More Like this

1. Composite substrates for coral larval settlement and reef restoration based on natural hydraulic lime and inorganic strontium and magnesium compounds

   https://doi.org/10.1016/j.ecoleng.2024.107236  

   Yus, J; Nixon, EN; Li, J; Noriega_Gimenez, J; Bennett, M-J; Flores, D; Marhaver, KL; Wegley_Kelly, L; Espinosa-Marzal, RM; Wagoner_Johnson, AJ (May 2024, Ecological Engineering)

   NA (Ed.)

   Coral reefs face unprecedented threats from climate change and human activities, making reef restoration increasingly important for the preservation of marine biodiversity and the sustainability of coastal communities. One promising restoration method relies on coral breeding and larval settlement, but this approach requires further innovation to achieve high rates of settlement and survival. In this study, we built on our previous work engineering lime mortar-based coral settlement substrates by investigating three different compositions of a natural hydraulic lime (NHL) base material as well as composite NHL substrates containing alkaline earth metals. These materials were tested with larvae of three reef-building Caribbean coral species: Orbicella faveolata (Mountainous star coral), Diploria labyrinthiformis (Grooved brain coral), and Colpophyllia natans (Boulder brain coral). We found that the base material composition, including its silicate and calcium carbonate (CaCO3) content, as well as the addition of the inorganic additives strontium carbonate (SrCO3), magnesium carbonate (MgCO3), and magnesium sulfate (MgSO4), all influenced coral larval settlement rates. Overall, NHL formulations with lower concentrations of silicate and higher concentrations of calcium, strontium, and magnesium carbonates significantly increased coral settlement. Further, when dissolved ions of magnesium and strontium were added to seawater, both had a significant effect on larval motility, with magnesium promoting settlement and metamorphosis in C. natans larvae, supporting the observation that these additives are also bioactive when incorporated into substrates. Our results demonstrate the potential benefits of incorporating specific inorganic ion additives such as Mg2+ and Sr2+ into substrates to facilitate early coral life history processes including settlement and metamorphosis. Further, our results highlight the importance of optimizing multiple aspects of coral substrate design, including material composition, to promote settlement and survival in coral propagation and reef restoration. 

   more » « less
2. Biomimetic chemical microhabitats enhance coral settlement

   https://doi.org/10.1016/j.tibtech.2025.03.019  

   Kundu, Samapti; Potenti, Simone; Quinlan, Zachary A; Willard, Helena; Chen, Justin; Noritake, Timothy; Levy, Natalie; Karimi, Zahra; Jorissen, Hendrikje; Hancock, Joshua R; et al (May 2025, Trends in Biotechnology)

   Anthropogenic stressors pose substantial threats to the existence of coral reefs. Achieving successful coral recruitment stands as a bottleneck in reef restoration and hybrid reef engineering efforts. Here, we enhance coral settlement through the development of biomimetic microhabitats that replicate the chemical landscape of healthy reefs. We engineered a soft biomaterial, SNAP-X, comprising silica nanoparticles (NPs), biopolymers, and algal exometabolites, to enrich reef microhabitats with bioactive molecules from crustose coralline algae (CCA). Coral settlement was enhanced over 20-fold using SNAP-X-coated substrates compared with uncoated controls. SNAP-X is designed to release chemical signals slowly (>1 month) under natural seawater conditions, and can be rapidly applied to natural reef substrates via photopolymerization, facilitating the light-assisted 3D printing of microengineered habitats. We anticipate that these biomimetic chemical microhabitats will be widely used to augment coral settlement on degraded reefs and to support ecosystem processes on hybrid reefs. 

   more » « less
3. Distinguishing the molecular diversity, nutrient content, and energetic potential of exometabolomes produced by macroalgae and reef-building corals

   https://doi.org/10.1073/pnas.2110283119  

   Wegley_Kelly, Linda; Nelson, Craig E.; Petras, Daniel; Koester, Irina; Quinlan, Zachary A.; Arts, Milou G.I.; Nothias, Louis-Felix; Comstock, Jacqueline; White, Brandie M.; Hopmans, Ellen C.; et al (February 2022, Proceedings of the National Academy of Sciences)

   Metabolites exuded by primary producers comprise a significant fraction of marine dissolved organic matter, a poorly characterized, heterogenous mixture that dictates microbial metabolism and biogeochemical cycling. We present a foundational untargeted molecular analysis of exudates released by coral reef primary producers using liquid chromatography–tandem mass spectrometry to examine compounds produced by two coral species and three types of algae (macroalgae, turfing microalgae, and crustose coralline algae [CCA]) from Mo’orea, French Polynesia. Of 10,568 distinct ion features recovered from reef and mesocosm waters, 1,667 were exuded by producers; the majority (86%) were organism specific, reflecting a clear divide between coral and algal exometabolomes. These data allowed us to examine two tenets of coral reef ecology at the molecular level. First, stoichiometric analyses show a significantly reduced nominal carbon oxidation state of algal exometabolites than coral exometabolites, illustrating one ecological mechanism by which algal phase shifts engender fundamental changes in the biogeochemistry of reef biomes. Second, coral and algal exometabolomes were differentially enriched in organic macronutrients, revealing a mechanism for reef nutrient-recycling. Coral exometabolomes were enriched in diverse sources of nitrogen and phosphorus, including tyrosine derivatives, oleoyl-taurines, and acyl carnitines. Exometabolites of CCA and turf algae were significantly enriched in nitrogen with distinct signals from polyketide macrolactams and alkaloids, respectively. Macroalgal exometabolomes were dominated by nonnitrogenous compounds, including diverse prenol lipids and steroids. This study provides molecular-level insights into biogeochemical cycling on coral reefs and illustrates how changing benthic cover on reefs influences reef water chemistry with implications for microbial metabolism. 

   more » « less
4. Multi‐year evaluation of rearing techniques for three sexually propagated Caribbean corals in a restoration setting

   https://doi.org/10.1111/rec.70039  

   Nixon, Emily_N; Gutting, Alexandra_N; Cook, Sophie; Wegley_Kelly, Linda; Lillis, Ashlee (April 2025, Restoration Ecology)

   In response to declining coral populations worldwide, conservation groups are increasingly applying restoration strategies to bolster abundance and diversity, including sexual propagation of corals. Collection and fertilization of coral gametes as well as larval rearing and settlement have been successful. However, post‐settlement stages remain a bottleneck (80–100% mortality), which makes this technique costly to implement at scale. To address this challenge, we compared the survival and colony size of three sexually propagated Caribbean coral species,Diploria labyrinthiformis,Pseudodiploria strigosa, andOrbicella faveolata, reared at three levels of investment: direct outplant to reef, in situ field nursery rearing, and ex situ aquaculture facility rearing. As part of coral sexual propagation work in St. Croix, United States Virgin Islands, recruits were reared for 1 year before being outplanted to reef plots and were monitored annually for three subsequent years. The cost‐effectiveness of each rearing strategy was calculated at each monitoring time point via coral seeding unit yield and cost per seeding unit. Although survival was low at 4 years (0–1.8%), corals reared in the in situ nursery displayed significantly higher survival and therefore lower cost per seeding unit than the other two investment strategies. These results highlight the benefits of an in situ nursery stage to increase long‐term juvenile survival and cost‐effectiveness. The return on investment of corals reared in the in situ nursery suggests that outplanting sexually propagated corals may be a viable restoration strategy; however, the low proportion of corals surviving at 4 years highlights current limitations when outplanting on degraded reefs. 

   more » « less
5. Soundscape enrichment increases larval settlement rates for the brooding coral Porites astreoides

   https://doi.org/10.1098/rsos.231514  

   Aoki, Nadège; Weiss, Benjamin; Jézéquel, Youenn; Zhang, Weifeng Gordon; Apprill, Amy; Mooney, T Aran (March 2024, Royal Society Open Science)

   The_Royal_Society_Publishing (Ed.)

   Coral reefs, hubs of global biodiversity, are among the world’s most imperilled habitats. Healthy coral reefs are characterized by distinctive soundscapes; these environments are rich with sounds produced by fishes and marine invertebrates. Emerging evidence suggests these sounds can be used as orientation and settlement cues for larvae of reef animals. On degraded reefs, these cues may be reduced or absent, impeding the success of larval settlement, which is an essential process for the maintenance and replenishment of reef populations. Here, in a field-based study, we evaluated the effects of enriching the soundscape of a degraded coral reef to increase coral settlement rates.Porites astreoideslarvae were exposed to reef sounds using a custom solar-powered acoustic playback system.Porites astreoidessettled at significantly higher rates at the acoustically enriched sites, averaging 1.7 times (up to maximum of seven times) more settlement compared with control reef sites without acoustic enrichment. Settlement rates decreased with distance from the speaker but remained higher than control levels at least 30 m from the sound source. These results reveal that acoustic enrichment can facilitate coral larval settlement at reasonable distances, offering a promising new method for scientists, managers and restoration practitioners to rebuild coral reefs. 

   more » « less