Aquatic Research Research Articles

Design and Development of a Comprehensive, Robust and KM-Scalable Database (Backend) for a PILI (Canarium ovatum Engl.) Information System

This paper presents the results of efforts to design and develop a comprehensive repository of knowledge for Pili (Canarium ovatum Engl.), an endemic crop in the Bicol Region known for its various uses. This study, in general, responds to the challenges entailed in the national government’s having identified “PILI” as the flagship commodity of the Bicol region. In particular, it seeks to address the dearth of accessible knowledge on the Pili industry. Enabling users around the world to become acquainted with this endemic crop. The database’s initial goal is to provide key facts on population dynamics of Pili crop (Canarium ovatum Engl.) varieties and is designed and structured towards knowledge management (KM) buildup. Many similar information systems applied in agriculture were consulted and visited by the researchers in the literature such as the International Rice Research Institute (IRRI’s) comprehensive crop information system [1], and the more recent Mango Resource Information System [2] which was developed for the management of the phenotypic, genetic, molecular to chemical and other information on mango cultivars. The breadth and depth of information in the database are designed to cater to the different needs of diverse groups of stakeholders (farmers, vendors, processors, scientists, researchers, policy-makers, teachers, and students). Its various applications range from basic Pili bio-ecological data management to e-commerce and analytics. This Pili database covers the more than 14 NSIC (National Seed Industry Council) accredited pili varieties, 200 accessions compiled from more than 150 references in partnership with more than 10 collaborators, and more than 500 pictures taken from different cultivars in the Bicol region. At present, the database has 180 tables, enriched by the collection of various Pili related information ranging from its nomenclature, accession, NSIC registration, distribution, morphological characteristics, genetic resources, geo-mapping and characterization, propagation techniques, emerging diseases, growth and yield response, postharvest processing, to products, e-commerce, data analytics and other related data present in different cultivars. The database is normalized to handle complex queries needed to generate knowledge not only for Philippine Council for Agriculture, Aquatic and Natural Resources Research and Development (PCAARRD) and its member-agencies but for Pili farmers/producers, vendors, enthusiasts, retail outlets, and the market as a whole. It is designed with flexibility in mind to interface and interconnect/link with other PCAARRD systems for a dynamic web of knowledge. It is believed that making information and data on Pili publicly available will enliven and invigorate the stakeholders in this industry and help boost yield/production, encourage more research and development efforts, promote innovation, step up marketability of various pili-related products, and consequently improve the living conditions of marginalized farmers and vendors.

Ecological interaction between cyanobacterial blooms and freshwater fish

Fish are an integral component of aquatic ecosystems and play important roles in maintaining ecosystem stability. However, fish have recently been under great threat due to the deterioration of aquatic environments and the loss of suitable habitats. Due to the intensification of global warming and water eutrophication, the frequency and duration of cyanobacteria blooms have been increasing. Cyanobacteria blooms are often accompanied by cyanotoxin and taste-and-odor substance productions which threaten fish survival and fishery economics. However, the ecological interaction between cyanobacteria and fish is multifaceted. Biomanipulation techniques using fish to regulate excessive cyanobacteria growth have achieved certain effects in the bioremediation of eutrophic water bodies. Therefore, a comprehensive assessment of the impacts of cyanobacteria blooms on freshwater fish populations and the control and driving effects of fish on cyanobacteria are necessary to protect freshwater ecosystems. This study systematically analyzes the effect of cyanobacteria blooms on freshwater fisheries, toxicological effects of harmful cyanobacteria on fish, and the ecological regulation of fish on cyanobacteria. Accordingly, we have proposed future research directions. More attention should be paid to the impacts of cyanobacteria blooms on the physiology, ecology, and behavior of fish, and other animal populations. It is necessary to further clarify whether fish miniaturization and a decline in fish species diversity are directly related to cyanobacteria blooms. Fish exposure to cyanobacteria blooms is a complex topic because aquatic animals are not only exposed to cyanotoxins but also to cyanobacterial cells and lysates which contain various compounds. Thus, the overall effect of complex cyanobacteria biomass or in situ cyanobacteria blooms on fish and the corresponding aquatic ecological risk assessment probably will be the focus of future aquatic research. Moreover, a comprehensive examination of the impact of taste-and-odor substances produced by cyanobacteria on fishery products is also required. Biomanipulation, including traditional and non-traditional techniques, is one of the effective tools to control cyanobacteria blooms. Biomanipulation for water environment restoration can be affected by several factors including geographical characteristics, lake and reservoir morphology, algal composition, stocking mode, and biological community structure. Therefore, the feasibility of implementing biomanipulation should depend on the environmental and biological characteristics of water bodies and specific practices during decision-making processes. Previous studies suggest that combining bivalve and filter-feeding fish may enhance the bioremediation effect of algae but their synergistic effects and effectiveness in natural lakes remain to be further verified. Therefore, this study aims to provide a scientific basis to assess the ecological risk of cyanobacteria blooms, protect freshwater fish, and improve aquatic environments.

Standardization of instantaneous fluoroprobe measurements of benthic algal biomass and composition in streams

Fluoroprobes, such as BenthoTorch, offer a relatively rapid in situ method for monitoring benthic algae, provide new opportunities for aquatic ecological research, and enable early warning of algal proliferation in municipal water supplies. Currently, however, BenthoTorch is limited for the measurement of heterogeneous samples, and homogenizing samples is rather difficult. In this study, we compared chlorophyll-a (Chl-a) measurements between BenthoTorch and standard laboratory methods to quantify and describe the biomass and biovolume proportion of benthic algae growing on artificial and natural substrates. We used the difference in Chl-a measurements between these methods (n = 359) to evaluate the effects of environmental variables. Moreover, we used artificial and natural substrates to determine whether either of them reduced variation in BenthoTorch measurements. There was a general concordance in measurements between the two methods, but this agreement was stronger for artificial substrates. Artificial substrates also led to significantly less variation in BenthoTorch readings compared with natural substrates. This may be attributed to the formation of relatively thin algal mats on artificial substrates. To enable early warning of algal proliferation in an aquatic ecosystem, we recommend the use of BenthoTorch and artificial substrates combined with appropriate calibration using standard laboratory methods. The ability of BenthoTorch to produce instantaneous results facilitates replicate collection, which reduces sampling error and increases sampling area on the same day. Despite substantial variation in readings on natural substrates, BenthoTorch enables relatively rapid measurements, facilitating easy monitoring of large areas. Therefore, BenthoTorch may be worth incorporating into aquatic ecosystem studies, depending on the specific research questions.

Sample Preparation Techniques for the Analysis of Microplastics in Soil—A Review

Although most plastic pollution originates on land, current research largely remains focused on aquatic ecosystems. Studies pioneering terrestrial microplastic research have adapted analytical methods from aquatic research without acknowledging the complex nature of soil. Meanwhile, novel methods have been developed and further refined. However, methodical inconsistencies still challenge a comprehensive understanding of microplastic occurrence and fate in and on soil. This review aims to disentangle the variety of state-of-the-art sample preparation techniques for heterogeneous solid matrices to identify and discuss best-practice methods for soil-focused microplastic analyses. We show that soil sampling, homogenization, and aggregate dispersion are often neglected or incompletely documented. Microplastic preconcentration is typically performed by separating inorganic soil constituents with high-density salt solutions. Not yet standardized but currently most used separation setups involve overflowing beakers to retrieve supernatant plastics, although closed-design separation funnels probably reduce the risk of contamination. Fenton reagent may be particularly useful to digest soil organic matter if suspected to interfere with subsequent microplastic quantification. A promising new approach is extraction of target polymers with organic solvents. However, insufficiently characterized soils still impede an informed decision on optimal sample preparation. Further research and method development thus requires thorough validation and quality control with well-characterized matrices to enable robust routine analyses for terrestrial microplastics.

Engaging stakeholders across a socio-environmentally diverse network of water research sites in North and South America

Maintaining and restoring freshwater ecosystem services in the face of local and global change requires adaptive research that effectively engages stakeholders. However, there is a lack of understanding and consensus in the research community regarding where, when, and which stakeholders should be engaged and what kind of researcher should do the engaging (e.g., physical, ecological, or social scientists). This paper explores stakeholder engagement across a developing network of aquatic research sites in North and South America with wide ranging cultural norms, social values, resource management paradigms, and eco-physical conditions. With seven sites in six countries, we found different degrees of engagement were explained by differences in the interests of the stakeholders given the history and perceived urgency of water resource problems as well as differences in the capacities of the site teams to effectively engage given their expertise and resources. We categorized engagement activities and applied Hurlbert and Gupta's split ladder of participation to better understand site differences and distill lessons learned for planning comparative socio-hydrological research and systematic evaluations of the effectiveness of stakeholder engagement approaches. We recommend research networks practice deliberate engagement of stakeholders that adaptively accounts for variations and changes in local socio-hydrologic conditions. This, in turn, requires further efforts to foster the development of well-integrated research teams that attract and retain researchers from multiple social science disciplines and enable training on effective engagement strategies for diverse conditions.

Aquatic Insects Are Dramatically Underrepresented in Genomic Research.

Simple SummaryThe genome is the basic evolutionary unit underpinning life on Earth. Knowing its sequence, including the many thousands of genes coding for proteins in an organism, empowers scientific discovery for both the focal organism and related species. Aquatic insects represent 10% of all insect diversity, can be found on every continent except Antarctica, and are key components of freshwater ecosystems. However, aquatic insect genome biology lags dramatically behind that of terrestrial insects. If genomic effort was spread evenly, one aquatic insect genome would be sequenced for every ~9 terrestrial insect genomes. Instead, ~24 terrestrial insect genomes have been sequenced for every aquatic insect genome. A lack of aquatic genomes is limiting research progress in the field at both fundamental and applied scales. We argue that the limited availability of aquatic insect genomes is not due to practical limitations—small body sizes or overly complex genomes—but instead reflects a lack of research interest. We call for targeted efforts to expand the availability of aquatic insect genomic resources to empower future research.Aquatic insects comprise 10% of all insect diversity, can be found on every continent except Antarctica, and are key components of freshwater ecosystems. However, aquatic insect genome biology lags dramatically behind that of terrestrial insects. If genomic effort was spread evenly, one aquatic insect genome would be sequenced for every ~9 terrestrial insect genomes. Instead, ~24 terrestrial insect genomes have been sequenced for every aquatic insect genome. This discrepancy is even more dramatic if the quality of genomic resources is considered; for instance, while no aquatic insect genome has been assembled to the chromosome level, 29 terrestrial insect genomes spanning four orders have. We argue that a lack of aquatic insect genomes is not due to any underlying difficulty (e.g., small body sizes or unusually large genomes), yet it is severely hampering aquatic insect research at both fundamental and applied scales. By expanding the availability of aquatic insect genomes, we will gain key insight into insect diversification and empower future research for a globally important taxonomic group.

Outstanding L&O Associate Editors and Reviewers

Outstanding <i>L&amp;O</i> Associate Editors and Reviewers

Boundary element method to analyze acoustic scattering from a coupled swimbladder-fish body configuration

A model for computing acoustic scattering by swimbladdered fish is presented. The effect of acoustic coupling between the fish tissue and the swimbladder is included. The swimbladder is considered a gas-filled object whereas the fish tissue is assumed to behave as a homogeneous fluid. Mathematically, this corresponds to considering the problem of two penetrable scatterers immersed in a homogeneous medium, one of which is wholly embedded in the other. The model is formulated in the frame of boundary integral equations whose solution is achieved using the Boundary Element Method (BEM) for a planar triangle mesh. The numerical implementation is verified against benchmark solutions reported in the literature. The model is then applied to a specimen of Argentine hake (Merluccius hubbsi), whose morphometry was determined by CT scanning of a frozen sample, for evaluating its forward and backscattering responses. From the acoustic scattering viewpoint, the swimbladder is considered as a gas-filled object while the flesh constituting the fish body acts like a weak scatterer. The numerical results suggest the swimbladder and the fish body responses, when fully coupled, can lead to substantial differences with respect to the simplified models normally in use in the area of aquatic ecosystem research.

Periphyton, bivalves and fish differentially accumulate select pharmaceuticals in effluent-dependent stream mesocosms

Pharmaceuticals and other ionizable contaminants from municipal wastewater treatment plant effluent can bioaccumulate in fish, particularly in effluent dominated and dependent systems in semi-arid and arid regions. However, invertebrate bioaccumulation of these compounds has been less studied. Using municipal wastewater effluent as source water in outdoor stream mesocosms to simulate effluent-dependent lotic systems, we examined bioaccumulation of several widely-used pharmaceuticals including acetaminophen (nonsteroidal anti-inflamatory), caffeine (stimulant), carbamazepine (anti-epileptic), diltiazem (calcium channel blocker), diphenhydramine (anti-histamine), fluoxetine (anti-depressant), norfluoxetine (anti-depressant metabolite), and sertraline (anti-depressant) in freshwater clams (Corbicula fluminea), periphyton and stoneroller minnows (Campostoma anomalum), a commonly studied grazer in stream ecology, during a replicated outdoor stream mesocosm study at the Baylor Experimental Aquatic Research facility. Target analytes were determined in tissues, source effluent and stream water by isotope dilution LC-MS/MS. After an 8-day uptake period, clams accumulated a number of pharmaceuticals, including acetaminophen, carbamazepine, diltiazem, diphenhydramine, fluoxetine, norfluoxetine and sertraline with maximum concentrations reaching low μg/kg. We observed uptake rates in clams for acetaminophen at 2.8 μg/kg per day, followed by diphenhydramine (1.2 μg/kg per day) and carbamazepine (1.1 μg/kg per day). Caffeine, carbamazepine, diltiazem and diphenhydramine were measured in periphyton. Diphenhydramine was the only compound detected in all matrices, where bioaccumulation factors (BAFs) were elevated in bivalves (1631 ± 589 L/kg), compared to stoneroller minnows (247 ± 84 L/kg) and periphyton (315 ± 116 L/kg). Such BAF variability across multiple biological matrices highlight the need to understand bioaccumulation differences for ionizable contaminants among freshwater biota, including threatened and endangered species (e.g., unionids), commercially important bivalves (e.g., estuarine and marine bivalves), and fish.

MEDUSA: A Multi-Environment Dual-Robot for Underwater Sample Acquisition

Aerial-aquatic robots possess the unique ability of operating in both air and water. However, this capability comes with tremendous challenges, such as communication incompatibility, increased airborne mass, potentially inefficient operation in each of the environments and manufacturing difficulties. Such robots, therefore, typically have small payloads and a limited operational envelope, often making their field usage impractical. We propose a novel robotic water sampling approach that combines the robust technologies of multirotors and underwater micro-vehicles into a single integrated tool usable for field operations. The proposed solution encompasses a multirotor capable of landing and floating on the water, and a tethered mobile underwater pod that can be deployed to depths of several meters. The pod is controlled remotely in three dimensions and transmits video feed and sensor data via the floating multirotor back to the user. The `dual-robot' approach considerably simplifies robotic underwater monitoring, while also taking advantage of the fact that multirotors can travel long distances, fly over obstacles, carry payloads and manoeuvre through difficult terrain, while submersible robots are ideal for underwater sampling or manipulation. The presented system can perform challenging tasks which would otherwise require boats or submarines. The ability to collect aquatic images, samples and metrics will be invaluable for ecology and aquatic research, supporting our understanding of local climate in difficult-to-access environments [Video attachment: https://youtu.be/v4xWmEHUSM4].

Quantitation and localization of beta-blockers and SSRIs accumulation in fathead minnows by complementary mass spectrometry analyses

Beta-blockers and selective serotonin reuptake inhibitors (SSRIs) enter the environment through the improper disposal of drugs in garbage, sinks, or toilets as well as via excretion after their intended use. Beta-blockers and SSRIs are resistant to biodegradation and highly water soluble, leading to limited removal capabilities by wastewater treatment plants. As a result, these compounds can easily enter the aquatic environment in a biologically active state, posing risks to the behavior, anatomy, and physiology of aquatic organisms through exposure. However, there is insufficient research on the effects of beta-blockers on aquatic vertebrates to have a complete understanding of the impact of beta-blocker pollution on aquatic organisms. Exposing fathead minnows at environmentally-relevant concentrations allows for an accurate representation of how beta-blockers and SSRIs affect and accumulate in aquatic vertebrates. Singular exposures to two beta-blockers and two selective serotonin reuptake inhibitors (SSRIs) at seven days modeled how pollution affects aquatic wildlife during acute exposure events. After exposure, the entire organism was analyzed quantitatively by liquid chromatography mass spectrometry and qualitatively by matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI-MSI). Imaging allowed for the determination of the part of the organism in which the drugs were accumulating. Results showed that after seven days of exposure there was accumulation of both the beta-blockers and SSRIs in the fathead minnows. This data represents the first application of LC-MS quantitation guided by MALDI-MSI in aquatic toxicology-type research in environmental analytical chemistry.

Effects of downwash during unmanned aircraft system‐assisted water sampling on water mass structure directly below the UAS

AbstractIn recent years, unmanned aircraft system (UAS) have played an increasing role in fields such as topographic mapping using optical cameras and thermal mapping using infrared cameras in aquatic environmental research. UAS‐assisted water sampling has important advantages, such as reducing labor, increasing sampling speed, and enabling sample collection from as‐yet unexplored lakes and marshes. However, downwash effects on water masses have not yet been evaluated. We conducted two experiments to evaluate the impact of UAS downwash on water mass characteristics. In the first experiment, we used temperature sensors and thermal imaging cameras to show that downwash generates bottom‐water upwelling. The results of this experiment are consistent with our hypothesized mechanism for water mass perturbation. In the second experiment, we directly measured downwash speeds and used the data to recommend a maximum downwash speed of 4.0 m s−1 for UAS‐assisted water sampling. However, we caution that even slower downwash speeds may be required for certain field conditions and research questions. Our results showed that the ongoing development of UAS‐assisted water sampling must include efforts to measure and minimize downwash.

Quantification and Speciation of Trace Metals under Pollution Impact: Case Study of a Subarctic Lake

Monitoring the quantity and quality of metals in lake water is a major part of assessing water toxicity. A fundamental aspect of geochemical monitoring studies is the evaluation of the equilibrium distribution of metal speciation in water and the influence of environmental conditions on this process. It is important to understand the difference between the behavior of nanoparticles, dissolved particles, colloid particles, and suspended particles. This study involved environmental aquatic chemistry research and the assessment of the geochemical processes of metal speciation in an arctic lake in the metallurgical waste zone and other areas where natural processes prevail. Consecutive and parallel membrane filtration methods were used to compare the results of water analysis in Imandra Lake. The membrane pore sizes were 8, 1.2, 0.45, and 0.2 µm. The following filtrate characteristics were used: microfiltration-based mechanical suspension and oxidized contaminants (&gt;8, 1.2, 0.45, 0.2, 0.1 μm), and ultrafiltration-based colloids, bacteria, viruses, etc. (less than 0.1 μm). Industrial effluents led to the formation of higher concentrations of elements (Ni, Cu, and Pb) in their labile forms. In the wastewater-mixing zone, the concentrations of most elements were evenly distributed in depth. In more distant areas, we found a significant increase in the concentration of elements in the near-bottom horizon in comparison with the surface water (Fe by more than three times). The obtained results showed that numerous elements had diverse distributions by speciation in the points located closer to the source of wastewater. This indicated the significant influence of the adsorption process on the system balance of elements such as Fe, Cu, and rare earth elements. The impact of the regional geochemical and anthropogenic speciation and the possible influence of climatic factors on the distribution of speciation were determined.

FishCam: A low-cost open source autonomous camera for aquatic research.

We describe the "FishCam", a low-cost ( 500 USD) autonomous camera package to record videos and images underwater. The system is composed of easily accessible components and can be programmed to turn ON and OFF on customizable schedules. Its 8-megapixel camera module is capable of taking 3280×2464-pixel images and videos. An optional buzzer circuit inside the pressure housing allows synchronization of the video data from the FishCam with passive acoustic recorders. Ten FishCam deployments were performed along the east coast of Vancouver Island, British Columbia, Canada, from January to December 2019. Field tests demonstrate that the proposed system can record up to 212h of video data over a period of at least 14days. The FishCam data collected allowed us to identify fish species and observe species interactions and behaviors. The FishCam is an operational, easily-reproduced and inexpensive camera system that can help expand both the temporal and spatial coverage of underwater observations in ecological research. With its low cost and simple design, it has the potential to be integrated into educational and citizen science projects, and to facilitate learning the basics of electronics and programming.

Aquatic Microplastic Research—A Critique and Suggestions for the Future

While there are numerous papers on microplastics (mps) being published every week, there is a need for improvement for the field to mature. The papers reporting numbers found in water bodies cannot be compared because there are no standard methods for collection and analysis. It is clear that using nets for sampling misses most of the microfibers, which are the most abundant form when whole water samples are analyzed, and that microscopic identification has a very high error rate compared to chemical analytical equipment which can also identify the polymers. It is clear that most animals studied eat mps; we should learn what attracts the animals to the mps and what proportion pass right through and are defecated vs those that move into the tissues. It is considered that mps are a vector for transfer of toxic chemicals into the food chain. Let us investigate to what degree what proportion of contaminants are removed in the digestive system vs. staying bound tightly to the mps. Experimental studies should also use environmentally relevant doses and the shapes and sizes of mps that are most abundant in the environment.

Aquatic food web research in mesocosms: a literature survey

Food web research feeds ecology with elementary theoretical concepts that need controlled experimental testing. Mesocosm facilities offer multiple ways to execute experimental food web research in a rigorous way. We performed a literature survey to overview food web research implementing the mesocosm approach. Our goal was to summarise quantitatively how the mesocosm approach has formerly been used and question how to best utilise mesocosms for the emerging topics in food web research in the future. We suggest increasing the number of replicates, extending the duration of the experiments, involving higher trophic levels and addressing the combined effects of multiple stressors.

Message from the Executive Director Interview with Dave Hambright, Editor‐in‐Chief, Limnology and Oceanography

Message from the Executive Director Interview with Dave Hambright, Editor‐in‐Chief, <i>Limnology and Oceanography</i>

Key Concepts in Polar Science: Coming to Consensus on the Essential Polar Literacy Principles

Current is the peer-reviewed journal of the National Marine Educators Association. It features lively, in-depth articles and activities relating to all aspects of the world of water. Articles explore the latest in marine and aquatic education research, ocean literacy, classroom and free-choice learning activities, marine science, art, maritime history and literature.

Accelerated Passive Dosing of Hydrophobic Complex Mixtures-Controlling the Level and Composition in Aquatic Tests.

Petroleum products and essential oils are complex mixtures of hydrophobic and volatile chemicals and are categorized as substances of unknown or variable composition, complex reaction products, or biological materials (UVCBs). In aquatic testing and research of such mixtures, it is challenging to establish initial concentrations without the addition of cosolvents, to maintain constant concentrations during the test, and to keep a constant mixture composition in dilution series and throughout test duration. Passive dosing was here designed to meet these challenges by maximizing the surface area (Adonor/Vmedium = 3.8 cm2/mL) and volume (Vdonor/Vmedium > 0.1 L/L) of the passive dosing donor in order to ensure rapid mass transfer and avoid donor depletion for all mixture constituents. Cracked gas oil, cedarwood Virginia oil, and lavender oil served as model mixtures. This study advances the field by (i) showing accelerated passive dosing kinetics for 68 cracked gas oil constituents with typical equilibration times of 5-10 min and for 21 cederwood Virginia oil constituents with typical equilibration times < 1 h, (ii) demonstrating how to control mixture concentration and composition in aquatic tests, and (iii) discussing the fundamental differences between solvent spiking, water-accommodated fractions, and passive dosing.

Beyond the trends: The need to understand multiannual dynamics in aquatic ecosystems

Beyond the trends: The need to understand multiannual dynamics in aquatic ecosystems