Polar Biology https://doi.org/10.1007/s00300-018-2292-7 ORIGINAL PAPER A biodiversity survey of scavenging amphipods in a proposed marine protected area: the Filchner area in the Weddell Sea, Antarctica Charlotte Havermans1,2 · Meike Anna Seefeldt2,3 · Christoph Held2 Received: 17 October 2017 / Revised: 23 February 2018 / Accepted: 24 February 2018 © Springer-Verlag GmbH Germany, part of Springer Nature 2018 Abstract An integrative inventory of the amphipod scavenging fauna (Lysianassoidea), combining morphological identifcations with DNA barcoding, is provided here for the Filchner area situated in the south-eastern Weddell Sea. Over 4400 lysianassoids were investigated for species richness and relative abundances, covering 20 diferent stations and using diferent sampling devices, including the southernmost baited traps deployed so far (76°S). High species richness was observed: 29 morphos- pecies of which 5 were new to science. Molecular species delimitation methods were carried out with 109 cytochrome c oxidase I gene (COI) sequences obtained during this study as well as sequences from specimens sampled in other Antarctic regions. These distance-based analyses (trees and the Automatic Barcode Gap Discovery method) indicated the presence of 42 lineages; for 4 species, several (cryptic) lineages were found. More than 96% of the lysianassoids collected with baited traps belonged to the species Orchomenella pinguides s. l. The diversity of the amphipod scavenger guild in this ice-bound ecosystem of the Weddell Sea is discussed in the light of bottom–up selective forces. In this southernmost part of the Weddell Sea, harbouring spawning and nursery grounds for silverfsh and icefshes, abundant fsh and mammalian food falls are likely to represent the major food for scavengers. Finally, the importance of biodiversity surveys in the context of the establishment of a marine protected area in this region (Weddell Sea MPA) is highlighted and how future studies can contribute to a better understanding the ecological role of scavengers in this system is discussed. Keywords Amphipoda · Lysianassoidea · Barcoding · COI gene · Taxonomy · Carrion-feeder · Food falls Introduction Electronic supplementary material The online version of this The exploitation of natural resources as well as rapid article (https​://doi.org/10.1007/s0030​0-018-2292-7) contains environmental changes, with their cascading conse- supplementary material, which is available to authorized users. quences such as community and regime shifts, are known to have major impacts on the stability of ecosystems and Charlotte Havermans and Meike Anna Seefeldt have contributed equally to this work. thus ecosystem function (Scheffer and Carpenter 2003; Worm et al. 2006; Harley 2011; Bellard et al. 2012). The * Charlotte Havermans resilience of an ecosystem is dependent on its response [email protected] to the loss and disturbances of critical key species and * Meike Anna Seefeldt communities. The prevention of this accelerating loss of [email protected] biodiversity in both coastal (e.g., Jackson et al. 2001) and 1 Marine Zoology, BreMarE Bremen Marine Ecology, open-ocean ecosystems (e.g., Worm et al. 2005), as well Universität Bremen, PO Box 330 440, 28334 Bremen, as ecosystem functioning and services (e.g., see Worm Germany et al. 2006) is one of major aims of global conservation 2 Alfred-Wegener-Institut Helmholtz-Zentrum für Polar- und organisations like the International Union for Conser- Meeresforschung, Am Handelshafen 12, 27568 Bremerhaven, vation for Nature (IUCN). One of the goals within the Germany Aichi biodiversity targets of the convention on biologi- 3 Department of Animal Ecology, Evolution and Biodiversity, cal diversity (CBD), which was later reaffirmed as Goal Ruhr-Universität Bochum, Universitätsstraße 150, 14 within the United Nations sustainable development 44801 Bochum, Germany Vol.:(0123456789)1 3 Polar Biology goals (UNSDG), is to protect 10% of the worlds coastal the north-eastern Weddell Sea continental shelf (Grifths and marine areas (CBD 2010; UNSDG 2015). The estab- et al. 2010), and until recently, only a handful of stations has lishment of marine protected areas (MPAs) is considered been quantitatively sampled in the Filchner Trench (Knust a suitable tool that designates certain marine areas of and Schröder 2014). specific economic, biodiversity, and species conserva- Situated in the south-eastern Weddell Sea, the Filchner tion interest (CBD 2004). MPAs benefit from measures area is considered to be a key oceanographic region, char- preventing the exploitation of marine resources, e.g., by acterized by a complex system of formation and mixing of implementing a sustainable fishery or fishing prohibition water masses with various in- and outfows (Darelius et al. in no-take areas as well as tourism management. While 2014). The Filchner Trough, intersecting the continental nearly every coastal country has implemented an MPA- shelf break at 33°W, is bounded by the Filchner-Ronne like structure (Agardy et al. 2003), the Southern Ocean Ice Shelf, the world’s largest ice shelf by volume (Fox and has been long time neglected in this regard despite its Cooper 1994; Grosfeld et al. 2001). In this region, strong pristine character and large area. The Southern Ocean sea-ice formation creates brine rejection and dense saline (sensu lato, i.e., including sub-Antarctic areas sensu shelf water production (Haid and Timmermann 2013), whilst De Broyer et al. 2014, hereafter SO) harbours complex melting and freezing events at the base of the ice shelf are ecosystems and communities which can vary over small responsible for the production of ice shelf water, a precur- geographical scales (Gutt et al. 2013). Its marine fauna is sor of the Antarctic Bottom Water (Foldvik et al. 2004). rich in species, particularly in the benthos, with many rep- Hence, this area is of major importance for the global ocean resentatives in groups such as crustaceans, polychaetes, circulation and ventilation of the world’s abyss (Foldvik sponges, gastropods, and bryozoans (e.g., Arntz et al. et al. 2004). Changes in sea-ice conditions, warming surface 1994; Clarke 2008). Its unique features, e.g., geographic waters (Grosfeld and Gerdes 1998), and calving icebergs and climatic isolation, low and stable temperatures, and (Grosfeld et al. 2001) may have severe consequences for the an extreme seasonality, are thought to have contributed Filchner-Ronne ice shelf and the production of bottom water, to the evolution of a high endemicity, adaptive radiations, which are, however, difcult to predict due to the complex- and species flocks observed in several taxa (reviewed in ity of the regionally heterogeneous hydrographic conditions Chenuil et al. 2018). (Darelius et al. 2014) and the interplay between winds, eddy The Antarctic treaty signatory powers, through the con- processes, hydrographic forcing from precipitation, sea ice, vention for the conservation of Antarctic marine living and ice shelf melting (Hellmer et al. 2017). Nevertheless, resources (CCAMLR), have been working on the assign- certain simulations with IPCC-simulated scenarios, based ment of a network of MPAs across the SO. To do so, they on coupled ice-ocean models, project an increase in basal have agreed on a system, dividing the SO into nine marine melting and ice shelf thinning with a tipping point where large-scale planning domains covering convention areas in these changes will be irreversible with strong implications which both scientifc research as well as MPAs are planned on the Antarctic ice sheet (Hellmer et al. 2017). and considered (CCAMLR 2005, 2011, 2012). The South In addition, from a faunal point of view, the Filchner area Orkney Islands Southern Shelf MPA was the frst no-take has been referred to as a hotspot, both in terms of diversity area in the SO designated by CCAMLR (2009). The world’s and abundance of certain taxa, mainly fsh and marine mam- largest MPA, situated in the Ross Sea, was recently resolved mals (Knust and Schröder 2014). In the area, the outfow in October 2016 and will be taken into force in December of ice shelf water mixes with the oceanic deep waters of 2017 with 72% of its assigned area planned as a no-take the Weddell Gyre circulation, resulting in physical fronts. area (CCAMLR 2016). Since 2011, an MPA for the East This is believed to be the primary cause of this area being Antarctic domain is under negotiation, being proposed by a biological hotspot, where upper and intermediate trophic Australia and the European Union (CCAMLR 2011). The levels are maximized (Bornemann et al. 2014). This complex European Union recently submitted a further proposal, con- regional hydrography infuences the downward fux of sea- ceptualised by Germany, requesting the Weddell Sea as a ice algae, phytoplankton, and derived organic matter (Auel MPA covering eco-regions with characteristic biodiversity et al. 2014). Both meso- and macro-zooplankton appear to and biogeographic patterns (Teschke et al. 2016). Besides be particularly diverse in the Filchner Trough but compara- being a region of international research focus over many tively lower in biomass than in the more northern region decades, our current knowledge of the Weddell Sea environ- of the eastern Weddell Sea (Boysen-Ennen 1987; Boysen- ment and the ecology of its key species are rather patchy. Ennen and Piatkowski 1988; Auel et al. 2014). Conversely, This particularly holds true for the southernmost eastern nekton biomass and production have been reported to be shelf region: the Filchner area, in which six special protec- high in the southern part of the Weddell Sea, largely due tion zones are proposed inside the planned MPA (Teschke to the high abundances of the Antarctic silverfsh Pleura- et al. 2016). This area has been undersampled compared to gramma antarcticum Boulenger, 1902 (Hubold 1984), which 1 3 Polar Biology are linked with high foraging occurrences of marine mam- 1 knot for 10–30 min, whereas the bottom trawl (BT) was mals such as Weddell seals (Plötz et al. 2001). Hence, a equipped with 40-mm mesh in the cod end, and was towed at high number of larger carcasses of fsh and mammals are 3 knots for 30 min.