatalytic system. The photocatalytic degradation of methylene blue (MB) over TCH-Fe achieved up to 99.89% in 30 min under visible-light irradiation, and maintained as high as ∼98% after treatment for 8 h, indicating a highly efficient photodegradation of MB. We provided a low-cost and facile method to construct new sustainable materials derived from marine biomass with highly efficient photocatalytic properties.

Efficient production of poly γ-d-glutamic acid from the bloom-forming green macroalgae, Ulva sp., by Bacillus sp. SJ-10.

Numerous studies on poly γ-d-glutamicacid (γ-PGA) production have investigated terrestrial renewable sources for reducing production costs, but there are no studies using waste marine resources so far. We aimed to develop a cost-effective production method of γ-d-PGA by Bacillus sp. SJ-10 using green macroalgae (Ulva sp.) as a major substrate without hydrolysis pretreatment. The SJ-10 was shown to not only cause immediate tissue degradation of the Ulva membrane but also grew well as a sole substrate. The γ-d-PGA yield was 6.29 ± 0.34 g/L under optimized conditions via the response surface method, and the produced γ-d-PGA had a thermal decomposition temperature of 310°C and molecular weight of 250-1780 kDa. The calculated cost efficiency for the final yield was 32% when compared with complex media. Therefore, the present study provided a strategy for promoting an ecofriendly and cost-effective means to produce γ-d-PGA via a marine renewable resource.

Women Enterprising in Seaweed Farming With Special References Fisherwomen Widows in Kanyakumari District Tamilnadu India

Seaweeds are not weeds as the name implies. But they are the renewable marine resources of value, growing well in shallow waters where suitable substratum for its growth exists. They are exploited from the south east coast of Tamil Nadu from Mandapam to Kanyakumari, Gujarat Coast, Lakshadweep islands and the Andaman and Nicobar Islands and few other places like Chilka and Pulicat. Seaweed collection renders extensive employment to the coastal fisher folk. The estimation of seaweed resources indicate that only a negligible quantity is harvested. At present nearly 5000 women depend on the seaweed industries for their livelihood. If the available resources are harvested to its optimal level, it can provide employment to another 20,000 coastal fisher folk in harvesting sector and an equal number in post-harvest activities. Since the domain of seaweed collecting industry is mainly dominated by women, special efforts should be taken for its optimum exploitation and market expansion through diversified product development and their popularization. Seaweed mariculture offers an economically sustainable livelihood option for fisherwomen, who, with little effort can contribute significantly to the household income. Today seaweed cultivation techniques have been standardized, improved and made economically viable. Corporate backed by institutional and financial support led to the expansion of seaweed farming, through Self Help Groups (SHG) model (mostly women). This paper deals with the employment potential of fisher women in seaweed industries and to evaluate the economic performance of seaweed farming, including the empowerment of fisherwomen widows in Muttom, Kanyakumari District of Tamil Nadu, India.

Marine Currents Energy Resource Characterization for Morocco

Over the last two decades, there has been a great interest in marine renewable energy exploitation (70% of the globe are ocean) due to the limitation of fossil resources and the effect of climate change. The marine current energy constitutes a huge potential of marine renewable resources for producing electricity using a Hydrokinetic turbine. the assessment of the potential resources of sites is the most necessaire step to select the adequate location for implementing and choosing the corresponding conversion systems. The main objective of this work is to calculate and map with a high resolution (200 m) the current velocity of some Moroccan sites in order to select the items with high resource potential. In this sense, the current velocity was calculated using the 3D dimensions’ hydrodynamic numerical model SWAN. In addition, the accurate data of Copernicus center with have been employed with the SWAN parameters to perform the high potential. The results obtained show the potential of the sites selected to facilitate the choice of the adequate technology which can be employed to extract the kinetic energy of the marine current.

Optimization of physicochemical parameters in the biofabrication of gold nanoparticles using marine macroalgae Padina tetrastromatica and its catalytic efficacy in the degradation of organic dyes

Green synthesis of metallic nanoparticles by means of renewable bioresources has emerged as a new trend in current nanotechnology research with improved environmental safety. In the current study, monodispersed gold nanoparticles (AuNPs) with excellent stability were prepared in a completely green and cost effective manner using aqueous extract of marine macroalgae-Padina tetrastromatica. The influence of reaction conditions such as the quantity of seaweed extract, temperature, precursor metal ion concentration, reaction time and pH on the biosynthesis of nanoparticle was evaluated spectroscopically and also with the help of high resolution transmission electron microscopy (HR-TEM). These physicochemical parameters not only affected the rate of formation but also the size and morphology of resultant nanoparticles. Optimum conditions resulted in the generation of nearly spherical AuNPs having an average particle size of 11.4 nm. The high crystallinity of the biogenic AuNPs was confirmed from characteristic diffraction peaks in XRD profile, clear lattice fringes in the HR-TEM image and bright circular spots in the SAED pattern. The presence of metallic gold was evidenced from EDAX profile. FTIR study revealed the role of secondary metabolites in the bioreduction as well as stabilization of AuNPs. The study also highlights the spectroscopic investigation on the catalytic efficacy of the biosynthesized AuNPs in the reduction reactions of hazardous organic dyes, eosin yellow and Congo red using sodium borohydride, which have a pseudo-first order kinetics. Thus, the biosynthesized metal nanoparticles using renewable marine resources like seaweeds act as promising materials for the application in environmental protection.Graphical abstract