Subcellular view of host-microbiome nutrient exchange in sponges: insights into the ecological success of an early metazoan-microbe symbiosis.

BackgroundSponges are increasingly recognised as key ecosystem engineers in many aquatic habitats. They play an important role in nutrient cycling due to their unrivalled capacity for processing both dissolved and particulate organic matter (DOM and POM) and the exceptional metabolic repertoire of their diverse and abundant microbial communities. Functional studies determining the role of host and microbiome in organic nutrient uptake and exchange, however, are limited. Therefore, we coupled pulse-chase isotopic tracer techniques with nanoscale secondary ion mass spectrometry (NanoSIMS) to visualise the uptake and translocation of 13C- and 15N-labelled dissolved and particulate organic food at subcellular level in the high microbial abundance sponge Plakortis angulospiculatus and the low microbial abundance sponge Halisarca caerulea.ResultsThe two sponge species showed significant enrichment of DOM- and POM-derived 13C and 15N into their tissue over time. Microbial symbionts were actively involved in the assimilation of DOM, but host filtering cells (choanocytes) appeared to be the primary site of DOM and POM uptake in both sponge species overall, via pinocytosis and phagocytosis, respectively. Translocation of carbon and nitrogen from choanocytes to microbial symbionts occurred over time, irrespective of microbial abundance, reflecting recycling of host waste products by the microbiome.ConclusionsHere, we provide empirical evidence indicating that the prokaryotic communities of a high and a low microbial abundance sponge obtain nutritional benefits from their host-associated lifestyle. The metabolic interaction between the highly efficient filter-feeding host and its microbial symbionts likely provides a competitive advantage to the sponge holobiont in the oligotrophic environments in which they thrive, by retaining and recycling limiting nutrients. Sponges present a unique model to link nutritional symbiotic interactions to holobiont function, and, via cascading effects, ecosystem functioning, in one of the earliest metazoan-microbe symbioses. Video abstract

An investigation of the relation between the number of children and education in Italy

In this paper we have investigated the impact of the level of education on the number of children in Italy. We have selected 1,490 families from the 1997- 2005 Longitudinal Investigation on Italian Families (ILFI) dataset. Our dependent variable is represented by the number of children ever born to each respondent (and to his partner). Since the number of children ever born (CEB) is a count variable, we have implemented three empirical models: Poisson, Zero-Truncated Poisson and an Instrumental Variable Poisson, where grandparents’ education is exerted as an instrument of parents’ education. In particular, we have considered two stages for each model: in the first stage, we have estimated the impact of female’s education on her number of children, and in the second one, we have used also partner’s education to identify the previous effect. From the empirical results, we may observe a significant negative effect of the level of education on the number of children

Impacts of 1.5°C Global Warming on Natural and Human Systems

An IPCC Special Report on the impacts of global warming of 1.5°C above pre-industrial levels and related global greenhouse gas emission pathways, in the context of strengthening the global response to the threat of climate change, sustainable development, and efforts to eradicate povert

Data for: Photosynthesis by symbiotic sponges enhances their ability to erode calcium carbonate

Data File 1. Nexus file containing sequence alignments of chloroplast large subunit rDNA (cp23S) from control and experimental sponges, used to generate Figure 3E. Data File 2. Nexus file containing sequence alignments of the coding and non-coding region of the psbA chloroplast gene from control and experimental sponges, used to generate Figure 3F

Data for: Photosynthesis by symbiotic sponges enhances their ability to erode calcium carbonate

Data File 1. Nexus file containing sequence alignments of chloroplast large subunit rDNA (cp23S) from control and experimental sponges, used to generate Figure 3E. Data File 2. Nexus file containing sequence alignments of the coding and non-coding region of the psbA chloroplast gene from control and experimental sponges, used to generate Figure 3F

Bleaching and mortality of a photosymbiotic bioeroding sponge under future carbon dioxide emission scenarios

202308 bckwAccepted ManuscriptOthersGreat Barrier Reef Foundation; Australian Research Council (ARC) Centre of Excellence for Coral Reef Studies; ARC Linkage; Queensland Smart State Fellowship; International Society for Reef Studies Graduate FellowshipPublishe

Sponge bioerosion on changing reefs : ocean warming poses physiological constraints to the success of a photosymbiotic excavating sponge

2017-2018 > Academic research: refereed > Publication in refereed journal201805_bcmaVersion of RecordPublishe

Single-cell measurement of ammonium and bicarbonate uptake within a photosymbiotic bioeroding sponge

© 2018 International Society for Microbial Ecology. Some of the most aggressive coral-excavating sponges host intracellular dinoflagellates from the genus Symbiodinium, which are hypothesized to provide the sponges with autotrophic energy that powers bioerosion. Investigations of the contribution of Symbiodinium to host metabolism and particularly inorganic nutrient recycling are complicated, however, by the presence of alternative prokaryotic candidates for this role. Here, novel methods are used to study nutrient assimilation and transfer within and between the outer-layer cells of the Indopacific bioeroding sponge Cliona orientalis. Combining stable isotope labelling, transmission electron microscopy (TEM) and nanoscale secondary ion mass spectrometry (NanoSIMS), we visualize and measure metabolic activity at the individual cell level, tracking the fate of 15N-ammonium and 13C-bicarbonate within the intact holobiont. We found strong uptake of both inorganic sources (especially 13C-bicarbonate) by Symbiodinium cells. Labelled organic nutrients were translocated from Symbiodinium to the Symbiodinium-hosting sponge cells within 6 h, and occasionally to other sponge cells within 3 days. By contrast, prokaryotic symbionts were not observed to participate in inorganic nutrient assimilation in the outer layers of the sponge. Our findings strongly support the metabolic interaction between the sponge and dinoflagellates, shedding light on the ecological advantages and adaptive capacity of photosymbiotic bioeroding sponges in oligotrophic marine habitats