The eastern Mediterranean basin is one of the most oligotrophic regions in the world, and has been described as a ‘marine desert’ due to its very low chlorophyll concentrations (Azov 1991, Krom et al. 1991, Antoine et al. 1995). Nutrient content, phytoplankton and zooplankton biomass, primary production and fish stocks are known to be higher in the northern Aegean Sea (Stergiou et al. 1997, Siokou-Frangou et al. 2002). Moreover, the composition of the mesozooplankton community was found to significantly differ between the northern and southern parts of the Aegean Sea (Sever 2009, Mazzocchi et al. 2014). The open marine areas of the Aegean and Levantine Seas (Siokou-Frangou et al. 2002, Aktan 2011), the two largest basins surrounding Turkey, have also been documented as oligotrophic. Although the Aegean Sea, which is one of the important basins of the Mediterranean, has an oligotrophic structure in general, it shows important biochemical differences between its north and south. Biodiversity, nutrient content and fishing activities were found to be higher in the northern Aegean Sea than in the southern Aegean Sea (Stergiou et al. 1997, Mazzocchi et al. 2014, Sever 2009). Furthermore, coastal domestic and industrial waste from major cities (such as Muğla, Antalya or Adana) as well as freshwater inputs from numerous small rivers results in local increases in biological production (Polat 2002, Kontas et al. 2004, Polat-Beken et al. 2009).
Basic knowledge of the structure of the zooplankton community and changes in species composition in different marine environments is still needed to better understand the ecological functioning of this basin. In general, although there have been various local studies on zooplankton communities, including information regarding their spatial and temporal variations along the eastern Mediterranean coastline (Benli et al. 2001, Isinibilir 2009, Isari et al. 2006, Protopapa et al. 2020, Sever 2009, Siokou-Frangou et al. 2009, Tarkan 2000, Terbıyık Kurt and Polat 2013, Toklu-Alıçlı and Sarıhan 2016, Uysal and Shmeleva 2012, Zervoudaki et al. 2006), there is limited data from large-scale investigations in open waters (Mazzocchi et al. 1997, 2007, 2014; Molinero et al. 2009; Siokou-Frangou et al. 1997).
The fact that the area in question included various coastal areas as well as open sea made it ideal for studying the regional variation of zooplankton community composition. The aim of this research is to determine the main zooplankton distribution patterns and dominant species compositions in the eastern Mediterranean, especially Turkish coastal areas, and to expand our knowledge about the pelagic ecosystem.
The study was carried out at 70 stations between 11 August and 4 September 2006 and between 10 July and 13 August 2008 in the Mediterranean Sea around the Turkish peninsula with the help of R/V YUNUS-S (Figure 1, Table 1). The northern Aegean Sea (NA) group was represented by 11 stations, the southern Aegean Sea (SA) by 19 stations, the coastal waters of the Levantine Sea (LSC) by 31 stations and the open waters of the Levantine Sea (LSO) by 9 stations. Temperature and salinity were also measured at each station with a SEABIRD CTD probe. Chlorophyll-
Mesozooplankton stations sampled in the eastern Mediterranean Sea
Stations data from the R/V YUNUS-S cruise in the eastern Mediterranean Sea
Station Number | Station Name | Region | Date | Latitude (N) | Longitude (E) | Total Depth (m) |
---|---|---|---|---|---|---|
1 | NA12 | NA | 09.07.2006 | 39°48.534 | 26°05.552 | 21 |
2 | NA14 | NA | 09.07.2006 | 39°57.309 | 26°04.095 | 18 |
3 | NA15 | NA | 14.07.2006 | 40°20.166 | 26°11.921 | 210 |
4 | NA16 | NA | 13.07.2006 | 40°28.113 | 26°25.471 | 500 |
5 | NA17 | NA | 13.07.2006 | 40°32.624 | 26°40.386 | 100 |
6 | NA18 | NA | 13.07.2006 | 40°35.344 | 26°46.041 | 66 |
7 | NA19 | NA | 13.07.2006 | 40°35.259 | 26°28.501 | 47 |
8 | NA21 | NA | 14.07.2006 | 40°15.223 | 25°54.840 | 69 |
9 | NA22 | NA | 10.07.2006 | 40°09.890 | 25°39.306 | 80 |
10 | NA23 | NA | 09.07.2006 | 40°05.774 | 25°51.762 | 33 |
11 | NA24 | NA | 14.07.2006 | 40°10.954 | 26°01.935 | 37 |
12 | SA2 | SA | 13.08.2006 | 38°08.154 | 26°33.985 | 29 |
13 | SA3 | SA | 13.08.2006 | 38°08.244 | 26°36.985 | 48 |
14 | SA4 | SA | 13.08.2006 | 37°45.866 | 27°03.787 | 175 |
15 | SA7 | SA | 14.08.2006 | 37°20.167 | 27°19.735 | 35 |
16 | SA8 | SA | 14.08.2006 | 37°23.148 | 27°25.281 | 10 |
17 | SA10 | SA | 14.08.2006 | 37°16.121 | 27°22.479 | 57 |
18 | SA11 | SA | 14.08.2006 | 37°09.935 | 27°30.949 | 40 |
19 | SA12 | SA | 14.08.2006 | 37°09.456 | 27°30.705 | 30 |
20 | SA19 | SA | 16.08.2006 | 36°59.901 | 27°43.143 | 42 |
21 | SA22 | SA | 16.08.2006 | 36°57.650 | 28°12.234 | 28 |
22 | SA25 | SA | 17.08.2006 | 36°37.123 | 28°01.498 | 30 |
23 | SA26 | SA | 17.08.2006 | 36°33.041 | 28°12.594 | 35 |
24 | SA90 | SA | 30.08.2006 | 37°15.916 | 27°36.263 | 9 |
25 | SA91 | SA | 30.08.2006 | 37°16.197 | 27°34.244 | 12 |
26 | SA92 | SA | 30.08.2006 | 37°15.045 | 27°33.695 | 16 |
27 | SA93 | SA | 30.08.2006 | 37°15.968 | 27°29.061 | 20 |
28 | SA94 | SA | 30.08.2006 | 37°14.461 | 27°22.980 | 57 |
29 | SA101 | SA | 03.09.2006 | 37°09.697 | 27°22.617 | 30 |
30 | SA102 | SA | 03.09.2006 | 37°19.104 | 27°13.245 | 49 |
31 | LSC30 | LSC | 17.08.2006 | 36°31.608 | 29°07.381 | 28 |
32 | LSC31 | LSC | 18.08.2006 | 36°15.583 | 29°24.560 | 40 |
33 | LSC32 | LSC | 18.08.2006 | 36°01.141 | 29°30.148 | 1600 |
34 | LSC33 | LSC | 18.08.2006 | 36°07.500 | 29°57.000 | 1009 |
35 | LSC37 | LSC | 19.08.2006 | 36°13.200 | 32°18.537 | 38 |
36 | LSC38 | LSC | 17.08.2006 | 36°03.573 | 32°52.445 | 15 |
37 | LSC44a | LSC | 20.08.2006 | 36°11722 | 33°45643 | 14 |
38 | LSC59 | LSC | 22.08.2006 | 36°31.350 | 36°01.456 | 10 |
39 | LSC61 | LSC | 22.08.2006 | 35°57.679 | 35°55.627 | 70 |
40 | LSC65 | LSC | 23.08.2006 | 36°31.350 | 35°25.333 | 64 |
41 | LSC67 | LSC | 24.08.2006 | 36°46.399 | 34°38.348 | 13 |
42 | LSC68 | LSC | 24.08.2006 | 36°15.175 | 33°48.802 | 24 |
43 | LSC69 | LSC | 24.08.2006 | 36°18.135 | 33°51.746 | 22 |
44 | LSC79 | LSC | 26.08.2006 | 36°37.041 | 30°36.041 | 64 |
45 | LSC81 | LSC | 26.08.2006 | 36°27.440 | 30°33.091 | 65 |
46 | LSC11 | LSC | 16.07.2008 | 33°58.390 | 35°26.400 | 1430 |
47 | LSC12 | LSC | 16.07.2008 | 33°49.593 | 35°27.400 | 500 |
48 | LSC13 | LSC | 17.07.2008 | 34°14.900 | 35°36.188 | 210 |
49 | LSC14 | LSC | 17.07.2008 | 34°01.295 | 35°35.487 | 512 |
50 | LSC15 | LSC | 19.07.2008 | 34°26.603 | 35°43.626 | 264 |
51 | LSC16 | LSC | 19.07.2008 | 35°12.823 | 35°09.197 | 1500 |
52 | LSC17 | LSC | 21.07.2008 | 35°26.729 | 35°31.128 | 1397 |
53 | LSC18 | LSC | 22.07.2008 | 35°35.023 | 35°19.122 | 1200 |
54 | LSC19 | LSC | 22.07.2008 | 35°39.582 | 34°54.051 | 1050 |
55 | LSC20 | LSC | 22.07.2008 | 35°42.463 | 34°35.265 | 160 |
56 | LSC21 | LSC | 22.07.2008 | 35°55.443 | 34°17.898 | 840 |
57 | LSC22 | LSC | 22.07.2008 | 36°09.117 | 33°58.340 | 74 |
58 | LSC23 | LSC | 23.07.2008 | 36°03.743 | 33°19.479 | 214 |
59 | LSC24 | LSC | 23.07.2008 | 35°57.718 | 32°47.352 | 65 |
60 | LSC25 | LSC | 23.07.2008 | 36°24.649 | 31°40.371 | 2000 |
61 | LSC26 | LSC | 23.07.2008 | 36°43.412 | 30°58.711 | 350 |
62 | LSO2 | LSO | 12.07.2008 | 35°40.9854 | 30°30.1947 | 1430 |
63 | LSO3 | LSO | 13.07.2008 | 35°57.133 | 30°30.396 | 1200 |
64 | LSO4 | LSO | 13.07.2008 | 35°26.2102 | 30°1.7999 | 2500 |
65 | LSO5 | LSO | 13.07.2008 | 34°56.215 | 31°17.754 | 2500 |
66 | LSO6 | LSO | 13.07.2008 | 34°22.300 | 31°49.50 | 2500 |
67 | LSO7 | LSO | 14.07.2008 | 34°17.513 | 32°35.914 | 2500 |
68 | LSO8 | LSO | 14.07.2008 | 34°08.555 | 33°25.751 | 2500 |
69 | LSO9 | LSO | 14.07.2008 | 34°03.068 | 34°12.465 | 2500 |
70 | LSO10 | LSO | 14.07.2008 | 33°58.571 | 34°58.046 | 2500 |
NA: northern Aegean Sea; SA: southern Aegean Sea; LSC: coastal waters of the Levantine Sea; LSO: open waters of the Levantine Sea
Species diversity and dominance were estimated using the Shannon–Weaver formula (Zar 1984). The differences in physical and biological data (total zooplankton abundance and biomass) between areas were evaluated with ANOVA (SPSS v. 22). Differences in the zooplankton community were evaluated for spatial variation with similarities and multidimensional scaling (MDS) analysis by calculating log (x + 1)-transformed abundance data on the basis of the Bray–Curtis similarity index. The differences between the samples were assessed by a one-way analysis of similarities (ANOSIM) permutation test. Using the similarities percentage procedure according to SIMPER was performed to determine the dominant species that contributed to the spatial differences in community structure. The MDS, ANOSIM and SIMPER procedures were performed using the software package PRIMER 6 (Clarke and Warwick, 1994).
The data were collected over two summers from the Aegean and Levantine Seas. The overall means of the environmental parameters are presented in Table 2. The among-region differences were clear for temperature (F3;69 = 137.29,
Mean values and standard deviations of environmental parameters in each sub-region of the eastern Mediterranean Sea
Sea | Region | Water temperature (°C) | Water Salinity (PSU) | Total Chlorophyll- |
---|---|---|---|---|
Aegean Sea | Northern Aegean Sea (NA) | 17.09 ± 1.37 | 37.38 ± 1.28 | 0.23 ± 0.16a |
Southern Aegean Sea (SA) | 24.50 ± 1.88 | 39.09 ± 0.18 | 0.89 ± 0.76b | |
Levantine Sea | Coastal Waters of the Levantine Sea (LSC) | 27.21 ± 1.61 | 39.36 ± 0.14 | 0.87 ± 0.69b |
Open Waters of the Levantine Sea (LSO) | 22.26 ± 0.76 | 39.15 ± 0.08 | 0.56 ± 0.40b |
Taking all sampling stations into account, the zooplankton abundance values ranged between 123 and 23,931 ind m−3, while biomass values ranged between 80 and 3200 mg m−3 (Figure 2). The highest mean abundance (4562 ind m−3) and biomass (748 mg m−3) values were detected in the southern Aegean Sea (SA), especially in Station SA90, particularly due to
Fluctuations in zooplankton abundance (ind m−3), biomass (mg m−3), number of species and dominance (D)
Generally, Copepoda was the most abundant group in the LSO area (Table 4), but the maximum abundance (11,757 ind m−3; Station SA90) was recorded in the southern Aegean Sea (Figure 3).
Fluctuations in dominant zooplankton groups in the sampling area
Species first recorded in the present study.
Species | Aegean Sea | Levantine Sea | Stations |
---|---|---|---|
*, A | TL, L | NA12, NA24 | |
*, M, A | - | NA15 | |
+, * | TL, L | SA26 | |
*, M, A | TL, L | NA12, NA15, NA16, NA17, NA18, NA19, NA21, NA24, SA10, SA101, SA102, SA11, SA12, SA2, SA3, SA4, SA7, SA22, SA26, SA94 | |
*, M, A | TL, L | SA102, SA25, SA26 | |
*, M, A | TL, L | NA19, SA4 | |
*, M, A | TL, L | NA15, NA16, NA17, NA18, NA19, NA21 | |
TA, A | #, L | LSC11, LSC12, LSC16, LSC17, LSC19, LSC20, LSC21, LSC22, LSC24, LSC25, LSC26, LSO2, LSO3, LSO4, LSO5, LSO6, LSO7, LSO8, LSO9, | |
*, A | #, L | NA16, NA22, SA4, SA25, SA102, LSC33, LSC79, LSO9 | |
+, * | #, μ | NA14, NA15, NA17, NA21, NA22, NA24, SA10, LSC11, LSC22, LSC30, LSC79, LSC81, LSO6 | |
*, M, A | TL, L | SA19, SA25, SA26 | |
*, A | TL, L | NA12, NA21, SA101 | |
*, M, A | TL, L | NA12, NA14, NA15, NA16, NA17, NA18, NA21, NA22, NA23, NA24, SA3, SA4, SA7, SA10, SA11, SA12, SA22, SA26, SA92, SA93, SA94, SA101, SA102 | |
+, * | #, L | LSC12, LSC14, LSC16, LSC17, LSC18, LSC19, LSC20, LSC22, LSC31, LSC33, LSC65, LSC79, LSC81, LSO2, LSO3, LSO4, LSO5, LSO6, LSO7, LSO8, LSO10 NA12, NA15, NA17, NA18, NA19, NA21, NA23, NA24, SA10, SA101, SA2, SA3, SA4, SA11, SA19 | |
*, A | TL, L | NA19, NA22, NA24, SA2, SA3, SA25, SA94 | |
TA, A | #, L | LSC12, LSC18, LSC79, LSO7, LSO10 | |
- | #, L | LSC11, LSC13, LSC61, LSC65, LSC81 | |
*, A | #, L | NA18, LSC79, LSO6, LSO7 | |
TA, A | #, L | LSC79, LSO6 |
‘+’: first records for the Aegean Sea; ‘*’: first records for Turkey's Aegean coast; ‘#’: first records for the Turkish Levantine coasts; ‘μ’: first records for the Levantine Sea; ‘-’: not found in that location. Previous records of the species in the Marmara Sea, the Turkish Aegean coasts, the Aegean Sea, the Turkish Levantine coasts and the Levantine Basin are indicated with ‘B’, ‘M’, ‘TA’, ‘A’, ‘TL’ and ‘L’, respectively (Hajderi 1995, Gücü et al. 2000, Ünal et al. 2000, Özel and Aker 2001, Aker 2002, Uysal et al. 2002, Isari et al. 2006, Uysal and Shmeleva 2012, Bakır et al. 2014, Razouls et al. 2005–2022)
Cladocera, with maximum abundance of 11,757 ind.m−3 at Station SA90, had a higher percentage of mesozooplankton at the NA and SA stations (Table 4), but a much lower mean relative abundance was observed at the LSC and LSO stations (Figure 3). A total of 7 Cladocera species (
Mean relative abundance (%), total abundance (ind m−3) and biomass (mg m−3) of dominant taxa within the total zooplankton in the Eastern Mediterranean Sea (‘−’: not found). Only taxa with a general contribution of >0.5% to the total zooplankton abundance are reported here.
Eastern Mediterranean Sea | ||||
---|---|---|---|---|
Aegean Sea | Levantine Sea | |||
Northern Aegean Sea (NA) | Southern Aegean Sea (SA) | Coastal Waters of the Levantine Sea (LSC) | Open Waters of the Levantine Sea (LSO) | |
Copepods | 28.7 | 44.3 | 77.0 | 86.8 |
7.82 | 0.43 | 0.10 | - | |
- | 0.08 | 0.81 | 3.43 | |
0.01 | 0.18 | 0.68 | 1.25 | |
0.01 | 0.19 | 6.16 | 9.08 | |
1.67 | 0.11 | 0.30 | 3.76 | |
- | - | 4.35 | - | |
0.41 | 13.70 | 2.06 | 0.01 | |
2.55 | 0.09 | 0.00 | 0.00 | |
0.00 | 0.55 | 20.92 | 28.80 | |
0.43 | 0.44 | 0.71 | 12.03 | |
0.01 | 0.00 | 0.08 | 1.56 | |
0.22 | 0.10 | 0.35 | 0.51 | |
0.04 | 0.11 | 0.10 | 1.83 | |
0.04 | 0.09 | 0.10 | 2.64 | |
6.60 | 19.03 | 16.08 | 0.59 | |
0.53 | 5.38 | 2.88 | 2.51 | |
- | - | 0.60 | - | |
0.34 | 0.50 | 1.29 | 0.21 | |
2.93 | 1.45 | 15.23 | 9.37 | |
1.51 | 0.05 | 0.53 | 2.31 | |
- | 0.03 | 0.68 | 0.41 | |
0.21 | 0.03 | 0.03 | 1.37 | |
0.17 | 0.33 | 0.53 | 0.02 | |
0.20 | 0.03 | 0.10 | 2.64 | |
Cladocera | 63.6 | 43.4 | 12.4 | 0.9 |
58.65 | 33.07 | 4.60 | - | |
3.10 | 6.95 | 3.05 | 0.11 | |
1.53 | 2.67 | 4.77 | 0.69 | |
Appendicularians | 2.1 | 3.6 | 2.8 | 1.4 |
Doliolida | 3.2 | 5.8 | 2.6 | 0.0 |
Chaetognaths | 0.7 | 0.5 | 1.2 | 2.6 |
Meroplankton | 1.5 | 2.9 | 5.4 | 3.2 |
Total abundance (ind m−3) | 3231 | 4562 | 628 | 307 |
Total biomass (mg m−3) | 300 | 748 | 316 | 231 |
Although Doliolida species were also occasionally observed (a 50% occurrence), they did not significantly contribute to the total zooplankton abundance (Table 4, Figure 3). The abundance of meroplanktonic groups, including larvae of Bivalvia, Gastropoda, Polychaeta and Echinodermata, were higher in the gulfs and the coastal stations, whereas Appendicularia were an important group in SA, with a maximum abundance of 888 ind m−3 at Station SA90 (Figure 3).
With regard to regions, 96 species were found in the NA, 98 in the SA, 124 in the LSC and 91 in the LSO. The increasing number of species from NA to LSC was more evident, except in LSO. The variability in the number of species within areas was greater in the SA and LSC regions. The most species (65 species) was recorded at Stations SA3 and LSC79 (Figure 2). The diversity index values varied between 3.7 bits (Station SA3) and 2.1 bits (Station LSC59) (Figure 2). The dominant species from the coastal waters differed from those in open waters.
Cluster analysis (Figure 4) and MDS ordination (Figure 5) of the combined data from the subregions showed that the samples were clearly differentiated by region. The among-region differences were stronger when zooplankton abundance (F3;69 = 19.885;
Dendogram for the hierarchical clustering of the 70 stations using group-average linking of Bray–Curtis similarities calculated on log-transformed abundance data. NA: northern Aegean Sea; SA: southern Aegean Sea; LSC: coastal waters of the Levantine Sea; LSO: open waters of the Levantine Sea
MDS ordination plot of 70 stations in the study area. NA: northern Aegean Sea; SA: southern Aegean Sea; LSC: coastal waters of the Levantine Sea; LSO: open waters of the Levantine Sea
Species contributing to within-group similarity as defined by SIMPER
Group and Average Similarity | Species | Similarity-to-Standard Deviation Ratio | Per cent Contribution | Cumulative Per cent Contribution |
---|---|---|---|---|
NA, 56.96 | 7.59 | 10.11 | 10.11 | |
2.55 | 10.09 | 20.20 | ||
3.17 | 7.64 | 27.84 | ||
Appendicularia | 2.06 | 6.73 | 34.57 | |
1.94 | 6.38 | 40.95 | ||
1.67 | 6.33 | 47.28 | ||
Doliolida | 1.64 | 5.75 | 53.03 | |
1.44 | 5.56 | 58.58 | ||
3.08 | 5.55 | 64.13 | ||
1.25 | 3.9 | 68.03 | ||
SA, 49.84 | 4.16 | 12.97 | 12.97 | |
6.28 | 10.39 | 23.37 | ||
1.39 | 8.88 | 32.25 | ||
1.95 | 7.24 | 39.49 | ||
1.67 | 7.19 | 46.68 | ||
Appendicularia | 1.96 | 7.16 | 53.84 | |
1.70 | 6.89 | 60.73 | ||
0.81 | 3.5 | 64.23 | ||
0.91 | 3.14 | 67.38 | ||
Chaetognatha | 0.91 | 2.88 | 70.25 | |
LSC, 50.03 | 2.09 | 12.71 | 12.71 | |
1.81 | 12.30 | 25.01 | ||
1.18 | 9.97 | 34.98 | ||
1.69 | 8.81 | 43.79 | ||
1.75 | 8.77 | 52.56 | ||
1.22 | 5.82 | 58.38 | ||
1.06 | 4.88 | 63.27 | ||
Appendicularia | 0.91 | 4.29 | 67.55 | |
LSO, 65.80 | 11.01 | 12.52 | 12.52 | |
9.95 | 9.72 | 22.24 | ||
7.08 | 9.43 | 31.67 | ||
4.70 | 8.69 | 40.36 | ||
7.16 | 6.88 | 47.24 | ||
3.70 | 5.48 | 52.71 | ||
Chaetognatha | 1.63 | 4.30 | 57.01 | |
Siphonophora | 1.24 | 3.86 | 60.87 | |
1.2 | 3.86 | 64.73 | ||
1.85 | 3.84 | 68.57 |
SIMPER analysis showed that Appendicularia, Doliolidae, some Copepoda (such as
Zooplankton species characterising the station groups, identified by clustering, determined by similarity percentage analysis (SIMPER), based on log-transformed abundance data and the Bray–Curtis similarity measure
Groups and average dissimilarity | Species | Average dissimilarity | Dissimilarity to standard deviation ratio | Percent contribution | Cumulative percent contribution |
---|---|---|---|---|---|
SA vs NA |
2.23 | 1.57 | 4.07 | 4.07 | |
2.07 | 1.88 | 3.78 | 7.85 | ||
1.99 | 1.22 | 3.63 | 11.48 | ||
1.92 | 1.71 | 3.5 | 14.98 | ||
Doliolida | 1.78 | 1.42 | 3.25 | 18.23 | |
1.71 | 0.82 | 3.11 | 21.35 | ||
1.58 | 1.27 | 2.88 | 24.22 | ||
1.54 | 1.29 | 2.8 | 27.02 | ||
1.5 | 1.27 | 2.74 | 29.76 | ||
1.45 | 1.33 | 2.64 | 32.41 | ||
Pteropoda | 1.27 | 1.07 | 2.32 | 34.73 | |
SA vs LSC |
3.37 | 1.69 | 5.81 | 5.81 | |
2.13 | 0.88 | 3.67 | 9.48 | ||
2.1 | 1.53 | 3.62 | 13.1 | ||
2.1 | 1.33 | 3.62 | 16.72 | ||
Appendicularia | 1.96 | 1.51 | 3.37 | 20.09 | |
1.91 | 1.31 | 3.29 | 23.38 | ||
1.89 | 1.14 | 3.25 | 26.63 | ||
Doliolida | 1.88 | 1.12 | 3.24 | 29.87 | |
1.82 | 1.59 | 3.13 | 33 | ||
Pteropoda | 1.53 | 1.09 | 2.63 | 35.63 | |
SA vs LSO |
4.13 | 3.5 | 6.15 | 6.15 | |
4.09 | 1.89 | 6.1 | 12.25 | ||
3 | 1.64 | 4.48 | 16.73 | ||
2.56 | 1.9 | 3.82 | 20.55 | ||
Appendicularia | 2.29 | 1.67 | 3.41 | 23.96 | |
2.27 | 2.1 | 3.39 | 27.35 | ||
2.06 | 0.77 | 3.06 | 30.41 | ||
Doliolida | 1.89 | 1.11 | 2.83 | 33.24 | |
LSC vs NA |
3.66 | 1.89 | 5.7 | 5.7 | |
3.13 | 2.42 | 4.87 | 10.57 | ||
3.06 | 1.88 | 4.77 | 15.34 | ||
2.85 | 2.35 | 4.44 | 19.78 | ||
Doliolida | 2.75 | 1.97 | 4.29 | 24.07 | |
2.24 | 2.14 | 3.48 | 27.55 | ||
1.84 | 1.41 | 2.87 | 30.42 | ||
1.83 | 1.34 | 2.85 | 33.27 | ||
LSC vs LSO 56.67 | 3.23 | 1.73 | 5.69 | 5.69 | |
2.42 | 1.74 | 4.27 | 9.96 | ||
2.39 | 1.7 | 4.21 | 14.17 | ||
2.18 | 1.6 | 3.85 | 18.02 | ||
1.82 | 1.75 | 3.21 | 21.24 | ||
1.68 | 1.8 | 2.96 | 24.2 | ||
Gastropoda | 1.64 | 1.32 | 2.89 | 27.08 | |
Appendicularia | 1.6 | 1.3 | 2.82 | 29.91 | |
NA vs LSO |
4.67 | 2.77 | 6.43 | 6.43 | |
3.43 | 4.13 | 4.72 | 11.15 | ||
3.42 | 6.92 | 4.71 | 15.86 | ||
3.23 | 2 | 4.45 | 20.3 | ||
2.9 | 2.41 | 3.99 | 24.3 | ||
Doliolida | 2.85 | 2.09 | 3.92 | 28.22 | |
2.72 | 1.9 | 3.75 | 31.97 | ||
2.38 | 3.33 | 3.27 | 35.24 |
This study provides information about the abundance and distribution of the main zooplankton species in the Aegean and Levantine Seas. In the study,
Unlike in previous years (Sever 2009), a gradual increase in mesozooplankton abundance from the northern Aegean Sea towards the southern part was observed. Previous studies (Siokou-Frangou et al. 2002, Zervoudaki et al. 2006) found that the entry of Black Sea water into the Aegean Sea via the Dardanelles caused a significant increase in phytoplankton and mesozooplankton biomass and abundance in the region. However, aquaculture and terrestrial inputs make a significant contribution to higher picophytoplankton biomass and productivity in the coastal waters of the southern Aegean and Levantine Seas (Aktan 2011, Polat 2002, Polat and Terbıyık 2013). These factors are favourable for Cladocera, primarily
In the present study, a total of 112 copepod species were discovered, of which 97 were in the Levantine Sea and 88 in the Aegean Sea. The dominance of
The Aegean Sea, particularly the southern section, has larger relative abundances of Appendicularia, which are commonly linked with abundant particulate organic aggregates (Alldredge 1976), and thus play an essential role in pelagic food webs and carbon transfer downward (Gorsky et al. 1991). Their significant relative importance in the southern Aegean Sea suggests that the water column in these areas was richer in particulate organic material and, in general, smaller particles. The highest nutrient levels and the lowest transparency levels were found at several stations in the LSC region, due to local tourism, domestic sewage discharge, industrial wastewater and marina activities and marine traffic, as well as in the SA region, due to intensive aquaculture and limited water exchange with the sea (Aktan 2011).
Eutrophication may have an indirect effect on zooplankton species diversity through its effect on phytoplankton (Shiganova et al. 1998). The abundance of
The cluster diagram (Figure 4) and MDS representation (Figure 5) showed that Stations NA17 and LSC59 were starkly different from the other sampling stations, mainly due to their low number of species and unique species composition. Both stations present very particular conditions, which most likely were responsible for their singularity in terms of the zooplankton. An interesting finding for Station NA17 was the registration of
The current study provides information on broader forms of zooplankton community structure in the Eastern Mediterranean, ranging from coastal to open water areas. Detailed future investigations are required to better understand the impact of zooplankton on coastal ecosystems due to growing anthropogenic and climatic pressures. Furthermore, the ecological significance of zooplankton, both in the oligotrophic eastern Mediterranean Sea and in coastal environments with changing trophic status, should be investigated further.