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Sponges are well known to feed heterotrophically through suspension feeding, but their relationships with photosynthetic symbionts mean they also have the potential to utilise or release photosynthetically derived carbon. Here, we determined the nutritional mode of sponges that occurred seagrass meadows at two sites in the Wakatobi National Park (Hoga‐1 and 2), Indonesia from the near‐reef flat (d = 1.9 m), middle‐shore (d = 1.2 m) and high‐shore (d = 0.5 m) zones to assess the role they might play in nutrient fluxes. We measured photosynthetic pigment concentrations and in situ net primary production to dark respiration (P:R) ratios of eight sponge species representing 75%–100% of the total sponge assemblage biomass at the two sites. We found that six of eight sponge species were autotrophic, based on their instantaneous P:R ratios and estimated daily oxygen production/consumption. The proportion of autotrophic sponge biomass in the high and middle shore of the seagrass meadows ranged between 40% and 70%, and accounted for 98% and 81% of the biomass in the near‐flat zones. Our findings that many seagrass sponges are autotrophic challenges the general view that sponges are consumers of organic carbon from the water column. [ABSTRACT FROM AUTHOR]

Vertical vegetation differentiation is the most important form of spatial pattern in mountainous areas. It is of great significance to accurately divide vegetation into vertical zones for the study of mountain ecosystems and ecological protection. In order to accurately divide the vertical zone of mountain vegetation and determine the spatial distribution of mountain vegetation, the relationship between the vegetation index of various vegetation types and altitude was examined using remote sensing and geographic information technology. Taking Taibai Mountain, the main peak of the Qinling Mountains in China, as the study area, based on the difference in NDVI between summer and autumn (DNSA), this work constructed a DEM-NDVI scatter plot and quantified the boundary of the vertical zone by the half-peak width calculation method. The findings showed that: (1) the vertical distribution pattern of mountain vegetation may very well be reflected in the scatterplot that NDSA and DEM created; (2) Six vertical belts could be accurately identified to the meter level on Taibai Mountain's south slope. Up to the altitude, the oak forest zone from the bottom of the mountain to the elevation of 1919 m, the pine-oak mixed forest zone is distributed in 1919–2331 m, the birch forest is distributed in 2115–2585 m, the fir forest is distributed in 2516–3150 m, the redwood forest is distributed in 3109–3551 m, and the alpine scrub meadow is distributed in 3551 m to the peak. On the north slope, 1053–2087 m above sea level is oak forest, 2087–2693 is birch forest, 2562–3006 is fir forest, 2987–3513 m is redwood forest, and 3513 to the top of the mountain is alpine scrub meadow; and (3) the distribution pattern of the vegetation vertical belt on the DEM-NDVI scatter plot was essentially compatible with the vegetation classification results derived from remote sensing images. The DEM-NDVI scatter plot can reflect the average distribution of vegetation population and can more accurately express the characteristics of vegetation vertical zone changes with altitude. [ABSTRACT FROM AUTHOR]

In the present work, we assessed the contents of rare earth elements (REEs), including yttrium and scandium, in rhizomes and leaves of the widespread seagrass Zostera noltei Hornemann 1832 and in the nearby sediments from the Black Sea coast. The total REE content in the sediments was found to be much higher than in Z. noltei. The order of decrease in the major REE contents in the sediments and the seagrass rhizomes was identical, except for La and Y. La was the most abundant in the sediments, and Y in the rhizomes. The contents of all REEs in rhizomes of Z. noltei were 1.5–10 times higher than in the leaves. The highest difference in the REE contents was found for the minor elements (Sm–Lu). The translocation factors for Sc and the minor elements (excluding Tb) from the sediments to the rhizomes and from the rhizomes to the leaves turned out to be pairwise equal, which indicates the similarity of the REE translocation mechanisms. Comparing our results with the literature data, it is possible to conclude that the seagrass Z. noltei does not have an advantage in the REE accumulation over marine macroalgae. At the same time, large coastal deposits of this seagrass after storms allow us to consider it as a possible source of REEs in the future. [ABSTRACT FROM AUTHOR]

IntroductionSeagrass roots harbour diverse assemblages of microorganisms that likely benefit the growth and survival of meadows. Yet, restoration efforts rarely consider their effect on developing seagrass seedlings. Sediment origin should determine the types of rhizosphere and root-colonising (rhizoplane) microorganisms and thus the performance of seedlings during restoration, particularly for slow growing climax species like Posidonia. Recent Posidonia restoration attempts in South Australia used commercially sourced 'play pit sand' for seedling propagation and planting, but have been impacted by high mortality. More natural substrates like seagrass meadow sediment have not been previously investigated for suitability over conventional substrates with regard to seedling growth and survival.MethodsTo assess the relevance of seagrass associated microorganisms in the growth of Posidonia angustifolia seedlings, we investigated the bacterial communities from tank-raised seedlings propagated in autoclave treated and untreated 'play pit sand' and meadow mix (comprising a 1:3 ratio of natural meadow sediment and beach sand) over a 12-week period. Autoclave treatment was adopted in order to diminish the bacterial load prior to planting and thus inform their contribution (if any) on early seedling growth. Samples for bacterial community analysis and seedling growth measurements (numbers and total length of roots/leaves, root diameter, seedling weight, starch reserves) were taken at 4 and 12 weeks. Bacterial assemblages were surveyed from DNA extracts from bulk and rhizosphere sediments and root tissues, as well as from swabs of P. angustifolia fruit, established meadow sediment and water samples prior to seedling propagation, by constructing Illumina 16S rRNA gene libraries.ResultsWhile most growth measurements did not vary significantly between sediment type or treatment, proportional growth of roots versus leaves (as expressed as a pseudo root:shoot ratio) was significantly related to treatment, sediment type and seed length. Seedlings from meadow mix invested more in leaves, regardless of treatment, when compared to play sand. Autoclave treatment increased investment in roots for play sand but increased the investment in leaves for meadow mix. Bacterial communities differed significantly between sediments and between sample types (bulk, rhizosphere and roots), with the roots from meadow mix seedlings containing an increased abundance of various potentially beneficial bacterial taxa.DiscussionWhile such changes appear to affect the early development of seedlings, bacterial community dynamics are also likely coupled to changes in nutrient availability. Further research is thus required to disentangle host seedling growth-nutrient-bacterial community dynamics with the view to identifying microbes that may support the growth and vigour of seedlings under different nutrient conditions as part of future restoration efforts.

Studies related to seagrass ecology, conservation, and management are sparse and highly biased in India. Even though the geographical distribution of seagrass is diverse in India, about 74% of the scientific publications have been made from Palk Bay and the Gulf of Mannar from Tamilnadu. Chilika, the largest lagoon in Asia, harbors the second largest seagrass meadow in India 22% of the total. The lagoon acts as a potential blue carbon stock and helps in thriving a rich floral and faunal biodiversity. However, the critical role of seagrass in this unique lagoon ecosystem is still poorly understood. This review is aimed at synthesizing the published literature about seagrass in Chilika. We believe this information would encourage more in-depth and diverse seagrass studies in the region and identify future priority areas for research. A total of seven species have been recorded from 169.2 sq. km of seagrass patch in Chilika. For the last two decades, no significant signs of decline in seagrass beds from this lagoon have been reported. Still, various natural and anthropogenic stressors could put this unique ecosystem under severe stress. Moreover, lax enforcement of existing legislation and a general lack of knowledge among the stakeholders about their ecosystem services can be significant impediments to their conservation. More targeted research on Chilika seagrass in changing climate regimes and their sustainable intensification is the need of the hour. [ABSTRACT FROM AUTHOR]

Seagrass meadows are an important component of coastal ecosystems globally, and they capture and store organic carbon in living biomass and sediments. Geographical estimates of blue carbon in seagrass habitats are regionally biased, with limited information from the Indo-Pacific region, including Indonesia. Seagrass extent in Indonesia is declining rapidly, and it has been suggested that marine protected areas (MPAs) are an important instrument to support protection of seagrass ecosystems and their services. Thus, this study is aimed at quantifying and comparing sedimentary carbon stocks and sources of organic carbon from seagrass meadows located in undisturbed areas outside MPA, disturbed areas outside MPA, and within MPA in three small islands in Indonesia. The sediment carbon stocks from this study ranged from 19.81 to 117.49 Mg C ha−1, with the highest stock measured inside MPA (77.15 ± 1.38 Mg C ha−1), followed by undisturbed outside MPA (36.08 Mg C ha−1), and the lowest stock at disturbed outside MPA (21.86 ± 0.31 Mg C ha−1). The predominant source of organic carbon in disturbed meadows was from coastal POM (particulate organic matter, ~ 36%), while in MPA and undisturbed sites, the main source was from seagrass, with ~ 38% and ~ 60% contributions, respectively. The results of this study add more data and information on seagrass blue carbon potential from three different islands with different degrees of disturbance in Indonesia. [ABSTRACT FROM AUTHOR]

Seagrasses harbour different and rich epiphytic bacterial communities. These microbes may establish intimate and symbiotic relationships with the seagrass plants and change according to host species, environmental conditions, and/or ecophysiological status of their seagrass host. Although Posidonia oceanica is one of the most studied seagrasses in the world, and bacteria associated with seagrasses have been studied for over a decade, P. oceanica's microbiome remains hitherto little explored. Here, we applied 16S rRNA amplicon sequencing to explore the microbiome associated with the leaves of P. oceanica growing in two geomorphologically different meadows (e.g. depth, substrate, and turbidity) within the Limassol Bay (Cyprus). The morphometric (leaf area, meadow density) and biochemical (pigments, total phenols) descriptors highlighted the healthy conditions of both meadows. The leaf-associated bacterial communities showed similar structure and composition in the two sites; core microbiota members were dominated by bacteria belonging to the Thalassospiraceae, Microtrichaceae, Enterobacteriaceae, Saprospiraceae, and Hyphomonadaceae families. This analogy, even under different geomorphological conditions, suggest that in the absence of disturbances, P. oceanica maintains characteristic-associated bacterial communities. This study provides a baseline for the knowledge of the P. oceanica microbiome and further supports its use as a putative seagrass descriptor. [ABSTRACT FROM AUTHOR]

Summary: The response of Posidonia oceanica meadows to global warming of the Eastern Mediterranean Sea, where the increase in sea surface temperature (SST) is particularly severe, is poorly investigated.Here, we reconstructed the long‐term P. oceanica production in 60 meadows along the Greek Seas over two decades (1997–2018), using lepidochronology. We determined the effect of warming on production by reconstructing the annual and maximum (i.e. August) SST, considering the role of other production drivers related to water quality (i.e. Chla, suspended particulate matter, Secchi depth).Grand mean (±SE) production across all sites and the study period was 48 ± 1.1 mg DW per shoot yr−1. Production over the last two decades followed a trajectory of decrease, which was related to the concurrent increase in annual SST and SSTaug. Annual SST > 20°C and SSTaug > 26.5°C was related to production decline (GAMM, P < 0.05), while the rest of the tested factors did not help explain the production pattern.Our results indicate a persistent and increasing threat for Eastern Mediterranean meadows, drawing attention to management authorities, highlighting the necessity of reducing local impacts to enhance the resilience of seagrass meadows to global change threats. [ABSTRACT FROM AUTHOR]

Seagrasses provide ecosystem services worth USD 2.28 trillion annually. However, their direct threats and our incomplete knowledge hamper our capabilities to protect and manage them. This study aims to evaluate if the NICFI Satellite Data Program basemaps could map Seychelles' extensive seagrass meadows, directly supporting the country's ambitions to protect this ecosystem. The Seychelles archipelago was divided into three geographical regions. Half-yearly basemaps from 2015 to 2020 were combined using an interval mean of the 10th percentile and median before land and deep water masking. Additional features were produced using the Depth Invariant Index, Normalised Differences, and segmentation. With 80% of the reference data, an initial Random Forest followed by a variable importance analysis was performed. Only the top ten contributing features were retained for a second classification, which was validated with the remaining 20%. The best overall accuracies across the three regions ranged between 69.7% and 75.7%. The biggest challenges for the NICFI basemaps are its four-band spectral resolution and uncertainties owing to sampling bias. As part of a nationwide seagrass extent and blue carbon mapping project, the estimates herein will be combined with ancillary satellite data and contribute to a full national estimate in a near-future report. However, the numbers reported showcase the broader potential for using NICFI basemaps for seagrass mapping at scale. [ABSTRACT FROM AUTHOR]

Seagrass beds in Florida Bay are home to many ecologically and economically important species. Anthropogenic press perturbation via alterations in hydrology and pulse perturbations such as drought can lead to hypersalinity, hypoxia, and sulfide toxicity, ultimately causing seagrass die-offs. Florida Bay has undergone two large-scale seagrass die-offs, the first in the late 1980s and early 1990s and the second in 2015. Post-die-off events, samples were collected for stable isotope analysis. Using historical (1998–1999) and contemporary (2018) stable isotope data, we examine how food webs in Florida Bay have changed in response to seagrass die-off over time by measuring contributions of basal sources to energy usage and using trophic niche analysis to compare niche size and overlap. We examined three consumer species sampled in both time periods (Orthopristis chrysoptera, Lagodon rhomboides, and Eucinostomus gula) in our study. Seagrass production comprised the majority of source usage in both datasets. However, contemporary consumers had a mean increase of 18% seagrass usage and a mean decrease in epiphyte usage of 7%. The shift in trophic niche from epiphyte usage (green pathway) toward seagrass usage (brown pathway) may indicate that food web browning is occurring in Florida Bay. [ABSTRACT FROM AUTHOR]

Understanding sexual reproduction and recruitment in seagrasses is crucial to their conservation and restoration. Flowering, seed production, seed recruitment, and seedling establishment data for the seagrass Posidonia australis was collected annually between 2013 and 2018 in meadows at six locations around Rottnest Island, Western Australia. Variable annual rates of flowering and seed production were observed among meadows between northern and southern sides of the island and among years. Meadows on the northern shore consistently flowered more intensely and produced more seeds across the years of the survey. Inter‐site variation in clonal diversity and size of clones, seed production, wind and surface currents during pollen and seed release, and the large, but variable, impact of seed predation are likely the principal drivers of successful recruitment into established meadows and in colonizing unvegetated sands. The prolific but variable annual reproductive investment increases the probability of low levels of continuous recruitment from seed in this seagrass, despite high rates of abiotic and biotic disturbance at seedling, shoot, and patch scales. This strategy also imparts a level of ecological resilience to this long‐lived and persistent species. [ABSTRACT FROM AUTHOR]

Ocean acidification and warming could affect animal physiology, key trophic interactions and ecosystem functioning in the long term. This study investigates the effects of four pH−temperature combination treatments simulating ocean acidification (OA), ocean warming (OW) and combined OA and OW conditions (FUTURE) relative to ambient present-day conditions (PRESENT) on the grazing of the juveniles of two seagrass-associated invertebrates namely the sea cucumber Stichopus cf. horrens and topshell Trochus maculatus over a 5-day exposure period. Diel and feeding activity of both species increased under OW and FUTURE to some extent, while the nighttime activity of Trochus but not Stichopus decreased under OA relative to PRESENT during the first 2 days. Fecal production of Stichopus did not differ among treatments, while the lowest fecal production of Trochus was observed under OA during the first 24 h of grazing. These responses suggest that Trochus may be initially more sensitive to OA compared with Stichopus. Interestingly, fecal production of Trochus in FUTURE was significantly higher than OA, suggesting that warming may ameliorate the negative effect of acidification. Diel activity, feeding and fecal production after 5 days did not differ among treatments for both species, suggesting acclimation to the acute changes in temperature and pH after a few days, although Stichopus acclimated rapidly than Trochus. The ability of the two juvenile invertebrate grazers to rapidly acclimate to increased temperature and lowered pH conditions after short-term exposure may favor their survival under projected changes in ocean conditions. [ABSTRACT FROM AUTHOR]

Summary: Climate change and extreme climatic events, such as marine heatwaves (MHWs), are threatening seagrass ecosystems. Metabolomics can be used to gain insight into early stress responses in seagrasses and help to develop targeted management and conservation measures.We used metabolomics to understand the temporal and mechanistic response of leaf metabolism in seagrasses to climate change. Two species, temperate Posidonia australis and tropical Halodule uninervis, were exposed to a combination of future warming, simulated MHW with subsequent recovery period, and light deprivation in a mesocosm experiment.The leaf metabolome of P. australis was altered under MHW exposure at ambient light while H. uninervis was unaffected. Light deprivation impacted both seagrasses, with combined effects of heat and low light causing greater alterations in leaf metabolism. There was no MHW recovery in P. australis. Conversely, the heat‐resistant leaf metabolome of H. uninervis showed recovery of sugars and intermediates of the tricarboxylic acid cycle under combined heat and low light exposure, suggesting adaptive strategies to long‐term light deprivation.Overall, this research highlights how metabolomics can be used to study the metabolic pathways of seagrasses, identifies early indicators of environmental stress and analyses the effects of environmental factors on plant metabolism and health. [ABSTRACT FROM AUTHOR]

Hypoxia is a major emerging threat to coastal ecosystems, which is closely related to the decline in seagrass meadows, but its damage mechanism is still unclear. This study found that hypoxia at night significantly reduced the photosynthetic capacity of Enhalus acoroides after reillumination. Photosystem II (PSII) was damaged by high‐light stress during daytime low‐tide exposure, but high‐light‐damaged PSII of E. acoroides could recover part of its activity indark normoxic seawater to maintain the normal operation of photosynthesis after reillumination during the next day. However, hypoxia inhibited the recovery of damaged PSII under darkness. By transcriptomic analysis and inhibitor verification experiments, dark hypoxia was shown to inhibit respiration, thereby reducing ATP production and preventing ATP from being transported into chloroplasts, which, in turn, led to an insufficient supply of energy required for PSII to recover. This study demonstrated that hypoxia has several negative impacts on the photosynthetic apparatus of E. acoroides at night reducing photosynthetic capacity after reillumination, which may be an important factor leading to the decline of the seagrass meadows. Summary Statement: 1.Hypoxia lowers respiratory ATP production and prevents ATP from being transported into the chloroplasts, thus inhibiting high‐light‐damaged photosystem II (PSII) recovery of Enhalus acoroides at night.2.The inhibition of PSII recovery reduces the photosynthetic capacity of E. acoroides after reillumination. [ABSTRACT FROM AUTHOR]

Seagrasses provide crucial ecosystem services in the coastal environment, but are under increasing threat associated with anthropogenic activities. Seagrass meadows effectively trap suspended sediment, a key vector for trace metal transport, by altering local hydrodynamic conditions around their leaves and stems. As a result, seagrass meadows often have different geochemical sediment characteristics compared to adjacent bare sediments and may accumulate higher concentrations of trace metals. The aim of this systematic review was to identify research trends and knowledge gaps in the relationships between metals and seagrasses. The systematic search of the literature identified a total of 191 relevant articles. Although seagrasses have a broad geographic distribution, the highest diversity and endemism exists in the Indo-Pacific region, yet most studies (40%) were conducted in the Mediterranean Sea. There were also taxonomic gaps with some common species groups, including Amphibolis and Thalassodendron spp., being poorly studied. The reviewed studies examined the relationship between seagrass and 39 metal elements. There were no studies examining rare-earth elements (REEs) or platinum-group elements (PGEs), both of which are critical classes of metals in emerging technologies. Furthermore, the review determined that all 191 studies focused on the impact of metals on seagrasses, while only six also considered the effect of seagrasses on metal geochemistry in sediments. We conclude that further research is necessary to address these key gaps in knowledge to better understand the role(s) of seagrasses in the distribution, immobilization, and release of trace metals in coastal ecosystems. [ABSTRACT FROM AUTHOR]

The aim of this study was to elucidate the taxonomy of the common but overlooked epiphytic coralline algae species from shallow reefs and seagrass meadows of the Abrolhos Archipelago, Brazil. Two thin (two vegetative cells thick) epiphytic coralline species were recorded: Lithophyllum epiphyticum sp. nov. and Hydrolithon farinosum. Molecular analysis from psbA genetic marker confirmed the position of L. epiphyticum into Lithophylloideae and revealed a phylogenetic relationship with an undescribed Lithophyllum from Italy. Thin thallus (2–3 cells thick) and cells lining the pore of tetrasporangial conceptacles protruding laterally occluding the canal, either partially or totally, are its main diagnostic characteristics. Hydrolithon farinosum is herein described in detail for Brazil, and its worldwide distribution is then discussed. [ABSTRACT FROM AUTHOR]

The extent of seagrasses has declined globally, with restoration through transplantation seen as an important tool for reversing population loss, yet restoration studies for African seagrass species are scarce. This study investigated the use of different planting patterns (straight‐line, compact, and star) and core sizes (11, 18, and 25 cm Ø) in transplanting ecotypes (intertidal and subtidal) in the predominantly open Knysna and temporarily closed Klein Brak estuaries in South Africa. Cores of the endangered seagrass, Zostera capensis, were transplanted in two experimental repeats per ecotype and core size along transects to investigate survival of plants post‐transplant. No significant differences were observed among core sizes, patterns, or ecotypes in the Knysna Estuary, but cores with the compact pattern had better survival rates in the Klein Brak Estuary. Holes left by the smallest cores in donor sites recovered faster through sediment deposition compared to larger holes. Our study demonstrated that seagrass restoration in South Africa is challenging due to limited suitable habitats and strong environmental variability in estuarine ecosystems. It is important that careful consideration, including of genomic diversity and population structure, as well as ecological similarity between donor and recipient populations must be made for each restoration site when assessing its restoration potential. Effective "no‐take bait zones" and upstream catchment management will be important for protecting potential donor meadows. [ABSTRACT FROM AUTHOR]

Posidonia oceanica (L.) Delile, an endemic species that plays a significant role in the ecosystem from the Strait of Gibraltar to the Sea of Marmara, is under the influence of the Anthropocene. The conservation of the species, which is one of the invaluable resources of the Mediterranean Sea, is essential to protect its unique ecological system. Nonetheless, the detection of the locations where the species exists is a prerequisite for its protection and the preservation of the associated habitat. Hence, the current investigation depicts the extent of P. oceanica coverage in Paşalimanı Island and the Narlı area of the Kapıdağ Peninsula located in the Sea of Marmara, which is the northern limit of the distribution of this species. The results obtained supported the determination of the area of P. oceanica in the Narlı region as 4.676 ha, and also the updating of this area to 21.861 ha for Paşalimanı Island, thus improving the existing information on their habitats. [ABSTRACT FROM AUTHOR]

The filamentous green alga Chaetomorpha ligustica (Cladophoraceae, Cladophorales) was recorded covering seagrass meadows at Pāuatahanui Inlet, New Zealand. Species of the genus Chaetomorpha are difficult to identify by their morphologically, and the identification of C. ligustica was confirmed by sequencing the 28S rRNA large subunit providing a high level of confidence in the species designation. In November 2019, we found C. ligustica intertwined with Ulva spp. forming dense, heavy and entangled structures. Here we report, for the first time, negative impacts of this species upon meadows of the New Zealand seagrass Zostera muelleri. We observed a significant loss of seagrass cover and evidence of anoxia under C. ligustica mats two weeks from the first sighting. Chaetomorpha ligustica can easily be misidentified in the field. This may lead to over- and under-reporting of species, and we recommend the need for more careful identification of macroalgal blooms in the future and further research on growth requirements and origins of strains. [ABSTRACT FROM AUTHOR]

Seagrass Zostera muelleri has been reported to reproduce mainly asexually in New Zealand. However, a recent study in Tauranga Harbour suggested that flowering might occur more often than previously thought. Here we provide evidence of intertidal seagrass flowering events in six New Zealand estuaries in which it has not before been documented. Further research on seagrass sexual reproduction is desirable as we hypothesise that either flowering events have formerly been missed due to the cryptic nature of the flowers, or that sexual reproduction is emerging as a response to increasing pressures on seagrass ecosystems. In addition, with evidence of seagrass decline occurring globally, and likely also in New Zealand, we recommend collection of seagrass seeds to preserve genetic variability and to attempt restoration efforts through assisted sexual reproduction techniques that have not yet been used in New Zealand. [ABSTRACT FROM AUTHOR]

A transfer-prepared specimen of Lepidotes (Actinopterygii, Lepisosteiformes) from the Posidonia Shale Formation of south Germany is tentatively identified specifically as L. gigas. The genus and its species are insufficiently defined and in need of revision. The new specimen reveals details of the cranial and pectoral girdle skeletal architecture and previously unknown osteological features of Lepidotes, such as a large foramen on the maxilla and the formation of two tooth-bearing clavicle elements (serrated appendages). Maxillary foramina are also known in the related contemporaneous lepisosteiform Mengius and possibly served for passage of nerve branches supplying either a maxillary pit-line or cutaneous sense organs (taste buds) in a thickened upper lip or barbels. The clavicle elements agree morphologically with those of the Recent Amia. Their function remains obscure. [ABSTRACT FROM AUTHOR]

Macrophytes and seagrasses play a crucial role in a variety of functions in marine ecosystems and respond in a synchronized manner to a changing climate and the subsequent ecological status. The monitoring of seagrasses is one of the most important issues in the marine environment. One rapidly emerging monitoring technique is the use of acoustics, which has advantages compared to other remote sensing techniques. The acoustic method alone is ambiguous regarding the identities of backscatterers. Therefore, a computer program package was developed to identify and estimate the leaf biometrics (leaf length and biomass) of one of the most common seagrasses, Posidonia oceanica. Some problems in the acoustic data were resolved in order to obtain estimates related to problems with vegetation as well as fisheries and plankton acoustics. One of the problems was the "lost" bottom that occurred during the data collection and postprocessing due to the presence of acoustic noise, reverberation, interferences and intense scatterers, such as fish shoals. Another problem to be eliminated was the occurrence of near-bottom echoes belonging to submerged vegetation, such as seagrasses, followed by spurious echoes during the survey. The last one was the recognition of the seagrass to estimate the leaf length and biomass, the calibration of the sheaths/vertical rhizomes of the seagrass and the establishment of relationships between the acoustic units and biometrics. As a result, an autonomous package of code written in MATLAB was developed to perform all the processes, named "POSIBIOM", an acronym for POSIdonia BIOMass. This study presents the algorithms, methodology, acoustic–biometric relationship and mapping of biometrics for the first time, and discusses the advantages and disadvantages of the package compared to the software dedicated to the bottom types, habitat and vegetation acoustics. Future studies are recommended to improve the package. [ABSTRACT FROM AUTHOR]

An organism’s habitat preference may shift to one of greater structural complexity to maximize protection from predatory attack. In south-eastern Australian coastal seascape, seagrass beds, sandy substratum and/or rocky algal reef border each other forming a matrix of varying habitat configurations with varying protection potential. We investigated the change in habitat selection in four Australian seagrass fish species, Stigmatopora argus, Acanthaluteres spilomelanurus, Pelates sexlineatus and Atherinosoma microstomata with the inclusion of predatory threat using tank experiments. The 250L, 90 cm internal diameter experimental tank contained three habitats – seagrass, sand and rock arranged in an unbroken circular path creating three distinct edge combinations and resulting in six sections of varying levels of complexity and heterogeneity. A transparent inner wall separated the habitat matrix from the central test chamber, which contained and demarcated “zone of decision”. Each test fish (n=123) was placed in the tank centre for 2–3 minutes in an isolation tube to acclimatize before being released to make its selection. This was repeated for each test fish first without predatory threat then with threat. S. argus spent significantly more time in the rock section (paired t-test: p= 0.038) and less time in the seagrass-sand section (paired t-test: p=0.05) when under threat. A. spilomelanurus spent significantly less time in homogeneous seagrass when threatened (paired t-test: p = 0.016) and displayed a non-significant increased selection of sections containing rock when threatened. Shifts to the complex rocky substratum preference with predatory threat was demonstrated along with the importance of a suite of different habitats for a species’ survival. [ABSTRACT FROM AUTHOR]

The study of how organisms grow is a fundamental aspect of palaeontology. Growth in teleosauroids is poorly understood and little studied, especially in an ontogenetic sense. We investigate growth rates of the most common and abundant teleosauroid, Macrospondylus bollensis, in which a large sample of multiple body sizes is available from the Posidonienschiefer Formation (Posidonia Shale) of southwestern Germany. We perform linear regression analyses on 62 specimens of Macrospondylus (16 juveniles, 7 subadults and 39 adults) using 21 cranial and postcranial measurements. Our results show that juvenile, subadult and adult individuals have near‐isometric or isometric growth throughout much of the body. Notably, we find that in Macrospondylus: (1) the femur grows at a faster rate than the skull and hindlimb zeugopodium; (2) the forelimb and hindlimb grow at the same rate; and (3) there is distinct ontogenetic signal in the growth of the orbit and supratemporal fenestra. We also find that limb scaling in Macrospondylus is somewhat comparable to that seen in the extant gavialids Gavialis gangeticus and Tomistoma schlegelii. Last, we examine evolutionary allometry in skull length relative to body size in Crocodylomorpha using femoral length as a proxy, which shows a near‐isometric trend. Non‐thalattosuchian crocodylomorphs (with the exception of one pholidosaurid and one dryosaurid taxon) are differentiated from thalattosuchians due to their shorter skulls, as previously suggested, but the scaling relationship with femur length remains unchanged. [ABSTRACT FROM AUTHOR]

Seagrasses are habitat-forming species that support biodiversity and a wide range of associated ecosystem services, from blue carbon capture to providing nursery areas for a variety of organisms. Their decline has been documented worldwide and is attributed to human impacts ranging from habitat loss and eutrophication to the effects of climate change. However, recent recovery trends have also been documented due to reductions in stressors, passive and active restoration, and even changes in environmental conditions owing to local management. In this study, we document for the first time the occurrence of Zostera noltei in the downstream area of the River Minho Estuary. This occurrence was unexpected given the hydrological conditions of the estuary, characterised by dredging and siltation. We reconstructed the occurrence and historical distribution of seagrass beds, and showed that they have existed in the region for more than a decade. The current distribution area was mapped using high-resolution multispectral remote sensing techniques, and in situ photoquadrats to complement the remote sensing information with an evaluation of the seagrass cover. A current seagrass area of 0.81 ha was found with an average cover of 70%. However, the Minho Estuary continues to be strongly affected by sediment deposition, which may affect the seagrass population in the long term. Continued surveys are recommended to confirm the long-term trend of colonisation of this important habitat, which ultimately provides so many benefits to coastal ecosystems and humankind. [ABSTRACT FROM AUTHOR]

Simple Summary: The French Polynesian islands represent a unique insular system in the Pacific Ocean. Previous surveys of the marine flora of French Polynesia were mostly established on traditional morphology-based taxonomy. DNA barcoding allowed us to provide a major revision of French Polynesian marine flora, with an updated total of 702 species from French Polynesia, including 119 species of Chlorophyta, 169 Cyanobacteria, 92 Ochrophyta, 320 Rhodophyta, and 2 species of seagrasses (Alismatales)—nearly a two-fold increase from previous estimates. In addition to improving and refining our knowledge of French Polynesian marine flora, this study also provides a valuable DNA barcode reference library for identification purposes and future taxonomic and conservation studies. A significant part of the diversity uncovered corresponds to unidentified lineages, which will need careful taxonomic examination. Located in the heart of the South Pacific Ocean, the French Polynesian islands represent a remarkable setting for biological colonization and diversification, because of their isolation. Our knowledge of this region's biodiversity is nevertheless still incomplete for many groups of organisms. In the late 1990s and 2000s, a series of publications provided the first checklists of French Polynesian marine algae, including the Chlorophyta, Rhodophyta, Ochrophyta, and Cyanobacteria, established mostly on traditional morphology-based taxonomy. We initiated a project to systematically DNA barcode the marine flora of French Polynesia. Based on a large collection of ~2452 specimens, made between 2014 and 2023, across the five French Polynesian archipelagos, we re-assessed the marine floral species diversity (Alismatales, Cyanobacteria, Rhodophyta, Ochrophyta, Chlorophyta) using DNA barcoding in concert with morphology-based classification. We provide here a major revision of French Polynesian marine flora, with an updated listing of 702 species including 119 Chlorophyta, 169 Cyanobacteria, 92 Ochrophyta, 320 Rhodophyta, and 2 seagrass species—nearly a two-fold increase from previous estimates. This study significantly improves our knowledge of French Polynesian marine diversity and provides a valuable DNA barcode reference library for identification purposes and future taxonomic and conservation studies. A significant part of the diversity uncovered from French Polynesia corresponds to unidentified lineages, which will require careful future taxonomic investigation. [ABSTRACT FROM AUTHOR]

Seagrass beds support diverse macrofaunal communities, and collectively they influence carbon and nutrient cycles; however, we know little on how seagrass disturbance alters this relationship. In Newfoundland, Canada, the invasive European green crab Carcinus maenas threatens the seagrass Zostera marina by snipping and uprooting seagrasses while foraging and burrowing. In order to understand the effects of seagrass disturbance on macrofaunal diversity and ecosystem functioning within sediments, we experimentally uprooted small patches of seagrass and compared rates of oxygen and nutrient fluxes from sediment cores from uprooted (disturbed) patches, seagrasses, and unvegetated sediments nearby. In parallel, we assessed macrofaunal biodiversity (taxonomic and functional) and sedimentary (granulometric properties and organic matter content/freshness) variables in all three of these treatments over a three‐month period. As expected, macrofaunal abundance, species richness and functional richness declined significantly initially in disturbed cores, although this decrease had little effect on benthic flux rates. Over 3 months, macrofaunal colonization of the disturbed sediments resulted in abundances similar to the natural seagrass and unvegetated treatments. We also observed a change in nutrient flux rates that we attribute to seasonal shifts in regeneration pathways rather than macrofaunal community recovery, suggesting a lesser role for macrofaunal diversity in carbon and nutrient cycling in dynamic nearshore habitats than in deeper water. Our results demonstrate the impacts of green crab‐mediated seagrass disturbance on macrofaunal abundance and community structure while highlighting their potential capacity for rapid stabilization, and emphasize the strength of large‐scale seasonal environmental changes on ecosystem processes. [ABSTRACT FROM AUTHOR]

Comprehensive information on seagrass biodiversity indicators, such as species composition, percentage cover, and biomass carbon stock, remains limited across various regions globally. Mapping these indicators using remote sensing images requires extracting maximum information from the input images to achieve effective results. This study aims to map seagrass distribution, percent cover (PC), and aboveground carbon stock (AGC) as biodiversity indicators in the optically shallow waters surrounding Pari Island. We integrate WorldView-2 (WV2) derivatives, field seagrass data, and RF classification and regression algorithms to accomplish this objective. The WV2 image derivatives encompass surface reflectance bands, band ratios, mean and variance co-occurrence texture bands, and principle component bands. These inputs are used individually and collectively for mapping, employing a random forest algorithm trained with field seagrass data. Our results demonstrate that the most accurate benthic habitat map achieves an overall accuracy (OA) of 65.2%, with a user's accuracy of 65.2% and a producer's accuracy of 72.8% for the seagrass-dominated class. Seagrass PC mapping yields a root mean square error (RMSE) of 17.1%, with an average PC of 47.4 ± 9.9%. Seagrass AGC mapping achieves an RMSE of 5.0 g C m-2, with an average AGC range of 6.2 -- 29.1 g C m-2, estimating the study area's aboveground biomass carbon stock at 27.9 tons C. Combined inputs produce the most accurate results for all biodiversity indicators, emphasizing the importance of utilizing combined bands from SR band derivatives to maximize information input for training mapping algorithms, instead of using derivative bands individually or as replacements for the initial SR bands. [ABSTRACT FROM AUTHOR]

Many sessile and tube-dwelling polychaetes can act as ecosystem engineers, influencing the physical–chemical and biological characteristics of their habitats, increasing structural complexity. Thus, they are considered structuring species. In summer of 2021, in southern Sicily (Ionian Sea), benthic assemblages dominated by Ampharetidae Amage adspersa were discovered via an ROV survey at a depth range between 166 and 236 m on muddy horizontal seafloor. Large aggregations of this species (up to 297.2 tubes m−2), whose tubes are formed from Posidonia oceanica debris, occurred alternately with tube-free areas. The area was characterized by the sporadic presence of vulnerable sea pens Funiculina quadrangularis (up to 0.08 col. m−2) and Virgularia mirabilis (up to 0.16 col. m−2), and it was possible to detect signs of trawling as well the presence of marine litter (up to 24.0 items 100 m−2). The habitat description, distribution, and density of the tubes of A. adspersa were assessed via imaging analysis. In addition, morphological diagnostic analyses were carried out on some sampled specimens and on their tubes. The acquired data shed new light on how polychaetes can exploit the dead tissues of P. oceanica, contributing to highlight interactions between benthic fauna and seagrass detritus in the marine environment and their ecological role in enhancing the spatial heterogeneity of soft areas of the Mediterranean seafloor. [ABSTRACT FROM AUTHOR]

The character of pure or mixed forest canopies and their litterfalls contribute to different forest-floor properties. These organic layers and also subjacent topsoil were studied at three study sites covered by mixed treatments such as beech–spruce, beech–fir, spruce–fir and two monospecific beech and spruce treatments. The age of the forest stands ranged from 11 to 15 years when sampled. All study sites were used as meadows when afforested; therefore, the forest floors were new, and the A-horizon topsoil properties were not influenced by older humus inherited from previous forest generations. The mineral soil was likely affected by different levels of former fertilization, which resulted in differences among the study sites. The early-developed forest floors showed differences between the treatments with beech and the others. The topsoil below beech with spruce had more nitrogen, oxidizable carbon and cations of exchangeable hydrogen as well as pH showing more acidic conditions and lower contents and saturation of base cations. Pure beech had more phosphorus. The nutrient pools did not differ among the treatments; significantly more matter was found below the oldest stands on the first afforested site, which also increased nutrient pools. [ABSTRACT FROM AUTHOR]

The general practice of sheep farmers in gastrointestinal helminth control is based on the use of commercial drugs, making chemoresistance very common. Considering this, our study focused on the biological control of gastrointestinal parasitism using high-tannin plant hay. Three groups of 30 animals each were formed. The control group was additionally fed meadow hay, while the other two groups received chicory (group 2) and bird's foot trefoil hay (group 3). The number of gastrointestinal strongyle eggs, shed through faeces (EPG), was surveyed for 28 days for all animals. The amounts of total tannins for meadow, chicory, and Lotus corniculatus hay supplements were 13.92 mg/g, 78.59 mg/g, and 94.43 mg/g, while their condensed tannin contents were 2.58 mg/g, 29.84 mg/g, and 15.94 mg/g, respectively. Compared to experimental day 0, there was an increase in EPG of 80.83% in the control group, a decrease of 24.72% in group 2, and a 20% decrease in group 3, by day 28. The p-value was <0.05 between group 1 and the other groups, showing significant differences between the control and experimental groups. The decrease in EPG rates in the experimental groups compared to the control group demonstrates an antiparasitic effect of Lotus corniculatus and chicory. [ABSTRACT FROM AUTHOR]

Adaptation to local conditions is known to occur in seagrasses; however, knowledge of the genetic basis underlying this phenomenon remains scarce. Here, we analysed Posidonia oceanica from six sites within and around the Stagnone di Marsala, a semi‐enclosed coastal lagoon where salinity and temperature exceed the generally described tolerance thresholds of the species. Sea surface temperatures (SSTs) were measured and plant samples were collected for the assessment of morphology, flowering rate and for screening genome‐wide polymorphisms using double digest restriction‐site‐associated DNA sequencing. Results demonstrated more extreme SSTs and salinity levels inside the lagoon than the outer lagoon regions. Morphological results showed significantly fewer and shorter leaves and reduced rhizome growth of P. oceanica from the inner lagoon and past flowering events were recorded only for a meadow farthest away from the lagoon. Using an array of 51,329 single nucleotide polymorphisms, we revealed a clear genetic structure among the study sites and confirmed the genetic isolation and high clonality of the innermost site. In all, 14 outlier loci were identified and annotated with several proteins including those relate to plant stress response, protein transport and regulators of plant‐specific developmental events. Especially, five outlier loci showed maximum allele frequency at the innermost site, likely reflecting adaptation to the extreme temperature and salinity regimes, possibly due to the selection of more resistant genotypes and the progressive restriction of gene flow. Overall, this study helps us to disentangle the genetic basis of seagrass adaptation to local environmental conditions and may support future works on assisted evolution in seagrasses. [ABSTRACT FROM AUTHOR]

Habitat loss is accelerating at unprecedented rates, leading to the emergence of smaller, more isolated habitat remnants. Habitat isolation adversely affects many ecological processes independently, but little is known about how habitat isolation may interact with ecosystem processes such as top-down (consumer-driven) and bottom-up (resource-driven) effects. To investigate the interactive influence of habitat isolation, resource availability and consumer distribution and impact on community structure, we tested two hypotheses using invertebrate and algal epibionts on temperate seagrasses, an ecosystem of ecological and conservation importance. First, we hypothesized that habitat isolation will change the structure of the seagrass epibiont community, and isolated patches of seagrass will have lower epibiont biomass and different epibiont community composition than contiguous meadows. Second, we hypothesized that habitat isolation would mediate top-down (i.e., herbivory) and bottom-up (i.e., nutrient enrichment) control for algal epibionts. We used observational studies in natural seagrass patches and experimental artificial seagrass to examine three levels of habitat isolation. We further manipulated top-down and bottom-up processes in artificial seagrass through consumer reductions and nutrient additions, respectively. We indeed found that habitat isolation of seagrass patches decreased epibiont biomass and modified epibiont community composition. This pattern was largely due to dispersal limitation of invertebrate epibionts that resulted in a decline in their abundance and richness in isolated patches. Further, habitat isolation reduced consumer abundances, weakening top-down control of algal epibionts in isolated seagrass patches. Nutrient additions, however, reversed this pattern, and allowed a top-down effect on algal richness to emerge in isolated habitats, demonstrating a complex interaction between patch isolation and top-down and bottom-up processes. Habitat isolation may therefore shape the relative importance of central processes in ecosystems, leading to changes in community composition and food web structure in marine habitats. [ABSTRACT FROM AUTHOR]

The present work was performed to evaluate the levels of phytochemical constituents and the antioxidant and antibacterial properties of marine red seaweed (Kappaphycus alvarezii) and seagrass (Cymodocea serrulata). Quantitative phytochemical analysis, antioxidant activity and antimicrobial activity against five potential pathogenic bacteria was investigated. In each case, we found the presence of flavonoids, tannins, phenolic compounds, glycosides, steroids, carbohydrates and ashes. Alkaloids were only found in K. alvarezii, though they were not found in C. serrulata. The antimicrobial properties of both K. alvarezii and C. serrulata chloroform extracts were found to be antagonistically effective against the Gram-positive bacteria Bacillus subtilis and the Gram-negative bacteria Vibrio parahaemolyticus, Vibrio alginolyticus, Vibrio harveyi and Klebsiella pneumoniae. GC-MS analysis revealed the presence of 94 bioactive compounds in K. alvarezii and 104 bioactive compounds in C. serrulata, including phenol, decane, dodecane, hexadecane, vanillin, heptadecane, diphenylamine, benzophenone, octadecanoic acid, dotriaconate, benzene, phytol, butanoic acid and 2-hydroxyl-ethyl ether, which all played important roles in antioxidant and antibacterial activities. Thus, in view of the results, both K. alvarezii and C. serrulata could be considered to be sources of ingredients with appreciable nutritional and medicinal value. [ABSTRACT FROM AUTHOR]

Marine heatwaves (MHWs) are a growing threat to marine species globally, including economically and ecologically important foundation species, such as seagrasses. Seagrasses in tropical regions may already be near their thermal maxima, and, therefore, particularly susceptible to increases in temperature, such as from MHWs. Here, we conducted a 10‐day MHW experiment (control +4°C) to determine the effects of such events on the two tropical seagrasses Halophila beccarii and Halophila ovalis. We found that both species were largely resistant to the MHW, however, there were differences between the species' responses. For H. beccarii, the surface area of existing leaves was smaller under MHW conditions, yet a substantial increase in the number of new leaves under the MHW indicated its tolerance to—or even increased performance under—the MHW. While there was no direct effect of the MHW on H. ovalis, this species saw less epiphyte biomass and percentage cover on its leaves under the MHW. While a lower epiphyte cover can potentially increase the health and ecophysiological performance of the seagrass, the change of epiphytes can lead to bottom‐up trophic implications via the influence on mesograzer feeding. Together, the results of this study demonstrate the species‐specific responses of seagrasses of the same genus to a warming event. With the current global decline of seagrasses, our results are encouraging for these important habitat formers as we show that anomalous warming events may not necessarily lead to ecosystem collapse. [ABSTRACT FROM AUTHOR]

The study of microfacies, with special emphasis on the significance of larger benthic foraminifera, is used to interpret the occurrence of different marine subenvironments into a mixed carbonate-siliciclastic platform from the upper Campanian in the Prebetic domain, representing the southeastern margin of the Cretaceous Iberian paleoisland. Four foraminiferal assemblages have been recognized, each one specifically assigned to a depositional systems: (1) the outer to middle shelf with Neorotalia? pinetensis, Goupillaudina spp., gavelinellids, Orbitoides tissoti-media, Praesiderolites douvillei, and Navarella joaquini; (2) the upper part of the middle shelf with the presence of seagrass meadows Orbitoides tissoti-media, "Orbitoides" concavatus, Lepidorbitoides campaniensis, Planorbulina cretae, Sirtina ornata, Praesiderolites douvillei, Pseudosiderolites vidali, and Rotalia baetica; (3) the upper photic zone of the inner shelf, with constant wave agitation, inhabited by Orbitoides cf. megaloformis, Lepidorbitoides campaniensis, and Wannierina vilavellensis; and (4) the paralic shallow protected shelf with alternating marine/freshwater influences characterized by charophytes and Suturina minima. Results on larger foraminifera distribution show the similarities and differences with the benthic communities shallow water platform assemblages of the nearby Pyrenean paleobioprovince. This allows to rise the Upper Cretaceous shelfs of the Betic area as a fundamental biogeographic piece for larger benthic foraminifera migration patterns between the Tethyan domain and the other marine domains during the Late Cretaceous. [ABSTRACT FROM AUTHOR]

Soil and water resources represent some of the great wealth with which nature has endowed our planet. The purpose of the paper is the study of these resources (soil and water), from Zăvoi commune, Caraș Severin county, considering the recent climate changes, which tend to negatively influence this area as well, with repercussions on the entire evolution plant development. The health of the soil and the purity of the water are essential to be able to talk about the quality of life, environmental factors (soil, water, climate, air, etc.) can influence the well-being and health of people. For the preparation of the paper, data obtained both from observations in the field and data taken from previous researches, including OSPA Caraș Severin, were used. The town of Zăvoi has a total area of 39600 ha, of which 53.66% (21249 ha) are agricultural land and 43.30%, i.e. 17145 ha, is forest. The diversity of the relief units made the area divided: the area of the hills, where luvosol and eutricambosol soils are found and which offer the possibility of a more varied agriculture and obtaining large productions; the hilly floor, which includes a mixed agricultural area, thanks to various soils, represented by regosols, lithosols, districambosols, prepodzols and antrosols, here the largest area of land is forested and the meadow area, where we find alluvial soils, along with stagnosols and gleosols, the most common being soils with excess phreatic moisture and requiring drainage improvement works. In this area, a number of plants are cultivated such as: wheat, corn, sunflower, oats, orzoaica, up to vegetables, potatoes and beets. The general capacity of these soils in terms of agricultural production capacity is medium. [ABSTRACT FROM AUTHOR]

Seagrasses are marine flowering plants, which form extensive meadows in intertidal and shallow water marine environments. They provide a wide range of ecosystem services, which directly or indirectly benefit humans and can be grouped into four broad categories: provisioning (e.g. food production); regulating (e.g. carbon sequestration); supporting (e.g. primary production); and cultural (e.g. recreational, and eco-tourism). This study provides a review of publications focusing on seagrass ecosystem services provision to identify knowledge gaps and improve our understanding of the use of these habitats as nature-based solutions to societal challenges, such as climate change. Results showed that some ecosystem services, namely food provision, carbon sequestration, and maintenance of biodiversity/nursery habitats receive a higher level of focus and attention than others, such as regulation of diseases and social relations, which are rarely, if ever, included in studies. It is clear that in order to fully comprehend the nature-based solution potential held by seagrass ecosystems, studies need to consider ecosystem services as a whole, and also combine and share results across global regions, to better understand the potential impacts of degradation and loss of these ecosystems worldwide. Suggestions include applying novel technologies such as remote sensing and ecological niche modelling to address some of the main gaps in seagrass research, like meadow extent and connectivity within landscapes, to better incorporate preservation of seagrass ecosystems in marine management plans. [ABSTRACT FROM AUTHOR]

Seagrass meadows provide diverse ecosystem services that directly or indirectly benefit the coastal communities. Despite this, they are among the most threatened coastal ecosystems. Though coastal and marine conservation actions have progressed over the years, seagrasses received less attention compared with other more charismatic ecosystems such as coral reefs and mangroves. Among the influencing factors, the lack of societal recognition of what seagrasses are and their importance underlies the global crisis of seagrass conservation. Thus, in this study, we gathered rural and urban perceptions of seagrass ecosystem services, their threats, and management‐related activities at the unit of barangay or village in the Philippines. Overall, rural respondents displayed higher awareness of seagrass ecosystem services than urban respondents. Socio‐economic status and personal connection or direct experience to these services influenced their perceptions. Local‐level threats were also perceived and recognizing these at the early onset can avoid severe habitat degradation. Though the role of seagrass blue carbon in climate change mitigation was barely discussed in local contexts, the impact of climate change‐induced stressors on seagrass was perceived by the respondents. Thus, local stakeholders, practitioners, and policymakers have the opportunity to design future seagrass‐focused management plans and programs in the era of climate change. [ABSTRACT FROM AUTHOR]

The sea urchin Tripneustes gratilla is a major grazer and is, hence, an excellent key model organism to study to gain a better understanding of responses to changes in its habitat. We investigated whether there are significant variations in the feeding and reproductive phenotypic traits of populations from three seagrass bed sites, with respect to their proximity to fish farms in Bolinao, northwestern Philippines. We established three stations in each of the three sites: the far, the intermediate, and those near the fish farms, and compared the sea urchins' phenotypic traits and determined whether these were related to seagrass productivity and water parameters. Regardless of the sampling period, adult sea urchins (66.92 ± 0.27 mm test diameter, TD, n = 157) from the areas intermediate and near to the fish farms had significantly lower indices of Aristotle's lantern, gut contents, gut and gonads, and lower gonad quality (high percentage of unusual black gonads), compared to those from the far stations. Multivariate analysis showed that the smaller feeding structures and gut, lower consumption rates and lower gonad indices and quality of sea urchins in the intermediate and near fish farms were positively related to lower shoot density, leaf production and species diversity, as well as lower water movement in those stations. The larger size of the Aristotle's lantern in the far stations was not related to food limitations. More importantly, the phenotypic variability in the feeding structures and gonads of sea urchins in the same seagrass bed provides new evidence regarding the sensitivity of this species to environmental factors that may affect variability in food quality. [ABSTRACT FROM AUTHOR]

Konservat‐Lagerstätten, such as the Toarcian (Early Jurassic) Posidonia Shale of southwestern Germany, are renowned for their spectacular fossils. Ichthyosaur skeletons recovered from this formation are frequently associated with soft tissues; however, the preserved material ranges from three‐dimensional, predominantly phosphatized structures to dark films of mainly organic matter. We examined soft‐tissue residues obtained from two ichthyosaur specimens using an integrated ultrastructural and geochemical approach. Our analyses revealed that the superficially‐looking 'films' in fact comprise sections of densely aggregated melanosome (pigment) organelles sandwiched between phosphatized layers containing fibrous microstructures. We interpret this distinct layering as representing condensed and incompletely degraded integument from both sides of the animal. When compared against previously documented ichthyosaur fossils, it becomes readily apparent that a range of preservational modes exists between presumed 'phosphatic' and 'carbonized' soft‐tissue remains. Some specimens show high structural fidelity (e.g. distinct integumentary layering), while others, including the fossils examined in this study, retain few original anatomical details. This diversity of soft‐tissue preservational modes among Posidonia Shale ichthyosaurs offers a unique opportunity to examine different biostratinomic, taphonomic and diagenetic variables that potentially could affect the process of fossilization. It is likely that soft‐tissue preservation in the Posidonia Shale was regulated by a multitude of factors, including decay efficiency and speed of phosphatic mineral nucleation; these in turn were governed by a seafloor with sustained microbial mat activity fuelled by high organic matter input and seasonally fluctuating oxygen levels. [ABSTRACT FROM AUTHOR]

Fuentes-Agueda, S.A.; Gallegos, M.E.; Mandujano, M.C., and Golubov, J., 2023. Contrasting growth and establishment of Thalassia testudinum along a cover gradient in the Gulf of Mexico. Journal of Coastal Research, 39(4), 653–662. Charlotte (North Carolina), ISSN 0749-0208. Seagrasses are important for coastal ecosystem health and have significant economic benefits; however, they are undergoing important negative changes worldwide. The seagrass Thalassia testudinum comprises one of the main elements in submerged aquatic vegetation (SAV) habitats, and it grows in monospecific and mixed meadows along the continental shelf of the Gulf of Mexico. In this study, T. testudinum monospecific and mixed meadows were monitored over a 2 year period to identify the abiotic and biotic conditions that may correlate with population parameters through the plastochron index (PI). Plants found in monospecific meadows had larger rhizomes and more flowers in comparison to those in mixed meadows, while the latter produced more leaves and larger shoots. The annual rate of change in biomass (Br) of T. testudinum in the monospecific meadow was 1.15 ± 0.03, which was slightly higher than that in the mixed meadow, with a value of 1.12 ± 0.03. T. testudinum in monospecific meadows tended to exhibit increased sexual reproduction, while vegetative growth and clonal reproduction were more common in mixed meadows. The results highlight that T. testudinum life-history strategies and establishment are affected by both biotic and abiotic factors like depth, temperature, and water nutrients. [ABSTRACT FROM AUTHOR]

The restoration of seagrass habitats is a relatively young field with several successful restoration attempts highlighting the feasibility of large‐scale restoration. Successful restoration of seagrass habitats requires an understanding of the most appropriate techniques to use for the target species and local conditions of restoration sites, however, there are currently limited studies on Zostera muelleri. Here, we conduct field trials to explore the use of seed‐ and shoot‐based restoration approaches for Z. muelleri in Victoria, Australia. We assessed the feasibility of collecting and germinating seeds in the field for restoration purposes and trialed the success of four shoot‐based transplanting techniques. We found that seed collections for Z. muelleri were highly successful and scalable, with seed collection rates improving from 489 to 1,939 seeds/hour over 2 years. In addition, in situ seedling germination increased from a maximum of 10.80–25.25% over 2 years. In contrast, shoot‐based restoration approaches were more variable, with plants transplanted with their sediment‐intact outperforming all bare‐rooted approaches. Shoot‐based transplanting approaches appear to have more limited application, but may be appropriate for some restoration sites, or used in combination with seeds to achieve the best restoration outcome. Seed‐based approaches have the potential to be viable and scalable for Z. muelleri given that large numbers of seeds can be collected and stored for at least 7 months before successfully germinating in the field. However, further studies are required to overcome the seedling survival bottleneck (approximately 4 months from emergence) and further increase in situ germination rates. [ABSTRACT FROM AUTHOR]

Restoration is an important activity to assist the recovery of damaged or degraded ecosystems. Accessing healthy donor material can be challenging when restoring threatened ecological communities, but careful selection of donor material may improve the success and cost‐effectiveness of restoration projects. We aim to optimize restoration of the threatened seagrass Posidonia australis by identifying the traits of donor material that best predict survival and establishment. To avoid collecting donor material from threatened populations, a recent restoration method focuses on using naturally detached fragments of P. australis collected from the shoreline, which are stored in outdoor tanks prior to planting. Here, we examine 10 morphological traits of P. australis fragments and other variables relating to collection method to identify which traits best predicted survival after replanting. Fragments with more shoots and less dead tissue (necrosis) in their leaves had higher survival 1 year after planting. Fragments that were stored longer in tanks prior to replanting had significantly higher survival rates. These results can refine the selection for donor material used in restoration and optimize the recently developed restoration technique for P. australis using beach‐cast seagrass material. [ABSTRACT FROM AUTHOR]

The organic carbon (Corg) stored in seagrass meadows is globally significant and could be relevant in strategies to mitigate increasing CO2 concentration in the atmosphere. Most of that stored Corg is in the soils that underlie the seagrasses. We explored how seagrass and soil characteristics vary among seagrass meadows across the geographic range of turtlegrass (Thalassia testudinum) with a goal of illuminating the processes controlling soil organic carbon (Corg) storage spanning 23° of latitude. Seagrass abundance (percent cover, biomass, and canopy height) varied by over an order of magnitude across sites, and we found high variability in soil characteristics, with Corg ranging from 0.08 to 12.59% dry weight. Seagrass abundance was a good predictor of the Corg stocks in surficial soils, and the relative importance of seagrass-derived soil Corg increased as abundance increased. These relationships suggest that first-order estimates of surficial soil Corg stocks can be made by measuring seagrass abundance and applying a linear transfer function. The relative availability of the nutrients N and P to support plant growth was also correlated with soil Corg stocks. Stocks were lower at N-limited sites than at P-limited ones, but the importance of seagrass-derived organic matter to soil Corg stocks was not a function of nutrient limitation status. This finding seemed at odds with our observation that labile standard substrates decomposed more slowly at N-limited than at P-limited sites, since even though decomposition rates were 55% lower at N-limited sites, less Corg was accumulating in the soils. The dependence of Corg stocks and decomposition rates on nutrient availability suggests that eutrophication is likely to exert a strong influence on carbon storage in seagrass meadows. [ABSTRACT FROM AUTHOR]

Vegetation and its spatiotemporal variations play a crucial role in regional ecological security and sustainable development. Examining vegetation dynamics in natural reserves provides valuable insights for optimizing vegetation patterns and management strategies. This study utilizes Landsat remote sensing imagery to investigate changes in vegetation pattern and coverage in the Cangshan mountain of the Cangshan Erhai National Nature Reserve, as well as assesses the effectiveness of conservation efforts. The results indicate the following: (1) The primary vegetation types in the Cangshan mountain include warm-temperate coniferous forests, deciduous broad-leaved forests, bamboo forests, and alpine meadows, exhibiting distinct vertical zonation patterns. The vegetated area expanded by 1146 hectares during the study period. (2) The average fractional of vegetation coverage (FVC) in the Cangshan mountain demonstrated an upward trend (0.82 in 1987 to 0.93 in 2017), with the proportion of highly FVC areas increasing from 59.67% in 1987 to 97.89% in 2017. (3) The vegetation landscape fragmentation in Cangshan mountain and various functional areas shows an increasing trend, while connectivity decreases, and is accompanied by a more intricate shape of the vegetation landscape. While conservation and management efforts have yielded certain results in safeguarding the vegetation in the Cangshan mountain, the degree of vegetation landscape fragmentation has intensified due to climate change and human activities. Thus, it is imperative for management authorities to promptly adjust protective measures within the Cangshan mountain. This study contributes to our understanding of vegetation changes within the Cangshan mountain and provides essential baseline information for optimizing and enhancing vegetation conservation management strategies within the reserve. [ABSTRACT FROM AUTHOR]

Bojonegara District, having a strategic location in the coastal area of Banten Bay, is undergoing rapid industrial development. The economic activities in coastal areas simultaneously increase the ecological pressure on ecosystems and coastal resources. Ecosystem stress, directly and indirectly, disrupts organisms' life on land and in waters, causing physical, chemical, and biological changes in coastal areas of Bojonegoro District to Lima Island, causing a potential impact on socio-anthropogenic activities. This research uses a mixed qualitative and quantitative approach through observational data and literature review to estimate the economic loss that occurs if one element in the coastal area is disturbed, impacting the whole system. The water sample was collected at fifteen spots, including industrial, port, and monitoring stations along the coastal areas of Bojonegoro District to Lima Island, to assess the severity of the impacts of industrial pollution. Total economic loss is calculated using the productivity and replacement cost approach to analyze the loss value of damage on three seagrass ecosystem functions. The total loss value due to damage is estimated to be more than IDR. 950 million per year. This study finds the high economic loss is due to the low level of public knowledge and awareness, as only ≤19% of the research respondents recognize the types of ecosystem variations in coastal areas, their existence, current conditions, and utilization. This study also finds that the industry still commits environmental violations in various cases, which the stakeholders must resolve to avoid further environmental damage. [ABSTRACT FROM AUTHOR]