Palaeolimnological Studies of Human Impact on Aquatic Ecosystems

Palaeolimnology employs sedimentary archives from lakes, floodplains and estuaries to reconstruct past environmental and ecological conditions, offering a long-term perspective on how aquatic ecosystems respond to natural and anthropogenic stressors. By analysing biological remains (diatoms, cladocerans), geochemical proxies (stable isotopes, organic carbon, nutrient concentrations) and sedimentological features (lamination, grain size), researchers establish pre-impact baselines, detect regime shifts and quantify trajectories of degradation and recovery. Such reconstructions have revealed, for example, the role of post-industrial nutrient loading in driving eutrophication, the influence of catchment land-use change on sedimentation rates, and the effects of flow regulation and river impoundment on wetland food webs. Integrative approaches that combine palaeolimnological records with modern monitoring and numerical modelling enable practitioners to anticipate tipping points, inform restoration targets and guide water- and ecosystem-management policies at regional to global scales.

Research from Nature Portfolio

Numerical modelling of a mid-Holocene sea-level highstand in a major coastal plain estuary demonstrated how modest sea-level rises can generate extensive low-energy backwater environments, sequestering fine sediments over tens of kilometres and altering salinity distributions. A related study revealed that the geomorphic and depositional response of large catchment rivers to sea-level highstands can defy conventional estuarine models, emphasising the need to reconsider palaeoclimate reconstructions based on sediment delivered to the offshore environment. In a separate investigation, the integration of palaeoecological data with modern food-web analyses in a regulated floodplain wetland uncovered a sequence of trophic-state shifts following flow regulation, sediment accumulation and macrophyte expansion, illustrating how anthropogenic flow alteration can reshape sediment dynamics and faunal interactions over the past two centuries.

Palaeolimnological Studies of Human Impact on Aquatic Ecosystems publication trend

The graph below shows the total number of articles in palaeolimnological studies of human impact on aquatic ecosystems across all publications each year (not limited to Nature Index journals).

Technical terms

Palaeolimnology: The study of past lake and wetland conditions through analysis of sedimentary deposits and their biological, chemical and physical indicators.

Diatoms: Unicellular algae with siliceous cell walls whose sedimentary assemblages reflect historical changes in water chemistry, nutrient status and habitat structure.

Isotopic proxy: A geochemical indicator based on stable isotope ratios (e.g. δ13C, δ15N, δ18O) preserved in sediments or biogenic remains, used to infer past productivity, nutrient sources and hydrological regimes.

Trophic state: The level of biological productivity in an aquatic system, determined by nutrient availability and manifested in community composition and geochemical signatures.

References

1. Modelling Holocene analogues of coastal plain estuaries reveals the magnitude of sea-level threat. Scientific Reports (2019).
2. Atypical responses of a large catchment river to the Holocene sea-level highstand: The Murray River, Australia. Scientific Reports (2020).
3. Integration of palaeo-and-modern food webs reveal slow changes in a river floodplain wetland ecosystem. Scientific Reports (2020).
4. Diatoms in a sediment core from a flood pulse wetland in Malaysia record strong responses to human impacts and hydro‐climate over the past 150 years. Geo Geography and Environment (2020).
5. Using lake sediments to assess the long-term impacts of anthropogenic activity in tropical river deltas. The Anthropocene Review (2023).
6. N and C Isotope Variations Along an Extreme Eutrophication and Salinity Gradient in the Coorong Lagoon, South Australia. Frontiers in Earth Science (2022).