The BEPSII research community is dedicated to study, review, evaluate and model these processes and exchanges in the sea-ice zone in both Arctic and Antarctic. Trying to understand the role of sea ice in the Earth System means embracing a complex system of processes, where micro-scales have far-reaching implications from the regional to the global scale. In order to understand this system, it is a prerequisite that the main processes and feedbacks are examined at each scale from an integrated perspective. The BEPSII community tackles these issues by concerted interaction between field scientists and modelers.

To date, BEPSII has promoted the publication of scientific papers and reviews, conducted cross-cutting community workshops, the compilation and release of observational databases, initiated community model inter-comparisons, and identified critical requirements for methodological developments, data-quality control and data mining efforts. BEPSII achieved many of its goals with respect to synthesizing available sea-ice biogeochemical research and establishing an active and coordinated community of sea-ice biogeochemical researchers. The need to continue the work within such a community with the winding down of the SCOR working group has been recognized by several other science and research organizations. BEPSII is now entering its second phase as a research community with support from SOLAS, CliC and SCAR and will continue to seek support from international and national organizations. In an effort to build upon the work initiated by SCOR WG 140, and the many findings and successes of the program, as evidenced by contributions to a Special Feature in Elementa and to other journals, BEPSII has formulated new goals and objectives:

1) to develop dedicated and consistent methodologies for sea-ice biogeochemical research - This task is partly handled by the ECV-ice network

2) to establish effective sea-ice biogeochemical data-archiving approaches and databases

3) to foster process studies determining impacts of sea ice on ecology and biogeochemical cycles

4) to foster technological developments and international knowledge transfer towards large-scale, autonomous and high-frequency sampling of sea-ice biogeochemical parameters

5) to improve the representation and evaluation of sea-ice biogeochemistry in regional and Earth system numerical models

6) to synthesize and integrate observational and modeling efforts

7) to regularly revise and renew scientific foci, teams, and objectives

8) to develop conceptual models describing sea-ice interactions in or within the Earth system

Task groups

BEPSII’s new goals will be addressed by five task groups, each focused on one of the goal-encompassing topics that follow:

  • Methodologies

Method intercalibration studies, a need strongly highlighted in the BEPSII research community, will be developed within the SCOR working group ECVice. Current intercalibration efforts are focused on gas concentration measurement techniques in sea ice. Experiments will be performed at the Roland von Glasow ice tank facility at the University of East Anglia (UK) in summer 2018. Intercalibration of primary production measurement techniques are also planned. A first intercalibration experiment is planned in Saroma-Ko (Japan) in March 2018, during which most of the up-to-date techniques available will be tested (i.e., biomass accumulation, (isotopic-tracer) incubations, O2:Ar ratio, under-ice eddy covariance …). CHARS station at Cambridge Bay in the Canadian Arctic Archipelago is currently being evaluated as location for an additional experiment in 2019, including additional techniques (e.g., under-ice microelectrode, …). In addition to primary production, this will also include an assessment of tracer incubation protocols for general metabolic rate determinations in sea ice (e.g., bacterial production, nutrient transformations). Previous experiments include sample storage and processing for trace-metals (PIPERS, Ross Sea, 2017) as well as for nutrients and biomass (Saroma-Ko, Japan, 2016). Finally, development of new techniques for light measurements within and under sea ice are under discussion.

The task group will also design experiments and collate results from ice tank facilities and field campaigns to investigate and possibly isolate specific biogeochemical processes currently not represented in models and pursue the vision of creating a guide of best practices in an interactive on-line document. All of these efforts aim at unifying observational procedures and methods to enhance reproducibility and comparability among internationally conducted polar field projects.

  • Technology and Data Collation

Many biogeochemical sensors that have been developed for temperate or open-ocean conditions need to be adjusted for use in polar conditions. Remotely controlled platforms will allow to circumvent accessibility issues (e.g., under sea ice). Coordinated development and validation will expand our capability for biogeochemical measurements in sea-ice environments. BEPSII as a program is ideally

suited to support the development and validation of in-situ platforms and sensors development. BEPSII as a community of researchers also continues to pursue its initial work on historical data collation and analysis (e.g. Meiners et al. 2012, Lannuzel et al. 2016, Fripiat et al. 2017). Efforts are currently in progress to collate datasets for Antarctic fast ice chlorophyll-a, Arctic sea-ice chlorophyll-a, Antarctic sea-ice DIC/TA, sea ice 18O-H2O, Antarctic sea-ice particulate and dissolved organic carbon and Arctic

sea-ice nutrients. Efforts will be extended towards tools and protocols for gene-based community assessments and international networking on laboratory ice-tank facilities.

  • Modeling and Observational Process Studies

One of the BEPSII’s efforts is to design consistent and reproducible time-series process studies for multidisciplinary projects, so as to improve the usefulness and efficacy of observational data for models. Other process studies and analyses will focus on ridge-associated processes, the impact of biochemistry on physical ice properties, light transmission and ecological responses to changes in sea ice, and sea-ice algal phenology. Studies on the interactions between snow and sea ice is a collaborative action with IGAC’s Cryospheric Atmospheric Chemistry (CATCH). An important task is to upscale local process studies to regional scales, which includes studies of representativeness and patchiness of observations.

Continued development and intercomparison of 1-D sea ice biogeochemical models will allow to select relevant parameterizations that warrant implementation in regional or global models. The inclusion of sea-ice biogeochemistry in regional models is currently expanding, and intercomparisons of 3-D models are being planned within the framework of the Forum of Arctic Modeling and Observational Synthesis (FAMOS) and within the SCAR scientific research program Antarctic Climate Change in the 21st Century (AntClim).

  • Syntheses

One essential component of synthesizing processes and developing model parameterizations is the development of conceptual models that describe linkages of biogeochemical processes between sea ice and surrounding environments, including sea ice-pelagic-benthic coupling, sea ice-pelagic-terrestrial coupling, and atmosphere-snow-sea ice coupling. For many of the interactions involving the sea-ice environment our understanding across multiple space and time scales is very limited. There are clear needs to discuss linkages in a multi-disciplinary environment, address open questions and unknowns via specific testing in field projects, hypotheses testing also with models, and model intercomparison projects. BEPSII will also establish links to related processes on a paleo-climatic timescale via the Past Global Changes (PAGES) working group on sea-ice proxies (SIP).

Many of the linkages and functional interactions among the biological communities associated with sea ice are insufficiently known. These include interactions within the microbial foodweb, seeding of pelagic primary and secondary production, and cascading links to higher trophic levels. Identifying and analyzing these and other linkages are crucial to infer the impacts of changing Arctic and

Antarctic environments on polar ecosystems and biodiversity and to improving confidence in ecosystem models.

  • Outreach

In response to changing sea ice conditions, human activities such as subsistence fisheries and hunting, tourism, resource extraction and shipping have been changing and will continue to do so. Most human activities affect biogeochemical processes either directly as through the deposition of contaminants on ice and into the ocean, or indirectly through atmospheric and oceanic warming and ocean acidification. Changes in sea ice conditions and sea-ice algal production, directly impact species that rely on sea ice as their habitat and source of food, e.g., zooplankton species and higher trophic levels such as polar cod Boreogadus saida (Kohlbach et al., 2016; 2017), but also affect the exchange, uptake, release and production of climate-active gases. Hence, BEPSII is investigating sea-ice biogeochemical processes and polar ecosystem linkages, and assessing their potential future responses to anthropogenic forcing. BEPSII is committed to provide guidance to stakeholders and policy makers via involvement in the Arctic Council’s Arctic Monitoring and Assessment Program (AMAP), IASC and SCAR.

BEPSII is building capacity by strongly supporting early-career scientists and students. Efforts include the organization of a field school in April 2019 at CHARS station (Cambridge Bay, Canada), travel support to annual meetings, and encouragement to take on leadership roles in synthesizing available information within own field of expertise with mentoring from senior scientists.

BEPSII results and work plans are made available to the scientific community and the general public via social media such as Facebook (@SCOR.BEPSII) and Twitter (@BEPSII_seaice) and the BEPSII website.