OceanKnowledge for everyone!

Former picnic peninsula in Ronton - now an isletIf you don’t know where Kiritimati Island is, just follow your finger down (south) from Oahu, Hawaii. Just before you hit the equator, there it is: The biggest coral atoll of planet Earth, inhabited by something between 7.000 and 10.000 people (the last census took place just a few months ago, but the numbers are not yet released). And this atoll sits right in the middle of the warm surface water masses that build up in the east and central Pacific during an El-Niño. According to NOAA data the waters around Kiritimati were up to 3°C warmer than average and the water level was about half a meter higher (sorry my friends of non-metric measuring systems – you’ll have to convert yourself as the internet here is too slow to even try the use of an online converter). What do these numbers mean to the ecosystem of the atoll and to the people living here?


Crumbling Seawall in RontonHigher water temperatures mean that the corals, which build the atoll and protect it against waves, are under stress. Stressed corals repel their symbiotic algae, but without them the corals basically starve. When the algae-free state lasts for several weeks or even months, the corals starve to death. I went scuba diving a week ago, and trust me, what I saw wasn’t pretty, despite all the colorful reef fish around. Many corals were bleached, many dead already overgrowing with green and red algae. I am no coral expert, but to my eyes the most abundant living thing was red coralline algae, covering the dead coral heads and branches and filaments. The good thing is that this type of algae actually cements the dead coral pieces and the rubble together, so that it doesn’t crumble as much as if the dead material was overgrown with green macroalgae. But still, the reef in this state is likely to break under pounding, high energy waves. When this happens the reef stops to act as a wave breaker for the island and the full destructive energy of the waves crashes on shore.

The high water temperatures further lead to high evaporation, formation of heavy clouds and rain, lots and lots of rain. The pre-climate change weather pattern here was dry season from May to October, rainy season from November through April. Thanks to climate change, the people on Kiritimati Islands experienced several years of drought until it started raining in January 2015. Just in the past two months, the heavy rains finally got less, which means it was raining for one year, much more and stronger than ever known. The streets were under water for most of the year. On an island where walking is the main means of transportation, it means walking ankle or knee-deep through water. Dirty water, as it combines the dirt from the flooded roads with the dirt from the flooded waste collection areas and the dirt from the pig pens. Little cuts or mosquito bites on feet and legs get easily infected, as I have seen especially true for kids. Huge freshwater or brackish water ponds form all over the island – an ideal breeding ground for mosquitoes. Luckily there was not dengue fever outbreak despite the number of flying pests. But even without infections and fevers, flooded roads make travelling on the island more difficult and the increased humidity is no friend of keeping food fresh and mold-free.

The result of too much rain: fresh or brackish water pond along the roadThe main cash flow on the island is produced by tourism, mainly fly-fishing tourism plus the odd surfers, scientists and journalists. Kiritimati Island is apparently the best saltwater fly-fishing ground in the world. Or so I was told. The fishing happens on or along the flats in the huge lagoon. But due to the elevated water level during this El-Niño, the tides were messed up. Flats didn’t fall dry anymore during low tide and the water flow patterns in the lagoon changed. In some areas of the lagoon, the rain cooled down the water temperature to below the usual, despite the warmer ocean water. All of that changes the whereabouts of the big fish. When heavy rain pounds the lagoon, the water becomes murky with silt from its bottom. Bad visibility is bad for fly-fishing, as the fish has to be able to see the fly above the water. Bonefish and Jacks are not to be found at the usual places, and if they are, they cannot see the flies. All of that makes the life of the fishing guides more difficult. After all, their livelihood depends on the number and size of fish the tourists catch (and release again – it’s all about the photo I was told).

And – not least of all – higher mean water levels also translate to increased coastal erosion. High tide is higher than usual and within the last few months annihilated some favorite picnic spots of the islanders. A lovely peninsula at the end of the village Ronton (speak: London) was one of them. Now it is an islet, which cannot be reached by foot or bike anymore. But as you can imagine, not only picnic spots are close to the sea, but also some houses. Formerly built sea walls are to low and disappear under and in the waves or are destroyed. Fundaments of houses are hollowed out and the houses tilt toward the sea. It would have probably happened eventually anyhow, but the high water levels and quite heavy storms and high waves in the last few months sure didn’t do anything to prolong the existence of those houses.

A wave crashed over this jetty and killed four menOn January 9th this year, another maybe El-Niño and climate change related catastrophe happened. During heavy weather and strong waves, one extremely high freak wave hit the island and the jetty, washing a cargo container, a car and four men into the sea. All four died. Locals had never seen such a high wave before, high enough to reach over the rather new jetty. They are blaming cyclone Ula for the bad weather generally and for the freak wave in particular. If Ula is to be blamed or not is hard to say, but for sure it was an extremely long-lived cyclone, lasting from late December 2015 to mid-January and travelling a vast distance in the southern Pacific, although it stayed about 4000 km from Kiritimati.

Currently the El-Niño seems to be subsiding. Due to the less than optimal internet connection I cannot check the NOAA El-Niño Website, but locally, the water level in the lagoon is slowly dropping and the rains decreased to normal rainy season conditions (which still means that the roof of my house is leaking and I sometimes fear the house plus me inside is going to be washed away in the downpours). According to some scientists from the NOAA El-Niño Rapid Response Program, who are measuring the local conditions daily, the surface water temperatures are still too high. But let’s hope that the siege by warm water is over and the island gets a breather until the next El-Niño hits.