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Climate and ecosystem dynamics vary across timescales, but research into climate-driven vegetation dynamics usually focuses on singular timescales. We developed a spectral analysis–based approach that provides detailed estimates of the timescales at which vegetation tracks climate change, from 10¹to 10⁵years. We report dynamic similarity of vegetation and climate even at centennial frequencies (149⁻¹to 18,012⁻¹year⁻¹, that is, one cycle per 149 to 18,012 years). A breakpoint in vegetation turnover (797⁻¹year⁻¹) matches a breakpoint between stochastic and autocorrelated climate processes, suggesting that ecological dynamics are governed by climate across these frequencies. Heightened vegetation turnover at millennial frequencies (4650⁻¹year⁻¹) highlights the risk of abrupt responses to climate change, whereas vegetation-climate decoupling at frequencies >149⁻¹year⁻¹may indicate long-lasting consequences of anthropogenic climate change for ecosystem function and biodiversity. 

Abstract. Anthropogenic warming and nutrient over-enrichment of our oceans have resulted in significant, and often catastrophic, reductions in dissolved oxygen (deoxygenation). Stress on water-breathing animals from this deoxygenation has been shown to occur at all levels of biological organization: cellular, organ, individual, species, population, community, and ecosystem. Most climate forecasts predict increases in ocean deoxygenation; thus, it is essential to develop reliable biological indicators of low-oxygen stress that can be used by regional and global oxygen monitoring efforts to detect and assess the impacts of deoxygenation on ocean life. This review focuses on responses to low-oxygen stress that are manifest at different levels of biological organization and at a variety of spatial and temporal scales. We compare particular attributes of these biological indicators to the dissolved oxygen threshold of response, timescales of response, sensitive life stages and taxa, and the ability to scale the response to oxygen stress across levels of organization. Where there is available evidence, we discuss the interactions of other biological and abiotic stressors on the biological indicators of low-oxygen stress. We address the utility, confounding effects, and implementation of the biological indicators of oxygen stress for research and societal applications. Our hope is that further refinement and dissemination of these oxygen stress indicators will provide more direct support for environmental managers, fisheries and mariculture scientists, conservation professionals, and policymakers to confront the challenges of ocean deoxygenation. An improved understanding of the sensitivity of different ocean species, communities, and ecosystems to low-oxygen stress will empower efforts to design monitoring programs, assess ecosystem health, develop management guidelines, track conditions, and detect low-oxygen events. 

Abstract We investigated the biogeography of benthic foraminifera in a highly urbanized tropical seascape, i.e. Hong Kong, in order to assess their utility as bioindicators relative to other marine fauna. Hong Kong is one of the largest coastal cities on the planet and studies of other benthic fauna in the region are available for comparison. We found that: (1) turbid, muddy habitats host a unique foraminiferal fauna; (2) areas with intermediate levels of eutrophication have the highest foraminiferal species diversity; (3) semi-enclosed and heavily polluted environments host a distinct foraminiferal fauna, characterized by low taxonomic diversity and/or high dominance, and that is acclimated to stressful marine conditions. Biodiversity patterns of foraminifera in Hong Kong are generally consistent with those of other soft-sediment macro- and meio-fauna (e.g. polychaetes, molluscs and ostracods); however, foraminifera may be more sensitive than these other groups to eutrophication and associated changes in coastal food webs. The tolerance of some, but not other, species to eutrophic and hypoxic conditions means that foraminiferal faunas can serve as bioindicators across a wide array of environmental conditions, in contrast with corals whose sensitivity to eutrophication results in their absence from eutrophied settings. The well-known autoecology of foraminifera taxa can help to characterize environmental conditions of different habitats and regional environmental gradients. Although the use of fauna as bioindicators may be most robust when data are compared for multiple taxonomic groups, when such broad sampling is not available, benthic foraminifera are particularly well suited for environmental assessments due to their ubiquity, interspecific environmental breadth, and the well-understood environmental preference of individual taxa. 

In this paper, we outline the need for a coordinated international effort toward the building of an open-access Global Ocean Oxygen Database and ATlas (GO 2 DAT) complying with the FAIR principles (Findable, Accessible, Interoperable, and Reusable). GO 2 DAT will combine data from the coastal and open ocean, as measured by the chemical Winkler titration method or by sensors (e.g., optodes, electrodes) from Eulerian and Lagrangian platforms (e.g., ships, moorings, profiling floats, gliders, ships of opportunities, marine mammals, cabled observatories). GO 2 DAT will further adopt a community-agreed, fully documented metadata format and a consistent quality control (QC) procedure and quality flagging (QF) system. GO 2 DAT will serve to support the development of advanced data analysis and biogeochemical models for improving our mapping, understanding and forecasting capabilities for ocean O 2 changes and deoxygenation trends. It will offer the opportunity to develop quality-controlled data synthesis products with unprecedented spatial (vertical and horizontal) and temporal (sub-seasonal to multi-decadal) resolution. These products will support model assessment, improvement and evaluation as well as the development of climate and ocean health indicators. They will further support the decision-making processes associated with the emerging blue economy, the conservation of marine resources and their associated ecosystem services and the development of management tools required by a diverse community of users (e.g., environmental agencies, aquaculture, and fishing sectors). A better knowledge base of the spatial and temporal variations of marine O 2 will improve our understanding of the ocean O 2 budget, and allow better quantification of the Earth’s carbon and heat budgets. With the ever-increasing need to protect and sustainably manage ocean services, GO 2 DAT will allow scientists to fully harness the increasing volumes of O 2 data already delivered by the expanding global ocean observing system and enable smooth incorporation of much higher quantities of data from autonomous platforms in the open ocean and coastal areas into comprehensive data products in the years to come. This paper aims at engaging the community (e.g., scientists, data managers, policy makers, service users) toward the development of GO 2 DAT within the framework of the UN Global Ocean Oxygen Decade (GOOD) program recently endorsed by IOC-UNESCO. A roadmap toward GO 2 DAT is proposed highlighting the efforts needed (e.g., in terms of human resources).