Causal networks of phytoplankton diversity and biomass are modulated by environmental context.

Untangling causal links and feedbacks among biodiversity, ecosystem functioning, and environmental factors is challenging due to their complex and context-dependent interactions (e.g., a nutrient-dependent relationship between diversity and biomass).

Intraseasonal predictability of natural phytoplankton population dynamics.

It is difficult to make skillful predictions about the future dynamics of marine phytoplankton populations. Here, we use a 22-year time series of monthly average abundances for 198 phytoplankton taxa from Station L4 in the Western English Channel (1992-2014) to test whether and how aggregating phytoplankton into multi-species assemblages can improve predictability of their temporal dynamics. Using a non-parametric framework to assess predictability, we demonstrate that the prediction skill is significantly affected by how species data are grouped into assemblages, the presence of noise, and stochastic behavior within species.

Increasing picocyanobacteria success in shelf waters contributes to long-term food web degradation.

Continental margins are disproportionally important for global primary production, fisheries and CO uptake. However, across the Northeast Atlantic shelves, there has been an ongoing summertime decline of key biota-large diatoms, dinoflagellates and copepods-that traditionally fuel higher tropic levels such as fish, sea birds and marine mammals. Here, we combine multiple time series with in situ process studies to link these declines to summer nutrient stress and increasing proportions of picophytoplankton that can comprise up to 90% of the combined pico- and nanophytoplankton biomass in coastal areas.

BioTIME: A database of biodiversity time series for the Anthropocene.

Motivation: The BioTIME database contains raw data on species identities and abundances in ecological assemblages through time. These data enable users to calculate temporal trends in biodiversity within and amongst assemblages using a broad range of metrics. BioTIME is being developed as a community-led open-source database of biodiversity time series.

Effects of elevated CO on phytoplankton community biomass and species composition during a spring Phaeocystis spp. bloom in the western English Channel.

A 21-year time series of phytoplankton community structure was analysed in relation to Phaeocystis spp. to elucidate its contribution to the annual carbon budget at station L4 in the western English Channel (WEC). Between 1993-2014 Phaeocystis spp.

Long-term dynamics in a soft-bottom amphipod community and the influence of the pelagic environment.

The processes and patterns seen in coastal benthic communities can be strongly influenced by the overlying pelagic environmental conditions. Integrating long-term biological and environmental data (both benthic and pelagic) can give insight into the specific relationships between key benthic functional groups and natural temporal changes in the marine environment. The identity and abundance of amphipod species found at Station L4 (Western English Channel) were tracked for 7 years (2008-2014), whilst simultaneously, annual changes in phytoplankton biomass, water temperature, salinity and chlorophyll a concentration were also characterized.

Metabolically active, non-nitrogen fixing, in UK coastal waters during winter.

, a colonial cyanobacterium typically associated with tropical waters, was observed between January and April 2014 in the western English Channel. Sequencing of the heterocyst differentiation () and 16S rRNA genes placed this community within the Clade IV , an understudied clade previously found only in low numbers in warmer waters Nitrogen fixation was not detected although measurable rates of nitrate uptake and carbon fixation were observed. RuBisCO transcript abundance relative to gene abundance suggests the potential for viable and potentially active carbon fixation.

The influence of balanced and imbalanced resource supply on biodiversity-functioning relationship across ecosystems.

Numerous studies show that increasing species richness leads to higher ecosystem productivity. This effect is often attributed to more efficient portioning of multiple resources in communities with higher numbers of competing species, indicating the role of resource supply and stoichiometry for biodiversity-ecosystem functioning relationships. Here, we merged theory on ecological stoichiometry with a framework of biodiversity-ecosystem functioning to understand how resource use transfers into primary production.

Ocean net heat flux influences seasonal to interannual patterns of plankton abundance.

Changes in the net heat flux (NHF) into the ocean have profound impacts on global climate. We analyse a long-term plankton time-series and show that the NHF is a critical indicator of ecosystem dynamics. We show that phytoplankton abundance and diversity patterns are tightly bounded by the switches between negative and positive NHF over an annual cycle.