RESUMEN
The effects of growth and reproduction on the marine Cyclops sp. were investigated using three microalgae as diets. The development period of Cyclops sp. was evaluated at 106 cells/ml in 15ppt salinity to identify the stationary phase. The survival rate of marine Cyclops from nauplius to adult differed according to the microalgal diet. The results showed that the shortest time (14 days) and highest survival (17.6 ± 0.131 %) for Cyclops sp. was achieved with those fed with Nannochloropsis sp. Whereas, it took longest time (37 days) and lowest survival rate (6.40 ± 0.035 %) when fed Chlamydomonas sp. The developmental period from naupli (I - VI) (6.91 ± 0.453 days), copepodite (I - VI) (11.4 ± 0.311days) and naupli to adult (20 ± 1.08 days) appeared significantly longer when fed with Nannochloropsis sp. compared to other treatments. The daily mean naupli production of adult females over 7 days was significantly higher (p Ë 0.05) in Nannochloropsis sp. compared with Chlamydomonas sp. and Gonyostomum sp. On the 25th day of Nannochloropsis sp. treatment, 99 % of the mature females died. Production (naupli, copepodite adult male and adult female) was significantly higher (p Ë 0.05) in Nannochloropsis sp. than in other microalgal diets. On the fifteenth day, Nannochloropsis sp. showed a significantly higher (p Ë 0.05) specific growth rate than other microalgal diets. Nannochloropsis sp. had the highest nauplius survival rate on the sixth day compared to other microalgal diets. With Nannochloropsis sp., the species has a higher hatching rate, and in Chlamydomonas sp. hatching occurs earlier. The average lifespan for Nannochloropsis sp. was 46 days, for Chlamydomonas sp. it was 37 days, and for Gonyostomum sp. it was 32 days.
RESUMEN
Over recent decades, coastal and marine tourism has significantly contributed to the degradation of coastal features and ecosystems. This study employs the Integrated Valuation of Ecosystem Services (ES) and Trade-offs (InVEST) software to assess the impact of nature-based tourism activities over 13-year periods, particularly focusing on the exposed coast of Bangladesh where most touristic activities occur. The visitation rate from the InVEST model showed a gradual increase from 2005 to 2012, followed by a decline until 2017. The western coast recorded a visitation rate ranging from 1 to 72 (low to moderate), while the eastern coast ranged between 16 and 343 (moderate to high). The real-time data of visitation rate (RTD) for the Sundarbans generally aligns with the model outputs, although occasional irregularities exist in certain years, attributed to local geomorphological inaccessibility and technological limitations. Along the central coast, the visitation rate varied from 2 to 50 (low rate) Photo-User Day (PUD) index. The findings offer valuable insights for future policymaking, facilitating the effective management of tourist sites and promoting sustainable blue economic development in this diverse and vulnerable exposed coastal zone.
RESUMEN
This paper presents the data on growth performance of marine Chlorella sp. cultured in different cost-effective media including cow dung, cow urine, poultry litter, compost, NPK (nitrogen, phosphorus, and potassium), and UTR (Urea, TSP, and red potash). Growth curve of Chlorella sp. was determined at 5 mg of cow dung, poultry litter, compost, NPK, UTR and 5 µL of cow urine per 350 ml sea water (25 ppt) to identify the onset of stationary phase. Further four media among these were selected to continue the experiment at 8 mg and 11 mg of concentration. The higher cell densities were 4.21 × 106 and 4.18 × 106 cells/mL for NPK at 8 mg and 11 mg of concentration on 6th and 5th day, respectively. Cow dung with an 11 mg of concentration exhibited 2.67 × 106 cells/mL on the 3rd day, which is around 1.5 times greater than the highest growth in the same concentration of poultry litter. Chlorella sp. had a higher cell density in NPK media than in other media, however it was discarded since it is inorganic and costly. Due to the low cell density in cow urine media and the prolonged stationary phase in poultry litter media, the focus of the subsequent study was then placed on cow dung media. The data will contribute to the selection of locally available and cost-effective culture media by determining the stationary phases for specific microalgal species which will replace the costly and labor-intensive commercial media.
RESUMEN
BACKGROUND: The ability of many bacteria to adhere on the host surfaces and forming biofilms has major implications in a wide variety of industries including the food industry, where biofilms may create a persistent source of contamination. In the same environmental condition, the multiple bacterial species can closely interact with each other and may easily enhance their drug resistance capability, which finally increases the multi-drug resistant (MDR) attribute of the species. OBJECTIVE: The present study examined whether the mixed-species biofilm possesses any impact on the enhancement of the antibiotic resistance of the planktonic or single-cell bacterial isolates present in the fish samples. METHODS: In this regard, Cyprinus rubrofuscus (Koi), Heteropneustes fossilis (Shing) and Mystus vittatus (Tengra) fishes were collected and subjected to form an in vitro biofilm by shaking condition into the wise bath. The drug-resistant pattern was determined by the Kirby Bauer technique. RESULTS: All the samples exhibited a huge array (up to 107 cfu/ml or g) of bacteria such as E. coli, Klebsiella spp., Vibrio spp., Salmonella spp., Proteus spp. and Staphylococcus spp. The isolates from both the bulk samples and their corresponding biofilms were subjected to antibiogram assay using antibiotics such as Ampicillin (10 µg), Erythromycin (15 µg), Streptomycin (STP 10 µg), Oxacillin (10 µg), Nalidixic acid (30 µg). Before biofilm formation, few of the isolates were found to be sensitive and few were resistant against the antibiotics. But when the species were isolated from the biofilm the sensitive one acquired drug resistance and resistant strain unveiled more resistance towards the same antibiotics. The present study revealed extensive bacterial contamination in fish samples among those some were resistant against the supplied drugs. CONCLUSION: After the formation of multi-species biofilm, the isolates became more resistant against the same drugs that is alarming for consumers and major obstacles to maintain sustainable health.