| 1. |
- Almeida, Rafael M., et al.
(författare)
-
Phosphorus transport by the largest Amazon tributary (Madeira River, Brazil) and its sensitivity to precipitation and damming
- 2015
-
Ingår i: Inland Waters. - 2044-2041 .- 2044-205X. ; 5:3, s. 275-282
-
Tidskriftsartikel (refereegranskat)abstract
- Originating in the Bolivian and Peruvian Andes, the Madeira River is the largest tributary of the Amazon River in terms of discharge. Andean rivers transport large quantities of nutrient-rich suspended sediments and are the main source of phosphorus (P) to the Amazon basin. Here, we show the seasonal variability in concentrations and loads of different P forms (total, particulate, dissolved, and soluble reactive P) in the Madeira River through 8 field campaigns between 2009 and 2011. At our sampling reach in Porto Velho, Brazil, the Madeira River transports similar to 177-247 Gg yr(-1) of P, mostly linked to particles (similar to 85%). Concentrations and loads of all P forms have a maximum at rising waters and a minimum at low waters. Total P concentrations were substantially higher at a given discharge at rising water than at a similar discharge at falling water. The peak of P concentrations matched the peak of rainfall in the upper basin, suggesting an influence of precipitation-driven erosion. Projected precipitation increase in the eastern slopes of the Andes could enhance sediment yield and hence the P transport in the Madeira River. Because most of the P is particulate, however, we hypothesize that the planned proliferation of hydropower dams in the Madeira basin has the potential to reduce P loads substantially, possibly counteracting any precipitation-related increases. In the long term, this could be detrimental to highly productive downstream floodplain forests that are seasonally fertilized with P-rich deposits.
|
|
| 2. |
|
|
| 3. |
- Brentrup, Jennifer A., et al.
(författare)
-
The potential of high-frequency profiling to assess vertical and seasonal patterns of phytoplankton dynamics in lakes : an extension of the Plankton Ecology Group (PEG) model
- 2016
-
Ingår i: Inland Waters. - 2044-2041 .- 2044-205X. ; 6:4, s. 565-580
-
Tidskriftsartikel (refereegranskat)abstract
- The use of high-frequency sensors on profiling buoys to investigate physical, chemical, and biological processes in lakes is increasing rapidly. Profiling buoys with automated winches and sensors that collect high-frequency chlorophyll fluorescence (ChlF) profiles in 11 lakes in the Global Lake Ecological Observatory Network (GLEON) allowed the study of the vertical and temporal distribution of ChlF, including the formation of subsurface chlorophyll maxima (SSCM). The effectiveness of 3 methods for sampling phytoplankton distributions in lakes, including (1) manual profiles, (2) single-depth buoys, and (3) profiling buoys were assessed. High-frequency ChlF surface data and profiles were compared to predictions from the Plankton Ecology Group (PEG) model. The depth-integrated ChlF dynamics measured by the profiling buoy data revealed a greater complexity that neither conventional sampling nor the generalized PEG model captured. Conventional sampling techniques would have missed SSCM in 7 of 11 study lakes. Although surface-only ChlF data underestimated average water column ChlF, at times by nearly 2-fold in 4 of the lakes, overall there was a remarkable similarity between surface and mean water column data. Contrary to the PEG model's proposed negligible role for physical control of phytoplankton during the growing season, thermal structure and light availability were closely associated with ChlF seasonal depth distribution. Thus, an extension of the PEG model is proposed, with a new conceptual framework that explicitly includes physical metrics to better predict SSCM formation in lakes and highlight when profiling buoys are especially informative.
|
|
| 4. |
- Côté, Marianne, et al.
(författare)
-
Towards modeling data-poor lakes at the regional scale using parameters from data-rich lakes and relationships to lake characteristics
- 2023
-
Ingår i: Inland Waters. - : Taylor & Francis. - 2044-2041 .- 2044-205X. ; 13:3, s. 388-401
-
Tidskriftsartikel (refereegranskat)abstract
- Lakes pivotal for recreation and economically relevant activities are often remote and not well studied, which hinders the application of predictive lake models for their management. Here, we provide an approach to simulate—by means of the process-oriented model MyLake—water temperature, ice cover duration, dissolved oxygen, and light attenuation in 198 data-poor lakes based on parameters obtained for a subgroup of 12 data-rich lakes and morphometric data. Specifically, the model is first calibrated using a genetic algorithm on well-studied lakes. Simple relationships between the fitted parameters and lake-catchment morphometric properties are then derived, and the results of simulations using fitted and derived parameters are compared. The loss in goodness-of-fit, expressed as root mean square error (RMSE) incurred by using estimated rather than calibrated parameters, is 0.17 °C for water temperature and 0.82 mg L−1 for dissolved oxygen. These general relationships are then used to provide the model parameters for 198 data-poor lakes distributed throughout Sweden and to model these lakes. Overall, this proof of concept allows simulating lakes selected based on their relevance for lake management rather than based on the availability of extensive field datasets.
|
|
| 5. |
- De Leeuw, Joep
(författare)
-
The importance of flooded terrestrial habitats for larval fish in a semi-natural large floodplain (Volga, Russian Federation)
- 2016
-
Ingår i: Inland Waters. - 2044-2041 .- 2044-205X. ; 6, s. 105-110
-
Tidskriftsartikel (refereegranskat)abstract
- We assessed the importance of flooded terrestrial habitats for fish larvae in a semi-natural large floodplain (Volga, Russian Federation) by comparing abundances at the shoreline of permanent waterbodies with flooded terrestrial habitats. We found that overall larval abundance at the shoreline of permanent waterbodies was 6 to 10 times higher than in flooded terrestrial habitats and was highly consistent over the sampled waterbodies during the 2 year study. The potential mechanisms underlying these results are that shoreline habitats receive an influx of food with retreating warmer water from flooded terrestrial habitats, whereas the risk of hypoxia and stranding is lower at the shoreline than in flooded terrestrial habitats. Furthermore, the risk of predation is also lower at the shoreline compared to the open water habitats. Thus, we hypothesize that, rather than directly providing nursery habitat, the most important function of flooded terrestrial areas for the recruitment of fish in river floodplains is the production of food organisms that become available for larvae and juveniles with the retreating water.
|
|
| 6. |
- Denfeld, Blaize A., et al.
(författare)
-
Heterogeneous CO2 and CH4 patterns across space and time in a small boreal lake
- 2020
-
Ingår i: Inland Waters. - : Taylor & Francis. - 2044-2041 .- 2044-205X. ; 10:3, s. 348-359
-
Tidskriftsartikel (refereegranskat)abstract
- Small boreal lakes emit large amounts of carbon dioxide (CO2) and methane (CH4) to the atmosphere. Yet emissions of these greenhouse gases are variable in space and time, in part due to variable within-lake CO2 and CH4 concentrations. To determine the extent and the underlying drivers of this variation, we measured lake water CO2 and CH4 concentrations and estimated associated emissions using spatially discrete water samples collected every 2 weeks from a small boreal lake. On select dates, we also collected groundwater samples from the surrounding catchment. On average, groundwater draining a connected peat mire complex had significantly higher CO2 and CH4 concentrations compared to waters draining forest on mineral soils. However, within the lake, only CH4 concentrations nearshore from the mire complex were significantly elevated. We observed little spatial variability in surface water CO2; however, bottom water CO2 in the pelagic zone was significantly higher than bottom waters at nearshore locations. Overall, temperature, precipitation, and thermal stratification explained temporal patterns of CO2 concentration, whereas hydrology (discharge and precipitation) best predicted the variation in CH4 concentration. Consistent with these different controls, the highest CO2 emission was related to lake turnover at the end of August while the highest CH4 emission was associated with precipitation events at the end of June. These results suggest that annual carbon emissions from small boreal lakes are influenced by temporal variation in weather conditions that regulate thermal stratification and trigger hydrologic land-water connections that supply gases from catchment soils to the lake.
|
|
| 7. |
- Dessborn, Lisa, et al.
(författare)
-
Geese as vectors of nitrogen and phosphorus to freshwater systems
- 2016
-
Ingår i: INLAND WATERS. - 2044-2041 .- 2044-205X. ; 6:1, s. 111-122
-
Tidskriftsartikel (refereegranskat)abstract
- Many goose populations have increased dramatically over the past decades, which may influence inland waters used as roost sites. We reviewed the role of geese in the influx of nitrogen and phosphorus to freshwater systems. Several methods have been used to estimate guanotrophication impacts of geese. Water and sediment analysis have been conducted in areas of high and low geese presence; however, productive wetlands tend to attract more birds, and the causality is therefore ambiguous. Faecal addition experiments have attempted to estimate the impacts of droppings on water chemistry, sediments, algal growth, or invertebrate densities. The most common method of estimating goose guanotrophication is by extrapolation, usually based on multiplication of faecal production and its nutrient content. Based on such studies and those including information about daily migration patterns, we developed an approach to improve estimates of the nutrient contribution of geese. The relative role of geese in wetland eutrophication is also affected by the influx from alternative sources. The greatest guanotrophication impacts are likely found in areas with few alternative nutrient sources and with large goose flocks. Limited inflow and outflow of a freshwater system or a scarcity of wetland roosts may also increase problems at a local scale. Although several studies have looked at the impacts of geese on, for example, water chemistry or soil sediments, the effects are often smaller than expected, in part because no study to date has assessed the ecosystem response by including impacts on all levels, including water nutrient levels, nutrient sedimentation, chlorophyll content, and zooplankton response.
|
|
| 8. |
- Dessborn, Lisa, et al.
(författare)
-
Geese as vectors of nitrogen and phosphorus to freshwater systems
- 2016
-
Ingår i: Inland Waters. - : Freshwater Biological Association. - 2044-2041 .- 2044-205X. ; 6:1, s. 111-122
-
Tidskriftsartikel (refereegranskat)abstract
- Many goose populations have increased dramatically over the past decades, which may influence inland waters used as roost sites. We reviewed the role of geese in the influx of nitrogen and phosphorus to freshwater systems. Several methods have been used to estimate guanotrophication impacts of geese. Water and sediment analysis have been conducted in areas of high and low geese presence; however, productive wetlands tend to attract more birds, and the causality is therefore ambiguous. Faecal addition experiments have attempted to estimate the impacts of droppings on water chemistry, sediments, algal growth, or invertebrate densities. The most common method of estimating goose guanotrophication is by extrapolation, usually based on multiplication of faecal production and its nutrient content. Based on such studies and those including information about daily migration patterns, we developed an approach to improve estimates of the nutrient contribution of geese. The relative role of geese in wetland eutrophication is also affected by the influx from alternative sources. The greatest guanotrophication impacts are likely found in areas with few alternative nutrient sources and with large goose flocks. Limited inflow and outflow of a freshwater system or a scarcity of wetland roosts may also increase problems at a local scale. Although several studies have looked at the impacts of geese on, for example, water chemistry or soil sediments, the effects are often smaller than expected, in part because no study to date has assessed the ecosystem response by including impacts on all levels, including water nutrient levels, nutrient sedimentation, chlorophyll content, and zooplankton response.
|
|
| 9. |
- Downing, J. A., et al.
(författare)
-
Global abundance and size distribution of streams and rivers
- 2012
-
Ingår i: Inland Waters. - 2044-2041 .- 2044-205X. ; 2:4, s. 229-236
-
Tidskriftsartikel (refereegranskat)abstract
- To better integrate lotic ecosystems into global cycles and budgets, we provide approximations of the size-distribution and areal extent of streams and rivers. One approach we used was to employ stream network theory combined with data on stream width. We also used detailed stream networks on 2 continents to estimate the fraction of continental area occupied by streams worldwide and corrected remote sensing stream inventories for unresolved small streams. Our estimates of global fluvial area are 485 000 to 662 000 km2 and are +30–300% of published appraisals. Moderately sized rivers (orders 5–9) seem to comprise the greatest global area, with less area covered by low and high order streams, while global stream length, and therefore the riparian interface, is dominated by 1st order streams. Rivers and streams are likely to cover 0.30–0.56% of the land surface and make contributions to global processes and greenhouse gas emissions that may be +20–200% greater than those implied by previous estimates.
|
|
| 10. |
- Fehlinger, Lena, et al.
(författare)
-
The ecological role of permanent ponds in Europe : a review of dietary linkages to terrestrial ecosystems via emerging insects
- 2023
-
Ingår i: Inland Waters. - : Taylor & Francis. - 2044-2041 .- 2044-205X. ; 13:1, s. 30-46
-
Forskningsöversikt (refereegranskat)abstract
- Permanent ponds are valuable freshwater systems and biodiversity hotspots. They provide diverse ecosystem services (ESs), including water quality improvement and supply, food provisioning, and biodiversity support, despite significant pressure from multiple anthropogenic stressors and the impacts of ongoing global change. However, ponds are largely overlooked in management plans and legislation, and ecological research has focused on large freshwater ecosystems, such as rivers or lakes. Protection of ponds is often insufficient or indirectly provided via associated habitats such as wetlands. This situation is likely exacerbated by the lack of a full-scale understanding of the importance of ponds. In this review, we provide a detailed overview of permanent ponds across Europe, including their usages and the biodiversity they support. By discussing the concepts of pondscape and metacommunity theory, we highlight the importance of connectivity among and between ponds and identified fluxes of emerging insects as another ES of ponds. Those insects are rich in essential nutrients such as polyunsaturated fatty acids (PUFAs), delivered through them to the terrestrial environment; however, the extent and impact of this ES remains largely unexplored. Several potential stressors, especially related to ongoing global change, that influence pond diversity and integrity are discussed. We provide our insights on future pond management. Adaptive measures, taking into account the pond system per se within the pondscape, are the most promising to mitigate the loss of natural ponds and restore and conserve natural small waterbodies as refuges and diversity hotspots in increasingly urbanized landscapes.
|
|
