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Quantifying the impact of major cultural transitions on marine ecosystem functioning and biodiversity

Periodic Reporting for period 1 - SEACHANGE (Quantifying the impact of major cultural transitions on marine ecosystem functioning and biodiversity)

Reporting period: 2020-10-01 to 2022-03-31

The seas are changing. Marine conservation seeks to protect valuable habitats but the pristine state of marine ecosystem functioning and biodiversity – that is, the system as it operated before there was any large scale human impact – is conjectural. Conservation management strategies are often based on highly altered ecosystems where the degree of human-induced change is unknown. In SEACHANGE, we aim a structured and systematic approach to the reconstruction of marine ecosystem baselines to quantify the impact of anthropogenic cultural transitions on marine biodiversity and ecosystem functioning. SEACHANGE addresses two key questions: 1) What was the nature of long-term changes in prehistoric marine biodiversity and ecosystem functioning over a 3000-year period in NW Europe and the degree of human impact associated with major socioeconomic changes across the Mesolithic-Neolithic boundary? 2) What has been the scale and rate of marine biodiversity loss and changes to ecosystem functioning as a result of fishing intensity and marine habitat loss during the last 2000 years (including the Industrial Transition) in the North Sea and around Iceland, eastern Australia and the west Antarctic Peninsula?
To address these questions we are analysing: 1) absolutely-dated annually-resolved bivalve shell series; 2) marine sediment cores; 3) archaeological midden materials including shells and bones. We are dating these samples precisely and undertaking zooarchaeological and palaeoecological, stable isotope geochemical and environmental DNA/DNA analyses. We are comparing the data with historical and archival sources, and later in the project we will generate numerical ecosystem simulations. We will identify how the current marine environment differs from that before large scale human impact and what measures are needed, and how long will it take, for marine biodiversity to recover.
We are investigating five key cultural transitions which frame the proposed work packages (WP):
1. The European transition to farming (Mesolithic to Neolithic, 8K to 5K yrs BP; WP1)
2. The European pre-industrial to modern (last 2K yrs; WP2)
3. The Australian hunter-gatherer (aboriginal) to colonial (last 6K yrs; WP3)
4. The Viking age settlement of Iceland (WP4)
5. The advent of intensive whaling in Antarctica (WP5).
WPs 4 and 5 capture transitions from “fully pristine” to impacted ecosystems, in Iceland from before human settlement in AD 874 to the present day, and in Antarctica from pristine into the phase of intensive whaling starting in the 20th century. WP6 addresses data management.
Year 1 was significantly impacted by the Covid-19 pandemic, which delayed the planning of fieldwork and cruise activity. A major cruise to the North Sea and North Atlantic was postponed to 2022. Only when restrictions lifted gradually during the latter half of 2021 were sample collection visits, fieldwork, planning for seatime and staff recruitment able to proceed. As a result, this reporting period covers less than one year of effective research time. During this latter period, however, rapid progress has been made towards meeting the project aims in all six work packages. Project meetings were held in October 2020, June 2021 and January 2022. Steering Group meetings were held in February 2021, May 2021, October 2021 and January 2022. Planning for the N Atlantic cruise (April-May 2022) and the Orkney fieldtrip/workshop (July 2022) involved significant time and effort during the last part of 2021 and the start of 2022.

WP1 - The UoC group visited Stockholm in October 2021 to sample core MD04-2286 (Skagerrak) for pilot eDNA samples ahead of the collection of fresh core material during the cruise; these samples will also enable assessments of rates of eDNA degradation in previously collected sediment cores. These samples are currently being analysed at UoC. The Skagerrak contains the longest continuous sequence of Holocene sediments from the NW European continental shelf and so is a key target for the project. Good progress has been made at UoY with the analysis of previously collected oyster shell samples from Danish middens.

WP2 - Core MD04-2286 also contains a sedimentary record covering this timespan so the samples collected for eDNA in October 2021 will cover this WP. Samples of previously collected midden material from the excavation at Skail Farm on Orkney have been analysed at UoY, alongside newly acquired materials collected during a limited excavation in summer 2021. A major SEACHANGE excavation and project meeting to be held on Orkney in July 2022 is in the planning stage.
WP3 - We are assessing whether to focus field efforts on the Moreton Bay or Keppel Islands sectors of the Queensland coast. This has involved reviewing published and ongoing research on middens and marine cores. The goal is to initiate fieldwork and seatime during 2023.
WP4 - In June-July 2021 the first physical sampling trip of the project took place - members of the UoE team travelled to Reykjavik to sample previously collected sediment cores from the north Icelandic shelf. This allowed the UoC group to start working on sedimentary eDNA prior to the collection fresh core samples from the research cruise. These samples are currently being analysed at UoC. The laboratory visit was followed by a field visit to active archaeological excavations of midden sites in north Iceland to assess the suitability of these sites for addressing SEACHANGE aims.
WP5 - Sampling of previously collected multicore samples of seabed sediments for eDNA analysis at UoC was undertaken at UoE in July 2021. These samples are currently undergoing analysis and the first positive preliminary data on total biodiversity have been reported to SEACHANGE participants. These cores have also been dated using Pb isotopes at UoE to provide chronological control; these data indicate that the cores contain sedimentary records covering the last 60 to 120 years, confirming a timescale relevant for assessing changes since the advent of whaling activity.
WP6 (Data management). The data management structure has been devised with input from all partners and uploaded as a Data Management Plan (DMP - deliverable 1.1). The DMP has been designed to encourage as far as possible the FAIR (findable, accessible, interoperable and reusable) structure for open data availability.
SEACHANGE has developed new protocols for sampling eDNA in marine sediment cores, and the first eDNA results for Antarctica and Iceland are expected from UoC early in the next phase of the project. Significant advances have been made in the development of geochemical techniques applied to shell material. In JGU advances have been made in the development of techniques to measure compound-specific stable isotopes in from organic matter in the shell matrices, and N isotopes in bulk samples from shells. These findings demonstrate the potential of bivalve shells for the study of trophic ecology, oceanography and pollution. From UoE new advances in the application of machine learning (AI) in the reading and interpretation of shell growth increments will be published soon, significantly improving our ability to construct long and growth increment series from bivalve molluscs.

The upcoming fieldwork and seagoing research campaigns promise a step-change in the ability of the project to address the ultimate aims
Fig. 2. SEACHANGE participants undergoing training for the EU NW research cruise in March 22
Fig. 4. Preliminary investigation of midden sites in north Iceland.
Fig. 3. Sampling of North Atlantic Shelf sediment cores for eDNA, Reykjavik, June-July 21
Fig. 1. SEACHANGE participants at the first in-person meeting in Cornwall January 22