Distributions of environmental parameters and fish at Humbold Bay, Jayapura

Research on the distribution of fish and plankton in waters that are equipped with environmental parameters is needed to obtain maximum results and increase accuracy also it provides comprehensive information. The research, which was conducted in Humbold Bay, aimed to map the fish and plankton distribution data both vertically and horizontally and combine it with environmental parameters in the bay. Fish and plankton’s data was the volume backscattering strength (Sv) value obtained using the SIMRAD EK-15 device while environmental parameter data, such as temperature, salinity, and chlorophyll obtained from marine.copernicus.eu which processed in the 5-80 m depth range. The results showed that Humbold Bay had the highest average surface temperature distribution was 30 °C, with the highest average salinity from 35.89 ppt and the highest average chlorophyll value from 0.3859 mg/m3. The horizontal distribution of plankton had an average SV value of -76.63 dB, while the fish was -56.00 dB that evenly distributed. Vertically, the Sv of plankton decreased with increasing depth as well as the Sv of fish which its’ also did not have a distribution pattern in certain environmental parameters.

Cells of matter and life – towards understanding the internal structure and spatial patchiness of particles and plankton distribution in the Arctic fjords

Nothing is homogenous, neither the oceans, nor the distribution pattern of particles and plankton, both in the water column and within their patches. Here we analyse and map the spatio-temporal distribution patterns and the internal structure of 94 patches of various size fractions of particles and plankton studied in two Arctic fjords over six summer seasons. Observed patches generally occupied only the minor part of the studied upper water column (on average 12 %), and frequently occurred as multi-fraction forms. They varied among years and regions in terms of their position in a water column, size, shape, and structure. Consequently, we propose completely novel insight into their internal structure, by classifying them according to their shapes and the location of their cores. We distinguished seven types of patches: Belt, Triangle, Diamond, Flare, Fingers, Flag, and Rosette. The observed increasing role of the smallest size fractions (steepening size spectra slopes) over years implies that Atlantic water advection played the crucial role on compositional dynamics on temporal scale. The recurring feature of the elevated concentrations of particles and plankton near glacier fronts suggest that it, together with local biological production, is the strongest mechanism generating patchiness on the local scale. Even though we significantly extended our comprehension of the phenomenon of patchiness, it still remains an ambiguous matter, when, why, and if the mechanistic or ecological forcing prevails in shaping the patterns of particles and plankton distribution. Regardless of the mechanism, our results show that particles and plankton are not purely dye-like passive objects and that the type of their structuring in a water column may have only short term and local validity.

Short-Term Spatiotemporal Variability in Picoplankton Induced by a Submesoscale Front South of Gran Canaria (Canary Islands)

The distribution and variability of phytoplankton in the upper layers of the ocean are highly correlated with physical processes at different time and spatial scales. Model simulations have shown that submesoscale features play a pivotal role on plankton distribution, metabolism and carbon fluxes. However, there is a lack of observational studies that provide evidence for the complexity of short-term phytoplankton distribution and variability inferred from theoretical and modeling approaches. In the present study, the development and decay of a submesoscale front south of Gran Canaria Island is tracked at scales not considered in regular oceanographic samplings in order to analyze the picoplankton response to short-term variability. Likewise, the contribution of each scale of variability to the total variance of the picophytoplankton community has been quantified. We observe statistically different picophytoplankton assemblages across stations closer than 5 km, and between time periods shorter than 24 h, which were related to high physical spatiotemporal variability. Our results suggest that both temporal and spatial variability may equally contribute to the total variance of picoplankton community in the mixed layer, while time is the principal contributor to total variance in the deep chlorophyll maximum (DCM).

Monsoonal plankton distribution and physico-chemical water qualities in a rain-fed lake in Noakhali, Bangladesh

The study focused on the monsoonal distribution of plankton in a rain fed partial lake inSonapur, Noakhali district, Bangladesh. Three sampling sites were chosen between Sonapur zero point andNoakhali Science and Technology University. Four groups of phytoplankton such as Chlorophyceae (11genera), Bacillariophyceae (6 genera), Cyanophyceae (6 genera) and Euglenophyceae (3 genera) andfour groups of zooplankton such as Rotifera (10 genera), Cladocera (3 genera), Copepode (2 genera) andCrustacea (2 genera) were identified. The lake was found to be organic polluted (Palmer’s algal pollutionindex value: 22.33). The average wet land zooplankton index (WZI) value of this lake was estimated 3.72means moderate water quality. During the sampling periods some important physico-chemical parameterslike temperature (29-30 ?C), pH (7.8-8.2), transparency (6.5-13.50 cm), free CO2 (8.00-12.00 mg/l), totalalkalinity (13.00-14.50 mg/l), ammonia (0.1-0.5 mg/l), nitrate (0.05-0.25 mg/l), nitrite (0.03-0.07),phosphate (0.1-0.9 mg/l), dissolved oxygen (2-3.5 mg/l) and total suspended solids (4.0×10-4-5.3×10-4mg/l) were also determined as supporting water quality statement.

PLANKTON DISTRIBUTION IN CONTROLLED WATER OF MILKFISH LARVA CULTURE SYSTEM

The selection of planktons as live feed for milkfish larvae is a vital tool to meet the natural character as herbivorous species and to fulfill the needs for nutritious food for fish larval growth and survival. Phytoplankton Nannochloropsis sp. and zooplankton rotifer (Brachionus sp.) were two-selected plankton used as the main food source for the milkfish larvae. We performed this study in two times larval culture batch with four observations of tanks as replication. The results showed that we nourished both targeted planktons as larval food, regarding the positive impacts on larval growth (12±1,37 mm of total length, 7±4.89 mg of body weight) and a high survival rate (65.93–77.70%) achieved at the end of the culture period. Plankton diversity analysis presented that Class of rotifer (Monogononta) and Nannochloropsis sp. (Eustigmatophyceae) were both counted as the most dominant plankton group found in the rearing media, showing a decent sign of food supply for fish in rearing water column. The total number of planktons was high and had the tendency to follow the concentration of selected planktons over the culture period in the controlled water.