Zooplankton Composition in the Southwestern Sea of Marmara During the Summer Season

Year 2025, Volume: 8 Issue: 1, 97 - 102, 14.07.2025

Dalida Bedikoğlu , Sandra Jerinić , Nazli Demirel

https://doi.org/10.46384/jmsf.1719494

Abstract

The Sea of Marmara (SoM) is a highly sensitive semi-enclosed marine ecosystem that has been undergoing considerable ecological changes in the recent decades. This study aimed to evaluate the summer zooplankton community structure via vertical hauls at 0-20 m depth in Erdek Bay, located in the southwestern part of the SoM, during two consecutive years, 2019 and 2020. The results revealed marked year-to-year shifts. In 2020, total zooplankton abundance declined markedly compared to 2019, primarily due to a sharp decrease in the abundance of Penilia avirostris, which was dominant in the community during 2019. Despite the higher abundance observed in 2019, diversity indices were lower, indicating that the community structure was largely shaped by the dominance of a single species. In contrast, unlike the Cladocera group, Copepoda abundance increased in 2020 compared to 2019. As the most recent data for this region date back to the early 2010s, this research provides an updated contribution to the understanding of summer zooplankton composition in Erdek Bay. The findings highlight the necessity for long-term zooplankton monitoring with high temporal resolution to better understand zooplankton dynamics in response to environmental changes in the southwestern part of the Sea of Marmara.

Keywords

Mesozooplankton , diversity indices , abundance , Erdek Bay

Marmara Denizi’nin Güneybatısında Yaz Dönemi Zooplankton Kompozisyonu

Abstract

Marmara Denizi, son yıllarda önemli ekolojik değişimlerin yaşandığı, oldukça hassas yarı kapalı bir denizel ekosistemdir. Bu çalışma, Marmara Denizi’nin güneybatısında yer alan Erdek Körfezi'nde yaz dönemi zooplankton topluluk yapısını, iki farklı yıl olan 2019 ve 2020’de 0-20 m derinlikte yapılan dikey çekimler ile değerlendirmeyi amaçlamıştır. Elde edilen sonuçlar yıllar arası belirgin farklılıkları ortaya koymuştur. 2020 yılında, zooplanktonun toplam bolluğu 2019 yılına kıyasla önemli ölçüde azalmıştır. Bu düşüşün başlıca nedeni, 2019 yılında toplulukta baskın olan Penilia avirostris türünün bolluğundaki keskin azalmadır. 2019 yılında yüksek bolluk gözlemlenmesine rağmen, çeşitlilik indekslerinin daha düşük olması, topluluk yapısının büyük ölçüde tek bir türün baskınlığıyla şekillendiğini göstermektedir. Buna karşılık, Cladocera grubunun aksine, Copepoda bolluğu 2020 yılında 2019’a göre artış göstermiştir. Bölgeye ait en güncel veriler 2010’lu yılların başına dayandığından, bu çalışma Erdek Körfezi'ndeki yaz dönemi zooplankton bileşimine ilişkin güncel bir katkı sunmaktadır. Elde edilen bulgular, Marmara Denizi’nin güneybatı kesiminde çevresel değişimlere bağlı olarak zooplankton dinamiklerini daha iyi anlayabilmek için yüksek zaman çözünürlüğüne sahip uzun dönemli zooplankton izleme çalışmalarının gerekliliğini vurgulamaktadır.

Keywords

Mesozooplankton , çeşitlilik indeksleri , bolluk , Erdek Körfezi

References

• Alden III, R. W., Dahiya, R. C., & Young Jr, R. J. (1982). A method for the enumeration of zooplankton subsamples. Journal of Experimental Marine Biology and Ecology, 59(2-3), 185-206
• Altuğ G, Aktan Y, Oral M, Topaloğlu B, Dede A, Keskin Ç, et al. (2011). Biodiversity of the northern Aegean Sea and southern part of the Sea of Marmara, Turkey. Marine Biodiversity Records. 2011;4:e65 . https://doi.org/10.1017/S1755267211000662
• Alıçlı, B. T., Balkıs, N., & Balcı, M. (2014). Seasonal distribution of zooplankton in the gulf of Erdek (the Marmara Sea) and the impact of ecologial variables. Fresenius Environmental Bulletin, 23, 3013-3021.
• APHA (American Public Health Association). (2012). Standard Methods for the Examination of Water and Wastewater (24th ed.). Method 4500-O.C. – Dissolved Oxygen (Winkler Method), pp. 4-114 to 4-117. American Public Health Association, American Water Works Association, Water Environment Federation.
• Bedikoğlu, D., Yılmaz, I. N., Demirel, N. (2022). Reproductive strategies and population characteristics of key Cladocera species in the Sea of Marmara. Regional Studies in Marine Science, 54, 102450. https://doi.org/10.1016/j.rsma.2021.102450
• Büyükateş, Y., İnanmaz, Ö.E., (2009). Cladocerans of an urbanized harbour: effects of environmental parameters on vertical distribution, occurrence, abundance, and seasonal variation, Crustaceana, 82, 543-554. https://doi.org/10.1163/156854009X407669
• Clark, M. J. R. (1992). Enhancement to the Pielou Method for estimating the diversity of aquatic Communities. Environmental Toxicology and Chemistry, 1, 1559–1565. doi.org/10.1002/etc.5620111106
• Cushing, D. H. (1990). Plankton production and year-class strength in fish populations: An update of the match/mismatch hypothesis. Advances in Marine Biology, 26, (1), 249-293. https://doi.org/10.1016/S0065-2881(08)60202-3
• Daban, İ.B., Ayaz, O., İşmen, A. (2024). Changes on the temporal patterns of ichthyoplankton assemblages in the Çanakkale Strait, Türkiye. COMU Journal of Marine Sciences and Fisheries, 7(2):183-194. https://doi.org/10.46384/jmsf.1581960
• İşinibilir Okyar, M., Üstün, F., Orun, D.A. (2015): Changes in abundance and community structure of the zooplankton population during the 2008 mucilage event in the northeastern Marmara Sea. Turkish Journal of Zoology, 39, 28-38. https://doi.org/ 10.3906/zoo-1308-11
• İşinibilir, M. (2010) Spatial and temporal variation of zooplankton in two Bays in the Southern Sea of Marmara. Crustaceana, 83 (2), 233-244. https://doi.org/10.1163/0011211609X12512848343568
• İşinibilir, M., Kideys, A.E., Tarkan, A.N., Yılmaz, I.N. (2008). Annual cycle of zooplankton abundance and species composition in Izmit Bay (the northeastern Marmara Sea). Estuarine, Coastal and Shelf Science, 78, 739-747. https://doi.org/10.1016/j.ecss.2008.02.013
• Parsons, T. R., Maita, Y., & Lalli, C. M. (1984). A manual of chemical and biological methods for seawater analysis. Pergamon Press.
• Shiganova, T., (2005), Changes in Appendicularian Oikopleur dioica abundance caused by invasion of alien ctenophores in the Black Sea, Journal of the Marine Biological Association of the UK, 85, 477-494. doi.org/10.1017/S0025315405011410
• Steinberg, D. K., & Landry, M. R. (2017). Zooplankton and the ocean carbon cycle. Annual review of marine science, 9(1), 413-444. https://doi.org/10.1146/annurev-marine-010814-015924
• Svetlichny, L. S., Kideys, A. E., Hubareva, E. S., Besiktepe, S., Isinibilir, M. (2006). Development and lipid storage in Calanus euxinus from the Black and Marmara seas: Variabilities due to habitat conditions. Journal of Marine Systems, 59 (1–2), 52–62. doi.org/10.1016/j.jmarsys.2005.09.003
• Toklu Alıçlı, B. Balkıs, N., Balcı, M. (2014). Seasonal distribution of zooplankton in the Gulf of Erdek (the Marmara Sea) and the impact of ecological variables. Fresenius Environmental Bulletin, 23(12): 3013-3021.
• Yılmaz, İ.N. (2002): Kuzeydoğu Marmara Denizi ve Güneybatı Karadeniz üst tabaka zooplanktonunun zamana bağlı değişimi ve çevresel şartlar ile ilişkisi. (MSc. Thesis), İstanbul University, İstanbul, Türkiye.
• Yılmaz, I.N. (2015): Collapse of zooplankton stocks during Liriope tetraphylla (Hydromedusa) blooms and dense mucilaginous aggregations in a thermohaline stratified basin. Marine Ecology, 36(3), 595-610. https://doi.org/10.1111/maec.12166
• Yılmaz, I.N., İşinibilir Okyar, M., (2016). Zooplankton of the sea of Marmara. In Özsoy, E., Çağatay, M.N., Balkıs, N., Balkıs, N., Öztürk, B. (Eds.), The Sea of Marmara – Marine Biodiversity, Fisheries, Conservation and Governance (pp. 376-389): Turkish Marine Research Foundation Press.