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26
January
2022

Estimation of water ecosystem structural-functional changes as a result of climate changes

O. Zhukova

Ph.D., docent of the department “Health and Environment”

Luchytskyi Yaroslav

Luchytskyi Vladyslav

student

Kyiv National University of Construction and Architecture

ЕКОЛОГІЯ (Екологічна безпека)

 Estimation of water ecosystem structural-functional changes as a result of climate changes

The problem of global climate change began to attract special attention in 1980s. In the middle of 1990s scientists from all over the world on the basis of long term analyses came up to a conclusion that human beings have serious impact on the occurring climate changes. In the middle of the first decade, it was determined by calculating the damage from natural disasters that 90% of climatic changes are conditioned by the anthropogenic factors and only 10% of these changes are of natural origin. [1]

Climate of our planet is a complicated system which changes due to the interaction processes between atmosphere, hydrosphere and humanity. These elements are in permanent and balanced interaction which is being destroyed nowadays because of anthropogenic impact on the biosphere and its constituents – natural types of ecosystem. Functioning of the ecosystems is intended to energy joining, storing the internal wholeness of its structure organization. In case of big gradient presence between the energy reserves of biosphere separate blocks, imbalance occurs which leads to a decrease of internal balance and increase of entropy indices. Natural ecosystems are not able to provide necessary stabilization anymore; therefore, external factors react accordingly transferring the energy in different directions. It leads to the appearance of heavy showers, storms, whirlwinds, the rise of average annual temperature indices and climatic indices amplitude changes increase, other cataclysms. When the entropy index exceeds the indices of system organization internal condition and this system is not able to withstand the external impact, connections are destroyed and system comes apart.

On the modern stage of civilization development, characterized by a rapid growth of population on the globe and increased load on natural resources of our planet, the questions of rational usage of water and providing it to the population and economic sectors are becoming extremely relevant. In the first place, it concerns Ukraine which is among the countries with insufficient water supply for one inhabitant. Current development condition of Ukraine is characterized by worsening of the ecological state of all the biosphere constituents. Special attention to the issue of global climate change was given on the Second World Climate Conference in Geneva (November, 1990) and on the 21st International Water Services Congress that was held in Madrid (September, 1997). In particular, it was mentioned that the increase of the global air temperature for 2-3 ºС is prognosticated in the next 20-40 years. The largest warming (up to 5-6 ºС) will take place in high latitudes and in zones of moderate and frigid climate. Possible consequences of climate change will inevitably affect the conditions of water ecosystems of the planet as they are the most sensitive ones to climate changes. [2, 4]

Direct connection between the quality of drinkable water and human’s health was determined long time ago. According to World Health Organization data, about 75% of human’s illnesses are caused by drinking the water of low quality and using the water in household which does not meet the hygienic norms. [3]

It is being predicted that the increase of water temperature, growth of rainfall intensity and longer periods of low flow will intensify many forms of water pollution (including the pollution by pumps, organic matters, pathogens, pesticides), salt and thermal pollution which will cause the eutrophication of basins and increase the content of pathogenic organisms in water. These processes will lead to a negative impact on water ecosystems, deterioration of society’s health and price rise of engineering systems and communications exploitation cost. More intense rainfalls will result in content rise of suspended solids (turbidity) owing to soil erosion with pollutions insertion from the pedosphere. It will bring the deterioration of water quality, as it will cause the growth of pathogens and other polluting matters transfer into surface and underground waters [4, 5].

It is estimated by the specialists that by 2030 the stock level of water objects might be reduced by 40% during the summer period in the most vulnerable regions of the planet. [1]

Therefore, optimization of the ecological situation (not only in Ukraine) is possible only in case of developing the approaches and principles of regulation the environmental safety which will be followed by all the countries. Design of new scientific methodological control and estimation principles of ecological safety condition level of natural systems development is one of such important approaches. If one takes the development of water ecosystems into consideration, then it is necessary to recognize the recommendations of Global Water Partnership international committee (2003), where water resource management should [6] take not only organizational and methodical questions into account, but the studies results of interaction between natural and social-economical systems as well. The design of nature conservation measures is carried out on the basis of studying the interaction inside the system of «hydroecosystem – ground ecosystems». Unfortunately, this concept does not have any concrete approaches of its realization.

The number of precipitations, temperature and evaporability which depends on humidity, speed of wind flow, temperature and radiation balance of Earth are the dominant climatic factors of impact on quantitative and qualitative indices of water ecosystems.

Considering all the mentioned above, the aim of our researches is the study of structural-functional changes of the Ukrainian Polesye water ecosystems as the result of climatic changes.

This work will analyze the questions connected with the estimation of quantitative and qualitative indices of quality of the Ukrainian Polesye rivers water basins, using the Teteriv and Ros rivers, flowing within Zhytomyr and Kyiv oblasts, as the examples. Looking into the cause-and-effect factors of changing the water ecosystems development and operation in the conditions of permanent medium technogenic load and advanced agriculture-based industry became the fundamental factor of such researches.

Determination changes regularities of ecosystem structural-functional properties and climatic characteristics together with identification of self-regulating function level (ability to maintain the stability of parameters) define this approach.

In order to achieve the goals set it was necessary to solve the following tasks:

  • processing and analysis of ecological monitoring data which characterize qualitatively and quantitatively the condition of water ecosystems and climatic constituents;
  • defining the indices which will become the basis for defining the structural-functional changes characteristics;
  • calculation of water ecosystems self-cleaning coefficient, technology intensive index and ecological index;
  • to work out corresponding regularities of qualitative characteristics and climatic parameters changes.

In order to define scientific regularities of the Teteriv and Ros rivers water systems homeostasis mechanism preservation in conditions of climate change, ecological monitoring data of Central geophysical observatory (hydrologic annuals) were systemized and processed. The data for a long-term period, 45 indicators of hydrochemical characteristics in each case, annual flow amount indices, amount of precipitations, temperature and evaporability were used.

During the data systematization and processing, normative methods [7,8]  were used, as well as defining of technology intensive, intensity processes inside the reservoir, self-cleaning ability of the water ecosystem, technology intensive index, ecological index, etc. This work shows the data about calculation gauges located along the Teteriv and Ros rivers. Changes dynamics of the rivers pollution level (average indices by periods) and structural-functional properties is almost ongoing and, therefore, this work analyzes the data for the last 10-year period.

In order to fulfill the set tasks, it was reasonable to conduct preliminary reconnaissance researches of the ecological basin condition of the researched rivers.

The Teteriv River is the Dnieper right inflow (it goes into the Kyiv Reservoir at the village of Sukholuchye which is 85 km north to Kyiv). Its length is 385 km. The river is unnavigable. The main flows are: Hnylopyat, Huyva, Zdvizh – to the right; Irsha – to the left [9].

The Ros River is the Dnieper right inflow (it goes into the Kremenchuk Reservoir close to the village of Khreschatyk). Its length is 346 km, basin square is 12 575 km². The main inflows are: the Orikhova river – to the right; the Roska river – to the left [9].

Considering the action intensities of technogenic factors and the fact that these river systems are located in different natural condition, we have noted some peculiarities of their development.

Average ecological condition index of the Ros river basin is equal to 2.3 mз which means that the basin ecosystem is out-of-balance. Ecological index of water during the period of winter mean water was high and made up 1.75. On other stages of hydrological regime the quality of water was within the I class, but during the spring tide the increase of BOD5 occurs; during the summer mean water phosphates increase occurs. According to the water acceptability appraisals for household, the content of organic matters, chrome ions and minor bacterial pollution became the limiting criteria.

In general, most small rivers of the Ros river basin are polluted by mineral oils and nitrogen compounds. In some places MPC exceeds in quantity indices, COD with some heavy metals (copper, zinc, nickel). Growing crops does not meet the demands as the result of which organic and mineral fertilizers, pesticides and fertile topsoil are washed off the fields into hydrographical network. Average agricultural usage of soils is 71%, while the amount of forests is only 11%.

Significant volumes of wastewaters discharges and the wash-out from the urbanized territories in combination with decrease of rivers water content and, hence, their abilities of self-cleaning, lead to the reduction of basin water quality. The decrease of rivers water content is caused by both changes on the catchment area and significant water withdrawals for the household needs.

Hydrochemical condition of the Teteriv River from its source to the site on the border with Kyiv oblast is slightly worsening by all indications. Rapid growth of biogenic elements of salt ammonium from 0,68 mg/dm³ (on the site above the city of Chudniv) to 1,94 mg/dm³, phosphates from 0,11 mg/dm³ to 0,34 mg/dm³ is observed. Water mineralization of the Teteriv River (within the borders of Zhytomyr) on average over the long term period is the following: 316 mg/dm³ in spring tide; 459 mg/dm³ in summer-autumn mean water; 522 mg/dm³ in winter mean water. The content of oxygen dissolved in water was satisfactory within 15,70 – 16,70 mgО2/dm3 (at the rate of 4,0 mgО2/dm3).

In comparison with the previous years, one can trace a slight worsening of the following indices: COD – 3,20-3,30 compared 3,00 mgО2/dm3 and BOD5 – 2,60-4,00 compared to 3,30 mgО2/dm3. There are no significant changes in other indices; general condition of the river remains stable.

Estimation of the Teteriv River water quality according to the salt composition shows that minimal indices of river water conform to the I class quality by the pollution criteria and they are transitional from the I class to the II class by the worst values.

Minimal values of the ecological index (Ie) were within the limits of 2,8 and 3,5. Average values of this index over the whole period of research ranged from 3,1 to 3,3. It characterizes the water as rather clean. At this, values of separate indices in water samples above and below the city of Zhytomyr were: I1 = 1,8 and 2,0, I2 = 3,1 and 4,2, I3 = 3,6 and 3,9 correspondingly.

Literature:

  1. Climate change and water resourse, Edited by Brison Bate, Zbignev Kundzevichh, Sao Khon, Janna Palutikoff, Published by IPCC, 2008. – 211 pp.
  2. Melnyk Y.S. Stability of water resources quality in Eastern Ukraine during the climate change Y.S. Melnyk, V.V. Pidlisiniuk, T.F. Kozlovska // Scientific journal “Transactions of Kremenchuk Mykhaylo Ostrohradskyi National University”. – Ed. 2/2011(67). –P.1. – p. 127-130.
  3. Report on condition of world health protection // World health Organization, 2010. Access mode: http://www.who.int/whr/2010/whr10_ru.pdf?ua=1
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  5. Zhukova O.G. Climate changes impact on surface waters ecological state/ O.G. Zhukova, L.O. Vasylenko, Y.O. Bereznytska// VI All-Ukrainian Congress of ecologists with international participation (Ecology-2017), Vinnytsia, September 20-22, 2017: scientific works anthology. – Vinnytsia: VNTU, 2017. – p. 57.
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  9. Vyshnevskyi V.I. Hydrological characteristics of rivers of Ukraine / V.I. Vyshnevskyi, O.O. Kosovets. – К., 2003. – 324 pp.
  10. The Water Code of Ukraine. News of the Verkhovna Rada of Ukraine (NVR), 1995, № 24, article.189 [Electronic resource]. Access mode : http://zakon4.rada.gov.ua/laws/show/213/95-%D0%B2%D1%80.