Nutrient supply is an important determinant of N fixation rates in pelagic cyanobacteria. In shallow aquatic ecosystems, benthic primary producers can affect nutrient release from the sediment to the pelagic zone, yet the relationship between benthic primary producers and pelagic N fixation is not well understood. Here, we explore the effect of benthic primary producers on benthic nutrient fluxes and pelagic N fixation rates i...

Ecosystem engineers impact ecosystems by changing the physical environment in which species interact. In Lake Mývatn, Iceland, larvae of the midge Tanytarsus gracilentus function as ecosystem engineers by building tubes in the sediment that solidify the benthic surface and create a 3-dimensional structure on which microalgae can grow. To assess the ecosystem-scale effect of midge engineering, we took advantage of the natural h...

Organisms that move across ecosystem boundaries can create resource gradients in adjacent ecosystems. Midges that emerge from Lake Mývatn, Iceland, are deposited as nutrient-rich carcasses on land, and this generates a nutrient gradient from its shoreline. We contrasted the distribution and photobiont characteristics of two lichen species, Nephromopsis cucullata and Peltigera leucophlebia, in a lava field adjacent to Mývatn al...

Inorganic nutrients can vary over space and time in lakes due to abiotic and biotic factors. To understand the drivers of spatial variation in nutrients in shallow Lake Mývatn, Iceland, we mapped dissolved inorganic and organic nitrogen (N) and phosphorus (P) concentrations in benthic (interstitial) and pelagic zones in summer 2021 during a lake-wide pelagic cyanobacterial bloom and in spring 2022 when there was no cyanobacter...

The community of benthic crustaceans in Lake Mývatn, Iceland, is dynamic, with different taxa showing different patterns of variation through time. Here, we analyze the dynamics of eight crustaceans collected during the summer from a central station in Mývatn over 29 years, 1995–2023. We investigated the hypothesis that fluctuations in the dominant benthic tube-forming midge, Tanytarsus gracilentus , drives fluctuations in ben...

In nitrogen-limited lakes, cyanobacterial nitrogen (N) fixation rates can be high. However, the effect of cyanobacterial N fixation on ecosystem N availability depends, in part, on the retention of fixed N. Here, we explore patterns of benthic and pelagic N fixation and fixed N retention in Lake Mývatn, Iceland. Our N budget, updated from previous assessments, showed that the annual rate of lake-scale N fixation needed to acco...

While climate warming is widely predicted to reduce body size of ectotherms, evidence for this trend is mixed. Body size depends not only on temperature but also on other factors, such as food quality and intraspecific competition. Because temperature trends or other long‐term environmental factors may affect population size and food sources, attributing trends in average body size to temperature requires the separation of pot...