Linking tidal wetland vegetation mosaics to micro-topography and hydroperiod in a tropical estuary.

Although saltmarshes are critical coastal ecosystems they are threatened by human activities and sea-level rise (SLR). Long-term restoration and management strategies are often hampered by an insufficient understanding of the past, present, and future processes that influence tidal wetland functionality and change. As understanding vegetation distribution in relation to elevation and tidal hydroperiod is often the basis of restoration and management decisions, this study investigated the relationships between micro-topography, tidal hydroperiod, and the distribution of saltmarshes, mangroves, and unvegetated flats in a tropical estuary situated within a Great Barrier Reef Catchment in North Queensland, Australia. A combination of high-resolution unattended-aerial-vehicle (UAV)-derived digital elevation model (DEMs) and land cover coupled with 2D hydrodynamic modelling was used to investigate these aspects. Zonation was more complex than generally recognised in restoration and legislation, with overlapping distribution across elevation. Additionally, although each type of tidal wetland cover had distinct mean hydroperiods, and elevation and hydroperiods were strongly correlated, elevation explained only 15% of the variability in tidal wetland cover distribution. This suggests that other factors (e.g., groundwater dynamics) likely contribute to tidal wetland cover zonation patterns. These findings underline that simplistic rules in the causality of tidal wetlands need to be applied with caution. Their applicability in management and restoration are likely to vary depending on contexts, as observed in our study site, with varying environmental and biological factors playing important roles in the distribution patterns of tidal wetland components. We also identified strong monthly variability in tidal hydroperiods and connectivity experienced by each tidal wetland cover (e.g., 10.26% of succulent saltmarshes were inundated during lower-than-average tides compared to 66% in higher than-average tides), highlighting the importance of integrating temporal dynamics in tidal wetland research and management. Additionally, we explored the potential effects of sea-level rise (SLR) on the tidal hydroperiods and connectivity of our study site. The results show that the inundation experienced by each tidal wetland cover may increase importantly if vegetation does not keep up with SLR (e.g., under a 0.8 m sea level scenarios, mean maximum depth of succulent saltmarsh in higher-than-average tides is 184.1 mm higher than the current mean-maximum inundation depth of mangroves). This underlines the importance of acquiring detailed spatio-temporally resolved data to enable the development of robust long-term and adaptive saltmarsh management strategies. Our results are discussed from a management and restoration perspective. We highlight the uncertainties and complexities in understanding the processes influencing tidal wetland functionality, and hence, their management and restoration prospects.

Using a combination of quantitative culture, molecular, and infrastructure data to rank potential sources of fecal contamination in Town Creek Estuary, North Carolina.

Estuarine water quality is declining worldwide due to increased tourism, coastal development, and a changing climate. Although well-established methods are in place to monitor water quality, municipalities struggle to use the data to prioritize infrastructure for monitoring and repair and to determine sources of contamination when they occur. The objective of this study was to assess water quality and prioritize sources of contamination within Town Creek Estuary (TCE), Beaufort, North Carolina, by combining culture, molecular, and geographic information systems (GIS) data into a novel contamination source ranking system. Water samples were collected from TCE at ten locations on eight sampling dates in Fall 2021 (n = 80). Microbiological water quality was assessed using US Environmental Protection Agency (U.S. EPA) approved culture-based methods for fecal indicator bacteria (FIB), including analysis of total coliforms (TC), Escherichia coli (EC), and Enterococcus spp. (ENT). The quantitative microbial source tracking (qMST) human-associated fecal marker, HF183, was quantified using droplet digital PCR (ddPCR). This information was combined with environmental data and GIS information detailing proximal sewer, septic, and stormwater infrastructure to determine potential sources of fecal contamination in the estuary. Results indicated FIB concentrations were significantly and positively correlated with precipitation and increased throughout the estuary following rainfall events (p < 0.01). Sampling sites with FIB concentrations above the U.S. EPA threshold also had the highest percentages of aged, less durable piping materials. Using a novel ranking system combining concentrations of FIB, HF183, and sewer infrastructure data at each site, we found that the two sites nearest the most aged sewage infrastructure and stormwater outflows were found to have the highest levels of measurable fecal contamination. This case study supports the inclusion of both traditional water quality measurements and local infrastructure data to support the current need for municipalities to identify, prioritize, and remediate failing infrastructure.

Seasonality, rather than estuarine gradient or particle suspension/sinking dynamics, determines estuarine carbon distributions.

Estuaries are important components of the global carbon cycle; exchanging carbon between aquatic, atmospheric, and terrestrial environments, representing important loci for blue carbon storage and greenhouse gas emissions. However, how estuarine gradients affect sinking/suspended particles, and dissolved organic matter dynamic interactions remains unexplored. We fractionated suspended/sinking particles to assess and characterise carbon fate differences. We investigated bacterial colonisation (SYBR Green I) and exopolymer concentrations (TEP/CSP) with microscopy staining techniques. C/H/N and dry weight analysis identified particle composition differences. Meanwhile, nutrient and carbon analysis, and excitation and emission matrix evaluations with a subsequent parallel factor (PARAFAC) analysis characterised dissolved organic matter. The lack of clear salinity driven patterns in our study are presumably due to strong mixing forces and high particle heterogeneity along the estuary, with only density differences between suspended and sinking particles. Elbe estuary particles' organic portion is made up of marine-like (sinking) and terrestrial-like (suspended) signatures. Salinity did not have a significant role in microbial degradation and carbon composition, although brackish estuary portions were more biologically active. Indicative of increased degradation rates, leading to decreased greenhouse gas emissions, which are especially relevant for estuaries, with their disproportionate greenhouse gas emissions. Bacterial colonisation decreased seawards, indicative of decreased degradation, and shifts in microbial community composition and functions. Our findings span diverse strands of research, concerning steady carbon contributions from both marine and terrestrial sources, carbon aromaticity, humification index, and bioavailability. Their integration highlights the importance of the Elbe estuary as a model system, providing robust information for future policy decisions affecting dissolved and particulate matter dynamics within the Elbe Estuary.

Anthropogenic-induced ecological risks on marine ecosystems indicated by characterizing emerging pollutants in Pearl River Estuary, China.

Anthropogenic Contaminants of Emerging Concern (CECs) in marine environments have raised significant concerns. Yet, analyses detailing their origins, fate, and environmental effects are limited. This study employs an integrated non-target screening methodology to elucidate CECs existence across 46 sampling sites in the Pearl River Estuary (PRE) of the South China Sea. Assisted by advanced liquid chromatography-high resolution mass spectrometry, we discovered 208 chemicals in six usage categories, with pesticides (33 %) and pharmaceuticals (29 %) predominating. Several CECs drew attention for their consistent detections, profound abundance, and significant ecotoxicities. The wide detection of them at offshore sites further implies that anthropogenic activities may contribute to large-scale contamination. Meanwhile, distinct distribution patterns of CECs across PRE are evident in semi-quantitative results, indicating regional anthropogenic influences. Identified transformation products may establish a novel and non-negligible negative contribution to ecology through elevated environmental toxicities, exemplified by HMMM and atrazine. Based on the ecological risks, we compiled a prioritized list of 21 CECs warranting intensified scrutiny. Our findings indicate the introduction of various CECs into the South China Sea via PRE, emphasizing the urgent necessity for ongoing surveillance of discharged CECs at estuary areas and assessment of their marine ecological consequences.

Assessing petrochemical effluent effect on heavy metal pollution in Musa Estuary: A numerical modeling approach.

The objective of this study is to assess the effect of petrochemical effluent on heavy metal pollutant in the Musa Estuary ecosystem in the North-western region of the Persian Gulf, through numerical modeling. The outfall of 30 petrochemical plants poses a potential threat to the estuary's seawater and sediment quality, environment, and public health. A combined hydrodynamic and ecologic modeling framework is applied to predict the spatial distribution of BOD and hazardous heavy metals in this estuary. MIKE 21 Flow Model (FM) CFD software is applied to simulate the tidal waves hydrodynamics, next to applying the MIKE ECO Lab models to predict the distribution of BOD and heavy metals in ambient water. The accuracy of the modeling framework is validated against measured water level, current speed, and water quality data. The results reveal that the level of lead concentration corresponds with the national standard, while the BOD, arsenic, molybdenum and vanadium exceed the limit in some areas, particularly in the tidal zone. The optimal outlet locations that effectively meet the standard concentrations of the heavy metals in the ambient water of the estuary are determined. The results confirm that the new outlet configuration corresponds with the standards: 0.198 µg/L for arsenic concentrations, 0.182 µg/L for molybdenum, 1.530 µg/L for vanadium, and 1.132 mg/L for BOD, at maximum. This study contributes to the perception of estuarine dynamics and provides practical implications for estuarine sustainable management and pollution control.

Urban and agricultural influences on the coastal dissolved organic matter pool in the Algoa Bay estuaries.

While anthropogenic pollution is a major threat to aquatic ecosystem health, our knowledge of the presence of xenobiotics in coastal Dissolved Organic Matter (DOM) is still relatively poor. This is especially true for water bodies in the Global South with limited information gained mostly from targeted studies that rely on comparison with authentic standards. In recent years, non-targeted tandem mass spectrometry has emerged as a powerful tool to collectively detect and identify pollutants and biogenic DOM components in the environment, but this approach has yet to be widely utilized for monitoring ecologically important aquatic systems. In this study we compared the DOM composition of Algoa Bay, Eastern Cape, South Africa, and its two estuaries. The Swartkops Estuary is highly urbanized and severely impacted by anthropogenic pollution, while the Sundays Estuary is impacted by commercial agriculture in its catchment. We employed solid-phase extraction followed by liquid chromatography tandem mass spectrometry to annotate more than 200 pharmaceuticals, pesticides, urban xenobiotics, and natural products based on spectral matching. The identification with authentic standards confirmed the presence of methamphetamine, carbamazepine, sulfamethoxazole, N-acetylsulfamethoxazole, imazapyr, caffeine and hexa(methoxymethyl)melamine, and allowed semi-quantitative estimations for annotated xenobiotics. The Swartkops Estuary DOM composition was strongly impacted by features annotated as urban pollutants including pharmaceuticals such as melamines and antiretrovirals. By contrast, the Sundays Estuary exhibited significant enrichment of molecules annotated as agrochemicals widely used in the citrus farming industry, with predicted concentrations for some of them exceeding predicted no-effect concentrations. This study provides new insight into anthropogenic impact on the Algoa Bay system and demonstrates the utility of non-targeted tandem mass spectrometry as a sensitive tool for assessing the health of ecologically important coastal ecosystems and will serve as a valuable foundation for strategizing long-term monitoring efforts.

Investigating organic sulfur in estuarine and offshore environments: A combined field and cultivation approach.

Estuarine-offshore sediments accumulate substantial particulate organic matter, containing organic sulfur as a key component. However, the distribution and sources of organic sulfur in such environments remain poorly understood. This study investigated organic sulfur in the Yangtze River Estuary and adjacent East China Sea. Dissolved organic sulfur varied from 0.65 to 1.99 µmol/L (molar S:C 0.006-0.018), while particulate organic sulfur ranged from 0.42 to 2.69 µmol/L (molar S:C 0.007-0.082). Sedimentary organic sulfur exhibited a similar molar S:C ratio (0.014-0.071) to particulate organic sulfur in bottom water, implying that particulate matter deposition is a potential source. Furthermore, sediments exposed to frequent hypoxia harbored significantly higher organic sulfur and S:C values compared to non-hypoxic areas. Laboratory incubation experiments revealed the underlying mechanism: sustained activity of sulfate-reducing bacteria in hypoxic sediments led to a substantial increase in sedimentary organic sulfur (from 15 to 53 µmol/g) within 600 days. This microbially driven sulfurization rendered over 90 % of the organic sulfur resistant to acid hydrolysis. Therefore, this study demonstrates that, alongside particle deposition, microbial sulfurization significantly contributes to organic sulfur enrichment and likely promotes organic matter preservation in estuarine-offshore sediments, particularly under hypoxic conditions. This finding advances our understanding of organic sulfur sources in these vital ecosystems.

Effects of dredging wastewater input history and aquaculture type on greenhouse gas fluxes from mangrove sediments along the shorelines of the Jiulong River Estuary, China.

Dredging wastewater (DW) from aquaculture ponds is a major disturbance factor in mangrove management, and its effects on the greenhouse gas (GHG) fluxes from mangrove sediment remain controversial. In this study, we investigated GHG (N2O, CH4, and CO2) fluxes from mangrove sediment at typical aquaculture pond-mangrove sites that were stimulated by DW discharged for different input histories and from different farm types. The GHG fluxes exhibited differing cumulative effects with increasing periods of DW input. The N2O and CH4 fluxes from mangrove sediment that received DW inputs for 17 y increased by ∼10 and ∼1.5 times, respectively, whereas the CO2 flux from mangrove sediment that received DW inputs for 11 y increased by ∼1 time. The effect of DW from shrimp ponds on the N2O flux was significantly larger than those of DW from fish/crab ponds and razor clam ponds. Moreover, the total global warming potentials (GWPs) at the field sites with DW inputs increased by 29-129% of which the CO2 flux was the main contributor to the GWP (85-96%). N2O as a proportion of CO2-equivalent flux increased from 2% to 12%, indicating that N2O was an important contributor to the increase in GWP. Overall, DW increased the GHG fluxes from mangrove sediments, indicating that the contribution of mangroves to climate warming was enhanced under DW input. It also implies that the carbon sequestration potential of mangrove sediments may be threatened to some extent. Therefore, future assessments of the carbon sequestration capacity of mangroves at regional or global scales should consider this phenomenon.

Distribution of rare earth elements and assessment of anthropogenic gadolinium in estuarine habitats: The case of Loire and Seine estuaries in France.

Rare earth elements (REEs), attractive to society because of their applications in industry, agriculture and medicine, are increasingly released into the environment especially in industrialized estuaries. This study compared the REE distribution in the abiotic compartments: water (dissolved phase (<0.45 µm), suspended particulate matter (SPM)) and sediment of the Loire and Seine estuaries (France). A total of 8 and 6 sites were investigated in the Loire and Seine, respectively, as well as 5 additional offshore sites for the Loire. Total REE concentrations were higher in the Loire for the dissolved phase (93.5 ± 63.3 vs 87.7 ± 16.2 ng/L), SPM (173.9 ± 18.3 vs 114.0 ± 17.8 mg/kg dw) and sediments (198.2 ± 27.9 vs 73.2 ± 27.4 mg/kg dw), explained by higher geogenic inputs. Individual REE contributions along with normalization highlighted heavy REE enrichments and Gd positive anomalies in the dissolved phase of the two estuaries, whereas REE distributions in SPM and sediments followed the natural abundance of the REE classes. The calculated Gd anomalies in the dissolved phase were higher in the Seine (9.7 ± 3.4) than in the Loire (3.0 ± 0.8), corresponding to 88.3 ± 5.1 % and 64.4 ± 11.1 % of anthropogenic Gd. This demonstrates a higher contamination of the Seine estuary, certainly due to the difference in the number of inhabitants between both areas involving different amounts of Gd used in medicine. The offshore sites of Loire showed lower total REE concentrations (55.8 ± 5.8 ng/L, 26.7 ± 38.2 mg/kg dw and 100.1 ± 11.7 mg/kg dw for the dissolved phase, SPM and sediments, respectively) and lower Gd anomalies (1.2 ± 0.2) corresponding to only 13.3 ± 3.9 % of anthropogenic Gd, confirming a contamination from the watershed. This study comparing two major French estuaries provides new data on the REE distribution in natural aquatic systems.

Using monitoring and mechanistic modeling to improve understanding of eutrophication in a shallow New England estuary.

Anthropogenic nutrient loading has resulted in eutrophication and habitat degradation within estuaries. Study of eutrophication in estuaries has often focused on larger systems, while there has been increasing interest in understanding the governing processes in smaller systems. In this study, we incorporate both monitoring data and mechanistic modeling to improve our understanding of eutrophication in a small, shallow New England estuary. High-frequency continuous and discrete water quality samples were collected from 2018 to 2020 along a salinity gradient and at varying depth to provide temporal and spatial resolution of the system. Conditions of this estuary were simulated using the Hydrological Simulation Program - FORTRAN (HSPF) and the Water Quality Analysis Simulation Program (WASP) to develop a mechanistic, numerical fate and transport model. Our findings suggest complex hydrodynamics with three distinct salinity gradients and variability in salinity concentration upstream. Simulated and observed nutrient trends demonstrated decreasing total nitrogen concentration moving downstream and low total phosphorus concentration throughout the system. Simulated nutrient depletion and shading via macroalgae suggest their importance in similar modeling initiatives. Dynamic spatiotemporal variability in dissolved oxygen concentrations ([DO]) resulted from hydrodynamic and ecological processes such as large, rapid swings in phytoplankton. Carbonaceous biological oxygen demand was suggested to be the driver of hypoxia in surface waters, while sediment oxygen demand may drive low [DO] in the stratified, benthic waters. These findings suggest that the coordination of monitoring and modeling was important to understanding the governing mechanisms of eutrophication and hypoxia. Insights from this study could be used to support regional management strategies to increase [DO], improve water clarity, and recover indigenous seagrass beds. This work has the potential to inform future study and management of small, complex estuaries.

Machine learning-based prediction of seasonal hypoxia in eutrophic estuary using capacitive potentiometric sensor.

A hypoxia occurred in eutrophic estuary was predicted using long short-term memory (LSTM) model with prediction time steps (PTSs) of 0, 1, 12, and 24 h. A capacitive potential (CP), which provides quantitative information on dissolved oxygen (DO) concentration, was used as a predictor along with precipitation, tide level, salinity, and water temperature. First, annual changes in DO concentration were clustered in three phases of annual DO trends (oversaturation, depletion, and stable) using k-means clustering. CP was the most influential variable in clustering the DO phases. The LSTM was implemented to predict the DO phases and hypoxia occurrences. In the simultaneous prediction of the depletion phase and hypoxia occurrence with a 12 h PTS, the accuracy was 92.1% using CP along with other variables; it was 3.3% higher than that achieved using variables other than CP. In the case of predicting the depletion phase and hypoxia non-occurrence using CP along with other variables, the accuracy was 61.1%, which was 5.5% higher than that when CP was not used. When using CP along with other variables, the total accuracy was highest for all PTS. Overall, the utilization of CP and machine learning techniques enables accurate predictions of both short-term and long-term hypoxia occurrences, providing us with the opportunity to proactively respond to disasters in aquaculture and environmental management due to hypoxia.

Spatial gradients and molecular transformations of DOM, DON and DOS in human-impacted estuarine sediments.

Dissolved organic matter (DOM) constitutes the most active fraction in global carbon pools, with estuarine sediments serving as significant repositories, where DOM is susceptible to dynamic transformations. Anthropogenic nitrogen (N) and sulfur (S) inputs further complicate DOM by creating N-bearing DOM (DON) and S-bearing DOM (DOS). This study delves into the spatial gradients and transformation mechanisms of DOM, DON, and DOS in Pearl River Estuary (PRE) sediments, China, using combined techniques of UV-visible spectroscopy, Excitation-emission matrix (EEM) fluorescence spectroscopy, Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS), and microbial high-throughput sequencing. Results uncovered a distinct spatial gradient in DOM concentration, aromaticity (SUVA254), hydrophobicity (SUVA260), the content of substituent groups including carboxyl, carbonyl, hydroxyl and ester groups (A253/A203) of chromophoric DOM (CDOM), and the abundances of tyrosine/tryptophan-like protein and humic-like substances in fluorophoric DOM (FDOM). These all decreased from upper to lower PRE, accompanied by a decrease in O3S and O5S components, indicating seaward reduction in the contribution of terrestrial OM, especially anthropogenic inputs. Additionally, sediments exhibited a reduction in molecular diversity (number of formulas) of DOM, DON, and DOS from upper to lower PRE, with molecules tending towards a lower nominal oxidation state of carbon (NOSC) and higher bio-reactivity (MLBL), molecular weight (m/z) and saturation (H/C). While molecular composition of DOM remained similar in PRE sediments, the relative abundance of lignin-like substances decreased, with a concurrent increase in protein-like and lipid-like substances in DON and DOS from upper to lower PRE. Mechanistic analysis identified the joint influence of terrestrial OM, anthropogenic N/S inputs, and microbial processes in shaping the spatial gradients of DOM, DON, and DOS in PRE estuarine sediments. This study contributes valuable insights into the intricate spatial gradients and transformations of DOM, DON, and DOS within human-impacted estuarine sediments.

Effects of fresh-salt water interaction on spatial variations of soil organic carbon in reed wetland of Yellow River Estuary.

Estuarine wetlands exhibit significant interaction between fresh and salt water, with long-term carbon sequestration capability. We set up 60 sampling sites in the reed wetlands of the fresh-salt water interaction zone of the Yellow River Estuary, covering four different zones of the weak-intensity fresh-salt water interaction zone (WIZ), medium-intensity fresh-salt water interaction zone (MIZ), high-intensity interaction fresh-salt water zone (HIZ) and strong-intensity fresh-salt water interaction zone (SIZ). We investigated how fresh-salt water interaction affected the spatial variation of soil organic carbon (SOC) storage. The results showed that the area of reed wetland accounted for 17.8% of the total area of the fresh-salt water interaction zone the Yellow River Estuary, which mainly distributed in the WIZ and MIZ. The SOC content of reed wetland in the fresh-salt water interaction zone ranged from 1.09 to 3.65 g·kg-1, the SOC density was between 1.85-5.84 kg·m-2, and the SOC storage was (17.32±3.64)×104 t. The SOC content and SOC density decreased with increasing fresh-salt water interaction. There were significant differences in surface SOC content between different subzones of the fresh-salt water interaction zone. The surface SOC content decreased significantly with the increases of fresh-salt water interaction intensity. SOC density was positively correlated with SOC, TN, NH4+-N, and biomass, but negatively correlated with salt ions, soil bulk density, pH, and EC. SOC storage in the 0-30 cm soil layer accounted for 50.9%-64.2% of that in the 0-60 cm soil layer, while SOC storage in the 0-60 cm soil layer occupied 19.1%-37.7% of that in the 0-400 cm soil layer. The results could provide a scientific basis for accurately evaluating SOC storage of estuarine wetlands, improving carbon sink function and wetland management.

Exploring the dynamics of antibiotic resistome on plastic debris traveling from the river to the sea along a representative estuary based on field sequential transfer incubations.

The environmental risks arising from ubiquitous microplastics or plastic debris (PD) acting as carriers of antibiotic resistance genes (ARGs) have attracted widespread attention. Enormous amounts of plastic waste are transported by rivers and traverse estuaries into the sea every year. However, changes in the antibiotic resistome within the plastisphere (the biofilms formed on PD) as PD travels through estuaries are largely unknown. In this study, we performed sequential migration incubations for PD along Haihe Estuary to simulate the natural process of PD floating from rivers to the ocean. Metagenomic sequencing and analysis techniques were used to track microbial communities and antibiotic resistome on migrating PD and in seawater representing the marine environment. The total relative gene copies of ARGs on traveling PD remained stable. As migration between greatly varied waters, additional ARG subtypes were recruited to the plastisphere. Above 80 % ARG subtypes identified in the plastisphere were persistent throughout the migration, and over 30 % of these persistent ARGs were undetected in seawater. The bacterial hosts composition of ARGs on PD progressively altered as transported downstream. Human pathogenic bacteria carrying ARGs (HPBs-ARG) exhibited decreasing trends in abundance and species number during transfer. Individual HPBs-ARG persisted on transferred PD and were absent in seawater samples, comprising Enterobacter cloacae, Klebsiella pneumoniae, Mycobacterium tuberculosis, and Vibrio parahaemolyticus. Based on all detected ARGs and HPBs-ARG, the Projection Pursuit model was applied to synthetically evaluate the potential risks of antibiotic resistance on migrating PD. Diminished risks on PD were observed upon the river-to-sea journey but consistently remained significantly higher than in seawater. The potential risks posed to marine environments by drifting PD as dispersal vectors for antibiotic resistance deserve greater attention. Our results provide initial insights into the dynamics or stability of antibiotic resistome on PD crossing distinct aquatic systems in field estuaries.

Navigating University Openness in Research Policy Inconsistent with Indigenous Data Sovereignty: A Case Analysis.

Indigenous nations and communities in the United States have rights as sovereign governments to exercise control and ownership over all data and information generated by or from the tribes, tribal members, or tribal resources. Indigenous nations exercise these rights through data ownership policies established in response to unethical research practices in research involving Indigenous communities. Most universities in the U.S. have "openness in research" policies to ensure academic freedom to publish freely, exercised by retaining university control of data. Here, we describe our study of cultural ecosystem services in the St. Louis River estuary region (Nagaajiwanaang in the language Ojibwemowin) in Duluth, Minnesota, and Superior, Wisconsin, U.S., an area that includes portions of the 1854 and 1842 Ceded Territories and reservation lands of a local band of Ojibwe (hereafter referred to as "the Band"). In this university-led, Band-supported study, both the university and the Band sought ownership of data collected based on their respective policies, resulting in a research delay of nearly a year. We found that open research policies that do not consider Indigenous sovereignty can hamper collaboration between university researchers and tribal nations, even when there is broad agreement on research goals and objectives. University open research policies that do not explicitly address Indigenous sovereignty fall short of the open research principles they intend to support and should be revised. Formal adoption of principles for ethical research with sovereign tribal governments by universities is needed to improve coordination and trust among university and tribal researchers and members.

Cold-water coral energy reserves and calcification in contrasting fjord environments.

The relationship between energy reserves of cold-water corals (CWCs) and their physiological performance remains largely unknown. In addition, it is poorly understood how the energy allocation to different metabolic processes might change with projected decreasing food supply to the deep sea in the future. This study explores the temporal and spatial variations of total energy reserves (proteins, carbohydrates and lipids) of the CWC Desmophyllum dianthus and their correlation with its calcification rate. We took advantage of distinct horizontal and vertical physico-chemical gradients in Comau Fjord (Chile) and examined the changes in energy reserves over one year in an in situ reciprocal transplantation experiment (20 m vs. 300 m and fjord head vs. mouth). Total energy reserves correlated positively with calcification rates. The fast-growing deep corals had higher and less variable energy reserves, while the slower-growing shallow corals showed pronounced seasonal changes in energy reserves. Novel deep corals (transplanted from shallow) were able to quickly increase both their calcification rates and energy reserves to similar levels as native deep corals. Our study shows the importance of energy reserves in sustaining CWC growth in spite of aragonite undersaturated conditions (deep corals) in the present, and potentially also future ocean.

Characterization of polychaetes inhabiting estuaries and inner bays by composition analysis of amino acids and lactate enantiomers.

In this study, we investigated the composition of free amino acids and lactate (Lac) in polychaetes in river estuaries and inner bays using chromatographic techniques. Both L-amino acids and D-amino acids (D-asparagine, D-alanine (D-Ala), D-serine, D-aspartic acid, and D-proline (D-Pro)) were detected, indicating that polychaetes contain some D-amino acids. Some polychaete species exhibited notable amino acid levels, such as glycine in Capitellidae sp. and Thelepus sp., D-Pro in Glycera sp., and ß-Ala in Scoletoma nipponica and Scoletoma sp.. High D-Lac levels were detected in Tylorrhynchus osawai and Hediste diadroma, (691 and 797 µmol/100 g-wet, respectively), with the D-form exceeding 98%. T. osawai was dominant in the upper tidal-sensitive zone, wherein other organisms were less abundant because of low salinity (3-8 PSU). Seasonal differences in the concentrations of components in T. osawai were observed, particularly a significant increase in D-Lac in the reproductive period. Notably, the D-Lac concentrations of T. osawai were higher upstream than downstream. Thus, D-Lac might be involved in strategies underlying adaptations to low salinity and reproductive activity. These results suggest that both the D-form of Lac and amino acids may play certain physiological roles in the life of polychaetes.

Biogeographic gradients of picoplankton diversity indicate increasing dominance of prokaryotes in warmer Arctic fjords.

Climate change is opening the Arctic Ocean to increasing human impact and ecosystem changes. Arctic fjords, the region's most productive ecosystems, are sustained by a diverse microbial community at the base of the food web. Here we show that Arctic fjords become more prokaryotic in the picoplankton (0.2-3 µm) with increasing water temperatures. Across 21 fjords, we found that Arctic fjords had proportionally more trophically diverse (autotrophic, mixotrophic, and heterotrophic) picoeukaryotes, while subarctic and temperate fjords had relatively more diverse prokaryotic trophic groups. Modeled oceanographic connectivity between fjords suggested that transport alone would create a smooth gradient in beta diversity largely following the North Atlantic Current and East Greenland Current. Deviations from this suggested that picoeukaryotes had some strong regional patterns in beta diversity that reduced the effect of oceanographic connectivity, while prokaryotes were mainly stopped in their dispersal if strong temperature differences between sites were present. Fjords located in high Arctic regions also generally had very low prokaryotic alpha diversity. Ultimately, warming of Arctic fjords could induce a fundamental shift from more trophic diverse eukaryotic- to prokaryotic-dominated communities, with profound implications for Arctic ecosystem dynamics including their productivity patterns.

Climatic, oceanic, freshwater, and local environmental drivers of New Zealand estuarine macroinvertebrates.

Understanding the responses of organisms to different environmental drivers is critical for improving ecosystem management and conservation. Estuarine ecosystems are under pressure from multiple anthropogenic stressors (e.g. increasing sediment and nutrient loads, pollution, climate change) that are affecting the functions and services these ecosystems provide. Here, we used long-term estuarine benthic invertebrate monitoring data (∼30 year time-series) to evaluate the responses of macrobenthic invertebrate communities and indicator species to climatic, oceanic, freshwater, and local environmental drivers in New Zealand estuaries. We aimed to improve our ability to predict ecosystem change and understand the effects of multiple environment drivers on benthic communities. Our analyses showed that the abundance and richness of macrobenthic fauna and four indicator taxa (bivalves known to have differing tolerances to sediment mud content: Austrovenus stutchburyi, Macomona liliana, Theora lubrica, and Arthritica bifurca) responded to unique combinations of multiple environmental drivers across sites and times. Macrobenthic responses were highly mixed (i.e., positive and negative) and site-dependent. We also show that responses of macrobenthic fauna were lagged and most strongly related to climatic and oceanic drivers. The way the macrobenthos responded has implications for predicting and understanding the ecological consequences of a rapidly changing environment and how we conserve and manage coastal ecosystems.

Back on top: Resuspended by dredging and other environmental disturbances, organochlorine compounds may affect the health of a dolphin population in a tropical estuary, Sepetiba Bay.

Organochlorine compounds (OCs) are persistent organic pollutants linked to damaging the immune and endocrine systems, leading to a greater susceptibility to infectious diseases at high concentrations. Sepetiba Bay, in the Southeastern Brazilian coast, historically presents anthropogenic activities and environmental contamination that could negatively impact resident populations. In this context, this study aimed to investigate the temporal trends in the accumulation of organochlorine compounds over a 12-year database in the Guiana dolphins' (Sotalia guianensis) resident population from Sepetiba Bay, including individuals collected before, during, and after an unusual mortality event triggered by morbillivirus (n = 85). The influence of biological parameters was also evaluated. The OCs concentrations in the blubber ranged from 0.98 to 739 µg/g of ΣPCB; 0.08-130 µg/g of ΣDDT; <0.002-4.56 µg/g of mirex; <0.002-1.84 µg/g of ΣHCH and <0.001-0.16 µg/g of HCB in lipid weight. Increased temporal trends were found for OCs in Guiana dolphins coinciding with periods of large events of dredging in the region. In this way, our findings suggest that the constant high OCs concentrations throughout the years in this Guiana dolphin population are a result of the constant environmental disturbance in the area, such as dredging. These elevated OCs levels, e.g., ΣPCB concentrations found above the known thresholds, may impair the response of the immune system during outbreak periods, which could lead the population to a progressive decline.