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| Titel |
Community metabolism in shallow coral reef and seagrass ecosystems, Lower Florida Keys |
| VerfasserIn |
Daniela Turk, Kimberly Yates, Maria Vega-Rodriguez, Gerardo Toro-Farmer, Chris L'Esperance, Nelson Melo, Deanesh Ramsevak, Sergio Cerdeira-Estrada, Frank Muller-Karger, Stanley Herwitz, Wade McGillis |
| Konferenz |
EGU General Assembly 2015
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 17 (2015) |
| Datensatznummer |
250114211
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| Publikation (Nr.) |
 EGU/EGU2015-14695.pdf |
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| Zusammenfassung |
| Diurnal variation of net community production (NEP) and net community calcification
(NEC) were measured in coral reef and seagrass biomes during October 2012 in the lower
Florida Keys using a mesocosm enclosure and the oxygen gradient flux technique. Seagrass
and coral reef sites showed diurnal variations of NEP and NEC with positive values
at near-bottom light levels above 100-300 μEinstein m-2 s-1. During daylight
hours, seagrasses showed an average NEP of 12.3 mmol O2 m-2 h-1 compared to
daylight coral reef NEP of 8.6 mmol O2 m-2 h-1. At night, NEP at the seagrass was
relatively constant, while in the coral reef, net respiration was highest immediately after
dusk and decreasing during the rest of the night. NEC values were ranging from
0.20 g CaCO3 m-2 h-1 during daylight to -0.15 g CaCO3 m-2 h-1 at night at
the seagrass site, and from 0.17 to -0.10 g CaCO3 m-2 h-1 at the coral reef site.
Similar NEC:NEP ratios were observed at the seagrass site and the coral site at
the time of maximum daily irradiance. Average photosynthetic quotient (PQ) at
the seagrass site was slightly lower in the morning and early afternoon than at the
coral reef site, and higher at the seagrass site in the late afternoon. There were no
significant differences in pH and aragonite saturation states (Ωar) between the seagrass
and coral reef sites. Decrease in light levels during thunderstorms significantly
decreased NEP, transforming the system from net autotrophic to net heterotrophic. |
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