Enhanced Sediment Denitrification for Nitrogen Removal by Manipulating Water Level in the Lakeshore Zone

Denitrification of sediments is an important way to remove reactive nitrogen in lakeshore zones. In this work, we analyzed sediment denitrification patterns across the shore zone of Lake Taihu and explored their underlying mechanisms using flooding simulation experiments. The results showed that denitrification mainly occurred in the upper sediment layer (0–10 cm) and the denitrification rate was highest at the land–water interface (6.2 mg N/m2h), where there was a frequent rise and fall in the water level. Denitrification was weaker in the lakebed sediments (4.6 mg N/m2h), which were inundated long-term, and in the sediments of the near-shore zone (2.3 mg N/m2h), which were dried out for extended periods. Flooding simulation experiments further indicated a strong positive relationship between sediment denitrification rate and flooding frequency. When the flooding occurred once every 3, 6, 9, 12, or 15 days, the denitrification rate reached 7.6, 5.7, 2.8, 0.9, and 0.6 mg N/m2h, respectively. Frequent flooding caused alternating anoxic and aerobic conditions in sediments, accelerating nitrogen substrate supply and promoting the growth and activity of denitrifying bacteria. Based on these findings, we propose a possible strategy for enhancing sediment denitrification by manipulating the water level, which can help guide nitrogen removal in lakeshore zones.

Land Use and Land Cover Pattern as a Measure of Tourism Impact on a Lakeshore Zone

Lakes provide different ecosystem services, including those related to tourism and recreation. Sustainable development principles should be respected in lake tourism planning. The aim of this study was to assess the impact of tourism on the lakeshore zone in a typical post-glacial Lakeland in Northern Poland (Central Europe). An explanatory analysis of the distribution of individual spatial factor values was performed using the SHapley Additive exPlanations algorithm (SHAP). In a first step, the aim was to select a Machine Learning model for modelling based on Shapley values. The greater or lesser influence of a given factor on the tourism function was measured for individual lakes. The final results of ensemble modelling and SHAP were obtained by averaging the results of five random repetitions of the execution of these models. The impact of tourism on the lakeshore zone can be much more accurately determined using an indirect method, by analysing the tourism and recreational infrastructure constantly present there. The values of the indices proposed in the study provide indirect information on the number of tourists using the tourist and recreational facilities and are a measure of the impact of tourism on the lakeshore zone. The developed methodology can be applied to the majority of post-glacial lakes in Europe and other regions of the world in order to monitor the threats resulting from shore zone exploitation. Such studies can be an appropriate tool for management and planning by the relevant authorities.

Coupling of Dual Channel Waveform ALS and Sonar for Investigation of Lake Bottoms and Shore Zones

In this work, we proposed to include remote sensing techniques as a part of the methodology for natural lake bottom mapping, with a focus on the littoral zone. Due to the inaccessibility of this zone caused by dense vegetation, measurements of the lake bottom and the coastline are also difficult to perform using traditional methods. The authors of this paper present, discuss and verify the applicability of remote sensing active sensors as a tool for measurements in the shore zone of a lake. The single-beam Lowrance HDS-7 ComboGPS echosounder with an 83/200 kHz transducer and a two-beam LiDAR RIEGL VQ-1560i-DW scanner have been used for reservoir bottom measurements of two neighboring lakes, which differ in terms of water transparency. The research has found a strong correlation between both sonar and LiDAR for mapping the bottom depth in a range up to 1.6 m, and allowed LiDAR mapping of approximately 20% of the highly transparent lake, but it has not been found to be useful in water with low transparency. In the light of the conducted research, both devices, sonar and LiDAR, have potential for complementary use by fusing both methods: the sonar for mapping of the sublittoral and the pelagic zone, and the LiDAR for mapping of the littoral zone, overcoming limitation related to vegetation in the lake shore zone.

Integration of a Shoreline Response Program (SRP) and SCAT

ABSTRACT The Shoreline Response Program (SRP) is an adjustment within an Incident Management System (IMS) intended to improve current practices. An SRP builds on the recognized strengths of an IMS-based organization and of a SCAT program that utilizes an integrated and focused approach to streamline and better coordinate the decision and planning processes and the operational implementation activities. An SRP is an extension of the traditional SCAT program but with a broader focuses on strategic and tactical planning to minimize the short- and long-term impacts of oil on shorelines, the efforts and costs involved in a shoreline response, and the volumes of waste that would be generated. The inclusion of an SRP concept in drills, exercises and preparedness training can directly improve the ability to respond quickly and effectively during the initial response phase. Not implementing an SRP at the very outset of a spill response, when typically the best opportunities exist for the removal of bulk oil, can have significant long-term consequences. Shifting an emphasis on management and physical resources from, often only partially successful, on-water activities to onshore shoreline activities when oil can be picked up more rapidly and effectively can significantly reduce i) the footprint of the response, ii) the duration and scale of the shoreline operation, iii) the exposure of shore zone resources to the oil, and so accelerate environmental recovery, and iv) waste generation.

Near-shore distribution of alien Ponto-Caspian amphipods in a European dam reservoir in relation to substratum type and occurrence of macroinvertebrate taxa

Knowledge of habitat requirements and interspecific interactions of invasive species helps predict their impact and spread. We determined the relationships within the invasive freshwater Ponto-Caspian amphipod assemblage, and their associations with macroinvertebrates in the near-shore zone of a central European lowland dam reservoir. We sampled five habitat types: bare sand at the water line, bare sand (0.2 m depth), bare sand (0.5 m depth), macrophyte-overgrown sand (1 m depth), stones (0.3 m depth) on four dates (October 2015–October 2016). Pontogammarus robustoides occurred in all habitats, Dikerogammarus villosus and Echinogammarus ischnus were limited to the stony bottom. Amphipod densities were positively associated with one another except Dikerogammarus juveniles, negatively correlated with adults. The occurrence of D. villosus, juvenile Dikerogammarus and E. ischnus was positively related to the presence of the shelter-forming bivalve Dreissena polymorpha. Pontogammarus robustoides was positively associated with sphaeriid clams and gastropods (shelters), as well as oligochaetes and chironomids (potential prey items). Dikerogammarus villosus and E. ischnus were positively related to chironomids and oligochaetes, respectively. Coexistence of various alien amphipods in the studied area, indicated by prevailing positive relationships in their assemblage, may be enabled by the abundance of shelters and rich food sources allowing habitat partitioning.

The Dredging Impact on the Lake Manzherok (Republic of Altay) Hydro/biological and Sanitary/micro/biological Characteristics

The article assesses ecological status of the Lake Manzherok (Republic of Altay Mayminsk Rayon) by its hydro/biological and sanitary/micro/biological characteristics after completion of dredging works. To estimate the bio/ceonosis dynamics we used the archive data of 2007–2015 and references. The aquatic communities demonstrated low indicators of development, phytoplankton – 26 taxons, abundance did not exceed 1.3·103 thousand cells/m3, biomass did not exceed 64.0·10-3 mg/m3. In water we found the sapropel vegetative pigments with the chlorophyll a of 237 mg/m3. We identified 16 species of zooplankton with 3. 5 –18.2 t housa nd pieces/m3 abu nda nce w it h 23.4 –97. 3 mg/m3 biomass. In comparison with 2015 the filtering zooplankton organisms’ abundance and biomass were 10–15 times lower. In contrast with 14–15 species in previous years we identified 5 species of macrophytes. The benthos abundance was not more than 1.48 thousand pieces/m2, the biomass did not exceed 1.56 g/m2, that is lower than in 2007. Such low indicators of the aquatic communities’ development with high concentration of organic matter argue the temporal state of anthropogenic metabolic regress. The Lake Manzherok water quality by its sanitary/micro/biological characteristics did not agree with the requirements to recreational water bodies. The whole content of coliform bacteria in the off-shore zone 25 times exceeded the norm, while the content of thermo/tolerant coliform bacteria in the center of the lake and in the macrophytes tangle 2.3 times exceeded the norm.

ХРОНОЛОГИЧЕСКИЕ РАМКИ АРХЕОЛОГИЧЕСКИХ КОМПЛЕКСОВ МНОГОСЛОЙНОГО ПАМЯТНИКА СЕРТЕЯ II (ПО ДАННЫМ РАДИОУГЛЕРОДНОГО ДАТИРОВАНИЯ)

Dr. Ganna Zaitseva participated a lot in researches conducted within the North-Western archaeological expedition of the State Hermitage Museum and elaborating the chronological timeframes for Neolithic in this region. Multidisci- plinary investigations of the last five years changed a lot historical schemes and environmental reconstructions made for Serteya II site, located in Smolensk region. The Serteya II site is a multilayer complex used by hunter–fisher–gath- erer communities in the 9th-8th mill. BC, and from the end of the 7th till the end of the 3rd mill. BC. Archaeological structures and horizons were developed in the palaeolake shore zone within changing water regimes and changes in the environmental conditions. Based on the most convergent dendrochronological sequences, two floating chronolo- gies were compiled, for pine wood 53 years old and larch wood 54 years old. Finally five OSL dates have been obtained, but the acquired age of geological ones significantly exceeded expectations. Three dates indicate the Neolithic period (contrary to expected XVII century), and a chronological inversion of OSL dates can be seen. Surprisingly spectrom- etry measurements of gytia sediments, despite of significant amount of organic matter allow as to calculate the dose rate and then to date one piece of Neolithic pottery. The obtained age perfectly corresponded to present state of knowledge.