Climate change effects on plankton recruitment from coastal sediments.

In highly seasonal systems, the emergence of planktonic resting stages from the sediment is a key driver for bloom timing and plankton community composition. The termination of the resting phase is often linked to environmental cues, but the extent to which recruitment of resting stages is affected by climate change remains largely unknown for coastal environments. Here we investigate phyto- and zooplankton recruitment from oxic sediments in the Baltic Sea in a controlled experiment under proposed temperature and light increase during the spring and summer. We find that emergence of resting stage differs between seasons and the abiotic environment. Phytoplankton recruitment from resting stages were high in spring with significantly higher emergence rates at increased temperature and light levels for dinoflagellate and cyanobacteria than for diatoms, which had highest emergence under cold and dark conditions. In comparison, hatching of copepod nauplii was not affected by increased temperature and light levels. These results show that activation of plankton resting stages are affected to different degrees by increasing temperature and light levels, indicating that climate change affects plankton dynamics through processes related to resting stage termination with potential consequences for bloom timing, community composition and trophic mismatch.

Warming increases the compositional and functional variability of a temperate protist community.

Phototrophic protists are a fundamental component of the world's oceans by serving as the primary source of energy, oxygen, and organic nutrients for the entire ecosystem. Due to the high thermal seasonality of their habitat, temperate protists could harbour many well-adapted species that tolerate ocean warming. However, these species may not sustain ecosystem functions equally well. To address these uncertainties, we conducted a 30-day mesocosm experiment to investigate how moderate (12 °C) and substantial (18 °C) warming compared to ambient conditions (6 °C) affect the composition (18S rRNA metabarcoding) and ecosystem functions (biomass, gross oxygen productivity, nutritional quality - C:N and C:P ratio) of a North Sea spring bloom community. Our results revealed warming-driven shifts in dominant protist groups, with haptophytes thriving at 12 °C and diatoms at 18 °C. Species responses primarily depended on the species' thermal traits, with indirect temperature effects on grazing being less relevant and phosphorus acting as a critical modulator. The species Phaeocystis globosa showed highest biomass on low phosphate concentrations and relatively increased in some replicates of both warming treatments. In line with this, the C:P ratio varied more with the presence of P. globosa than with temperature. Examining further ecosystem responses under warming, our study revealed lowered gross oxygen productivity but increased biomass accumulation whereas the C:N ratio remained unaltered. Although North Sea species exhibited resilience to elevated temperatures, a diminished functional similarity and heightened compositional variability indicate potential ecosystem repercussions for higher trophic levels. In conclusion, our research stresses the multifaceted nature of temperature effects on protist communities, emphasising the need for a holistic understanding that encompasses trait-based responses, indirect effects, and functional dynamics in the face of exacerbating temperature changes.

Biotic interactions between benthic infauna and aerobic methanotrophs mediate methane fluxes from coastal sediments.

Coastal ecosystems dominate oceanic methane (CH4) emissions. However, there is limited knowledge about how biotic interactions between infauna and aerobic methanotrophs (i.e. CH4 oxidizing bacteria) drive the spatial-temporal dynamics of these emissions. Here, we investigated the role of meio- and macrofauna in mediating CH4 sediment-water fluxes and aerobic methanotrophic activity that can oxidize significant portions of CH4. We show that macrofauna increases CH4 fluxes by enhancing vertical solute transport through bioturbation, but this effect is somewhat offset by high meiofauna abundance. The increase in CH4 flux reduces CH4 pore-water availability, resulting in lower abundance and activity of aerobic methanotrophs, an effect that counterbalances the potential stimulation of these bacteria by higher oxygen flux to the sediment via bioturbation. These findings indicate that a larger than previously thought portion of CH4 emissions from coastal ecosystems is due to faunal activity and multiple complex interactions with methanotrophs.

High immunohistochemical expression of p-AKT predicts inferior survival in patients with diffuse large B-cell lymphoma treated with immunochemotherapy.

Chemotherapy and rituximab (R) is current standard therapy in diffuse large B-cell lymphoma (DLBCL), but a substantial proportion of patients still fail to reach sustained remission. In vitro studies have indicated that rituximab resistance could be accompanied by dysregulated apoptotic pathways, such as the phosphatidylinositol 3-kinase (PI3K)/AKT signaling pathway, which can be constitutively activated in DLBCL. In this retrospective, immunohistochemical study on 106 patients treated with R-CHO(E)P (cyclophosphamide, doxorubicin, vincristine, prednisone, rituximab [+etoposide]), we investigated the prognostic role of proteins involved in different apoptotic pathways; phosphorylated AKT (p-AKT), bcl-2, MCL1, bcl-xL, Bax and Bak. High p-AKT expression (>108 cells/mm2, highest quartile, n=27) predicted worse progression-free (PFS) (P=0.02) and overall (OS) (P=0.01) survival, independent of International Prognostic Index and sex. Also bcl-2+ (cut-off 50%) predicted worse PFS (P=0.005) and OS (P=0.05) but after adjustment for clinical factors only the influence on PFS (P=0.03) remained significant. The prognostic impact of p-AKT overexpression was independent of bcl-2 status. MCL1, bcl-xL, Bax and Bak expression did not add any prognostic information. Our results suggest that high p-AKT expression predicts worse outcome, possibly indicating that inhibition of the activated PI3K/AKT pathway could be of clinical interest in DLBCL patients. In addition, bcl-2 status could have prognostic importance also in the era of immunochemotherapy.