Hi, my name is Mengli Chen, and my Chinese name is 陈梦立.
I am a research fellow at Tropical Marine Science Institute, National University of Singapore. I work in the area of chemical oceanography. I am particularly interested in the marine environment changes through time. The ongoing global warming is expected to alter the marine environment in the tropical surface ocean, hence affecting many marine species that human depend for daily subsistence.
I use natural archives like corals; investigating their chemical compositions and isotopes; and reconstructing the environment in which they lived in. Through paleoenvironmental reconstruction, I aim to understand the processes in transport/transform material through the ocean. The knowledge on chemical cycling will subsequently feed into strategies, practices in solving take real-world issues.
I'm currently working on these few projects:
Ammonia bunkering: environmental readiness
As we embrace ammonia as a viable alternative marine fuel, it is crucial to be prepared for its rippled environmental impact, in case of both day-to-day operations, and under disastrous cases like accidental release to the sea. As ammonia is so much ready to be taken up by algae as food, too much ammonia will likely entail excessive growth of algae, namely algal blooms. In these cases of blooms, the overwhelming growth and death of algae will consume a significant amount of oxygen, leaving other sea creatures suffocated. These algal blooms will also produce large amounts of organic matter that impact the coastal water quality. Lastly, some algal species produce dangerous toxins that can be harmful to aquatic and human life.
At Tropical Marine Science Institute, we take on the challenge of assessing the environmental impact of ammonia bunkering, though our multi-disciplinary research team and active links with academia, agencies, and industry. We aim to play a strong role in predicting the environmental aspect of ammonia bunkering in the busy, multi-used, and beautiful Singapore seascape.
Nitrogen isotopes in corals
The nitrogen isotopes provide insightful information on the efficiency of nutrient utilization, change in nutrient source; and therefore a powerful tool understanding marine nutrient cycling. I am investigating the change in trophic state in the western South China Sea from Little Ice Age to present using a 500+ year coral. I'm also working on the environmental implications of chemical fertilizer usage to coral reefs using a few corals from Bali.
Marine Pb cycling - boundary exchange
Exchange of chemical species and matter at ocean boundaries influences the composition of seawater, and is an important process affecting biogeochemical element cycling involving interactions between the atmosphere, hydrosphere, geosphere, and biosphere. Within the ocean, the cycling of lead (Pb) has a long-standing paradox: global-scale studies on the deep-sea sediments indicate a significant fluvial/boundary Pb input (source), whereas most of the new work identifies coastal areas as sinks of Pb. Thus, the ocean Pb balance is incompletely specified both prior to and after the commencement of the Anthropocene. This uncertainty limits our ability of using Pb isotopes for source apportionment and muddles our interpretation of climate-weathering feedback in Earth’s history.
Here, systematic quantification on the processes and budgets remains scarce. We now have shown that the adsorption-desorption exchange of lead (Pb) between the particulate and dissolved pools at ocean boundaries accounts for about 30-40% of Pb input into the ocean before the Anthropocene, which finally resolves the paradox of imbalanced natural sources and sinks of Pb in the ocean. With Pb as an example, our study adds a crucial piece of evidence to the importance of boundary exchange in marine element cycling.
P in coral skeleton
The phosphorus (P) in coral is of great potential as it may directly link to thenutrient budget in seawater. Long-term monitoring of seawater nutrient isextremely sparse and therefore the coral proxy could fill in the gap. To date,the P in corals has shown encouraging correlation with seawater phosphate.However, due do the complicated biological roles of P, especially the roles ofinorganic and organic P in corals, the incorporation mechanism is still largelyunknown. To fill in the gap, I am trying to separate the inorganic and organicphosphorus in the coral and calibrate them with seawater phosphate. I hope topropose P in corals as a nutrient proxy so that we can better access thenutrient budget in the seawater through coral reconstructions.