Macrozoobentos on the shelf of the Kronotsky Gulf

Data about the taxonomic composition and spatial distribution of bottom invertebrates of Kronotsky Gulf were obtained on results of bottom grab survey carried in September 2002. Analysis of the samples revealed 72 species of Polychaeta, 21 species of molluscs (Bivalvia), 17 species of crustaceans (mostly Amphipoda), 2 species of echinodermata (Echinoidea and Ophiuroidea). The average biomass in the depth range 25–200 m was 242±116 g/m2 where average density was 306±51 organisms/m2. The most high values of biomass were observed in the outlet parts of the rivers Zhupanova, Semyachik, Kronotskaya, where contribution of sea dollar Echinarachnius parma communities was principal. Despite fluctuations of the biomass of particular taxons during 50 years, the total biomass keeps stable (206–242 g/m2). Like in 1949 E. parma plays the main role in most bottom communities.

PEMETAAN BIOMASSA TEGAKAN HUTAN HUJAN TROPIS DI BUKIT MANDIANGIN MENGGUNAKAN CITRA SENTINEL-2 MSI

The preservation of standing biomass is one of the most vital elements for environmental sustainability and the sustainability of the forest itself. One of the actions that can be taken in an effort to maintain the sustainability of forest stand biomass is to map the distribution of biomass, and monitor changes or dynamics of stand biomass from time to time in a sustainable manner. This study aims to build a model based on remote sensing imagery to estimate the total biomass of tropical rainforest stands in Mandiangin Hill, South Kalimantan. The models developed in this study are based on vegetation indices extracted from Sentinel-2 MSI Imagery. A total of ten vegetation indices were tested in this study. For the construction process and validation of stand biomass estimation models, biomass information was measured directly in the field using a number of measuring plots. Stand biomass estimation models were made by correlating stand biomass information from the field with vegetation indices from Sentinel-2 MSI Imagery. The results showed that the most accurate model for estimating the biomass of tropical rainforest stands was 9.5806.exp (0.1454.PSSRa). Where PSSRa is Pigment Specific Simple Ratio. This model has a correlation coefficient (R2) of 0.876, a Mean Absolute Percentage Error (MAPE) of 16.8%, and a Root Mean Square Error (RMSE) of 32.6. The estimation results show that the total biomass of the Bukit Mandiangin tropical rainforest stands is between 11.7 to 998.5 Mg/ha, with an average biomass of 135.8 Mg/ha. Furthermore, the estimation of stand biomass in this study is limited to woody vegetation with a DBH of 10 cm and above. The PSSRa model with various improvements can be used to accurately estimate stand biomass

Plant Organic Matter in Palsa and Khasyrei Type Mires: Direct Observations in West Siberian Sub-Arctic

This article presents the first results of long-term direct measurements of a few major components of carbon cycle in permafrost mire landforms in the sub-Arctic region of Western Siberia, Russia. It reveals the main features of geographical distribution of plant organic matter, including both the above-ground and below-ground fractions of live biomass, the biomass of dead roots (mortmass), and net primary production (NPP) in peat-accumulating flat palsa mires and in “khasyrei”—ecosystems of drained lakes in thermokarst depression on epigenetic permafrost. The study based on original methods of direct field measurements elaborated by authors for northern peatlands. In northern taiga, the NPP of palsa mires was found in the range of 300–580 g m−2 yr−1 and an average biomass of 1800 g m−2; in khasyrei, it accounts for 1100 g m−2 yr−1 and 2000 g m−2 of NPP and live biomass, respectively. In forest tundra, the live biomass of palsa mires was found in the range of 1000–1800 g m−2, and in khasyrei it was 2300 g m−2. The NPP of palsa mires were in the range of 400–560 g m−2 yr−1, and in khasyrei it was 800 g m−2 yr−1. Overall, we conclude that the south–north climatic gradient in Western Siberia is the main driver of plant organic matter accumulation. It was found different across mire ecosystems of the same types but located in different bioclimatic regions.

Cultivation of young-of-the-year carp with the use of chlorella (Chlorella (Beijerinck, 1890)) suspension

Purpose. Investigate ecological conditions and determine fish productivity of ponds when growing young-of-the-year carp using a suspension of chlorella. Methodology. During the study, we used methods generally accepted in hydrochemistry, hydrobiology and fish farming. Findings. The article presents the results of the study on the use of chlorella suspension in the cultivation of carp. It was found that the use of chlorella suspension created favorable hydrochemical conditions resulting in intensive development of zooplankton, which had a positive effect on the growth of young-of-the-year carp and fish productivity of the pond. The development of the natural food supply was sufficient to meet the nutritional needs of juvenile carp. The average seasonal biomass of zooplankton in the experimental pond was 28.68 g/m3 that was 1.5 times higher than in the control. The share of cladocerans in the total biomass of zooplankton in the experimental pond was 76.6%, versus 36.8% in the control. The average biomass of zoobenthos for the growing season in the experimental was 1.3 times higher than in the control, and was formed by chironomid larvae, which are valuable in the food chain. Originality. The study investigated ecological conditions and fish productivity of growing ponds under conditions of the application of cattle manure and suspension of chlorella when growing carp in monoculture. Practical value. It was found that the use of chlorella suspension promotes the intensification of the development of zooplankton organisms in ponds. The obtained data can be used to develop practical recommendations for optimizing the conditions for growing carp seeds and increasing the biological productivity of ponds. Key words: nursery ponds, natural food supply, phytoplankton, zooplankton, zoobenthos, young-of-the-year carp, chlorella suspension, fish productivity.

Evaluation of the efficiency of a low-cost aerator and water quality in intensive production systems of tilapia with bioflakes at different stocking densities

Among the types of production systems applied in aquaculture, the biofloc culture system (BTF) has been gaining space due to its sustainable techniques. Noteworthy is the low or zero renewal of water, the formation of the microorganism population predominantly autotrophic and heterotrophic, resulting in microbial flakes. Taking into consideration the effectiveness of the system in tilapia farming, this work aimed at the fabrication, implementation, and analysis of the efficiency of a low-cost aerator. To evaluate and control the physical and chemical parameters of the water, 3,780 Nile tilapia fry were used with an initial average biomass of 3±0.5g, distributed in 24 rectangular tanks with a useful volume of 125 liters. The experiment included 6 treatments (T1: 360 fish m-3, T2: 1800 fish m-3, T3: 1080 fish m-3, T4: 1440 fish m-3, T5: 720 fish m-3 and T6: 2160 fish m-3) and four repetitions. The efficiency of the Venturi effect aerator and the water quality parameters were analyzed. Comparisons of the averages were performed using Tukey's test at 5% significance. From the dissolved oxygen analysis, it was possible to conclude that the aerator Venturi effect was efficient during the experiment, meeting the desired levels, also taking into consideration the ease of applicability and low cost for its development. Through the analysis of the physical-chemical parameters of the water and the mortality rates during the experiment, it can also be concluded that the safest density to operate using the bioflocci is up to 720 fish m-3.

Analysis of tree biomass, net sequestered carbon and bioenergy potency in dry forest ecosystem, Indonesia

This study examines the potential to tree component biomass, biomass for bioenergy product and sequester carbon of forest area. CO2FIX program was used to determine about these value. In order to know about these values, we used CO2FIX program. Thinning harvesting scenarios were analysed, involving the establishment of short rotation harvesting (each 10 years) and long rotation plantations (200 year). As a result, an overall tree biomass components (stem, foliage, branch and root) were respectively recorded as follow: 2.49 ton/ha±0.67, 0.14 ton/ha±0.03, 0.35 ton/ha±0.09 and 0.65 ton/ha±0.18. The potential of biomass for bioenergy product and sequester carbon was increase until the end of project simulation. The increase average biomass of bioenergy was 25.96 Mg/ha±13.46 and the average of net sequestered carbon increase about 16.6±35.9 MgCO2equiv/ha. Our analysis on this study for all research variables is highest at each 40 years period because at this age, the rate of increment in the biomass of the tree is maximized.

Effects of Ecological Restoration Using Non-Native Mangrove Kandelia obovata to Replace Invasive Spartina alterniflora on Intertidal Macrobenthos Community in Maoyan Island (Zhejiang, China)

Spartina alterniflora has extensively invaded the coastline of China, including in Maoyan Island of Zhejiang Province. Ecological restoration has been conducted using non-native mangrove Kandelia obovata to replace S. alterniflora in an attempt to restore the impacted intertidal zones. To illustrate the ecological effectiveness of the restoration projects, macrobenthos communities were studied among different habitats within the restored areas, including one non-restored S. alterniflora marsh (SA) and three differently-aged restored K. obovata stands planted in 2003, 2009, and 2011 respectively (KF14, KF8, and KF6). Besides, one unvegetated mudflat (MF) adjacent to the non-restored S. alterniflora marsh and one K. obovata forest transplanted in 2006 (RKF) at a previously barren mudflat without invasion history of S. alterniflora were set as reference sites. A total of 69 species of macrobenthos were collected from Maoyan Island, and the species richness was dominated by gastropoda (23 species), polychaeta (18 species), and malacostraca (16 species). There was no significant difference between the six sites in terms of the abundance of macrobenthos, with the average values of abundance peaking in KF6 (734.7 ind m−2) and being lowest in RKF (341.3 ind m−2). The six sites had significant differences in terms of the biomass of macrobenthos. The KF8 site contained the highest average biomass (168.3 g m−2), whereas the MF site had the lowest (54.3 g m−2). The Shannon-Wiener diversity index and Pielou’s evenness index of the macrobenthos did not exhibit significant differences among the six sites. However, the results of permutational multivariate analysis of variance (PERMANOVA) revealed significant spatial differences in the macrobenthos community structure between the sites. Since KF14 shared a similar macrobenthos community structure with RKF, while representing a strikingly different structure from SA, we infer that ecological restoration using K. obovata can restore the macrobenthos community to resemble to a normally planted K. obovata forest about 15 years after restoration.

High Performance of Biohydrogen Production in Packed-Filter Bioreactor via Optimizing Packed-Filter Position

In this present investigation, a packed-filter bioreactor was employed to produce hydrogen utilizing an expired soft drink as a substrate. The effects of feeding substrate concentrations ranging from 19.51, 10.19, 5.34, 3.48, to 2.51 g total sugar/L were examined, and the position of the packed filter installed in the bioreactor at dimensionless heights (h/H) of 1/4, 2/4, 3/4, and 4/4 was studied. The results revealed that with a substrate concentration of 20 g total sugar/L and a hydraulic retention time (HRT) of 1 h, a packed filter placed at the half-height position of the bioreactor (h/H 2/4) has the optimal hydrogen production rate, hydrogen yield, and average biomass concentration in the bioreactor, resulting in 55.70 ± 2.42 L/L/d, 0.90 ± 0.06 mol H2/mol hexose, and 17.86 ± 1.09 g VSS/L. When feeding substrate concentrations varied from 20, 10, to 5 g total sugar/L with the packed-filter position at h/H 2/4, Clostridium sp., Clostridium tyrobutyricum, and Bifidobacterium crudilactis were the predominant bacteria community. Finally, it was discovered that the packed-filter bioreactor can produce stable hydrogen in high-strength organic effluent.

PHYTOPLANKTON AS COMPONENT OF FODDER BASE IN MUNOZERO (LAKE ONEGA BASIN)

The paper presents the results of a study of phytoplankton in Lake Munozero during the vegetation period in 2018. The seasonal dynamics of the biomass and abundance of algae in the southern and northwestern reaches experiencing different anthropogenic pressures has been considered. The reservoir stands out among other water bodies of the Republic of Karelia for its chemical and morphometric characteristics. It is characterized by high mineralization (up to 100 mg/l), isolation of the reaches, low color and content of nutrients and organic compounds. There have been identified 147 taxa of the algoflora with a rank lower than the genus, belonging to 9 divisions. The structure of algocenoses in terms of species richness and quantitative development is determined by representatives of centric diatoms, cyanobacter, dinophytes, and chlorococcal greens, which is important for the formation of the fish food base. Average size of phytoplankton during 2018 in the northwestern reach reached 492 thousand cells/l, the average biomass was 0.468 g/m3. The average size of phytoplankton in the southern reach reached 589 thousand kg/l, the average biomass was 0.459 g/m3. The water quality in the northwestern and southern reaches by the value of the saprobic index corresponds to the III class of waters, but the biomass values characterize both parts of the reservoir as oligotrophic. Shannon's index, quantitative and structural characteristics of phytoplankton differ in the northwestern and southern reaches, seasonal dynamics is not typical for phytoplankton of the oligotrophic Karelian lake. According to the data on abundance and biomass of phytoplankton of Lake Munozero the value of commercial fish catch was calculated.

Shell-bearing mollusks of the order Cephalaspidea (Gastropoda: Heterobranchia) of the Kara Sea: fauna and ecology

The survey of shell-bearing heterobranchs of the order Cephalaspidea of the Kara Sea has been done based on unpublished and literature data. The studied material includes that collected during expeditions aboard R/V Professor Multanovskiy in August–September 2019 and R/V Dalnie Zelentsy in August 2012. Additionally, the material of collections of the Zoological Institute of the Russian Academy of Sciences (Saint Petersburg) has been studied. The fauna of heterobranch molluscs of the order Cephalaspidea in the Kara Sea includes 18 described and 1 undescribed species that belong to 10 genera and 6 families. It has been specified that the type locality of Retusa semen Reeve, 1855 (Port Refuge) is located at Port Refuge National Historic Site of Canada, Devon Island, Nunavut, not in the Kara Sea. Retusa semen is considered here as species inquirenda because of the brief original description, significant differences in drawings of the shell of this species made by different authors, and the absence of type specimens. The presence of Diaphana minuta Brown, 1827, Laona quadrata (Wood, 1839), Philine sinuata Stimpson, 1851 and Retusa semen in the Kara Sea needs confirmation. Species numbers of heterobranch molluscs of the order Cephalaspidea decrease from the Barents Sea (21) through the Kara Sea (19) to the Laptev Sea (15) because of the decreasing proportion of boreal-arctic species. Among cephalaspids of the Kara Sea, the highest average abundance (individuals/m2) was observed for Cylichnoides densistriatus (Leche, 1878), and the highest average biomass for Cylichna corticata (Møller, 1842). The proportion of live individuals in the populations does not exceed 18% in late August – early September. The taxonomic structure of the cephalaspid fauna of the Kara Sea has been studied based exclusively on morphological characters. Further study of the fauna is needed based on molecular analyses of the material fixed in 96˚ alcohol.