Benthic nutrients and oxygen fluxes at the water sediment interface in a pearl farming atoll (Ahe, Tuamotu, French Polynesia). (December 2021)

• Record Type: Journal Article
• Authors: Grenz, Christian; Rodier, Martine; Seceh, Claire; Varillon, David; Haumani, Gabriel; Pinazo, Christel
• Is Part Of: Marine pollution bulletin. Volume 173:Part A(2021)
• Publication Date: 2021-12
• Subjects: Benthic nutrient fluxes -- Sediment respiration -- Phytobenthic production -- Atoll lagoon -- Pearl farming -- French Polynesia; Marine pollution -- Periodicals; Marine Biology -- Periodicals; Water Pollution -- Periodicals; Mer -- Pollution -- Périodiques; Publications périodiques; Pollution des mers; Lutte antipollution; Electronic journals; 363.7394
• DOI: 10.1016/j.marpolbul.2021.112963
• Languages: English
• ISSNs: 0025-326X

Abstract

Abstract: Benthic exchanges of oxygen and nutrient at the sediment-water interface were investigated under light and dark conditions at 5 selected sites in a sub-tropical atoll. Mean oxygen fluxes were - 1316.5 ± 242.0 μmol m −2 h −1 and mean effluxes of oxygen under light conditions were 2231.7 ± 626.4 μmol m −2 h −1, presumably due to microphytobenthos present at the sediment-water interface. The consequences of this high related productivity was a systematic consumption of nutrients (DIN, PO4 and Si(OH)4 ) during almost all light incubations, contrasting with the effluxes of nutrients during dark incubations. Our results suggest that the sediments were net autotrophic and the oxygen balance in favor of microbenthic production when compared to community demand. Diurnal rates of gross benthic primary productivity were high (3423 ± 1192 μmol m −2 h −1 ) which emphasize the role of microphytobenthos in maintaining the oxygen reservoir in tropical lagoons. Highlights: The study reports benthic oxygen exchanges and nutrient fluxes in a pearl farming lagoon. Nutrients were consumed during daylight and released at dark. The sediment was net autotrophic and microphytobenthos maintained oxic conditions. The sediment played a major role in organic matter recycling in the lagoon.