The distribution and population dynamics of Ostracoda and their response to environmental factors... more The distribution and population dynamics of Ostracoda and their response to environmental factors have been analyzed in Crimean hypersaline lakes based on data from a long-term monitoring study (2005-2016). Only one representative of this class, Eucypris mareotica (Fischer, 1855), occurs in these lakes. The species was recorded in the Crimean lakes at a maximum salinity of 300 g/L. The frequency of occurrence of this species correlated negatively with salinity. This species reached high abundances in plankton (650000 ind./m 3), benthos (565000 ind./m 2), and floating mats of filamentous green algae Cladophora spp. (9900000 ind./kg of wet weight of the mat). Ostracods were shown to reduce the concentration of calcium and magnesium in the water as a result of using these elements for the construction of their shells. The possibility of using the shells of ostracods for paleoclimatic and palaeolimnological reconstructions was discussed .
На основании многолетних наблюдений (2005–2016 гг.) проанализированы распространение, ди-
намика ... more На основании многолетних наблюдений (2005–2016 гг.) проанализированы распространение, ди- намика численности и влияние разных факторов среды на Ostracoda в гиперсоленых озерах Крыма. Показано, что в водоемах встречается только один представитель класса – Eucypris mareotica (Fischer, 1855). Вид отмечен в озерах Крыма при максимальной солености 300 г/л. Частота встречаемости вида имеет обратную связь с соленостью. Рачки достигают высокой численности в планктоне (650 тыс. экз./м3), бентосе (565 тыс. экз./м2) и плавучих матах нитчатых зеленых водорослей Cladophora spp. (9.9 млн экз./на 1 кг сырой массы мата). Используя кальций и магний для построения сво- их раковин, остракоды снижают концентрацию этих элементов в воде. Отмечена возможность ис- пользования раковин остракод для палеоклиматических и палеолимнологических реконструкций.
Изучено влияние дозы гамма-облучения 2.5, 5.5 и 7.5 Гр, полученной цистами Artemia,
на выход науп... more Изучено влияние дозы гамма-облучения 2.5, 5.5 и 7.5 Гр, полученной цистами Artemia, на выход науплиусов и постнауплиальную выживаемость рачков при 0, 9, 18, 36, 54, 62, 78 и 88 г/л. При этих же солёностях оценивали вышеуказанные параметры в условиях без об- лучения. Установлено, что скорость вылупления науплиусов из цист в первую очередь за- висит от солёности, коэффициент детерминации равен 90%. Доза облучения не влияет на выход науплиусов при всех солёностях, кроме 54 г/л, когда была найдена достоверная нега- тивная связь между долей вылупившихся науплиусов и дозой облучения. Выживаемость рачков из облученных цист зависела от солёности. В диапазоне солёности 9 – 52 г/л она бы- ла достоверно меньше, чем в диапазоне 62 – 88 г/л (дозы 2.5 и 5.5 Гр). Рачки, вышедшие из цист, получивших дозу 7.5 Гр, не доживали до 12 дня при солёности 88 г/л. Минимальная выживаемость рачков отмечена при солёности 54 г/л при всех дозах облучения, данная со- лёность может считаться для артемий критической, при ней происходит перенастройка ме- ханизма осморегуляции. Экологические эффекты в популяциях артемий могут проявляться, начиная с доз облучения 2.5 Гр. Изученные дозы облучения могут иметь и отдаленные по- следствия для популяции артемий в гиперсолёных водоёмах. Для корректной количественной оценки эффекта этих доз на популяции артемий необходимы исследования не только генера- ции рачков, которая вылупилась из облученных цист, но и 2–3 последующих поколений.
Sivash Bay is the largest hypersaline lagoon in the world. In 1963-1975 the North Crimean Canal w... more Sivash Bay is the largest hypersaline lagoon in the world. In 1963-1975 the North Crimean Canal was constructed, with water from the River Dnieper and discharge of drainage water collected from agricultural lands into Sivash Bay. Salinity in Sivash Bay began to drop, resulting in a new brackish water ecosystem. The political decision to stop supplying water from the River Dnieper to the Canal was made in 2014, and the discharge of fresh water into the lagoon ended, resulting in an increase in salinity up to 60-75 g l −1. This study showed that the abundance of meiobenthos increased, with Nematoda dominating. The composition of nematode species in the lagoon has not previously been studied. Using samples from 1979, 2013 and 2015, 50 nematode species and forms were identified in 1979, 32 in 2013 and 21 in 2015. The species composition of nematodes at different periods was significantly different. The average abundance of nematodes was 134 198 ind. m −2 in 2013 and 606 660 ind. m −2 in 2015.
Artemia spp. play a key role in hypersaline ecosystems. Artemia can live in a salinity range from... more Artemia spp. play a key role in hypersaline ecosystems. Artemia can live in a salinity range from 10 to 300-340 g/L, but in water bodies where salinity is between 10 and 100 g/L, it may be absent. Is the absence of Artemia in some Crimean lakes determined by the presence of predators or by salinity? To answer this question field long-term and experimental data collected in the Crimean lakes were used. With the least probability, the populations of Artemia existed in the lakes with a salinity of up to 50 g/L or above 300 g/L. Self-reproducing Artemia populations (all age stages) were most likely (≥80% of occurrence) noted in the salinity range of 150-200 g/L. Long-term monitoring in two lakes showed that in different years, a significant negative correlation of Artemia abundance with the numbers of amphipod Gammarus aequicauda and ostracod Eucypris mareotica was found in both lakes. This correlation can be explained by ostracod and amphipod predation on Artemia. In years without predator populations, the number of Artemia was higher by several times. Experiments showed that these amphipods and ostracods consume brine shrimps of different developmental stages. There are at least 12 crustacean species, 5 insect species, and 2 fish species, all listed in this paper, which inhabit Crimean hypersaline waters and can eat Artemia. Their predation on Artemia often is a main cause of its absence in the salinity range from 10 to 150 g/L.
Artemia spp. play a key role in hypersaline ecosystems. Artemia can live in a salinity range from... more Artemia spp. play a key role in hypersaline ecosystems. Artemia can live in a salinity range from 10 to 300-340 g/L, but in water bodies where salinity is between 10 and 100 g/L, it may be absent. Is the absence of Artemia in some Crimean lakes determined by the presence of predators or by salinity? To answer this question field long-term and experimental data collected in the Crimean lakes were used. With the least probability, the populations of Artemia existed in the lakes with a salinity of up to 50 g/L or above 300 g/L. Self-reproducing Artemia populations (all age stages) were most likely (≥80% of occurrence) noted in the salinity range of 150-200 g/L. Long-term monitoring in two lakes showed that in different years, a significant negative correlation of Artemia abundance with the numbers of amphipod Gammarus aequicauda and ostracod Eucypris mareotica was found in both lakes. This correlation can be explained by ostracod and amphipod predation on Artemia. In years without predator populations, the number of Artemia was higher by several times. Experiments showed that these amphipods and ostracods consume brine shrimps of different developmental stages. There are at least 12 crustacean species, 5 insect species, and 2 fish species, all listed in this paper, which inhabit Crimean hypersaline waters and can eat Artemia. Their predation on Artemia often is a main cause of its absence in the salinity range from 10 to 150 g/L.
Изучено влияние дозы гамма-облучения 2.5, 5.5 и 7.5 Гр, полученной цистами Artemia, на выход науп... more Изучено влияние дозы гамма-облучения 2.5, 5.5 и 7.5 Гр, полученной цистами Artemia, на выход науплиусов и постнауплиальную выживаемость рачков при 0, 9, 18, 36, 54, 62, 78 и 88 г/л. При этих же солёностях оценивали вышеуказанные параметры в условиях без облучения. Установлено, что скорость вылупления науплиусов из цист в первую очередь зависит от солёности, коэффициент детерминации равен 90%. Доза облучения не влияет на выход науплиусов при всех солёностях, кроме 54 г/л, когда была найдена достоверная негативная связь между долей вылупившихся науплиусов и дозой облучения. Выживаемость рачков из облученных цист зависела от солёности. В диапазоне солёности 9 – 52 г/л она была достоверно меньше, чем в диапазоне 62 – 88 г/л (дозы 2.5 и 5.5 Гр). Рачки, вышедшие из цист, получивших дозу 7.5 Гр, не доживали до 12 дня при солёности 88 г/л. Минимальная выживаемость рачков отмечена при солёности 54 г/л при всех дозах облучения, данная солёность может считаться для артемий критической, при ней происходит перенастройка механизма осморегуляции. Экологические эффекты в популяциях артемий могут проявляться, начиная с доз облучения 2.5 Гр. Изученные дозы облучения могут иметь и отдаленные по- следствия для популяции артемий в гиперсолёных водоёмах. Для корректной количественной оценки эффекта этих доз на популяции артемий необходимы исследования не только генерации рачков, которая вылупилась из облученных цист, но и 2–3 последующих поколений.
Salinity is one of the most important factors in aquatic ecosystems, but its filtering role in th... more Salinity is one of the most important factors in aquatic ecosystems, but its filtering role in the Diptera community species composition is still poorly studied. This issue was studied in the diverse Crimean water bodies. A total of 425 samples were collected from freshwater to hypersaline waters. In 73% of the 425 samples examined, representatives of Diptera were found; their larvae and pupae belonged to seven families. Сhironomid species composition was analyzed in 47 samples. The most common were Chironomidae, which were in 94% of samples with Diptera, Ceratopoganidae were in 8% of samples, Ephydridae were in 5% of samples, Simuliidae were in 4% of samples, Culicidae and Chaoboridae were in 4% of samples, and Syrphidae was in only one sample. A total of 14 Chironomidae genera and 21 species and forms were found; 9 of them are new for Crimea. Reduction of the dominance variants in the community, as well as the number of chironomid species, with increasing salinity may indicate an increase in the filtering role of salinity in the Diptera community species composition that is still poorly studied.
Our sustainable environmental management must be based on adequate ecological concepts. The quest... more Our sustainable environmental management must be based on adequate ecological concepts. The question arises: what concept is better to use for understanding and management of ecosystems? To look for an answer, we concentrate our attention on saline lakes. Every ecosystem has several alternative stable states and may demonstrate regime shifts, which are large, abrupt, persistent changes in the structure and function of a system. To understand the dynamics of ecosystems the Concept of Multiplicity of Ecosystem Alternative Stable States as a new ecological paradigm has been developed recently. The author analyzes the emerging paradigm using the case of saline lakes, and discusses how to base our adaptive environmental management on the developing paradigm. Diff erent issues of development of the concept and its application to salinology as a scientifi c basis of an integrated management of a saline lake and its watershed are discussed. The concept may serve as one of the key theoretical elements of the scientifi c basis in sustainable environmental management.
Filamentous green algae play an important functional role in element cycling and productivity in ... more Filamentous green algae play an important functional role in element cycling and productivity in the diff erent water bodies. In hypersaline lakes and lagoons of the Crimea, fi lamentous green algae are present and form bottom and fl oating mats that occupy large areas with high biomass, up to 4-5 kg (wet biomass)/m 2. Cladophora spp. dominated in those mats. Five species of fi lamentous green algae (Chlorophyta) in Lake Chersonesskoye: Cladophora vadorum (Aresch.) Kütz., C. siwaschensis C. Meyer, C. echinus (Biasol.) Kütz., Ulothrix implexa (Kütz.) Kütz., Rhizoclonium tortuosum (Dillw.) Kütz., and seagrass (Angiospermae) Ruppia cirrhosa (Petagna) Grande were found. Cladophora spp. and R. cirrhosa were found in the lake throughout the year, other types of algae were encountered episodically. In most cases the biomass of bottom mat exceeded that of the fl oating mat. In general, the total biomass of the bottom and fl oating mats in the lake areas at depths up to 30 cm was in a stable range of values from 100 to 290 mg (dry weight)/cm 2. Animal and infusorian average abundance in mats reach high values: infusorians-up to 15 000 000 ind./m 2 , Cletocamptus retrogressus (Copepoda, Harpacticoida)-up to 730 000 ind./m 2 , Eucypris mareotica (Ostracoda)-up to 91 000 ind./m 2 and Chironomidae larvae (Insecta, Diptera)-up to 140 ind./m 2. Those values were much higher than in the plankton.
The statement that the world’s ecosystems are
rapidly deteriorating due to human intervention and... more The statement that the world’s ecosystems are rapidly deteriorating due to human intervention and global warming is nowadays commonplace. Some of the ecosystems most heavily impacted are inland salt lakes. The salt lakes are among the most valuable and fascinating ecosystems on Earth, and their study has both basic scientifi c interest as well as applied aspects.
On the Crimean peninsula, there are more than 50 hypersaline water bodies, including the Sivash (... more On the Crimean peninsula, there are more than 50 hypersaline water bodies, including the Sivash (the Sea of Azov), the largest hypersaline lagoon in the world. Based on the literature and our own long-term research data (2000-2017), a review of the fauna of the hypersaline waters in the Crimea is presented, including 298 species of animals belonging to 8 phyla, 14 classes and 27 orders. The variety of phyla and classes within a particular range of salinity was shown to decrease significantly with an increase in salinity; 8 classes in 3 phyla can withstand salinities above 100 g/L, and only 4 classes (Branchiopoda, Hexanauplia, Ostracoda and Insecta) within 1 phylum (Arthropoda) occur at salinities above 200 g/L. The number of species found in a single sample also decreased with increasing salinity. However, in the range of 50-120 g/L, the number of species was mainly determined by a different set of factors. The abundance of animals in the hypersaline waters of the Crimea can be very high: e.g., Nematoda-up to 1.4•10 7 ind./m 2 , Harpacticoida-up to 3.5•10 6 ind./m 2 , Ostracoda-up to 5.8•10 5 ind./m 2 , and Moina salina-up to 1.3•10 6 ind./m 3. A characteristic feature of hypersaline water ecosystems is the fact that increases in salinity cause increasing amounts of benthic animals (Chironomidae, Harpacticoida, Ostracoda) to change their habitats from the bottom to the water column. At salinities above 120-150 g/L, there is almost no animal life at the bottom. Most of the species found in shallow hypersaline waters have a resting stage in their life cycle, which ensures their survival in abruptly changing environments, even those in ephemeral water bodies.
Гиперсоленые водоемы, соленость которых превышает 35 г/л, широко распространены на планете (гипе... more Гиперсоленые водоемы, соленость которых превышает 35 г/л, широко распространены на планете (гиперсоленые озера и лагуны, глубоководные "озера", поровые воды морских льдов) и относятся к числу наиболее экстремальных местообитаний Земли. В работе обобщены и проанализированы результаты собственных многолетних исследований экосистем гиперсоленых озер и лагун Крыма и литературные данные. Эти экосистемы уникальны как по физико-химическим показателям, так и по структуре и функционированию населяющей их биоты. В гиперсоленых водоемах температур-ный диапазон, в котором вода остается жидкой и может существовать жизнь, шире, чем в пресных или морских. При солености 350 г/л этот диапазон-от-35°С до +109°С. Видовое разнообразие эу-кариотных организмов с ростом солености резко убывает, а прокариотных увеличивается. В прес-новодных и морских экосистемах поступление энергии в экосистемы в основном обеспечивает ок-сигенный фотосинтез. В гиперсоленых озерах энергия поступает от трех групп фототрофов и разно-образных хемотрофов. Например, аноксигенный фотосинтез может обеспечивать до 85% поступающей в экосистему энергии, и его доля в общей первичной продукции при увеличении со-лености выше 100-160 г/л растет. Многие гиперсоленые водоемы, несмотря на экстремальность среды, являются высокопродуктивными. Данный парадокс можно объяснить двумя причинами: 1) высокими концентрациями биогенов и 2) высокой мелкомасштабной пространственно-времен-ной изменчивостью абиотических факторов. Это позволяет взаимодействовать противоположно направленным процессам и замыкать циклы внутри одного сообщества. Одним из механизмов осмоадаптации первичных продуцентов к высокой солености и ее резким колебаниям является вы-деление ими в среду экзополисахаридов. Их количество увеличивается с ростом солености и может составлять до 50-70% первичной продукции, что ведет к возрастанию роли гетеротрофных осмот-рофов в пищевых сетях. Дальнейшее изучение гиперсоленых местообитаний может расширить на-ши представления об организации жизни в экстремальной среде.
Citation: Zadereev E.S., Shadrin N.V. In search for common ground: studies of freshwater and sali... more Citation: Zadereev E.S., Shadrin N.V. In search for common ground: studies of freshwater and saline lakes. J. Sib. Fed.
—The dynamics of food chains upon changes in water salinity has been analyzed using the example o... more —The dynamics of food chains upon changes in water salinity has been analyzed using the example of six poly-and hyperhaline lakes in the Crimea. The results show that ecosystems of saline lakes are sensitive to the impact of external factors. Changes in weather conditions often lead to fluctuations of water salinity, which may cause a changeover in the hydrobiological regime of the lake. In lakes with high water salinity, the shortening of food chain takes place, and the cascade effect is observed in their dynamics.
Shadrin N. V., Anufriieva E. V. An ecosystem role of spatial and temporal inhomogeneity in feedin... more Shadrin N. V., Anufriieva E. V. An ecosystem role of spatial and temporal inhomogeneity in feeding of planktonic crustaceans // Ekosystemy. 2018. Iss. 14 (44). P. 119–128. The aggregated distribution of planktonic crustaceans and the presence of diurnal feeding rhythms of them are well known phenomena. At the same time, the significance of spatial heterogeneity and temporal variability in the feeding of crustaceans in the stable functioning of the system «phytoplankton – zooplankton» can not be considered sufficiently understood. Using numerous data from field and experimental studies, on the basis of mental and numerical models, the authors analyzed the possible ecosystem role of the spatial and temporal heterogeneity of feeding of planktonic crustaceans. The presence of diurnal feeding rhythms maximizes the productivity of microalgae and crustaceans, stabilizing the «phytoplankton – zooplankton» system and reducing the probability of its extinction. The formation of crustacean aggregation in plakton is determined by their motor reactions of animals to the concentration of algae. With a certain algorithm of the behavior of the crustaceans aggregation, the spatial heterogeneity of their feeding also leads to the maximization of the production of microalgae and crustaceans, and the stabilization of the «phytoplankton – zooplankton» system.
In the Crimea, there are many hypersaline lakes and lagoons, where Eucypris mareotica (Ostracoda)... more In the Crimea, there are many hypersaline lakes and lagoons, where Eucypris mareotica (Ostracoda), high halotolerant species, inhabit. Despite the wide distribution of the species and the abundance of its populations, little is known about the biology of E. mareotica, including its nutrition. Diversity of microalgae in gut of E. mareotica in Lake Chersonesskoye was studied. The crustaceans ate both phytoplankton and alga, which growth on cladophora filaments, as well as various small animals, but microalgae played a main role in their nutrition. The proportion of individuals, which had algae in intestines, ranged in a sample from 0 to 93%. In 335 analyzed individuals, 22 species of microalgae were found, which belong to 4 types, 4 classes and 11 orders. Of these, 4 species belong to the type Cyanobacteria, 3 – to Myzozoa, 4 – to Haptophyta, 11 – to Ochrophyta. The most common species was Peridinium cinctum. Given the availability of a wide variety of consumed microalgae, ostracod gut content analysis can be used to assess species diversity of microalgae in the lakes.
Lagoon Bardawil, belonging to the few hypersaline lagoons in the Mediterranean Sea, is located in... more Lagoon Bardawil, belonging to the few hypersaline lagoons in the Mediterranean Sea, is located in the middle of the Sinai coast. Composition, distribution, and seasonal dynamics of large planktonic tintinnids and foraminifera at 12 stations in the lagoon were studied in 2009 and 2010. Fifteen species of Ciliophora (Tintinnina) and two species of Foraminifera were identified. The occurrence of different species varied greatly in the study period: two species were found in 42% to 49% of all samples, two species in 21% to 23%, 4 species in 10% to 20%, and 10 species in 1% to 5%. Only three species were found throughout the year. The average total number of all recorded protozoa varied from 2333 ind./m3 (spring) to 13,733 ind./m3 (winter): Tintinnina from 1250 ind./m3 (spring) to 12,867 ind./ m3 (winter) and Foraminifera from 200 ind./m3 (autumn) to 1083 ind./m3 (spring). The distribution of total abundance of tintinnids and foraminifers in the lagoon area was close to random in summer and spring; during autumn and winter, it was aggregated. Tintinnid and foraminifera studies in Lagoon Bardawil were carried out previously (1985–2010); summarizing all data, it was found that interannual differences may be explained by stochastic causes and nondirected climate fluctuations.
The distribution and population dynamics of Ostracoda and their response to environmental factors... more The distribution and population dynamics of Ostracoda and their response to environmental factors have been analyzed in Crimean hypersaline lakes based on data from a long-term monitoring study (2005-2016). Only one representative of this class, Eucypris mareotica (Fischer, 1855), occurs in these lakes. The species was recorded in the Crimean lakes at a maximum salinity of 300 g/L. The frequency of occurrence of this species correlated negatively with salinity. This species reached high abundances in plankton (650000 ind./m 3), benthos (565000 ind./m 2), and floating mats of filamentous green algae Cladophora spp. (9900000 ind./kg of wet weight of the mat). Ostracods were shown to reduce the concentration of calcium and magnesium in the water as a result of using these elements for the construction of their shells. The possibility of using the shells of ostracods for paleoclimatic and palaeolimnological reconstructions was discussed .
На основании многолетних наблюдений (2005–2016 гг.) проанализированы распространение, ди-
намика ... more На основании многолетних наблюдений (2005–2016 гг.) проанализированы распространение, ди- намика численности и влияние разных факторов среды на Ostracoda в гиперсоленых озерах Крыма. Показано, что в водоемах встречается только один представитель класса – Eucypris mareotica (Fischer, 1855). Вид отмечен в озерах Крыма при максимальной солености 300 г/л. Частота встречаемости вида имеет обратную связь с соленостью. Рачки достигают высокой численности в планктоне (650 тыс. экз./м3), бентосе (565 тыс. экз./м2) и плавучих матах нитчатых зеленых водорослей Cladophora spp. (9.9 млн экз./на 1 кг сырой массы мата). Используя кальций и магний для построения сво- их раковин, остракоды снижают концентрацию этих элементов в воде. Отмечена возможность ис- пользования раковин остракод для палеоклиматических и палеолимнологических реконструкций.
Изучено влияние дозы гамма-облучения 2.5, 5.5 и 7.5 Гр, полученной цистами Artemia,
на выход науп... more Изучено влияние дозы гамма-облучения 2.5, 5.5 и 7.5 Гр, полученной цистами Artemia, на выход науплиусов и постнауплиальную выживаемость рачков при 0, 9, 18, 36, 54, 62, 78 и 88 г/л. При этих же солёностях оценивали вышеуказанные параметры в условиях без об- лучения. Установлено, что скорость вылупления науплиусов из цист в первую очередь за- висит от солёности, коэффициент детерминации равен 90%. Доза облучения не влияет на выход науплиусов при всех солёностях, кроме 54 г/л, когда была найдена достоверная нега- тивная связь между долей вылупившихся науплиусов и дозой облучения. Выживаемость рачков из облученных цист зависела от солёности. В диапазоне солёности 9 – 52 г/л она бы- ла достоверно меньше, чем в диапазоне 62 – 88 г/л (дозы 2.5 и 5.5 Гр). Рачки, вышедшие из цист, получивших дозу 7.5 Гр, не доживали до 12 дня при солёности 88 г/л. Минимальная выживаемость рачков отмечена при солёности 54 г/л при всех дозах облучения, данная со- лёность может считаться для артемий критической, при ней происходит перенастройка ме- ханизма осморегуляции. Экологические эффекты в популяциях артемий могут проявляться, начиная с доз облучения 2.5 Гр. Изученные дозы облучения могут иметь и отдаленные по- следствия для популяции артемий в гиперсолёных водоёмах. Для корректной количественной оценки эффекта этих доз на популяции артемий необходимы исследования не только генера- ции рачков, которая вылупилась из облученных цист, но и 2–3 последующих поколений.
Sivash Bay is the largest hypersaline lagoon in the world. In 1963-1975 the North Crimean Canal w... more Sivash Bay is the largest hypersaline lagoon in the world. In 1963-1975 the North Crimean Canal was constructed, with water from the River Dnieper and discharge of drainage water collected from agricultural lands into Sivash Bay. Salinity in Sivash Bay began to drop, resulting in a new brackish water ecosystem. The political decision to stop supplying water from the River Dnieper to the Canal was made in 2014, and the discharge of fresh water into the lagoon ended, resulting in an increase in salinity up to 60-75 g l −1. This study showed that the abundance of meiobenthos increased, with Nematoda dominating. The composition of nematode species in the lagoon has not previously been studied. Using samples from 1979, 2013 and 2015, 50 nematode species and forms were identified in 1979, 32 in 2013 and 21 in 2015. The species composition of nematodes at different periods was significantly different. The average abundance of nematodes was 134 198 ind. m −2 in 2013 and 606 660 ind. m −2 in 2015.
Artemia spp. play a key role in hypersaline ecosystems. Artemia can live in a salinity range from... more Artemia spp. play a key role in hypersaline ecosystems. Artemia can live in a salinity range from 10 to 300-340 g/L, but in water bodies where salinity is between 10 and 100 g/L, it may be absent. Is the absence of Artemia in some Crimean lakes determined by the presence of predators or by salinity? To answer this question field long-term and experimental data collected in the Crimean lakes were used. With the least probability, the populations of Artemia existed in the lakes with a salinity of up to 50 g/L or above 300 g/L. Self-reproducing Artemia populations (all age stages) were most likely (≥80% of occurrence) noted in the salinity range of 150-200 g/L. Long-term monitoring in two lakes showed that in different years, a significant negative correlation of Artemia abundance with the numbers of amphipod Gammarus aequicauda and ostracod Eucypris mareotica was found in both lakes. This correlation can be explained by ostracod and amphipod predation on Artemia. In years without predator populations, the number of Artemia was higher by several times. Experiments showed that these amphipods and ostracods consume brine shrimps of different developmental stages. There are at least 12 crustacean species, 5 insect species, and 2 fish species, all listed in this paper, which inhabit Crimean hypersaline waters and can eat Artemia. Their predation on Artemia often is a main cause of its absence in the salinity range from 10 to 150 g/L.
Artemia spp. play a key role in hypersaline ecosystems. Artemia can live in a salinity range from... more Artemia spp. play a key role in hypersaline ecosystems. Artemia can live in a salinity range from 10 to 300-340 g/L, but in water bodies where salinity is between 10 and 100 g/L, it may be absent. Is the absence of Artemia in some Crimean lakes determined by the presence of predators or by salinity? To answer this question field long-term and experimental data collected in the Crimean lakes were used. With the least probability, the populations of Artemia existed in the lakes with a salinity of up to 50 g/L or above 300 g/L. Self-reproducing Artemia populations (all age stages) were most likely (≥80% of occurrence) noted in the salinity range of 150-200 g/L. Long-term monitoring in two lakes showed that in different years, a significant negative correlation of Artemia abundance with the numbers of amphipod Gammarus aequicauda and ostracod Eucypris mareotica was found in both lakes. This correlation can be explained by ostracod and amphipod predation on Artemia. In years without predator populations, the number of Artemia was higher by several times. Experiments showed that these amphipods and ostracods consume brine shrimps of different developmental stages. There are at least 12 crustacean species, 5 insect species, and 2 fish species, all listed in this paper, which inhabit Crimean hypersaline waters and can eat Artemia. Their predation on Artemia often is a main cause of its absence in the salinity range from 10 to 150 g/L.
Изучено влияние дозы гамма-облучения 2.5, 5.5 и 7.5 Гр, полученной цистами Artemia, на выход науп... more Изучено влияние дозы гамма-облучения 2.5, 5.5 и 7.5 Гр, полученной цистами Artemia, на выход науплиусов и постнауплиальную выживаемость рачков при 0, 9, 18, 36, 54, 62, 78 и 88 г/л. При этих же солёностях оценивали вышеуказанные параметры в условиях без облучения. Установлено, что скорость вылупления науплиусов из цист в первую очередь зависит от солёности, коэффициент детерминации равен 90%. Доза облучения не влияет на выход науплиусов при всех солёностях, кроме 54 г/л, когда была найдена достоверная негативная связь между долей вылупившихся науплиусов и дозой облучения. Выживаемость рачков из облученных цист зависела от солёности. В диапазоне солёности 9 – 52 г/л она была достоверно меньше, чем в диапазоне 62 – 88 г/л (дозы 2.5 и 5.5 Гр). Рачки, вышедшие из цист, получивших дозу 7.5 Гр, не доживали до 12 дня при солёности 88 г/л. Минимальная выживаемость рачков отмечена при солёности 54 г/л при всех дозах облучения, данная солёность может считаться для артемий критической, при ней происходит перенастройка механизма осморегуляции. Экологические эффекты в популяциях артемий могут проявляться, начиная с доз облучения 2.5 Гр. Изученные дозы облучения могут иметь и отдаленные по- следствия для популяции артемий в гиперсолёных водоёмах. Для корректной количественной оценки эффекта этих доз на популяции артемий необходимы исследования не только генерации рачков, которая вылупилась из облученных цист, но и 2–3 последующих поколений.
Salinity is one of the most important factors in aquatic ecosystems, but its filtering role in th... more Salinity is one of the most important factors in aquatic ecosystems, but its filtering role in the Diptera community species composition is still poorly studied. This issue was studied in the diverse Crimean water bodies. A total of 425 samples were collected from freshwater to hypersaline waters. In 73% of the 425 samples examined, representatives of Diptera were found; their larvae and pupae belonged to seven families. Сhironomid species composition was analyzed in 47 samples. The most common were Chironomidae, which were in 94% of samples with Diptera, Ceratopoganidae were in 8% of samples, Ephydridae were in 5% of samples, Simuliidae were in 4% of samples, Culicidae and Chaoboridae were in 4% of samples, and Syrphidae was in only one sample. A total of 14 Chironomidae genera and 21 species and forms were found; 9 of them are new for Crimea. Reduction of the dominance variants in the community, as well as the number of chironomid species, with increasing salinity may indicate an increase in the filtering role of salinity in the Diptera community species composition that is still poorly studied.
Our sustainable environmental management must be based on adequate ecological concepts. The quest... more Our sustainable environmental management must be based on adequate ecological concepts. The question arises: what concept is better to use for understanding and management of ecosystems? To look for an answer, we concentrate our attention on saline lakes. Every ecosystem has several alternative stable states and may demonstrate regime shifts, which are large, abrupt, persistent changes in the structure and function of a system. To understand the dynamics of ecosystems the Concept of Multiplicity of Ecosystem Alternative Stable States as a new ecological paradigm has been developed recently. The author analyzes the emerging paradigm using the case of saline lakes, and discusses how to base our adaptive environmental management on the developing paradigm. Diff erent issues of development of the concept and its application to salinology as a scientifi c basis of an integrated management of a saline lake and its watershed are discussed. The concept may serve as one of the key theoretical elements of the scientifi c basis in sustainable environmental management.
Filamentous green algae play an important functional role in element cycling and productivity in ... more Filamentous green algae play an important functional role in element cycling and productivity in the diff erent water bodies. In hypersaline lakes and lagoons of the Crimea, fi lamentous green algae are present and form bottom and fl oating mats that occupy large areas with high biomass, up to 4-5 kg (wet biomass)/m 2. Cladophora spp. dominated in those mats. Five species of fi lamentous green algae (Chlorophyta) in Lake Chersonesskoye: Cladophora vadorum (Aresch.) Kütz., C. siwaschensis C. Meyer, C. echinus (Biasol.) Kütz., Ulothrix implexa (Kütz.) Kütz., Rhizoclonium tortuosum (Dillw.) Kütz., and seagrass (Angiospermae) Ruppia cirrhosa (Petagna) Grande were found. Cladophora spp. and R. cirrhosa were found in the lake throughout the year, other types of algae were encountered episodically. In most cases the biomass of bottom mat exceeded that of the fl oating mat. In general, the total biomass of the bottom and fl oating mats in the lake areas at depths up to 30 cm was in a stable range of values from 100 to 290 mg (dry weight)/cm 2. Animal and infusorian average abundance in mats reach high values: infusorians-up to 15 000 000 ind./m 2 , Cletocamptus retrogressus (Copepoda, Harpacticoida)-up to 730 000 ind./m 2 , Eucypris mareotica (Ostracoda)-up to 91 000 ind./m 2 and Chironomidae larvae (Insecta, Diptera)-up to 140 ind./m 2. Those values were much higher than in the plankton.
The statement that the world’s ecosystems are
rapidly deteriorating due to human intervention and... more The statement that the world’s ecosystems are rapidly deteriorating due to human intervention and global warming is nowadays commonplace. Some of the ecosystems most heavily impacted are inland salt lakes. The salt lakes are among the most valuable and fascinating ecosystems on Earth, and their study has both basic scientifi c interest as well as applied aspects.
On the Crimean peninsula, there are more than 50 hypersaline water bodies, including the Sivash (... more On the Crimean peninsula, there are more than 50 hypersaline water bodies, including the Sivash (the Sea of Azov), the largest hypersaline lagoon in the world. Based on the literature and our own long-term research data (2000-2017), a review of the fauna of the hypersaline waters in the Crimea is presented, including 298 species of animals belonging to 8 phyla, 14 classes and 27 orders. The variety of phyla and classes within a particular range of salinity was shown to decrease significantly with an increase in salinity; 8 classes in 3 phyla can withstand salinities above 100 g/L, and only 4 classes (Branchiopoda, Hexanauplia, Ostracoda and Insecta) within 1 phylum (Arthropoda) occur at salinities above 200 g/L. The number of species found in a single sample also decreased with increasing salinity. However, in the range of 50-120 g/L, the number of species was mainly determined by a different set of factors. The abundance of animals in the hypersaline waters of the Crimea can be very high: e.g., Nematoda-up to 1.4•10 7 ind./m 2 , Harpacticoida-up to 3.5•10 6 ind./m 2 , Ostracoda-up to 5.8•10 5 ind./m 2 , and Moina salina-up to 1.3•10 6 ind./m 3. A characteristic feature of hypersaline water ecosystems is the fact that increases in salinity cause increasing amounts of benthic animals (Chironomidae, Harpacticoida, Ostracoda) to change their habitats from the bottom to the water column. At salinities above 120-150 g/L, there is almost no animal life at the bottom. Most of the species found in shallow hypersaline waters have a resting stage in their life cycle, which ensures their survival in abruptly changing environments, even those in ephemeral water bodies.
Гиперсоленые водоемы, соленость которых превышает 35 г/л, широко распространены на планете (гипе... more Гиперсоленые водоемы, соленость которых превышает 35 г/л, широко распространены на планете (гиперсоленые озера и лагуны, глубоководные "озера", поровые воды морских льдов) и относятся к числу наиболее экстремальных местообитаний Земли. В работе обобщены и проанализированы результаты собственных многолетних исследований экосистем гиперсоленых озер и лагун Крыма и литературные данные. Эти экосистемы уникальны как по физико-химическим показателям, так и по структуре и функционированию населяющей их биоты. В гиперсоленых водоемах температур-ный диапазон, в котором вода остается жидкой и может существовать жизнь, шире, чем в пресных или морских. При солености 350 г/л этот диапазон-от-35°С до +109°С. Видовое разнообразие эу-кариотных организмов с ростом солености резко убывает, а прокариотных увеличивается. В прес-новодных и морских экосистемах поступление энергии в экосистемы в основном обеспечивает ок-сигенный фотосинтез. В гиперсоленых озерах энергия поступает от трех групп фототрофов и разно-образных хемотрофов. Например, аноксигенный фотосинтез может обеспечивать до 85% поступающей в экосистему энергии, и его доля в общей первичной продукции при увеличении со-лености выше 100-160 г/л растет. Многие гиперсоленые водоемы, несмотря на экстремальность среды, являются высокопродуктивными. Данный парадокс можно объяснить двумя причинами: 1) высокими концентрациями биогенов и 2) высокой мелкомасштабной пространственно-времен-ной изменчивостью абиотических факторов. Это позволяет взаимодействовать противоположно направленным процессам и замыкать циклы внутри одного сообщества. Одним из механизмов осмоадаптации первичных продуцентов к высокой солености и ее резким колебаниям является вы-деление ими в среду экзополисахаридов. Их количество увеличивается с ростом солености и может составлять до 50-70% первичной продукции, что ведет к возрастанию роли гетеротрофных осмот-рофов в пищевых сетях. Дальнейшее изучение гиперсоленых местообитаний может расширить на-ши представления об организации жизни в экстремальной среде.
Citation: Zadereev E.S., Shadrin N.V. In search for common ground: studies of freshwater and sali... more Citation: Zadereev E.S., Shadrin N.V. In search for common ground: studies of freshwater and saline lakes. J. Sib. Fed.
—The dynamics of food chains upon changes in water salinity has been analyzed using the example o... more —The dynamics of food chains upon changes in water salinity has been analyzed using the example of six poly-and hyperhaline lakes in the Crimea. The results show that ecosystems of saline lakes are sensitive to the impact of external factors. Changes in weather conditions often lead to fluctuations of water salinity, which may cause a changeover in the hydrobiological regime of the lake. In lakes with high water salinity, the shortening of food chain takes place, and the cascade effect is observed in their dynamics.
Shadrin N. V., Anufriieva E. V. An ecosystem role of spatial and temporal inhomogeneity in feedin... more Shadrin N. V., Anufriieva E. V. An ecosystem role of spatial and temporal inhomogeneity in feeding of planktonic crustaceans // Ekosystemy. 2018. Iss. 14 (44). P. 119–128. The aggregated distribution of planktonic crustaceans and the presence of diurnal feeding rhythms of them are well known phenomena. At the same time, the significance of spatial heterogeneity and temporal variability in the feeding of crustaceans in the stable functioning of the system «phytoplankton – zooplankton» can not be considered sufficiently understood. Using numerous data from field and experimental studies, on the basis of mental and numerical models, the authors analyzed the possible ecosystem role of the spatial and temporal heterogeneity of feeding of planktonic crustaceans. The presence of diurnal feeding rhythms maximizes the productivity of microalgae and crustaceans, stabilizing the «phytoplankton – zooplankton» system and reducing the probability of its extinction. The formation of crustacean aggregation in plakton is determined by their motor reactions of animals to the concentration of algae. With a certain algorithm of the behavior of the crustaceans aggregation, the spatial heterogeneity of their feeding also leads to the maximization of the production of microalgae and crustaceans, and the stabilization of the «phytoplankton – zooplankton» system.
In the Crimea, there are many hypersaline lakes and lagoons, where Eucypris mareotica (Ostracoda)... more In the Crimea, there are many hypersaline lakes and lagoons, where Eucypris mareotica (Ostracoda), high halotolerant species, inhabit. Despite the wide distribution of the species and the abundance of its populations, little is known about the biology of E. mareotica, including its nutrition. Diversity of microalgae in gut of E. mareotica in Lake Chersonesskoye was studied. The crustaceans ate both phytoplankton and alga, which growth on cladophora filaments, as well as various small animals, but microalgae played a main role in their nutrition. The proportion of individuals, which had algae in intestines, ranged in a sample from 0 to 93%. In 335 analyzed individuals, 22 species of microalgae were found, which belong to 4 types, 4 classes and 11 orders. Of these, 4 species belong to the type Cyanobacteria, 3 – to Myzozoa, 4 – to Haptophyta, 11 – to Ochrophyta. The most common species was Peridinium cinctum. Given the availability of a wide variety of consumed microalgae, ostracod gut content analysis can be used to assess species diversity of microalgae in the lakes.
Lagoon Bardawil, belonging to the few hypersaline lagoons in the Mediterranean Sea, is located in... more Lagoon Bardawil, belonging to the few hypersaline lagoons in the Mediterranean Sea, is located in the middle of the Sinai coast. Composition, distribution, and seasonal dynamics of large planktonic tintinnids and foraminifera at 12 stations in the lagoon were studied in 2009 and 2010. Fifteen species of Ciliophora (Tintinnina) and two species of Foraminifera were identified. The occurrence of different species varied greatly in the study period: two species were found in 42% to 49% of all samples, two species in 21% to 23%, 4 species in 10% to 20%, and 10 species in 1% to 5%. Only three species were found throughout the year. The average total number of all recorded protozoa varied from 2333 ind./m3 (spring) to 13,733 ind./m3 (winter): Tintinnina from 1250 ind./m3 (spring) to 12,867 ind./ m3 (winter) and Foraminifera from 200 ind./m3 (autumn) to 1083 ind./m3 (spring). The distribution of total abundance of tintinnids and foraminifers in the lagoon area was close to random in summer and spring; during autumn and winter, it was aggregated. Tintinnid and foraminifera studies in Lagoon Bardawil were carried out previously (1985–2010); summarizing all data, it was found that interannual differences may be explained by stochastic causes and nondirected climate fluctuations.
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Papers by Nickolai Shadrin
намика численности и влияние разных факторов среды на Ostracoda в гиперсоленых озерах Крыма.
Показано, что в водоемах встречается только один представитель класса – Eucypris mareotica (Fischer,
1855). Вид отмечен в озерах Крыма при максимальной солености 300 г/л. Частота встречаемости
вида имеет обратную связь с соленостью. Рачки достигают высокой численности в планктоне
(650 тыс. экз./м3), бентосе (565 тыс. экз./м2) и плавучих матах нитчатых зеленых водорослей Cladophora
spp. (9.9 млн экз./на 1 кг сырой массы мата). Используя кальций и магний для построения сво-
их раковин, остракоды снижают концентрацию этих элементов в воде. Отмечена возможность ис-
пользования раковин остракод для палеоклиматических и палеолимнологических реконструкций.
на выход науплиусов и постнауплиальную выживаемость рачков при 0, 9, 18, 36, 54, 62, 78
и 88 г/л. При этих же солёностях оценивали вышеуказанные параметры в условиях без об-
лучения. Установлено, что скорость вылупления науплиусов из цист в первую очередь за-
висит от солёности, коэффициент детерминации равен 90%. Доза облучения не влияет на
выход науплиусов при всех солёностях, кроме 54 г/л, когда была найдена достоверная нега-
тивная связь между долей вылупившихся науплиусов и дозой облучения. Выживаемость
рачков из облученных цист зависела от солёности. В диапазоне солёности 9 – 52 г/л она бы-
ла достоверно меньше, чем в диапазоне 62 – 88 г/л (дозы 2.5 и 5.5 Гр). Рачки, вышедшие из
цист, получивших дозу 7.5 Гр, не доживали до 12 дня при солёности 88 г/л. Минимальная
выживаемость рачков отмечена при солёности 54 г/л при всех дозах облучения, данная со-
лёность может считаться для артемий критической, при ней происходит перенастройка ме-
ханизма осморегуляции. Экологические эффекты в популяциях артемий могут проявляться,
начиная с доз облучения 2.5 Гр. Изученные дозы облучения могут иметь и отдаленные по-
следствия для популяции артемий в гиперсолёных водоёмах. Для корректной количественной
оценки эффекта этих доз на популяции артемий необходимы исследования не только генера-
ции рачков, которая вылупилась из облученных цист, но и 2–3 последующих поколений.
и 88 г/л. При этих же солёностях оценивали вышеуказанные параметры в условиях без облучения. Установлено, что скорость вылупления науплиусов из цист в первую очередь зависит от солёности, коэффициент детерминации равен 90%. Доза облучения не влияет на выход науплиусов при всех солёностях, кроме 54 г/л, когда была найдена достоверная негативная связь между долей вылупившихся науплиусов и дозой облучения. Выживаемость
рачков из облученных цист зависела от солёности. В диапазоне солёности 9 – 52 г/л она была достоверно меньше, чем в диапазоне 62 – 88 г/л (дозы 2.5 и 5.5 Гр). Рачки, вышедшие из
цист, получивших дозу 7.5 Гр, не доживали до 12 дня при солёности 88 г/л. Минимальная выживаемость рачков отмечена при солёности 54 г/л при всех дозах облучения, данная солёность может считаться для артемий критической, при ней происходит перенастройка механизма осморегуляции. Экологические эффекты в популяциях артемий могут проявляться, начиная с доз облучения 2.5 Гр. Изученные дозы облучения могут иметь и отдаленные по-
следствия для популяции артемий в гиперсолёных водоёмах. Для корректной количественной оценки эффекта этих доз на популяции артемий необходимы исследования не только генерации рачков, которая вылупилась из облученных цист, но и 2–3 последующих поколений.
rapidly deteriorating due to human intervention and
global warming is nowadays commonplace. Some of
the ecosystems most heavily impacted are inland salt
lakes. The salt lakes are among the most valuable and
fascinating ecosystems on Earth, and their study has
both basic scientifi c interest as well as applied aspects.
The aggregated distribution of planktonic crustaceans and the presence of diurnal feeding rhythms of them are well known phenomena. At the same time, the significance of spatial heterogeneity and temporal variability in the feeding of crustaceans in the stable functioning of the system «phytoplankton – zooplankton» can not be considered sufficiently understood. Using numerous data from field and experimental studies, on the basis of mental and numerical models, the authors analyzed the possible ecosystem role of the spatial and temporal heterogeneity of feeding of planktonic crustaceans. The presence of diurnal feeding rhythms maximizes the productivity of microalgae and crustaceans, stabilizing the «phytoplankton – zooplankton» system and reducing the probability of its extinction. The formation of crustacean aggregation in plakton is determined by their motor reactions of animals to the concentration of algae. With a certain algorithm of the behavior of the crustaceans aggregation, the spatial heterogeneity of their feeding also leads to the maximization of the production of microalgae and crustaceans, and the stabilization of the «phytoplankton – zooplankton» system.
coast. Composition, distribution, and seasonal dynamics of large planktonic tintinnids and foraminifera at 12 stations in the lagoon were
studied in 2009 and 2010. Fifteen species of Ciliophora (Tintinnina) and two species of Foraminifera were identified. The occurrence of
different species varied greatly in the study period: two species were found in 42% to 49% of all samples, two species in 21% to 23%, 4
species in 10% to 20%, and 10 species in 1% to 5%. Only three species were found throughout the year. The average total number of all
recorded protozoa varied from 2333 ind./m3 (spring) to 13,733 ind./m3 (winter): Tintinnina from 1250 ind./m3 (spring) to 12,867 ind./
m3 (winter) and Foraminifera from 200 ind./m3 (autumn) to 1083 ind./m3 (spring). The distribution of total abundance of tintinnids and
foraminifers in the lagoon area was close to random in summer and spring; during autumn and winter, it was aggregated. Tintinnid and
foraminifera studies in Lagoon Bardawil were carried out previously (1985–2010); summarizing all data, it was found that interannual
differences may be explained by stochastic causes and nondirected climate fluctuations.
намика численности и влияние разных факторов среды на Ostracoda в гиперсоленых озерах Крыма.
Показано, что в водоемах встречается только один представитель класса – Eucypris mareotica (Fischer,
1855). Вид отмечен в озерах Крыма при максимальной солености 300 г/л. Частота встречаемости
вида имеет обратную связь с соленостью. Рачки достигают высокой численности в планктоне
(650 тыс. экз./м3), бентосе (565 тыс. экз./м2) и плавучих матах нитчатых зеленых водорослей Cladophora
spp. (9.9 млн экз./на 1 кг сырой массы мата). Используя кальций и магний для построения сво-
их раковин, остракоды снижают концентрацию этих элементов в воде. Отмечена возможность ис-
пользования раковин остракод для палеоклиматических и палеолимнологических реконструкций.
на выход науплиусов и постнауплиальную выживаемость рачков при 0, 9, 18, 36, 54, 62, 78
и 88 г/л. При этих же солёностях оценивали вышеуказанные параметры в условиях без об-
лучения. Установлено, что скорость вылупления науплиусов из цист в первую очередь за-
висит от солёности, коэффициент детерминации равен 90%. Доза облучения не влияет на
выход науплиусов при всех солёностях, кроме 54 г/л, когда была найдена достоверная нега-
тивная связь между долей вылупившихся науплиусов и дозой облучения. Выживаемость
рачков из облученных цист зависела от солёности. В диапазоне солёности 9 – 52 г/л она бы-
ла достоверно меньше, чем в диапазоне 62 – 88 г/л (дозы 2.5 и 5.5 Гр). Рачки, вышедшие из
цист, получивших дозу 7.5 Гр, не доживали до 12 дня при солёности 88 г/л. Минимальная
выживаемость рачков отмечена при солёности 54 г/л при всех дозах облучения, данная со-
лёность может считаться для артемий критической, при ней происходит перенастройка ме-
ханизма осморегуляции. Экологические эффекты в популяциях артемий могут проявляться,
начиная с доз облучения 2.5 Гр. Изученные дозы облучения могут иметь и отдаленные по-
следствия для популяции артемий в гиперсолёных водоёмах. Для корректной количественной
оценки эффекта этих доз на популяции артемий необходимы исследования не только генера-
ции рачков, которая вылупилась из облученных цист, но и 2–3 последующих поколений.
и 88 г/л. При этих же солёностях оценивали вышеуказанные параметры в условиях без облучения. Установлено, что скорость вылупления науплиусов из цист в первую очередь зависит от солёности, коэффициент детерминации равен 90%. Доза облучения не влияет на выход науплиусов при всех солёностях, кроме 54 г/л, когда была найдена достоверная негативная связь между долей вылупившихся науплиусов и дозой облучения. Выживаемость
рачков из облученных цист зависела от солёности. В диапазоне солёности 9 – 52 г/л она была достоверно меньше, чем в диапазоне 62 – 88 г/л (дозы 2.5 и 5.5 Гр). Рачки, вышедшие из
цист, получивших дозу 7.5 Гр, не доживали до 12 дня при солёности 88 г/л. Минимальная выживаемость рачков отмечена при солёности 54 г/л при всех дозах облучения, данная солёность может считаться для артемий критической, при ней происходит перенастройка механизма осморегуляции. Экологические эффекты в популяциях артемий могут проявляться, начиная с доз облучения 2.5 Гр. Изученные дозы облучения могут иметь и отдаленные по-
следствия для популяции артемий в гиперсолёных водоёмах. Для корректной количественной оценки эффекта этих доз на популяции артемий необходимы исследования не только генерации рачков, которая вылупилась из облученных цист, но и 2–3 последующих поколений.
rapidly deteriorating due to human intervention and
global warming is nowadays commonplace. Some of
the ecosystems most heavily impacted are inland salt
lakes. The salt lakes are among the most valuable and
fascinating ecosystems on Earth, and their study has
both basic scientifi c interest as well as applied aspects.
The aggregated distribution of planktonic crustaceans and the presence of diurnal feeding rhythms of them are well known phenomena. At the same time, the significance of spatial heterogeneity and temporal variability in the feeding of crustaceans in the stable functioning of the system «phytoplankton – zooplankton» can not be considered sufficiently understood. Using numerous data from field and experimental studies, on the basis of mental and numerical models, the authors analyzed the possible ecosystem role of the spatial and temporal heterogeneity of feeding of planktonic crustaceans. The presence of diurnal feeding rhythms maximizes the productivity of microalgae and crustaceans, stabilizing the «phytoplankton – zooplankton» system and reducing the probability of its extinction. The formation of crustacean aggregation in plakton is determined by their motor reactions of animals to the concentration of algae. With a certain algorithm of the behavior of the crustaceans aggregation, the spatial heterogeneity of their feeding also leads to the maximization of the production of microalgae and crustaceans, and the stabilization of the «phytoplankton – zooplankton» system.
coast. Composition, distribution, and seasonal dynamics of large planktonic tintinnids and foraminifera at 12 stations in the lagoon were
studied in 2009 and 2010. Fifteen species of Ciliophora (Tintinnina) and two species of Foraminifera were identified. The occurrence of
different species varied greatly in the study period: two species were found in 42% to 49% of all samples, two species in 21% to 23%, 4
species in 10% to 20%, and 10 species in 1% to 5%. Only three species were found throughout the year. The average total number of all
recorded protozoa varied from 2333 ind./m3 (spring) to 13,733 ind./m3 (winter): Tintinnina from 1250 ind./m3 (spring) to 12,867 ind./
m3 (winter) and Foraminifera from 200 ind./m3 (autumn) to 1083 ind./m3 (spring). The distribution of total abundance of tintinnids and
foraminifers in the lagoon area was close to random in summer and spring; during autumn and winter, it was aggregated. Tintinnid and
foraminifera studies in Lagoon Bardawil were carried out previously (1985–2010); summarizing all data, it was found that interannual
differences may be explained by stochastic causes and nondirected climate fluctuations.