Geologic controls on phytoplankton elemental composition.

Planktonic organic matter forms the base of the marine food web, and its nutrient content (C:N:P) governs material and energy fluxes in the ocean. Over Earth history, C:N:P had a crucial role in marine metazoan evolution and global biogeochemical dynamics, but the geologic history of C:N:P is unknown, and it is often regarded constant at the "Redfield" ratio of ∼106:16:1. We calculated C:N:P through Phanerozoic time by including nutrient- and temperature-dependent C:N:P parameterizations in a model of the long-timescale biogeochemical cycles.

Geologic controls on phytoplankton elemental composition.

Planktonic organic matter forms the base of the marine food web, and its nutrient content (C:N:P) governs material and energy fluxes in the ocean. Over Earth history, C:N:P had a crucial role in marine metazoan evolution and global biogeochemical dynamics, but the geologic history of C:N:P is unknown, and it is often regarded constant at the "Redfield" ratio of ∼106:16:1. We calculated C:N:P through Phanerozoic time by including nutrient- and temperature-dependent C:N:P parameterizations in a model of the long-timescale biogeochemical cycles.

Nutrient ratios in marine particulate organic matter are predicted by the population structure of well-adapted phytoplankton.

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.

Infection Dynamics of a Bloom-Forming Alga and Its Virus Determine Airborne Coccolith Emission from Seawater.

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 in steady-state conditions and increases by an order of magnitude during E.

Dispersion/dilution enhances phytoplankton blooms in low-nutrient waters.

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 Pacific Subtropical Gyre and a simple ecosystem model, we show that the opposite scenario of turbulence dispersing and diluting fine-scale (∼1-100 km) nutrient-enriched water patches has the critical effect of regulating the dynamics of nutrients-phytoplankton-zooplankton ecosystems and enhancing accumulation of photosynthetic biomass in low-nutrient oceanic environments.

Infection of phytoplankton by aerosolized marine viruses.

Marine viruses constitute a major ecological and evolutionary driving force in the marine ecosystems. However, their dispersal mechanisms remain underexplored. Here we follow the dynamics of Emiliania huxleyi viruses (EhV) that infect the ubiquitous, bloom-forming phytoplankton E.

Decoupling physical from biological processes to assess the impact of viruses on a mesoscale algal bloom.

Phytoplankton blooms are ephemeral events of exceptionally high primary productivity that regulate the flux of carbon across marine food webs [1-3]. 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 hinders the quantification of bloom demise and its regulation by biological processes [5, 6], which has important consequences on the efficiency of the biological pump of carbon to the deep ocean [7-9].