Differential Effects of the Allelochemical Juglone on Growth of Harmful and Non-Target Freshwater Algae

Allelopathy has been applied to control nuisance algae in aquatic systems, but the effects of allelochemicals on the broad spectrum of algae are not well understood. We investigate algicidal effects of the allelochemical juglone on the bloom-forming, harmful algae Microcystis aeruginosa and Stephanodiscus hantzschii, and on several non-target algal species including cyanobacteria (Anabaena flos–aquae, Oscillatoria curviceps, and Phormidium subfuscum), diatoms (Asterionella formosa, Fragilaria crotonensis, and Synedra acus), and green algae (Chlorella vulgaris, Scenedesmus ecornis, and Scenedesmus quadricauda), in laboratory and field enclosure bioassays. Under three treatment concentrations (0.01, 0.1, and 1 mg L−1) of juglone, Microcystis cell density is significantly reduced by 35–93%. Concentrations of 0.1 and 1 mg L−1 inhibits Stephanodiscus growth almost equally (66% and 75%, respectively). To contrast, juglone produces a stimulatory allelopathic effect on three green algae, and other tested diatoms showed hormesis. Overall, the cyanobacteria are more sensitive to juglone than the green algae and diatoms. These results indicate that the allelopathic effects of juglone on microalgae vary depending on their characteristic cellular morphology and anatomy.

Short Communication: Community of phytoplankton in peatland canal, Riau, and wet dune slacks of Parangtritis, Yogyakarta, Indonesia

Mawarni A, Azizah FNN, Sartika HW, Hadisusanto S, Putri DM, Reza A. 2020. Short Communication: Community of Phytoplankton in peatland canal, Riau, and wet dune slacks of Parangtritis, Yogyakarta, Indonesia. Biodiversitas 21: 1874-1879. The ecosystems of peatland canal and wet dune slacks have specific characteristics for phytoplankton community. This study aimed to elaborate on the distribution and abundance of phytoplankton community in peatland canal of Sungai Tohor Village, Meranti Islands, Riau and wet dune slacks of Parangtritis, Special Region of Yogyakarta. Phytoplankton was collected using a 2-L modified Van Dorn water sampler. In peatland, canal phytoplankton was sampled at 3 different locations, each with 5 repetitions. Meanwhile, in wet dune slacks, phytoplankton was sampled at 5 locations, each with 3 repetitions. Phytoplankton samples were filtered with Wisconsin plankton-net 120 mesh and fixed with 3 drops of formaldehyde 4%. The measured physical and chemical factors were air temperature, water temperature, dissolved oxygen, alkalinity, carbon dioxide, pH, depth, transparency, nitrate, sulfate, and phosphate concentration. The results showed that the distribution and abundance of phytoplankton community in wet dune slacks were greater than those of the peatland community. This research found 18 species of phytoplankton in peatland canal, dominated by Synedra acus and 116 species of phytoplankton in wet dune slacks, dominated by Cyclotella meneghiniana.

Toxic effect of poly(hexamethylene guanidine) on diatom algae

Poly(hexamethylene guanidine) has been used for several decades as a disinfectant for various surfaces and water, including drinking water. Its use has increased significantly due to the COVID-19 pandemic. The toxicity of poly(hexamethylene guanidine) has been studied on warmblooded animals and fish, but there is little data on its action on planktonic organisms. For the first time the effect of poly(hexamethylene guanidine) (Anavidin preparation) on diatom algae which are one of the main producers of oxygen and photosynthesized organic substances was studied. The obtained data indicate complete suppression of the growth of the diatom Ulnaria ferefusiformis (formerly known as Synedra acus) at a concentration of 0.5 mg/L. Diatom growth is suppressed by more than 30% at 0.1 mg/L Anavidin, which corresponds to the MAC for water bodies for household and domestic use. Addition of polymeric acids, for example, poly(acrylic acid) partially neutralizes the toxic effect of poly(hexamethylene guanidine). Thus, due to the widespread use of poly(hexamethylene guanidine), it is necessary to thoroughly study its effect on various inhabitants of aquatic ecosystems.

Automatic accounting of Baikal diatomic algae: approaches and prospects

Using the TensorFlow Object Detection API, an approach to identifying and registering Baikal diatom species Synedra acus subsp. radians has been tested. As a result, a set of images was formed and training was conducted. It is shown that аfter 15000 training iterations, the total value of the loss function was obtained equal to 0,04. At the same time, the classification accuracy is equal to 95%, and the accuracy of construction of the bounding box is also equal to 95%.

Bacteria associated with planktonic diatoms from Lake Baikal

Algal-bacterial associations were studied in unialgal xenic cultures of Synedra acus subsp. radians, Asterionella formosa and Fragillaria crotonensis planktonic diatoms from Lake Baikal, using epifluorescent and scanning electron microscopy. It was found that rod- and ovoid-shaped bacteria colonized cell walls of diatoms. Cloning and sequencing of fragments of 16S rRNA gene in diatom cultures revealed members of Gammaproteobacteria (Pseudomonas sp.), Betaproteobacteria (Janthinobacterium sp., Hydrogenophaga sp., Methylophilus sp.), Bacteroidetes (Flavobacterium sp., Pedobacter sp.), and Acinobacteria (Nocardioides sp.).

Mikroalga Divisi Bacillariophyta yang Ditemukan di Danau Aur Kabupaten Musi Rawas

Lake Aur has many aquatic biota as well as become one of the mainstay attractions in Musi Rawas Regency. Community activities and lack of awareness of tourists on the cleanliness and importance of maintaining the lake environment have an impact on water pollution. One of the organisms that can be used as an indicator of river water quality is microalgae. The purpose of this study is to determine the types of microalgae Bacillariophyta divisions that exist in the lake Aur, Musi Rawas.The type of research used is survey research. Bacillariophyta Division consists of two classes, 6 orders, 7 families, 8 genera and 11 species. Observed environmental factors: temperature: 290C, pH: 6.7, Brightness: 115 cm and dissolved oxygen amount of: 38 mg / L. Based on the results of research and discussion, we can conclude that: the type of microalgae division bacillariophyta were found in Lake Aur namely: Cylotella sp, Eunotia sp, Eunotia pectinalis, Fragilaria croronensis, Synedra acus, Nitzschia sp, Nitzschia acicularis, Surirella sp, Surirella elegans, Pinnularia sp and Stauroneis sp.

PENGARUH INTENSITAS MUSIM HUJAN TERHADAP KELIMPAHAN FITOPLANKTON DI WADUK BENING SARADAN

This study aims to determine the effect of the intensity of the rainy season to the abundance of phytoplankton in the reservoir Bening Madison County. As well as exploit some results of research on the abundance of phytoplankton as a medium of learning materials were shaped poster on the types of phytoplankton. This study uses a quantitative approach to the exploration technique. There are six points each station with two sample replicates. The results showed that in Reservoir Bening Saradan found 16 species of phytoplankton that is Synedra acus, Synedra ulna, Navicula grevillei, Tetragonodium verum, Crucigenia rectangularis, Ulothrix cylindricum, Nitzchia paleaceae, Ceratium candelabrum, Goniochloris sculpta, Scenedesmus ocuminatus, Navicula sp, Nitzchia acicularis, Spirulina major, Ceratoneis acus, Pediastrum simplex, Pleurota eniumtrabecula. Phytoplankton abundance is the most ubiquitous class Bacillariophyceae. Phytoplankton abundance is influenced by monsoon intensity 40,9%. While 59,1% of other factors influenced the agricultural wastes that contain elements of N, P, K, which can improve nutrient. The highest phytoplankton abundance in December is 138,64 ind/l with 12 species of phytoplankton. The number of rainy days in the December low at 25/31 days allows a maximum of phytoplankton photosynthesis. Lowest phytoplankton abundance in February which is 65,14 ind/l. Phytoplankton abundance is directly proportional to the intensity of the rainy season. The number of higher intensity, phytoplankton abundance is also higher, and vice versa. Physical and chemical conditions Bening Reservoir categorized according to the results of research in the waters of the state are less fertile and less than optimal for the growth ofphytoplankton.