Since spring has officially sprung, I’ve been casting my mind back to warmer tides, tropical sunsets and the itch to get back out in the field putting science into action.
Last April, along with my fellow third year Environmental Geoscience students, I stuffed snorkels, pH probes, hiking boots and dive slates all into my backpack and flew across the Atlantic to Jamaica. Having looked forward to this moment for our entire degrees, we were pretty excited to say the least.
This was our opportunity to indulge in the balmy Caribbean sea surface temperatures and jerk cuisine, to meet turtles, corals, fish and rays up close and personal. This was our opportunity to put our oceanography knowledge to the test and learn real practical techniques that would be invaluable skills for years to come.
Where famous marine scientists such as Goreau and Hughes once stood, our fieldtrip soon followed in their physical, if not intellectual, footsteps, arriving in trepidation on the shores of Discovery Bay.
The land of (wood and) water
However, no sooner had we arrived at the marine laboratory situated on the northern coast of the island, we realised that there was indeed trouble in paradise.
Instead of the untouched pristine island of our dreams, we were met with sprawling tourist developments, extensive deforestation and a huge bauxite mine as our closest neighbour. Reality hit hard.
As we spent our first week heads down and snorkels up (with red necks to boot!) we conducted ecological surveys of the coastal ecosystem using quadrats and transects. Within minutes of our first glimpse below the surface, large swathes of green snotty algae stretching metres across the backreef confirmed that something was afoot. Our results showed that some areas had up to 50% macroalgae cover, thought to be smothering coral reef growth which would likely affect the reef health overall. Even large swarms of algae-munching urchins were no match for this algal tide. Our sprawling underwater metropolis lay quiet.
To find out what was going on, next we looked to geochemistry to give us some answers. Hanging off the side of our boat we took water samples from the surface ocean across the entire bay area and hauled them back up to the wet laboratory onshore. A mosquito-rich humid haze greeted us within the lab, where we battled our thirst to jump straight back into the cool ocean at any opportunity. However, it was to be titrations, reductions and patience that won over the next days. Slowly we began to build up a picture of the unusually high nitrogen, phosphate, calcium, silicate and other nutrients in some areas of the bay.
This got us thinking. Tropical coral reef systems are highly productive environments that require lots of nutrients to sustain their incredible diversity of life. As such, they are usually oligotrophic, meaning they show low levels of nutrients in the water, as every organism desperately squeezes as much as they can out of the water.
These high levels of nutrients were therefore worrying. Could they be related to the smothering algae entangling us as we swam?
Maybe the hydrography could shed some more light for us. To find out the structure of the water column we lowered a Conductivity Temperature Depth probe into the water along transects across the bay, and released an Acoustic Current Meter onto the water surface. These investigations would tell us the patterns of circulation within the bay and give us an idea of where nutrient rich water might be coming from.
Lo and behold our results showed evidence that freshwater was being added to the bay, but from where? Jamaica is primarily composed of limestone that has been highly weathered over thousands of years to form a porous, pockmarked landscape with deep caves and underground tunnels leading to the sea. It therefore seemed possible that nutrients were being added from inland, transported through these hidden channels and dumped into the sea.
After a week spent coast-side, with only a small respite at the beach shack barbeque (well, we had to have some breaks!), we set off inland to explore the jungle interior and see what Jamaica’s geological history could tell us. Taking river samples, hiking through primordial forest to isolated sink holes (a refreshing find!) and being thrust into the desolate landscapes of the local bauxite industry, we compared the water chemistry we found upstream with what we’d seen in the sea.
Sadly, our worst fears were, indeed, confirmed. It seemed that fertilisers from inland agriculture were being transported, along with artefacts of igneous and sedimentary geology, through the porous limestone and into Discovery Bay. The resulting changes in the reef ecosystem and loss of corals was devastating.
It was a humbling realisation. The work we had undertaken in Jamaica immersed us in some beautiful landscapes and taught us crucial skills. However, the realities of industrialisation, expansion of tourist developments and a move away from traditional fisheries, highlighted the stark effect on the health of the coral reefs.
I stepped back on the plane exhausted, eyes opened, and more motivated than ever to use the knowledge and skills gathered from my degree to do what I can to protect these beautiful ecosystems and the communities which depend on them for survival. If paradise was there before, maybe we can find it again.