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Communities are increasingly harnessing the coastal protection functions of marshes and other coastal ecosystems within built infrastructure, developing nature-based designs to stabilize coastlines. These “living shorelines” often include planting ecosystem-engineering plants, which have traits that attenuate waves and facilitate sediment accretion while limiting erosion. However, failure is common during plant establishment, requiring interdisciplinary approaches to inform planting designs that enhance short-term sediment stability. Here we combine hydrodynamic modelling with mesocosm experiments to assess different planting approaches for the marsh grass Spartina alterniflora. The model, parameterized with traits measured in the experiments, showed that random arrangement of plants outperformed regular arrangements, reducing areas of high flow velocities and increasing tortuosity, facilitating sediment stability. Furthermore, wide-diameter Spartina clumps with increased biomass reduced flow better than small-diameter clumps, even when the area occupied by the vegetation site-wide is identical. Our experiments revealed multiple factors that influence the diameter and biomass of Spartina clumps, including plant source, sediment characteristics, and spatial arrangement of propagules. While some sources performed better than others, their relative performance varied with time and environment, suggesting that practitioners plant multiple sources to ensure incorporating high-performers in variable and often unexamined planting environments. Furthermore, clumping propagules during planting best generated the large, dense clumps that facilitate sediment stability. 

Abstract A working group from the Global Library of Underwater Biological Sounds effort collaborated with the World Register of Marine Species (WoRMS) to create an inventory of species confirmed or expected to produce sound underwater. We used several existing inventories and additional literature searches to compile a dataset categorizing scientific knowledge of sonifery for 33,462 species and subspecies across marine mammals, other tetrapods, fishes, and invertebrates. We found 729 species documented as producing active and/or passive sounds under natural conditions, with another 21,911 species deemed likely to produce sounds based on evaluated taxonomic relationships. The dataset is available on both figshare and WoRMS where it can be regularly updated as new information becomes available. The data can also be integrated with other databases (e.g., SeaLifeBase, Global Biodiversity Information Facility) to advance future research on the distribution, evolution, ecology, management, and conservation of underwater soniferous species worldwide. 

The organic carbon (Corg) stored in seagrass meadows is globally significant and could be relevant in strategies to mitigate increasing CO2 concentration in the atmosphere. Most of that stored Corg is in the soils that underlie the seagrasses. We explored how seagrass and soil characteristics vary among seagrass meadows across the geographic range of turtlegrass (Thalassia testudinum) with a goal of illuminating the processes controlling soil organic carbon (Corg) storage spanning 23° of latitude. Seagrass abundance (percent cover, biomass, and canopy height) varied by over an order of magnitude across sites, and we found high variability in soil characteristics, with Corg ranging from 0.08 to 12.59% dry weight. Seagrass abundance was a good predictor of the Corg stocks in surficial soils, and the relative importance of seagrass-derived soil Corg increased as abundance increased. These relationships suggest that first-order estimates of surficial soil Corg stocks can be made by measuring seagrass abundance and applying a linear transfer function. The relative availability of the nutrients N and P to support plant growth was also correlated with soil Corg stocks. Stocks were lower at N-limited sites than at P-limited ones, but the importance of seagrass-derived organic matter to soil Corg stocks was not a function of nutrient limitation status. This finding seemed at odds with our observation that labile standard substrates decomposed more slowly at N-limited than at P-limited sites, since even though decomposition rates were 55% lower at N-limited sites, less Corg was accumulating in the soils. The dependence of Corg stocks and decomposition rates on nutrient availability suggests that eutrophication is likely to exert a strong influence on carbon storage in seagrass meadows. 

The urgency for remote, reliable and scalable biodiversity monitoring amidst mounting human pressures on ecosystems has sparked worldwide interest in Passive Acoustic Monitoring (PAM), which can track life underwater and on land. However, we lack a unified methodology to report this sampling effort and a comprehensive overview of PAM coverage to gauge its potential as a global research and monitoring tool. To address this gap, we created the Worldwide Soundscapes project, a collaborative network and growing database comprising metadata from 416 datasets across all realms (terrestrial, marine, freshwater and subterranean).