An integrated compilation of data sources for the development of a marine protected area in the Weddell Sea

The Southern Ocean may contribute a considerable part to the proposed global network of Marine Protected Areas (MPAs) that should cover about 10% of the world oceans in 2020. In the Antarctic, the Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR) is responsible for this task, and currently Germany leads a corresponding scientific evaluation of the wider Weddell Sea region. Compared 20 to other marine regions within the Southern Ocean, the Weddell Sea is exceptionally well investigated. A tremendous amount of data and information has been produced over the last four decades. Here, we give a systematic overview of all data sources collected in the context of the Weddell Sea MPA planning process. The compilation of data sources comprises data produced by scientists / institutions from more than twenty countries and were either available within our institutes, downloaded via data portals, or transcribed from the literature. It 25 is the first compilation for this area that includes abiotic data, such as bathymetry and sea ice, and ecological data from zooplankton, zoobenthos, fish, birds and marine mammals. All data layer products based on this huge compilation of environmental and ecological data are available from the data publisher PANGAEA via the six persistent identifiers at https://doi.org/10.1594/PANGAEA.899595 (Pehlke and Teschke, 2019), https://doi.org/10.1594/PANGAEA.899667 (Teschke et al., 2019a), https://doi.org/10.1594/PANGAEA.899645 30 (Teschke et al., 2019b), https://doi.org/10.1594/PANGAEA.899591 (Teschke et al., 2019c), https://doi.org/10.1594/PANGAEA.899520 (Pehlke et al., 2019a) and https://doi.org/10.1594/PANGAEA.899619 (Pehlke et al., 2019b). This compilation of data sources with the final data layer products will serve future research and monitoring well beyond the current MPA development process. 35


Introduction
Marine protected areas (MPAs) have experienced a significant increase in number and coverage at a global scale during recent decades (e.g. Mora and Sale, 2011;McDermott et al., 2018;UNEP-WCMC and IUCN, 2019). The number of MPAs has increased almost 1.5 times since the 1990s and the total area protected is currently almost 30 million km 2 . At the United Nations World Summit on Sustainable Development in 2002 the international community of states reached an agreement about the establishment of a representative network of MPAs for the purpose of long-term conservation of marine biodiversity by 2012 (A/CONF.199/20, 2002). The adopted "strategic plan for biodiversity 2011-2020" of the Convention on Biological Diversity aims for the conservation of at least 10 % of coastal and offshore marine areas by 2020 based on a MPA network (CBD, 2010). The Southern Ocean may contribute a considerable proportion of this MPA network due to its size, and the uniqueness of the Antarctic environment renders its conservation the more urgent.
The Weddell Sea represents the southerly part of the Atlantic Sector of the Southern Ocean. About a quarter of the Weddell Sea's entire marine area covers the continental shelf along the eastern contour of the Antarctic Peninsula and the Antarctic continent up to 20 • E as a heuristically chosen nontopographic delineation. The Weddell Sea is deserving of protection in multiple respects. On the one hand, all arguments for the conservation of the Southern Ocean hold true for the Weddell Sea as well; i.e. it is an extreme environment that is mostly dominated by the seasonal dynamic of the sea ice and has an excellently adapted biota. The biodiversity is -particularly in the benthos -very high (e.g. Brey et al., 1994;Brandt et al., 2007), and there is a significant number of endemic species, i.e. unique to the Antarctic or even to the Weddell Sea (e.g. Arntz et al., 1994;Clarke and Johnston, 2003;Linse et al., 2006). Moreover, the Weddell Sea plays an important role for seabirds, penguins and marine mammals. Almost one-third of the entire population of emperor penguins (Fretwell et al., 2012) and a major part of the population of crabeater seals (cf. Bester and Odendaal, 2000;Southwell et al., 2012;Gurarie et al., 2017a, b) apparently are found in the Weddell Sea. Sponge associations that are comparable to tropical reef systems in terms of their structural and functional complexity occur along the eastern Weddell Sea shelf (Barthel and Gutt, 1992), and on the broad shelf in the southern Weddell Sea a special benthic community -adapted to very cold water temperatures -seems to be resident (Teschke et al., 2016).
The Weddell Sea is -despite being one of the most remote and inaccessible places on Earth -relatively well investigated compared to other Antarctic regions. For approximately 30 years the Weddell Sea has been the geographical focus area of German Antarctic research. In addition, there are manifold research activities of other nations. Consequently, we were able to compile a tremendous amount of en-vironmental and ecological data to support the development of a Weddell Sea MPA (WSMPA) under the Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR). Here, we present a systematic overview of all environmental and ecological data sources collected for the development of a WSMPA and provide data layer products that are based on this data compilation.

Study site
The WSMPA Planning Area in which we acquired the environmental and ecological data is located between the Antarctic Peninsula and 20 • E (Fig. 1). The northern border is at 64 • S and the continental margin forms the southern border. This area is defined by CCAMLR's MPA Planning Domains in the CCAMLR Convention Area (SC-CAMLR-XXX, 2011) and by aiming at a bio-geographically homogeneous area, particularly on the shelf (Teschke et al., 2016). In addition to the WSMPA Planning Area (approx. 4.2 million km 2 in size) we compiled data for a 200 km wide buffer area near the Antarctic Peninsula, which is part of an MPA initiative led by Argentina and Chile (CCAMLR-XXXVII/31, 2018). This buffer zone is adjacent to the northern border of the WSMPA Planning Area and has eastern and western boundaries at 30 and 60 • W, respectively. Some data (e.g. seal tracking data) extend beyond the WSMPA Planning Area (plus buffer) and originate from adjacent regions of the Weddell Sea, such as the Bellinghausen Sea along the western side of the Antarctic Peninsula.

Data compilation
All raw data sets of environmental and ecological parameters collected by the end of 2016 and further processed as part of the WSMPA planning process are systematically described, and the primary reference is mentioned, such as the data portal from which the data are freely available or the website of the institute or organisation from which the data can be requested (see Tables 1 and 2; see all data records in Figs. 2 and S1 in the Supplement). For each individual raw data set in Tables 1 and 2, the accessibility status is indicated; i.e. it is immediately clear which data sets are directly freely available and which data sets must first be requested.
In addition, we offer data layer products that we developed on the basis of the raw data sets whose sources are described here. The methods used to process and analyse the data and to develop each data layer are described in detail in the Supplement. All data layer products with a metadata description are freely available from the data publisher PANGAEA via the six persistent iden- Data collection of environmental parameters compiled for the development of a marine protected area (MPA) in the wider Weddell Sea (Antarctica). For each raw data set, the name of the data source, the primary reference, such as the data portal or website on which the data are available, and examples of publications that have used the respective raw data set are listed. In addition, DOI links are provided to the final WSMPA data layer products where the respective environmental raw data sets have been mapped (as in the pelagic regionalisation approach) or used as explanatory variables for the development of species distribution data layers.   Tables 1 and 2). The data layers are available either as ArcMap packages (as a .mxd file, containing a map document with all associated files) or as individual GIS files for those who use GIS software other than the ESRI software (ArcMap). The shape and raster files, all of which have the same spheroid (WGS 1984, EPSG 4326) and projection (South Pole Lambert Azimuthal Equal Area, EPSG 102020), were processed in such a way that they can be easily used for the analysis of MPA scenarios or other geostatistical analyses in the Weddell Sea without direct access to the underlying raw data. For example, the shape and raster files could be stacked to identify hotspots and cold spots of biodiversity, or certain layers could be used as explanatory variables in species distribution models.

Environmental data 2.3.1 IBCSO data
The bathymetric data used in the context of the WSMPA planning initiative originate from the first regional digital bathymetric model (DBM) established in the International Bathymetric Chart of the Southern Ocean (IBCSO) Version 1.0 programme (data request: April 2013) ( Table 1; Fig. 3a). This chart model is based upon bathymetric data of different origins, such as multi-beam and single-beam data; digitised depths from nautical charts; and predicted bathymetry from many hydrographic offices, scientific institutions, and data centres. The IBCSO Version 1.0 DBM has a horizontal resolution of 500 m × 500 m and a vertical resolution of 1 m based on a polar stereographic projection with true scale at 65 • referenced to the WGS84 ellipsoid (Arndt et al., 2013a, b).

AMSR-E sea ice maps
Daily high-resolution sea ice maps of the Antarctic Ocean are provided by the PHAROS group (PHysical Analysis of RemOte Sensing images) at the Institute of Environmental Physics, University of Bremen, Germany. The sea ice raster maps, which were used in the context of the WSMPA planning initiative, are derived from satellite observations of daily sea ice concentration by the Advanced Microwave Scanning Radiometer -Earth Observing System (AMSR-EOS) instrument on board the Aqua satellite. Daily AMSR-E sea ice maps (2013) (June 2002-October 2011) were downloaded from IUP, University of Bremen (data request: 18 December 2013) (see Table 1; Fig. 3b). The ARTIST Sea Ice (ASI) concentration algorithm was used with a spatial resolution of 6.25 km × 6.25 km (Spreen et al., 2008) and a polar stereographic projection (EPSG: 3976).

FESOM data
Monthly mean values of seawater temperature, salinity and current velocity from 1990 to 2009 were derived from the Finite Element Sea Ice -Ocean Model (FESOM) ( Table 1; Fig. 3c, d). The model run was initialised on 1 January 1980 with hydrographic data from the Polar Science Center Hydrographic Climatology (Steele et al., 2001), and forced with NCEP daily atmospheric re-analysis data (Kalnay et al., 1996) for 1980 to 2009. For more information on FESOM and the atmospheric-forcing data sets, see, e.g. Timmermann et al. (2009) and Haid and Timmermann (2013), respectively. The FESOM raster has a resolution of 0.18 • (x) × 0.05 • (y); in the vertical, two z levels (i.e. sea surface and sea bottom) are used. The raster is based on the WGS84 geographic coordinate system (EPSG: 4326).
IBCSO data, AMSR-E sea ice maps and FESOM data were used in a pelagic regionalisation analysis of the Weddell Sea. The respective data layer products are avail- Table 2.
Data collection of ecological parameters compiled for the development of a marine protected area (MPA) in the wider Weddell Sea (Antarctica). For each raw data set, the name of the data source, the primary reference, such as the data portal or website on which the data are available, and the respective cruise reports and/or examples of publications that have used the respective raw data set are listed. In addition, DOI links to the final WSMPA data layer products are provided, including the respective raw data sets.   (2008) Siegel (2012) https://doi.org/10.1594/ PANGAEA.899667  Zoobenthos   Drescher et al. (1983) Kohnen (1984) Schnack-Schiel (1987) Fütterer (1988) Arntz and Gutt (1999) Arntz and Brey (2001) Voß (1988) https://doi.org/10.1594/ PANGAEA.899645  Echinoderms -Ophiuroids (abundances)

SeaWiFS data
Near-surface chlorophyll a concentration values stem from the Sea-Viewing Wide Field-of-View Sensor (SeaWiFS) measurements on board the OrbView-2 (formerly SeaStar) spacecraft (Table 1). The monthly aggregated data (1997 to 2010) were downloaded as level 3 standard mapped images (L3SMI) with a spatial resolution of 9 km × 9 km (data request: 9 September 2014).

WOA13 data
Data on dissolved oxygen, phosphate and nitrate were obtained from the World Ocean Atlas 2013 version 2 (WOA13 V2) (Garcia et al., 2014a, b) (Table 1). The data (1955 to 2012) were downloaded as monthly statistical means with a horizontal resolution of 1 • (x) × 1 • (y) and 57 and 37 vertical (z) levels between 0 to 1500 and 0 to 500 m for dissolved oxygen and phosphate or nitrate, respectively. The data requests were made on 11 July 2013 (dissolved oxygen), 17 July 2013 (nitrate) and 18 July 2013 (phosphate), respectively.

Data on chemical sediment components
A data compilation of total organic carbon content and calcium carbonate and silica in surface sediments was downloaded from the data archive PANGAEA (Seiter et al., 2004a, b, c, and references therein) (see Table 1). Data on biogenic silica of the sediment surface were obtained from PAN-GAEA as well (Geibert et al., 2005b). The data described under Sect. 2.3.4 to 2.3.6 were used as explanatory variables in the Antarctic krill species distribution model (SDM) (SeaWiFS, WOA13, chemical sediment components) and in the demersal fish SDM (WOA13, chemical sediment components). The SDMs are described in detail in the Supplement and the PANGAEA link to the respective data layer products (including file names) is given in the corresponding subsection under Sect. 2.4.

Ecological data
In the following, we describe the sources of raw data sets used in the WSMPA planning process and indicate which data layer product was developed on the basis of which raw data sets. In addition, the methods for processing and analysing the data and for developing each data layer are described in detail in the Supplement.
All of these data were used in a species distribution model (SDM) of adult Antarctic krill and ultimately led to a data layer product showing habitat suitability for adult Antarctic krill in the WSMPA Planning Area (see https://doi.org/10.1594/PANGAEA.899667, ; "Adult Antarctic krill, Euphausia superba -habitat suitability prediction").
All of the data on Antarctic krill larvae were used for an interpolation approach and led to a map of the interpolated abundances of krill larvae in the WSMPA Planning Area (see https://doi.org/10.1594/PANGAEA.899667, ; "Antarctic krill larvae, Euphausia superba -interpolated abundance").

Ice krill
Abundance data on adult ice krill (Euphausia crystallorophias) originate from pelagic trawl surveys during  Table 2).
All data on E. superba and E. crystallorophias that were used, in addition to KRILLBASE and the CCAMLR database, are stored in the data warehouse of the Thünen Institute of Sea Fisheries (https://www.thuenen.de/de/sf, last access: 9 March 2020) and can be requested on demand.

Zoobenthos
Sponges Abundance data and semi-quantitative data on sponges (higher taxonomic groups) that were compiled in the context of the WSMPA planning initiative, originate from zoobenthos data sets. The abundance data (Gerdes, 2014a-p) and the semi-quantitative data set (Teschke and Brey, 2020) are publicly available via PANGAEA (see Table 2).

Echinoderms
The compiled data set on echinoderms consists of presenceabsence data on a species level for asteroids and abundance data on ophiuroid taxa and holothurian taxa. The first two data sets are freely available in PANGAEA (Teschke and Brey, 2019a, b), and the latter is available from the following information system: http://biodiversity.aq/ (last access: 9 March 2020) (Gutt et al., 2014).
These data were used in a clustering approach to ultimately identify the potential habitat for echinoderms in the WSMPA Planning Area by environmental proxies (https://doi.org/10.1594/PANGAEA.899645, ; "Special echinoderm assemblage -pot habitat").

Fish
Antarctic silverfish and demersal fish The WSMPA data collection on Antarctic silverfish larvae (Pleuragramma antarctica) originates from quantitative zooplankton data sets obtained during the RV Polarstern cruises ANT-I/2 and ANT-III/3 and during the Lazarev Sea Krill Survey (LAKRIS) ( Table 2). The ANT-I/2 data are stored in the data warehouse of the Thünen Institute of Sea Fisheries and can be requested on demand (https:// www.thuenen.de/de/sf). Data on fish larvae from ANT-III/3 are available from Hubold et al. (1988), and the LAKRIS data can be requested from https://www.awi.de/forschung/ biowissenschaften/polare-biologische-ozeanographie (data request: 13 December 2013).
All abundance data on Antarctic silverfish (adults and larvae) were used for an interpolation approach and led to a map of the interpolated abundances of P. antarctica in the WSMPA Planning Area (https://doi.org/10.1594/PANGAEA.899591, Teschke et al., 2019c; "Antarctic silverfish, Pleuragramma antarcticainterpolated abundance").
All data on demersal fish were used in a SDM and led to a data layer product showing the habitat suitability for demersal fish in the WSMPA Planning Area (see https://doi.org/10.1594/PANGAEA.899591, Teschke et al., 2019c; "Demersal fish -habitat suitability prediction").

Demersal fish nesting sites
Information about nesting sites of demersal fish was collected during the RV Polarstern cruises PS82 (Knust and Schröder, 2014) and PS96 (Piepenburg, 2016). The data collected during the RV Polarstern cruises were supplemented by data from the literature (Daniels, 1978(Daniels, , 1979Jones and Near, 2012). The map with the locations of the nesting sites of demersal fish is available at PANGAEA (https://doi.org/10.1594/PANGAEA.899591, Teschke et al., 2019c; "Demersal fish -observation of nesting sites") and is also shown in the Supplement (see Fig. S12).

Flying and non-flying seabirds
Breeding and non-breeding Adélie penguins Tracking data on breeding and non-breeding Adélie penguins (Pygoscelis adeliae) originate from (i) British Antarctic Survey (BAS) inventory data (ID 754,764,773,779), (ii) a data set from BAS and Instituto Antártico Argentino (ID 753), and (iii) a data set from the US AMLR Program (NOAA) (ID 910) (see also Table 2). All the data are stored in Birdlife International's Seabird Tracking Database (http: //www.seabirdtracking.org/; data request: 20 October 2015). Adélie penguin breeding locations and estimated abundances of breeding pairs were derived from Lynch and LaRue (2014).
The tracking data on P. adeliae were used to model the probability of breeding and nonbreeding P. adeliae occurrence during foraging (https://doi.org/10.1594/PANGAEA.899520, ; "Breeding Adélie penguin, Pygoscelis adeliaemodelled foraging trip" and "Non-breeding Adélie penguin, Pygoscelis adeliae -modelled foraging trips"). The final data layer product for breeding P. adeliae also depicts breeding locations, estimated abundances of breeding pairs and buffer areas around each colony.

Breeding emperor penguins
Data on emperor penguin (Aptenodytes forsteri) colony locations and breeding population estimates were derived from Fretwell et al. (2012Fretwell et al. ( , 2014 (Table 2).

Antarctic petrels
Information on breeding locations and estimated number of breeding pairs of the Antarctic petrel (Thalassoica antarctica) is published in Van Franeker et al. (1999) ( Table 2).
The information on breeding pairs and their colony locations is shown in the final data layer product next to modelled foraging habitats of T. antarctica (https://doi.org/10.1594/PANGAEA.899520, Pehlke et al., 2019a; "Antarctic petrel, Thalassoica antarctica -modelled foraging areas").

Pinnipeds
Tracking data from pinnipeds were obtained from the MEOP data portal "Marine Mammals Exploring the Oceans Pole to Pole" available via http://www.meop.net/ (data request: 14 November 2016) (see Table 2 for a detailed list of data used). Furthermore, the data from the MEOP data portal were complemented by tracking data sets on southern elephant seals (Tosh et al., 2009a, b;James et al., 2012a, b), Weddell seals (McIntyre et al., 2013a, b) and crabeater seals (Nachtsheim et al., 2016a, b) stored in PANGAEA.
All of these tracking data were used to model the probability of seal occurrence during foraging (https://doi.org/10.1594/PANGAEA.899619, ; "Seal abundance -modelled prediction values").
Point data from pack-ice seals (unspecified taxa) based on aerial surveys are from Plötz et al. (2011a-e) and were downloaded from PANGAEA (Table 2). These data were sampled during five flight campaigns from 1996 to 2001 within the Antarctic Pack Ice Seals (APIS) programme. Additionally, information on crabeater seal density (predicted or observed) was derived from Bester et al. (1995Bester et al. ( , 2002, Flores et al. (2008) and Forcada et al. (2012; Table 2).
All the APIS point data and information on seal densities were used to develop a map showing the distribution patterns of seals in the WSMPA Planning Area (https://doi.org/10.1594/PANGAEA.899619, Pehlke et al., 2019b; "Seal abundance -modelled and interpolated prediction values").
Detailed information on how the data were compiled can be found in Sect. 2.2.

Outlook
This is the first compilation of data sources for the Antarctic Weddell Sea and adjacent seas that considers data across the entire ecosystem, i.e. from abiotic data, such as bathymetry and sea ice, to ecological data, ranging from zooplankton and zoobenthos to fish, birds, and marine mammals. The effort to create such a compilation of data sources was directly coupled with the initiative to develop a WSMPA. However, our compilation of data sources will facilitate the future research on fauna, ecology and nature conservation in the Weddell Sea. Using our systematic overview of available data for the development of a specific data collection, future projects can avoid performing this time-consuming multi-parameter data search from scratch. In addition, our work serves to guide future studies aimed at closing data gaps in the wider Weddell Sea region and/or simply pointing to specific data sets that may be of particular interest to future generations (baseline is a particular issue). For example, some of the ecological data sets were collected in the 1980s and earlier, when the Weddell Sea was still almost pristine and hardly affected by any anthropogenic activities, thus these data sets are optimally suited to describe a reference state for assessing the effect of pressures on the Weddell Sea ecosystem. In addition, the ecological data -with a few exceptions -provide information on abundances of the respective taxa and are therefore better suited for use as an indicator for environmental changes than presence-absence data or presence data only. Ultimately, the compilation of data sources serves to motivate researchers to incorporate further data, both from existing "paper sources" and from future measurements, into existing data repositories and archives. Subsequent work will focus on the development of an efficient and tailor-made management system for the storage of these complex and heterogeneous data and information on WSMPA data compilation and automated data mining, handling and analysis. This system will serve three purposes: (i) to better enable a more holistic and integrative approach towards ecosystem research in the Weddell Sea in general; (ii) to enable the management of the WSMPA to carry out the tasks of the Research and Monitoring Programme as a mandatory part of an MPA under CCAMLR when adopting the MPA; and (iii) to provide key stakeholders and the public with access to data, information, and management measures related to the ecosystem of the Weddell Sea region in general and the WSMPA in particular. The CCAMLR MPA Information Repository (CMIR) currently being developed by the CCAMLR Secretariat will also be available in the future as a suitable storage location for metadata on CCAMLR MPAs in Antarctica.
Author contributions. KT collected all of the data together, described the metadata and led the writing of the paper. HP took over the technical part of the data acquisition (retrieval, storage, processing). VS collected and prepared the data on zooplankton for further analyses within the WSMPA planning process. HB and RK were significantly involved in the collection of the data on pinnipeds and fishes, respectively. TB contributed to the writing of the paper.
Competing interests. The authors declare that they have no conflict of interest.
Acknowledgements. In particular, we would like to thank all of our colleagues from all of the national and international scientific institutions who have supported us in providing the data that we used to build up our data compilation for the wider Weddell Sea, i.e. from the Alfred Wegener Institute ( . The marine mammal data were collected and made freely available by the International MEOP Consortium and the national programmes that contribute to it (http: //www.meop.net, data request: 14 November 2016). The seal tracking data ct96 and ct109 are collected by the Integrated Marine Observing System (IMOS). IMOS is a national collaborative research infrastructure supported by the Australian Government. It is operated by a consortium of institutions as an unincorporated joint venture, with the University of Tasmania as its lead agent. We thank the two anonymous reviewers for their careful reading and constructive comments on the manuscript. Financial support. This research has been supported by the German Federal Ministry of Food and Agriculture (BMEL) through the Federal Office for Agriculture and Food (BLE) (grant no. 2813HS009).
Review statement. This paper was edited by Dirk Fleischer and reviewed by two anonymous referees.