Aquatic Ecosystem Model Research Articles

Dining in danger: Resolving adaptive fish behavior increases realism of modeled ecosystem dynamics.

Animals occupying higher trophic levels can have disproportionately large influence on ecosystem structure and functioning, owning to intricate behavioral responses to their environment, but the effects of behavioral adaptations on aquatic ecosystem dynamics are underrepresented, especially in model studies. Here, we explore how adaptive behavior of fish can affect the dynamics of aquatics ecosystems. We frame fish behavior in the context of the central trade-off between feeding and predation, calculating the optimal level of feeding determined by ambient food availability and predation risk. To explore whole-ecosystem consequences of fish behavior, we embed our behavioral model within the Water Ecosystems Tool (WET), a contemporary end-to-end aquatic ecosystem model. The principle of optimality provides a robust and mechanistic framework for representing animal behavior that is relevant for complex models, and can provide a stabilizing effect on model dynamics. The model predicts an emergent functional response similar to Holling type III, but with richer dynamics and a more rigorous theoretical foundation. We show how adaptive fish behavior works to stabilize food web dynamics compared to a control model with no optimal behavior, and how changing the strength of the underlying trade-off has profound effects on trophic control and food web structure. Furthermore, we demonstrate how including fish behavior allows for an overall more realistic response of the model system to environmental perturbation in the form of nutrient enhancement. We discuss the structuring effects of behavioral adaptations in real ecosystems, and how approaches like this one may benefit aquatic ecological modeling. Our study further highlights how a mechanistic approach based on concepts from theoretical ecology can be successfully implemented in complex operational models resulting in improved dynamics and descriptive power.

Using System‐Inspired Metrics to Improve Water Quality Prediction in Stratified Lakes

AbstractDespite the growing use of Aquatic Ecosystem Models for lake modeling, there is currently no widely applicable framework for their configuration, calibration, and evaluation. Calibration is generally based on direct data comparison of observed versus modeled state variables using standard statistical techniques, however, this approach may not give a complete picture of the model's ability to capture system‐scale behavior that is not easily perceivable in observations, but which may be important for resource management. The aim of this study is to compare the performance of “naïve” calibration and a “system‐inspired” calibration, an approach that augments the standard state‐based calibration with a range of system‐inspired metrics (e.g., thermocline depth, metalimnetic oxygen minima), to increase the coherence between the simulated and natural ecosystems. A coupled physical‐biogeochemical model was applied to a focal site to simulate two key state‐variables: water temperature and dissolved oxygen. The model was calibrated according to the new system‐inspired modeling convention, using formal calibration techniques. There was an improvement in the simulation using parameters optimized on the additional metrics, which helped to reduce uncertainty predicting aspects of the system relevant to reservoir management, such as the occurrence of the metalimnetic oxygen minima. Extending the use of system‐inspired metrics when calibrating models has the potential to improve model fidelity for capturing more complex ecosystem dynamics.

Are all copepods the same? Variation in copepod stoichiometry with taxonomy, ontogeny, latitude, and habitat

AbstractCopepods are the most abundant metazoans on Earth, driving cycles of key elements in aquatic systems, most prominently carbon (C), nitrogen (N), and phosphorus (P). One key factor determining nutrient cycling is copepod somatic stoichiometry, which can reflect ecological strategy. We conducted a systematic review that updates the seminal work of Båmstedt (1986) by summarizing the effects of latitude, habitat, life history stage, and taxonomy on C:N, C:P, and N:P ratios of field‐collected copepods. We found that differences among copepod families accounted for the greatest variation, with the Rhincalanidae and Diaptomidae being particularly C‐rich, while the Calanidae were more N‐ and P‐rich. Copepod C:N was higher in inland waters compared with animals from marine environments in both copepodites and adult females, matching the higher C content of seston in many inland freshwaters. For both copepodites and adult females, mid‐latitude animals had higher C:N and C:P than high‐latitude animals, which matched predictions based on the availability of nutrients or adaptation to cold environments. More data must be gathered to fill gaps in our knowledge of copepod stoichiometry, focusing particularly on younger life stages, non‐calanoids, low and high latitudes, the southern hemisphere, and estuarine and some inland water habitats, including large lakes. Such information will help better parameterize models of aquatic ecosystems and improve our understanding of how copepods influence consumer‐driven nutrient cycling and food web dynamics.

State of knowledge of aquatic ecosystem and fisheries of the Lake Edward System, East Africa

AbstractPoor and unreliable knowledge of the status of freshwater fisheries limits their inclusion in governance processes, thereby impeding effective management measures. This threatens the livelihoods of people, particularly in developing countries. Improved knowledge is required to draw the attention of policymakers and stimulate effective management measures to accelerate the sustainability of the freshwater fisheries. In line with this requirement, this paper provides the state of knowledge of the aquatic ecosystem and fisheries of the Lake Edward system, East Africa, focusing on lakes Edward, George and the Kazinga channel. The state of knowledge was accomplished by reviewing existing data and information on aspects of primary productivity and water quality, invertebrates, fish fauna, fish life history and ecology, and fisheries. The waterbodies have been monitored since the 1930s, albeit sporadically, providing data on all the above aspects but with substantial temporal gaps. Adequate and updated data and information exist on the water quality status of the water bodies, extant aquatic taxa (including fishes) and fish catches but with uncertainties in the latter. Data and information gaps exist on the abundance of biotic communities, fish life history, quantitative trophic ecology and fisheries management reference points. The aggregated data and information can directly support decisions for fisheries management. We recommend regular monitoring to fill the data and information gaps, more comprehensive stock assessments and the development of aquatic ecosystem models.

Calibration versus computation: Comparison between 1D and 3D phytoplankton simulations in western Lake Erie

Abstract 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 (vertical) Aquatic Ecosystem Dynamics – General Lake Model and the 3D Aquatic Ecosystem Model were applied to western Lake Erie in 2008 and 2011-14. The performance of the models was evaluated by comparing the simulations against observations of water temperature, total phosphorus, orthophosphate, nitrate, total chlorophyll-a and cyanobacteria at three stations located along a transect from the Maumee River mouth to mid-basin, as well as to the basin-averaged cyanobacteria index. The 3D model showed better skill in qualitatively reproducing seasonal and spatial variations of nutrients and phytoplankton and had lower average root-mean-square error, especially through the algal plume near the Maumee River mouth. However, the horizontally averaged 1D model performed better in qualitatively capturing the cyanobacteria bloom years, as this model was extensively calibrated to basin-average values. We conclude that models should be selected and calibrated to provide the required decision support information, rather than the highest resolution or lowest error metrics at discrete sites.

Timing matters: Sampling frequency for early-warning indicators across food web components in a virtual lake

Shallow lakes are known for sudden shifts between a desired clear and an undesired turbid state despite only incremental changes in the underlying drivers. Such sudden shifts are a major challenge for lake managers who can be confronted with abrupt losses of desired ecosystem services without easily observable warning signals. Predictive tools for the loss of ecosystem resilience are vital to respond with timely mitigation measures and avert a shift to the undesired state. Early-warning indicators (EWIs) have faithfully preceded critical transitions in minimal models but have proven more elusive in real-world data, suggesting a mismatch between measurement strategy and the detectability of EWIs. Here, we capitalize on data simulated using the aquatic ecosystem model PCLake+ which represents real systems more closely than reductionistic models and which allows the generation of critical transitions in response to gradual changes in phosphorus load. We tested the effect of different sampling intervals (daily to yearly) on the detection of three often-used EWIs across a range of food web and nutrient-related variables. Moreover, we included one integrated sampling interval (yearly average of daily measurements) to represent time-integrated measurements. EWIs generally performed better at shorter intervals (daily, weekly) but integrated measurements over the year also proved suitable to detect oncoming state shifts. We propose that lake managers should aim for high-frequency measurements of variables that can be easily and cheaply measured (e.g. oxygen, Secchi) or, alternatively, focus on integrated approaches using passive samplers or sedimented material.

The response of aquatic ecosystems to the interactive effects of stratospheric ozone depletion, UV radiation, and climate change

Variations in stratospheric ozone and changes in the aquatic environment by climate change and human activity are modifying the exposure of aquatic ecosystems to UV radiation. These shifts in exposure have consequences for the distributions of species, biogeochemical cycles, and services provided by aquatic ecosystems. This Quadrennial Assessment presents the latest knowledge on the multi-faceted interactions between the effects of UV irradiation and climate change, and other anthropogenic activities, and how these conditions are changing aquatic ecosystems. Climate change results in variations in the depth of mixing, the thickness of ice cover, the duration of ice-free conditions and inputs of dissolved organic matter, all of which can either increase or decrease exposure to UV radiation. Anthropogenic activities release oil, UV filters in sunscreens, and microplastics into the aquatic environment that are then modified by UV radiation, frequently amplifying adverse effects on aquatic organisms and their environments. The impacts of these changes in combination with factors such as warming and ocean acidification are considered for aquatic micro-organisms, macroalgae, plants, and animals (floating, swimming, and attached). Minimising the disruptive consequences of these effects on critical services provided by the world’s rivers, lakes and oceans (freshwater supply, recreation, transport, and food security) will not only require continued adherence to the Montreal Protocol but also a wider inclusion of solar UV radiation and its effects in studies and/or models of aquatic ecosystems under conditions of the future global climate.Graphical abstract

Dycdtools: an R Package for Assisting Calibration and Visualising Outputs of an Aquatic Ecosystem Model

The high complexity of aquatic ecosystem models (AEMs) necessitates a large number of parameters that need calibration, and visualisation of their multifaceted and multi-layered simulation results is necessary for effective communication. Here we present an R package "dycdtools" that contains calibration and post-processing tools for a widely applied aquatic ecosystem model (DYRESM-CAEDYM). The calibration assistant function within the package automatically tests a large number of combinations of parameter values and returns corresponding values for goodness-of-fit, allowing users to narrow parameter ranges or optimise parameter values. The post-processing functions enable users to visualise modelling outputs in four ways: as contours, profiles, time series, and scatterplots. The "dycdtools" package is the first open-source calibration and post-processing tool for DYRESM-CAEDYM, and can also be adjusted for other AEMs with a similar structure. This package is useful to reduce the calibration burden for users and to effectively communicate model results with a broader community.

Applying a hybrid model to support management of the endangered Topeka shiner in oxbow habitats

IntroductionHabitat restoration aims at reinstating abiotic and biotic habitat conditions to support long-term species persistence and viability. This management practice is commonly part of recovery plans developed for species listed as threatened or endangered under the Endangered Species Act. The endangered Topeka shiner (Notropis topeka) inhabits off-channel habitats, such as oxbow lakes which are increasingly the focus of restoration, but the exact abiotic conditions conducive to its persistence in this habitat are not fully understood. In this study, a hybrid model consisting of an individual-based model of the Topeka shiner and an aquatic ecosystem model representing the oxbow habitat was applied to identify optimal environmental conditions for the persistence of Topeka shiner populations.Materials and methodsEnvironmental conditions that correlated with Topeka shiner presence were gathered from published studies and included water temperature, turbidity, oxbow depth, light intensity (as a function of riparian vegetation presence), dissolved nitrogen, and dissolved phosphorus. Selected conditions were systematically varied in simulations and results were analyzed with a partial rank correlation method that quantifies the relative influence on model output from multiple factors.ResultsConducted simulations identified water temperature, depth, and dissolved inorganic nitrogen to be the most influential for Topeka shiner population biomass and additional simulations were conducted exploring the magnitudes and directions of effects of these three factors. Water temperature had the largest positive impact on population biomass followed by oxbow depth and nitrogen reduction.DiscussionWe recommend that the three identified factors be further explored in a combination of empirical and modeling approaches to advise management for the endangered Topeka shiner. This study demonstrated how ecological models could inform recovery plans by identifying factors that enhance species persistence. Ultimately, models should support management practices that result in long-term population viability of listed species and could facilitate their timely delisting.

Modeling framework for establishing the power law between length and weight of fishes and a meta-analysis for validation of LWRs for six commercially important marine fishes from the northwestern Bay of Bengal

Accurate and unbiased modeling of length-weight relationship (LWR) is essential for precise estimation of biomass from length-based abundance data for aquatic ecosystem modeling and developing resource management strategies for the sustainable utilization of aquatic living resources. The present study was conducted to develop the best modeling method for establishing the relationship between the length and weight of the fish, giving adequate priority to the variance distribution structure, which is often overlooked. Three modeling methods viz. (1) NLM: nonlinear model with additive homogeneous variance structure, (2) wNLM: weighted nonlinear model with additive heterogeneous power variance structure and (3) LM: log-transformed linear model with multiplicative heterogeneous variance structure in untransformed scale were evaluated for their performance in accurately estimating the model parameters and their confidence intervals. As variance in fish weight increases with the increase in fish size, usually, a multiplicative heterogeneous variance structure is assumed while explaining the relationship between length and weight, which was evidenced from the residual plot of NLM. As the data did not follow the additive homogenous variance assumption of NLM, the worst performance (highest AIC and BIC) was obtained when NLM was used. The variance distribution structure could be homogenized and normalized in three out of six fishes (i.e., Plicofollis layardi, Cynoglossus arel, Otolithes ruber) investigated in the study using LM, resulting in superior performance (lowest AIC and BIC) among the three models. For two out of three remaining species (i.e., Nemipterus japonicus and Parastromateus niger) for which the variance distribution cannot be normalized by log transformation (LM), the residuals could be homogenized and normalized by the wNLM which was evidenced by the lowest AIC and BIC for the model. Even for the species (i.e., Pampus argenteus), where the residuals could not be normalized by any of the models, better performance was obtained from wNLM. A meta-analysis was performed to validate the hitherto available information on the LWRs of these six species by regressing the regression parameters [log(a) vs. b] of the available LWRs and by computing the form factors. The erroneous LWRs were identified as doubtful reports by carefully scrutinizing the outliers obtained from Cook’s distance method and subsequently validating them by observing their dispersion from modeled prediction intervals (PI) and interquartile range (IQR) based outlier detection methods using the form factor analysis. The study presents the decision support framework for an appropriate modeling approach while dealing with certain assumptions such as variance normality and homoscedasticity. The study also describes a combined approach for the validation of derived LWRs by a comprehensive meta-analysis.

Effects of water diversion projects on water environment in Chaohu Lake

In recent years, more than 90% of lakes in China are facing different degrees of water pollution. As one of the five largest freshwater lakes in China, Chaohu Lake has a poor water environment where water blooms have frequently occurred. Water diversion is a main engineering method to promote the water exchange, shorten the water renewal cycle and improve environmental status, thus it is widely used in many lakes. Herein, this paper dynamically coupled PCLake aquatic ecosystem model and 3D finite volume FVCOM model to simulate the water environment response of Chaohu Lake under the non-diversion and different water diversion scheme conditions. The numerical results indicated that the optimal water diversion scheme is scheme A according to the water environment response results. When the water diversion volume is 3 × 109 m3 /year, the nutrient reduction efficiency and inhibition efficiency of water blooms in Chaohu Lake is the highest; the environment degree in Chaohu Lake is further significantly improved for the most time of a year with the increasing amount of water diversion. Although the water diversion project plays significantly positive roles in improving the environment of Chaohu Lake, it still cannot completely prevent the outbreak of serious water blooms.

SIGNS OF STABILITY OF AQUATIC ECOSYSTEMS IN MATHEMATICAL MODELS

To date, various data on water resources have been accumulated, but hydrobiological and hydrochemical indicators remain available to assess the current state of aquatic ecosystems, which can be the basis for assessing the environmental situation within the water body. Systematization of multiyear and diverse data on the lakes and rivers of the country, the use of mathematical tools for assessing and forecasting the state of the aquatic ecosystem is impossible without the use of information and communication technologies. Quality mathematical modeling of aquatic ecosystems and the development of information and analytical system for the study of aquatic ecosystems is an urgent task, including databases of various-quality data on the water body and its ecosystem, data management and processing tools, as well as a set of mathematical models for the functioning of the water body ecosystem. Research is based on information technology, statistical data processing, and mathematical modeling. Mathematical models are based on systems of differential equations, solutions are sought with the help of own computing programs and software suites (Maple, Matlab, Mathematics, etc.). When possible, modeling includes analytical studies of the properties of solutions, primarily this concerns stationary or spatially homogeneous solutions, as well as asymptotic properties of solutions. The lower trophic levels of the water body ecosystem are studied, as this determines the functioning of aquatic ecosystems. The species composition of phytoplankton is an indicator of the ecological state of the water body. Based on the quantitative characteristics of phytoplankton, the bioproductivity of the aquatic ecosystem is calculated. The physical and chemical characteristics of water allow drawing conclusions about the pollution of the water body and the composition of mineral nutrition for phytoplankton.

Close to reality? Micro-/mesocosm communities do not represent natural macroinvertebrate communities

BackgroundThe European environmental risk assessment of plant protection products considers aquatic model ecosystem studies (microcosms/mesocosms, M/M) as suitable higher tier approach to assess treatment-related effects and to derive regulatory acceptable concentrations (RAC). However, it is under debate to what extent these artificial test systems reflect the risks of pesticidal substances with potential harmful effects on natural macroinvertebrate communities, and whether the field communities are adequately protected by the results of the M/M studies. We therefore compared the composition, sensitivity and vulnerability of benthic macroinvertebrates established in control (untreated) groups of 47 selected M/M studies with natural stream communities at 26 reference field sites.ResultsSince 2013 the number of benthic macroinvertebrate taxa present in M/M studies has increased by 39% to a mean of 38 families per study. However, there is only an average of 4 families per study that comply with the recommendations provided by EFSA (EFSA J 11:3290, 2013), i.e.: (i) allowing statistical identification of treatment-related effects of at least 70% according to the minimum detectable difference (here criteria are slightly modified) and (ii) belonging to insects or crustaceans (potentially sensitive taxa for pesticidal substances). Applying the criterion of physiological sensitivity according to the SPEARpesticides concept, the number of families decreases from 4 to 2.3 per study.ConclusionsMost taxa established in recent M/M studies do not suitably represent natural freshwater communities. First, because their abundances are often not sufficient for statistical detection of treatment-related effects in order to determine an appropriate endpoint and subsequent RAC. Recommendations are given to improve the detectability of such effects and their reliability. Second, the taxa often do not represent especially sensitive or vulnerable taxa in natural communities in terms of their traits. The uncertainties linked to vulnerable taxa in M/M studies are especially high considering their representativity for field assemblages and the comparability of factors determining their recovery time. Thus considering recovery for deriving a RAC (i.e., ERO-RAC) is not recommended. In addition, this paper discusses further concerns regarding M/M studies in a broader regulatory context and recommends the development of alternative assessment tools and a shift towards a new paradigm.

Advances on water quality modeling in burned areas: A review

Wildfires are a recurring hazard in forested catchments representing a major threat to water security worldwide. Wildfires impacts on water quality have been thoroughly addressed by the scientific community through field studies, laboratory experiments, and, to a lesser extent, the use of hydrological models. Nonetheless, models are important tools to assess on-site and off-site wildfires impacts and provide the basis for post-fire land management decisions. This study aims to describe the current state of the art of post-fire model adaptation, understanding how wildfires impacts are simulated and the options taken by the modelers in selecting parameters. For this purpose, 42 publications on modeling wildfire impacts on the hydrologic cycle and water quality were retrieved from the SCOPUS database. Most studies simulated post-fire hydrological and erosion response in the first year after the fire, while few assessed nutrients changes and long-term impacts. In addition, most simulations ended at the watershed outlet without considering the fate of pollutants in downstream waterbodies. Ash transport was identified as a major research gap, given the difficulties of its incorporation in the current models’ structure and the high complexity in predicting the heterogeneous ash layer. Including such layer would improve models’ ability to simulate water quality in post-fire conditions, being ash a source of nutrients and contaminants. Model complexity and data limitations influenced the spatial and temporal scale chosen for simulations. Post-fire model adaptations to simulate on-site soil erosion are well established, mainly using empirical equations extensively calibrated in the literature. At the watershed level, however, physical and process-based models are preferred for their ability to simulate more complex burned area characteristics. Future research should focus on the simulation of the ash transport and the development of integrated modelling frameworks, combining watershed and aquatic ecosystem models to link the on and off-site impacts of fires.

Simulation mathematical modeling of hydroecological monitoring of water resources using space images of the Earth

Modeling of aquatic ecosystems is the basis for solving many practical problems. These problems are related to increasing the productivity of water bodies, improving the quality of water in them and the implementation of water protection measures in catchment areas. The study is based on the integration of materials from space images of the Earth and terrestrial values of the ecological index of water quality to assess the state of aquatic ecosystems, which provides sufficient data to assess the parameters of water pollution. The issues of construction of resource-oriented scenarios of nature management based on the balance of water consumption and reproduction are considered. The role and place of mathematical modeling in the system of ecological monitoring are shown, namely that the information technology of process scenario management allows to maintain the balance of water consumption and reproduction of water resources. Integrated dynamic models of Kyiv Reservoir systems have been built, focused on establishing a balance of water consumption and reproduction. A systematic approach was used to build the models, in which the economic goals of water consumption are made dependent on the ecological state. In accordance with the principle of dynamic balance, which postulates the desire of a complex system to dynamic equilibrium with variable external forces, the creation of the method proposed a universal model of adaptive balance of the system of interdependent processes. As an example of using a systematic management methodology, consider the problem of finding a balance between the volume of water consumption and the volume of their reproduction. This balance, maintained through environmental measures, is represented by a conceptual model of the ecological and economic system. Simulation experiments with the model of adaptive balance of water resources impacts were performed. The main advantage of such computer control technologies is the wide possibility to carry out simulation experiments and choose from an ensemble of possible process scenarios that meet the target guidelines for sustainable development.

Water Ecosystems Tool (WET) 1.0 – a new generation of flexible aquatic ecosystem model

Abstract. We present the Water Ecosystems Tool (WET) – a new generation of open-source, highly customizable aquatic ecosystem model. WET is a completely modularized aquatic ecosystem model developed in the syntax of the Framework for Aquatic Biogeochemical Models (FABM), which enables coupling to multiple physical models ranging from zero to three dimensions, and is based on the FABM–PCLake model. The WET model has been extensively modularized, empowering users with flexibility of food web configurations, and incorporates model features from other state-of-the-art models, with new options for nitrogen fixation and vertical migration. With the new structure, features and flexible customization options, WET is suitable in a wide range of aquatic ecosystem applications. We demonstrate these new features and their impacts on model behavior for a temperate lake for which a model calibration of the FABM–PCLake model was previously published and discuss the benefits of the new model.

An automatic lake-model application using near-real-time data forcing: development of an operational forecast workflow (COASTLINES) for Lake Erie

Abstract. For enhanced public safety and water resource management, a three-dimensional operational lake hydrodynamic forecasting system, COASTLINES (Canadian cOASTal and Lake forecastINg modEl System), was developed. The modeling system is built upon the three-dimensional Aquatic Ecosystem Model (AEM3D) model, with predictive simulation capabilities developed and tested for a large lake (i.e., Lake Erie). The open-access workflow derives model forcing, code execution, post-processing, and web-based visualization of the model outputs, including water level elevations and temperatures, in near-real time. COASTLINES also generates 240 h predictions using atmospheric forcing from 15 and 25 km horizontal-resolution operational meteorological products from the Environment Canada Global Deterministic Forecast System (GDPS). Simulated water levels were validated against observations from six gauge stations, with model error increasing with forecast horizon. Satellite images and lake buoys were used to validate forecast lake surface temperature and the water column thermal stratification. The forecast lake surface temperature is as accurate as hindcasts, with a root-mean-square deviation <2 ∘C. COASTLINES predicted storm surges and up-/downwelling events that are important for coastal flooding and drinking water/fishery management, respectively. Model forecasts are available in real time at https://coastlines.engineering.queensu.ca/ (last access: January 2022​​​​​​​). This study provides an example of the successful development of an operational forecasting workflow, entirely driven by open-access data, that may be easily adapted to simulate aquatic systems or to drive other computational models, as required for management and public safety.

Climate Games, the Blue Humanities, and Listening to the Deep-Sea Ecosystems in Games in a Time of Ecological Crisis

ABSTRACTAbzû, released in 2016 by Giant Squid Studios, is an underwater adventure exploration game where the player plays as an unspeaking protagonist, known as the Diver, who communicates only through sonic “pings” as they navigate the unexplored depths of the ocean. In this discussion of the aquatic ecosystem modeling and sound design of Abzû and its relationship to narrative and game mechanics, the author applies approaches from the blue humanities and Stefan Helmreich’s concept of the “alien ocean,” a term he reclaims from the marine biologists who used it to describe the “strangeness” of the creatures they were investigating, to address how players interact with and come to understand in-game deep-sea soundscapes that are beyond human perception and experienced by playing as an AI exploration entity. The article considers how inequities in power and agency are translated into constructions of knowledge and the epistemological framing and scoring the nonhuman “other” (and what that communicates about being human) in environmental art that explores environments uninhabited by human life. In Abzû, the author looks at what the framework of the blue humanities and blue media can shape the discussion of ecological game sound design.

Hitting the sweet spot of complexity: Reasons why the development of new custom-tailored models is still warranted and should be encouraged in aquatic sciences

Process-based aquatic ecosystem models are increasingly being developed and used in freshwater ecology and other aquatic sciences, as they are powerful tools to gain a mechanistic understanding of ecological processes and inform policy and decision making in environmental management. Over the last decades, not only have these models increased considerably in number, but also in their degree of complexity, which can improve predictive capacity. Nevertheless, it is also because of the higher degree of complexity of many models of current widespread use, that not all the hypotheses and assumptions upon which they have been built are always met by the relatively simple experiments that characterise fundamental ecological research. This is true for both laboratory experiments and those carried out outdoors, under semi-controlled conditions. Examples of the latter are the mesocosms experiments through which several novel questions are nowadays being addressed. In this article, we present our views on why the development of new custom-tailored aquatic ecosystem models of varying degrees of complexity is still very much warranted and should, therefore, be encouraged despite arguments in favour of always increasing complexity and against the creation of new models that are largely based on previously published ones (‘reinventing the wheel’). Deciding on the right complexity level should be linked to the biological organisation levels that are relevant to the specific research questions, and to how much knowledge on the subject is already available. Spatial and temporal scales are additional factors that a modeller should weigh in when deciding on the complexity of a model. To address these needs in the long term, the modelling community needs to grow. Training a new generation of model developers will not only benefit other scientists to better design future experiments but will also facilitate interdisciplinary research and teamwork, approaches such as ensemble modelling, as well as the communication of science to managers and many other stakeholders.

Modeling mixoplankton along the biogeochemical gradient of the Southern North Sea

The ecological importance of mixoplankton within marine protist communities is slowly being recognized. However, most aquatic ecosystem models do not include formulations to model a complete protist community consisting of phytoplankton, protozooplankton and mixoplankton. We introduce PROTIST, a new module for the aquatic ecosystem modelling software Delft3D-WAQ that can model a protist community consisting of two types of phytoplankton (diatoms and green algae), two types of mixoplankton (constitutive mixoplankton and non-constitutive mixoplankton) and protozooplankton. We employed PROTIST to further explore the hypothesis that the biogeochemical gradient of inorganic nutrient and suspended sediment concentrations drives the observed occurrence of constitutive mixoplankton in the Dutch Southern North Sea. To explore this hypothesis, we used 11 1D-vertical aquatic ecosystem models that mimic the abiotic conditions of 11 routine monitoring locations in the Dutch Southern North Sea. Our models result in plausible trophic compositions across the biogeochemical gradient as compared to in-situ data. A sensitivity analysis showed that the dissolved inorganic phosphate and silica concentrations drive the occurrence of constitutive mixoplankton in the Dutch Southern North Sea.