Aquatic Ecosystem Health and Management

An ecosystem-based approach requires an integration of knowledge systems and collaborative practices. The purpose of outreach, education, and knowledge mobilization is to (1) enhance the environmental literacy of people about the critical ecological and social functions of their ambient ecosystems; and (2) to enhance the production of information,...

Science is fundamental to sound policies, particularly when it comes to implementing an Ecosystem Approach. Science can and should inform nearly all facets of an Ecosystem Approach, yet challenges remain to realizing this goal.. To help identify and better understand these challenges we used a qualitative comparative case study approach to identify...

The Great Lakes and connecting waters encompass a vast and diverse ecosystem that presents scale challenges for management similar to those of the coastal ocean. Technological approaches to overcome the scale challenges have primarily been adapted from oceanographic applications and technologies, and from upscaling inland lake methods designed for...

Inland fisheries often receive little to no attention in global discussions about sustainable development. The consequences of overlooking inland fisheries in sustainability dialogues are increasingly problematic as fisheries stressors (e.g. overharvest, species invasion, climate change, habitat modification) intensify. Elevating the global profile...

of their riparian nations, providing, fisheries and aquaculture products, drinking water, microclimatic buffering, relatively cheap transport means, tourism, biodiversity, employment, and sources of energy (hydropower and oil). Economic growth comes with a cost in the form of pollution (municipal waste, industrial waste, sedimentation, agricultural...

Eutrophication continues in Lake Erie and low oxygen concentration remains a concern in the central basin of the lake. Summertime dissolved oxygen concentrations can be hypoxic (low dissolved oxygen) and anoxic (dissolved oxygen < 1 mg l-1) in the hypolimnion. We examined the spatial and temporal patterns of hypoxia in the central basin along a ~26...

Few lake-wide, seasonal primary production measurements have been made in Lake Erie. None more recent than 1997 have been reported in the literature. In 2019 we used 13 C uptake to measure production at 11 stations across the lake during three surveys in May, July, and September and at four of these stations during two additional surveys in April a...

Cyanobacterial bioactive metabolites (cyanotoxins/cyanopeptides) inhibit enzymes such as proteases, carboxypeptidases, and phosphatases that disrupt metabolic processes relevant to human and ecosystem health. From surface water samples collected in 2017 (n = 44), 2018 (n = 100), and 2019 (n = 171), we report concentrations of more than 20 biologica...

The early-life history stages of fish are sensitive to environmental change and therefore can indicate habitat quality as well as help predict recruitment of resident and transient fishes. In 2019, as part of the Lake Erie Cooperative Science and Monitoring Initiative, we conducted a lake-wide assessment of the ichthyoplankton community in U.S. nea...

Dreissenid mussels arrived at the Waverly Shoal located above the inflow of the Niagara River in 1989, initiating marked changes in the water and sediment chemistry, and benthic invertebrate community composition at an Ontario Ministry of the Environment, Conservation and Parks monitoring station. Here we examine change in the nearshore of eastern...

Larval fish growth and survival could be limited or reduced due to patchiness of zooplankton densities, even in productive aquatic systems. Recent declines in Lake Whitefish (Coregonus clupeaformis) populations prompted research to identify underlying mechanisms controlling survival at early life stages. In Lake Erie, the bottleneck window controll...

Little is known about external and internal loading and cycling of bioaccumulative methylmercury in Lake Erie, despite the lake having a world-renowned sport fishery. During the summer/early fall of 2018 to 2021, concentrations and fluxes of total mercury and methylmercury in the water column were examined near the Detroit and Maumee River discharg...

In the early 2000s, harmful algal blooms and hypoxia returned to Lake Erie following a period of ecosystem recovery from the late 1980s through the 1990s. This corresponds to a drastic increase in dissolved reactive phosphorus loads and flow-weighted mean concentrations in the major tributaries to the Western Lake Erie Basin. However, there is subs...

A mass balance model is presented that links the total phosphorus concentration in lakes to the water residence time, R w (lake volume divided by the annual water inflow) and the total phosphorus residence time, R p (average standing stock of lake total phosphorous divided by the external annual total phosphorus input). Following a change in the ex...

Over the past two decades, western Lake Erie has experienced recurring summer cyanobacterial blooms that pose severe negative impacts on human, animal, and ecological health. Previous research has identified a strong correlation between annual cyanobacterial bloom intensity and preceding spring (March-July) phosphorus loading from the Maumee river,...

The east basin of Lake Erie continues to suffer from blooms of filamentous green algae (primarily Cladophora). Potential management action through reduced phosphorus loadings have and continue to focus on the dissolved inorganic phosphorus pool but other potentially bioavailable phosphorus pools are not always considered. In this study, we describe...

This study reports directly measured nitrification rates in the water column of western Lake Erie, which is affected by annual cyanobacterial harmful algal blooms, and across all three Lake Erie basins. Over three field seasons, 15 NH 4 + stable isotope tracers were employed to quantify nitrification rates, and relative abundances of ammonia-oxidiz...

We measured Quagga Mussel grazing-induced changes in seston concentration in 20-L laboratory mesocosms containing lake water, during May-October, as part of a study to investigate the present role of mussel feeding and nutrient excretion in affecting phytoplankton composition. A variety of measuring methodologies including size-fractionated chlorop...

Numerical models are commonly used tools to simulate hydrodynamics and water quality of lakes. Model dimensionality (0D, 1D, 2D, or 3D) requires different simplification levels of physical-biogeochemical processes, computational power and calibration strategies and metrics against observations. To investigate these modelling considerations, the 1D...

To examine the potential impact of invasive dreissenid mussels on in situ populations of phytoplankton and nutrients in western Lake Erie, we combined mussel population estimates from a 2018 survey, results from mussel excretion, grazing, and in situ growth experiments, along with nutrient measurements on collected lake water. We calculated the pro...

Herein we provide experimental evidence for the effects invasive mussels (Dreissena) grazing can exert on a natural assemblage of plankton that included both hetero-and photo-trophic components in western Lake Erie. Five mussel feeding experiments were performed seasonally in 2018 (May, June, July August, October). Pre-and post-grazing samples were...

Invasive Quagga Mussels (Dreissena rostriformis bugensis) and Zebra Mussels (D. polymorpha) have been present in the Great Lakes for almost four decades and have caused substantial economic and environmental impacts. Factors that influence dreissenid mussel growth and population dynamics warrant more study, particularly for Quagga Mussels. We condu...

This article evaluates the role that different levels of control for combined sewer overflows have in addressing the recreational water quality objectives of the Toronto Inner Harbour of the Toronto and Region Remedial Action Plan. Three models are used to establish the predictive methodology: the Infoworks model for the combined sewer service area...

Many regions around the Great Lakes have been designated Areas of Concern as a result of consistent water quality problems from pollutants like phosphorus and Escherichia coli, which cause eutrophication, beach postings and Beneficial Use Impairments. While foreshore beach sand is a potential reservoir for E. coli, there is less understanding of wh...

We assessed fish community status for 16 nearshore areas in Lake Ontario and the upper St. Lawrence River, from 2006 to 2016, using complementary fish sampling gear types and protocols, boat electrofishing and trap nets, and the published aquatic ecosystem health indicators associated with them. Factors influencing Indices of Biotic Integrity score...

Bluffer's Park Beach in the Toronto and Region Area of Concern had a history of beach postings often exceeding 80% of the beach season since the 1980s. A study applied expanded E. coli surveillance and microbial source tracking techniques in 2005-2007 to identify fecal pollution sources contributing to beach postings. Expanded surveillance in the b...

The Toronto and Region Area of Concern (also known as Toronto Harbour) includes 42 km of Lake Ontario coastline and 6 watersheds. Over 4 million people reside within its boundaries which includes the City of Toronto (Ontario, Canada). We sampled eleven sites along the Lake Ontario coastline approximately monthly with 6 cruises from May to early Nov...

Instream barriers (e.g. dams, weirs and road crossings) fragment aquatic habitat and prevent the upstream movement of fish, impairing the ability of fishes to complete critical life stages, access critical habitat and for dispersal among local populations. Mitigation efforts have improved aquatic connectiv-ity to some degree, but it has been challe...

Toronto Harbour, adjacent to a large urban centre on Lake Ontario, receives inputs from storm sewers, combined sewer overflows, and urban runoff that lead to contrasting water quality over the waterfront. Toronto's Inner and Outer Harbours, mesotrophic and meso-oligotrophic, respectively, were investigated in 2008 to assess how water quality condit...

Coastal aquaculture is an important economic activity in India dominated majorly by shrimp culture, which involves a range of interconnected processes that are challenging to analyse and optimise without a systematic approach. System dynamics modelling is a useful tool for understanding and predicting the behavior of complex coastal aquaculture sys...

Size spectra are used to assess the status and functioning of marine and freshwater ecosystems worldwide. Their use is underpinned by theory linking the dynamics of trophic interactions to a power-law decline of abundance with body size in ecological communities. Recent papers on empirical size spectrum estimation have argued for Maximum Likelihood...

This study uses the local knowledge of artisanal fishers to assess ecosystem structure, functioning, and fishing impacts within a coastal lagoon in Uruguay. To this end, we used an Ecopath with Ecosim modelling approach based on fishers' knowledge and scientific data. The model considered 23 functional groups, while three fleets represented fishing...

Hypoxia (dissolved oxygen < 2 mg l-1) has long been a prevalent feature of the central basin of Lake Erie. Studies of the sublethal impacts of hypoxia on fishes have focused on individual species feeding rates, behavior and spatial distributions over short time periods, but the long-term effects on the fish community and its foodweb are poorly know...

Inland rift valley lake systems have been sustaining humanity for a long time. Only recently have commercial fisheries entered these systems and for Lake Malawi, this occurred in the mid-1970s upon successful experimental trawl fishing. Lake Malawi with the highest diversity of freshwater fishes in the world has had fisheries for centuries. Previou...

The Indian Sundarbans is considered one of the zones of highest vulnerability in the world in terms of climate change. About 4.43 million people living in the Indian Sundarbans face a lack of freshwater availability due to the erratic behaviour of monsoon rains, frequent cyclonic storms, intrusion of saline water, and other factors, all of which af...

As a result of natural and anthropogenic eutrophication, shallow lakes ultimately become wetlands. Several aquatic ecosystem values diminish, but some biotic communities may benefit. Lake Lahepera is a very shallow lake filled with sediments and overgrown with macrophytes. It is a former bay and an important spawning ground for fishes of Lake Peips...

Preface Globally, freshwaters are the most threatened ecosystems as the Anthropocene continues (Albert et al., 2021), with lakes bearing a large share of the impacts (Heino et al., 2021). While the rising impacts of climate change increasingly draw public attention, many other anthropogenic stressors (eutrophication; toxic and accumulating chemical...

A total of 25 algal blooms were observed during three separate surveys of the Bay of Quinte, Lake Ontario, conducted during August 2010, September 2010 and September 2011. Here we define algal blooms based on the direct measurement of phytoplankton biomass (>3 g m À3) and not proxy measures such as chlorophyll a. In this chronically eutrophic embay...

The Bay of Quinte, Hamilton Harbour and Toronto Harbour are all coastal regions of Lake Ontario that have experienced eutrophication and all have been designated as 'Areas of Concern' under the terms of the Great Lakes Water Quality Agreement. An assessment of the phytoplankton communities in relation to nutrient (P,N,Si) regimes was undertaken dur...

Eutrophication continues in Lake Erie and low oxygen concentration remains a concern in the central basin of the lake. Summertime dissolved oxygen concentrations can be hypoxic (low dissolved oxygen) and anoxic (dissolved oxygen < 1 mg l-1) in the hypolimnion. We examined the spatial and temporal patterns of hypoxia in the central basin along a ~26...

Indigenous knowledge systems, ways of knowing and being have long been ignored or erased in the science, policy, and management of ecosystems. Through the 2022 Ecosystem Approach Conference and Synthesis Workshop focusing on Indigenous relationships, we facilitated discussions which raised key concerns from Indigenous led environmental teams: fundi...

The Laurentian Great Lakes represent the largest freshwater basin on Earth, containing 21% of the world's surface fresh water by volume. Water level fluctuations are an ongoing concern and have received considerable attention in the area. We present a trend analysis of meteorological (air temperature, cloud cover, and wind speed) and hydrological (...

The focus of this study was the temporal and spatial variations of extreme significant wave heights and nearshore return-period wave heights in the South China Sea, based on the wave model and European Reanalysis-Interim data from 1979-2016. Measured buoy data were available from near Yongxing Island for comparison with the reanalysis data during t...

We developed and validated a Planktonic Index of Biotic Integrity for subtropical reservoirs to assess their ecosystem health. For this purpose, we analyzed the phytoplankton and zooplankton communities and determined reservoir trophic status in the Paranapanema River system (Southeast Brazil). Eleven dams were constructed in the main course of thi...

The relationship between zooplankton community structure and selected environmental conditions was investigated by simultaneous two-day consecutive sampling in the waters overlying coral and sand sites off Sibu Island and a seagrass site off Tinggi Island, Johor, Malaysia. A total of 129 taxa were identified, 60 non-copepod taxa and 69 copepod spec...

This study was conducted to assess the recruitment rate of coral spats and other invertebrates near to the coral reef ecosystem of Gulf of Mannar. The reef region examined was at Kurusadai Reef Complex (Gulf of Mannar) for this assessment. There were two sets of invertebrate settlement tripods deployed and exposed at a depth of 2m. Seventy two sett...

Different chemometric approaches were used to determine generic patterns in the temporal and spatial variations in the coastal water quality of the northern Yellow Sea off Yantai, China. Hierarchical cluster analysis grouped the 16 months into two periods (i.e. March-October and November-February), reflecting strong seasonality in the data, and gro...

Leizhou Peninsula is located in the Indo-Burma biodiversity hotspot. However, information about freshwater fish species in this peninsula is very scarce. Based on surveys and a literature review, a total of 100 freshwater fish species (92 native and eight non-native) within seven orders, 21 families and 70 genera, have been recorded in the Leizhou...

This overview compares algal blooms and pelagic fisheries of the Arabian Gulf with the Sea of Oman. The data consist of remotely sensed characteristics, directly sampled and modeled. Elucidated seasonal trends were based on 15-year seasonal means, as well as weekly time series of physical parameters. The environmental characteristics (namely photos...

Seasonal dynamics of microzooplankton and changes in environmental condition were analysed during a one-year field sampling campaign in the Sea of Oman at two different stations. Monsoon winds in this region cause distinct seasonality patterns with high primary productivity during the southwest monsoon in summer (June to October) and northeast mons...

Conductivity elevation produces osmotic stress to aquatic biota and then alters biological communities. The responses of stream fish to conductivity remain unclear and strategies for protection are poorly developed. We collected data of fish and conductivity from sixty-two sites of the Taizi River to evaluate the changes to the fish community and s...

When dealing with invasive fishes, permanent barriers may inhibit spread, but may not be feasible due to costs and logistical constraints. Alternatively, non-permanent barriers using electricity, light, sound, pressure, bubbles, and CO 2 are being developed and deployed in efforts to limit and prevent the spread of aquatic invasive species or to ac...

Analysis of beach profile data over the period 1992-2014 at 14 beaches on mainland Anguilla and the offshore cays of Prickly Pear and Sandy Island, showed an overall erosion trend with a mean erosion rate of À0.51 m yr À1. Eleven beaches showed erosion, while three beaches showed slight accretion. Over the period of measurement nine hurricanes pass...

Coastal wetlands in Qinhuangdao play a vital role in the regional ecological environment. The value of the ecosystem services of the coastal wetland was evaluated in terms of provision services, regulation services, culture services and supporting services by particular methods. Results indicated that coastal wetland area in Qinhuangdao was about 3...

Based on the geometry and surface in Daya Bay, we artificially divided the reclamation projects into three periods to analyze the influences and changes on hydrodynamic conditions as a result of the reclamation projects. Three periods of tidal current fields, tidal prisms, and water exchange capacity are simulated by the Finite-Volume, primitive eq...

The Intergovernmental Panel on Climate Change projects climate change effects based on several scenarios and highlights the potential regional changes of bioclimatic pressures up until 2100. Understanding the effects of climate change on the ecosystems is of utmost importance for nature conservation; biodiversity in riverine and coastal areas is th...

This paper presents an analysis of future research and development needs to assess the effectiveness of nature-based solutions for climate adaptation in watersheds at scale using hydrological models. Two main questions are addressed: to what extent are hydrological model approaches able to support decision making on nature-based solutions and adapt...

Deltas are areas where pressures (e.g. climate change, rapid urbanization, water related shocks and stressors) as well as opportunities (e.g. economic growth, delta-city metabolism, sustainable development) collide to an unprecedented extent. The deltas are considered to become the most vital and critical hotspots in the world for sustainable devel...

Multilateral Environmental Agreements are important international instruments for achieving sustainable development. Nevertheless, their implementation is often not easy and integration with scientific knowledge during implementation can be troublesome. The 1992 Convention on the Protection and Use of Transboundary Watercourses and International La...

Dams have often been constructed for hydropower, water storage and to support socioeconomic development, particularly in areas of water stress. In many places, the water stored in human-made reservoirs is essential to meet the development objectives of water supply, agriculture, industry, energy generation and other sectors. However, in the absence...

The health of soil-sediment-water ecosystems is under pressure from economic activities and a changing climate. This decreases health and hampers the service provision capacity of these ecosystems and thus impacts human well-being. Protecting and where feasible restoring of ecosystem health has currently become the key European environmental policy...

Since the soil quality Tool for Risk Identification, Assessment and Display (TRIAD) approach introduced the "three lines of evidence" accounting for chemical, toxicological and ecological stressors to explain adverse effects in biota, the assessment of contaminant risks in the environment has significantly evolved. The concept of chemical speciatio...

Roots Cees grew up in a small town in the southwest of the Netherlands. This part of the country is characterised by estuaries, as well as the dominant presence of dikes. They are the silent witnesses of centuries of securing land from floods and represent a culture of fearing, conquering, and embracing the sea. 'Sealand' is a world-famous delta re...

Cees was best described as an activist scientist, a connector bridging the divides in society and building bridges between people and planet. Working with youth, empowering the old, informing the policymakers, encouraging the politicians and inspiring his colleagues and friends. Cees' collaborative capacity made the world a better place. And, he ma...