Iron limitation in diatoms impairs viral infection

April 10, 2021

In a recent study published in Nature Geosciences led by Chana Kranzler from the Thamatrakoln Lab at Rugers University, we examined how iron limitation in diatoms may affect viral infection.  Molecular datasets used in the study were derived from incubation experiments led by members of the Marchetti lab during the IrnBru cruise in the California Upwelling Zone in 2014 and a Line P cruise in the Northeast Pacific in 2015. The study found an interesting ecological trade-off in how growth limitation by low iron availability may result in diatoms being less vulnerable to viral infection by slowing down mortality and reducing viral replication.

Impaired viral infection and reduced mortality of diatoms in iron-limited oceanic regions

A Nature Geosciences news and views article about the study is available here.

New publication in mSystems!

March 30, 2021

Chaetoceros decipiens

Our new publication led by former Master’s student Rob Lampe was recently published in mSystems.  In this study we simulated the upwelling conveyor belt cycle (UCBC) to examine how a common diatom and coccolithophore originally isolated from the California upwelling zone respond to changes associated with the cycle.  In addition, we examined the effects of iron-limitation on how these two phytoplankton species cope with the UCBC.  Our findings show that the diatom Chaetoceros decipiens is particularly well-adapted to upwelling cycles.  Co-authors include current graduate student Johnson Lin and former undergraduate researcher Gustavo Hernandez.

 

Representative Diatom and Coccolithophore Species Exhibit Divergent Responses throughout Simulated Upwelling Cycles

Carly defends her Ph.D. thesis!

Oct. 29, 2020

Congratulations to Dr. Carly Moreno who successfully defended her Ph.D. thesis titled ‘Coupled molecular physiology and ecology of Southern Ocean diatoms in response to shifting iron and light availability’. Carly’s research investigated how polar diatoms acclimate and adapt to varying iron concentrations and light levels, providing new insights into how phytoplankton communities may shift in rapidly changing polar environments.  The punchline is that not all diatoms are created equal!

 

New publication in Environmental Microbiology!

September 19, 2020

Our new publication led by former Ph.D. student Weida Gong was recently published in Environmental Microbiology.  In this study why compare and contrast multiple approaches for taxonomic identification of eukaryotic phytoplankton in the Neuse River Estuary and examine the environmental factors that influence phytoplankton composition.  Our findings provide additional support and validation for the integration of environmental genomics into coastal water quality monitoring programs.

Phytoplankton composition in a eutrophic estuary: Comparison of multiple taxonomic approaches and influence of environmental factors

New publication in Limnology and Oceanography!

February  7, 2020

Our new publication led by Ph.D. candidate Carly Moreno was recently published in the journal Limnology and Oceanography.  In this study we examine the interactive response of the Southern Ocean diatom Fragilariopsis kerguelensis to changes in light and iron.  The transcriptome analysis reveals mechanisms that may underpin the ecological success of this diatom in low iron and light environments, highlighting the important role of diversified photosynthetic isoforms, iron acquisition, unique detoxification mechanisms of reactive oxygen species, and metabolic shifts in amino acid recycling and carbon metabolism.

Interactive effects of iron and light limitation on the molecular physiology of the Southern Ocean diatom Fragilariopsis kerguelensis

Weida defends his Ph.D. thesis!

August 15, 2019

Congratulations to Dr. Weida Gong who successfully defended his thesis titled ‘Characterization of the taxonomic composition and physiological status of natural eukaryotic phytoplankton communities’. Weida implemented cutting-edge molecular approaches to interrogate plankton in their natural environment. He is now ready for a job with the FBI!

New publication in ISME Journal!

August 22, 2019

Our new publication led by former Masters student Rob Lampe (now at UCSD) was recently published in ISME Journal.  In this study we investigated the response to deep water amendments by natural phytoplankton communities in the Sargasso Sea.  Using a combination of physiological measurements and metatranscriptomics, we found that diatoms, which are the primary responders following nutrient enrichment, elicit a distinct molecular response that underlies their rapid increase in growth compared to the other dominant phytoplankton groups in the nitrate-depleted ambient surface waters.

Strategies among phytoplankton in response to alleviation of nutrient stress in a subtropical gyre

Also check out the behind-the paper blog post Rob wrote about the study here.

New publication in PNAS!

December 15, 2018

Our new publication led by former Masters student Rob Lampe (now at UCSD) was recently published in the journal Proceedings of the National Academy of Sciences.  In this study we show that there are multiple ways in which diatoms can store iron and that ferritin-containing diatoms such as Pseudo-nitzschia may have a competitive advantage when iron is delivered in pulsed supplies.  Our findings suggest that in areas of the ocean where iron concentrations may decline due to climate change, diatom composition could shift to ferritin-containing diatoms.

Different iron storage strategies among bloom-forming diatoms

A brief write-up about our study can be found here.

New publication in Environmental Microbiology!

February 19, 2018

Our new publication led by graduate student Weida Gong was just published in Environmental Microbiology. In this  study we examine the spatiotemporal dynamics of phytoplankton using gene expression analysis within the Neuse River Estuary.  We provide compelling evidence for the utilization of such ‘omic techniques as useful tools in water quality monitoring programs.

Eukaryotic phytoplankton community spatiotemporal dynamics as identified through gene expression within a eutrophic estuary

New publication in Journal of Phycology!

May 10, 2017

Our new publication was published online in Journal of Phycology Early View.  In this study we have developed a molecular indicator to determine the iron status of Pseudo-nitzschia within natural diatom assemblages using gene expression.  As part of this study, we have created an online tool to calculate the Pseudo-nitzschia Iron Limitation Index (ILI) from metatranscriptomic sequence data sets.

Development of a molecular-based index for assessing iron status in bloom-forming pennate diatoms

The Pseudo-nitzschia ILI Calculator is available here.