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COMNAP Antarctic Research Fellowship Report 2016/17

Vulnerability of Antarctic bryozoan communities to environmental change (AbcChange)

Candidate: Dr. Blanca Figuerola (Institute of Research in Biodiversity (IRBio), University of Barcelona) Hosts: Dr. Jonathan Stark (Main host; Australian Antarctic Division) and Prof. Damian Gore (Macquarie University)

Vulnerable Marine Ecosystem of the East Antarctica (Photo by AAD).

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Introduction Increases in oceanic temperatures and acidification caused by global environmental change (GEC) are major concerns worldwide [1]. The Southern Ocean (SO) will be one of the first, and most severely, affected regions from ocean acidification (OA) due to its low carbonate saturation levels [3]. Areas of the SO will be undersaturated by 2050 [2] or 2030 when seasonal variation is considered [3]. The saturation horizon (current saturation depth) will become shallower, exposing highly diverse shelf assemblages of marine calcifiers to undersaturated conditions, consequently impacting biomineralization of their skeletons and promoting their dissolution [4]. Some studies have focused on calcified bryozoans from temperate waters [5-6]; less attention has been paid to effects of GEC on bryozoans in Antarctica and particularly East Antarctica [7]. One such area is the Vulnerable Marine Ecosystem (VME) discovered in 2008 on CEAMARC. These communities are characterized by high species richness, in particular habitat-forming bryozoans, hydrocorals and sponges, with many species as yet undescribed [7-9]. Bryozoans are among the most common marine invertebrates that secrete skeletal calcite containing significant amounts of magnesium (Mg), replacing calcium (Ca) ions [10]. Those with more soluble high-Mg calcite skeletons are particularly susceptible to OA [11]. Bryozoans frequently create patch reefs with high biodiversity and many ecosystem services, and consequent economic benefits [12]. Antarctic bryozoans are among the most abundant and diverse phyla and new species continue to be recognised [13-14]. They are often characterized by circumpolar distributions and broad bathymetric ranges [15-16]. Thus, they have potential to help predict overall effects of OA on marine calcifiers across geographical regions [12]. Objectives The aim of the AbcChange project is to improve the understanding of Antarctic bryozoan diversity and skeletal geochemistry so we understand how they will respond to GEC. While the initial purpose of these months was focusing on bryozoan samples from the CEAMARC project, new objectives were established during the research stay allowing the study of different and best represented calcified taxa. Moreover, the percent cover and competitive interactions between Antarctic species were also quantified for a collaborative work. The two main objectives were: (a) to obtain species-level information on Antarctic bryozoan samples from different projects (CEAMARC, Settlement/recruitment and Free ocean CO2 enrichment (AntFOCE) experiments); and (b) to investigate potential influences of environmental and biological factors on skeletal carbonate mineralogy of different marine calcifiers (annelids, bryozoans, cnidarians and echinoderms). Methods Study areas CEAMARC project Samples were collected from East Antarctica using beam trawl during the CEAMARC cruise on the RSV ‘Aurora Australis’ (December 2007 to January 2008). The study area covers part of the region Terre Adélie (Adélie Bank, a large plateau over 200 m in depth at 141−142° E) and George V Land (Commonwealth, Watt and Buchanan Bays, and Mertz Glacier; 142−145° E).

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Settlement/recruitment experiment This study was conducted around Casey Station in the Windmill Islands (66º17'S, 110º 32' E), on the coast of Wilkes Land (East Antarctica) over 9 years. The tiles were deployed in three sites (Brown Bay, O'Brien Bay and Shannon Bay). AntFOCE experiment This experiment was also carried out at Casey Station over 8 weeks in early 2015. The tiles were deployed in 2 acidified chambers (at 0.4 pH below ambient), 2 control chambers (at ambient pH) and 2 open plots (no chamber). Identification of samples Bryozoan samples from the different projects were identified to the lowest taxonomic level possible at the Australian Antarctic Division using a binocular microscopy and a taxonomic reference guide [17]. Species richness Presence/absence data of bryozoan species were compiled for the Settlement/recruitment and AntFOCE experiments at the Australian Antarctic Division. In the case of the Settlement/recruitment experiment, quadrats were placed on the surface of each tile in order to estimate the percent cover of each species. Competitive interactions between species were also quantified. Mineralogy Selected specimens were cleaned carefully of epibionts. From the growing edge of each specimen, a piece (about 3 mm2) was cut and air dried. The pieces were powdered and affixed to single quartz crystal substrates using ethanol. The mineralogy of abundant, widely distributed species (3 replicates from each species and site), of CEAMARC and Settlement/ recruitment projects was assessed using a X-ray diffractometry (XRD) at Macquarie University. XRD was performed on PANalytical X’Pert PRO MPD powder diffractometer equipped with a X'Celerator detector, Bragg Brentano geometry and operating with a Cu Kα (λ = 1.5418 Å) radiation source generated at a voltage of 45 kV and a current of 40 mA. The minerals were identified using a PANalytical's Highscore Plus software v2.2.4, with ICDD PDF2 and PAN-ICSD databases. The wt% MgCO3 in calcite was calculated by measuring the position of the d104 peak, assuming a linear interpolation between CaCO3 and MgCO3 [18-19]. Preliminary results During the 3-month visit, all the planned and extra tasks were successfully achieved. Firstly, more than 2000 bryozoan colonies, belonging to 26 bryozoan species, were identified in the Settlement/recruitment (54 tiles) and the AntFOCE (36 tiles) experiments. Moreover, the percent cover and competitive interactions between Antarctic species of 54 tiles were also quantified (Settlement/recruitment experiment). Secondly, about 800 samples belonging to different taxa were selected to do mineralogical analyses. Finally, a large dataset for biodiversity and mineralogical studies was built. This new data will be valuable for future works as it incorporates mineralogical data of different Antarctic taxa from a greater depth range than most other studies. Therefore, it will provide key insights on the prediction of the overall effects of

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GEC on marine calcifiers and information on threats to highly diverse VMEs from OA. Future work The new postdoc position (Smithsonian Tropical Research Institute, STRI) granted now to the candidate and the regular contact with the researchers from the host institutions will guarantee to finish the work. In particular, the large dataset on mineralogy is being analysed for the best represented taxa (annelids, bryozoans, cnidarians and echinoderms) using a range of software packages (e.g. R vegan). Ecological data from each station will also be compiled to evaluate species’ skeletal mineralogy patterns in relation to environmental parameters. Finally, changes in calcite Mg among geographical and bathymetrical regions will be explored. Outcomes These findings will fill an important gap providing up to date, relevant information on mineralogy of Antarctic benthic communities. The research carried out will also benefit the main host as the research will contribute to the ongoing Antarctic projects (Settlement/recruitment and AntFOCE experiments) of Stark's team. This research will hopefully lead to future collaborations between institutions. Publications AbcChange will lead to multiple peer-reviewed journal articles on diversity and biogeography and GEC. At least, three papers are in preparation: a) one paper will cover the carbonate distribution in benthic communities on the East Antarctic shelf (CEAMARC overview; Figuerola B, Stark J, Gore D, et al. (in prep).), b) a second paper will focus on the variability of Mg-calcite in Antarctic bryozoan skeletons from the East Antarctic shelf (detailed paper of the CEAMARC project; Figuerola B, Stark J, Gore D, et al. (in prep).) and c) a third paper will analyse the skeletal mineralogy patterns in Antarctic marine calcifiers from the East Antarctic shelf (Settlement/ recruitment experiment; Figuerola B, Stark J, Gore D, et al. (in prep).). The findings will contribute to policy development and marine conservation by providing vulnerability assessments regarding the future consequences of OA on marine calcifiers. The award also allowed the participation in two other projects, which involve Antarctic bryozoan competitive interactions and OA effects on this taxon (Settlement/recruitment and AntFOCE experiments, respectively; Stark J et al. (in prep)). Dissemination The home institution, the University of Barcelona, advertised the upcoming visit of the candidate to Tasmania and Sydney on its webpage when she received the COMNAP Fellowship. It is expected that the results will be disseminated via journals and popular science magazines, web pages (ub.edu/irbio) and social networks (Twitter). The research will be a valuable reference material for discussions in SCAR workshops. Personal Impact In terms of her personal development, this fellowship has connected the candidate with international researchers, broadening her scientific network for further opportunities, and has enabled her to diversify her mineralogical skills to become a more competent researcher.

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Budget expenses Expenses provided by the COMNAP fellowship covered the costs of a 3-month stay in Australia, divided in two periods: Jun-July 2017 (Australian Antarctic Division, Tasmania) and Aug-Sept 2017 (Macquarie University, Sydney). No remaining money was left at the end of this period with the budget (7450 USD) being spent in accommodation, subsistence and travel costs. The lab costs were covered by the host institutions. Accommodation (Hobart and Sydney)...............................................................3000 USD Subsistence.........................................................................................................2000 USD Transport (flights, buses, trains and taxis)..........................................................3000 USD Working visa........................................................................................................240 USD Total....................................................................................................................8240 USD Acknowledgements I am extremely grateful to COMNAP Antarctic Research Fellowship for providing this excellent opportunity to continue my research. Special thanks go to my hosts, Dr. Jonathan Stark (Australian Antarctic Division) and Prof. Damian Gore (Macquarie University), for their valuable support and scientific advice throughout the work. I am also thankful to all scientists and staff crew members of the CEAMARC expedition and dive teams of Casey Station for field assistance. References (1) Doney SC, Ruckelshaus M, Duffy JE, Barry JP, Chan F et al (2012) Climate change impacts on marine ecosystems. Ann Rev Mar Sci 4:11–37

(2) Orr JC, Fabry VJ, Aumont O, Bopp L, Doney SC et al (2005) Anthropogenic ocean acidification over the twenty-first century and its impact on calcifying organisms. Nature 437:681–686

(3) McNeil BI, Matear RJ (2008) Southern Ocean Acidification: A Tipping Point at 450-ppm Atmospheric CO2. PNAS 105:18860–18864

(4) Fabry VJ (2008) Ocean science. Marine calcifiers in a high-CO2 ocean. Science 320:1020–1022

(5) Lombardi C, Rodolfo-Metalpa R, Cocito S, Gambi MC, Taylor D (2011) Structural and geochemical alterations in the Mg calcite bryozoan Myriapora truncata under elevated seawater p CO2 simulating ocean acidification. Mar Ecol 32:211–221

(6) Loxton J, Kuklinski P, Najorka J, Jones MS, Porter JS (2014) Variability in the skeletal mineralogy of temperate bryozoans: the relative influence of environmental and biological factors. Mar Ecol Prog Ser 510:45–57 (7) Figuerola B, Kuklinski P, Taylor PD (2015) Depth patterns in Antarctic bryozoan skeletal Mg-calcite: Can they provide an analogue for future environmental changes? Mar Ecol Prog Ser 540:109−120 (8) Stark JS (2000) The distribution and abundance of soft-sediment macrobenthos around Casey Station, East Antarctica. Polar Biol 23:840–850

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(9) Beaman RJ, Harris PT (2005) Bioregionalisation of the George V Shelf, East Antarctica. Cont Shelf Res 25:1657–1691

(10) Bone Y, James NP (1993) Bryozoans as carbonate sediment producers on the cool-water Lacepede Shelf, southern Australia. Sediment Geol 86:247–271

(11) Andersson AJ, Mackenzie FT, Bates NR (2008) Life on the margin: implications of ocean acidification on Mg-calcite, high latitude and cold-water marine calcifiers. Mar Ecol Prog Ser 373:265–273

(12) Wood ACL, Probert PK, Rowden A, Smith AM (2012) Complex habitat generated by marine bryozoans: a review of its distribution, structure, diversity, threats and conservation. Aquat Conserv 22:547−563

(13) Broyer C De, Danis B, & 64 others (2011) How many species in the Southern Ocean? Towards a dynamic inventory of the Antarctic marine species. Deep Res Part II 58:5–17 (14) Figuerola B, Ballesteros M, Avila C (2013) Description of a new species of Reteporella (Bryozoa: Phidoloporidae) from the Weddell Sea (Antarctica) and the possible functional morphology of avicularia. Acta Zool 73:66–73 (15) Barnes DKA, Kuklinski P (2010) Bryozoans of the Weddell Sea continental shelf, slope and abyss: Did marine life colonize the Antarctic shelf from deep water, outlying islands or in situ refugia following glaciations? (2010) J Biogeogr 37:1648–1656

(16) Figuerola B, Monleón-Getino T, Ballesteros M, Avila C (2012) Spatial patterns and diversity of bryozoan communities from the Southern Ocean: South Shetland Islands, Bouvet Island and Eastern Weddell Sea. Syst Biodivers 10:109–123

(17) Hayward PJ (1995) Antarctic cheilostomatous bryozoa. Oxford University Press, Oxford

(18) Chave KE (1952) A solid solution between calcite and dolomite. J Geol 60: 190−192 (19) Mackenzie FT, Bischoff WD, Bishop FC, Loijens M, Schoon-Maker J, Wollast R (1983) Magnesian calcites: low temperature occurrence, solubility and solid-solution behavior. In: Reeder RJ (eds) Carbonates: mineralogy and chemistry, Vol 11. Mineralogical Society of America, Washington, DC, p 97−143