Depth-dependent bacterial colonization on model chitin particles in the open ocean.

Sinking particles transport carbon from the surface to the deep ocean. Microbial colonization and remineralization are important ecosystem services constraining ocean biogeochemistry by recycling and redistributing nutrients from the surface to the deep ocean. Fragmentation of particles by zooplankton and the resulting colonization by microorganisms before ingestion, known as 'microbial gardening', allows for trophic upgrading and increased microbial biomass for detritivorous zooplankton.

Metatranscriptomics reveals diversity of symbiotic interaction and mechanisms of carbon exchange in the marine cyanolichen Lichina pygmaea.

Lichens are exemplar symbioses based upon carbon exchange between photobionts and their mycobiont hosts. Historically considered a two-way relationship, some lichen symbioses have been shown to contain multiple photobiont partners; however, the way in which these photobiont communities react to environmental change is poorly understood. Lichina pygmaea is a marine cyanolichen that inhabits rocky seashores where it is submerged in seawater during every tidal cycle.

A 17-year time-series of fungal environmental DNA from a coastal marine ecosystem reveals long-term seasonal-scale and inter-annual diversity patterns.

Changing patterns in diversity are a feature of many habitats, with seasonality a major driver of ecosystem structure and function. In coastal marine plankton-based ecosystems, seasonality has been established through long-term time-series of bacterioplankton and protists. Alongside these groups, fungi also inhabit coastal marine ecosystems.

A cellular and molecular atlas reveals the basis of chytrid development.

The chytrids (phylum Chytridiomycota) are a major fungal lineage of ecological and evolutionary importance. Despite their importance, many fundamental aspects of chytrid developmental and cell biology remain poorly understood. To address these knowledge gaps, we combined quantitative volume electron microscopy and comparative transcriptome profiling to create an 'atlas' of the cellular and molecular basis of the chytrid life cycle, using the model chytrid .

Macromolecular composition and substrate range of three marine fungi across major cell types.

Marine fungi exist as three major cell types: unicellular yeasts, filamentous hyphae and zoosporic early-diverging forms, such as the Chytridiomycota (chytrids). To begin to understand the ecological and biogeochemical influence of these cell types within the wider context of other plankton groups, cell size and macromolecular composition must be assessed across all three cell types. Using a mass-balance approach to culture, we describe quantitative differences in substrate uptake and subsequent macromolecular distribution in three model marine fungi: the yeast , the filamentous and chytrid .

Chytrid fungi shape bacterial communities on model particulate organic matter.

Microbial colonization and degradation of particulate organic matter (POM) are important processes that influence the structure and function of aquatic ecosystems. Although POM is readily used by aquatic fungi and bacteria, there is a limited understanding of POM-associated interactions between these taxa, particularly for early-diverging fungal lineages. Using a model ecological system with the chitin-degrading freshwater chytrid fungus and chitin microbeads, we assessed the impacts of chytrid fungi on POM-associated bacteria.

Blue pigmentation of neustonic copepods benefits exploitation of a prey-rich niche at the air-sea boundary.

The sea-surface microlayer (SML) at the air-sea interface is a distinct, under-studied habitat compared to the subsurface and copepods, important components of ocean food webs, have developed key adaptations to exploit this niche. By using automated SML sampling, high-throughput sequencing and unmanned aerial vehicles, we report on the distribution and abundance of pontellid copepods in relation to the unique biophysicochemical signature of the SML. We found copepods in the SML even during high exposure to sun-derived ultraviolet radiation and their abundance was significantly correlated to increased algal biomass.

Active bacterioplankton community response to dissolved 'free' deoxyribonucleic acid (dDNA) in surface coastal marine waters.

Seawater contains dissolved 'free' DNA (dDNA) that is part of a larger <0.2 µm pool of DNA (D-DNA) including viruses and uncharacterised bound DNA. Previous studies have shown that bacterioplankton readily degrade dDNA, and culture-based approaches have identified several potential dDNA-utilising taxa.