Unvegetated, intertidal sandflats play a critical role in estuarine carbon and nutrient dynamics. However, these ecosystems are under increasing threat from anthropogenic stressors, especially nitrogen enrichment. While research in this area typically focuses on sediment-water exchanges of carbon and nutrients during tidal inundation, there remain significant gaps in our understanding of GHG (Greenhouse Gas) fluxes during tidal emergence. Here we use in situ benthic chambers to quantify GHG fluxes during tidal emergence and investigate the impact of nitrogen enrichment on these fluxes. Our results demonstrate significant differences in magnitude and direction of GHG fluxes between emerged and submerged flats, demonstrating the importance of considering tidal state when estimating GHG emissions from intertidal flats. These responses were related to differences in microphytobenthic and macrofaunal activity, illustrating the important role of ecology in mediating fluxes from intertidal flats. Our results further demonstrate that nitrogen enrichment of 600 gN m −2 was associated with, on average, a 1.65x increase in CO 2 uptake under light (photosynthetically active) conditions and a 1.35x increase in co 2 emission under dark conditions, a 3.8x increase in CH 4 emission and a 15x increase in n 2 O emission overall. This is particularly significant given the large area intertidal flats cover globally, and their increasing exposure to anthropogenic stressors.

Life-history traits and the ecology of the family Pentacerotidae are known for only a fraction of the 13 species distributed worldwide. The Giant Boarfish (Paristiopterus labiosus) is known for its increasing recreational fishery and for undergoing spawning aggregations in Australasian waters but the biological characteristics remain scarce. Here, we report the capture of a large P. labiosus (962mm total length and 9.2kg total weight), close to the reported maximum size of 910mm total length, from New Zealand waters and its age estimation. An estimated age of 36 years, based on counts of opaque zones in thin otolith sections, provides important information on the potential lifespan of the species, an important step forward to better understand its life history.