Assessment of the Lower Danube Sediment Regime and Morphology for the Identification of Habitats for Critically Endangered Sturgeon †
Abstract
:1. Introduction
- Sieving using sieves (grain diameter d > 2.00 mm);
- In situ sieving method (0.05–0.08 (0.063) < d< 2.00 mm);
- Sedimentation method (d < 0.05–0.08 (0.063) mm).
- The frequency curve, which is a graphical depiction of a string that consists of pairs of particle size classes and their corresponding fractions—a histogram representing the simple frequency distribution in percentage [%] and the proportion of involvement for each distinct size class.
- The cumulative frequency refers to the total accumulation of frequencies in a dataset. The cumulative percentage involvement refers to the total proportion of each particle size class up to a specific diameter value.
2. Materials and Methods
2.1. Sampling Campaigns
2.2. Granulometric Assessment
- The median, also known as D50, is the diameter value that splits the particle size distribution into two equal sections, with 50% of the particles having a diameter smaller than or equal to this value. Additional significant values are the size values corresponding to the selected cumulative frequencies equidistant from D50: D16 and D84, D5 and D95, and D25 and D75.
- The graphical mean of a distribution refers to the arithmetic mean of frequencies that are equidistant from the 50th percentile.
- Standard deviation corresponds to the dispersion of size values within the distribution around the mean of 50%.
- The skewness index, also known as the mean squared deviation, quantifies the extent to which values are dispersed in a frequency distribution.
- The kurtosis index quantifies the degree to which values in a frequency distribution are concentrated in a certain region.
3. Results and Discussion
4. Conclusions
Author Contributions
Funding
Institutional Review Board Statement
Informed Consent Statement
Data Availability Statement
Acknowledgments
Conflicts of Interest
References
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Sample | Sieve Diameter [mm] | 2 | 1 | 0.5 | 0.25 | 0.16 | 0.09 | <0.09 | Total |
---|---|---|---|---|---|---|---|---|---|
PS_Bala_1 | Sieve debris [g] | 0.000 | 0.000 | 0.410 | 36.300 | 202.099 | 45.601 | 3.027 | 287.437 |
Gravimetric percentage [%] | 0.000 | 0.000 | 0.143 | 12.629 | 70.311 | 15.865 | 1.053 | 100.000 | |
PS_Bala_2 | Sieve debris [g] | 0.000 | 0.000 | 0.445 | 16.800 | 170.232 | 51.250 | 5.575 | 244.302 |
Gravimetric percentage [%] | 0.000 | 0.000 | 0.182 | 6.877 | 69.681 | 20.978 | 2.282 | 100.000 | |
PS_Bala_3 | Sieve debris [g] | 0.000 | 3.494 | 10.695 | 20.528 | 77.361 | 84.371 | 33.278 | 229.727 |
Gravimetric percentage [%] | 0.000 | 1.521 | 4.656 | 8.936 | 33.675 | 36.727 | 14.486 | 100.000 | |
PS_Bala_4 | Sieve debris [g] | 0.000 | 16.020 | 17.066 | 32.880 | 58.466 | 67.134 | 27.154 | 218.720 |
Gravimetric percentage [%] | 0.000 | 7.324 | 7.803 | 15.033 | 26.731 | 30.694 | 12.415 | 100.000 | |
PS_Bala_5 | Sieve debris [g] | 0.000 | 6.160 | 42.221 | 43.202 | 39.342 | 29.983 | 18.565 | 179.473 |
Gravimetric percentage [%] | 0.000 | 3.432 | 23.525 | 24.072 | 21.921 | 16.706 | 10.344 | 100.000 |
Sample | Sieve Diameter [mm] | 2 | 1 | 0.5 | 0.25 | 0.16 | 0.09 | <0.09 | Total |
---|---|---|---|---|---|---|---|---|---|
PS_Caleia_1 | Sieve debris [g] | 5.804 | 8.570 | 5.430 | 16.336 | 26.329 | 98.050 | 42.474 | 202.993 |
Gravimetric percentage [%] | 2.859 | 4.222 | 2.675 | 8.048 | 12.970 | 48.302 | 20.924 | 100.000 | |
PS_Caleia_2 | Sieve debris [g] | 5.806 | 11.937 | 6.274 | 9.249 | 14.010 | 85.940 | 66.399 | 199.615 |
Gravimetric percentage [%] | 2.909 | 5.980 | 3.143 | 4.633 | 7.019 | 43.053 | 33.264 | 100.000 | |
PS_Caleia_3 | Sieve debris [g] | 6.225 | 11.220 | 5.640 | 2.933 | 14.639 | 117.176 | 42.572 | 200.405 |
Gravimetric percentage [%] | 3.106 | 5.599 | 2.814 | 1.464 | 7.305 | 58.470 | 21.243 | 100.000 | |
PS_Caleia_4 | Sieve debris [g] | 6.059 | 10.039 | 7.598 | 41.958 | 54.362 | 69.538 | 29.371 | 218.925 |
Gravimetric percentage [%] | 2.768 | 4.586 | 3.471 | 19.165 | 24.831 | 31.763 | 13.416 | 100.000 | |
PS_Caleia_5 | Sieve debris [g] | 4.015 | 18.340 | 14.690 | 21.061 | 16.759 | 65.102 | 60.015 | 199.982 |
Gravimetric percentage [%] | 2.008 | 9.171 | 7.346 | 10.531 | 8.380 | 32.554 | 30.010 | 100.000 |
Sample | Standard Deviation | Skewness Index | Kurtosis Index |
---|---|---|---|
PS_Bala_1 | 0.042 | 1.078 | 0.810 |
PS_Bala_2 | 0.052 | 0.171 | 1.112 |
PS_Bala_3 | 0.119 | 0.342 | 2.054 |
PS_Bala_4 | 0.251 | 0.641 | 2.055 |
PS_Bala_5 | 0.276 | 0.535 | 0.839 |
Sample | Standard Deviation | Skewness Index | Kurtosis Index |
---|---|---|---|
PS_Caleia_1 | 0.274 | 0.724 | 5.670 |
PS_Caleia_2 | 0.298 | 0.717 | 10.022 |
PS_Caleia_3 | 0.278 | 0.609 | 11.023 |
PS_Caleia_4 | 0.305 | 0.675 | 2.987 |
PS_Caleia_5 | 0.398 | 0.838 | 2.517 |
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Sadîca, I.; Tudor, G.; Holban, E.; Arsene, M.; Carachiciu, M.; Cucu, G.; Stegărescu, S. Assessment of the Lower Danube Sediment Regime and Morphology for the Identification of Habitats for Critically Endangered Sturgeon. Environ. Earth Sci. Proc. 2025, 33, 9. https://doi.org/10.3390/eesp2025033009
Sadîca I, Tudor G, Holban E, Arsene M, Carachiciu M, Cucu G, Stegărescu S. Assessment of the Lower Danube Sediment Regime and Morphology for the Identification of Habitats for Critically Endangered Sturgeon. Environmental and Earth Sciences Proceedings. 2025; 33(1):9. https://doi.org/10.3390/eesp2025033009
Chicago/Turabian StyleSadîca, Isabela, Georgeta Tudor, Elena Holban, Miruna Arsene, Maria Carachiciu, George Cucu, and Sorin Stegărescu. 2025. "Assessment of the Lower Danube Sediment Regime and Morphology for the Identification of Habitats for Critically Endangered Sturgeon" Environmental and Earth Sciences Proceedings 33, no. 1: 9. https://doi.org/10.3390/eesp2025033009
APA StyleSadîca, I., Tudor, G., Holban, E., Arsene, M., Carachiciu, M., Cucu, G., & Stegărescu, S. (2025). Assessment of the Lower Danube Sediment Regime and Morphology for the Identification of Habitats for Critically Endangered Sturgeon. Environmental and Earth Sciences Proceedings, 33(1), 9. https://doi.org/10.3390/eesp2025033009