Phosphorus metabolism of reef organisms with algal symbionts

Abstract

Phosphorus (P), an essential structural and functional component of all living organisms, is considered to be the ultimate limiting nutrient in marine ecosystems. To optimize its acquisition, marine species such as protozoa, sponges, foraminifera, clams, and reef corals, among others, have entered symbiotic relationships with algae, which recycle waste products of the animal host and transform dissolved inorganic nutrients into organic molecules, making them bioavailable to their host. Such associations provide a competitive edge in an environment where ambient nutrient availability is low. The aim of this review is to summarize the current knowledge on the P sources available to reef organisms with algal symbionts, to discuss the means by which P is taken up and stored within the symbiosis, and to assess the effects of eutrophication‐induced phosphate enrichment on the algal and host physiology. Finally, we give an overview of knowledge gaps and open questions that should be addressed to better understand the role of phosphorus in reef symbioses functioning.

Sugar enrichment provides evidence for a role of nitrogen fixation in coral bleaching

“…() recently showed that the direct transfer of fixed N and heterotrophic ingestion of diazotrophs provides a non‐negligible and important N source for Symbiodinium . This uptake of additional N from N 2 fixation can explain the observed 40% increase in the N:P ratio in Symbiodinium cells in the current study, which are in general constant (Ferrier‐Pagès, Godinot, D'Angelo, Wiedenmann, & Grover, ). Further, the shift in algal symbiont nutrient stoichiometry suggests that excess N uptake released Symbiodinium from their N‐limited state, an important regulatory mechanism maintaining the coral–algae symbiosis (Falkowski et al., ).…”

Coral reef carbonate budgets and ecological drivers in the naturally high temperature and high alkalinity environment of the Red Sea

“…A T was indeed the strongest predictor for both G net and G budget , alone explaining more than half of the variation in reef growth rates in the present study. Interestingly, our study also identifies PO 4 3− concentration, an essential macronutrient and important source of energy for primary producers and reef calcifiers (Ferrier-Pagès et al, 2016), to be a strong abiotic correlate of reef growth. While an overload of inorganic nutrients can be detrimental for the calcification process (Fabricius, 2005; Tambutté et al, 2011), our results show that in a highly oligotrophic reef system, such as the Red Sea, reef growth might be positively affected by seasonal increases in PO 4 3− levels.…”

Estimates of fish and coral larvae as nutrient subsidies to coral reef ecosystems

“…, Ferrier‐Pages et al. ), but we still know relatively little about how these processes transcend to the ecosystem scale. To improve understanding of these processes at larger scales of organization, exhaustive knowledge of all the components that underpin a coral reef nutrient budget is needed.…”

“…Human activities are altering the nutrient budgets of coral reefs worldwide, through myriad ways, but the mechanisms that underlie these interactions remain poorly understood (Szmant 2002). Recent research is improving understanding of coral-nutrient interactions at the organismlevel (Wiedenmann et al 2013, Ferrier-Pages et al 2016), but we still know relatively little about how these processes transcend to the ecosystem scale. To improve understanding of these processes at larger scales of organization, exhaustive knowledge of all the components that underpin a coral reef nutrient budget is needed.…”