Global marine plankton functional type biomass distributions: Phaeocystis spp.

Vogt, M. ... et. al.-- 14 pages, 9 figures, 4 tables, 1 appendix, The original and gridded data can be downloaded from PANGAEA: https://doi.org/10.1594/PANGAEA.779101The planktonic haptophyte Phaeocystis has been suggested to play a fundamental role in the global biogeochemical cycling of carbon and sulphur, but little is known about its global biomass distribution. We have collected global microscopy data of the genus Phaeocystis and converted abundance data to carbon biomass using species-specific carbon conversion factors. Microscopic counts of single-celled and colonial Phaeocystis were obtained both through the mining of online databases and by accepting direct submissions (both published and unpublished) from Phaeocystis specialists. We recorded abundance data from a total of 1595 depth-resolved stations sampled between 1955–2009. The quality-controlled dataset includes 5057 counts of individual Phaeocystis cells resolved to species level and information regarding life-stages from 3526 samples. 83% of stations were located in the Northern Hemisphere while 17% were located in the Southern Hemisphere. Most data were located in the latitude range of 50–70º N. While the seasonal distribution of Northern Hemisphere data was well-balanced, Southern Hemisphere data was biased towards summer months. Mean species- and form-specific cell diameters were determined from previously published studies. Cell diameters were used to calculate the cellular biovolume of Phaeocystis cells, assuming spherical geometry. Cell biomass was calculated using a carbon conversion factor for prymnesiophytes. For colonies, the number of cells per colony was derived from the colony volume. Cell numbers were then converted to carbon concentrations. An estimation of colonial mucus carbon was included a posteriori, assuming a mean colony size for each species. Carbon content per cell ranged from 9 pg C cell−1 (single-celled Phaeocystis antarctica) to 29 pgC cell−1 (colonial Phaeocystis globosa). Non-zero Phaeocystis cell biomasses (without mucus carbon) range from 2.9 × 10−5 to 5.4 × 103 μg Cl−1, with a mean of 45.7 μg Cl−1 and a median of 3.0 μg Cl−1. The highest biomasses occur in the Southern Ocean below 70º S (up to 783.9 μg Cl−1) and in the North Atlantic around 50º N (up to 5.4 × 103 μg Cl−1). The original and gridded data can be downloaded from PANGAEA, doi:10.1594/PANGAEA.779101Peer Reviewe

Interaction matters: Bottom‐up driver interdependencies alter the projected response of phytoplankton communities to climate change

Phytoplankton growth is controlled by multiple environmental drivers, which are all modified by climate change. While numerous experimental studies identify interactive effects between drivers, large-scale ocean biogeochemistry models mostly account for growth responses to each driver separately and leave the results of these experimental multiple-driver studies largely unused. Here, we amend phytoplankton growth functions in a biogeochemical model by dual-driver interactions (CO2 and temperature, CO2 and light), based on data of a published meta-analysis on multiple-driver laboratory experiments. The effect of this parametrization on phytoplankton biomass and community composition is tested using present-day and future high-emission (SSP5-8.5) climate forcing. While the projected decrease in future total global phytoplankton biomass in simulations with driver interactions is similar to that in control simulations without driver interactions (5%-6%), interactive driver effects are group-specific. Globally, diatom biomass decreases more with interactive effects compared with the control simulation (-8.1% with interactions vs. no change without interactions). Small-phytoplankton biomass, by contrast, decreases less with on-going climate change when the model accounts for driver interactions (-5.0% vs. -9.0%). The response of global coccolithophore biomass to future climate conditions is even reversed when interactions are considered (+33.2% instead of -10.8%). Regionally, the largest difference in the future phytoplankton community composition between the simulations with and without driver interactions is detected in the Southern Ocean, where diatom biomass decreases (-7.5%) instead of increases (+14.5%), raising the share of small phytoplankton and coccolithophores of total phytoplankton biomass. Hence, interactive effects impact the phytoplankton community structure and related biogeochemical fluxes in a future ocean. Our approach is a first step to integrate the mechanistic understanding of interacting driver effects on phytoplankton growth gained by numerous laboratory experiments into a global ocean biogeochemistry model, aiming toward more realistic future projections of phytoplankton biomass and community composition

Evaluation of Madurahydroxylactone as a Slow Release Antibacterial Implant Coating

Madurahydroxylactone (MHL), a secondary metabolite with antibacterial activity was evaluated for its suitability to generate controlled drug release coatings on medical implant materials. A smooth and firmly attached layer could be produced from a precursor solution on various metallic implant materials. In physiological salt solutions these coatings dissolved within a time period up to one week. A combination of MHL with a broad spectrum fluoroquinolone antibiotic was used to create a coating that was active against all bacterial strains tested. The time period during which the coating remained active against Pseudomonas aeruginosa was investigated. The results indicated a delayed drug release from single layer coatings in the course of seven days. MHL was biocompatible in cell culture assays and could after a delay even serve as a cell adhesion substrate for human or murine cells. The findings indicate a potential for MHL for the generation of delayed release antimicrobial implant coatings

AtlantECO Deliverable 2.1: AtlantECO-BASE1

This deliverable reports on Task 2.2 ‘Assembly of observations about microbiomes, plastics, the plastisphere and carbon fluxes’. It used protocols established in task 2.1 ‘Definition of common standards for the assembly of spatially explicit data’ to compile, quality-control and grid existing high-quality observations into a knowledge base of observations (D2.1). Data included into AtlantECO-BASE1 consisted of contributions from the five following data sources and tasks: Task 2.2.1 ‘Microbiome data from traditional microscopy (presence-absence, abundance and biomass)’, Task 2.2.2 ‘Microbiome data from state-of-the-art optical/imaging analysis’, Task 2.2.3 ‘Microbiome and plastisphere data from state-of-the-art genetic analyses’, Task 2.2.4 ‘Nano-, micro and macroplastics data from state-of-the-art sampling methods’, and Task 2.2.5 ‘Carbon flux data from estimated from high resolution bio-optical sensors’. Additional data contributions and mapping efforts from other partners and work packages (Task 2.3) are also included. A comprehensive list and description of all data sets collected can be found in the Appendix Tables to this document

Globally consistent quantitative observations of planktonic ecosystems

In this paper we review the technologies available to make globally quantitative observations of particles in general—and plankton in particular—in the world oceans, and for sizes varying from sub-microns to centimeters. Some of these technologies have been available for years while others have only recently emerged. Use of these technologies is critical to improve understanding of the processes that control abundances, distributions and composition of plankton, provide data necessary to constrain and improve ecosystem and biogeochemical models, and forecast changes in marine ecosystems in light of climate change. In this paper we begin by providing the motivation for plankton observations, quantification and diversity qualification on a global scale. We then expand on the state-of-the-art, detailing a variety of relevant and (mostly) mature technologies and measurements, including bulk measurements of plankton, pigment composition, uses of genomic, optical and acoustical methods as well as analysis using particle counters, flow cytometers and quantitative imaging devices. We follow by highlighting the requirements necessary for a plankton observing system, the approach to achieve it and associated challenges. We conclude with ranked action-item recommendations for the next 10 years to move toward our vision of a holistic ocean-wide plankton observing system. Particularly, we suggest to begin with a demonstration project on a GO-SHIP line and/or a long-term observation site and expand from there, ensuring that issues associated with methods, observation tools, data analysis, quality assessment and curation are addressed early in the implementation. Global coordination is key for the success of this vision and will bring new insights on processes associated with nutrient regeneration, ocean production, fisheries and carbon sequestration

Marine production of DMS and its interaction with climate

EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Factors controlling the competition between Phaeocystis and diatoms in the Southern Ocean

The high-latitude Southern Ocean phytoplankton community is shaped by the competition between Phaeocystis and silicifying diatoms, with the relative abundance of these two groups controlling primary and export production, the production of dimethylsulfide, the ratio of silicic acid and nitrate available in the water column, and the structure of the food web. Here, we investigate this competition using a regional physical-biogeochemical-ecological model (ROMS-BEC) configured at eddy-permitting resolution for the Southern Ocean south of 35° S. We extended ROMS-BEC by an explicit parameterization of Phaeocystis colonies, so that the model, together with the previous addition of an explicit coccolithophore type, now includes all biogeochemically relevant Southern Ocean phytoplankton types. We find that Phaeocystis contribute 46 % and 40 % to annual NPP and POC export south of 60° S, respectively, making them an important contributor to high-latitude carbon cycling. In our simulation, the relative importance of Phaeocystis and diatoms is mainly controlled by the temporal variability in temperature and iron availability. The higher light sensitivity of Phaeocystis at low irradiances promotes the succession from Phaeocystis to diatoms in more coastal areas, such as the Ross Sea. Still, differences in the biomass loss rates, such as aggregation or grazing by zooplankton, need to be considered to explain the simulated seasonal biomass evolution.ISSN:1810-6277ISSN:1810-628