EO Detective ID PL1-0707-TJ-OCcci
What do you work on?
I now work on a global scale to try to improve our understanding of phytoplankton in the oceans. Phytoplankton are microscopic plants that are responsible for half the oxygen we breathe. These tiny organisms also play an important role in the global carbon cycle, respond rapidly to changes in local conditions and are remarkably diverse. Some produce blooms that can be seen from space and double their numbers in a single day, some protect themselves with intricate silica constructions and some produce dangerous neurotoxins that can enter the food chain and cause mass mortality. We can detect and measure them by how they change the transmission of light at the ocean surface. But the oceans are huge and phytoplankton have a short life-cycle so the only way to see them on a global scale is to use satellites.
How did you come to be an EO Detective?
I have always been inquisitive about how things work and interested in the details of the world we inhabit. I studied a mix of Maths and Sciences at A-level and then went on to complete an Earth Sciences degree at Oxford University. Earth Science is a fusion of the main branches of science (physics, chemistry and biology) and gives a wonderful insight into the processes occurring across the world at all scales from the microscopic to the inter-planetary, from seconds to eons. The oceans of the world currently cover two-thirds of the surface of the globe and are therefore a major component of the ‘Earth system’. I began to specialise in biological oceanography towards the end of my degree. My PhD focused on the dynamics of phytoplankton in the Arctic.
What does the image show?
This plot shows the primary productivity of oceans across the world in May 2004. The figure is a measure of how much carbon is taken from the ocean and atmosphere for every square metre of ocean each day. I created a sequence of these for the Transboundary Water Assessment Program by combining a model of how phytoplankton photosynthesise with input data on light and phytoplankton chlorophyll concentrations from satellite-based sensors.
How is the data you use collected?
A number of satellites are dedicated to the observing the oceans. Those that make measurements in the visible part of the electromagnetic spectrum are often referred to as ‘ocean-colour sensors’. Some sensors, such as SeaWiFS, MODIS and MERIS are polar orbiting satellites that can provide data for the whole globe. There are also geostationary sensors (e.g GOCI) that produce more frequent data but cover a limited region. Some of the sensors on ESAs Sentinel satellites also give us data about ocean colour.
What’s the best thing about your job?
One of the things I relish most about my work is that I never stop learning. The field of ocean-colour is constantly developing and growing as new discoveries are made. Improvements in the performance of Earth Observation sensors and computer processing/modelling power are providing us with a wealth of data to understand and interpret. I also enjoy the fact that ocean science is global, meaning I get to meet and converse with a diverse group of people across the world as part of my work.
Tell us about your favourite image of the Earth from space
Van Gogh From Space is the name of a Landsat image of the Baltic Sea around Gotland. The image is wonderful because not only does it resemble The Starry Night but it also gives a wonderful sense of perspective. The island in the middle of the image is about 90 miles long and the phytoplankton highlight the scale of the ocean currents in the area. Yet we can sill clearly see a human signature: ships leave clear (dark) lines in the sea and you can spot the straight, pale con-trails of planes. So, as well as showing the dynamic nature and beauty of the oceans, this image is a wonderful illustration that, although we are tiny compared to the Earth we have a clear influence upon it.
What do you do in your spare time?
I spend a lot of time in front of a computer (processing and interpreting data) so I try to keep active in my spare time. I enjoy cycling, hiking martial-arts and surfing.