Smithsonian Environmental Research Center Research Articles

Effects of Warming and Elevated CO2 on Stomatal Conductance and Chlorophyll Fluorescence of C3 and C4 Coastal Wetland Species

Coastal wetland communities provide valuable ecosystem services such as erosion prevention, soil accretion, and essential habitat for coastal wildlife, but are some of the most vulnerable to the threats of climate change. This work investigates the combined effects of two climate stressors, elevated temperature (ambient, + 1.7 °C, + 3.4 °C, and 5.1 °C) and elevated CO2 (eCO2), on leaf physiological traits of dominant salt marsh plant species. The research took place at the Salt Marsh Accretion Response to Temperature eXperiment (SMARTX) at the Smithsonian Environmental Research Center, which includes two plant communities: a C3 sedge community and a C4 grass community. Here we present data collected over five years on rates of stomatal conductance (gs), quantum efficiency of PSII photochemistry (Fv/Fm), and rates of electron transport (ETRmax). We found that both warming and eCO2 caused declines in all traits, but the warming effects were greater for the C3 sedge. This species showed a strong negative stomatal response to warming in 2017 and 2018 (28% and 17% reduction, respectively in + 5.1 °C). However, in later years the negative response to warming was dampened to < 7%, indicating that S. americanus was able to partially acclimate to the warming over time. In 2022, we found that sedges growing in the combined + 5.1 °C eCO2 plots exhibited more significant declines in gs, Fv/Fm, and ETRmax than in either treatment individually. These results are important for predicting future trends in growth of wetland species, which serve as a large carbon sink that may help mitigate the effects of climate change.

Leaf traits linked to structure and palatability drive plant-insect interactions within three forested ecosystems.

Plant traits and insect herbivory have been highly studied within the modern record but only to a limited extent within the paleontological. Preservation influences what can be measured within the fossil record, but modern methods are also not compatible with paleobotanical methods. To remedy this knowledge gap, a comparable framework was created here using modern and paleobotanical methods, allowing for future comparisons within the fossil record. Insect feeding damage on selected tree species at Harvard Forest, the Smithsonian Environmental Research Center, and La Selva were characterized using the damage type system prevalent within paleobotanical studies and compared with leaf traits. Linear models and random forest analyses tested the influence of leaf traits on total, specialized, gall, and mine frequency and diversity. Structural traits like leaf dry mass per area and palatability traits, including lignin and phosphorus concentrations, are important variables affecting gall and mine damage. The significance and strength of trait-herbivory relationships varied across forest types, which is likely driven by differences in local insect populations. This work addresses the persistent gap between modern and paleoecological studies focusing on the influence of leaf traits on insect herbivory. This is important as modern climate change alters our understanding of plant-insect interactions, providing a need for contextualizing these relationships within evolutionary time. The fossil record provides information on terrestrial response to past climatic events and, thus, should be implemented when considering how to preserve biodiversity under current and future global change.

Cover Picture and Issue Information

Journal of Animal EcologyVolume 92, Issue 5 p. 945-947 COVER PICTURE AND ISSUE INFORMATIONFree Access Cover Picture and Issue Information First published: 03 May 2023 https://doi.org/10.1111/1365-2656.13721AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Graphical Abstract Cover image: The freshwater snail Physella acuta, a species where antibiotic treatment uncovers a larger extent of shell plasticity. Related article: On the use of antibiotics in plasticity research: Gastropod shells unveil a tale of caution. Photo by Robert Aguilar, Smithsonian Environmental Research Center, used under CC BY 2.0. https://creativecommons.org/licenses/by/2.0/ Volume92, Issue5May 2023Pages 945-947 RelatedInformation

Insect herbivory within modern forests is greater than fossil localities

Fossilized leaves provide the longest running record of hyperdiverse plant-insect herbivore associations. Reconstructions of these relationships over deep time indicate strong links between environmental conditions, herbivore diversity, and feeding damage on leaves. However, herbivory has not been compared between the past and the modern era, which is characterized by intense anthropogenic environmental change. Here, we present estimates for damage frequencies and diversities on fossil leaves from the Late Cretaceous (66.8 Ma) through the Pleistocene (2.06 Ma) and compare these estimates with Recent (post-1955) leaves collected via paleobotanical methods from modern ecosystems: Harvard Forest, United States; the Smithsonian Environmental Research Center, United States; and La Selva, Costa Rica. Total damage frequency, measured as the percentage of leaves with any herbivore damage, within modern ecosystems is greater than any fossil locality within this record. This pattern is driven by increased frequencies across nearly all functional feeding groups within the Recent. Diversities of total, specialized, and mining damage types are elevated within the Recent compared with fossil floras. Our results demonstrate that plants in the modern era are experiencing unprecedented levels of insect damage, despite widespread insect declines. Human influence, such as the rate of global climate warming, influencing insect feeding and timing of life cycle processes along with urbanization and the introduction of invasive plant and insect species may drive elevated herbivory. This research suggests that the strength of human influence on plant-insect interactions is not controlled by climate change alone but rather, the way in which humans interact with terrestrial landscape.

Going remote: Recommendations for normalizing virtual internships

AbstractResearch internships provide students with invaluable experience conducting independent research, contributing to larger research programs, and embedding in a professional scientific setting. These experiences increase student persistence in ecology and other science, technology, engineering, and mathematics (STEM) fields and promote the inclusion of students who lack opportunities at their home institutions and/or are from groups that are underrepresented in STEM. While many ecology internship programs were canceled during the 2020 COVID‐19 pandemic, others successfully adapted to offer virtual internships for the first time. Though different from what many researchers and students envision when they think of internships, virtual ecology internship programs can create more accessible opportunities and be just as valuable as in‐person opportunities when research programs and advisors develop virtual internships with intention and planning. Here, we highlight six ways to structure a virtual intern project, spanning a spectrum from purely computer‐based opportunities (e.g., digital data gathering, data analysis, or synthesis) to fully hands‐on research (e.g., sample processing or home‐based experiments). We illustrate examples of these virtual projects through a case study of the Smithsonian Environmental Research Center's 2020 Virtual Internship Program. Next, we provide 10 recommendations for effectively developing a virtual internship program. Finally, we end with ways that virtual internships can avoid the limitations of in‐person internships, as well as possible solutions to perceived pitfalls of virtual internships. While virtual internships became a necessity in 2020 due to COVID‐19, the development and continuation of virtual internships in future can be a valuable tool to add to the suite of existing internship opportunities, possibly further promoting diversity, equity, and inclusion in ecology and STEM.

Three-dimensional estimation of deciduous forest canopy structure and leaf area using multi-directional, leaf-on and leaf-off airborne lidar data

Airborne laser scanning (ALS) has been widely used to map gap probability and leaf area index (LAI) distribution at plot and landscape scales. As an indirect measurement, most ALS methods to estimate LAI combine waveform or point density information with supporting field measurements such as the leaf angle distribution, gap probability, or direct LAI measures. The development of a more independent estimation approach would facilitate more widespread use of existing ALS data to investigate patterns of forest structure and build realistic 3-D vegetation scenes to simulate remote sensing imagery and energy balance. Here, we develop a data processing workflow (named PVlad) using ALS point cloud apparent reflectance to estimate LAI and voxel-based leaf area density (LAD), aiming to reduce the need for associated field measurements such as the gap probability. The adaptation of the path volume (PV) concept derived from apparent reflectance integrates information from multi-directional ALS pulses, and quantifies the percentage exploration of each voxel for classification and occlusion correction, such that rigorous volumetric sampling approaches can be developed to derive LAI and LAD. The PVlad workflow was applied to discrete-return lidar data (Riegl VQ480i) acquired by NASA Goddard's LiDAR, Hyperspectral and Thermal Imager (G-LiHT) Airborne Imager during leaf-on (summer) and leaf-off (spring) conditions at the Smithsonian Environmental Research Center (SERC). The estimates of LAI and LAD captured structural differences between mature, logged, and intermediate-aged stands over eight deciduous forest plots. The derived LAI values were compared to field litter collection measurements, and the derived LAD vertical distribution was compared to the output of the VoxLAD model using terrestrial laser scan (TLS) field survey data. Using voxel sizes ranging from 0.5 m to 5 m, overall LAI estimation showed linear fitting coefficient bias <0.035 and RMSE<0.5m2/m2 for 1 and 2 m voxel sizes, and vertical LAD distribution showed strong correlation with R≈0.9 and RMSE≈0.028m2/m3 for 0.5 and 1m voxel sizes. For every forest stand, upper-canopy LAD had a low variance for voxel sizes of ≤ 2m. Application of PVlad to the G-LiHT and other similar ALS data archives enables the development of fine-resolution LAI map products, including voxelization of LAD for ecosystem science and radiative transfer simulations of remote sensing imagery or surface energy balance.

Assessing impacts of canopy 3D structure on chlorophyll fluorescence radiance and radiative budget of deciduous forest stands using DART

Although remote sensing (RS) of solar-induced chlorophyll fluorescence (SIF) is increasingly used as a valuable source of information about vegetation photosynthetic activity, the RS SIF observations are significantly influenced by canopy-specific structural features (i.e., canopy architecture including leaf area index and presence of woody components), atmospheric conditions during their acquisition (e.g., proportion of direct and diffuse irradiance) and observational geometric configurations (e.g., sun and viewing directions). Radiative transfer (RT) models have the potential to provide a better understanding of the canopy structural effects on the SIF emission and RS signals. Here, we used the DART model to assess the daily influence, from morning to evening, of forest 3D architecture on SIF nadir radiance, emission, escape factor and nadir yield of eight 100 m × 100 m forest study plots established in a temperate deciduous forest of the Smithsonian Environmental Research Center (Edgewater, MD, USA). The 3D architecture of each plot was derived from airborne LiDAR. DART simulations of these 3D forest plots and their 1D (i.e., vertical profile of sun-adapted and shade-adapted leaves) and 0D (i.e., homogeneous layer of sun-adapted leaves above an homogeneous layer of shade-adapted leaves) abstractions were compared to assess the relative errors (ε1D−3D and ε0D−3D) associated with horizontal and vertical structural heterogeneity, respectively. Forest 3D structure, especially horizontal heterogeneity, had a great influence on forest nadir SIF radiance, resulting in ε1D−3D up to 55% at 8:00 and 18:00 (i.e., for oblique sun directions). The key indicators of this impact, in the descending order of importance, were the SIF escape factor (ε1D−3D up to 40%), the attenuation of incident photosynthetically active radiation (ε1D−3D less than 5%), and the SIF emission yield (ε1D−3D less than 2%). The influence of forest architecture on the nadir SIF escape factor and SIF yield (ε1D−3D up to 40%) varied over time, with differences in forest stand structure, and per spectral domain, being always larger between 640 and 700 nm than between 700 and 850 nm. In addition, woody elements demonstrated a large influence on forest SIF radiance due to their “shading” effect (ε up to 17%) and their “blocking” effect (ε ≈ 10%), both of them higher for far-red than for red SIF. These results underline the importance of 3D forest canopy architecture, especially 2D heterogeneity, and inclusion of woody elements in RT modeling used for interpretation of the RS SIF signal, and subsequently for the estimation of gross primary production and detection of vegetation stress.

Monitoring Non-indigenous Species in Port Habitats: First Application of a Standardized North American Protocol in the Mediterranean Sea

Baseline port monitoring for fouling communities is an essential tool to assess non-indigenous species (NIS) introduction and spread, but a standardized and coordinated method among Mediterranean and European countries has not yet been adopted. In this context, it is important to test monitoring protocols that allow for the collection of standardized and directly comparable data, replicated across time and space. Here, for the first time in the Mediterranean Sea, we tested a standardized protocol developed by the Smithsonian Environmental Research Center (SERC) and used now in several countries. The 3-year monitoring survey (2018–2020) was conducted in the Gulf of La Spezia (Ligurian Sea, Italy), with the deployment of a total of 50 PVC panels per year in five different sites (a commercial harbor, three marinas and a site in the proximity of a shellfish farm). A total of 79 taxa were identified, including 11 NIS, ranging from zero to seven NIS for each panel. In comparison with previous surveys, new NIS arrivals were observed in the Gulf of La Spezia: Botrylloides cf. niger, Branchiomma sp., Branchiomma luctuosum, Paraleucilla magna, and Watersipora arcuata. At the end of the 3-year monitoring, mean richness? and percent cover of NIS were measured, and both measures differed across the monitoring sites, with higher values in two marinas and in the commercial harbor. Among years, richness of NIS was relatively stable at each monitoring site. The structure of the fouling was influenced more by native and cryptogenic species than by NIS. Moreover, among the monitoring sites, the density of artificial structures was not a reliable predictor or proxy for local NIS abundance. This first application of the SERC method in the Mediterranean Sea, demonstrates both pros and cons, including the detection of new NIS reported here. Further direct comparisons with other NIS monitoring tools are recommended, and additional tests to assess its effectiveness in this biogeographical area are encouraged. A broader application of this and other standard methods across temporal and spatial scales in the Mediterranean basin should be implemented, providing critical data needed to assess changes in the structure of fouling communities.

Considering coasts: Adapting terrestrial models to characterize coastal wetland ecosystems

The Energy Exascale Earth System Model (E3SM) simulates fully coupled processes and interactions among water, energy, carbon and nutrient cycles. E3SM connects vegetation and soil dynamics through nutrient uptake, plant production, litterfall and decomposition as a function of abiotic parameters (e.g. temperature and moisture). However, E3SM is designed to characterize terrestrial ecosystems and connects land and open ocean systems using a single streamflow transport term, ignoring the complex dynamics of energy, water, carbon, and nutrients in coastal systems. The goals of our project were to: (1) Parameterize a point version of E3SM to capture coastal wetland habitats and (2) Determine marsh community responses to increased temperature and elevated CO2. We adapted a version of the E3SM land model, previously configured to represent forested bog hydrology to a coastal ecosystem using datasets from field experiments conducted at the Smithsonian Environmental Research Center's Global Change Research Wetland (GCReW). Tidal forcing in a marsh environment was simulated using a two-column system in which the columns are connected by lateral hydrologic flows. One column simulates interactions between vegetation and soil while a second column simulates variation in water level (both tidal and sea level rise). The updated model captures many aspects of the field experiments, showing that plant community responses to environmental change are non-linear, non-additive and different between plant types. Elevated CO2 treatments increased C3 plant biomass more than C4 (33% vs 17%). Temperature exacerbated CO2 responses in C3 plants (0 °C: 26%, 5.1 °C: 56%). We were more successful at characterizing C3 than C4 responses and simulating above rather than belowground biomass production. Next steps will include updates to key physiological parameters such as root:shoot carbon allocation and the addition of mechanistic feedbacks between vegetation and biogeochemical processes.

Microbial and environmental controls on wood decomposition in deciduous forests of different ages

Wood decomposition is regulated by microbial community and soil conditions and plays an important role in global carbon cycling. Among many factors, local conditions, associated with forest age and the leaf litter adjacent to decaying wood may directly and indirectly influence microbial colonization and rate of decay. In this study, wood sticks with and without leaf litter were buried in young (50–70 years), old (120–150 years) and uncut (over 200 years) forests at the Smithsonian Environmental Research Center (SERC), Maryland, USA to test hypotheses about woody and foliar litter interaction during decomposition and whether decay rates are associated with differences in microbial community and soil properties. At the early stages of decomposition, wood mass loss in the young forests was significantly higher than that in other two forests but was not different between old and uncut forests. Adjacent foliar litter increased functional diversity of wood colonizing fungi, and enhanced decay in old and uncut stands. Factors, significantly correlated with decomposition, included fungal community composition, soil moisture, pH and C:N ratio. This study highlights the importance of local factors, such as land use and forest age affecting wood decomposition rates.

Sperm acquisition and storage dynamics facilitate sperm limitation in the selectively harvested blue crab Callinectes sapidus

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 629:87-101 (2019) - DOI: https://doi.org/10.3354/meps13104 Sperm acquisition and storage dynamics facilitate sperm limitation in the selectively harvested blue crab Callinectes sapidus Matthew B. Ogburn*, Kimberly D. Richie, Morgan A. Jones, Anson H. Hines Smithsonian Environmental Research Center, Edgewater, MD 21037, USA *Corresponding author: ogburnm@si.edu ABSTRACT: Selective harvest of male blue crabs Callinectes sapidus can reduce the operational sex ratio and alter male mating history and behaviors, reducing the quantity of sperm females acquire during mating. Females mate shortly after molting to maturity, storing sperm for at least 2 yr, and fertilize multiple broods of eggs. We combined field surveys, a mark-recapture experiment, and modeling in the most extensive study of sperm storage and use after mating in blue crabs evaluating (1) spatiotemporal patterns in sperm quantity acquired during mating, (2) the pattern and rate of decline of sperm during storage, (3) the quantity of sperm used for fertilization, and (4) the potential for sperm limitation. We also explored the spatial extent of spawning in Chesapeake Bay in comparison to the spawning sanctuary. Female crabs acquired up to 3 × 109 sperm, but sperm stores declined by 90-95% in the first 1-2 mo after mating. Sperm quantity differences between first- and second-year spawners indicated use of 4 sperm egg-1 during fertilization. Approximately 15% of spawning females were in their second spawning season, and remaining sperm stores were indicative of sperm limitation resulting in a 5-10% decrease in reproductive output of the spawning stock. The current spawning sanctuary encompassed 98% of ovigerous females and 100% of females with evidence of prior spawning. Although many females do not experience sperm limitation prior to harvest or natural mortality, reductions in the reproductive output of second-year spawners likely limits population resilience to inter-annual variation in spawning stock biomass. KEY WORDS: Sperm limitation · Population dynamics · Reproductive output · Selective harvest · Callinectes sapidus Full text in pdf format PreviousNextCite this article as: Ogburn MB, Richie KD, Jones MA, Hines AH (2019) Sperm acquisition and storage dynamics facilitate sperm limitation in the selectively harvested blue crab Callinectes sapidus. Mar Ecol Prog Ser 629:87-101. https://doi.org/10.3354/meps13104 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 629. Online publication date: October 24, 2019 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2019 Inter-Research.

Controls on soil organic carbon stability and temperature sensitivity with increased aboveground litter input in deciduous forests of different forest ages

A previous 5-year long field litter manipulation study at the Smithsonian Environmental Research Center (SERC) in coastal Maryland demonstrated that forest age controls the chemical trajectory of litter decay and the extent and source of litter incorporation into soil physical fractions among young (60–74 yrs) and old (113–132 yrs) successional stands. To investigate if these ecosystem-level differences influence soil organic carbon (SOC) stability and temperature sensitivity, and to infer differences in stabilization mechanisms, a six-month laboratory incubation (15 °C and 25 °C) of soils from the experimental plots was conducted. The results showed that: 1) C mineralization of wood amended soils was lower than control soils in all forests with young and old forests exhibiting distinct, early vs. late, CO2 efflux profiles over the time course of the incubation; 2) Soils from leaf-amended old forests exhibited a proportional increase in their active SOC pool but with shorter mean residence times (MRT) and a decrease in slow pools with longer MRTs, while SOC of young forests proportionally shifted to more slow cycling SOC pools with MRTs that were unchanged from controls. Structural equation modeling combining previous field and soil property data with laboratory incubation results indicated that temperature sensitivity of the active SOC pool was related to the microbial community and lignin content, while temperature sensitivity of the slow pool was related to chemical protection from silts and clays, environmental factors like pH, and soil C/N ratio. Our results underscore how successional forests of differing age can exhibit dramatically different controls on SOC-litter dynamics, through the protection and accessibility of C, that must be taken into account when predicting forest ecosystem response to future climate change.

Journal entries, maps, and photos help ecologists reconstruct ecosystems of the past

Ilka Feller has a penchant for mangrove hunting. Since the early 2000s, Feller, an ecologist at the Smithsonian Environmental Research Center, has periodically gone road-tripping in search of the northernmost mangrove tree in Florida. The red mangrove, Rhizophora mangle , has draping roots that hold fast in the tide. But all three of Florida’s mangrove species anchor themselves and whole ecosystems—protecting the shoreline from erosion, forming nurseries for fish, and sequestering carbon. Ecologist Ilka Feller used archival records to investigate whether mangroves in Florida, like these in Indian River Lagoon, are expanding into new territories or returning to a historical range. Image credit: Ilka Feller. Globally, mangroves are threatened by coastal development and shrimp farming. “More than half of the world’s mangroves have already been destroyed,” says Feller. Yet in Florida, Feller kept finding new mangroves farther and farther north, “solitary plants that are out there in this forever saltmarsh.” As part of a 2014 study, Feller’s then postdoc, Kyle Cavanaugh, analyzed satellite images taken from 1984 to 2011 and saw that mangroves were indeed advancing northward (1). The spread was associated with a reduced frequency of extreme cold events. Climate change, it seemed, was replacing marshland, an important temperate ecosystem, with mangroves, an important subtropical and tropical one. But had they really revealed a trend pointing in one direction, or was the recent expansion of mangroves part of a continual cycle of mangrove and saltmarsh replacing one another? Feller needed more than just conventional scientific data to find out. So she dug into Florida’s past using tools more typical of historians. She found mangroves mentioned in the texts of famed naturalist John Muir, uncovered data in tourist photos, and parsed the writings of war surgeons and beekeepers. Feller and a growing group of ecologists are piecing together historical records …

Citizen science: Case studies of public involvement in archaeology at the Smithsonian Environmental Research Center

ABSTRACTWhile the citizen science concept has been around for decades, its definition remains fluid in a voluminous literature on the subject. In archaeology, where the concept has had little traction, are we talking about citizens working in science as technicians, or citizens doing science as scientists? Is citizen science in archaeology a marketing rebrand of volunteerism? The Smithsonian Environmental Research Center’s (SERC) archaeology programme offers what may be a unique solution: a consortium of avocational and professional archaeologists in which individuals and small groups, under the guidance of the laboratory’s lead investigator, develop research questions and methods, collect data, analyze, and report results, supported by team members who aid in those tasks that volunteers typically undertake in archaeology; i.e. digging, screening, and washing artefacts. These citizen scientists produce, as well as contribute to, the production of scientific knowledge. Key issues include control, authority, and variable status of participants.

Leaf area density from airborne LiDAR: Comparing sensors and resolutions in a temperate broadleaf forest ecosystem

Forest processes that play an essential role in carbon sequestration, such as light use efficiency, photosynthetic capacity, and trace gas exchange, are closely tied to the three-dimensional structure of forest canopies. However, the vertical distribution of leaf traits is not uniform; leaves at varying vertical positions within the canopy are physiologically unique due to differing light and environmental conditions, which leads to higher carbon storage than if light conditions were constant throughout the canopy. Due to this within-canopy variation, three-dimensional structural traits are critical to improving our estimates of global carbon cycling and storage by Earth system models and to better understanding the effects of disturbances on carbon sequestration in forested ecosystems. In this study, we describe a reproducible and open-source methodology using the R programming language for estimating leaf area density (LAD; the total leaf area per unit of volume) from airborne LiDAR. Using this approach, we compare LAD estimates at the Smithsonian Environmental Research Center in Maryland, USA, from two airborne LiDAR systems, NEON AOP and NASA G-LiHT, which differ in survey and instrument specifications, collections goals, and laser pulse densities. Furthermore, we address the impacts of the spatial scale of analysis as well as differences in canopy penetration and pulse density on LAD and leaf area index (LAI) estimates, while offering potential solutions to enhance the accuracy of these estimates. LAD estimates from airborne LiDAR can be used to describe the three-dimensional structure of forests across entire landscapes. This information can help inform forest management and conservation decisions related to the estimation of aboveground biomass and productivity, the response of forests to large-scale disturbances, the impacts of drought on forest health, the conservation of bird habitat, as well as a host of other important forest processes and responses.

Compliance assessment for the ballast water convention: time for a re-think? A U.K. case study

The damaging introduction of invasive species continues unabated fourteen years after the adoption of the IMO Ballast Water Management Convention (BWMC). The Convention came into force in September, 2017, 13 years after its adoption. Qualifying commercial vessels will need to comply with international discharge regulations and must now contend with complex regulations, uncertain Ballast Water Treatment System performance and potentially inconsistent enforcement internationally. Part of the dilemma rests with the stringent standards which often take days to determine. When certification testing is superseded by rapid Port State Control (PSC) compliance assessment during a port visit, questions arise regarding the logistics of sampling/analysis and the functionality of the BWTS. Reflecting doubts about the performance of installed BWTS IMO have proposed an interim Experience Building Phase (EBP) wherein BWTS non-compliance would not be penalised if operated in good faith. This paper presents a rationale for a robust global programme to test the efficacy of BWTS through Port State Control, using the U.K. as a ‘Case Study’. Rapid prognostic testing during port visits would be employed using technologies certified by regulatory agencies. Such indicative testing would not necessarily address every single aspect of international standards, but would represent robust compliance assessment, that would provide feedback data vital to the improvement of BWTS. Abbreviations: AIS: Aquatic Invasive Species; BWMC: Ballast Water Management Convention; BWTS: Ballast Water Treatment System; CFC: Chlorofluorocarbons; EBP: (IMO) Experience Building Phase; FDOM: Fluorescent Dissolved Organic Matter; HC: Hydrocarbons; HCF: Hydrofluorocarbons; HCFC: Hydrochlorofluorocarbons; IMO: International Maritime Organization; IOPP: International Oil Pollution Prevention; MARPOL: Marine Pollution (Convention); MEPC: IMO Marine Environmental Protection Committee; NOx: Nitrogen oxides; SERC: Smithsonian Environmental Research Center, Edgewater, Maryland, U.S.A.

Shell middens and human technologies as a historical baseline for the Chesapeake Bay, USA

The Chesapeake Bay has an archaeological record that dates from the Paleoindian period to the early 20th century. In this paper, the research and analysis of artifact technologies recovered from six radiocarbon (14C) dated shell middens located at the Smithsonian Environmental Research Center in Maryland is provided. This paper demonstrates the ways in which the use of artifact analysis and 14C dating can provide information on human use of coastal resources, settlement-subsistence patterns, and serve as a tool to document sites threatened by coastal processes. Furthermore, this work demonstrates the ways in which the analysis of technologies from shell midden sites can be used to help guide contemporary oyster and other fisheries and natural resources management, restoration, conservation, and sustainability issues in the Chesapeake and other coastal areas.

Plant biomass and nutrients (C, N and P) in natural, restored and prior converted depressional wetlands in the Mid-Atlantic Coastal Plain, U.S.

Monitoring is an essential component of restoration and measurements of biomass and nutrient concentrations are often used as indicators of ecosystem function. We studied restored depressional wetlands in the U.S. Mid-Atlantic Region. The first study, part of the U.S. Department of Agriculture Conservation Effects Assessment Project (CEAP-Wetlands), compared hydrologically restored wetlands (aged 5–10 years) with natural wetlands and prior converted croplands. We measured aboveground biomass and plant nutrient concentrations at Coastal Plain sites, from Delaware to North Carolina. At the CEAP sites, herbaceous biomass was highest in Restored wetlands, while existing tree biomass was highest in Natural sites. Nutrient concentrations were significantly higher in Prior Converted and Restored sites, relative to Natural sites. In the second study, we compared biomass and nutrient data at a separate set of restored sites, originally sampled by the Smithsonian Environmental Research Center (SERC) in 1994 and resampled in 2011, 15 years later. The primary temporal change was increased tree biomass near the upland-wetland boundary. Both studies indicate that these restored wetlands are in early stages of plant succession, but should develop similarly to natural sites if succession is allowed to progress for decades. This time could be reduced by planting late-successional species characteristic of undisturbed local natural sites. Nutrient data, especially for the SERC wetlands, indicated that these restored wetlands resemble natural sites more in terms of plant nutrient concentrations and that the sites, similar to natural wetlands, will become less nitrogen limited as the impacts of previous agricultural activities decline.

Historical land use and stand age effects on forest soil properties in the Mid-Atlantic US

The conversion of agriculture lands to forest has been occurring in parts of North America for decades. The legacy of management activity during this transition is reflected in soil physical and chemical properties years after abandonment. This study was conducted at the Smithsonian Environmental Research Center, Maryland, USA, to determine land-use history and forest age effects on soil nutrients, carbon, pH, and bulk density. Soils in young and old successional forests and forests with no evidence of historical disturbance were sampled. The young forest stands were abandoned from agriculture 50–70years ago and the old forest stands had been abandoned from agriculture or grazing 120–150years ago. The oldest forest stands had no recorded history of disturbance even though it is likely they were at least disturbed by tree removal or grazing of animals in the colonial era. Young forest soils had higher concentrations of Mg, Ca, NO3 and a higher pH than old, which may be an age effect. The old forest soils that had been abandoned from agriculture and grazing had higher bulk density and lower C content than undisturbed stands indicating a land-use effect. In the stands that were formally agriculture there was evidence of erosion, indicated by a Bt horizon closer to the surface. The most evident difference between stands of different land-use history was the absence of a well-developed O horizon, which we attribute to the presence of earthworms. Land-use legacy set the forest ecosystem in a different trajectory of soil evolution.

Predator-mediated landscape structure: seasonal patterns of spatial expansion and prey control by Chrysaora quinquecirrha and Mnemiopsis leidyi

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 510:183-200 (2014) - DOI: https://doi.org/10.3354/meps10850 Predator-mediated landscape structure: seasonal patterns of spatial expansion and prey control by Chrysaora quinquecirrha and Mnemiopsis leidyi Denise Breitburg*, Rebecca Burrell Smithsonian Environmental Research Center, PO Box 28, Edgewater, Maryland 21037, USA *Corresponding author: breitburgd@si.edu ABSTRACT: The scyphomedusa Chrysaora quinquecirrha and lobate ctenophore Mnemiopsis leidyi are dominant consumers in the planktivorous food web in Chesapeake Bay, USA, and are important predators throughout much of their ranges. Our studies in the Patuxent River (a subestuary of Chesapeake Bay) and its tributary creeks suggest successive waves of population spread and trophic influence of these 2 gelatinous species in opposing directions across the aquatic landscape. In years when both species were abundant, Mnemiopsis appeared first in the main channel of the Patuxent River and initially was most abundant in the bottom layer of the water column. Mnemiopsis densities then rapidly increased in shallow tributaries and coves, with distributions likely caused by a combination of transport and temporally and spatially varying patterns of growth and reproduction. In contrast, densities of Chrysaora ephyrae were initially highest in small coves and tributary creeks, with densities of Chrysaora medusae spreading outward from these small systems to the main river as summer progressed. We found no conclusive evidence for tidally-cued vertical migrations of either species or directional swimming by Chrysaora that would create these differing spatio-temporal patterns. As Chrysaora increased and spread, it likely reduced or eliminated Mnemiopsis by direct predation, and possibly through the effect that partial predation could have on Mnemiopsis reproduction. Because of differences in diets and feeding rates, these shifting temporal and spatial patterns of medusa and ctenophore dominance potentially influence spatial distributions and temporal patterns of survival of ichthyoplankton, oyster larvae, and copepods. KEY WORDS: Gelatinous zooplankton · Estuary · Food web · Spatial distributions · Chesapeake Bay Full text in pdf format Supplementary material PreviousNextCite this article as: Breitburg D, Burrell R (2014) Predator-mediated landscape structure: seasonal patterns of spatial expansion and prey control by Chrysaora quinquecirrha and Mnemiopsis leidyi . Mar Ecol Prog Ser 510:183-200. https://doi.org/10.3354/meps10850 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 510. Online publication date: September 09, 2014 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2014 Inter-Research.