Seaweeds are regarded as one of the valuable coastal resources because of their usage in human food, cosmetics, and other industrial items. They also play a significant role in providing nourishment, shelter, and breeding grounds for fish and many other sea species. This study introduces a newly developed seaweed enhancing index (SEI) using spectral bands of near-infrared (NIR) and shortwave infrared (SWIR) of Landsat 8 satellite data. The seaweed patches in the coastal waters of Karachi, Pakistan were mapped using SEI, and its performance was compared with other commonly used indices - Normalized Difference Vegetation Index (NDVI) and Floating Algae Index (FAI). The accuracy of the mapping results obtained from SEI, NDVI, and FAI was checked with field verified seaweed locations. The purpose of the field surveys was to validate the results of this study and to evaluate the performance of SEI with NDVI and FAI. The performance of SEI was found better than NDVI and FAI in enhancing submerged patches of the seaweed pixels what other indices failed to do.

In this work, we report the engineering of a sub-70 nm nanocomposite of ZnO/Zn2TiO4 using a low-temperature solution-phase method. Titanium isopropoxide and zinc acetate were used as precursors, and isopropyl alcohol and water were used as solvents. The investigation focused on the growth of nanocomposites by varying the concentrations of precursors and surfactants, as well as their efficiency within different pH ranges. All three ZnO/Zn2TiO4 nanocomposites consist of hexagonal wurtzite ZnO and Zn2TiO4 structures in the three nanocomposites. The crystallite size in three ZnO/Zn2TiO4 nanocomposites, with a hexagonal wurtzite ZnO structure, were measured to be 62.67, 40.34, and 39.50 nm. The crystallite size values in three ZnO/Zn2TiO4 nanocomposites were 26.15 nm, 25.36 nm, and 21.24 nm, respectively, with Zn2TiO4. Morphological observations, conducted using FESEM, reveal the formation of three ZnO/Zn2TiO4 nanocomposites across the entire sample. These nanocomposites resemble dispersed cotton packets, with sizes ranging from 18 to 350 nm. Peaks in the range of 610-1250cm-1 are attributed to Ti-O bond formation and peak located at 1350-1450 cm-1 are attributed to Zn-O bond formation. Also, EDX spectrum reveals peaks for various sample components such as Ti, O and Zn. UV spectrums confirmed the formation of three nanocomposite of ZnO/Zn2TiO4 as showing two peaks for each sample. Photocatalytic investigation carried out by analyzing the UV-Visible absorption spectra of methylene blue dye on the surface of ZnO/Zn2TiO4 nanocomposites, dye degradation at various irradiation time intervals, dye degradation at varied catalyst concentrations and the influence of pH on dye-degradation. Furthermore, the said nanocomposites were used to degrade environmental pollutant (Methylene blue dye). Different sets of experiments were conducted under ambient conditions which show an excellent photo catalytic degradation efficiency.