UL Lafayette researcher to use hyperspectral satellites to study phytoplankton in Gulf

Dr. Bingqing Liu, an assistant professor in environmental sciences at the University of Louisiana at Lafayette, will use advanced bio-optical experiments, hyperspectral satellite technologies and coupled modeling to study the dynamic world of tiny ocean organisms called phytoplankton in the northern Gulf of Mexico. Her research is being funded by a $927,000 grant from NASA’s Earth Sciences division.

Liu’s research aims to deepen the understanding of the present and future changes in phytoplankton assemblages in aquatic environments in response to changing climate and anthropogenic influences. She will also investigate its consequences in the biologic shifts and ecosystem functioning in northern Gulf of Mexico – a region that is standing in the frontline of environmental stressors.

Phytoplankton provide food and oxygen for many marine organisms, regulate the carbon cycle and climate, and support various ecosystem services, such as fisheries, water quality, and biodiversity.

“Knowledge of phytoplankton community structure is key to understanding complex earth science questions. This research represents an important step forward in the field of satellite oceanography, utilizing innovative hyperspectral technologies to study phytoplankton dynamics in optically complex coastal waters of northern Gulf, which has long posed formidable challenges for ocean color remote-sensing applications in this region,” said Liu. 

Phytoplankton are a diverse set of microorganisms, varying in cell shape, ecological functions and physiological responses to climate-related factors.

“One might question how satellites, orbiting hundreds of kilometers above Earth, can detect and differentiate tiny organisms in the water. The secret lies in the beauty of light fields within aquatic environments. Phytoplankton absorb and scatter light in distinct ways, altering the water's color and appearance – changes that hyperspectral satellites can capture from space,” said Liu.

These organisms serve as sensitive indicators of environmental changes, responding to variations in temperature, light, nutrients, pH and stratification. Phytoplankton-based food webs are vital to the productive fisheries in the Gulf, which face potential shifts because of rising temperatures. These shifts can lead to observable changes, such as smaller fish sizes in the Gulf.

“Studying the basic mechanisms and impacts of climatic factors on phytoplankton community composition and succession from space is important for understanding food web structure, higher trophic level production (e.g., fisheries), and biological shifts at the regional scale with a higher spatial and temporal resolution,” said Liu.

There is an increasing interdisciplinary interest in phytoplankton community dynamics in the northern Gulf of Mexico, where massive river input of nutrient-rich freshwaters leads to excessive richness of nutrients, harmful algal blooms and annual reoccurrence of bottom-water hypoxia events.

Using satellite technology to discriminate between phytoplankton species – toxic or non-toxic – is of paramount importance in harmful algal bloom monitoring. This capability enables early warning and effective mitigation of losses, fostering the development of resilience strategies for coastal communities near the Gulf, said Liu.

NASA received a total of 60 proposals, funding only 14 after a peer review panel evaluated each.