Shlomit Sharoni

Massachusetts Institute of Technology | MIT · Department of Earth Atmospheric and Planetary Sciences

Blooms of the coccolithophore Gephyrocapsa huxleyi (formerly Emiliania huxleyi) are routinely infected by a specific lytic virus (EhV) that kills host cells and drives bloom termination. However, the impact of EhV on nutrient retention and stoichiometric ratios of particulate organic matter remains unknown, limiting our current understanding of the...

Blooms of the dominant coccolithophore Emiliania huxleyi are routinely infected by a specific lytic virus (EhV), which rapidly kills host cells triggering bloom termination and organic and inorganic carbon export. However, the impact of EhV on the dynamic of resource acquisition and cellular stoichiometry remains unknown, limiting the current under...

Phosphate is an essential macronutrient for all organisms with a key role in setting levels of marine primary productivity. Despite its importance for marine biogeochemical cycles and its role in shaping the evolution of marine organisms, the factors controlling phosphate bioavailability on geologic timescales remain poorly understood. Here we deve...

Planktonic organic matter forms the base of the marine food web, and its nutrient content (C:N:P org ) governs material and energy fluxes in the ocean. Over Earth history, C:N:P org had a crucial role in marine metazoan evolution and global biogeochemical dynamics, but the geologic history of C:N:P org is unknown, and it is often regarded constant...

Significance The elemental composition of marine phytoplankton reflects their quality as a food source and regulates the flow of carbon, oxygen, and nutrients between the ocean, atmosphere, and rock reservoirs. Despite this importance, no systematic estimate exists of the geologic history of phytoplankton elemental composition, which is often regar...

Although the nutrient content of planktonic organic matter (C:N:Porg) plays a crucial role in marine metazoan evolution and global biogeochemistry (1–3), its geologic history is poorly constrained, and it is often regarded as a constant “Redfield” ratio of C:N:Porg~106:16:1. We calculate C:N:Porg through the Phanerozoic by including nutrient- and t...

Although phosphate is an essential macronutrient for marine biota, critical to our understanding of marine productivity, biogeochemistry, and evolution, its long-timescale geologic history is poorly constrained. We constrain weathering-derived fluxes and seawater concentrations of phosphate throughout the Phanerozoic (541 Ma to present), by develop...

The pairing of calcium and magnesium isotopes (δ 44/40 Ca, δ 26 Mg) has recently emerged as a useful tracer to understand the environmental information preserved in shallow-marine carbonates. Here, we applied a Ca and Mg isotopic framework, along with analyses of carbon and lithium isotopes, to late Tonian dolostones, to infer seawater chemistry ac...

A common assumption of a constant nitrogen-to-phosphorus ratio (N:P) of 16:1 in marine particulate organic matter (POM) appears to be invalidated by observations of major spatial variations in N:P. Two main explanations have been proposed. The first attributes the N:P variability to changes in the community composition of well-adapted phytoplankton...

Data S1. Coccolith Mass and Volume Concentration Calculations, Related to Table 1

Sea spray aerosols (SSA), have a profound effect on the climate; however, the contribution of oceanic microbial activity to SSA is not fully established. We assessed aerosolization of the calcite units (coccoliths) that compose the exoskeleton of the cosmopolitan bloom-forming coccolithophore, Emiliania huxleyi. Airborne coccolith emission occurs i...

Spatial characteristics of phytoplankton blooms often reflect the horizontal transport properties of the oceanic turbulent flow in which they are embedded. Classically, bloom response to horizontal stirring is regarded in terms of generation of patchiness following large-scale bloom initiation. Here, using satellite observations from the North Paci...

Supplementary Figures and Supplementary Table

Spatio-temporal evolution of the 2007 bloom. Sequence of multi-satellite chlorophyll observations. Each frame is a compositedof 8 consecutive images from the 3 sensors used (MODIS-Aqua, MODIS-Terra and MERIS). Spatial coverage is similar to that in Fig. 1. Time interval is 1 day. Arrows represent the geostrophic velocity vectors as derived from the...

Significance Marine viruses constitute a major ecological and evolutionary driving force in marine ecosystems and are responsible for cycling of major nutrients; however, their dispersal mechanisms remain underexplored. By using one of the most established host–pathogen planktonic model systems we provide strong evidence that specific viruses of ma...

Phytoplankton blooms are ephemeral events of exceptionally high primary productivity that regulate the flux of carbon across marine food webs [1, 2 and 3]. Quantification of bloom turnover [4] is limited by a fundamental difficulty to decouple between physical and biological processes as observed by ocean color satellite data. This limitation hinde...

Using shipboard and satellite measurements we explore the environmental factors affecting the number concentration of aerosols with diameter 100 < D < 1000 nm over a cluster of three mesoscale (~10-100 km) eddies in the North Atlantic. Strongest sensitivity to environmental conditions was found in the 400 < D < 1000 nm size range. In this size rang...