TABLE 5.
Comparison of exoenzyme activities in eastern Mediterranean sapropels with values from the literature
| Study area | Water depth (m) | Sediment depth (cmbsf)a |
Vmax
(nmol cm−3 sediment h−1)
|
Reference | |
|---|---|---|---|---|---|
| β-Glucosidase | Aminopeptidase | ||||
| NE Atlantic | |||||
| Biotrans area; 47°N, 19°W | 4,500 | 0–1 | 0.089 | 15 | 8 |
| NE Atlantic; 47°N, 19°W | 4,555–4,919 | 0–10 | <0.002–0.10 | 10.0–23.0 | 52 |
| Celtic Sea; 50°N, 10°W | 580–1,680 | 1–2 | 0.03–0.43 | 9.5–45 | 53 |
| NW Mediterranean; 40°N, 3°E | 1,230 | 1–2 | NDd | 576 | 61 |
| Eastern Mediterranean | |||||
| Ionean Sea; 37°N, 18°E | 993–4,617 | 0–1 | 0.33–2.13 | 109–284 | 11 |
| Levantine Sea; core M40/4-69/2SL; hemipelagic layers | 2,150 | 4–6 (Z0) | 0.0084 ± 0.0005 | 2.52 ± 0.00 | This work |
| 89–91 (Z1) | 0.0060 ± 0.0022 | 0.134 ± 0.031 | |||
| 304–306 (Z3) | 0.0335 ± 0.0143 | 0.036 ± 0.002 | |||
| 356–358 (Z4) | 0.0653 ± 0.0024 | 0.022 ± 0.001 | |||
| Levantine Sea, core M40/4-69/2SL; sapropel layers | 2,150 | 25–27 (S1) | 0.0309 ± 0.0107 | 1.78 ± 0.05 | This work |
| 281–283 (S3) | 0.0282 ± 0.0282 | 0.78 ± 0.04 | |||
| 337–339 (S4) | <0.015b | 1.20 ± 0.07 | |||
| 387–389 (S5) | <0.015b | 1.04 ± 0.13 | |||
| Urania basin; eastern Mediterranean | 3,600 | 0–4 | 0.120 ± 0.001 | 0.323 ± 0.002 | This work |
| Levantine Sea; 33°N, 29°E | 990–4,260 | 0–1 | 0.08–1.24 | 14–118 | 11 |
| Arctic circle | |||||
| Barents Sea; 82°N, 42°E | 1,013 | 0–4.5 | 0.2–0.4 | 67–144 | 10 |
| Laptev Sea | 796–3,427 | 0–1 | 0.02–0.36 | 21–116 | 9 |
| Amundsen Basin; 87°N, 68°E | 4,480 | 0–1 | 0.017 | 73.4 | 9 |
| Lomosov Ridge; 87°N, 153°E | 3,413 | 0–1 | 0 | 19.6 | 9 |
| Intertidal mudflats | |||||
| Lowes Cove, Maine | 0 | 0–2 | 23.2 | ND | 34 |
| Lowes Cove, Maine | 0 | 0–1 | ND | 12c | 39 |
| Dangast, German Wadden Sea; 53°27′N, 8°7′E | 0 | 3.5–8.5 | 20.6 ± 1.9 | 6.07 ± 1.06 | This work |
| 0 | 0–5 | 16.6 ± 2.8 | 86.0 ± 25.7 | This work | |
| Schillig, German Wadden Sea; 53°42′N, 8°01′E | 0 | 6–11 | 5.12 ± 0.16 | 33.1 ± 7.5 | This work |
a
cmbsf, centimeters below surface. The layer number is in parentheses.
b
Due to the high autofluorescence of sapropel supernatants, the detection limit for exoenzyme activity was 0.015 nmol · cm−3 · h−1. The detection limit for exoenzyme activity in the hemipelagic carbon-poor layers was 0.003 nmol · cm−3 · h−1.
c
Exoenzyme activities were available only in units of nanomoles · (grams of sediment · hour)−1.
d
ND, not detected.