The ocean has always been a source of mystery and fascination to me. It was a scene of tranquillity and natural beauty, but little did I know, the air was also alive with invisible molecules performing a crucial dance. Behind the blue oceanic color, the sound of waves, teeming with life, it holds mysteries that urge my curiosity. Among the molecules, there is isoprene, a compound unfamiliar to most, yet essential to the environment. It is a biogenic volatile organic compound (BVOC) with chemical formula C5H8. It is a colorless, highly volatile liquid at room temperature and is one of the simplest hydrocarbons.

The first time I heard about Isoprene, I wondered, “What on earth is this gas about?”. My supervisor spoke about the significance of phytoplankton, the tiny plant-like organisms that form the base of the marine food web. She mentioned that these microscopic creatures are the ones who released isoprene into the atmosphere. Isoprene is a hydrocarbon that is commonly associated with terrestrial plants, which emit it to protect themselves from heat stress. In oceanic environments, isoprene is mostly emitted by phytoplankton “Yeay!! I am free from the heat stress”- phytoplankton. They act as the major producers of isoprene in the marine environments. These tiny organisms, drifting in the sunlit upper layers of the ocean, release as a byproduct of photosynthesis.

My journey into the world of isoprene in marine ecosystems began while doing my research in Port Dickson, Negeri Sembilan. As I dug deeper into the scientific literature, I discovered that isoprene has a complex relationship with the atmosphere. Once released, it interacts with other compounds, influencing air quality and climate. During the day, isoprene can react with pollutants like nitrogen oxides to form ozone, a key component of smog. At night, it can contribute to the formation of secondary organic aerosols, tiny particles that affect cloud formation and, consequently, the Earth's climate. On the surface, the ocean appeared serene, its waves gently lapping against the shore. However, beneath this tranquillity lay a complex and dynamic environment, where tiny organisms and phytoplankton performed chemical feats that had far-reaching implications.

We started by collecting water samples from different ocean regions, using a low-cost sensor called Aquasense to measure in-situ parameters. This sensor also be called “Ah Seng” as its nickname and indeed it is my best buddy throughout my research study about isoprene together. Ah Seng can measure in-situ parameters like isoprene, water temperature, turbidity, pH, dissolved oxygen, and Total Volatile Organic Compound (TVOC). It is important to have in-situ parameters as isoprene is highly reactive and has a short lifetime. Time travel from our study sites to the lab could have different readings of all the parameters involved.

Moreover, as phytoplankton is the main driver of isoprene, we observed what genus involved and dominated in Port Dickson coastal waters. The first time I looked through a microscope at a sample of concentrated phytoplankton, I was awestruck. Diatoms dominated this water body in our regions. These tiny, almost invisible organisms were the lungs of the ocean, their photosynthetic activity a vital part of Earth’s life support system. We analyzed our samples and found that isoprene emissions varied significantly across different regions and seasons, influenced by environmental factors like water temperature, solar radiation, wind speed, chlorophyll-a concentrations, and nutrient availability. Chlorophyll-a could define the biomass of phytoplankton on the surface of the oceans of the study areas. For example, in nutrient-rich upwelling zones, where cold, deep waters rise to the surface, phytoplankton blooms are accompanied by the production of isoprene.

We need to study isoprene as once it is released into the atmosphere, isoprene undergoes a series of chemical reactions, contributing to the formation of second aerosols. These formations play a crucial role in cloud formation, influencing the weather patterns and climate. Marine isoprene emissions therefore have a direct impact on the earth’s climate system, a connection that highlights the intricate interplay between ocean and atmosphere. The dual role of isoprene as both a climate influencer and a potential pollutant underscores the delicate balance of natural processes and human impact. After all, it is fascinating to think that a molecule emitted by trees could one day help us reduce our environmental footprint.