Table 2. Enrichment experiments with different organic carbon concentrations and coral species.
All previous studies were conducted with hard corals in ambient reef temperature and showed negative impacts of elevated glucose compared to control treatments with ambient glucose levels. The present study showed neutral effects of glucose addition in combination with ambient temperature and positive effects of glucose on pulsation rates and mortality of soft corals compared to control treatments in elevated temperature. Negative (–), positive (+) and neutral (o) implications for corals are indicated.
| Study | Species | Glucose concentration (mg/L) | Time (days) | Results (compared to control) | Implications |
|---|---|---|---|---|---|
| Pogoreutz et al. (2017) | Pocillopora verrucosa | 10 | 28 | Pronounced paling | – |
| Kline et al. (2006) | Orbicella annularis (Ellis & Solander, 1786) | 12.5 25 |
30 | 5-fold higher, significant mortality in both levels | – |
| Kuntz et al. (2005) |
O. annularis, Agaricia tenuifolia, Porites furcata |
5 25 (lactose addition) |
30 | Species-specific higher mortality rate | – |
| Haas, Al-Zibdah & Wild (2009) | Acropora | 110 | 90 | Reduced chlorophyll a tissue concentration, colour decrease | – |
| This study | Xenia umbellata | 10 20 40 |
21 | No significant effect | o |
| This study | Xenia umbellata | 10 20 40 |
45 | Significantly higher pulsation rate, reduced mortality in all treatments | + |