With or without nutrients, sponges are boring: No effect of inorganic nutrients on clionaid sponge bioerosion of carbonate substrate.

Sponge bioerosion is an important process on many carbonate reef ecosystems. Eutrophication has been linked with an increase in boring sponge abundance and biomass in coral reefs, yet the impacts on sponge bioerosion rates remain largely unexplored within oyster reef communities. The present study evaluated the impacts of nitrate and phosphate addition on the bioerosion of Cliona celata inhabiting carbonate substrates in the subtropical southeastern U.S. Using in situ and aquarium manipulations, sponge bioerosion rates were compared among control and nutrient addition treatments in three experiments. Overall, there were no differences in loss of calcium carbonate substrate among treatments in any of the experiments, though very high rates of bioerosion (up to 0.11 g CaCO3 day-1) were observed in the field experiments. Future research should consider the impacts of both inorganic and organic nutrient loading to fully understand the impacts of eutrophication on boring sponge ecology in subtropical oyster reefs.

Comparative transcriptomics reveals altered species interaction between the bioeroding sponge Cliona varians and the coral Porites furcata under ocean acidification.

Bioeroding sponges interact and compete with corals on tropical reefs. Experimental studies have shown global change alters this biotic interaction, often in favour of the sponge. Ocean acidification in particular increases sponge bioerosion and reduces coral calcification, yet little is known about the molecular basis of these changes. We used RNA-Seq data to understand how acidification impacts the interaction between the bioeroding sponge, Cliona varians, and the coral, Porites furcata, at the transcriptomic level. Replicate sponge and coral genets were exposed to ambient (8.1 pH) and acidified (7.6 pH) conditions in isolation and in treatments where they were joined for 48 h. The coral had a small gene expression response (tens of transcripts) to the sponge, suggesting it does little at the transcriptomic level to deter sponge overgrowth. By contrast, the sponge differentially expressed 7320 transcripts in response to the coral under ambient conditions and 3707 transcripts in response to acidification. Overlap in the responses to acidification and the coral, 2500 transcripts expressed under both treatments, suggests a similar physiological response to both cues. The sponge expressed 50× fewer transcripts in response to the coral under acidification, suggesting energetic costs of bioerosion, and other cellular processes, are lower for sponges under acidification. Our results suggest how acidification drives ecosystem-level changes in the accretion/bioerosion balance on coral reefs. This shift is not only the result of changes to the thermodynamic balance of these chemical reactions but also the result of active physiological responses of organisms to each other and their abiotic environment.

Unprofessional peer reviews disproportionately harm underrepresented groups in STEM.

BACKGROUND: Peer reviewed research is paramount to the advancement of science. Ideally, the peer review process is an unbiased, fair assessment of the scientific merit and credibility of a study; however, well-documented biases arise in all methods of peer review. Systemic biases have been shown to directly impact the outcomes of peer review, yet little is known about the downstream impacts of unprofessional reviewer comments that are shared with authors. METHODS: In an anonymous survey of international participants in science, technology, engineering, and mathematics (STEM) fields, we investigated the pervasiveness and author perceptions of long-term implications of receiving of unprofessional comments. Specifically, we assessed authors' perceptions of scientific aptitude, productivity, and career trajectory after receiving an unprofessional peer review. RESULTS: We show that survey respondents across four intersecting categories of gender and race/ethnicity received unprofessional peer review comments equally. However, traditionally underrepresented groups in STEM fields were most likely to perceive negative impacts on scientific aptitude, productivity, and career advancement after receiving an unprofessional peer review. DISCUSSION: Studies show that a negative perception of aptitude leads to lowered self-confidence, short-term disruptions in success and productivity and delays in career advancement. Therefore, our results indicate that unprofessional reviews likely have and will continue to perpetuate the gap in STEM fields for traditionally underrepresented groups in the sciences.

Testing the relationship between microbiome composition and flux of carbon and nutrients in Caribbean coral reef sponges.

BACKGROUND: Sponges are important suspension-feeding members of reef communities, with the collective capacity to overturn the entire water column on shallow Caribbean reefs every day. The sponge-loop hypothesis suggests that sponges take up dissolved organic carbon (DOC) and, via assimilation and shedding of cells, return carbon to the reef ecosystem as particulate organic carbon (POC). Sponges host complex microbial communities within their tissues that may play a role in carbon and nutrient cycling within the sponge holobiont. To investigate this relationship, we paired microbial community characterization (16S rRNA analysis, Illumina Mi-Seq platform) with carbon (DOC, POC) and nutrient (PO4, NOx, NH4) flux data (specific filtration rate) for 10 common Caribbean sponge species at two distant sites (Florida Keys vs. Belize, ~ 1203 km apart). RESULTS: Distance-based linear modeling revealed weak relationships overall between symbiont structure and carbon and nutrient flux, suggesting that the observed differences in POC, DOC, PO4, and NOx flux among sponges are not caused by variations in the composition of symbiont communities. In contrast, significant correlations between symbiont structure and NH4 flux occurred consistently across the dataset. Further, several individual symbiont taxa (OTUs) exhibited relative abundances that correlated with NH4 flux, including one OTU affiliated with the ammonia-oxidizing genus Cenarchaeum. CONCLUSIONS: Combined, these results indicate that microbiome structure is uncoupled from sponge carbon cycling and does not explain variation in DOC uptake among Caribbean coral reef sponges. Accordingly, differential DOC assimilation by sponge cells or stable microbiome components may ultimately drive carbon flux in the sponge holobiont.

Sponge erosion under acidification and warming scenarios: differential impacts on living and dead coral.

Ocean acidification will disproportionately impact the growth of calcifying organisms in coral reef ecosystems. Simultaneously, sponge bioerosion rates have been shown to increase as seawater pH decreases. We conducted a 20-week experiment that included a 4-week acclimation period with a high number of replicate tanks and a fully orthogonal design with two levels of temperature (ambient and +1 °C), three levels of pH (8.1, 7.8, and 7.6), and two levels of boring sponge (Cliona varians, present and absent) to account for differences in sponge attachment and carbonate change for both living and dead coral substrate (Porites furcata). Net coral calcification, net dissolution/bioerosion, coral and sponge survival, sponge attachment, and sponge symbiont health were evaluated. Additionally, we used the empirical data from the experiment to develop a stochastic simulation of carbonate change for small coral clusters (i.e., simulated reefs). Our findings suggest differential impacts of temperature, pH and sponge presence for living and dead corals. Net coral calcification (mg CaCO3  cm(-2)  day(-1) ) was significantly reduced in treatments with increased temperature (+1 °C) and when sponges were present; acidification had no significant effect on coral calcification. Net dissolution of dead coral was primarily driven by pH, regardless of sponge presence or seawater temperature. A reevaluation of the current paradigm of coral carbonate change under future acidification and warming scenarios should include ecologically relevant timescales, species interactions, and community organization to more accurately predict ecosystem-level response to future conditions.

The effects of coastal development on sponge abundance, diversity, and community composition on Jamaican coral reefs.

Over the past decade, development along the northern coast of Jamaica has accelerated, resulting in elevated levels of sedimentation on adjacent reefs. To understand the effects of this development on sponge community dynamics, we conducted surveys at three locations with varying degrees of adjacent coastal development to quantify species richness, abundance and diversity at two depths (8-10 m and 15-18 m). Sediment accumulation rate, total suspended solids and other water quality parameters were also quantified. The sponge community at the location with the least coastal development and anthropogenic influence was often significantly different from the other two locations, and exhibited higher sponge abundance, richness, and diversity. Sponge community composition and size distribution were statistically different among locations. This study provides correlative evidence that coastal development affects aspects of sponge community ecology, although the precise mechanisms are still unclear.