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Credit: MCR LTERReefs worldwide have abruptly and increasingly shifted from coral to seaweed dominated communities. Experiments at MCR LTER revealed that a large disturbance can cause a coral reef to flip to seaweeds indefinitely. Experiments and models showed that multiple stable states (e.g. corals or seaweeds) can continue to thrive under the same levels of… Read more »

Credit: Russell SchmittThe powerhouse mutualism between the coral animal and its symbiotic dinoflagellate algae is the backbone of coral reef ecosystems. Moorea Coral Reef LTER research has produced counter-intuitive results, specifically that flexibility with respect to symbionts does not automatically make corals resilient – a finding that has had profound implications for understanding the susceptibility… Read more »

Credit: NTL LTERLong term records show declining ice duration, lake warming, and increased variability in decadal lake level cycles. However, the magnitude of these physical changes, and their ecological consequences, differ substantially among lakes, including differences in warming rates, shifts in fish populations, and fluctuations in water clarity.

Credit: NTL LTERTerrestrial organic carbon (C) entering lakes can be stored, sent to the atmosphere as CO2, or passed downstream. Long term measurements of hydrology and C were used to understand and model the fate of terrestrial C in lakes. In Wisconsin’s 6,400 km2 Northern Highland Lake District (NHLD), the fraction of organic C converted… Read more »

Credit: NTL LTERRegime shifts are large, persistent, and often abrupt changes in ecosystem structure and function that may be difficult to reverse. Through long term whole ecosystem experiments and measurements, NTL LTER researchers have described regime shifts involving lake eutrophication and food web structure, and have used these case studies to develop conceptual and mechanistic… Read more »

Credit: NTL LTERLong term pre-invasion records provide an essential baseline for understanding invasive species effects, which can have profound consequences for ecosystems and society. In a key example, the spiny water flea invaded Lake Mendota, leading to massive declines in water quality and a loss in ecosystem services valued at $140 million.

Credit: Erika ZambelloAlthough bacteria play a central role in processes affecting lake water quality, the taxa participating in these activities are largely undescribed. To address this knowledge gap, NTL LTER researchers have generated the largest freshwater microbial genome collection to date. These studies reveal a paradoxical pattern of large differences in community structure over time… Read more »

Credit: Russ HopcroftThe coastal Gulf of Alaska water column is becoming progressively more stratified — the entire water column is warming, but more rapidly at the surface than near the seafloor, while near surface waters are becoming fresher. This is due to multiple factors including the air-sea heat flux, ocean heat flux convergences, the stabilizing… Read more »

Credit: Ana Aguilar-IslasReductions in primary producer average cell size and biomass followed the 2015-2016 warming, as did corresponding reductions at higher trophic levels. In addition, southern zooplankton species of smaller body size invaded the region and anomalous increases in gelatinous zooplankton population were observed. These changes, which could represent a window into the future of… Read more »

Credit: NGA LTERAlthough glacial input leads to high iron concentrations during summer and fall within the narrow Alaska Coastal Current, the ratio of iron to nitrate over the Northern Gulf of Alaska shelf in spring can be low enough to lead to nutritional stress in diatoms. This mismatch in essential nutrients likely affects phytoplankton community… Read more »