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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.

Climate change is altering species’ range limits and transforming ecosystems. For example, warming temperatures are leading to the range expansion of tropical, cold-sensitive species at the expense of their cold-tolerant counterparts. In some temperate and subtropical coastal wetlands, warming winters are enabling mangrove forest encroachment into salt marsh, which is a major regime shift that has significant ecological and societal ramifications. Here, we synthesized existing data and expert knowledge to assess the distribution of mangroves near rapidly changing range limits in the southeastern USA. We used expert elicitation to identify data limitations and highlight knowledge gaps for advancing understanding of past, current, and future range dynamics. Mangroves near poleward range limits are often shorter, wider, and more shrublike compared to their tropical counterparts that grow as tall forests in freeze-free, resource-rich environments. The northern range limits of mangroves in the southeastern USA are particularly dynamic and climate sensitive due to abundance of suitable coastal wetland habitat and the exposure of mangroves to winter temperature extremes that are much colder than comparable range limits on other continents. Thus, there is need for methodological refinements and improved spatiotemporal data regarding changes in mangrove structure and abundance near northern range limits in the southeastern USA. Advancing understanding of rapidly changing range limits is critical for foundation plant species such as mangroves, as it provides a basis for anticipating and preparing for the cascading effects of climate-induced species redistribution on ecosystems and the human communities that depend on their ecosystem services.

Climate change is transforming ecosystems and affecting ecosystem goods and services. Along the Gulf of Mexico and Atlantic coasts of the southeastern United States, the frequency and intensity of extreme freeze events greatly influence whether coastal wetlands are dominated by freeze-sensitive woody plants (mangrove forests) or freeze-tolerant grass-like plants (salt marshes). In response to warming winters, mangroves have been expanding and displacing salt marshes at varying degrees of severity in parts of north Florida, Louisiana, and Texas. As winter warming accelerates, mangrove range expansion is expected to increasingly modify wetland ecosystem structure and function. Because there are differences in the ecological and societal benefits that salt marshes and mangroves provide, coastal environmental managers are challenged to anticipate the effects of mangrove expansion on critical wetland ecosystem services, including those related to carbon sequestration, wildlife habitat, storm protection, erosion reduction, water purification, fisheries support, and recreation. Mangrove range expansion may also affect wetland stability in the face of extreme climatic events and rising sea levels. Here, we review the current understanding of the effects of mangrove range expansion and displacement of salt marshes on wetland ecosystem services in the southeastern United States. We also identify critical knowledge gaps and emerging research needs regarding the ecological and societal implications of salt marsh displacement by expanding mangrove forests. One consistent theme throughout our review is that there are ecological trade-offs for consideration by coastal managers. Mangrove expansion and marsh displacement can produce beneficial changes in some ecosystem services, while simultaneously producing detrimental changes in other services. Thus, there can be local-scale differences in perceptions of the impacts of mangrove expansion into salt marshes. For very specific local reasons, some individuals may see mangrove expansion as a positive change to be embraced, while others may see mangrove expansion as a negative change to be constrained.

This study sought to examine the impact of nodule density on recurrence and survival in female patients with lung adenocarcinoma treated by lobectomy or sublobar resection.In this retrospective study of female patients who underwent surgical resection for pathologic stage IA adenocarcinoma, patients with preoperative imaging were included for analysis if the consolidation-to-tumor ratio was 0.5 (solid-predominant ground-glass opacity [GGO]) to 1.0 (solid). Kaplan-Meier curves were generated to estimate overall survival (OS) and disease-free survival (DFS). Risk estimates were calculated using multivariable Cox proportional hazards models.For all 357 patients sublobar resection demonstrated worse 5-year DFS compared with lobectomy (76.4% vs 67.9%, P = .05). Multivariable modeling showed worse DFS with sublobar resection (hazard ratio, 1.55; P = .06) and tumors ≥ 2 cm (hazard ratio, 2.32; P = .05). On radiologic evaluation the solid-predominant GGO group (n = 81) demonstrated a smaller solid component compared with the solid nodule group (n = 163; 1.49 cm vs. 1.84 cm, respectively; P.001) yet comparable total size. The solid-predominant GGO group showed improved 5-year OS (90.8 vs 76.8, P = .01) and DFS (79.3 vs 67.2, P = .05) compared with the solid nodule group. Additionally the solid-predominant GGO group demonstrated equivalent OS (90.8% vs 90.8%, P = .93) and DFS (76.0% vs 81.7%, P = .60) with sublobar resection compared with lobectomy.In this report of female patients with stage IA adenocarcinoma, sublobar resection was associated with worse DFS compared with lobectomy in whole-group analysis. However patients with solid-predominant GGOs demonstrated improved 5-year OS and DFS compared with patients with solid nodules with equivalent outcomes regardless of resection type.

Black mangroves Avicennia germinans are becoming increasingly common in coastal wetlands in the Gulf of Mexico (USA). As mangroves displace salt marsh vegetation, there may be consequences for associated wetland fauna. In a series of field studies, we compared prey refuge values between marsh and mangrove vegetation for a vertically migrating gastropod, the marsh periwinkle Littoraria irrorata. Littoraria were tethered to marsh grasses (Spartina alterniflora) or the aerial roots (pneumatophores) of Avicennia in arrays that fully crossed vegetation type (Spartina vs. Avicennia), tether height (base vs. canopy), and wetland location (edge vs. interior marsh platform). After 1 d, acute predation rates were twice as high on Littoraria tethered to the base of Spartina stems than on those tethered to pneumatophores, suggesting that mangroves provided superior refuge from benthic predators like blue crabs. In the canopy, Spartina reduced acute predation rates by 75%, indicating that marsh grasses may provide superior refuge from aerial predators (possibly wetland birds). After 7 d, the effect of vegetation type diminished, but Littoraria mortality was 2 times higher on the benthos than in the canopy. Links between vegetation type and predation intensity on this important basal consumer may have broader consequences for trophic dynamics in coastal wetlands that are experiencing mangrove encroachment.

Studies of competition in mangroves are mostly limited to seedlings and artificial settings like forestry projects. We conducted the first experimental study of intraspecific competition among adult mangroves in a natural mangrove forest to examine how important competition is in determining tree size compared with abiotic conditions. We conducted a study near Port Aransas, TX, USA, which is near the geographical limit of mangroves and dominated by monospecific stands of ‘scrub’ form black mangroves, Avicennia germinans. We thinned 10 plots to create a gradient of mangrove cover, and quantified the effects of mangrove cover on the growth of tagged mangroves from 2013 to 2019, and the mangrove canopy height in 2019. The relative growth rate of tagged mangroves declined as mangrove cover increased, and plants in the plot with 100% mangrove cover did not grow, indicating that they had attained their maximum size. In plots with reduced mangrove cover, plant height increased sharply, with plants in the plot with 11% mangrove cover growing ~52% taller over 6 years. Canopy height was ~30% taller in the plot fringe than in the interior, and canopy height in both fringe and interior declined as mangrove cover increased. Measures of leaf chlorophyll concentration and light interception suggested that plants were primarily limited by nitrogen. Our results showed that scrub mangroves compete strongly despite being limited by abiotic conditions, and that the importance of competition was greater in magnitude than that of abiotic differences between the fringe and interior.

Ecologists use multiple methods for studying interspecific competition, but different approaches may give different answers. We compared four methods to quantify the competitive interactions between Avicennia germinans (black mangroves) and salt marsh vegetation in Texas, USA: two different methods of sampling a large (24 x 42 m) mangrove removal experiment, a transplant experiment conducted within the large experiment, and an observational study comparing sites naturally dominated by marsh or mangrove vegetation. As expected, mangroves strongly suppressed the cover and biomass of salt marsh plants. But our understanding of the strength of these interactions varied depending on the study method used, the plant species studied, and the spatial scale considered; different processes influencing community assembly. The transplant experiment isolated the effects of competition driven only by the presence or absence of mangroves in the immediate (3x3 m plot) vicinity of the transplanted plants. In contrast, the observational study examined the combined effects of dispersal, abiotic suitability and competition as a function of the cover of mangroves at the larger plot scale. Combining the approaches in areas with levels of mangrove cover varying from 45% to 97% provided insight into how results from the local scale could be extrapolated to the landscape. Although mangroves may compete strongly with neighboring marsh plants growing in their immediate vicinity, marsh plants may not be totally eradicated from sites colonized by mangroves, but instead may persist on the landscape at low densities in stressful habitats that offer a refuge from competition.

When restoring coastal wetlands, approaches can vary in construction technique, planting strategy, and site placement within an anthropogenically altered landscape comprising both relict wetlands and developed habitat. Constructed marshes are often composed of discrete terraces or mounds formed with excavated sediments, or beneficial uses (BU) dredge material can be used to fill continuous areas to emergent marsh elevation. Either construction approach can be seeded or planted with native species, or colonization can occur naturally. Sites can vary in the degree of hydrological isolation due to the presence of structures (e.g., roads or buildings) that limit connectivity to other marsh areas. Data collected across multiple sites on the upper Texas (USA) coast were used to assess how coastal wetland restoration “success,” measured as emergent plant cover, biomass, and species richness, was influenced by the localized configuration of individual restoration sites and by the placement of each site within a landscape matrix of reference wetlands and developed areas. Plant biomass and cover in BU marshes were similar to reference conditions and up to 70% higher than in excavated formations, regardless of planting technique or location in the landscape. Species richness was highest at the reference sites and lowest at planted beneficial uses sites, but none of the restoration sites had species assemblages similar to reference areas. Restoration outcomes were relatively robust to anthropogenic alterations of the landscape. Individual restoration sites were highly dissimilar from each other, and although some had very low (

As global change alters the composition and productivity of ecosystems, the importance of subsidies from one habitat to another may change. We experimentally manipulated black mangrove (Avicennia germinans) cover in 10 large plots and over a 5-year period (2014-2019) quantifying the effects of mangrove cover on subsidies of floating organic material (wrack) into coastal wetlands. As mangrove cover increased from 0% to 100%, wrack cover and thickness decreased by ~60%, the distance that wrack penetrated into the plots decreased by ~70%, and the percentage of the wrack trapped in the first 6 m of the plot tripled. These patterns observed during 4 "normal" years disappeared in a fifth year following Hurricane Harvey (2017), when large quantities of wrack were pushed far into the interior of all the plots, regardless of mangrove cover. Prior to the storm, the abundance of animals collected in grab samples increased with wrack biomass. Wrack composition did not affect animal abundance or composition. Experimental outplants of two types of wrack (red algae and seagrass) revealed that animal abundance and species composition varied between the fringe and interior of the plots, and between microhabitats dominated by salt marsh versus mangrove vegetation. The importance of wrack to overall carbon stocks varied as a function of autochthonous productivity: wrack inputs (per m

Tropical cyclones are major disturbances for coastal systems. Hurricane Harvey made landfall in Texas, USA, on August 25, 2017 as a category 4 storm. There were two distinct disturbances associated with this storm that were spatially decoupled: (1) high winds causing direct damage and storm surge, and (2) high rains causing scouring floods and significant discharge of fresh water carrying carbon and nutrients to estuaries. Here, we provide a synthesis of the effects of Hurricane Harvey on biogeochemical, hydrographic, and biotic components of freshwater and estuarine systems and their comparative resistance and resilience to wind- and rain-driven disturbances. Wind-driven disturbances were most severe along the coastal barrier islands and lower estuaries, damaging mangroves and seagrass and increasing sediment coarseness. Rain-driven disturbances were most pronounced within freshwater streams and the upper estuaries. Large volumes of freshwater run-off reduced the abundance of riverine fauna and caused hypoxic and hyposaline conditions in the estuaries for over a week. In response to this freshwater input event, benthic fauna diversity and abundance decreased, but mobile fauna such as estuarine fishes did not markedly change. Although hydrographic and biogeochemical components were highly perturbed, they returned to baseline conditions within days. In contrast, biotic components demonstrated lower magnitude changes, but some of these organisms, particularly the sedentary flora and fauna, required weeks to months to return to pre-storm conditions, and some did not recover within the 6 months reported here. Our synthesis illustrates that resistance and resilience of system components may negatively co-vary and that structural components of coastal systems may be the most vulnerable to long-term changes following tropical cyclones.

Near the tropical‐temperate transition zone, warming winter temperatures are expected to facilitate the poleward range expansion of freeze‐sensitive tropical organisms. In coastal wetlands of eastern and central North America, freeze‐sensitive woody plants (mangroves) are expected to expand northward into regions currently dominated by freeze‐tolerant herbaceous salt marsh plants. To advance understanding of mangrove range expansion, there is a need to refine temperature thresholds for mangrove freeze damage, mortality and recovery. We integrated data from 38 sites spread across the mangrove range edge in the Gulf of Mexico and Atlantic coasts of North America, including data from a regional collaborative network – the Mangrove Migration Network. In 2018, an extreme freeze event affected 60% of these sites, with minimum temperatures ranging from 0 to −7°C. We used temperature and vegetation data from before and after the freeze to quantify temperature thresholds for leaf damage, mortality and biomass recovery of the black mangrove (Avicennia germinans) – the most freeze‐tolerant mangrove species in North America. For A. germinans individuals near their northern range limit, our results indicate that temperature thresholds for leaf damage are close to −4°C, but temperature thresholds for mortality are closer to −7°C. Thresholds are expected to be warmer for more southern A. germinans individuals and for the other two common mangrove species in the region (Laguncularia racemosa and Rhizophora mangle). Regenerative buds allowed A. germinans to resprout and recover quickly from above‐ground freeze damage. Hence, biomass recovery levels during the first post‐freeze growing season were 90%, 78%, 62% and 45% for temperatures of −4, −5, −6 and −7°C, respectively. Due to a combination of vigorous resprouting and new recruitment from propagules, we expect full recovery at most sites within 1–3 years, assuming no further freeze events. Synthesis. To improve predictions of tropical range expansion in response to climate change, there is a need to better understand tropical species’ responses to winter temperature extremes. Collectively, our results refine temperature thresholds for A. germinans freeze damage, mortality and recovery, which can improve predictions of mangrove range expansion and coastal wetland ecological transformations in a warming climate.

The capacity of coastal wetlands to stabilize shorelines and reduce erosion is a critical ecosystem service, and it is uncertain how changes in dominant vegetation may affect coastal protection. As part of a long-term study (2012–present) comparing ecosystem functions of marsh and black mangrove vegetation, we have experimentally maintained marsh and black mangrove patches (3 m × 3 m) along a plot-level (24 m × 42 m) gradient of marsh and mangrove cover in coastal wetlands near Port Aransas, TX. In August 2017, this experiment was directly in the path of Hurricane Harvey, a category 4 storm. This extreme disturbance event provided an opportunity to quantify differences in resistance between mangrove and marsh vegetation and to assess which vegetation type provided better shoreline protection against storm-driven erosion. We compared changes in plant cover, shoreline erosion, and accreted soil depth to values measured prior to storm landfall. Relative mangrove cover decreased 25–40% after the storm, regardless of initial cover, largely due to damage on taller mangroves (> 2.5 m height) that were not fully inundated by storm surge and were therefore exposed to strong winds. Evidence of regrowth on damaged mangrove branches was apparent within 2 months of landfall. Hurricane-induced decreases in mangrove cover were partially ameliorated by the presence of neighboring mangroves, particularly closer to the shoreline. Marsh plants were generally resistant to hurricane effects. Shoreline erosion exceeded 5 m where mangroves were absent (100% marsh cover) but was relatively modest (

We tested the hypothesis that mangroves provide better coastal protection than salt marsh vegetation using ten 1,008 m2 plots in which we manipulated mangrove cover from 0 to 100 percent. Hurricane Harvey passed over the plots in 2017. Data from erosion stakes indicated up to 26 cm of vertical and 970 cm of horizontal erosion over 70 months in the plot with 0 percent mangrove cover, but relatively little erosion in other plots. The hurricane did not increase erosion, and erosion decreased after the hurricane passed. Data from drone images indicated 196 m2 of erosion in the 0 % mangrove plot, relatively little erosion in other plots, and little ongoing erosion after the hurricane. Transects through the plots indicated that the levee (near the front of the plot) and the bank (the front edge of the plot) retreated up to 9 m as a continuous function of decreasing mangrove cover. Soil strength was greater in areas vegetated with mangroves than in areas vegetated by marsh plants, or nonvegetated areas, and increased as a function of plot-level mangrove cover. Mangroves prevented erosion better than marsh plants did, but this service was non-linear, with low mangrove cover providing most of the benefits.

INTRODUCTION: The diagnosis and treatment of lung cancer is challenged by complex diagnostic pathways and fragmented care that can lead to care disparities for vulnerable patients. METHODS: A multi-institutional, multidisciplinary conference was convened to address the complexity of lung cancer care particularly in patients at high-risk for treatment delay. The resulting care delivery model, called the Lung Cancer Strategist Program (LCSP), was led by a thoracic-trained advanced practice provider (APP) with emphasis on expedited surgery and early oncologic consultation in the assessment of a newly diagnosed suspicious lung nodule. We performed a retrospective review to evaluate care efficiency and oncologic outcomes in the first 100 LCSP patients compared to 100 concurrent patients managed via routine surgical referral. RESULTS: In the 78 LCSP and 41 routine referral patients managed via nodule surveillance, LCSP patients had a shorter time from suspicious finding to work-up (3 vs. 26 days, p < 0.001) and to surveillance decision (12.5 vs. 39 days, p < 0.001). In the 22 LCSP and 59 routine referral patients treated for intrathoracic malignancy, LCSP patients had fewer hospital visits (4 vs 6, p < 0.001), clinicians seen (1.5 vs. 2, p = 0.08), and diagnostic studies (4 vs 5, p = 0.01) with a shorter time to diagnosis (30.5 vs. 48 days, p = 0.02) and treatment (40.5 vs. 68.5 days, p = 0.02). CONCLUSIONS: Patient triage through a thoracic-trained APP in consultation with surgical, medical, and radiation oncology facilitates rapid assessment of benign versus malignant lesions with reduced time to diagnosis and treatment, even among patients at high-risk for treatment delay.

Despite overall global declines, mangroves are expanding into and within many subtropical wetlands, leading to heterogeneous cover of marsh-mangrove coastal vegetation communities near the poleward edge of mangroves' ranges. Coastal wetlands are globally important carbon sinks, yet the effects of shifts in mangrove cover on organic-carbon (OC) storage remains uncertain. We experimentally maintained black mangrove (Avicennia germinans) or marsh vegetation in patches (n = 1,120, 3 × 3 m) along a gradient in mangrove cover (0-100%) within coastal wetland plots (n = 10, 24 × 42 m) and measured changes in OC stocks and fluxes. Within patches, above and belowground biomass (OC) was 1,630% and 61% greater for mangroves than for recolonized marshes, and soil OC was 30% greater beneath mangrove than marsh vegetation. At the plot scale, above and belowground biomass increased linearly with mangrove cover but soil OC was highly variable and unrelated to mangrove cover. Root ingrowth was not different in mangrove or marsh patches, nor did it change with mangrove cover. After 11 months, surface OC accretion was negatively related to plot-scale mangrove cover following a high-wrack deposition period. However, after 22 months, accretion was 54% higher in mangrove patches, and there was no relationship to plot-scale mangrove cover. Marsh (Batis maritima) leaf and root litter had 1,000% and 35% faster breakdown rates (k) than mangrove (A. germinans) leaf and root litter. Soil temperatures beneath mangroves were 1.4°C lower, decreasing aboveground k of fast- (cellulose) and slow-decomposing (wood) standard substrates. Wood k in shallow soil (0-15 cm) was higher in mangrove than marsh patches, but vegetation identity did not impact k in deeper soil (15-30 cm). We found that mangrove cover enhanced OC storage by increasing biomass, creating more recalcitrant organic matter and reducing k on the soil surface by altering microclimate, despite increasing wood k belowground and decreasing allochthonous OC subsidies. Our results illustrate the importance of mangroves in maintaining coastal OC storage, but also indicate that the impacts of vegetation change on OC storage may vary based on ecosystem conditions, organic-matter sources, and the relative spatiotemporal scales of mangrove vegetation change.

Sigren, J.M.; Figlus, J.; Highfield, W.; Feagin, R.A., and Armitage, A.R., 2018. The effects of coastal dune volume and vegetation on storm-induced property damage: Analysis from Hurricane Ike. In response to numerous recent high-profile cases of tropical storm and hurricane damage to coastal communities, there has been increasing attention on the storm protection services provided by coastal ecosystems. However, substantial knowledge gaps exist regarding the quantitative economic benefits of such services, particularly for coastal vegetated dune ecosystems. A novel geographic information system (GIS)-based technique for delineating, quantifying, and relating coastal dune volume, vegetation area, and geographic and built-environment covariates to sustained property damage was used for the upper Texas coast following Hurricane Ike in 2008. The multivariate regression analysis contained more than 1000 homes spanning both sides of the storm's path. Dune volume and vegetation were both significantly ...

Global changes are causing broad-scale shifts in vegetation communities worldwide, including coastal habitats where the borders between mangroves and salt marsh are in flux. Coastal habitats provide numerous ecosystem services of high economic value, but the consequences of variation in mangrove cover are poorly known. We experimentally manipulated mangrove cover in large plots to test a set of linked hypotheses regarding the effects of changes in mangrove cover. We found that changes in mangrove cover had strong effects on microclimate, plant community, sediment accretion, soil organic content, and bird abundance within 2 yr. At higher mangrove cover, wind speed declined and light interception by vegetation increased. Air and soil temperatures had hump-shaped relationships with mangrove cover. The cover of salt marsh plants decreased at higher mangrove cover. Wrack cover, the distance that wrack was distributed from the water's edge, and sediment accretion decreased at higher mangrove cover. Soil organic content increased with mangrove cover. Wading bird abundance decreased at higher mangrove cover. Many of these relationships were non-linear, with the greatest effects when mangrove cover varied from zero to intermediate values, and lesser effects when mangrove cover varied from intermediate to high values. Temporal and spatial variation in measured variables often peaked at intermediate mangrove cover, with ecological consequences that are largely unexplored. Because different processes varied in different ways with mangrove cover, the "optimum" cover of mangroves from a societal point of view will depend on which ecosystem services are most desired.

Several subspecies are defined within Codium fragile, including the invasive C. fragile ssp. fragile, first reported in New Zealand in 1973. An endemic subspecies, Codium fragile ssp. novae-zelandiae, is also found throughout New Zealand. The two subspecies exhibit morphological and molecular variation, although these have never been evaluated together. We compared variation between subspecies at locations in Auckland, identifying subspecies using rps3-rpl16 DNA sequence data, and assessing gross morphological differences, anatomical utricle characters and morphometrics. The taxonomic utility of the morphometric data sets was assessed by linear discriminant analysis. Utricle characters and measurements varied within individual thalli and between different preservation methods. The phenotypes of both subspecies were highly variable and influenced by environment. Accurate subspecies delimitation using morphological data was not possible; the discriminant analyses performed no better than chance for all combinations of the morphological data. Specimens from New Zealand, Canada, Australia and Ireland were sequenced using both the rps3-rpl16 and tufA plastid markers. The tufA elongation factor was shown to be a good candidate for differentiating subspecies of Codium fragile. This marker is twice the length of the rps3- rpl16 spacer, shows greater variation between ssp. fragile and novae-zelandiae, and is less prone to sequencing error. A simple restriction enzyme digest of the tufA amplicon can distinguish ssp. fragile and ssp. novae-zelandiae. Our study expands the known range of the ssp. fragile in New Zealand, including the first record of this subspecies from the west coast of Auckland, and points to a need to re-evaluate morphological and molecular criteria for subspecies currently defined within Codium fragile. This article is protected by copyright. All rights reserved.

Relating the in vitro mitochondrial effects of drug candidates to likely in vivo outcomes remains challenging. Better understanding of this relationship, alongside improved methods to assess mitochondrial dysfunction in vivo, would both guide safer drug candidate selection and better support discovery programmes targeting mitochondria for pharmacological intervention. The aim of this study was to profile the in vivo effects of a compound with suspected complex III electron transport chain (ETC) inhibitory activity (GSK932121A) at doses associated with clinical signs, and relate findings back to in vitro data with the same compound. Control liver mitochondria or HepG2 cells were treated in vitro with GSK932121A to assess mitochondrial effects on both calcium retention capacity (CRC) and oxygen consumption rate (OCR) respectively. The same assessments were then performed on liver mitochondria isolated from Crl:CD(SD) rats, 5 hours following intraperitoneal (IP) administration of GSK932121A. Lactate/pyruvate assessment, hepatic microscopy, blood gas analysis, glutathione profiling and transcriptomics were used to characterise the acute toxicity. In vivo, GSK932121A caused hypothermia, increased levels of hepatocellular oxidative stress and a metabolic shift in energy production, resulting in an increased lactate/pyruvate ratio, liver steatosis and glycogen depletion, together with gene expression changes indicative of a fasted state. As would be expected of an ETC inhibitor, GSK932121A reduced the CRC of liver mitochondria isolated from naive control animals and the OCR of HepG2 cells when treated directly in vitro. In contrast, mitochondria isolated from animals treated with GSK932121A in vivo unexpectedly showed an increase in CRC and basal OCR. Whilst seemingly contradictory, these differences likely reflect an adapted state in vivo resulting from the initial insult in combination with compensatory changes made by the tissue to maintain energy production. Only the initial, unconfounded, response is observable in vitro. These findings improve current understanding of the toxicological and molecular consequences of ETC inhibition. Furthermore, this work highlights key differences in the way that mitochondrial perturbation is manifest in vivo versus in vitro in terms of functional endpoints and helps guide endpoint selection for future studies with potential mitochondrial toxicants or drugs designed to modulate mitochondrial function for therapeutic benefit.

The carbon sequestration potential in coastal soils is linked to aboveground and belowground plant productivity and biomass, which in turn, is directly and indirectly influenced by nutrient input. We evaluated the influence of long-term and near-term nutrient input on aboveground and belowground carbon accumulation in seagrass beds, using a nutrient enrichment (nitrogen and phosphorus) experiment embedded within a naturally occurring, long-term gradient of phosphorus availability within Florida Bay (USA). We measured organic carbon stocks in soils and above- and belowground seagrass biomass after 17 months of experimental nutrient addition. At the nutrient-limited sites, phosphorus addition increased the carbon stock in aboveground seagrass biomass by more than 300 %; belowground seagrass carbon stock increased by 50–100 %. Soil carbon content slightly decreased ( ∼ 10 %) in response to phosphorus addition. There was a strong but non-linear relationship between soil carbon and Thalassia testudinum leaf nitrogen : phosphorus (N : P) or belowground seagrass carbon stock. When seagrass leaf N : P exceeded an approximate threshold of 75 : 1, or when belowground seagrass carbon stock was less than 100 g m−2, there was less than 3 % organic carbon in the sediment. Despite the marked difference in soil carbon between phosphorus-limited and phosphorus-replete areas of Florida Bay, all areas of the bay had relatively high soil carbon stocks near or above the global median of 1.8 % organic carbon. The relatively high carbon content in the soils indicates that seagrass beds have extremely high carbon storage potential, even in nutrient-limited areas with low biomass or productivity.

Coastal wetlands, such as marshes and mangroves, provide many valuable ecosystem services and are vulnerable to climate change and anthropogenic impacts. Marshes are dominant in temperate regions and mangroves within the tropics; both plant types co-occur in subtropical ecotones. Dynamics within marsh-mangrove ecotones may be linked in part to local environmental drivers like nutrient enrichment. Previous studies within monospecific marsh and mangrove stands have reported increases in productivity in response to fertilization; however, the allocation of excess nutrient resources within co-occurring stands of mature plants is not well understood. To investigate nutrient dynamics within the marsh-mangrove ecotone, we fertilized naturally co-occurring Spartina alterniflora and Avicennia germinans stands (the dominant marsh and mangrove species, respectively) within the Gulf of Mexico. After four growing seasons of continuous enrichment, above- and belowground biomass were 2.5 and 1.5 times greater, respectfully, in enriched plots for A. germinans; S. alterniflora biomass did not differ between enrichment treatments. Mangrove leaves indicated a large nutrient response with altered leaf stoichiometry, larger surface area, and greater SPAD (proxy for chlorophyll a) in enriched plots. The fertilization effects may suggest A. germinans has a greater ability to acquire and allocate excess nutrients into productivity and biomass, relative to S. alterniflora, and may therefore be the superior competitor for nutrient resources. In monospecific stands, both marsh and mangroves species have a high potential for nutrient uptake, but when they are co-occurring in the marsh-mangrove ecotone, nutrient retention may be more linked to mangrove ability to partition nutrient resources into various above- and belowground components. Global climate changes are driving mangrove coverage poleward into temperate salt marshes, expanding the areal extent of marsh-mangrove ecotones. At a local scale, these findings reveal that this mangrove expansion may be accelerated by anthropogenic nutrient input.

Black mangroves (Avicennia germinans) are becoming more common along the edges of their range, potentially displacing salt marsh vegetation in transition zones such as the Texas coast in the Gulf of Mexico (USA). Consequences of this shift on trophic interactions within wetland ecosystems are largely unknown. We investigated how increasing mangrove cover might alter predator-prey interactions involving an important consumer in coastal wetlands, blue crabs (Callinectes sapidus), and one of their key prey items, penaeid shrimp (Family Penaeidae). We conducted a series of mesocosm experiments to assess predation rates and prey refuge values in artificial vegetation (AV) matrices simulating flexible marsh grasses (e.g., Spartina patens, Distichlis spicata) and rigid mangrove pneumatophores (aerial root structures). In predation experiments within each of these AV matrices, blue crabs captured 50% fewer penaeid shrimp in the rigid mangrove treatment compared to the flexible marsh treatment, and time between captures was 83% longer among the simulated pneumatophores. In a prey refuge experiment that allowed both predator and prey to move freely among the AV matrices, penaeid shrimp occupied the rigid pneumatophore matrix 30% more often than the grass matrix when blue crabs were present but had no preference when the predator was absent. This study suggests that where A. germinans and marsh grasses co-occur, the mangroves may provide superior refuge for prey items such as penaeid shrimp. Pneumatophores will likely restrict the mobility of predators such as blue crabs, resulting in lower predation efficiency. These results suggest that as mangrove stands continue to increase in cover within mangrove-marsh ecotones, there are likely to be consequences for upper trophic level dynamics.

Global changes, such as increased temperatures and elevated CO2, are driving shifts in plant species distribution and dominance, like woody plant encroachment into grasslands. Local factors within these ecotones can influence the rate of regime shifts. Woody encroachment is occurring worldwide, though there has been limited research within coastal systems, where mangrove (woody shrub/tree) stands are expanding into salt marsh areas. Because coastal systems are exposed to various degrees of nutrient input, we investigated how nutrient enrichment may locally impact mangrove stand expansion and salt marsh displacement over time. We fertilized naturally co-occurring Avicennia germinans (black mangrove) and Spartina alterniflora (smooth cordgrass) stands in Port Aransas, TX, an area experiencing mangrove encroachment within the Northern Gulf of Mexico mangrove-marsh ecotone. After four growing seasons (2010-2013) of continuous fertilization, Avicennia was more positively influenced by nutrient enrichment than Spartina. Most notably, fertilized plots had a higher density of taller (> 0.5 m) mangroves and mangrove maximum height was 46% taller than in control plots. Fertilization may promote an increase in mangrove stand expansion within the mangrove-marsh ecotone by shifting Avicennia height distribution. Avicennia individuals, which reach certain species-specific height thresholds, have reduced negative neighbor effects and have higher resilience to freezing temperatures, which may increase mangrove competitive advantage over marsh grass. Therefore, we propose that nutrient enrichment, which augments mangrove height, could act locally as a positive feedback to mangrove encroachment, by reducing mangrove growth suppression factors, thereby accelerating the rates of increased mangrove coverage and subsequent marsh displacement. Areas within the mangrove-marsh ecotone with high anthropogenic nutrient input may be at increased risk of a regime shift from grass to woody dominated ecosystems.

Borrichia frutescens (L.) DC., sea marigold, is a woody perennial shrub native to the Gulf and Atlantic coasts of North America and has potential as a landscape shrub or groundcover. This study assesses application rates of three commercially available plant growth regulators (PGRs) on B. frutescens during container production. In one experiment, plants were drenched with 0, 0.5, 1, 2, or 4 mg active ingredient (a.i.) pot−1 of uniconazole or 0, 5, 10, 20, or 40 mg a.i. pot−1 of paclobutrazol, and in a second experiment, plants were sprayed with solutions of either 0, 25, 50, 100, or 200 mg a.i. L−1 of uniconazole, 0, 50, 100, 200, or 400 mg a.i. L−1 of paclobutrazol, or 0, 2500, 5000, 10000, or 20000 mg a.i. L−1 of daminozide. Drench-applied paclobutrazol (40 mg a.i. pot−1) reduced shoot mass and root mass (52.9 and 48.5 %, respectively). Both paclobutrazol (40 mg a.i. pot−1) and uniconazole (2 mg a.i. pot−1) reduced leaf number by as much as 56.7 and 23.8 %, respectively. Height was reduced 54.9 % by paclobutrazol at 40 mg a.i. pot−1 and 34.9 % by uniconazole at 2 mg a.i. pot−1. Drench application of paclobutrazol and uniconazole reduced internode extension by 50.1 and 41.4 %, respectively. At the levels tested, daminozide, paclobutrazol, and uniconazole were generally ineffective at controlling growth when applied as a spray. Drench application of paclobutrazol or uniconazole can be used to control height during container production of B. frutescens, whereas spray application rates need to be tested at higher concentrations or multiple applications to achieve desired control.

The primary goal of most habitat restoration projects is to improve ecosystem functions as compensation for habitat loss or degradation, but the optimal engineering approach to achieve that outcome is not always known a priori. Restored coastal wetlands are frequently engineered to create mound and terrace formations at low marsh elevations, but there have been few opportunities to quantitatively compare the ecological characteristics of construction methods that differ in soil source and configuration. Our study took place in a restored (2008) brackish marsh (Texas, USA) that included mounded formations built from on-site soil, off-site dredge material, or a combination of soil sources. We used a two-year (2009–2010) dataset from a restoration monitoring program that included emergent plant, water, soil, aquatic plant, and aquatic faunal characteristics to address two questions: (1) Do construction methods combining different soil sources and dredging techniques confer unique ecological characteristics? (2) Is there an ecological benefit to incorporating heterogeneity in a restored site by employing multiple construction methods? Our analyses revealed that plant root biomass and soil nitrogen and phosphorus concentrations were two times higher in the reference area than in any of the restored areas. Among the restoration construction methods, ecosystem characteristics were similar to each other within two years of restoration. In general, ecosystem characteristics were affected more by temporal variation between years than by construction method. Differences between years were driven by water characteristics; unusually high tides in 2010 doubled salinity and decreased water chlorophyll a concentration and dissolved inorganic nitrogen by half. Although the restored areas did not achieve all reference characteristics during the early development of the site, the differences among engineering approaches were relatively subtle. Therefore, the recommendation for practice is to use the approach that is most cost-effective for a specific site. In our study area, the dredging methods yielded the largest area of emergent marsh per unit effort, but the on-site soil excavations created more aquatic habitat. When ecological integrity is defined as the provision of a wide range of biotic and abiotic conditions at a landscape scale, then the use of different engineering approaches at different sites within a region creates habitat heterogeneity, thus conferring regional-level ecological benefits.