A lake dries up and only a few ponds remain, with a lot of fish mortality. Warming Brazilian lakes have a huge impact on food security and on the economy. This ratio in various Amazonian lakes is not only due to temperature, but also due to lack of oxygen or even the lake drying up, impacting entire ecological chains and the populations that depend on these chains. WATCH & READ Overheating caused mass deaths of dolphins, transcript follows-[O Liberal Description Referência de jornalismo na Região Norte do Brasil, o oliberal.com faz parte do Grupo Liberal. É o portal de notícias do jornal O Liberal, de Belém do Pará. Acompanhe nossa programação. On YouTube from Brazil since 2016]
So, in recent years, we've had a series of extreme events here in the Amazon, especially extreme droughts, which have had an unprecedented impact on ecosystems and riverside and indigenous populations along the Amazonian rivers. And during these events, one process caught our attention, which was the warming of the waters.
So we noticed very high water temperatures in some lakes that we were closely monitoring, especially Lake Tefé and other lakes in Central Amazonia, temperatures as happened in Lake Tefé, and that is a temperature that goes beyond the thermal tolerance capacity of many aquatic animals, such as fish, dolphins, and others. So, starting from this alarming observation that we've had since about the warming of the lakes, we thought about advancing this study and providing answers about what was happening and increasing the scale. Not just looking at the few lakes for which we had field data, but looking with satellites at a larger scale, looking at many other lakes and answering what is happening to Amazonian lakes.
And the answer is: something very alarming is happening. We have had a generalized warming of Amazonian lakes, following global trends of lake warming, right? "beyond the thermal tolerance capacity of many aquatic animals"
So we estimated a temperature increase per decade, but that culminated during extreme events such as droughts at much higher temperatures, heat waves in the water. We usually talk about heat waves in the air, but this time we are also seeing heat waves in the water with very extreme temperatures.
In the Amazon, everything is connected, right?
So, when we talk about fish dying from excessive temperature or even about dolphins, which are top predators, dying, we are talking about the impact on the entire ecological chain and the populations that interact and depend directly on these chains. Fishing is the basis of the economy of the river Amazon, and of the Central Amazon. So, it's the basis of the diet, right? The main source of protein. Yes, it's fish.
When we see the impact of this ratio, right, of fish mortality in various Amazonian lakes, not only due to temperature, but also due to other factors, such as lack of oxygen or even the lake drying up, the lake has nowhere for the fish to go and they end up dying. We're talking about a huge impact on local populations, a huge impact on the food security of these populations.
So, we have many reports distributed throughout the Amazon. Here in Pará we saw many reports. For example, we have a study with partners from Ufopa in Santarém, at Lago Grande in Montealegre. It's a tragedy that has happened there in recent years.
Almost the entire lake dries up, and only a few ponds remain, with few fish and a lot of mortality. So, we're talking about a huge impact, not only, as I said, on the food security of the populations, but also on the economy, because those who depend on it, the fishermen who depend on these resources for their daily lives, are left without resources. So it's very alarming, and we have to think about solutions, we have to think about ways of adapting and seeking solutions to support these populations that have become increasingly vulnerable to these crises.
We studied with satellite imagery, we studied lakes distributed across the entire Central Amazon, from the middle Solimões, which we call the Amazon region, down here in the Santarém and Monte Alegre region and further down to the lower Amazon River. So, we looked at a whole distribution of lakes, right, in the Central Amazon, which are quite representative of Amazonian lakes and which also converge with the trends that we have seen on a global scale, of a generalized warming of lakes, and which during extreme events make temperatures even higher. at based on these methodologies that we have been developing in recent years, right, to monitor water temperature by satellite the PBIOMas Água, especially together with WWF Brazil, they launched an online platform, right, to monitor the water temperature of the Amazonian lakes, right?
So, mostly the same lakes with some additional ones, but it's an idea to look at a larger scale and bring answers in real time about what is happening with these lakes.
Water temperature has proven to be a key variable for us to understand what has happened in recent years, right? And then from satellites, we can have this understanding on a broader scale and be able to provide an answer. Are the lakes warming up again when a new drought comes? Every year we have the dry season of the rivers. That's natural. The problem is when this dry season becomes much stronger than normal, when an extreme drought comes.
After years of a lot of hardship, of two tragedies in sequence, we didn't have an extreme drought, and the temperatures didn't rise as much as in those years. So, having platforms of this type, monitoring strategies that allow us to provide real-time answers is very important.
But it's also important to point out that satellites don't provide all the answers we need. We need to be in the field and we need to have long-term monitoring strategies in the territory, because by satellite we still can't see much.
The animal mortality we can't see by satellite or the value of the fact that the water temperature is arriving, the satellite still has some difficulty in estimating. So, we need to have new ways, new monitoring strategies on the ground, in the territory, so that we can over the years understand, monitor and bring answers about what the climate emergency is bringing to the lakes of the Amazon.
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