Small Waters Research Articles

Monitoring seasonal variations of colored dissolved organic matter for the Saginaw River based on Landsat-8 data

Abstract Remote sensing is an effective tool for studying CDOM (colored dissolved organic matter) variations and its relevant environmental factors. Monitoring CDOM distribution and dynamics in small water is often limited by the coarse spatial resolution of traditional ocean color sensors. In this study, because of its high spatial resolution of 30 m, Landsat-8 data were used to assess seasonal variations of CDOM in the Saginaw River, by using an empirical statistic model. Pearson correlation analysis between CDOM variations and other environmental factors, such as temperature, discharge, and dissolved oxygen, shows that temperature was negatively correlated to CDOM variations and discharge played a positive role. We also calculated the monthly mean aCDOM(440) (the absorption coefficient of CDOM at 440 nm) for the Saginaw River between April and November from 2013 to 2016. This study demonstrates a good example for future applications in small waters: observing CDOM variations and other relevant environmental factors change by using Landsat remote sensing, so that we can know more about water quality and ecosystem health of small waters as well as the climate change impact on regional watersheds.

Factors influencing return-to-creel of hatchery catchable-sized Rainbow Trout stocked in Idaho lentic waters

In recent years, increases in hatchery rearing and transport costs coupled with stagnate or declining funding has often resulted in reduced numbers of hatchery fish stocked in public waters. This has intensified the need to better understand how to maximize return-to-creel rates of hatchery trout by identifying factors contributing to better post-stocking performance. From 2011 through 2014, we tagged 50,745 catchable-sized hatchery Rainbow Trout Oncorhynchus mykiss and stocked them into 54 different lentic waters in Idaho (mostly impoundments) across 226 individual stocking events. Angler tag returns (n = 5092) were used to generate water-specific estimates of angler return rates (i.e., the proportion of stocked fish caught by anglers) and average days-at-large of captured fish. We then modeled water-specific angler return rates and days-at-large against a suite of water- and stocking-specific characteristics to determine what factors most influenced both angler returns and fishery longevity. First-year angler return rates across all four study years averaged 23% and ranged from 0% to 76% for individual stocking events; the variation in angler returns was best explained by mean fish length at stocking, water size, rearing hatchery, and water elevation. Average days-at-large for angled fish in individual waters varied from a low of 10 d to a high of 297 d, and this variation was best explained by water size, stocking season, and the rearing hatchery. We found the highest angler returns for larger trout stocked into smaller waters at lower elevations. However, these smaller waters also had shorter fisheries, requiring more frequent stocking to prolong the fisheries through the entire angling season. When considering these findings, managers must also consider the balance between angler catch, effort, and satisfaction as they work towards maximizing the benefit to anglers from put-and-take fisheries.

Synergy between nutrients and warming enhances methane ebullition from experimental lakes

Lakes and ponds are important natural sources of the potent greenhouse gas methane (CH4), with small shallow waters identified as particular hotspots1,2. Ebullition (bubbles) of CH4 makes up a large proportion of total CH4 flux3,4. However, difficulty measuring such episodic events 5 makes prediction of how ebullition responds to nutrient enrichment and rising temperatures challenging. Here, the world’s longest running, mesocosm-based, shallow lake climate change experiment was used to investigate how the combination of warming and eutrophication (that is, nutrient enrichment) affects CH4 ebullition. Eutrophication without heating increased the relative contribution of ebullition from 51% to 75%. More strikingly the combination of nutrient enrichment and experimental warming treatments of +2–3 °C and +4–5 °C had a synergistic effect, increasing mean annual ebullition by at least 1900 mg CH4-C m−2 yr−1. In contrast, diffusive flux showed no response to eutrophication and only a small increase at higher temperatures (average 63 mg CH4–C m−2 yr−1). As shallow lakes are the most common lake type globally, abundant in highly climate sensitive regions 6 and most vulnerable to eutrophication, these results suggest their current and future contributions to atmospheric CH4 concentrations may be significantly underestimated. The combination of nutrient enrichment and warming has a synergistic effect on rates of methane ebullition from experimental lakes. This suggests methane emissions from shallow lakes may be significantly underestimated.

Bacterial processes and biogeochemical changes in the water body of kettle holes - mainly driven by autochthonous organic matter?

Kettle holes are small inland waters formed from glacially-created depressions often situated in agricultural landscapes. Due to their high perimeter-to-area ratio facilitating a high aquatic-terre ...

Potential disease transmission from wild geese and swans to livestock, poultry and humans: a review of the scientific literature from a One Health perspective

ABSTRACTThere are more herbivorous waterfowl (swans and geese) close to humans, livestock and poultry than ever before. This creates widespread conflict with agriculture and other human interests, but also debate about the role of swans and geese as potential vectors of disease of relevance for human and animal health. Using a One Health perspective, we provide the first comprehensive review of the scientific literature about the most relevant viral, bacterial, and unicellular pathogens occurring in wild geese and swans. Research thus far suggests that these birds may play a role in transmission of avian influenza virus, Salmonella, Campylobacter, and antibiotic resistance. On the other hand, at present there is no evidence that geese and swans play a role in transmission of Newcastle disease, duck plague, West Nile virus, Vibrio, Yersinia, Clostridium, Chlamydophila, and Borrelia. Finally, based on present knowledge it is not possible to say if geese and swans play a role in transmission of Escherichia coli, Pasteurella, Helicobacter, Brachyspira, Cryptosporidium, Giardia, and Microsporidia. This is largely due to changes in classification and taxonomy, rapid development of identification methods and lack of knowledge about host specificity. Previous research tends to overrate the role of geese and swans as disease vectors; we do not find any evidence that they are significant transmitters to humans or livestock of any of the pathogens considered in this review. Nevertheless, it is wise to keep poultry and livestock separated from small volume waters used by many wild waterfowl, but there is no need to discourage livestock grazing in nature reserves or pastures where geese and swans are present. Under some circumstances it is warranted to discourage swans and geese from using wastewater ponds, drinking water reservoirs, and public beaches. Intensified screening of swans and geese for AIV, West Nile virus and anatid herpesvirus is warranted.

The importance of small waterbodies for biodiversity and ecosystem services: implications for policy makers

Small waterbodies, including ponds and small lakes, low-order streams, ditches and springs, are the most numerous freshwater environments globally, are critical for freshwater biodiversity and are increasingly recognised for their role in ecosystem service delivery. Small waters often represent the best remaining examples of intact freshwater habitats and are the most likely to remain unpolluted, often being a refuge for species which have disappeared from larger, more damaged, waterbodies. Practically all water-related ecosystem services are initially mediated by small waters and some, such as carbon cycling, may be dominated by them. Small waters are exposed to all the threats affecting larger waters, and some experienced only by small waters. Despite this, small waters remain the least investigated part of the water environment and are largely excluded from water management planning. We identify the priorities for research to underpin better protection of small waters and recommend policy actions needed to better integrate small waters into the management of catchments and landscapes. The primary requirements are to identify reliable monitoring programmes for small waters, develop effective measures to protect the biodiversity and ecosystem services they provide and ensure that regulators take full account of this critical part of the water environment.

Effects of Rearing Density on Return to Creel of Hatchery Catchable Rainbow Trout Stocked in Idaho Lentic Waters

AbstractEvaluating rearing techniques that maximize angler returns to creel of hatchery trout is an essential tool in shaping hatchery management practices and maximizing the public use of hatchery products. The goal of this study was to determine the effects of raceway rearing density on return to creel of catchable-sized (mean TL ≈ 252 mm) hatchery Rainbow Trout Oncorhynchus mykiss. In 2011 and 2012, Idaho Department of Fish and Game reared catchable-sized trout targeting three maximum density indices (0.15, 0.25, and 0.30 lb·ft−3·in−1) at three different state fish hatcheries. Each hatchery stocked fish into the same 11 lakes and reservoirs to evaluate return-to-creel rates by rearing density. Although there was a trend of lower angler catch for fish reared at a higher raceway density, the relationship was not statistically significant. Instead, angler catch was significantly influenced by fish size at stocking and the surface area of the water being stocked, whereby larger fish and smaller waters had ...

The importance of landscape diversity for carbon fluxes at the landscape level: small‐scale heterogeneity matters

Landscapes can be viewed as spatially heterogeneous areas encompassing terrestrial and aquatic domains. To date, most landscape carbon (C) fluxes have been estimated by accounting for terrestrial ecosystems, while aquatic ecosystems have been largely neglected. However, a robust assessment of C fluxes on the landscape scale requires the estimation of fluxes within and between both landscape components. Here, we compiled data from the literature on C fluxes across the air–water interface from various landscape components. We simulated C emissions and uptake for five different scenarios which represent a gradient of increasing spatial heterogeneity within a temperate young moraine landscape: (I) a homogeneous landscape with only cropland and large lakes; (II) separation of the terrestrial domain into cropland and forest; (III) further separation into cropland, forest, and grassland; (IV) additional division of the aquatic area into large lakes and peatlands; and (V) further separation of the aquatic area into large lakes, peatlands, running waters, and small water bodies These simulations suggest that C fluxes at the landscape scale might depend on spatial heterogeneity and landscape diversity, among other factors. When we consider spatial heterogeneity and diversity alone, small inland waters appear to play a pivotal and previously underestimated role in landscape greenhouse gas emissions that may be regarded as C hot spots. Approaches focusing on the landscape scale will also enable improved projections of ecosystems’ responses to perturbations, e.g., due to global change and anthropogenic activities, and evaluations of the specific role individual landscape components play in regional C fluxes. WIREs Water 2016, 3:601–617. doi: 10.1002/wat2.1147This article is categorized under: Water and Life > Nature of Freshwater Ecosystems Science of Water > Water and Environmental Change Science of Water > Water Quality

Chemical composition of geographical types of the small river basin waters (Central Sikhote-Alin Mountains, Pacific Asia)

In the article, the results of field observations of the chemical composition of the small river basin waters obtained during warm periods in 2011–2012 are presented. Seven basic geographical types of water were investigated, namely, cyclonic rainfall, rainstorm, throughfall, subsurface soil flow, low water flow (specific discharges of waters do not exceed 2.5 L/s km2), low floods (peak specific discharges are from 2.5 to 16 L/s km2) and medium floods (peak specific discharges are from 16 to about 100 L/s km2). A result of the interaction between the rain water and landscape constituents is that all examined natural waters differ to the maximum extent in the anionic composition. A chemical type of stream waters is sufficiently stable; it is formed predominantly within the soil-ground cover and does not change with increase in flow rate.

Phytoplankton colonization patterns. Is species richness depending on distance among freshwaters and on their connectivity?

Phytoplankton assemblages in two Sicilian water bodies were compared to test the hypothesis that colonization events and the successful establishment of a new species in an aquatic ecosystem may depend on the number of water bodies in a given area and on their relative distance. The two ecosystems are both natural, shallow lakes and they are protected sites hosting a rich avifauna. Lake Biviere di Gela is located in an area with a high density of ponds, whereas Lake Pergusa is an isolated waterbody without other aquatic ecosystems in its surroundings. Both lakes had almost disappeared about 10 years ago because of the over-exploitation of their main inflows. They were therefore re-filled using water from other catchments and their phytoplankton has been sampled since their re-filling. The results show that Lake Pergusa has maintained a species-poor phytoplankton assemblage since its re-filling, whereas Lake Biviere di Gela has been showing progressively richer phytoplankton assemblages during time. The composition of samples collected in nearby located temporary ponds suggests that phytoplankton in this area belongs to a species-rich metacommunity which favored its re-establishment in the lake. Aquatic ecosystems conservation plans cannot thus neglect the role of small waters located in the catchments.

Spatial and temporal variability of zooplankton off New Caledonia (Southwestern Pacific) from acoustics and net measurements

AbstractSpatial and temporal distribution of zooplankton off New Caledonia in the eastern Coral Sea was studied during two multidisciplinary cruises in 2011, during the cool and the hot seasons. Acoustic measurements of zooplankton were made using a shipborne acoustic Doppler current profiler (S‐ADCP), a scientific echosounder and a Tracor acoustic profiling system (TAPS). Relative backscatter from ADCP was converted to biomass estimates using zooplankton weights from net‐samples collected during the cruises. Zooplankton biomass was estimated using four methods: weighing, digital imaging (ZooScan), ADCP and TAPS. Significant correlations were found between the different biomass estimators and between the backscatters of the ADCP and the echosounder. There was a consistent diel pattern in ADCP derived biomass and echosounder backscatter resulting from the diel vertical migration (DVM) of zooplankton. Higher DVM amplitudes were associated with higher abundance of small zooplankton and cold waters to the south of the study area, while lower DVM amplitudes in the north were associated with warmer waters and higher abundance of large organisms. Zooplankton was largely dominated by copepods (71–73%) among which calanoids prevailed (40–42%), with Paracalanus spp. as the dominant species (16–17%). Overall, zooplankton exhibited low abundance and biomass (mean night dry biomass of 4.7 ± 2.2 mg m3 during the cool season and 2.4 ± 0.4 mg m3 during the hot season) but high richness and diversity (Shannon index ∼4). Substantially enhanced biomass and abundance appeared to be episodically associated with mesoscale features contributing to shape a rather patchy zooplankton distribution.

Microplastics in freshwater ecosystems: what we know and what we need to know.

BackgroundWhile the use of plastic materials has generated huge societal benefits, the ‘plastic age’ comes with downsides: One issue of emerging concern is the accumulation of plastics in the aquatic environment. Here, so-called microplastics (MP), fragments smaller than 5 mm, are of special concern because they can be ingested throughout the food web more readily than larger particles. Focusing on freshwater MP, we briefly review the state of the science to identify gaps of knowledge and deduce research needs.State of the scienceEnvironmental scientists started investigating marine (micro)plastics in the early 2000s. Today, a wealth of studies demonstrates that MP have ubiquitously permeated the marine ecosystem, including the polar regions and the deep sea. MP ingestion has been documented for an increasing number of marine species. However, to date, only few studies investigate their biological effects.The majority of marine plastics are considered to originate from land-based sources, including surface waters. Although they may be important transport pathways of MP, data from freshwater ecosystems is scarce. So far, only few studies provide evidence for the presence of MP in rivers and lakes. Data on MP uptake by freshwater invertebrates and fish is very limited.Knowledge gapsWhile the research on marine MP is more advanced, there are immense gaps of knowledge regarding freshwater MP. Data on their abundance is fragmentary for large and absent for small surface waters. Likewise, relevant sources and the environmental fate remain to be investigated. Data on the biological effects of MP in freshwater species is completely lacking. The accumulation of other freshwater contaminants on MP is of special interest because ingestion might increase the chemical exposure. Again, data is unavailable on this important issue.ConclusionsMP represent freshwater contaminants of emerging concern. However, to assess the environmental risk associated with MP, comprehensive data on their abundance, fate, sources, and biological effects in freshwater ecosystems are needed. Establishing such data critically depends on a collaborative effort by environmental scientists from diverse disciplines (chemistry, hydrology, ecotoxicology, etc.) and, unsurprisingly, on the allocation of sufficient public funding.

Phytoplankton Biomass and Composition in a River-Dominated Estuary During Two Summers of Contrasting River Discharge

Estuaries located in the northern Gulf of Mexico are expected to experience reduced river discharge due to increasing demand for freshwater and predicted periods of declining precipitation. Changes in freshwater and nutrient input might impact estuarine higher trophic level productivity through changes in phytoplankton quantity and quality. Phytoplankton biomass and composition were examined in Apalachicola Bay, Florida during two summers of contrasting river discharge. The 20 μm diatoms were an increasingly (20 to 70 %) larger component of phytoplankton biomass. Lower summer river discharges that lead to an areal contraction of lower (5–25 psu) salinity waters composed of higher phytoplankton biomass dominated by small ( 25 psu) salinity waters composed of relatively lower phytoplankton biomass and a higher percent contribution by >20 μm diatoms. A reduction in summer river discharge that leads to such a change in quantity and quality of estuarine phytoplankton available will result in a reduction in estuarine zooplankton productivity and possibly the productivity of higher trophic levels.

Aggregated indices for trends in eutrophication of different types of fresh water in the Netherlands

As in many European countries, eutrophication of surface waters is a key problem in the Netherlands, caused by high concentrations of nitrogen (N) and phosphorus (P). For implementation of the EU Water Framework Directive (WFD) in the Netherlands, surface water types have been identified and for each water type environmental quality standard concentrations (EQS) were determined for both nutrients. With these standards, a new method was developed to quantify trends in water quality with respect to eutrophication on a national scale for the period 1990–2010. Firstly, monitoring data were aggregated to seven classes of surface water. Next, for each water class and each nutrient, a Nutrient Index was developed to express the degree of exceedance of EQS (distance-to-target method). The Nutrient Index for N shows a minor exceedance of EQS as well as an improvement in all water types; for P, the index shows a major exceedance in small stagnant waters throughout the 1990–2010 period, whereas in major rivers and lakes levels were close to EQS. Thirdly, the indices for seven surface water classes were aggregated to one index for each nutrient, and finally to a national Eutrophication Index combining N and P. This Eutrophication Index integrates all monitoring data and shows an improvement in the period 1990–2003 and stabilization since 2004.

Development of a Small Aquatic Cutting Machine

To solve the aquatic cutting problems in small waters, an aquatic cutting device which can be installed on existing small vessels was developed. The device is simple and practical. Its cutting depth is adjustable and it can be quickly disassembled or installed. After analysis of forces on foundation and simulation in software ADAMS, it shows that the device meets the design requirements.

Estimating degradation rates in outdoor stagnant water by inverse modelling with TOXSWA: a case study with prosulfocarb

The regulatory risk assessment of pesticides requires the assessment of exposure of aquatic ecosystems in small surface waters adjacent to agricultural fields. This exposure is predicted using simulation models, for which an important input parameter is the degradation rate in water. In regulatory dossiers, the decline rate in water from outdoor mesocosms is often available, but this rate encompasses more processes than degradation. Therefore, a procedure was designed for estimating the degradation rate in water that was suitable for mesocosm studies with limited datasets, e.g. datasets lacking site-specific sorption coefficients and relevant sediment properties. The procedure, based upon inverse modelling with TOXSWA, has been tested on a dataset for prosulfocarb in stagnant ditches. A degradation half-life in the ditch water of 2.9 days (20 °C) was found. This short half-life was to a significant extent accounted for by biodegradation rather than hydrolysis or photolysis. This half-life was considerably shorter than the half-life in the water layer of two laboratory water-sediment system experiments. The estimation procedure resulted in a unique half-life for the degradation rate in water. Such outdoor mesocosm studies seem to be better suited to assessing the degradation rate in water in ditches than the conventional water-sediment studies.

Design and performance of a filtration–adsorption pool train and drawing water system for small urban recreational water pollution control

A filtration–adsorption pool train (FAPT) and drawing water (DW) system was developed to control the small urban recreational water pollution at a senior hotel in Shanghai, China. The results from one year of operation indicated that the system had successfully achieved the water quality objectives: compared with the water quality before the treatment system worked, the average concentrations of SS, COD Mn, BOD 5, NH 3-N, TP and Chla were reduced by 79%, 39.5%, 45%, 36%, 44.3% and 70%, respectively, and DO and transparency were improved by 27% and 134%, respectively. The customers enjoyed a recreational, aesthetic and educational amenity along the ring pond. Therefore, it was conducted that the FAPT–DW system was an effective measure for small recreational waters, especially in urban areas with limited land resources.

Is Corophium Multisetosum Stock, 1952 an Exotic Invasive Species in Europe? Distribution, Habitat, and Recent Observations in the Netherlands

Abstract Corophium multisetosum Stock, 1952 has been found in several estuaries and water bodies in Europe ranging from fresh and brackish to salt water. The species appeared to be distributed over a wide geographic range from the Iberian Peninsula to the southern Baltic region and is recently found in the Mediterranean and Gulf of Mexico, showing remarkable differences in ecology between populations. The recorded observations of the species in the Netherlands, however, remained restricted to a few smaller waters, and were published in grey literature. Recently, the species has been observed in a variety of waters in the southwestern part of the Netherlands and appears to be relatively common. The current study gives an overview of the recordings of C. multisetosum within its geographic range and its habitat preferences. The recent observations on distribution and habitat preferences of C. multisetosum in the Netherlands are compared with the findings in other parts of Europe. Seeming discontinuities in recorded ecology of the species in the Netherlands and over Europe are discussed. C. multisetosum appears to be very flexible in its behaviour and appears to tolerate a broad range of environmental conditions. Local environmental conditions (e.g., salinity and substrate) and related communities (in the Netherlands particularly the presence of the seemingly competing species Corophium volutator (Pallas, 1766) and Chelicorophium curvispinum (G. O. Sars, 1895)) determine the presence of C. multisetosum and the local behaviour and abundance of the species in the system. As the species shows a typical distribution pattern with many recent recordings, its origin and possible dispersal routes are discussed.

Emerging global role of small lakes and ponds: little things mean a lot

Emerging global role of small lakes and ponds: little things mean a lot Until recently, small continental waters have been completely ignored in virtually all global processes and cycles. This has resulted from the neglect of these systems and processes by ecologists and the assumption that ecosystems with a small areal extent cannot play a major role in global processes. Recent inventories based on modern geographical and mathematical approaches have shown that continental waters occupy nearly twice as much area as was previously believed. Further, these inventories have shown that small lakes and ponds dominate the areal extent of continental waters, correcting a century- long misconception that large lakes are most important. The global importance of any ecosystem type in a process or cycle is the product of the areal extent and the intensity of the process in those ecosystems. Several analyses have shown the disproportionately great intensity of many processes in small aquatic ecosystems, indicating that they play an unexpectedly major role in global cycles. Assessments of the global carbon cycle underscore the need for aquatic scientists to view their work on a global scale in order to respond to the Earth's most pressing environmental problems.

EPILITHIC DIATOMS FROM RHEOCRENE SPRINGS IN THE EASTERN ALPS (VORARLBERG, AUSTRIA)

Benthic epilithic diatom assemblages were studied along with physico-chemical variables from 27 spring habitats situated in the western margin mountain area of the Eastern Alps (Vorarlberg, Austria) and were collected between the years 2003–2005. The sampling sites are situated in five of the seven aquatic ecoregions, as defined by the Austrian ecological quality assessments program of rivers. The sites occur over a wide altitudinal range (580 to 1800 m above sea level). The present study attempts to test the bioregional approach for the differentiation of rheocrene spring habitats, a spring type closely related to small running waters. Spring diatom assemblages primarily reflected the influence of the nutrient content, altitude, flow regime and mineral content but also are differentiated on a smaller scale by the main habitat peculiarities. The most frequent and abundant taxa were common elements of alpine lotic sites, the differentiation of assemblages appeared in the subdominant or even rare taxa (e.g. Gomphonema occultum, Encyonopsis microcephala, Delicata delicatula). Altogether the diatom composition comprised 197 taxa with >50% typical from lotic environments and 9% crenophilous taxa (having a strong affinity to springs, e.g. Delicata delicatula, Diatoma mesodori). Nitrate concentration and pH showed the greatest effect on the species composition but site-to-site characteristics also depended on the availability of substrates (e.g. wet rocks) and/or irregular discharge. Moisture indicator values, taking into consideration the distribution of taxa linked to water level fluctuations, were given for 57% of the species found (112 taxa). Fifteen percent of these taxa were generally occurring on wet and moist or temporarily dry places (springs—Navicula stromii, Rhopalodia gibba, moss habitats—Encyonopsis falaisensis, Pinnularia borealis) and another 4% nearly exclusively outside water bodies (e.g. Diadesmis gallica var. perpusilld). The latter group indicated either non-permanent sites or springs emerging from unstable ground. The number of threatened taxa (25%) according to the German Red List for diatoms was less than what was expected when compared to former studies based on Southern Alpine springs (50%) or Central Germany (31%). This reduction in red list species went along with higher nitrate concentrations, irregular discharge and minor human impact, since only 50% of the sites were still undisturbed.