Regulation of Nitrate Uptake by the Seagrass Zostera marina During Upwelling
| Autor: | José A. Zertuche-González, Jose Miguel Sandoval-Gil, Alejandro Cabello-Pasini, José Martín Hernández-Ayón, Victor F. Camacho-Ibar, María del Carmen Ávila-López |
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| Rok vydání: | 2019 |
| Předmět: |
inorganic chemicals
0106 biological sciences 010504 meteorology & atmospheric sciences Ecology biology organic chemicals 010604 marine biology & hydrobiology food and beverages Aquatic Science biology.organism_classification 01 natural sciences chemistry.chemical_compound Seagrass Oceanography Water column Nutrient Nitrate chemistry Dissolved organic carbon Environmental science Zostera marina Upwelling Bay Ecology Evolution Behavior and Systematics 0105 earth and related environmental sciences |
| Zdroj: | Estuaries and Coasts. 42:731-742 |
| ISSN: | 1559-2731 1559-2723 |
| Popis: | Prolonged nitrogen (N) fertilization can impact seagrass survival and productivity; however, the effects of N enrichment pulses (e.g., upwelling or sediment resuspension) remain poorly understood. This study examined the effects of short-term (1 h) pulsing of nitrate (NO3−) enrichment, simulating an upwelling event, on dissolved inorganic carbon (DIC) and NO3− uptake capacities, critical in controlling eelgrass productivity. Zostera marina dominates submerged vegetation in coastal lagoons influenced by upwelling in the California Current system. Laboratory incubations were conducted in winter (non-upwelling) and spring (upwelling) with shoots collected from San Quintin Bay meadows, Baja California, Mexico, differentially exposed to upwelled NO3−. Results suggest that NO3− enrichment stimulated DIC and NO3− uptake in winter, reflecting the close relationship between carbon metabolism and NO3− assimilation. Eelgrass shoots showed reduced NO3− incorporation in spring; neither NO3− uptake nor photosynthesis increased when exposed to high NO3−. Saturation of spring shoots at lower ambient NO3− concentrations may be interpreted as a physiological strategy to restrict metabolically costly NO3− incorporation during upwelling; this regulation of NO3− uptake strongly contrasts to the apparently full exploitation of this nutrient by seaweeds also dominant within the bay, as indicated in previous works. Despite their reduced NO3− uptake, eelgrass meadows near the bay mouth acquire NO3− at rates up to 4.2 mmol N m−2 day−1. This represents non-trivial water column NO3− removal compared to the estimated oceanic NO3− supply (~ 7.1 mmol m−2 day−1) during upwelling, highlighting the importance of Z. marina beds in controlling the lagoonal N-budget. |
| Databáze: | OpenAIRE |
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