The continued pressure to expand the exploration of natural resources in the past decades has increased the risk of environmental impacts with little understanding of ecosystem resilience. My research focuses on identifying chemical signatures that can be used as indicators of ecosystem change, from coastal to deep-sea demersal environments, including pelagic and benthic systems and their living biota.

One of the main challenges is to link physical, chemical, and biological components in large-scale ecosystems when little information is available. For example, the deep-pelagic is both the Gulf of Mexico’s largest habitat and least known, highlighted by the Deepwater Horizon oil spill, due to the extensive data gap that hampered the assessment of injury to the environment. Still, a decade after the spill, information regarding the source and weathering of organic matter and associated organic contaminants is mostly unknown. Organic contaminants can alter biological diversity and ecosystem functioning, therefore are key for linking long-term population dynamics and environmental stressors.

Assessing marine ecosystems functioning and health requires multiple tools.  My research applies different organic chemical analyses (e.g., fatty acids, aromatics) in combination with stable isotopes (e.g., carbon, nitrogen) to contrasting environments and biotic systems. My current projects cover three principal lines of research (for detailed information, check out the “Projects tab”):

• Sources, transport, and fate of chemicals on the ocean floor 
• Time-series analysis of toxic compounds in shallow and meso/bathypelagic fauna
• Chemical indicators of ecosystem health

Below are some of the analytical methods that I use in my research:

• Lipid Analysis: Molecular and isotopic composition of lipids in microorganisms and plants (Phospholipid fatty acids, n-alkane of leaf waxes) using GC-FID, GC-MS, GC-IRMS. Polycyclic aromatic hydrocarbons, hopanes, steranes/diasteranes, triaromatic steroids, pesticides, PCBs, PCPs (plastic additives, UV filters) in sediments, water, fishes, and marine invertebrates using GC-MS/MS-MRM analysis.
• Colorimetric Chemical Analysis: porewater (Chla, H₂S, NH₄⁺, PO₄^3-, NO₃^–, NO₂^–), and sediments (Chla, total phosphorus),
• Stable isotopes: Carbon and nitrogen in solid phase (¹³C,¹⁵N; Elemental Analyzer coupled to isotope ratio mass spectrometer),  and water (dD, ¹⁸O; integrated-cavity output spectroscopy); carbon and nitrogen metabolism (⁵N₂, ¹⁵NO₃^–, ¹³C-bicarbonate incorporation).

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