New records and observations of macroalgae and associated pathogens from the Falkland Islands, Patagonia and Tierra del Fuego

Subantarctic and Antarctic regions remain little explored with regards to their seaweed diversity. This study is based upon collections in the early 1970s and 2007–2013. It is supported by sequencing COI (mitochondrial cytochrome oxidase I) and reports new records for four species of brown algae Hincksia granulosa, Hincksia sandriana, Myriotrichia clavaeformis, Syringoderma australe), four red algae (Erythrotrichia carnea, Paraglossum salicifolium, Phycodrys antarctica, Plumariopsis eatonii), one green alga (Chaetomorpha aerea) and of the oomycete Anisolpidium ectocarpii. A further four brown algae are reported at genus level and discussed (Cladostephus sp., Colpomenia sp., Dictyota sp., Punctaria sp.). Observations of the biology of three brown algal taxa (Cladothele decaisnei, Geminocarpus geminatus, Halopteris obovata) from the region are also reported here

Seaweed biodiversity in the south-western Antarctic Peninsula: Surveying macroalgal community composition in the Adelaide Island / Marguerite Bay region over a 35-year time span

The diversity of seaweed species of the south-western Antarctic Peninsula region is poorly studied, contrasting with the substantial knowledge available for the northern parts of the Peninsula. However, this is a key region affected by contemporary climate change. Significant consequences of this change include sea ice recession, increased iceberg scouring and increased inputs of glacial melt water, all of which can have major impacts on benthic communities. We present a baseline seaweed species checklist for the southern Adelaide Island and northern Marguerite Bay region, combining data obtained during a small number of surveys completed in 1973–1975 and a 6-week intensive diving-based field campaign in 2010–2011. Overall, with a total of 41 macroalgal species recorded (7 brown, 27 red, 6 green, 1 chrysophyte), the region is species-poor compared to the north of the Antarctic Peninsula, and even more so in comparison with the sub-Antarctic. The key canopy-forming species is Desmarestia menziesii, which is abundant in Antarctic Peninsula waters, but lacking in the sub-Antarctic. Himantothallus grandifolius, which is a common species further north in the Antarctic phytobenthos, was absent in our recent collections. This paper also reports the first record of Aplanochytrium sp. (Labyrinthulomycetes) from this part of Antarctica and in association with Elachista sp

Dictyota falklandica sp. nov. (Dictyotales, Phaeophyceae) from the Falkland Islands and southernmost South America

ACKNOWLEDGEMENTS Special thanks to Paul Brickle (South Atlantic Environmental Research Institute) for hosting our expedition. FUNDING We thank the Shackleton Scholarship Fund (for travel grants to FCK and AFP to the Falkland Islands), the UK Natural Environment Research Council (program Oceans 2025 – WP 4.5 and grant NE/D521522/1), and the TOTAL Foundation (Project “Diversity of brown algae in the Eastern Mediterranean”). This work also received support from the Marine Alliance for Science and Technology for Scotland pooling initiative. MASTS is funded by the Scottish Funding Council (grant reference HR09011) and contributing institutions. ECM acknowledges support by the Chilean Millennium Initiative (NC120030) grant. This work makes use of resources and facilities provided by Ghent University as part of the Belgian contribution to EMBRC-ERIC (FWO GOH3817N).Peer reviewedPublisher PD

Arctic marine phytobenthos of northern Baffin Island

This project was supported by SAMS and NFSD core funding (Oceans 2025 WP 4.5 from the UK Natural Environment Research Council), the European Commission (ASSEMBLE, grant agreement no. 227799), and the TOTAL Foundation (Paris; Project “Macroalgal and oomycete benthic diversity in the Canadian Marine Arctic”). This work also received funding from the MASTS pooling initiative (The Marine Alliance for Science and Technology for Scotland) and their support is gratefully acknowledged. MASTS is funded by the Scottish Funding Council (grant reference HR09011) and contributing institutions. We also would like to thank Laura Grenville-Briggs (KTH, Stockholm) for help with bioinformatics analyses as well as Cindy Grant and Philippe Archambault (University of Quebec, Rimouski) for help with preparing the map of the study area (Fig. 1).Peer reviewedPublisher PD

Marine benthic algal flora of Ascension Island, South Atlantic

ACKNOWLEDGEMENTS We are grateful to Nick John, Jimmy Young and Caroline Yon (all in Ascension Island) for sampling assistance. We would also like to thank Konstantinos Kondylis for help with the DNA amplification of macroalgal isolates. We are grateful to the Shallow Marine Surveys Group and the South Atlantic Environmental Research Institute for organizing the expedition. We are also very grateful to the Ascension Island Government, the members of staff at the Conservation Centre and Ascension Island Dive Club for their cooperation, accommodation and hospitality. Finally we are grateful to British Forces South Atlantic Islands for their logistic support. FINANCIAL SUPPORT The MASTS pooling initiative (Marine Alliance for Science and Technology for Scotland, funded by the Scottish Funding Council and contributing institutions; grant reference HR09011) is gratefully acknowledged for supporting F.C.K. The funding for this work came from a grant to the Shallow Marine Surveys Group from the Darwin Initiative (EIDCF012).Peer reviewedPostprin