Viral Infection Leads to a Unique Suite of Allelopathic Chemical Signals in Three Diatom Host-Virus Pairs.

Ecophysiological stress and the grazing of diatoms are known to elicit the production of chemical defense compounds called oxylipins, which are toxic to a wide range of marine organisms. Here we show that (1) the viral infection and lysis of diatoms resulted in oxylipin production; (2) the suite of compounds produced depended on the diatom host and the infecting virus; and (3) the virus-mediated oxylipidome was distinct, in both magnitude and diversity, from oxylipins produced due to stress associated with the growth phase. We used high-resolution accurate-mass mass spectrometry to observe changes in the dissolved lipidome of diatom cells infected with viruses over 3 to 4 days, compared to diatom cells in exponential, stationary, and decline phases of growth.

Building an inclusive wave in marine science: Sense of belonging and Society for Women in Marine Science symposia.

Achieving gender equity is a long-standing and ubiquitous challenge in marine science. Creating equitable experiences for all genders in marine science requires recognizing scientists' intersectional identities, and how this leads to unique lived experiences of privilege and marginalization. One approach to increase equitable experiences for women in marine science is to create affinity groups where women can learn from each other, share their experiences, and provide support and mentorship.

Lipid Biogeochemistry and Modern Lipidomic Techniques.

Lipids are structurally diverse biomolecules that serve multiple roles in cells. As such, they are used as biomarkers in the modern ocean and as paleoproxies to explore the geological past. Here, I review lipid geochemistry, biosynthesis, and compartmentalization; the varied uses of lipids as biomarkers; and the evolution of analytical techniques used to measure and characterize lipids.

Correcting a major error in assessing organic carbon pollution in natural waters.

Microbial degradation of dissolved organic carbon (DOC) in aquatic environments can cause oxygen depletion, water acidification, and CO emissions. These problems are caused by labile DOC (LDOC) and not refractory DOC (RDOC) that resists degradation and is thus a carbon sink. For nearly a century, chemical oxygen demand (COD) has been widely used for assessment of organic pollution in aquatic systems.

Biological composition and microbial dynamics of sinking particulate organic matter at abyssal depths in the oligotrophic open ocean.

Sinking particles are a critical conduit for the export of organic material from surface waters to the deep ocean. Despite their importance in oceanic carbon cycling and export, little is known about the biotic composition, origins, and variability of sinking particles reaching abyssal depths. Here, we analyzed particle-associated nucleic acids captured and preserved in sediment traps at 4,000-m depth in the North Pacific Subtropical Gyre.

LOBSTAHS: An Adduct-Based Lipidomics Strategy for Discovery and Identification of Oxidative Stress Biomarkers.

Discovery and identification of molecular biomarkers in large LC/MS data sets requires significant automation without loss of accuracy in the compound screening and annotation process. Here, we describe a lipidomics workflow and open-source software package for high-throughput annotation and putative identification of lipid, oxidized lipid, and oxylipin biomarkers in high-mass-accuracy HPLC-MS data. Lipid and oxylipin biomarker screening through adduct hierarchy sequences, or LOBSTAHS, uses orthogonal screening criteria based on adduct ion formation patterns and other properties to identify thousands of compounds while providing the user with a confidence score for each assignment.

Dose-dependent regulation of microbial activity on sinking particles by polyunsaturated aldehydes: Implications for the carbon cycle.

Diatoms and other phytoplankton play a crucial role in the global carbon cycle, fixing CO2 into organic carbon, which may then be exported to depth via sinking particles. The molecular diversity of this organic carbon is vast and many highly bioactive molecules have been identified. Polyunsaturated aldehydes (PUAs) are bioactive on various levels of the marine food web, and yet the potential for these molecules to affect the fate of organic carbon produced by diatoms remains an open question.

Draft genome sequence of strain HIMB100, a cultured representative of the SAR116 clade of marine Alphaproteobacteria.

Strain HIMB100 is a planktonic marine bacterium in the class Alphaproteobacteria. This strain is of interest because it is one of the first known isolates from a globally ubiquitous clade of marine bacteria known as SAR116 within the family Rhodospirillaceae. Here we describe preliminary features of the organism, together with the draft genome sequence and annotation.

Constitutive Extracellular Polysaccharide (EPS) Production by Specific Isolates of Crocosphaera watsonii.

Unicellular dinitrogen (N(2)) fixing cyanobacteria have only recently been identified in the ocean and recognized as important contributors to global N(2) fixation. The only cultivated representatives of the open ocean unicellular diazotrophs are multiple isolates of Crocosphaera watsonii. Although constituents of the genus are nearly genetically identical, isolates have been described in two size classes, large ∼5 μm and small ∼3 μm cell diameters.