Author: dls00012

Insights into the red algae and eukaryotic evolution from the genome of Porphyra umbilicalis (Bangiophyceae, Rhodophyta)

Dr. Senjie Lin and his current and former Ph. D. graduate students, Brittany Sprecher and Yunyun Zhuang, engaged in an international collaboration to sequence Porphyra umbilicalis’ nuclear genome. Their efforts revealed how the red algae has been able to thrive in the harsh intertidal zone under exposure to high UV radiation, changing temperatures, and severe osmotic stress and desiccation for more than a billion years. Porphyra umbilicalis belongs to an ancient group of red algae, Bangiophyceae, and is a valuable human food source.

The team’s analysis found that P. umbilicalis has a small set of cytoskeleton motor proteins (explaining why red algae are smaller in size when compared to most multicellular lineages), several cellular mechanisms to cope with the stressful environment, and a high capacity for nutrient uptake and utilization.

Major support for the genome sequencing was through a contract with the U.S. Department of Energy’s Joint Genome Institute, sequencing analysis was supported by a National Science Foundations Research Collaboration Network grant, and the project was led by Dr. Susan Brawley at the University of Maine. The findings are published by Proceedings of the National Academy of Sciences.

Porphyra umbilicalis
(Yuanyu Cao/University of New Hampshire)

Jessica Hinckley receives a 2017 Summer Undergraduate Research Fellowship (SURF) award

Sophomore marine sciences student Jessica Hinckley is the recipient of a summer undergraduate research fellowship (SURF) where she will be working on a pioneering carbon dioxide time series in Long Island Sound with Prof Penny Vlahos. Jessica will be investigating trends and responses of dissolved carbon dioxide and oxygen under various temperature and wind conditions.

Image credit Julia Kendzierski.

NOAA announces funding for research on sand lance

The Ocean & Atmospheric Research program (OAR) of NOAA and Sea Grant just announced the winners of its most recent round of research funding to better understand the consequences of ocean warming and acidification on key marine resources in U.S. Northeast coastal waters. Hannes Baumann and collaborators were happy and proud to learn that their proposed work on the climate sensitivity of Northern sand lance (Ammodytes dubius) was one of the four projects selected for funding. This is particularly good news for Chris Murray, who for his PhD can now expand his experimental rearing expertise to this important species.
This project will be conducted collaboratively with colleagues from NOAA (David Wiley), USGS (Page Valentine), Boston University (Les Kaufman), and Woods Hole Oceanographic Institution (Scott Gallager).

You can read the official announcement as it appeared on 6 September 2016 on NOAA’s News site

DMS graduate student Vena Haynes awarded EPA STAR Fellowship

Vena Haynes was recently awarded the EPA STAR Fellowship for her environmental toxicology research with Dr. J. Evan Ward. Vena is a PhD student in the UConn Marine Sciences program, where her research is focused on the effects of environmental pollutants on marine food webs. Manufactured nanomaterials are entering aquatic environments from product usage, industrial waste, and wastewater treatment plant effluents. Specifically, titanium dioxide nanoparticles found in consumer products, such as sunscreen and personal care products, can be toxic to organisms and its toxicity can increase with exposure to light. Very little research has been done on the effects of these nanoparticles in the marine environment with exposure to natural light. The objective of this project is to examine the effects of titanium dioxide nanoparticles on ecologically important food web grazers that inhabit coastal waters, using environmentally relevant experimental conditions. This work will aid in the development of safer nanomaterials and help predict impacts on grazer populations and organisms that rely on grazers for food (primarily fish).



Dimethylmercury in the Ocean: Where does it come from?

press release

The accumulation of mercury, primarily as methylmercury, into fish and seafood consumed by humans is a global health concern. Recent research has highlighted the potential sources of methylmercury in the ocean, and demonstrated that it can be formed by microbial methylation of inorganic mercury. However, one of its sources could also be the degradation of dimethylmercury. There has been little study, however, of the formation pathways of dimethylmercury in the ocean, even though it has been detected in surface and deep waters.

A new paper published in Nature Scientific Reports (  by researchers in the Department of Marine Sciences (DMS) at the University of Connecticut has shed light on potential pathways for its formation, and suggests that dimethylmercury may be formed by abiotic processes from methylmercury. These studies were carried out by research scientist Sofi Jonsson and graduate student Nashaat Mazrui in Robert Mason’s laboratory. Their experiments show that dimethylmercury can be formed in the presence of iron sulfide particles, as well as other metal sulfide particles, via the reaction of two methylmercury molecules bound to the particle surface. The products of the reaction are dimethylmercury and inorganic mercury, which is precipitated onto the surface. In addition, these reactions were also shown to occur in the presence of organic compounds with reduced sulfur groups (thiols). The proximity of the bound methylmercury molecules determines the rate of the reaction, and the reaction is more favorable with organic compounds with multiple thiols.

“The reaction pathways are highly favorable and we were able to show that the reactions occur under a wide variety of conditions” said Jonsson “and our calculations suggest that these mechanisms could account for much of the dimethylmercury in the ocean.”  Mason commented that recent estimates suggest that about half the methylmercury formed in the upper ocean is from the degradation of dimethylmercury, and that further studies are needed to examine the importance of the proposed pathway compared to other mechanisms. The authors suggest that such reactions could be occurring within particles in the ocean, or within microbial cells. It is also possible that the reactions could occur on the surface of nanoparticles and Mason’s group, in collaboration with Jing Zhao at the Department of Chemistry (UConn), will further explore this possibility by studying these reactions on both natural and manufactured nanoparticles, and the factors that influence the reaction rate.

Early measurements of dimethylmercury in the equatorial Pacific Ocean were made by Jon Kim and Robert Mason, while graduate students at DMS, and many other studies have reported its presence in ocean waters since then.  One place where dimethylmercury has been measured in higher concentrations is the Arctic and a recent modeling paper by researchers at Harvard suggests that a large fraction of the methylmercury produced in the Arctic is converted to dimethylmercury. Although the paper published from researchers at Harvard does not propose a mechanism for this reaction, it could involve the reactions proposed on particle surfaces in the water or sediment. Jonsson will later this summer participate in a research expedition in the Arctic onboard the Swedish icebreaker Oden which will allow her to test some of the ideas about formation and stability of dimethylmercury in this region.

press release

Airborne Campaign to Map Coral Reef Ecology is Underway

Dr. Dierssen, professor in Marine Sciences, is participating in a new NASA-funded project to conduct airborne mapping of coral reef ecology as part of the COral Reef Airborne Laboratory (CORAL). Her team will collect field data to validate the remote sensing observations collected in Hawaii, the Mariana Islands, Palau, and the Great Barrier Reef. For each reef, the spectral imagery will be processed to assess the distribution of coral and rates of coral primary productivity and calcification. A recent Nature article describes the project: