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Strong seasonal upwelling, downwelling, changes in current patterns and the volume of freshwater discharge from Cochin Estuary defines the coastal waters off Cochin. These coastal waters were investigated through monthly sampling efforts during March 2015 to February 2016 to study the seasonal and spatial variability in bio-optical properties for the four different seasons mainly Spring Inter Monsoon (SIM), South West Monsoon (SWM), Fall Inter Monsoon (FIM) and Winter Monsoon (WM). The Barmouth region is the meeting place where freshwater from Cochin Estuary directly enters to the sea through a single narrow outlet, was dominated by highly turbid waters during the entire period of study. Among the four seasons, chlorophyll a (Chl_a) concentration showed a high value during SWM, ranged from 2.90 to 11.66 mg m −3 with an average value of 6.56 ± 3.51 mg m −3. During SIM the distribution of coloured dissolved organic matter (CDOM) is controlled by decomposition of phytoplankton biomass and the river discharge, whereas during SWM the temporal distribution of CDOM is controlled only by river discharge. The highest value for CDOM spectral slope (S CDOM) was observed during SWM, ranged from 0.013 to 0.020 nm −1 with an average value of 0.015 ± 0.002 nm −1. During WM, the high S CDOM with lower a CDOM (443) indicates the photo-degradation affects the absorption characteristics of CDOM. The observed nonlinearity between Chl_a and the ratio of phytoplankton absorption a ph (443)/a ph (670) indicating the packaging effect and changes in the intercellular composition of pigments. During the study period, a ph (670) was strongly correlated with Chl_a than a ph (443), which explains the accessory pigment absorption dominating more than Chl_a in the blue part of the spectrum. Similarly, the results obtained from seasonal bio-optical data indicating that Chl_a significantly contributes light attenuation of the water column during SIM, whereas detritus (a d) significantly contributes light attenuation during SIM and WM. During the study period, the relative absorption of detritus materials dominates the relative absorption of phytoplankton and CDOM at 443, 555 and 670 nm wavelengths.

Diversity studies of endophytic assemblages are emerging challenges, which unveil novel phenotypes producing interesting chemical entities and a better understanding of their ecological significance. In the present investigation, we selected an extremely complex and unique environment supporting unexplored endophytes, ‘Macroalgae of Kerala coast, India’. Unlike terrestrial flora and mangroves, reports displaying endophytic assemblages of marine flora remain limited, especially from India. The main goal of this study was to expose hidden endophytic fungi from macroalgae and examination of their bioactive potential. An ecological investigation of four red, four green and three brown algae resulted in 133 fungal taxa with 29 distinct morphospecies. Aspergillus and Penicillium were found to be the dominant genera. Penicillium chrysogenum was the sole fungi that contributed 11% of the entire endophytic community. Antimicrobial activity against various aquaculture/human pathogens revealed that around 59% of endophytes inhibited at least one of the pathogens screened. The maximum number of isolates (37%) inhibited Escherichia coli tailed by Aspergillus fumigatus (27%). Antimicrobial profile of fungal endophytes endorses them as a potential source of bioactive molecules that can be explored to find a solution for drug resistance in microbial pathogens.