Araştırma Makalesi
BibTex RIS Kaynak Göster

The evaluation of ecological status in Tunca (Tundzha) River (Turkish Thrace) based on environmental conditions and bacterial features

Yıl 2020, , 98 - 109, 01.04.2020

Pınar Altınoluk Mimiroğlu , Belgin Elipek , Halide Aydoğdu

https://doi.org/10.3153/AR20009

Öz

It is inevitable that the running waters which are used for a lot of different activities like fishing, irrigation, domestic water usage are under threat because of the settlements, industrial or agricultural activities. To provide the sustainable usage of these ecosystems we have to know their current features and their balance under changing environmental conditions. In the present study, the ecological status of Tunca (Tundzha) River which is located on Turkish Thrace was evaluated based on environmental conditions and bacterial features of the river. For this aim, the research has been carried out at 5 different stations in the river between October 2010 and September 2011 at monthly intervals. Some environmental conditions (temperature, dissolved oxygen, pH, conductivity, salinity, chloride, turbidity, hydrogen sulfide, magnesium, calcium, total hardness, NO3-N, NO2-N, sulfate, orthophosphate, suspended solid substances, biological oxygen demand) and bacterial features (total coliform, fecal coliform, and Escherichia coli bacterial abundances) were examined performing at the same time samplings. Consequently, it was determined that the water quality of Tunca River has proper physicochemical conditions allowing surviving of living things, but bacteriological findings belonging to the river was not found proper for direct use of water by human. Also, the correlations were evaluated between the obtained environmental features and the bacteria by using Spearman’s index. While positive correlations were found between TMAB density and some environmental parameters (water-air temperature, EC, magnesium, nitrate nitrogen, sulfate, o-phosphate, and suspended solids); negative correlations were found between TMAB density and the other parameters (pH, hydrogen sulfide, calcium, total hardness, and BOD5).

Anahtar Kelimeler

Tunca River Water quality Coliform bacteria Environmental condition Physicochemical features

Destekleyen Kurum

Trakya University Research Fund

Proje Numarası

TUBAP-2011/15

Kaynakça

  • Agbogu, V.N., Umoh, V.J., Okuofu, C.A., Smith, S.I., Ameh, J.B. (2006). Study of the bacteriological and physico-chemical ındicators of pollution of surface waters in Zaria, Nigeria. African Journal of Biotechnology, 5(9), 732-737.
  • Alves, R.I., Machado, C.S., Beda, C.F., Fregonesi, B.M., Nadal, M., Sierra, J., Domingo, J.L., Segura-Muñoz, S.I. (2018). Water quality assessment of the Pardo River Basin, Brazil: a multivariate approach using limnological parameters, metal concentrations and indicator bacteria. Archives of Environmental Contamination and Toxicology, 75(2), 199-212. https://doi.org/10.1007/s00244-017-0493-7
  • Anonymous (2016). Surface water quality control regulation. Official Gazette No: 29797 of 10 August 2016, Ankara.
  • Aytas, S., Erenturk, S., Aslani, M.A.A., Yusan, S., Turkozu, D.A. Gok, C., Karali, T., Gokce, M., Oguz, K.F. (2014). Determination and evaluation of natural radioactivity and heavy metal levels in the aquatic environment of trans-boundary rivers: Maritza, Tundja and Arda. Journal of Radioanalytical and Nuclear Chemistry, 300, 933-945. https://doi.org/10.1007/s10967-014-3091-4
  • Bernot, M.J., Dodds, W.K. (2005). Nitrogen retention, removal, and saturation in lotic ecosystems. Ecosystems, 8, 442-453. https://doi.org/10.1007/s10021-003-0143-y
  • Bulut, C., Akçimen, U., Uysal, K., Küçükkara, R., Savaşer, S. (2010). Seasonal variations of physicochemical and microbiological parameters of the Karanfilli Cay creek water and ıts aquacultural evaluation. Dumlupınar University Journal of Natural Sciences, 21, 1-7.
  • Bulut, C., Kubilay, A., Akçimen, U., Yener, O. (2016). Seasonal changes of microbiology quality in Egirdir Lake. Süleyman Demirel University Journal of Natural and Applied Sciences, 20(1), 50-53.
  • Camur-Elipek, B., Arslan, N., Kirgiz, T., Oterler, B. (2006). Benthic macrofauna in Tunca River (Turkey) and their relationships with environmental variables. Acta Hydrochimica Hydrobiologica, 34(4), 360-366. https://doi.org/10.1002/aheh.200500631
  • Çolakoğlu, F., Çakır, F. (2004). Microbiological quality of Sarıcay. Turkish Journal of Aquatic Life, 2(3), 320-327.
  • Egemen, O., Sunlu, U. (1999). Water quality. Ege University Fisheries Faculty Issue number: 14, İzmir. 148pp. ISBN: 975-483-141-6.
  • Elmacı, A., Teksoy, A., Topaç, F.O., Özengin, N., Başkaya, H.S. (2008). Monitoring of seasonal variation of microbial quality in Lake Ulubat. Uludag University Journal of The Faculty of Engineering and Architecture, 13(1), 93-103.
  • Erçal, E. (2007). The observing of the heavy metal pollution in the gulfs of the Northern Cyprus Güzelyurt, Girne and Mağusa. Marmara University, Institute of Natural Sciences, Master Thesis. 82pp.
  • Georgieva, N., Yaneva, Z., Dospatliev, L. (2010). Analyses of natural water quality in Stara Zagora region according to the parameters sulfates and chlorides. Trakia Journal of Sciences, 8(2), 517-524.
  • Halkman, K. (2005). Merck food microbiology applications. Basak Printhouse Ltd. Sti., Ankara. 358pp. ISBN 975-00373-0-8
  • Hunt, A.O., Sarıhan, E. (2004). Physico-chemical and bacteriological features on Sarıçam stream which is a branch of the Seyhan River. Journal of Egirdir Fisheries Faculty, 12(2), 51-58.
  • Islam, M.M., Hofstra, N., Islam, M.A. (2017). The impact of environmental variables on fecalindicator bacteria in the Betna river basin, Bangladesh. Environmental Processes, 4(2), 319-332. https://doi.org/10.1007/s40710-017-0239-6
  • Jamieson, R.C., Gordon, R.J., Tattrie, S.C., Stratton, G.W. (2003). Sources and persistence of fecal coliform bacteria in a rural watershed. Water Quality Research Journal of Canada, 38(1), 33-47. https://doi.org/10.2166/wqrj.2003.004
  • Janeva, I.J., Russev, B.K. (1985). Trends in changes of the hydrobiological and saprobiological state of the Tundzha River. II. May-November 1981. Hydrobiology (Sofia), 26, 15-36.
  • Karafistan, A., Colakoglu-Arik, F. (2005). Physical, chemical and microbiological water quality of the Manyas Lake, Turkey. Mitigation and Adaptation Strategies for Global Change, 10, 127-143. https://doi.org/10.1007/s11027-005-7835-x
  • Kavaz, E. (1997). Benthic macroinvertebrate fauna of Tunca River. Trakya University, Institute of Natural Sciences, Master Thesis. 38pp.
  • Kirgiz, T., Camur, B., Arslan, N. (2005). Preliminary study of Enchytraeidae (Oligochatea) in Tunca River. Proceedings of the Estonian Academy of Sciences: Biology/Ecology, 54(4), 310-314.
  • Koloren, Z., Taş, B., Kaya, D. (2011). Microbiological pollution of Gaga Lake in Ordu (Turkey), The Black Sea Journal of Sciences, 2(1), 74-85.
  • Krebs, J.C. (1999). Ecological methodology. Addison Wesley Longman, Inc., Menlo Park, California. ISBN: 0321021738/9780321021731
  • Kumar, A., Bisht, B.S., Joshi, V.D., Singh, A.K., Talwar, A. (2010). Physical, chemical and bacteriological study of water from rivers of Uttarakhand. Journal of Human Ecology, 32(3), 169-173. https://doi.org/10.1080/09709274.2010.11906336
  • Loucif, K., Neffar, S., Menasria, T., Maazi, M. C., Houhamdi, M., Chenchouni, H. (2020). Physico-chemical and bacteriological quality assessment of surface water at Lake Tonga in Algeria. Environmental Nanotechnology, Monitoring & Management, 13, 100284. https://doi.org/10.1016/j.enmm.2020.100284
  • Mishra, A., Bhatt, V. (2008). Physico-chemical and microbiological analysis of under ground water in V.V Nagar and near by places of Anand District, Gujarat, India. E-Journal of Chemistry, 5(3), 487-492. https://doi.org/10.1155/2008/671978
  • Mishra, A., Bhatt, V.D., Sevak, N., Shah, P., Patel, K., Patel, C. (2010). Comparative study of physico-chemical and microbial parameters on lotic and ground-waters in selected outlying areas of central Gujarat. Journal of Chemical and Pharmaceutical Research, 2(4), 174-177.
  • Mishra, A., Mukherjee, A., Tripathi, B.D. (2009). Seasonal and temporal variations in physicochemical and bacteriological characteristics of River Ganga in Varanasi. International Journal of Environmental Research, 3(3), 395-402.
  • Nguyen, H.T.M., Le, Q.T.P., Garnier, J., Janeau, J. L., Rochelle-Newall, E. (2016). Seasonal variability of fecalindicator bacteria numbers and die-off rates in the Red River basin, North Vietnam. Scientific Reports, 6, 21644. https://doi.org/10.1038/srep21644
  • Niemi, J., Raateland, A. (2007). River water quality in the Finnish Eurowaternet. Boreal Environment Research, 12, 571-584.
  • Öterler, B. (2003). An investigation on Tundza River phytoplancton and their relationships with water quality. Trakya University, Institute of Natural Sciences, Master Thesis. 68pp.
  • Russev, B.K., Nikolova, M.I., Dimitrova, M.A. (1984). Hydrobiological and saprobiological alterations in The Tundzha River. I. 1995-1967. Hydrobiology (Sofia), 22, 59-73.
  • Sabae, Z.S., Rabeh, A.S. (2007). Evaluation of the microbial quality of the River Nile waters at Damietta Branch, Egypt. Egyptian Journal of Aquatıc Research, 33(1), 301-311.
  • Saha, M.L., Khan, M.R., Ali, M., Hoque, S. (2009). Bacterial load and chemical pollution level of the River Buriganga. Bangladesh Journal of Botany, 38(1), 87-91. https://doi.org/10.3329/bjb.v38i1.5128
  • Sakcali, M. S., Yilmaz, R., Gucel, S., Yarci, C., Ozturk, M. (2009). Water pollution studies in the Rivers of Edirne Region. Aquatic Ecosystem Health & Management, 12(3), 313-319. https://doi.org/10.1080/14634980903133757
  • Suneela, M., Krishna, G.R., Krishna, K.V., Sai, V.M., Bhargav, V., Reddy, K.S., Srinivas, D.S.S., Srinivas, J.S. (2008). Water and sediment analysis of Hussain Sagar Lake, Hyderabad, Proceeding of Taal 2007. The 12th World Lake Conference, 304-306.
  • Toroğlu, E., Toroğlu, S. (2009). Microbial pollution of water in Golbasi Lake in Adiyaman Turkey. Journal of Environmental Biology, 30(1), 33-38.
  • Toroğlu, E., Toroğlu, S., Alaeddinoğlu, F. (2006). Water pollution in the Aksu River (Kahraman Maras). Turkish Journal of Geographical Sciences, 4(1), 93-103.
  • Uluçam, G. (1997). Investigate a proper purification method for domestic and ındustrial wastes in Tunca River (in Turkish with English Abstract). Trakya University, Institute of Natural Sciences, Master Thesis. 153pp.
  • Uzunov, J.I. (1980). Water Oligochets (Oligochaeta, Limicola) from some Bulgarian rivers. Frequency and Domination, Hydrobiology, 12, 79-89.
  • Uzunov, Y., Kapustina, L. (1993). Current review on Oligochaeta from macrozoobenthic communities of the Bulgarian rivers. Lauterbornia, 13, 73-83.
  • Vassilev, M., Apostolou, A., Velkov, B., İvanova, P., Panayotova, M., Dobrev, D., Pehlivanov, L. (2010). Status of Gobiid ichtyofauna (Gobiidae) in Bulgaria: Taxonomical, conservative, ecological and social aspects. Natura Montenegrina, Podgorica, 10(2), 115-124.
  • Venkatesharaju, K., Ravikumar, P., Somashekar, R.K., Prakash, K.L. (2010). Physico-chemical and bacteriological investigation on the River Cauvery of Kollegal Stretch in Karnataka. Kathmandu University Journal of Science, Engineering and Technology, 6(1), 50-59. https://doi.org/10.3126/kuset.v6i1.3310

Yıl 2020, , 98 - 109, 01.04.2020

Pınar Altınoluk Mimiroğlu , Belgin Elipek , Halide Aydoğdu

https://doi.org/10.3153/AR20009

Öz

Proje Numarası

TUBAP-2011/15

Kaynakça

  • Agbogu, V.N., Umoh, V.J., Okuofu, C.A., Smith, S.I., Ameh, J.B. (2006). Study of the bacteriological and physico-chemical ındicators of pollution of surface waters in Zaria, Nigeria. African Journal of Biotechnology, 5(9), 732-737.
  • Alves, R.I., Machado, C.S., Beda, C.F., Fregonesi, B.M., Nadal, M., Sierra, J., Domingo, J.L., Segura-Muñoz, S.I. (2018). Water quality assessment of the Pardo River Basin, Brazil: a multivariate approach using limnological parameters, metal concentrations and indicator bacteria. Archives of Environmental Contamination and Toxicology, 75(2), 199-212. https://doi.org/10.1007/s00244-017-0493-7
  • Anonymous (2016). Surface water quality control regulation. Official Gazette No: 29797 of 10 August 2016, Ankara.
  • Aytas, S., Erenturk, S., Aslani, M.A.A., Yusan, S., Turkozu, D.A. Gok, C., Karali, T., Gokce, M., Oguz, K.F. (2014). Determination and evaluation of natural radioactivity and heavy metal levels in the aquatic environment of trans-boundary rivers: Maritza, Tundja and Arda. Journal of Radioanalytical and Nuclear Chemistry, 300, 933-945. https://doi.org/10.1007/s10967-014-3091-4
  • Bernot, M.J., Dodds, W.K. (2005). Nitrogen retention, removal, and saturation in lotic ecosystems. Ecosystems, 8, 442-453. https://doi.org/10.1007/s10021-003-0143-y
  • Bulut, C., Akçimen, U., Uysal, K., Küçükkara, R., Savaşer, S. (2010). Seasonal variations of physicochemical and microbiological parameters of the Karanfilli Cay creek water and ıts aquacultural evaluation. Dumlupınar University Journal of Natural Sciences, 21, 1-7.
  • Bulut, C., Kubilay, A., Akçimen, U., Yener, O. (2016). Seasonal changes of microbiology quality in Egirdir Lake. Süleyman Demirel University Journal of Natural and Applied Sciences, 20(1), 50-53.
  • Camur-Elipek, B., Arslan, N., Kirgiz, T., Oterler, B. (2006). Benthic macrofauna in Tunca River (Turkey) and their relationships with environmental variables. Acta Hydrochimica Hydrobiologica, 34(4), 360-366. https://doi.org/10.1002/aheh.200500631
  • Çolakoğlu, F., Çakır, F. (2004). Microbiological quality of Sarıcay. Turkish Journal of Aquatic Life, 2(3), 320-327.
  • Egemen, O., Sunlu, U. (1999). Water quality. Ege University Fisheries Faculty Issue number: 14, İzmir. 148pp. ISBN: 975-483-141-6.
  • Elmacı, A., Teksoy, A., Topaç, F.O., Özengin, N., Başkaya, H.S. (2008). Monitoring of seasonal variation of microbial quality in Lake Ulubat. Uludag University Journal of The Faculty of Engineering and Architecture, 13(1), 93-103.
  • Erçal, E. (2007). The observing of the heavy metal pollution in the gulfs of the Northern Cyprus Güzelyurt, Girne and Mağusa. Marmara University, Institute of Natural Sciences, Master Thesis. 82pp.
  • Georgieva, N., Yaneva, Z., Dospatliev, L. (2010). Analyses of natural water quality in Stara Zagora region according to the parameters sulfates and chlorides. Trakia Journal of Sciences, 8(2), 517-524.
  • Halkman, K. (2005). Merck food microbiology applications. Basak Printhouse Ltd. Sti., Ankara. 358pp. ISBN 975-00373-0-8
  • Hunt, A.O., Sarıhan, E. (2004). Physico-chemical and bacteriological features on Sarıçam stream which is a branch of the Seyhan River. Journal of Egirdir Fisheries Faculty, 12(2), 51-58.
  • Islam, M.M., Hofstra, N., Islam, M.A. (2017). The impact of environmental variables on fecalindicator bacteria in the Betna river basin, Bangladesh. Environmental Processes, 4(2), 319-332. https://doi.org/10.1007/s40710-017-0239-6
  • Jamieson, R.C., Gordon, R.J., Tattrie, S.C., Stratton, G.W. (2003). Sources and persistence of fecal coliform bacteria in a rural watershed. Water Quality Research Journal of Canada, 38(1), 33-47. https://doi.org/10.2166/wqrj.2003.004
  • Janeva, I.J., Russev, B.K. (1985). Trends in changes of the hydrobiological and saprobiological state of the Tundzha River. II. May-November 1981. Hydrobiology (Sofia), 26, 15-36.
  • Karafistan, A., Colakoglu-Arik, F. (2005). Physical, chemical and microbiological water quality of the Manyas Lake, Turkey. Mitigation and Adaptation Strategies for Global Change, 10, 127-143. https://doi.org/10.1007/s11027-005-7835-x
  • Kavaz, E. (1997). Benthic macroinvertebrate fauna of Tunca River. Trakya University, Institute of Natural Sciences, Master Thesis. 38pp.
  • Kirgiz, T., Camur, B., Arslan, N. (2005). Preliminary study of Enchytraeidae (Oligochatea) in Tunca River. Proceedings of the Estonian Academy of Sciences: Biology/Ecology, 54(4), 310-314.
  • Koloren, Z., Taş, B., Kaya, D. (2011). Microbiological pollution of Gaga Lake in Ordu (Turkey), The Black Sea Journal of Sciences, 2(1), 74-85.
  • Krebs, J.C. (1999). Ecological methodology. Addison Wesley Longman, Inc., Menlo Park, California. ISBN: 0321021738/9780321021731
  • Kumar, A., Bisht, B.S., Joshi, V.D., Singh, A.K., Talwar, A. (2010). Physical, chemical and bacteriological study of water from rivers of Uttarakhand. Journal of Human Ecology, 32(3), 169-173. https://doi.org/10.1080/09709274.2010.11906336
  • Loucif, K., Neffar, S., Menasria, T., Maazi, M. C., Houhamdi, M., Chenchouni, H. (2020). Physico-chemical and bacteriological quality assessment of surface water at Lake Tonga in Algeria. Environmental Nanotechnology, Monitoring & Management, 13, 100284. https://doi.org/10.1016/j.enmm.2020.100284
  • Mishra, A., Bhatt, V. (2008). Physico-chemical and microbiological analysis of under ground water in V.V Nagar and near by places of Anand District, Gujarat, India. E-Journal of Chemistry, 5(3), 487-492. https://doi.org/10.1155/2008/671978
  • Mishra, A., Bhatt, V.D., Sevak, N., Shah, P., Patel, K., Patel, C. (2010). Comparative study of physico-chemical and microbial parameters on lotic and ground-waters in selected outlying areas of central Gujarat. Journal of Chemical and Pharmaceutical Research, 2(4), 174-177.
  • Mishra, A., Mukherjee, A., Tripathi, B.D. (2009). Seasonal and temporal variations in physicochemical and bacteriological characteristics of River Ganga in Varanasi. International Journal of Environmental Research, 3(3), 395-402.
  • Nguyen, H.T.M., Le, Q.T.P., Garnier, J., Janeau, J. L., Rochelle-Newall, E. (2016). Seasonal variability of fecalindicator bacteria numbers and die-off rates in the Red River basin, North Vietnam. Scientific Reports, 6, 21644. https://doi.org/10.1038/srep21644
  • Niemi, J., Raateland, A. (2007). River water quality in the Finnish Eurowaternet. Boreal Environment Research, 12, 571-584.
  • Öterler, B. (2003). An investigation on Tundza River phytoplancton and their relationships with water quality. Trakya University, Institute of Natural Sciences, Master Thesis. 68pp.
  • Russev, B.K., Nikolova, M.I., Dimitrova, M.A. (1984). Hydrobiological and saprobiological alterations in The Tundzha River. I. 1995-1967. Hydrobiology (Sofia), 22, 59-73.
  • Sabae, Z.S., Rabeh, A.S. (2007). Evaluation of the microbial quality of the River Nile waters at Damietta Branch, Egypt. Egyptian Journal of Aquatıc Research, 33(1), 301-311.
  • Saha, M.L., Khan, M.R., Ali, M., Hoque, S. (2009). Bacterial load and chemical pollution level of the River Buriganga. Bangladesh Journal of Botany, 38(1), 87-91. https://doi.org/10.3329/bjb.v38i1.5128
  • Sakcali, M. S., Yilmaz, R., Gucel, S., Yarci, C., Ozturk, M. (2009). Water pollution studies in the Rivers of Edirne Region. Aquatic Ecosystem Health & Management, 12(3), 313-319. https://doi.org/10.1080/14634980903133757
  • Suneela, M., Krishna, G.R., Krishna, K.V., Sai, V.M., Bhargav, V., Reddy, K.S., Srinivas, D.S.S., Srinivas, J.S. (2008). Water and sediment analysis of Hussain Sagar Lake, Hyderabad, Proceeding of Taal 2007. The 12th World Lake Conference, 304-306.
  • Toroğlu, E., Toroğlu, S. (2009). Microbial pollution of water in Golbasi Lake in Adiyaman Turkey. Journal of Environmental Biology, 30(1), 33-38.
  • Toroğlu, E., Toroğlu, S., Alaeddinoğlu, F. (2006). Water pollution in the Aksu River (Kahraman Maras). Turkish Journal of Geographical Sciences, 4(1), 93-103.
  • Uluçam, G. (1997). Investigate a proper purification method for domestic and ındustrial wastes in Tunca River (in Turkish with English Abstract). Trakya University, Institute of Natural Sciences, Master Thesis. 153pp.
  • Uzunov, J.I. (1980). Water Oligochets (Oligochaeta, Limicola) from some Bulgarian rivers. Frequency and Domination, Hydrobiology, 12, 79-89.
  • Uzunov, Y., Kapustina, L. (1993). Current review on Oligochaeta from macrozoobenthic communities of the Bulgarian rivers. Lauterbornia, 13, 73-83.
  • Vassilev, M., Apostolou, A., Velkov, B., İvanova, P., Panayotova, M., Dobrev, D., Pehlivanov, L. (2010). Status of Gobiid ichtyofauna (Gobiidae) in Bulgaria: Taxonomical, conservative, ecological and social aspects. Natura Montenegrina, Podgorica, 10(2), 115-124.
  • Venkatesharaju, K., Ravikumar, P., Somashekar, R.K., Prakash, K.L. (2010). Physico-chemical and bacteriological investigation on the River Cauvery of Kollegal Stretch in Karnataka. Kathmandu University Journal of Science, Engineering and Technology, 6(1), 50-59. https://doi.org/10.3126/kuset.v6i1.3310
Toplam 43 adet kaynakça vardır.

Ayrıntılar

Birincil Dil İngilizce
Konular Hidrobiyoloji
Bölüm Research Articles
Yazarlar

Pınar Altınoluk Mimiroğlu 0000-0002-8524-0972

Belgin Elipek 0000-0002-0954-8967

Halide Aydoğdu 0000-0002-1778-2200

Proje Numarası TUBAP-2011/15
Yayımlanma Tarihi 1 Nisan 2020
Gönderilme Tarihi 18 Şubat 2020
Yayımlandığı Sayı Yıl 2020

Kaynak Göster

APA Altınoluk Mimiroğlu, P., Elipek, B., & Aydoğdu, H. (2020). The evaluation of ecological status in Tunca (Tundzha) River (Turkish Thrace) based on environmental conditions and bacterial features. Aquatic Research, 3(2), 98-109. https://doi.org/10.3153/AR20009

16291

is licensed under a CreativeCommons Attribtion-ShareAlike 4.0 International Licence 14628   1325927040

Diamond Open Access refers to a scholarly publication model in which journals and platforms do not charge fees to either authors or readers.

Open Access Statement:

This is an open access journal which means that all content is freely available without charge to the user or his/her institution. Users are allowed to read, download, copy, distribute, print, search, or link to the full texts of the articles, or use them for any other lawful purpose, without asking prior permission from the publisher or the author. This is in accordance with the BOAI definition of open access.

Archiving Policy:

Archiving is done according to TÜBİTAK ULAKBİM "DergiPark" publication policy (LOCKSS).