Both Eric and Emma from UoP – University of Portsmouth (RaNTrans project leader) were in attendance at the British Phycological Society Winter Meeting 2023, and presented on the theme of “Understanding and using algae”

Eric Harris-Scott recently worked on both oysters and seaweed work packages for RaNTrans and is very knowledgeable to present on – “Assessing the impact of deployment location on sugar kelp (Saccharina latissima) mortality, growth, and other conditions as well as ecosystem provision”.
He echoed that kelps are one of the fastest growing organisms in the world, thriving on nutrients suspended in the waters around them; when cultivated at scale, can remove large quantities of nitrogen (N) and phosphorous (P) from coastal ecosystems. Marine nutrient pollution is an increasing issue around the world with climate change and coastal urbanisation making it harder to curb growing eutrophication. The majority of wastewater produced on land by anthropogenic activities is discharged, with varying levels of treatment, into the coastal environment from point/non-point sources.

Through the deployment of kelp longlines in three locations in the NE Atlantic, with varying environmental conditions and nutrient inputs, this research aims to assess the ability of sugar kelp to be utilised as a coastal management tool in eutrophic areas. Monitoring growth rate and measuring the amounts of N and P in kelp biomass across sites to determine the environmental variables including water temperature, turbidity, salinity and dissolved oxygen that are the key drivers of change in the assimilation rates of N and P. Stable isotope analysis of in the kelp biomass will provide information on the provenance of assimilated N and inform policy decisions to identify and combat directly point and non-point N sources

Emma A Ward, is working on a separate project at UoP and was able to provide carbon sequestration comparison values for seaweed and seagrass in her presentation – “Seagrass distribution and spatial variation in quality – seascape context and influences on carbon storage?”
Emma emphasised the importance of producing accurate estimates of habitat extent and quality is a prerequisite to determining their ecosystem services (ES) provision, but often variation in quality exists within a habitat, likely influencing ES provision.

Seagrass meadows have been cited as important habitats for ES including carbon sequestration, nutrient remediation, and coastal protection (sediment stabilisation). To provide accurate data on seagrass ES and functionality, mapping needs to distinguish both the area and quality of habitat. This study maps intertidal seagrass (species composition and density) and algal mat spatial distribution, as the proliferation of algal mat can reduce light penetration in the water column reducing habitat suitability for seagrass. Sediment cores were collected across several habitat quality classifications from the spatial habitat quality maps, to focus on sedimentary carbon and nitrogen retention within these habitats. The spatial mapping highlights several important factors: i) demonstrable edge effects; ii) high spatial variation in seagrass density are prevalent characteristics, which act as indicators of habitat quality; iii) green macroalgal mat negatively influences seagrass distribution. Therefore, variation within the seagrass seascape (species composition and density), alongside adjacent habitat types (algal mat) within the wider seascape should be considered when assessing ecosystem services provision.

@bps_algae

#BPS23

Our work continues in 2023!

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