Seasonal coupling and de-coupling of net calcification rates from coral reef metabolism and carbonate chemistry at Ningaloo Reef, Western Australia - Université de La Réunion Accéder directement au contenu
Article Dans Une Revue Journal of Geophysical Research. Oceans Année : 2012

Seasonal coupling and de-coupling of net calcification rates from coral reef metabolism and carbonate chemistry at Ningaloo Reef, Western Australia

Résumé

Rates of net production, net calcification, and nutrient uptake were measured in a coral-dominated reef flat community on Ningaloo Reef in northwestern Australia under seasonally minimum and maximum light levels. Daily integrated light decreased twofold while water temperatures remained relatively constant increasing by only 1°C on average from summer to winter. Rates of daily community gross primary production (GPP) were only 33% ± 9% higher in summer than in winter (1400 ± 70 versus 1050 ± 60 mmol C m−2 d−1), far less than the twofold seasonal changes reported for most shallow reef communities. Rates of daily community net calcification (Gnet) were not significantly different between seasons (190 ± 40 mmol CaCO3 m−2 d−1 in summer versus 200 ± 10 mmol CaCO3 m−2 d−1 in winter). The average rate of total nitrogen uptake (dissolved + particulate) was also not significantly different between summer and winter (8.3 ± 3.8 versus 6.6 ± 3.4 mmol N m−2 d−1, respectively), despite evidence of sporadically high nitrate uptake in both seasons. In summer, rates of hourly net calcification (gnet) were linearly correlated with diurnal changes in net production, pH, and aragonite saturation state (Ωar); and were mostly correlated with light except at mid-day under heavy cloud cover. However, in winter,gnet was independent of diurnal changes in light, net production, pH, and Ωar indicating that the reef flat community had possibly reached a threshold above which rates of net calcification were insensitive to diurnal changes in their environment.
Fichier principal
Vignette du fichier
Seasonal_coupling_calcification_rates.pdf (789.86 Ko) Télécharger le fichier
Origine : Fichiers éditeurs autorisés sur une archive ouverte
Loading...

Dates et versions

hal-01368981 , version 1 (15-06-2018)

Identifiants

Citer

James L. Falter, Ryan J. Lowe, Marlin J. Atkinson, Pascale Cuet. Seasonal coupling and de-coupling of net calcification rates from coral reef metabolism and carbonate chemistry at Ningaloo Reef, Western Australia. Journal of Geophysical Research. Oceans, 2012, 117 (C5), pp.n/a - n/a. ⟨10.1029/2011JC007268⟩. ⟨hal-01368981⟩
108 Consultations
375 Téléchargements

Altmetric

Partager

Gmail Facebook X LinkedIn More