Efforts are being put into developing and applying scales and indices for eco-anxiety.

Alt: elmo from sesame street standing in front of a wall

continuing to search for a name for oil

The first female president of the Magic Circle, Megan Swann, now performs environmental magic, creating spellbinding tricks to inspire children and adults to act more sustainably

YouTube video by Doomer Optimism

Whilst much of the country is wilting under the unprecedented summer heat and praying for rain, I was hoping for the dry weather to persist for just long enough for me to complete my August field surveys in Cumbria. It would have been ironic in the extreme if, after all this dry weather, my fieldwork had to be postponed because of high flows. Having argued in this blog that algal proliferations in rivers are as much due to the weather as to nutrients (see: “The greening of our rivers (2) …”, “Understanding verdant rivers (V)” and “Green days …”), I saw this period as an extended natural experiment and last week was my opportunity to harvest this year’s data. The streams and lakes of western Cumbia offer a good template for reflecting on the role that the weather plays in boosting algal growth because they are all located in a region without significant urban centres and agriculture is relatively unintensive, meaning that nutrient concentrations are generally low and we have to look to other factors to explain patterns in algal growth. What did I find? First, the three lakes that I visit – Crummock Water, Ennerdale Water and Wastwater – all had low biomasses of benthic algae (those attached to surfaces). Primary production in these habitats is dominated by phytoplankton which are extremely efficient at hoovering up the scant nutrients, leaving little for the attached algae to utilise. The larger stones at the margins often have a fine “stubble” of filamentous algae (typically _Spirogyra_) but the overall quantities are quite low. **Boulders at the margin of Wastwater showing the typical “stubble” of green algae. The photograph at the top of the post shows the River Irt about 5 km below the outfall from Wastwater.** The situation, however, changes almost immediately below the lake outfalls, where filamentous green algae covered much of the river bed at six of the seven sites I visited. The picture at the top of the post, from the River Irt, is typical of what I saw across the region. Those rivers and streams that are not downstream of lakes showed a variation on this theme. Superficially, the river beds looked to be in good condition, without the conspicuous growths of green algae that I had seen elsewhere. However, the rocks were slimy to the touch and measurements suggested that prolific diatom and Cyanobacteria growths were responsible. There were patches of green algae in some of these rivers and streams, but these generally covered relatively little of the stream bed. The difference between the lakes and their outfalls is most likely due to the switch to circumstances where the supply of nutrients, though low, is constantly replenished and the suspended algae that thrive in the lake are washed downstream and out of contention. Add to this the perfect growing conditions – warm water and plenty of sunlight – and the algae on the stream bed can easily outstrip the best efforts of invertebrates to graze on this largesse. The difference between rivers downstream of lakes and those not connected to lakes is a little harder to explain. It is not a difference in quantity so much as in the types of algae that predominate. The smaller streams tend to be more shaded, but I don’t think that this, alone, can explain the difference. I suspect that it may be something to do with the composition of the grazers, but I have no evidence at this stage. **The bed of Croasdale Beck in August 2026. Just a few kilometres from the location where the photo at the top of the post was taken but, in this case, the algae are better camouflaged and, as a result, more likely to be overlooked.** A quick scan back through my data suggests that there has been a steady upward trend in the quantities of algal biomass that we measure since we started these observations in 2013. It is a noisy trend, because riverbeds are patchy and the British summer is unpredictable (we recorded less in the wet summer of 2024, for example), but it is significant. Adapting the terminology I introduced in “Understanding verdant rivers (V) …”, these streams are showing “meteorology-induced summer euphytic condition” (“meterology” rather than “climate” because this is a response to a particular local manifestation of the climate) and I suspect that it is very widespread this year. In many parts of the country (though not in this part of the Lake District), it will exacerbate the effect of nutrients, so maybe it is better to think in terms of a broad “syndrome” rather than sticking to the metaphor of disease too strictly. We are still only in early August, so there is still time for the weather to break and enough rain to fall to flush most of these algae downstream. Shorter days might start to limit the amount of sunlight available to fuel photosynthesis, but the lakes act as huge heat pumps, keeping the rivers they feed a few degrees warmer than other streams during the autumn. It means that I’m already curious to see what will be growing at these locations in October, when I next visit. After visiting this group of lakes and streams regularly for over a decade, I’ve got a good idea of what to expect but also know to expect to be surprised. **Training up the next generation …** Some other highlights from this week: **Wrote this while listening to:** Janis Ian, whose music featured in _Chuck Chuck Baby_ (see below). **Currently reading:** a collection of John Mortimer’s _Rumpole_ short stories **Cultural highlight:** Brilliant 2024 low budget romcom _Chuck Chuck Baby_ , available on the iPlayer.. **Culinary highlight:** … or highlights (plural) due to the steady flow of Sichuan home cooking from our kitchen whilst our daughter-in-law is staying with us. ### Share this: * Share on X (Opens in new window) X * Share on Facebook (Opens in new window) Facebook * Like Loading... ### _Related_

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