Microbial reaction rates and bacterial communities in sediment surrounding burrows of two nereidid polychaetes (Nereis diversicolor and N. virens)

The effects of infaunal mode of life on sediment properties, microbial reaction rates, as well as abundance and composition of bacterial communities were studied in sediment surrounding burrows (mucus lining, oxidised wall, ambient anoxic and surface sediment) of two closely related, but behaviourally different, nereidid polychaete worms: the facultative suspension-feeder Nereis (Hediste) diversicolor and the obligate deposit-feeder Nereis (Neanthes) virens. Burrow sediment of the two species was collected from two adjacent (50 m distance) shallow sandy locations (Kertinge Nor, Denmark). The burrow lining and wall of both polychaete species were enriched in organic matter originating from mucous secretions by the inhabitants and phytoplankton trapped through irrigation. This was more evident for N. diversicolor that shows a significantly higher irrigation rate than N. virens. Both the organic matter mineralisation rates (based on anaerobic incubations) and bacterial abundance were higher along the burrow linings and walls. However, accumulation of porewater TCO₂ and dissolved organic carbon in sediments adjacent to burrows increased most rapidly in the presence of N. diversicolor, suggesting higher heterotrophic activity associated with this species. Surprisingly, bacterial abundance was lower around burrows of N. diversicolor than those from N. virens indicating that burrow environments from the first species harbour a more active bacterial community. Molecular fingerprints of the 16S rRNA gene from bacterial communities showed that the composition of the burrow linings and walls resembled the ambient anoxic sediment rather than the oxic sediment surface. On the other hand, the bacterial fingerprints of the sediment surrounding the burrows of the two polychaete species were markedly different suggesting either a site-specific difference in sediment parameters or a significant species-specific impact of the burrow inhabitants.     

Patterns in the spatial arrangements of polychaetes and bivalves in intertidal sandflats

Spatial autocorrelation correlograms based on Moran's coefficient were constructed for common polychaetes (Goniada emerita, Heteromastus filiformis, Macroclymenella stewartensis, Boccardia spp. and Magelona? dakini)_and bivalves (Nucula hartvigiana, Soletellina siliqua and Tellina liliana) collected from intertidal sandflats of Manukau Harbour (New Zealand) during October, 1987. Patterns of heterogeneity on a scale smaller than inter-sample distance, homogenous density patches (5 to 30 m radius) and gradients in abundance running through sample sites (9 000 m²) were identified. Patterns could be defined even for species with distributions which, based on the variance: mean ratio test, were not significantly different from random. The possible influence on two of the study sites of sediment disturbances generated by feeding rays is discussed. Identification of spatial patterns is considered an important aspect of the design of surveys and manipulative field experiments.     

Distributions and population structures of two intertidal estuarine polychaetes in the lower St. Lawrence Estuary,with special reference to environmental factors

An intensive study of the spatial distribution ofNereis virens (Sars) andNephtys caeca (Fabricius) was conducted during the spring and autumn of 1986 in the lower St. Lawrence estuary. Statistical analysis showed that spatial variations in density, individual body weight and sexual maturity, particularly in the case ofNereis virens, are correlated with the intertidal level, with certain sediment characteristics, and with the thickness of the colonizable sediment layer. The density ofN. virens increases in an offshore-onshore direction, whereas that ofNephtys caeca decreases in the same direction. For both species, mean body weight increases downshore from the upper intertidal level. Other specific relationships exist in relation to sediment characteristics. Sexually matureNereis virens are found only at the lower intertidal level; sexual maturity inNephtys caeca was not studied. There were no changes in spatial distribution patterns between spring and autumn. The spatial distribution ofNereis virens parallels depth contours and may reflect its ability to inhabit environments which become more physically unstable in an offshore-onshore direction. This spatial distribution is consistent with a model whereby larvae are recruited in the upper intertidal zone and juveniles migrate downshore.     

Reproductive success,relative abundance and population structure of two species of Nephtys in an estuarine beach

During 1978 and 1979 specimens of Nephtys hombergii in the River Tyne estuary (North East England) became gravid during the winter but did not spawn in the spring breeding season; instead their gametes were resorbed. The drastic effects of these spawning failures were apparent in the population structure in 1980, when the 1978 and 1979 year-classes were shown to be virtually absent, by the size of the individuals in the population and the numbers of growth lines in their jaws. The population structure in 1975, by contrast, indicated that recruitment during the preceding 4 to 5 yr had been good. Spawning was also effective in 1980, and an 0 group was detected in August 1980. Comparable data has been obtained for N. caeca, which occurs in the same beach. It shows that recruitment of this species during 1976–1980 was consistently good, whereas analysis of the age-class frequencies suggests that recruitment of N. caeca was poor in 1973 and 1975. The dominance relationship of the two species in the beach has been reversed during the period 1975–1980. It is suggested that the sympatric distribution of the two species is maintained in part by periodic reproductive failure. The causes of this are not yet known; possible reasons, including the extremely cold conditions experienced in 1978–1979 are discussed. The difference in frequency of the 1978, 1979 and 1980 year classes will now permit a rigorous evaluation of the relationship between the number of growth lines in the jaws and age in N. hombergii.     

Temperature sensitivity of metabolism in offshore and intertidal onuphid polychaetes

Acclimated metabolism-temperature curves have been constructed for 4 populations of the intertidal onuphid Diopatra cuprea, and for the 2 offshore species Hyalinoecia tubicola and H. artifex. The intertidal species shows greater temperature sensitivity than its offshore relative, despite its presumed adaptation to thermally unstable habitats. Temperature changes considerably in excess of natural fluctuations do not greatly alter metabolic rates in Hyalinoecia. However, the range of thermal tolerance in these two species is considerably reduced.     

Uptake of L-valine and other amino acids by the polychaete Nereis virens

For valine uptake by the polychaete Nereis virens Sars, the kinetic constants were: V _max=355 nmol g^-1 fresh weight h^-1, K _m=20 M. Leucine and some other amino acids acted as partial inhibitors of valine uptake. Valine uptake rate was 78% higher at 21.5 S than at 14 S. The major portion of valine absorbed by the polychaete could be extracted as free valine, with 6.5 to 15.6% being respired, and 3.6 to 9.5% incorporated into proteins. Calculations indicate that 7 to 12% of the metabolism of N. virens may be sustained by uptake of glycine and aspartic acid from natural concentrations. It is suggested that uptake of amino acids by this worm is important in the nitrogen cycling of marine sediments.     

Measurement of the adenylate energy charge in Nereis diversicolor and Nephtys sp. (Polychaeta: Annelida):

ATP-content and adenylate energy charge (AEC) ratios were determined in two polychaete species (Neries diversicolor and Nephytys sp.), sampled in ten stations along the heavily polluted Western Scheldt estuary (N. Belgium, S. Holland). The samples were taken between 27 December 1982 and 6 January 1983. Nereis diversicolor was also sampled in an unpolluted brackish water pond, and subjected to artificial stress by drying the organisms on filter paper. Adenine nucleotide levels were determined using the firefly bioluminescence reaction. The light emission was measured with the integration mode. As the Constant Light Signal reagent used contained AMP and probably ADP itself, both myokinase and pyruvatekinase had to be inactivated before the assay. The use of pepsin in acidic conditions to denaturate these enzymes is discussed. For both N. diversicolor and Nephtys sp., a significant relation between ATP-content and fresh weight is found in most samples. Within each species, ATP-content per g fresh weight is dependent on the sampling method, but it is not significantly different between stations. It is higher in Nephtys sp. from the W. Scheldt (130. 8 10^-5 g ATP/g fresh weight) than in N. diversicolor from the Dievengat (83.9 10^-5 g ATP/g fresh weight). This value in turn is significantly higher than that for N. diversicolor in the W. Scheldt (64.0 10^-5 g ATP/g fresh weight). In the drying experiment, AEC gradually decreases with increasing drying time. In the field, AEC is generally high and not significantly different between the three populations. AEC ratios also do not differ between stations within each population. It is argued that field monitoring of AEC in invertebrates is not valuable as a pollution assessment tool for two reasons. In polluted stations, only pollutant-resistant species will be found, and there is evidence that the maintenance of a stable population is impossible when the individuals constantly have low AECs.     

Elimination of Pentachlorobiphenyls by Nereis virens (Polychaeta) in the Laboratory and the Marine Environment

Fifty sandworms, Nereis virens, were maintained in a closed aquarium system with continuous charcoal filtration at 12°C and 27.6‰ S. They were dosed orally for 10 consecutive days with a mixture of three pentachlorobiphenyls: 35 ng 2,4,6,2',4'-pentachloro[U-¹⁴C]biphenyl, 106 ng 2,4,5,2',5'-pentachlorobiphenyl, and 106 ng 2,3,4,2',5'-pentachlorobiphenyl per g of Nereis virens per day. At the end of the dosing period the accumulated compounds were measured in 5 worms, the remaining 45 specimens were divided into three groups for determining the PCB elimination under different conditions for 14 to 26 weeks: in the laboratory with feeding, in the laboratory without feeding, and in a cage moored in the Weser estuary.

The accumulation percentages for these PCB compounds were 41, 26 and 4% respectively. Times for the initial 50% decrease t_e50 were 4.4, 2.8 and 1.9 weeks respectively, and appeared the same in all three experimental groups. However, in the laboratory experiments the metabolites of the ¹⁴C-labelled compound amounted to ∼60%, compared to the field experiment with ∼30%. This extended the t_e50 for ¹⁴C activity (metabolites included) to ∼9 weeks in the laboratory experiments.     

Comparison of mussel bed community between two intertidal mytilids Septifier virgatus and Hormomya mutabilis

Mussel bed community structure of two intertidal mytilids, Septifer virgatus (Wiegmann) and Hormomya mutabilis (Gould), whose beds were contiguous vertically on a rocky intertidal shore (Wakayama Prefecture, Japan), was compared between 1982 and 1983. In the upper S. virgatus bed, crustaceans and bivalves were dominant in terms of both number of individuals and biomass. There were three barnacle species representative of the epizoans, two isopods and one amphipod as mobile fauna, and two bivalves as infauna. The lower H. mutabilis bed supported virtually no epizoans or mobile fauna. Infaunal free-ranging polychaetes and sipunculids were dominant in terms of both number of individuals and biomass. The H. mutabilis bed contained a much greater amount of sediment than did the S. virgatus bed, and the interstices among individual H. mutabilis and among their byssal threads were filled with sediment. The biomass of six of nine species dominant in the S. virgatus bed was negatively correlated with the amount of sediment. Recruitment of these faunal assemblages into artificial mussel clumps was examined in mussel enclosure experiments, and a negative sediment effect in H. mutabilis clumps was detected for one isopod and one limpet species. Factors causing the differences between two mussel bed communities are discussed, focusing on the effects of sediment.     

Oxygen and carbon dioxide exchange in the polychaete Nereis virens: influence of ventilation activity and starvation

The influence of ventilation activity and starvation on O₂ uptake and CO₂ production in the polychaete Nereis virens Sars was investigated during September 1986 using worms collected on intertidal flats outside the Nærå Strand estuary, Denmark. The activity level, measured as ventilation rate, , was linearly related to active O₂ uptake, , for worms inhabiting artificial burrows (i.e. tubes) in the laboratory. at 16°C was two and four times the extrapolated standard O₂ uptake ( =0) when was 100 and 500 ml g^-1 h^-1, respectively. The use of tubes had no significant effect on N. viren's temporal ventilation pattern, D_v, compared to natural burrows in sediment. The ventilation rate, , however, was 2 to 3 times higher in tubes than in burrows. Starvation affected both ventilation and gas exchange. increased slightly during the first six days remaining constant thereafter. D_v, on the othe hand, decreased during the first six days followed by a gradual increase to Day 20. The observed decrease in D_v (%) from Day 0 to 1 was attributed to insufficient acclimation of the worms. The time integrated ventilation rate, × D_v, increased gradually throughout the 20 d starvation period. and declined rapidly during the first days of starvation. After 10 d the gas exchange reached steady levels at about 50% of the initial rate. The observed decrease in metabolic rate during starvation was explained by a rapid initial reduction in specific dynamic action (SDA) followed by a gradual exhaustion of readily available metabolic reserves, e.g. glycogen and lipids.     

Population dynamics and secondary production in an estuarine population of Nephtys hombergii (Polychaeta: Nephtyidae)

From July 1978 to March 1980, a study was made on the distribution, population dynamics and secondary production of Nephtys hombergii Audouin et Edw. occurring in the sublittoral industrialised region of Southampton Water in south England. The distribution of the worm was related to the silt content and copper level of the sediment, the greatest densities of N. hombergii being found in sediment containing 60 to 100% silt. Breeding occurred at a low level throughout the year, with a maximum in July to September and November to January in the second year of growth. Spawning occurred when the oocytes measured 200m in diameter, and unshed gametes were resorbed. Annual production varied between 0.092 and 4.32 g C m^-2 yr^-1 (ash-free dry weight) and amounted to 1.9–39.4% of the total macrofaunal production at the sampling stations. The production:biomass (P:B) ratio of the species varied between 1.6 and 2.9.     

Juvenile growth of the polychaete Nereis virens feeding on a range of marine vascular and macroalgal plant sources

A laboratory experiment was conducted to examine variation of juvenile growth (% d^-1) of the polychaete Nereis virens (Sars) in relation to tidal flat plant species as food sources. We used vegetable materials (algae and vascular plants) which are carried along by tidal currents and are found abundantly at the upper tidal level. Juveniles (2-yr-old) markedly increased in wet weight with the algae Laminaria longicruris (weight-specific growth rate : 1.7% d^-1) and Enteromorpha intestinalis (: 1.6% d^-1) as food sources. A higher value of assimilation efficiency was observed for algal species (L. longicruris 55.1±7.9%; E. intestinalis 54.8±0.5%; Fucus vesiculosus 40.6%) than for marine vascular plants (Spartina alterniflora 26.8±10.9%; Zostera marina 1.4%). The digestion of marine vascular species lasts longer (19 to 38 h) than that of algal species. All these characteristics (growth, assimilation efficiency and duration of the digestive process) seem to correlate positively with lignin and cellulose concentrations in the plant structure.     

Histochemical demonstration of mercury in the intestine,nephridia and epidermis of the marine polychaete Nereis virens exposed to inorganic mercury

Marine polychaetes Nereis virens (Sars) were exposed to 9 ppb Hg as mercuric chloride in the aquarium water. Concentrations of mercury in the water and in the worms were monitored using radiolabelled mercury. After 11 d, the average mercury concentration in the nereids was 8.41 ppm Hg and the bioconcentration factor was calculated to be 930. Accumulations of mercury in the tissues were made visible for light and electron microscopy by autometallographic silver enhancement. Mercury was demonstrated in the intestine, nephridia, epidermis and cuticula. In the intestine, mercury was found to be located predominantly in the apical part of the epithelial cells. In the nephridia, mercury deposits were apparent in the peritoneal cells of the nephridial tubules. Silver-enhanced mercury was also observed at the epicuticula, in the collagen fibres of the endocuticula and in the epidermal basal cells. Intracellularly, the observed mercury accumulations were localised predominantly in lysosomes. Extracellularly, mercury was observed in the basal laminae of the intestine and the epidermis, and also in the intestinal peritrophic membrane. How N. virens copes with mercury toxicity is discussed.     

Metabolic enzymes in coelomic cells (eleocytes) of the polychaete Nereis virens: sex specific changes during sexual maturation

The activities of some enzymes of the intermediary metabolism and the content of soluble protein and carbohydrate (glycogen plus free glucose) were measured in one type of coelomic cells (eleocytes) of the polychaete Nereis virens. Specimens used in this study were collected between 1989 and 1991 in Oosterscheldt Bay, The Netherlands, and divided into six different stages of sexual maturation as determined by the mean oocyte volume. In both sexes, the soluble protein content in eleocytes of immature individuals (11 mg ml^–1 cell vol) increased three-fold. In prespawning N. virens the soluble protein content decreased to less than 2 mg protein ml^–1 cell vol in females but not in males. In both sexes, the carbohydrate content decreased continuously from immature [300 mol glucose equivalent (equiv) ml^–1 cell vol] to prespawning individuals (< 40 mol glucose equiv ml^–1 cell vol). During the time course of maturation, the specific activities (expressed as units mg^–1 protein) of pyruvate kinase, phosphoenolpyruvate carboxykinase, malate dehydrogenase, alanine aminotransferase and glutamate dehydrogenase decreased in both sexes. A transient increase in the specific activities was found for glycogen phosphorylase and aspartate aminotransferase. No major changes were found for hexokinase, lactase dehydrogenase, glucose-6-phosphate dehydrogenase and malic enzyme. Sex specific differences were found for the activities of citrate synthase and isocitrate dehydrogenase, which were higher in males. the specific activities of the latter enzyme increased more than ten-fold in males, but only four-fold in female eleocytes during maturation. In eleocytes of prespawning females, the activities of most enzymes showed extremely high variations not found in prespawning males. For two enzymes of fatty acid catabolism, -hydroxyacyl-CoA dehydrogenase and -hydroxybutyrate dehydrogenase, only traces of activities were detected, suggesting the absence of significant fatty acid catabolism in the eleocytes. Compared to the eleocytes, the body wall tissue showed ten-fold higher activities of phosphofructokinase, whereas the eleocytes displayed higher activities of the amino acid interconverting enzymes glutamate dehydrogenase and alanine aminotransferase and the glyconeogenic enzyme phosphoenolpyruvate carboxykinase. Citrate synthase activities were similar for both tissues. In the coelomic fluid of N. virens, glucose (< 0.1 to 3.5 mM) and d-lactate (0.1 to 4 mM) were present and represent exogenous substrates for the eleocyte metabolism.     

Arsenic speciation in polychaetes (Annelida) and sediments from the intertidal mudflat of Sundarban mangrove wetland, India

This paper documents the concentration of total arsenic and individual arsenic species in four soft-bottom benthic polychaetes (Perenereis cultifera, Ganganereis sootai, Lumbrinereis notocirrata and Dendronereis arborifera) along with host sediments from Sundarban mangrove wetland, India. An additional six sites were considered exclusively for surface sediments for this purpose. Polychaetes were collected along with the host sediments and measured for their total arsenic content using inductively coupled plasma mass spectrometry. Arsenic concentrations in polychaete body tissues varied greatly, suggesting species-specific characteristics and inherent peculiarities in arsenic metabolism. Arsenic was generally present in polychaetes as arsenate (As^V ranges from 0.16 to 0.50 mg kg^?1) or arsenite (As^III ranges from 0.10 to 0.41 mg kg^?1) (30–53 % as inorganic As) and dimethylarsinic acid (DMA^V <1–25 %). Arsenobetaine (AB < 16 %), and PO₄-arsenoriboside (8–48 %) were also detected as minor constituents, whilst monomethylarsonic acid (MA^V) was not detected in any of the polychaetes. The highest total As (14.7 mg kg^?1 dry wt) was observed in the polychaete D. arborifera collected from the vicinity of a sewage outfall in which the majority of As was present as an uncharacterised compound (10.3 mg kg^?1 dry wt) eluted prior to AB. Host sediments ranged from 2.5 to 10.4 mg kg^?1 of total As. This work supports the importance of speciation analysis of As, because of the ubiquitous occurrence of this metalloid in the environment, and its variable toxicity depending on chemical form. It is also the first work to report the composition of As species in polychaetes from the Indian Sundarban wetlands.     

Variations in time budget of the polychaete Nereis virens as a function of density and acclimation after introduction to a new burrow

Behavioural patterns of Nereis virens (Sars) were monitored in the laboratory to determine variations in the time budget (i.e., percentage of time spent in various activities) as a function of density and acclimation period (number of days following the introduction of worms into experimental enclosures). Experiments were carried out from 17 June to 13 August 1989, using worms collected from intertidal sand flats of l'Anse à l'Orignal in the lower Saint Lawrence estuary, Canada. Inactivity, locomotion and irrigation were, in that order, the most frequent behaviours for solitary individuals. Correlations between the time spent in the various activities and time of day indicated a general increase in activity during the night (21.00 to 06.00 hrs). Locomotory activity increased at night, inactivity during the daytime. A general sequence of behaviour of N. virens was revealed. Inactivity, locomotion and irrigation were still the most frequent activities for individuals observed in high-density conditions, but their respective importance differed significantly (locomotion, irrigation and inactivity, in that order). There was also less variability in the time spent for each behaviour in the high-density aquarium. Comparisons between behaviour and time of day suggested fewer correlations among the different components of the time budgets under conditions of high density. Finally, the time budget varied but little over time (number of days alloved for acclimation) in the low-density aquarium as opposed to the high-density aquarium. Our study revealed that population density and acclimation are important in determining behavioural patterns of N. virens.     

Photoperiodic control of growth and segment proliferation by Nereis (Neanthes) virens in relation to state of maturity and season

The effects of two fixed photoperiodic regimes on the rate of somatic growth and segment proliferation in the semelparous polychaete Nereis (Neanthes) virens Sars has been investigated. The two photoperiods (16 h light:8 h dark and 8 h light:16 h dark, hereafter LD 16:8 and LD 8:16) were close to the extremes experienced naturally by N. (N.) virens in the course of a year. The experiments were carried out during the ambient winter and all worms (including four-setiger larvae raised out of season) showed elevated feeding, growth and enhanced segment-proliferation rates when reared under LD 16:8, compared to worms reared under LD 8:16. The rate of replacement of lost segments after caudal ablation was also higher under LD 16:8. The number of segments present when the segment proliferation rate had fallen to zero was higher in individuals grown from birth under LD 16:8 compared to those grown under LD 8:16. Feeding activity showed a degree of spontaneous recovery under LD 8:16 from January onwards, but remained lower than under LD 16:8. This difference continued into the following spring, and was not attributable to differences in sexual maturity. We conclude that the rate of feeding in N. (N.) virens and other indicators of somatic growth rate such as rates of caudal regeneration and segment proliferation are directly influenced by the photoperiod, but that the seasonal cycle of growth also includes a circa-annual component modifying the response to static photoperiods according to the time of year. Received: 20 October 1998 / Accepted: 4 February 1999     

A comparison of spatial learning and memory capabilities in intertidal gobies

For the majority of animals, the ability to orient in familiar locations is a fundamental part of life, and spatial memory allows individuals to remember key locations such as food patches, shelter, mating sites or areas regularly occupied by predators. This study determined if gobies collected from rocky platforms and sandy beaches differ in their ability to learn and memorise the locations of tide pools in a simulated rocky intertidal zone. Intertidal rock pool gobies show acute homing abilities and, therefore, should be expected to display superior learning and memory capabilities. In contrast, it is unlikely that natural selection would favour similar learning skills in sandy shore fishes because they simply shift back and forth with the tides. The learning abilities of gobies were tested using small replica rock platforms, containing four tide pools that retained varying depths of water at simulated low tide. Gobies were categorised as having learnt the task if they were able to consistently locate the tide pool that retained the most water at simulated low tide as the pool with the most favourable conditions. Rock pool species were able to locate the deepest pool to wait out low tide for ~95 % of the trials, while species from sandy shores were found in the deepest pool ~10 % of trials. Despite repeated stranding, sandy shore fish continued to follow the tide out. We propose that rock pool species memorised the location of rock pools during simulated high tide enabling them to relocate the best refuge for low tide.     

Parameters of light-dependent photosynthesis for phytoplankton size fractions in temperate estuarine and coastal environments

Photosynthetic parameters for netplankton (>22 m) and nanoplankton (<22 m) varied over similar ranges but exhibited different seasonal and geographic patterns of variation. Nanoplankton a was relatively constant (0.06 mg C [mg Chl · h]^-1 [E m^-2 s^-1]^-1), but P _m ^B (mg C [mg Chl · d]^-1) was an exponential function of temperature independent of nutrient concentration and vertical stability in the euphotic zone. The temperature function gives a P _m ^B of 24 at 25°C for nanoplankton growing in an estuarine environment characterized by high nutrient concentrations and a shallow, stratified euphotic zone. Variations in netplankton a and P _m ^B were less predictable and were not correlated with temperature, nutrients or vertical stability. Chain forming diatoms with small cells were able to achieve high (0.10 to 0.15) and P _m ^B (20 to 24) that were 3 to 5 times higher than large-celled diatoms and dinoflagellates were able to achieve.     

Transport of pollutants in two estuarine systems on the coast of Georgia

The aim of the present study was to examine the distribution of pollutants in two coastal systems in Georgia: (1) Kubitskali river which flows into the Black sea through the city of Batumi and is polluted mainly from the effluents of an oil refinery; (2) Paliastomi lake, which is a shallow water body at the south-east of the city of Poti. During 2000–2001, two samplings took place in each system, one in the low-flow period and one in the high-flow period. During these samplings, pH, temperature, dissolved oxygen, and salinity were measured in situ, whereas water samples were collected for the analysis of trace metals, nutrients, and organic pollutants with standard methods. The results of the measurements indicate the significant pollution of both systems by ammonia and in the case of Kubitskali River also by oil products. The need for a sustainable management plan of the activities taking place in the river basin is urgent.