Freshwater Swamp Research Articles

High‐resolution analysis of sediments from Eighteen Mile Swamp (eastern Australia) records its transition from a fluctuating coastal lagoon to stable freshwater swamp

ABSTRACTThis research documents the paleoenvironmental evolution of Eighteen Mile Swamp on North Stradbroke Island (Minjerribah), Australia, from oscillating coastal lagoon into stable freshwater swamp over the last ca. 1600 years. We analyzed multiple sediment cores via physical description, acid sulfate soil assays, particle size analysis, diatom and pollen assemblages, photosynthetic pigment content, and Itrax XRF spectrometry, alongside ground‐penetrating radar cross‐sections. This provided a detailed ecological, geochemical and chronological framework, derived from radiocarbon, Pu and 210Pb dating, for the wetland's evolution. Results indicate spatial complexity in the timing of a pronounced shift in sedimentary conditions between ca. 300 and 1000 years ago, from estuarine mud to freshwater peat, marked by abrupt chemical and ecological changes. Unexpectedly, there were at least three and potentially many periods of dominant freshwater influence within the primarily estuarine phase, suggesting episodic estuarine closure and freshening by groundwater influx. Results provide critical insights into the complex response of subtropical wetland systems to environmental change, emphasizing the importance of interdisciplinary approaches in understanding both sedimentologic and geomorphic responses in coastal wetlands, and their potential vulnerability to future climate change. The study of Eighteen Mile Swamp is significant as it provides a detailed paleoenvironmental reconstruction that documents the wetland's evolving nature over the past two millennia. This research highlights the importance of understanding historical responses of wetlands to environmental changes, which helps inform their current and future management, conservation and restoration efforts, particularly in the context of climate change and human impacts. This study also serves as a tribute to the late Lynda Petherick, acknowledging her contributions in this field.

Provenance, environments, and tectonic signatures of Tanjong-Sandakan Formations, Northeast Sabah, Malaysia: Implications from sedimentology, palynology, and geochemistry

This study investigates marginal marine deposits found in the Tanjong and Sandakan formations from the Early to Late Miocene in Northeast Sabah. It examines sedimentology, trace elements (TE), rare earth elements (REE), hydrocarbon generation potential, and palynology to understand provenance, depositional environments, and paleoenvironmental conditions. Facies analysis identified four associations in the Tanjong and three in the Sandakan Formation, ranging from fluvial-deltaic to shallow marine environments. Mangrove-associated taxa, herbaceous and tree ferns typical of freshwater swamps, and coastal plants indicate a transition zone between terrestrial and marine environments. Siliciclastic deposits in the Northeast Sabah basin show varying redox conditions, ranging from dysoxic to oxic, as indicated by the Ni/Co, V/Cr, and U/Th ratios. These fluctuations may be linked to the tectonic evolution of the Sulu Sea and related sea-level lowstands. The low abundance of marine dinoflagellate cysts, along with high levels of rainforest and peat swamp pollen, suggests periods of subaerial exposure that contributed to the redox conditions. C-values and Sr/Cu ratios in the mudstone samples indicate semihumid to humid and warm conditions during the Miocene. Additionally, the distribution patterns of rare earth elements (REE) and the (La/Yb)N and Th/U ratios reveal consistent sedimentation rates in marginal marine environments. Palynofacies analysis indicates water column fluctuations, leading to oxidation during transport, resulting in low TOC values and kerogen types III and IV.Ternary diagrams of immobile TEs indicate that mudstone samples originate from active continental margins, linked to the rifting of the Sulu Sea during the Early to Middle Miocene. In contrast, sandstone samples exhibit characteristics of passive margins, likely due to recycled sediments from the early "Rajang Group Accretionary Complex." The plots for immobile TEs in the mudstones suggest intermediate and mafic sources, supporting the idea of uplift and erosion from deepwater sediments, as well as volcanic activity from the Cagayan and Sulu Arc systems. Sandstone samples may be sourced from acidic rocks associated with felsic intrusions in the Segama Valley, indicating a significant continental basement beneath the ophiolite. Keywords: Marginal marine, trace element, provenance, palynology, tectonic setting, Northeast Sabah.

How does the taxonomic and functional structure of plant communities differ between riverine and palustrine swamps?

AbstractQuestionsHow does the type of swamp, that is, riverine vs palustrine, shape understorey and overstorey plant communities? Beyond swamp type, how do spatial, topographic, soil and landscape characteristics determine the taxonomic and functional structure of swamp communities?LocationSouthern Québec, Canada.MethodsWe sampled riverine and palustrine swamp plant communities in two watersheds within two ecoregions with contrasting land use. At the site scale (n = 56), we analyzed differences between riverine and palustrine swamps in plant richness and cover, species composition, and mean and dispersion values for ecological and morphological traits. At the plot scale (n = 213), we assessed the relative influence of a set of environmental parameters on species richness and cover, as well as on trait values using mixed models and on species composition using redundancy analysis.ResultsSpecies composition and the mean value of traits varied significantly between the two types of swamps. While riverine swamps hosted more non‐native species and were composed of more mesophilic species, shorter in height and with dominant resource acquisition strategies, palustrine swamps sheltered more non‐vascular taxa and tall hygrophilous vascular species with more conservative resource strategies. The surrounding landscape and local microtopography within swamps had a significant effect on plant community structure. Species diversity and trait dispersion increased from agricultural‐dominated to forest‐dominated landscapes, and from homogeneous to heterogeneous substrates.ConclusionsHabitats provided by riverine and palustrine swamps are complementary for wetland biodiversity. Our results underline the need to develop conservation plans to protect a wide variety of freshwater swamp types; for example, management actions that maintain or promote heterogeneous topographic forms at the site scale, and continuity of forest cover at the landscape scale.

Assessment of Landscape‐Scale Fluxes of Carbon Dioxide and Methane in Subtropical Coastal Wetlands of South Florida

AbstractCoastal wetlands play a significant role in the storage of “blue carbon,” indicating their importance in the carbon biogeochemistry in the coastal zone and in global climate change mitigation strategies. We present airborne eddy covariance observations of CO2 and CH4 fluxes collected in southern Florida as part of the NASA BlueFlux mission during April 2022, October 2022, February 2023, and April 2023. The flux data generated from this mission consists of over 100 flight hours and more than 6,000 km of horizontal distance over coastal saline and freshwater wetlands. We find that the spatial and temporal heterogeneity in CO2 and CH4 exchange is primarily influenced by season, vegetation type, ecosystem productivity, and soil inundation. The largest CO2 uptake fluxes of more than 20 μmol m−2 s−1 were observed over mangroves during all deployments and over swamp forests during flights in April. The greatest CH4 effluxes of more than 250 nmol m−2 s−1 were measured at the end of the wet season in October 2022 over freshwater marshes and swamp shrublands. Although the combined Everglades National Park and Big Cypress National Preserve region was a net sink for carbon, CH4 emissions reduced the ecosystem carbon uptake capacity (net CO2 exchange rates) by 11%–91%. Average total net carbon exchange rates during the flight periods were −4 to −0.2 g CO2‐eq m−2 d−1. Our results highlight the importance of preserving mangrove forests and point to potential avenues of further research for greenhouse gas mitigation strategies.

LOSS OF BIODIVERSITY AND FOOD SECURITY IN NIGERIA

Nigeria is rich in biodiversity, boasting of diverse ecosystems and numerous species. The country's ecosystems range from semi-arid savannas to montane forests, floodplains, rainforests, freshwater swamps, and coastal vegetation. However, Nigeria's rich biodiversity, essential for agriculture and food security, is under severe threat, impacting adversely on food security. This study investigates the impact of oil pollution, deforestation, and desert encroachment on biodiversity loss within Nigeria's agricultural ecosystems. This study employed a comprehensive review of existing literature on the assessment of biodiversity loss in Nigeria's agricultural ecosystems due to pollution from oil spill, deforestation and desert encroachment. By analyzing the correlation between these environmental stressors and food security challenges, this study highlight the critical need for integrated conservation and agricultural strategies. The findings indicate that the loss of biodiversity has far-reaching implications, including malnutrition, food price volatility, and the erosion of rural livelihoods. The study emphasizes the pressing necessity of tackling these challenges in order to guarantee sustainable food security and ecological equilibrium in Nigeria. To address these interconnected issues, the study recommends a holistic approach that prioritizes sustainable practices, robust policies, and community engagement. By safeguarding Nigeria's biodiversity, we can ensure a sustainable food future for generations to come.

ENDEMISM AND CONSERVATION STATUS OF TREE SPECIES OF FRESHWATER SWAMP FOREST, PERAK TENGAH, MALAYSIA

ARTICLE HIGHLIGHTS- Approximately 3,364 tree individuals with a diameter at breast height (dbh) of 10.0 cm and above were assessed in the Perak Tengah freshwater swamp forest. - The study has recognised 58 species identified are new to Perak.- 72 tree species are listed as endemic, and 194 species are listed in the Red List of Threatened Species by The International Union for Conservation of Nature (IUCN).- This study mphasize the need to preserve ecology and mitigate threats. ABSTRACTThe forests of Peninsular Malaysia have long been recognized as a significant home of endemic species. The purpose of this study was to assess the endemism and conservation status of tree species present in the Perak Tengah freshwater swamp forest. A total of 150 plots (20 m × 20 m) were established in the study area using a random sampling design. Approximately 3,364 tree individuals with diameter at breast height (dbh) of 10.0 cm and above were enumerated in all plots. In the study area, 58 species identified are new to Perak, 72 tree species are listed as endemic, and 194 species are listed in the Red List of Threatened Species by IUCN. Thus, it is crucial to preserve the ecology and lessen the impact of threats in the Perak Tengah freshwater swamp forest, which is home to numerous endemic and endangered species.

Investigation of the pangas (Pangasianodon hypophthalmus) cultivation sustainability in cages at the Ratargul Freshwater Swamp Forest of Bangladesh

AbstractDetermining the most appropriate stocking density for a specific fish species in an ambient condition is essential for successful cage aquaculture in terms of profitability which is mainly governed by growth. The current study was conducted to ascertain which stocking density gives the best result of widely cultured species in cage aquaculture, pangas (Pangasianodon hypophthalmus), at swamp forest environment of Ratargul Freshwater Swamp Forest, Bangladesh in terms of growth, production and economic return. Fish were reared for 93 days at three stocking densities, namely 30, 40 and 50 fish/m3 which were denoted as FSD30, FSD40 and FSD50, respectively, containing three replications of each. Growth and yield comparisons indicated that the stocking density of fish had significant (p < 0.05) effects on growth rate and productivity. Fish cultivated at the maximum density (FSD50) had lower mean weights than fish reared at lower densities. The significantly highest mean weights (376.58 ± 14.65 g) and benefit–cost ratio (BCR) (1.617 ± 0.035) obtained from FSD30 show the suitability of this density in terms of fish growth and profitability of pangas in swamp forest environment.

Cenomanian terrestrial paleoenvironments from the Bohemian Cretaceous Basin in Central Europe and their implications for angiosperm paleoecology

In this paper, we reconstruct the vegetation communities of five terrestrial paleoenvironments from the Cretaceous (Cenomanian) Peruc-Korycany Formation of the Bohemian Cretaceous Basin in Czechia. Reconstructions are based on a synthesis of numerous studies of paleobotany, palynology, paleoecology, sedimentology and geochemistry analyses. Ordered in a transect from coastal marine settings to elevated hinterland regions, paleoenvironments and plant assemblages are reconstructed as follows: (1) Saltmarsh vegetation comprising a Frenelopsis-Classopollis assemblage; (2) Coastal freshwater swamp vegetation comprising a Cunninghamites-Taxodiaceaepollenites assemblage; (3) Meandering river floodplain vegetation comprising a Myrtophyllum-Perucipollis assemblage; (4) Braided river floodplain vegetation comprising a Eucalyptolaurus-Mauldinia assemblage; and (5) Vegetation of drier upland areas comprising fern prairies with angiosperms and Bennettitales - a Zamites-Ephedripites assemblage. Our study shows that in Cenomanian times, angiosperms were diversified, particularly in alluvial plains, where lauroid and platanoid angiosperms prevailed. Comparison of these Cenomanian paleoenvironments in Czechia with other Cenomanian paleoenvironments across Europe show a widespread dominance of angiosperms in the vegetation of alluvial plains across much of the continent. This contrasts with Barremian-Albian times when angiosperms occupied only disturbed habitats, and our findings suggest that angiosperm exchanged a ruderal (disturbed) strategy for a competitive strategy during the Albian-Cenomanian transition. Conversely, conifers dominated alluvial plains in Early Cretaceous times, while they rose to dominate saltmarshes and swamps in the Bohemian Cenomanian, exchanging a competitive strategy for a stress-tolerant strategy.

Note on Occurrence and Nomenclature of Tropidia maxwellii Ormerod (Asparagales: Orchidaceae) From North India

The nomenclature of Tropidia maxwellii Ormerod from Doon Valley (North India) has been confusing since its occurrencein 1971. The species was earlier treated as Tropidia curculigoides Lindl. and later, T. pedunculata Blume. The present article clarifies the nomenclature supplemented with colored photographs, illustrations, and a detailed description to facilitate identification. A short note on the conservational aspect and its habitat of freshwater swamps at Dehradun is also provided.

Palynology and palynofacies analysis of the Subathu Formation (Early Ypresian-Middle Lutetian) of Morni Hills, Haryana, India

Palynofossils and sedimentary organic matter recovered from two well exposed stratigraphic sections of the Subathu Formation (early Ypresian to middle Lutetian) outcropping in the Morni Hills, Haryana (Lesser Himalayas) are evaluated to interpret the depositional environment. The Morni Hills’ palynofloral assemblage consists of dinocysts, spores, pollen grains, fungal spores and ascostromata, and freshwater algae. Among these the significant palynotaxa are Pediastrum diffusus, P. angulatus Achomosphaera ramulifera, Adnatosphaeridium multispinosum, A. vittatum, Areoligera senonensis, Cleistosphaeridium diversispinosum, Cordosphaeridium fibrospinosum, C. gracile, Glaphyrocysta exuberans, Homotryblium abbreviatum, H. pallidum, H. tenuispinosum, Hystrichokolpoma salacium, Hystrichosphaerdium tubiferum, Lingulodinium machaerophorum, Operculodinium centrocarpum, Thalassiphora pelagica, Lygodiumsporites lakiensis, Todisporites major, Pteridacidites sp., Podocarpidites couperi and Neocouperipollis brevispinosus, etc. Five assemblage zones along with one barren zone are recognized on the basis of restricted species and variable abundance data of the examined palynofossils. Dinoflagellate cyst associations show a remarkable change from the older to younger horizons in the present succession. Variation in the composition of the assemblages from lower to upper horizons of the present succession might have been governed by several factors, viz. change in salinity concentration, decrease in water depth, and increase in proximity to the shoreline. Different types of organic matter types were also characterized, whose relative proportions in a vertical succession in both the sections, show changing depositional environmental gradients in this area. The study indicates that the basal carbonaceous shales seem to have been deposited in a freshwater swamp environment. Later, an open lagoon followed by closed lagoon and tidal flat environments are interpreted during the progradational sequence of the regressive phase.

A rich coprolite assemblage from Angeac-Charente (France): A glimpse into trophic interactions within an Early Cretaceous freshwater swamp

Coprolites (fossil droppings) are common in the Mesozoic fossil record. However, coprolite assemblages from continental settings have more rarely been quantitatively analysed than the marine ones. The excavation of the Berriasian continental Lagerstätte of Angeac-Charente (France) during the last decade has resulted in unearthing a vast number of fossils, including ca. 6000 coprolite specimens. This large collection, accompanied by spatially landmarked depositional data, offers a unique opportunity to assess the organism interactions in an Early Cretaceous freshwater swamp ecosystem. We assign the coprolites to nine morphotypes based on their morphology and contents (using tomography and thin-sections), and to four taphonomic categories. We compare the specimens to other fossil and recent droppings, including newly imaged crocodilian faeces. While the Angeac-Charente biota comprised animals of a range of different ecologies, including waters primary inhabitants (chelonians, crocodylomorphs, actinopterygians) and a variety of dinosaurs, the coprolites, together with other ichnological evidence, such as bite marks, seem to largely illustrate the activity of the crocodylomorphs in this ancient swamp. The assemblage is compared to previously analysed continental Cretaceous copro-assemblages from Europe and North Africa.

Complete genome sequence of Listeria seeligeri strain 43-1 isolated from a Danish forest freshwater swamp.

Here, we report the genome sequence of Listeria seeligeri 43-1 isolated from a Danish freshwater swamp using Oxford Nanopore sequencing. The isolate shared a high genomic similarity to two other L. seeligeri isolates from soil and water.

Leaf and twig traits predict habitat adaptation and demographic strategies in tropical freshwater swamp forest trees.

Differences in demographic and environmental niches facilitate plant species coexistence in tropical forests. However, the adaptations that enable species to achieve higher demographic rates (e.g. growth or survival) or occupy unique environmental niches (e.g. waterlogged conditions) remain poorly understood. Anatomical traits may better predict plant environmental and demographic strategies because they are direct measurements of structures involved in these adaptations. We collected 18 leaf and twig traits from 29 tree species in a tropical freshwater swamp forest in Singapore. We estimated demographic parameters of the 29 species from growth and survival models, and degree of association toward swamp habitats. We examined pairwise trait-trait, trait-demography and trait-environment links while controlling for phylogeny. Leaf and twig anatomical traits were better predictors of all demographic parameters than other commonly measured leaf and wood traits. Plants with wider vessels had faster growth rates but lower survival rates. Leaf and spongy mesophyll thickness predicted swamp association. These findings demonstrate the utility of anatomical traits as indicators of plant hydraulic strategies and their links to growth-mortality trade-offs and waterlogging stress tolerance that underlie species coexistence mechanisms in tropical forest trees.

Forest Vegetation Characteristics of the Garhwal Himalaya

General aspects of vegetation of the Shiwalik ranges and the Garhwal Himalaya between the altitudes : 400-4,200 m together with detailed floristic accounts of the typical forests, are provided. Main types of forests surveyed include moist sal bearing forests, tropical fresh-water swamp forests, tropical dry deciduous forests, Himalayan montane subtropical forests, Himalayan moist temperate forests, sub-alpine forests and alpine forests. Various forest types are illustrated by field photographs. It is noted that there is a general decline in the forest cover and forest degradation is on the increase because of population pressure for more cultivable land and increased tourist flow in the region. Serious efforts at natiopal level are needed to conserve the fast dwindling forest cover.

Holocene vegetation and climatic changes in the coastal tropical rainforests of Nigeria

A Mid-Late Holocene palynological and charcoal record of vegetation and climatic changes in the tropical rainforest of West Africa is presented based on sediment cores from four localities in southwest Nigeria. The localities namely Ahanve, Ogudu, Otolu-Lekki and Ikorigho are situated along gradients in riverine and coastal systems that drain into the Atlantic Ocean. The aim was to reconstruct the vegetation history of the tropical rainforest, infer past climate variabilities and ascertain the presence of humans and their impact on the landscape. The record shows that the Mid Holocene, c.6600-5600 BP, was characterised by predominantly diverse and extensive tropical rain forests that comprised lowland rainforest, mangrove swamp forest and freshwater swamp forest that are consistent with the African Humid Phase (AHP); climatic conditions were warm and wet with high sea levels. In the early stages of the Late Holocene, there is evidence of decline in the tropical rainforests with brief spells of climatic variability signalling the gradual end of the AHP. Subsequently, the pollen record revealed evidence of forest disturbance: specifically the replacement of the mangroves and lowland rainforests by coastal savannas and an Elaeis guineensis-dominated secondary forest, respectively, in Ahanve at cal. 3100 yr BP; and the decline and eventual recovery of the vegetation types in Ogudu after cal. 2760-2730 yr BP. These environmental disturbances are attributed to prolonged period of increased desiccation within a warm climate as well as the differentia in marine and riverine influence of both localities. Further decline in the tropical rainforest after cal. 1240-1200 yr BP were accompanied by substantial increase in oil palm (Elaeis guineensis), the emergence of exotic plants of South American and Asian origin, substantial increases in charcoal particles that were complemented by archaeological data. The pollen and charcoal data have shown that the decline of the tropical rain forests in the area beginning from the late Holocene was initially climate driven while subsequent and recent decline has been exacerbated by anthropogenic factors.

Gastrointestinal helminthiasis among Nigerian farmers in Delta North communities

Objective:To investigate the prevalence of gastrointestinal helminth infections among farmers of different age groups and the risk factors influencing disease transmission in different geographic settings with intermittent treatment in Delta North Agricultural Zone in Nigeria.Methods:This cross-sectional study was carried out among all age groups in some farming communities in freshwater swamp forest and lowland rainforest of Delta North Agricultural Zone. Kato Katz method was used to detect gastrointestinal helminth infections in stool samples. Study participants totalled 20 698 including 11215 (54.2%) males and 9483 (45.8%) females. Additionally, diagnostic tests performance forSchistosoma mansoniusing Kato Katz and PCR were compared.Results:This study identified six parasites namely,Schistosoma mansoni, Ascaris lumbricoides, hookworm,Trichuris trichiura, Enterobius vermicularisandStrongyloides stercoralis,with a total prevalence of 21.6%. The freshwater swamp forest had a slightly higher prevalence (21.8%) with six parasite species than that of the lowland rainforest (21.0%) with five species, but the difference was not statistically significant (P> 0.05). Factors that influenced disease transmission include sex, age, behaviour, type of infection, culture and environment, with vulnerabilities higher among children and females (P< 0.05). Additional investigation comparing Kato Katz method and PCR usingSchistosoma mansoni121 bp primer on 120 samples showed prevalence of 0.0% for Kato Katz and 4.2% for PCR.Conclusions:This study revealed persistent gastrointestinal helminth infections in areas where there is intermittent mass antihelminthic administration. This underscores the need for integrated control of gastrointestinal helminthiasis in farming communities.

Optimizing rice farming business inputs in shallow freshwater swamp (case study of Sungai Dua Village, Rambutan District, Banyuasin Regency)

Optimizing rice farming business inputs in shallow freshwater swamp (case study of Sungai Dua Village, Rambutan District, Banyuasin Regency)

Taraxerol abundance as a proxy for in situ mangrove sediment

Mangrove sediments are valuable archives of relative sea-level change if they can be distinguished in the stratigraphic record from other organic-rich depositional environments (e.g., freshwater swamps). Proxies for establishing environment of deposition can be poorly preserved (e.g., foraminifera) in mangrove sediment. Consequently, differentiating mangrove and freshwater sediment in the stratigraphic record is often subjective. We explore if biomarkers can objectively identify mangrove sediment with emphasis on their utility for reconstructing relative sea level. Our approach is specific to identifying in situ sediment, which has received less attention than identifying allochthonous mangrove organic matter. To characterize mangrove and non-mangrove (freshwater) environments, we measured n-alkane, sterol, and triterpenoid abundances in surface sediments at three sites in the Federated States of Micronesia. Elevated taraxerol abundance is diagnostic of sediment accumulating in mangroves and taraxerol is particularly abundant beneath monospecific stands of Rhizophora spp. Taraxerol was undetectable in freshwater sediment. Other triterpenoids are more abundant in mangrove sediment than in freshwater sediment. Using cores from Micronesian mangroves, we examine if biomarkers in sediments are indicative of in situ deposition in a mangrove, and have utility as a relative sea-level proxy. Taraxerol concentrations in cores are comparable to surface mangrove sediments, which indicates deposition in a mangrove. This interpretation is supported by pollen assemblages. Downcore taraxerol variability may reflect changing inputs from Rhizophora spp. rather than diagenesis. We propose that taraxerol is a proxy that differentiates between organic sediment that accumulated in mangrove vs. freshwater environments, lending it utility for reconstructing relative sea level.

Connectivity of floodplain influences riverine carbon outgassing and dissolved carbon transport

Rivers not only function as a conduit for the delivery of terrestrial constituents to oceans, but they also serve as an essential medium for biogeochemical processing of the constituents. While extensive research has been conducted on carbon transport in many rivers, little is known about carbon transformation in engineered rivers reconnected with their floodplain network. Being the largest distributary of the levee-confined Mississippi River (MR), the Atchafalaya River (AR) carries 25 % of the MR water, flowing through North America's largest freshwater swamp basin and emptying into the Gulf of Mexico. Previous studies reported that this 200-km long, 5–30-km wide river basin can remove a substantial amount of riverine nutrients and organic carbon. This study aimed to test the hypothesis that the AR emits significantly higher CO2 into the atmosphere as it flows through its extensive floodplain network than the levee-confined MR does. From January 2019 to December 2021, we conducted biweekly – monthly in-situ measurements in the lower AR at Morgan City and in the lower Mississippi River at Baton Rouge. Field measurements included partial pressure of dissolved CO2 (pCO2), water temperature, chlorophyll a, colored dissolved organic matter, dissolved oxygen, pH, and turbidity. During each field sampling, water samples were collected and analyzed for concentrations of dissolved organic and inorganic carbon (DOC and DIC). Mass transport of DOC and DIC and outgassing of CO2 were quantified for the two rivers. We found that pCO2 levels were significantly higher in the AR (mean: 3563 μatm; min-max: 1130–8650 μatm) than those in the MR (1931 μatm, 836–3501 μatm), resulting in a doubled CO2 outgassing rate in the AR (486 mmol m2 d−1) than in the MR (241 mmol m2 d−1). The AR had higher DOC (8.5 mg L−1) but lower chlorophyll a (153.9 AFU) when compared with the MR (7.5 mg L−1 and 164.0 AFU). Water temperature was constantly higher in the AR than in the MR, especially during the wintertime. Since the Mississippi-Atchafalaya River system is among the world's largest and most engineered river systems, our assessment offers a field case study to inform on the potential implications of reconnecting rivers with their floodplains networks.

Distribution of Endangered Dipterocarps in the Freshwater Swamp Forest of Parit Forest Reserve, Perak

Many endangered tree species suffered reductions in their population sizes due to forest fragmentation. A field survey was conducted to study the demographic structure of five threatened Dipterocarps species and to map their spatial distribution in freshwater swamp forests at Parit Forest Reserve, Perak, Malaysia. Of five species recorded, Shorea hemsleyana exhibited the highest number of individuals (i.e., 198), followed by Dipterocarpus semivestitus (35), S. macrantha (24), Hopea apiculata (14) and Vatica flavida (6). While the spatial distribution of D. semivestitus, S. macrantha, H. apiculata and V. flavida are appreared to be spatially dispersed, S. hemsleyana’s appears to be more localized.