The authors’ perspective synthesizes prior ecological studies and discussions from a workshop held in Porto Alegre from March 31 to April 4, 2025. Twenty participants from universities in Brazil, Uruguay and Germany included nine researchers, eight graduate students and three undergraduate students. The group reviewed past monitoring and ecological assessments, aligned them with ongoing projects, and developed research priorities for microbial ecology, long-term observation and international collaboration. The paper is a review and position article rather than a new field study or an evaluation of a completed monitoring programme.

The Brazilian coastal plain encompassing the SA-CSSL covers approximately 37,000 km², nearly 40% of which consists of lakes and lagoons. The region extends from 30°S to 35°S and includes the Patos-Mirim complex, described as the world’s most extensive coastal lagoon system. Its lakes formed within the passive-margin Pelotas Basin after four major marine transgressions between approximately 400,000 and 5,000 years ago. Their age, shape, isolation and degree of connectivity vary, creating a wide environmental gradient for comparative research.

A defining feature is the presence of large freshwater bodies close to the ocean, an uncommon condition on sedimentary coasts where brackish or saline lagoons are prevalent. Freshwater conditions are associated with high precipitation, aquifers beneath the coastal barrier and substantial river input, including the Guaíba system. Strong winds, mainly aligned northeast to southwest, elongated and segmented the lakes. They are polymictic, with wind continually mixing the water column throughout the year and producing a setting in which atmospheric changes can rapidly affect lake conditions.

Human pressures are already substantial across the region. Lakes range from oligotrophic to hypereutrophic because of urban wastewater and agricultural runoff. Extreme climatic events have also been associated with abrupt changes, including reduced water levels, macrophyte proliferation and eutrophication, especially where marine connectivity is restricted or anthropogenic pressure is high. The authors identify four representative subsystems: the Tramandaí River System, Patos Lagoon System, Mangueira-Mirim System and Uruguayan Lagoon System. Together, these units encompass contrasts in climate, land use, connectivity, population pressure and ecological condition.

The Tramandaí system contains about 40 lakes, most with some connection to one another, and supports more than 265,000 residents, 90% in urban areas. Untreated sewage, agricultural runoff, water withdrawal and invasive species are major pressures. The lakes supply drinking water to at least 17 municipalities while also receiving untreated or partly treated sewage. In Imbé, only 0.5% of domestic effluents were reported as collected and treated, while seasonal tourism can increase the population tenfold. The Patos and Mangueira-Mirim systems add estuarine salinity gradients, extensive agriculture and major urban centres to the range of conditions available for monitoring.

Existing studies illustrate the network’s value for environmental surveillance. Microplastics were measured at 225–240 units per 100 m³ in two larger Tramandaí lakes, with PET, PVC, polypropylene and polyethylene among the polymers analysed. The study did not establish that those four polymers dominated total pollution. Microbial communities associated with the “plastisphere” contained taxa of potential public-health concern, particularly in summer. In the Uruguayan lagoons of Rocha and Castillos, high-throughput sequencing and basin-scale chemical profiling showed that bacterioplankton assemblages were partially structured by gradients of pharmaceuticals, pesticides and endocrine disruptors. Seasonal differences in microbial signatures distinguished contamination levels and included xenobiotic degraders, pathogens and opportunistic pathogens.

Other work has examined fish ecology, macrophyte effects on microbial communities, environmental DNA, cyanobacterial blooms and remote sensing of blooms and water-surface temperature. These studies give the region a substantial interdisciplinary foundation, while the network’s underrepresentation in global datasets remains a limitation. For example, more than 98% of the 8,000 lakes used in one carbon-emissions analysis were outside the tropics. The authors argue that adding SA-CSSL observations could help reduce geographic bias in global carbon budgets and projections, although they did not quantify that effect.

Climate projections cited in the review predict a 15% increase in precipitation in southern Brazil between 2011 and 2040 across all considered human carbon-dioxide-emission scenarios, with similar trends projected for later decades. Greater ENSO variability is presented as a predicted development, not an already established trend. The ecological consequences of the May 2024 Rio Grande do Sul floods, which affected 478 of 497 municipalities and 2.4 million people, remain largely unexplored. The authors also propose a monitoring framework organized around planetary boundaries, together with standardized indicators, GIS-based communication tools and citizen-science approaches.

The review’s central proposal is that the SA-CSSL provide a geographically extensive but not yet fully integrated model for studying how subtropical shallow lakes respond to interacting climatic and anthropogenic pressures. Its value lies in the network’s gradients—from freshwater to intermittently brackish systems and from relatively intact grasslands to urban and agricultural catchments. The proposed framework is not itself evidence that these lakes already function as a continental sentinel system; assessing that role will require coordinated, sustained monitoring and clearer evidence linking observations across the four subsystems.

Subject of Research: Monitoring climate and anthropogenic changes in subtropical coastal shallow lakes across southern Brazil and eastern Uruguay

Article Title: Coastal subtropical Southern American shallow lakes as unique ecosystems for monitoring anthropogenic induced ecosystem changes

Article References: Kluge, M., Shubeita, A., Uchaikina, A., Alonso, C., Herrman, B., Menegotto-Silva, C., Lopes, C., Pagani, D., Marques, D., Moreira-Silva, E., Kristiansson, E., Quintana, I., Cavalcanti, J., Fleck, J., Ribeiro, K., Varghaei, L., Oliveira, L., Rodrigues, L., Ramilo, L., … Medina-Silva, R. (2026). Coastal subtropical Southern American shallow lakes as unique ecosystems for monitoring anthropogenic induced ecosystem changes. One Ecosystem, 11, Article e186107. https://doi.org/10.3897/oneeco.11.e186107

Image Credits: AI Generated

DOI: 10.3897/oneeco.11.e186107

Keywords: shallow lakes, coastal lagoons, Southern Brazil, Uruguay, global change, eutrophication, microbial ecology, ENSO, land-use change, long-term monitoring, Coastal, subtropical

The Ciénaga Grande de Santa Marta, located in the Department of Magdalena, forms the Estuarine Delta System of the Magdalena River and extends to the Caribbean Sea. Its ecosystem assets include the largest mangroves in the Colombian Caribbean, continental wet areas, coastal lagoons, forests, agricultural and transformed land types. The site supports fisheries and agriculture and provides carbon storage, habitat and other services to local communities. It also carries a series of overlapping conservation designations, including a flora and fauna sanctuary, a biosphere reserve, an important bird area, the Salamanca Island Park and Ramsar status. The Ramsar designation dates to 1998.

The wetland’s condition depends on the interaction between freshwater and seawater throughout the year. This exchange shapes water salinity, while changes in river flow alter the salinity of mangrove soils and influence both vegetation and fisheries. Diversion of water from rivers descending from the Sierra Nevada de Santa Marta for agriculture, together with construction of the Barranquilla–Ciénaga and Palermo–Sitio Nuevo roads, has altered exchange inlets and reduced connectivity between the Magdalena River and the lagoon complex. An integral environmental recovery program initiated by INVEMAR in the 1990s included dredging a five-channel network to restore water exchanges among the Magdalena River, lagoon bodies and the Caribbean Sea. Monitoring of the resulting hydrological regime continues, with hydro-sedimentological observation beginning in 2017.

These pressures complicate an ecosystem already affected by climatic variability. Strong and very strong El Niño events in 2015 and 2016 were associated in the study with reduced rainfall in the Colombian Caribbean, increased mangrove-soil salinity and hydrological stress. In 2017, a Ramsar advisory mission found strong changes in the wetland’s ecological characteristics associated with water-balance loss and human intervention, leading to its inclusion in the Montreux Record. The new study combined environmental and socioeconomic data into a spatial account intended to show how changes in ecosystem extent and condition affect the supply of services and the associated economic value.

For the extent account, researchers compared two CORINE Land Cover layers mapped at a scale of 1:100,000, representing 2012 and 2018. They standardized the land-cover classifications, calculated geodesic areas and used spatial intersections to construct a transition matrix showing opening extent, gains, losses and closing extent. Pastures, continental wet areas and mangrove forests recorded the largest losses during 2012–2018, while permanent crops, heterogeneous agricultural areas and areas with herbaceous or shrub vegetation recorded the largest gains. Mangroves, continental wet areas and pastures mainly transitioned into agricultural or transformed-cover classes. The analysis identified where losses occurred but could not attribute each gain or loss to a specific natural event or human action.

Condition accounts were possible only for mangroves and coastal lagoons and covered 2017–2019 because of data availability. The framework classified condition variables under abiotic, biotic and landscape characteristics. Mangrove indicators included basal area, seedling and propagule density, interstitial salinity, bird species richness and change in extent related to water. Coastal-lagoon indicators included dissolved oxygen, total suspended solids, surface salinity and fish species richness. Reference levels drawn from monitoring reports, regulatory criteria, bibliographic sources and observed salinity ranges were used to rescale variables and construct aggregate condition indices.

The two monitored ecosystem types showed different trends. Mangrove condition had a net positive change from 2017 to 2019 because abiotic values rose as interstitial salinity declined, biotic values rose with greater bird richness and more seedlings and propagules, and landscape values improved as mangrove area expanded. Basal area decreased during the period, showing that recovery was not uniform across every measured characteristic. Coastal lagoons recorded a net negative change: dissolved oxygen declined, surface salinity increased and fish species richness fell. The contrasting aggregates demonstrate how condition accounting can distinguish environmental improvement in mangrove forests from deterioration in adjacent lagoon waters.

Mangrove extent increased by 3,503 hectares during 2017–2019, equivalent to a reported recovery of 6.87% relative to the 51,150 hectares recorded in 1956. The researchers associated this increase with freshwater inflows through dredged channels connected to the Magdalena River and with the absence of El Niño-related events during part of the accounting period. Bird richness also increased, with 98 species recorded in 2019. The list included the northern screamer, sapphire-bellied hummingbird and bronzed cowbird, together with numerous migratory species. These observations describe improvement within the selected indicators and period; they do not establish that every component of the lagoon complex recovered.

Fishing-resource data showed how environmental variation appeared in a service used by communities. SIPEIN records showed total artisanal catch ranging from 4,617 to 6,035 tonnes per year between 2015 and 2019, a net difference of 721 tonnes per year between the opening and closing years. Fish contributed the largest catches, followed by crustaceans. Mollusc catches were not collected in 2018–2019 because of logistical problems, so the reported total underestimates those resources in those years. Catch fell sharply in 2016, coinciding with the highest salinity records in two decades, and subsequently recovered as salinity declined and the composition of the fishery shifted among estuarine, marine and freshwater species. The account therefore documents an association between salinity, climate variability and recorded catches rather than isolating the contribution of any one factor.

The climate-regulation account focused on mangrove carbon. Aboveground carbon was estimated from tree diameter and biomass relationships, while belowground estimates were drawn from measurements covering the upper metre of soil. Carbon stocks were valued using Colombia’s carbon tax rate, set at USD 5 per tonne of carbon dioxide in 2017 with annual adjustment. Aboveground carbon content declined across the principal mangrove types over 2015–2019, leaving total mangrove carbon 16.5% lower in 2019 than in 2015. Most of the decline occurred between 2015 and 2017, when mangrove loss, hydrological stress, desiccation and charcoal burning were associated with carbon emissions rather than sequestration. Physical carbon stocks rose during 2018 and 2019, but their monetary value declined as the Colombian peso depreciated against the dollar. Soil-carbon estimates are incomplete because the reference measurements covered only one metre, while mangrove carbon reservoirs extend deeper.

The monetary asset account placed the value of mangrove carbon stocks at USD 68.3 million in 2015 and USD 55.13 million in 2019. Annual wild-fish supplies from mangroves and coastal lagoons were converted to asset values using a net-present-value method with a 100-year asset life and a 3.5% social discount rate. The combined mangrove and coastal-lagoon asset estimate was USD 105.71 million in 2015 and USD 97.27 million in 2019. The resulting difference of USD 21.61 million comprised USD 13.17 million in mangrove losses and USD 8.44 million in losses for the combined coastal-lagoon and mangrove category. These are accounting estimates, not observed losses of cash or conventional market assets. They provide a way to place ecosystem assets and service flows on the same statistical framework as economic activity.

The pilot also exposes important constraints. Catch is recorded at four landing places and distributed across the wetland, rather than assigned to the specific mangroves, lagoons or marine areas that produce it. This prevents precise attribution of fishing benefits within an interconnected coastal landscape. The condition accounts do not include all six classes in the SEEA EA condition typology, and the land-cover transition analysis cannot determine whether individual changes resulted from El Niño, farming, infrastructure or another pressure. Fishers’ income also cannot be inferred from physical catch alone because market prices, price elasticity, consumer preferences and pre-sales arrangements affect the revenue received. Even with those limitations, the account establishes a baseline for monitoring the extent, condition and service flows of a Ramsar wetland and offers Colombia a spatial framework for integrating ecosystem information into environmental statistics, biodiversity reporting and economic planning.

Subject of Research: Pilot ecosystem accounting of Colombia’s Ciénaga Grande de Santa Marta Ramsar Site

Article Title: Accounting of marine and coastal ecosystems at the Ramsar Site, Estuarine Delta System of the Magdalena River, Ciénaga Grande de Santa Marta, Colombia

Article References: Gomez Cardona, C., Moreno, J., Contreras, A., Sanchez-Nuñez, D., Arciniegas Moreno, N., Guerrero, D., Viloria Maestre, E., & Lopez Navarro, J. (2023). Accounting of marine and coastal ecosystems at the Ramsar Site, Estuarine Delta System of the Magdalena River, Ciénaga Grande de Santa Marta, Colombia. One Ecosystem, 8, Article e98852. https://doi.org/10.3897/oneeco.8.e98852

Image Credits: AI Generated

DOI: 10.3897/oneeco.8.e98852

Keywords: Ciénaga Grande de Santa Marta, ecosystem accounting, SEEA EA, mangrove carbon, coastal lagoons, artisanal fisheries, wetland condition, natural capital, El Niño, Ramsar Site, Accounting, marine

Coastal lagoons are saline or brackish shallow basins oriented parallel to the shoreline, cut off from the open ocean by sandy barriers, shoals, reefs or chains of islands, with only restricted or ephemeral connections to the sea through tidal channels. Because these channels may open and close naturally or through human intervention, lagoons can range from nearly fresh to hypersaline. They are true ecotones, transitional zones where terrestrial and marine systems intermingle, and their multiple boundaries — with the sea, the land, the atmosphere, sediments and freshwater inflows — generate steep physicochemical gradients that fuel extraordinary biological productivity. Annual primary production in these systems ranges from 50 to more than 500 grams of carbon per square meter per year, placing them on par with the ocean’s great upwelling regions. Because most lagoons are shallow enough for sunlight to reach the seabed, and because winds constantly resuspend nutrient-rich sediments, benthic algae and seagrasses can outproduce even the phytoplankton in the water column.

That productivity underwrites an impressive portfolio of ecosystem services. Lagoons serve as spawning grounds and nurseries for commercially valuable fish, sequester carbon, cycle nutrients, purify water, buffer local climates and support tourism, transport and food provision for densely populated coastal communities. But the same proximity to cities makes them vulnerable. Nearly half of the world’s coastal wetlands have been lost or degraded over the past century through the combined pressures of local human activity and climate change, and Brazilian lagoons face warming trends documented across every one of the country’s marine ecoregions, alongside projected sea-level rise of up to 0.98 meters by 2100. Within these systems, macroalgae occupy a pivotal position: they anchor food webs, drive nutrient cycling and respond rapidly to changes in depth, turbidity, light and nutrient levels, which is why they are widely used worldwide as bioindicators of pollution and ecological degradation.

To establish how much is actually known about Brazilian lagoon macroalgae, the research team first turned to satellite imagery. Using Google Earth at scales of 200 to 1,000 meters, they inspected the entire coastline, georeferencing every water body that met the classical definition of a coastal lagoon and applying a cutoff distance of 5.5 kilometers from the maritime shoreline to exclude inland lakes. The census identified 300 lagoons, distributed unevenly across all five of Brazil’s marine ecoregions. The Rio Grande ecoregion in the far south dominated the tally with 124 lagoons — 41.3 percent of the total — followed by the Northeast with 25.7 percent and the Southeast with 17 percent. Of Brazil’s 17 coastal states, only three — Amapá, Pará and Piauí — lacked typical lagoons, while Rio Grande do Sul alone accounted for 29 percent of them, with Santa Catarina, Rio de Janeiro and Bahia close behind.

The literature search was equally exhaustive. The team queried five databases — SciELO, Web of Science, Scopus, Google Scholar and the CAPES Periódicos portal — in English and Portuguese, using the keywords alga, seaweed, lagoon and Brazil in various combinations. More than 20,000 initial documents surfaced, but after rigorous screening under PRISMA guidelines only 13 peer-reviewed articles survived the filters. Snowballing through their bibliographies, searches of theses and dissertations, and a sweep of the publication records of all 62 authors involved eventually expanded the corpus to 48 studies. Even so, those 48 papers covered just 11 lagoons, and the effort was heavily skewed: 17 documents concerned the Patos Lagoon in Rio Grande do Sul, while 22 addressed seven different lagoons in Rio de Janeiro state. Only four states — Alagoas, Rio de Janeiro, Santa Catarina and Rio Grande do Sul — have any lagoon macroalgae research at all. Notably, the number of studies correlated strongly with lagoon size, with a Pearson correlation coefficient of 0.92, and with the proximity of research institutions, suggesting science follows convenience as much as ecological importance.

The catalogued flora comprised 213 macroalgal taxa, dominated by red algae (Rhodophyta, 56 percent of taxa), followed by green algae (Chlorophyta, 32.4 percent) and ochrophytes (11.7 percent). The richest site was the hypersaline Araruama Lagoon in Rio de Janeiro, with 119 taxa, followed by Itaipú with 72, Patos with 60 and Conceição with 56. The most frequently recorded genera were the green opportunists Ulva, Chaetomorpha and Cladophora, along with the red algae Bryocladia subtilissima and Gymnogongrus griffithsiae. Yet when the researchers compared assemblages across lagoons using Bray-Curtis similarity coefficients on presence-absence data, no two lagoons grouped above 50 percent similarity. Even at a lenient 20 percent cutoff, the Mundaú and Açú lagoons stood entirely alone. This striking dissimilarity presents the study’s central unresolved question: are Brazil’s lagoons genuinely unique, each harboring a distinct flora with high beta diversity, or are they simply understudied, their true floras unknown?

Several ecological patterns did emerge from the fragmented record. Algal richness and abundance generally decline from lagoon entrances toward their inner reaches, mirroring patterns described in bays and estuaries and likely driven by salinity — a key determinant of macroalgal distribution — along with substrate, light, nutrients and turbulence. Opportunistic green algae dominate the inner, low-salinity zones, while red algae and ochrophytes retreat toward the sea connections. Araruama Lagoon is a fascinating exception: despite salinity increasing toward its interior, reaching values of up to 80 in the world’s largest permanent hypersaline lagoon ecosystem, its stable extreme conditions support comparatively high richness. Even there, however, decades of shell extraction for soda ash production removed nearly half of the hard substrate algae need, and richness has fallen by roughly a third over 26 years as urbanization and tourism increased nutrient inputs and reduced water transparency.

The review also exposed how geography and history shape the science. The Patos Lagoon, the largest choked-type lagoon in the world and South America’s biggest at 10,227 square kilometers, hosts the longest-running research program thanks to the Brazilian Long-Term Ecological Research initiative (PELD), which has monitored its estuary continuously since 1998. It is the only Brazilian lagoon where isotope studies of macroalgae have been conducted, and the site of the country’s first macroalgal bioindicator study in 1982. By contrast, the Amazonian ecoregion contains a single lagoon — Jansen, in Maranhão, artificially maintained by a sluice gate against one of the world’s largest tidal ranges — with no macroalgae studies whatsoever. In the Northeast, strong sediment drift frequently seals lagoon entrances, leaving little hard substrate for algal attachment and murky waters that may explain both fewer algae and fewer phycologists.

The authors are candid about the limitations of their synthesis. Old identifications could not be re-examined, so taxonomically complex groups such as the morphologically plastic Ulva may inflate richness estimates; some historical references, including the only record of the Açú Lagoon flora — found in conference proceedings purchased from a used bookstore — could not be obtained at all, and inconsistent terminology for lagoons across languages and legal frameworks may have hidden relevant studies from the search. Still, the message is unambiguous. Macroalgae are cost-effective, sensitive and well-established ecological indicators, and Brazil’s management frameworks, including the ReBentos network and emerging Marine Spatial Planning, could integrate them immediately. The researchers call for targeted surveys, standardized comparative methods, digitization of historical collections and expansion of long-term monitoring to unstudied lagoons. Without baselines, they warn, conservation planning, pollution control and protected-area design for these 300 ecosystems will proceed blind — and whether each lagoon is a botanical treasure or a terra incognita may never be known before it changes forever.

Subject of Research: Distribution of coastal lagoons and the diversity and monitoring potential of their macroalgal flora in Brazil

Article Title: Macroalgae in coastal lagoons: a systematic review from Brazil

Article References: Amaral, H. B. F., Copertino, M., & Creed, J. C. (2026). Macroalgae in coastal lagoons: a systematic review from Brazil. Estuarine Management and Technologies, 3, 87-112. https://doi.org/10.3897/emt.3.186569

Image Credits: AI Generated

DOI: 10.3897/emt.3.186569

Keywords: coastal lagoons, macroalgae, Brazil, systematic review, bioindicators, biodiversity, eutrophication, Rhodophyta, Patos Lagoon, Araruama Lagoon, ecosystem services, marine ecoregions

A team of researchers working within European research infrastructure projects has published a harmonized, individual-level dataset of phytoplankton traits collected from fourteen transitional water sites across the Mediterranean and Black Sea regions. Spanning Albania, Bulgaria, Greece, Italy, and Romania, the dataset contains 104,687 individual records covering 242 accepted taxa distributed across ten phyla, twenty-two classes, sixty-seven orders, one hundred families, and one hundred thirty-six genera. Crucially, the data were collected not just at the species level, as most trait databases are, but cell by cell, capturing the fine-grained variation within populations that ecologists increasingly recognize as essential for understanding how communities respond to environmental change.

Transitional waters, the dynamic ecosystems perched at the boundary between rivers and seas, are among the most variable and vulnerable habitats on Earth. Their salinity, nutrient loads, and hydrology fluctuate dramatically with freshwater inputs, tidal exchange, climatic variability, and human activity. The lagoons in this study, from Alimini and Torre Guaceto in southern Italy to Varna Bay in Bulgaria and Sinoe lagoon in Romania, are microtidal or non-tidal, nutrient-rich, depositional systems that experience intense anthropogenic pressure while simultaneously hosting remarkable biodiversity. Understanding how phytoplankton communities organize themselves across such steep environmental gradients is a central question in functional ecology, and it requires data of a kind that has been notoriously difficult to find.

The original sampling took place during two coordinated campaigns, in October 2004 and April 2005, conducted under the INTERREG IIIB CADSES TWReference Net Project coordinated by Prof. Alberto Basset and funded by the European Union’s Seventh Framework Programme. At each lagoon, between one and seven sampling stations were established according to a hierarchical design meant to capture both seasonal and spatial variability. Researchers collected water from a depth of half a meter using a Ruttner bottle, preserved samples in Lugol’s iodine solution, and stored them in darkness at four degrees Celsius until analysis. Physicochemical conditions, including temperature, salinity, pH, and dissolved oxygen, were measured in situ with a multiparametric probe, while nutrient samples were processed immediately upon arrival at the laboratory using standard methods.

The laboratory work is where the dataset acquires its unusual power. Following the classical Utermöhl method, subsamples were examined under an inverted Nikon T300E microscope at four hundred times magnification. For each sample, a minimum of four hundred cells were counted, measured, and identified to the lowest possible taxonomic level, ensuring statistically robust estimates of both community composition and cell dimensions. Each cell was assigned to one of twenty-four geometric shapes, from simple spheres and cubes to composite forms such as a cone paired with a half sphere, and its linear dimensions were recorded. These measurements fed into geometric equations that calculate biovolume, which was then converted into individual carbon content using the widely cited equations of Menden-Deuer and Lessard, and into biomass using a conversion factor of 1.03.

The resulting picture of phytoplankton life in these lagoons is strikingly region-dependent. By density, Chlorophyta, the green algae, dominated the dataset at 37.39 percent of total abundance, followed by Cyanobacteria at 23.58 percent and Cryptista at 15.12 percent. But biomass tells a very different story: Dinoflagellata contributed the largest share at 36.29 percent, followed by Heterokontophyta, the group containing diatoms, at 20.08 percent. This discrepancy reflects a fundamental ecological truth, that large-celled groups such as dinoflagellates and diatoms punch far above their numerical weight when it comes to carbon and energy flowing through the food web. Counting cells alone would badly misrepresent the functional structure of these communities.

Geographic contrasts were equally revealing. Mediterranean lagoons hosted communities with richness values typically between twenty-three and forty-nine taxa, whereas Black Sea lagoons were richer, ranging from forty-six to seventy-nine taxa, with the highest diversity observed in Varna. Mediterranean communities were more evenly distributed, with alternating dominance of Cryptista, Cyanobacteria, and Chlorophyta in density terms, while Black Sea systems, particularly Sinoe and Varna, showed stronger dominance by cyanobacteria and dinoflagellates, especially when biomass was considered. Shannon diversity values based on density ranged from 0.56 to 2.56 across lagoons, indicating substantial differences in community evenness from one system to the next.

Even cell shape itself carries an ecological signal. Across the whole dataset, cube-shaped cells accounted for 19.3 percent of total density and cylindrical cells 19.2 percent, together making up nearly forty percent of all individuals counted. Shape composition differed sharply between the two seas: the cone-plus-half-sphere morphology dominated Mediterranean sites at 43.8 percent of cell density, while cylindrical forms, associated with genera such as Cyclotella, Anabaena, and Planktolyngbya, and cube-shaped cells, represented mainly by Merismopedia and Crucigenia, predominated in the Black Sea. Grouped by geometric complexity, simple shapes accounted for roughly seventy-two percent of total density overall, but the balance shifted between regions, with simple shapes reaching 78.0 percent of mean relative density in Black Sea sites compared with a more even 50.8 percent split in the Mediterranean.

What elevates this dataset beyond a simple archive is the extraordinary effort devoted to making the data genuinely interoperable and reusable, compliant with the FAIR principles of findability, accessibility, interoperability, and reusability. The phytoplankton records are accompanied by a complementary abiotic dataset containing in situ measurements of salinity, conductivity, temperature, pH, dissolved oxygen, oxygen saturation, and total dissolved solids, along with nutrient concentrations including nitrite, nitrate, ammonium, dissolved inorganic nitrogen, phosphate, and silicate. Physiographic and hydrological characteristics of each lagoon, such as water depth, tidal range, inlet morphology, sinuosity index, surface area, and hydrological connectivity, are included alongside qualitative descriptors of anthropogenic pressure and protection status, including Ramsar designation, Natura 2000 site membership, and local protection plans.

The curation pipeline drew on an impressive array of controlled vocabularies and standards. Data were organized using the Data Template Builder tool of the Phytoplankton Virtual Research Environment, incorporating concepts from Darwin Core standards, the Traits Thesaurus, MarineRegions, EnvThes, and NERC vocabularies to generate semantically consistent data tables. Taxonomic validation was performed against the AlgaeBase repository, with both the original identification and the accepted name preserved in the dataset through dedicated Darwin Core properties, ensuring traceability. Morphological shape assignments were verified using the Atlas of Shapes web service, and trait computation was automated through a dedicated Python-based e-service. The dataset has already served as a reference case for harmonization and trait-based integration within the Phyto VRE and has underpinned previously published studies on morpho-functional analysis, guild classification, and hypothesis testing across multiple levels of biological organization.

Archived in comma-separated value format with metadata in the Ecological Metadata Language 2.2.0 standard, the two datasets are openly accessible through the LifeWatch Italy Data Portal and Metadata Catalogue under a Creative Commons Attribution 4.0 licence. For researchers studying functional diversity, trait-environment relationships, or the ecology of coastal ecosystems under mounting human pressure, the resource represents something rare: a standardized, cell-level record spanning five countries, two seas, and a full spectrum of environmental gradients. As transitional waters face intensifying eutrophication, hydrological alteration, and climate-driven change, having a decade-spanning, taxonomically validated, individually measured baseline from these vulnerable lagoons may prove invaluable, not only for charting what has been lost, but for predicting what these ecosystems, and the microscopic engines at their heart, will become.

Subject of Research: Individual-level phytoplankton trait data from Mediterranean and Black Sea transitional waters

Article Title: A harmonized individual-level phytoplankton trait dataset from Mediterranean and Black Sea transitional waters

Article References: Titocci, J., Laraib, M., Semeraro, T., & Basset, A. (2026). A harmonized individual-level phytoplankton trait dataset from Mediterranean and Black Sea transitional waters. Biodiversity Data Journal, 14, Article e196603. https://doi.org/10.3897/bdj.14.e196603

Image Credits: AI Generated

DOI: 10.3897/BDJ.14.e196603

Keywords: phytoplankton, trait-based ecology, transitional waters, coastal lagoons, Mediterranean Sea, Black Sea, FAIR data, biovolume, functional diversity, biodiversity data, cyanobacteria, dinoflagellates

The study, led by Riley Barton of the Marine and Coastal Research Laboratory at Pacific Northwest National Laboratory and Rensselaer Polytechnic Institute, together with Sasha Wagner, Christina M. Richardson, Alex Collins, Margaret A. Zimmer, Maya Montalvo, and Allison N. Myers-Pigg, focused on five small coastal mountain watersheds in California that were burned by the CZU Lightning Complex Fires of 2020. That fire event, ignited by an extraordinary lightning storm, tore through the Santa Cruz Mountains and left steep coastal drainages draped in ash and charred vegetation. Because these watersheds drain directly toward the Pacific, they offered an ideal natural laboratory for tracking how fire-altered carbon moves from land to sea.

The researchers zeroed in on a molecule called levoglucosan, an anhydrosugar that forms when cellulose and hemicellulose, the structural carbohydrates of plant tissue, are burned at moderate temperatures. Levoglucosan has long served as a molecular fingerprint for biomass burning in atmospheric science, because it is produced in abundance during combustion and can travel long distances in smoke. But in aquatic systems, levoglucosan has a very different personality: it is highly soluble, which means it dissolves readily in the first rains after a fire, and it is biolabile, meaning microbes can consume it quickly as a carbon and energy source. In other words, levoglucosan is the ephemeral, fast-cycling counterpart to the stubborn, centuries-persistent black carbon that has dominated discussions of fire-derived carbon in rivers.

Black carbon, by contrast, is the charred, condensed aromatic material that gives burned soils their dark color. It is famously recalcitrant, resisting microbial decay and persisting in soils, sediments, and the open ocean for hundreds to thousands of years. Because of this stability, black carbon has been treated as the primary long-term sink in the fire-carbon equation, and much of the aquatic research on pyrogenic carbon, often abbreviated PyC, has centered on quantifying these durable fractions. The new study asked a deceptively simple question: if you measure both the labile and the recalcitrant fire-derived carbon in the same streams at the same time, do they behave the same way?

The answer, emphatically, is no. Levoglucosan concentrations in the streams peaked during the earliest post-fire flows, the very first storm-driven runoff events after the flames were out, and then declined steadily over time. Remarkably, this decline was independent of stream discharge. It did not matter how much water was coursing through the channels; the levoglucosan signal faded because the supply was being exhausted, flushed out of the burned landscape during those initial pulses and consumed by microbes along the way. Black carbon told the opposite story. Its concentrations were discharge-driven, rising when flows rose, and, counterintuitively, they increased with time since the fire. The researchers attribute this delayed pattern to gradual solubilization: the charred material left on the landscape does not dissolve immediately but slowly becomes available to water over months and years as physical and chemical weathering break it down.

This divergence matters because it means that the two major categories of pyrogenic carbon operate on fundamentally different clocks. Labile anhydrosugars are a flash flood of bioavailable carbon, delivered within the first post-fire storm seasons and efficiently transported all the way to coastal lagoons and nearshore zones. Black carbon is a slow-release reservoir, accumulating in export pathways over longer timescales. A monitoring program that samples a burned watershed a year or two after a fire, or one that focuses only on the recalcitrant fraction, would completely miss the early, intense pulse of labile carbon, and with it, a significant chapter in the post-fire carbon budget.

The downstream consequences could be substantial. When levoglucosan and other soluble, easily degraded combustion products arrive in coastal lagoons and nearshore waters, they provide a fresh fuel source for microbial communities. Enhanced microbial processing means enhanced remineralization, the conversion of organic carbon back into carbon dioxide, potentially altering the carbon balance of these transitional ecosystems and influencing oxygen demand, nutrient cycling, and food web dynamics. Coastal lagoons along the California coast are already sensitive environments, subject to seasonal sandbar closure, variable salinity, and increasing fire pressure in their upstream catchments. A sudden influx of labile pyrogenic carbon could ripple through these systems in ways that measurements of black carbon alone would never reveal.

The broader implication is that wildfire’s impact on the global carbon cycle may be underestimated. Wildfire frequency and severity are increasing across the western United States and many other regions of the world, and each fire leaves behind a spectrum of organic matter ranging from the environmentally persistent to the rapidly degradable. If carbon accounting and biogeochemical models focus on the recalcitrant end of that spectrum, they will capture the long-term storage story but miss the fast-cycling one. The authors argue that expanding the focus beyond recalcitrant pyrogenic carbon to include labile compounds is essential to capture the full impact of terrestrial fires on carbon dynamics across the land-ocean aquatic continuum, the connected chain of rivers, lakes, estuaries, and coastal waters through which carbon travels from continents to the sea.

Methodologically, the study demonstrates the value of pairing molecular tracers with hydrologic context. By measuring levoglucosan and black carbon side by side across multiple burned watersheds and multiple flow conditions, the team could disentangle the effects of supply exhaustion from the effects of dilution and transport. The independence of the levoglucosan decline from discharge is a particularly telling signature: it points to a finite, depletable pool of soluble combustion products rather than a continuous source regulated by water flux. Such distinctions are exactly what models of post-fire carbon export need in order to predict how landscapes will behave as fire regimes intensify.

The research, supported by the National Science Foundation and the U.S. Department of Energy’s Office of Science, and conducted as part of Barton’s doctoral dissertation, arrives at a moment when fire science is racing to keep pace with a changing fire regime. As more watersheds burn and more rain falls on fresh ash, the first flush of labile carbon into rivers and coasts may prove to be one of the most dynamic and underappreciated consequences of wildfire. Recognizing that not all fire-derived carbon behaves alike, and that the most fragile molecules may carry the biggest early signal, is a crucial step toward understanding what burning landscapes mean for the carbon cycle from mountaintop to ocean.

Subject of Research: Post-fire mobilization of levoglucosan and black carbon in coastal California watersheds

Article Title: Early post-fire mobilization of levoglucosan distinctly contrasts black carbon dynamics in small coastal mountain watersheds

Article References: Barton, R., Wagner, S., Richardson, C. M., Collins, A., Zimmer, M. A., Montalvo, M., & Myers-Pigg, A. N. (2026). Early post-fire mobilization of levoglucosan distinctly contrasts black carbon dynamics in small coastal mountain watersheds. Biogeochemistry. https://doi.org/10.1007/s10533-026-01367-3

Image Credits: AI Generated

DOI: 10.1007/s10533-026-01367-3

Keywords: levoglucosan, black carbon, pyrogenic carbon, wildfire, watersheds, biogeochemistry, carbon cycle, anhydrosugar, coastal lagoons, organic carbon, CZU Lightning Complex Fire, carbon export

The work focuses on two Annex I habitat groups: inland peat-forming wetlands (Group 7: “Raised bogs, mires and fens”) and coastal lagoons (habitat type 1150). By translating complex ecology into actionable monitoring concepts, the report is designed to inform condition assessments under the Habitats Directive, the Water Framework Directive, and the Nature Restoration Regulation.

Europe’s wetland story, however, is one of dramatic contraction. An estimated 80% of wetland area present a century ago no longer exists, and more than half of remaining peatlands have been drained. Despite their limited geographic footprint, peatlands store nearly one-third of global soil carbon, while coastal lagoons—covering roughly 13% of the global coastline—support disproportionately high biodiversity and biological productivity.

At the center of the report is a unifying conclusion: hydrology is the principal determinant of ecosystem condition. In peatlands, persistently high and stable water tables maintain anoxic conditions that suppress decomposition, enabling peat to accumulate. When drainage lowers the water table, peat oxidizes, subsides, and compacts, vegetation and microbial communities shift, and wildfire risk rises.

Crucially, structural changes to peat can be effectively irreversible. What begins as hydrological disruption can also flip a long-term carbon sink into a net source of greenhouse gases. Coastal lagoons face a different hydrological challenge: freshwater–marine exchange. There, circulation patterns, sediment transport, nutrient availability, and physico-chemical gradients shape community structure and productivity—often with strong natural variability unrelated to direct human pressure.

The report also emphasizes that degradation rarely comes from a single culprit. Drainage, land-use conversion, nutrient enrichment, peat extraction, contaminant inputs, coastal development, and climate change interact in reinforcing, sometimes non-linear ways. This pressure stacking can make ecological decline difficult to detect, attribute, and reverse.

To improve monitoring, the authors argue that no single indicator can capture ecosystem health. Instead, they propose tiered indicator frameworks separating essential from complementary variables across hydrological, physico-chemical, biological, and functional dimensions. Natural spatial and temporal variability—and ecological succession—must be explicitly accounted for, or monitoring may confuse intrinsic dynamics with human impact.

The report further calls for integrating Earth Observation with in-situ measurements. Remote sensing is best suited for hydrology and vegetation-linked metrics, but it must be field-calibrated and validated to maintain scientific reliability. Finally, it outlines a transition toward an integrated observation architecture combining Earth Observation, ground data, numerical modelling, and digital twin approaches.

This roadmap includes a dual monitoring strategy: standardized routine surveillance to capture heterogeneity and adaptive event-based monitoring for extremes and unexpected impacts. The authors frame the approach as a scientific foundation for a future EU Wetland Watch service, while identifying the next critical step—habitat-specific condition thresholds calibrated across Member States.

Subject of Research: Ecological characterisation of European peatlands and coastal lagoons for EU wetland assessment, monitoring, and restoration.
Article Title: Ecological characterisation of peatlands and coastal lagoons in Europe
News Publication Date: 2026
Web References: https://publications.jrc.ec.europa.eu/repository/handle/JRC146927
References: Cetinic, K.A., Pérez-Ruzafa, Á., Boix, D., Cravo-Laureau, C., Klimkowska, A., et al, Ecological characterisation of peatlands and coastal lagoons in Europe, Blasi, M., Korcheva, A., Vasilakopoulos, P. and Velasco Gomez, D.M. (editors), Publications Office of the European Union, Luxembourg, 2026, JRC146927.
Image Credits: Not provided.

Keywords: peatlands; coastal lagoons; hydrology; wetland loss; Habitats Directive; Water Framework Directive; Earth Observation; ecological indicators; biodiversity; carbon storage