Trajectories of Vegetation Response to Water Management in Taylor Slough, Everglades National Park, Florida

Ecosystem management practices that modify the major drivers and stressors of an ecosystem often lead to changes in plant community composition. This paper examines how closely the trajectory of vegetation change in seasonally-flooded wetlands tracks management-induced alterations in hydrology and soil characteristics. We used trajectory analysis, a multivariate method designed to test hypotheses about rates and directions of community change, to examine vegetation shifts in response to changes in water management practices within the Taylor Slough basin of Everglades National Park. We summarized vegetation data by non-metric multidimensional scaling ordination, and examined the time trajectory of each site along environmental vectors representing hydrology and soil phosphorus gradients. In the Taylor Slough basin, vegetation change trajectories closely followed the hydrologic changes caused by the operation of water pumps and detention ponds adjacent to the canals. We also observed a shift in vegetation composition along a vector of increasing soil phosphorus, which suggests the need for implementing measures to avoid P-enrichment in southern Everglades marl prairies. This study indicates that shifts in vegetation composition in response to changes in hydrologic conditions and associated parameters may be detected through trajectory analysis, thereby providing feedback for adaptive management of wetland ecosystems.

The Influence of Hydrologic Restoration on Groundwater-Surface Water Interactions in a Karst Wetland, the Everglades (FL, USA)

Efforts to rehydrate and restore surface water flow in karst wetlands can have unintended consequences, as these highly conductive and heterogeneous aquifers create a close connection between groundwater and surface water. Recently, hydrologic restoration efforts in the karstic Taylor Slough portion of the Everglades has changed from point source delivery of canal water (direct restoration), to the use of a series of surface water recharge retention basins (diffuse restoration). To determine the influence of restoration on groundwater-surface water interactions in the Taylor Slough headwaters, a water budget was constructed for 1997–2011 using 70 hydro-meteorological stations. With diffuse restoration, groundwater seepage from the Everglades toward the urban boundary increased, while the downstream delivery of surface water to the main portion of the slough declined. The combined influence of diffuse restoration and climate led to increased intra-annual variability in the volume of groundwater and surface water in storage but supported a more seasonally hydrated wetland compared to the earlier direct tactics. The data further indicated that hydrologic engineering in karst wetland landscapes enhances groundwater-surface water interactions, even those designed for restoration purposes.

Seasonal Fish Dispersal in Ephemeral Wetlands of the Florida Everglades

We hypothesized that fishes in short-hydroperiod wetlands display pulses in activity tied to seasonal flooding and drying, with relatively low activity during intervening periods. To evaluate this hypothesis, sampling devices that funnel fish into traps (drift fences) were used to investigate fish movement across the Everglades, U.S.A. Samples were collected at six sites in the Rocky Glades, a seasonally flooded karstic habitat located on the southeastern edge of the Everglades. Four species that display distinct recovery patterns following drought in long-hydroperiod wetlands were studied: eastern mosquitofish (Gambusia holbrooki) and flagfish (Jordanella floridae) (rapid recovery); and bluefin killifish (Lucania goodei) and least killifish (Heterandria formosa) (slow recovery). Consistent with our hypothesized conceptual model, fishes increased movement soon after flooding (immigration period) and just before drying (emigration period), but decreased activity in the intervening foraging period. We also found that eastern mosquitofish and flagfish arrived earlier and showed stronger responses to hydrological variation than either least killifish or bluefin killifish. We concluded that these fishes actively colonize and escape ephemeral wetlands in response to flooding and drying, and display species-specific differences related to flooding and drying that reflect differences in dispersal ability. These results have important implications for Everglades fish metacommunity dynamics.

The status and ecology of the American alligator (Alligator mississippiensis) in Par Pond, Savannah River site

Par Pond is a man-made 1120 ha cooling reservoir located on the Savannah River Site near Aiken, South Carolina. From 1972-1978 a detailed study on the status of the alligator in Par Pond was conducted by Tom Murphy (unpub. MS thesis Univ. of GA, 1977). Murphy estimated that approximately 110 alligators inhabited Par Pond with an adult (> 1.8 m) to juvenile (< 1.8 m) ratio of (1.8:1), an overall sex ratio of 3.2:1, and an average of only 2.3 nests/yr. The purpose of this study (1986-1989) was to determine the current population size and structure, determine how the population has changed in the last 15 years and to examine growth and survival of juvenile alligators. Data were collected by monthly night-time eyeshine counts aerial surveys, capturing animals, and locating and following the fate of nests. There was a strong positive correlation between water temperature and the number of alligators observed during eyeshine counts. Both eyeshine counts and aerial surveys were highest in spring and varied seasonally. A total of 184 different non-hatchling and 157 hatchling alligators were captured between May 1986 and November 1988. Population estimates and size distributions based on capture data indicate that over the last 15 years the population has increased from approximately 110 to 200 alligators, and the size distribution has shifted from one dominated by large adults to one that has a higher proportion of juveniles. The current sex ratio (2.6:1) is not significantly different from that reported by Murphy (1977, 3.2:1). However, the average number of nests/yr has increased from 2.3 to 4.0. Data on juvenile growth and survival show that the growth rate of hatchlings (32.9 cm/yr total length) is greater than that of animals age 1-3 (21.6 cm/yr total length) and survival of all ages is variable between years and between clutches. Results from this study indicate that from 1972-988 the population has increased ac an average exponential rate of 6 % per year. If conditions in Par Pond do not change, the population size should continue to increase.

An Autoregressive Conditional Filtering Process to remove Intraday Seasonal Volatility and its Application to Testing the Noisy Rational Expectations Model

We develop a new autoregressive conditional process to capture both the changes and the persistency of the intraday seasonal (U-shape) pattern of volatility in essay 1. Unlike other procedures, this approach allows for the intraday volatility pattern to change over time without the filtering process injecting a spurious pattern of noise into the filtered series. We show that prior deterministic filtering procedures are special cases of the autoregressive conditional filtering process presented here. Lagrange multiplier tests prove that the stochastic seasonal variance component is statistically significant. Specification tests using the correlogram and cross-spectral analyses prove the reliability of the autoregressive conditional filtering process. In essay 2 we develop a new methodology to decompose return variance in order to examine the informativeness embedded in the return series. The variance is decomposed into the information arrival component and the noise factor component. This decomposition methodology differs from previous studies in that both the informational variance and the noise variance are time-varying. Furthermore, the covariance of the informational component and the noisy component is no longer restricted to be zero. The resultant measure of price informativeness is defined as the informational variance divided by the total variance of the returns. The noisy rational expectations model predicts that uninformed traders react to price changes more than informed traders, since uninformed traders cannot distinguish between price changes caused by information arrivals and price changes caused by noise. This hypothesis is tested in essay 3 using intraday data with the intraday seasonal volatility component removed, as based on the procedure in the first essay. The resultant seasonally adjusted variance series is decomposed into components caused by unexpected information arrivals and by noise in order to examine informativeness.

Land Use and Climate Change Impacts on the Hydrology of the Upper Mara River Basin, Kenya: Results of a Modeling Study to Support Better Resource Management

Some of the most valued natural and cultural landscapes on Earth lie in river basins that are poorly gauged and have incomplete historical climate and runoff records. The Mara River Basin of East Africa is such a basin. It hosts the internationally renowned Mara-Serengeti landscape as well as a rich mixture of indigenous cultures. The Mara River is the sole source of surface water to the landscape during the dry season and periods of drought. During recent years, the flow of the Mara River has become increasingly erratic, especially in the upper reaches, and resource managers are hampered by a lack of understanding of the relative influence of different sources of flow alteration. Uncertainties about the impacts of future climate change compound the challenges. We applied the Soil Water Assessment Tool (SWAT) to investigate the response of the headwater hydrology of the Mara River to scenarios of continued land use change and projected climate change. Under the data-scarce conditions of the basin, model performance was improved using satellite-based estimated rainfall data, which may also improve the usefulness of runoff models in other parts of East Africa. The results of the analysis indicate that any further conversion of forests to agriculture and grassland in the basin headwaters is likely to reduce dry season flows and increase peak flows, leading to greater water scarcity at critical times of the year and exacerbating erosion on hillslopes. Most climate change projections for the region call for modest and seasonally variable increases in precipitation (5–10 %) accompanied by increases in temperature (2.5–3.5 °C). Simulated runoff responses to climate change scenarios were non-linear and suggest the basin is highly vulnerable under low (−3 %) and high (+25 %) extremes of projected precipitation changes, but under median projections (+7 %) there is little impact on annual water yields or mean discharge. Modest increases in precipitation are partitioned largely to increased evapotranspiration. Overall, model results support the existing efforts of Mara water resource managers to protect headwater forests and indicate that additional emphasis should be placed on improving land management practices that enhance infiltration and aquifer recharge as part of a wider program of climate change adaptation.

Microfouling investigations on Fucus vesiculosus and Fucus serratus at outer Kiel Fjord over one year (August 2012 - July 2013)

The present microfouling and bioassay data were used to analyse whether microfouling control of F. vesiculosus and F. serratus against prokaryotes and pennate diatoms fluctuates with season and correlates with in situ microfouling pressure. The two perennial brown macroalgae Fucus vesiculosus and Fucus serratus were sampled monthly from mixed stands at a depth of 0.5 m under mid water level at Bülk, outer Kiel Fjord, Germany (54°27'21 N / 10°11'57 E) within a one-year filed study (August 2012 - July 2013). Microfouler recruitment on glass (reference surface, n = 9 per month) and on both Fucus species (n = 9 per month and Fucus species) was determined monthly. Microfouling control strength of Fucus surface metabolites was tested by an in situ bioassay approach (n = 6 per month and species). For details see related publication Rickert et al. 2016, DOI: 10.1007/s00227-016-2970-3.

Modeled monthly local topographic lapse rates, Pacific Northwest, USA

An emerging approach to downscaling the projections from General Circulation Models (GCMs) to scales relevant for basin hydrology is to use output of GCMs to force higher-resolution Regional Climate Models (RCMs). With spatial resolution often in the tens of kilometers, however, even RCM output will likely fail to resolve local topography that may be climatically significant in high-relief basins. Here we develop and apply an approach for downscaling RCM output using local topographic lapse rates (empirically-estimated spatially and seasonally variable changes in climate variables with elevation). We calculate monthly local topographic lapse rates from the 800-m Parameter-elevation Regressions on Independent Slopes Model (PRISM) dataset, which is based on regressions of observed climate against topographic variables. We then use these lapse rates to elevationally correct two sources of regional climate-model output: (1) the North American Regional Reanalysis (NARR), a retrospective dataset produced from a regional forecasting model constrained by observations, and (2) a range of baseline climate scenarios from the North American Regional Climate Change Assessment Program (NARCCAP), which is produced by a series of RCMs driven by GCMs. By running a calibrated and validated hydrologic model, the Soil and Water Assessment Tool (SWAT), using observed station data and elevationally-adjusted NARR and NARCCAP output, we are able to estimate the sensitivity of hydrologic modeling to the source of the input climate data. Topographic correction of regional climate-model data is a promising method for modeling the hydrology of mountainous basins for which no weather station datasets are available or for simulating hydrology under past or future climates.

Data compilation on the biological response to ocean acidification: environmental and experimental context of data sets and related literature

The exponential growth of studies on the biological response to ocean acidification over the last few decades has generated a large amount of data. To facilitate data comparison, a data compilation hosted at the data publisher PANGAEA was initiated in 2008 and is updated on a regular basis (doi:10.1594/PANGAEA.149999). By January 2015, a total of 581 data sets (over 4 000 000 data points) from 539 papers had been archived. Here we present the developments of this data compilation five years since its first description by Nisumaa et al. (2010). Most of study sites from which data archived are still in the Northern Hemisphere and the number of archived data from studies from the Southern Hemisphere and polar oceans are still relatively low. Data from 60 studies that investigated the response of a mix of organisms or natural communities were all added after 2010, indicating a welcomed shift from the study of individual organisms to communities and ecosystems. The initial imbalance of considerably more data archived on calcification and primary production than on other processes has improved. There is also a clear tendency towards more data archived from multifactorial studies after 2010. For easier and more effective access to ocean acidification data, the ocean acidification community is strongly encouraged to contribute to the data archiving effort, and help develop standard vocabularies describing the variables and define best practices for archiving ocean acidification data.

Capparaceae: flora do Rio Grande do Norte e biogeografia no semiárido brasileiro

Capparaceae comprises 25 genera and 480 species, of which 110 are included in 18 genera in Neotropics. Its distribution is pantropical with high frequency in seasonally dry environments. Its representatives are woody, shrubs and rarely wines, with simple leave or compound 3-foliolate, shorts and deciduous floral bracts, tetramerous and nocturnal flowers with exserts and numerous stamens, ovary supero on a gynophore and fleshy fruits, dehiscents or indehiscentes. For Brazil, 12 genera and 28 species are recorded and 12 of that are endemic to the country, occurring preferentially in vegetation of savanna estépica s.str., seasonal semideciduos forest and restinga. This work shows two chapters. In the first chapter, the distributions patterns of the species occurring in the brazilian semi-arid region and their distribution intra Caatinga are discussed. The distribution patterns were determined from a review of the distribution of species in herbaria collections and supplemented with data obtained from specific bibliography about the family. A map containing 1 × 1 grid cells was used to evaluate the richness, collection efforts and floristic similarity of the species intra Caatinga. Six genera and eight species were registered in Caatinga. Four species are endemic to Brazil, with only one endemic to Caatinga, and the other four are widespread in Neotropics. Four distribution patterns were observed: restricted to the NE, broad and continuous in Brazil, disjunct and neotropical. All the species were recorded in Bahia, state with the highest species richness per grid cell and also remarkable sampling efforts species of the family. The state of Piauí presents priority areas for further collection of Capparaceae, due to low family representation in the state. The floristic similarity analysis intra Caatinga was low, 22 %, probably due to a few species of the family in the region and the wide distribution of the same. The second chapter presents the Capparaceae of flora to Rio Grande do Norte (RN), since the state has a little-known flora, with specific studies. Through collections in the state and herbaria review, five genera and six species of Capparaceae were recorded in RN: Capparidastrum (1 spp.); Crateva (1 spp.); Cynophalla (2 spp.); Mesocapparis (1 spp.) and Neocalyptrocalyx (1 spp.). Capparidastrum frondosum and Mesocapparis lineata are new records for the state. An identification key, descriptions and images, comments on the biology of the species and protected areas where they occur are showed.

Effect of the environment on condition and quality of cultured blue mussels (Mytilus edulis) with reference to culture depth and post-harvest practices

The condition and quality of cultured blue mussels (Mytilus edulis) are affected by various environmental characteristics including temperature, salinity, food concentration, composition and year-to-year variability, waves, tides, and currents. Mussels are a keystone species in the ecosystem, affecting the surrounding environment through filtration, biodeposition and nutrient recycling. This study evaluated the effects of culture depth and post-harvest handling on cultured blue mussels in Newfoundland, Canada. Depth was examined over two years; three shallow water (5 m depth) and three deep water sites (15 m depth) were compared for environmental characteristics, mussel physiological stress response, growth, and biochemical composition. The area examined presented complex hydrodynamic characteristics; deep water sites appeared to be located more often near or within the pycnocline than shallow water sites. Deep water sites presented lower temperatures than shallow sites from spring to fall. Physiological stress response varied seasonally, but was unaffected by culture depth. In Year 1 shallow and deep water mussels presented similar growth, while in Year 2 deep water mussels showed better final condition. Lipid and glycogen showed seasonal variation, but no significant differences between shallow and deep water were noted. Fatty acid profiles showed a higher content of omega-3s PUFA in deep water sites at the end of Year 2. Under extreme weather conditions, deep water appeared to provide a more stable environment for mussel growth than shallow water. Harvested mussels were kept under ambient live-holding conditions for one month during the fall, winter, and spring seasons. They were compared to freshly harvested mussels for condition, biochemical profile and palatability. A progressive loss of dry tissue weight and an increase in water content were shown over the holding period during the fall and spring seasons, when compared to field controls. The biochemical analysis suggested seasonal changes; differences in triacylglycerol content were found in the spring season when compared with controls. The palatability data indicated that the panellists were unable to determine a difference between mussels kept in holding and those freshly harvested from the site. This study presents new knowledge for mussel farming, especially in terms of environmental interactions and deep water culture.

Age models and stable isotopes of sediment cores from the northern seas

Oxygen and carbon isotope measurements were carried out on tests of planktic foraminifers N. pachyderma (sin.) from eight sediment cores taken from the eastern Arctic Ocean, the Fram Strait, and the lceland Sea, in order to reconstruct Arctic Ocean and Norwegian-Greenland Sea circulation patterns and ice covers during the last 130,000 years. In addition, the influence of ice, temperature and salinity effects on the isotopic signal was quantified. Isotope measurements on foraminifers from sediment surface samples were used to elucidate the ecology of N. pachyderma (sin.). Changes in the oxygen and carbon isotope composition of N. pachyderma (sin.) from sediment surface samples document the horizontal and vertical changes of water mass boundaries controlled by water temperature and salinity, because N. pachyderma (sin.) shows drastic changes in depth habitats, depending on the water mass properties. It was able to be shown that in the investigated areas a regional and spatial apparent increase of the ice effect occurred. This happened especially during the termination I by direct advection of meltwaters from nearby continents or during the termination and in interglacials by supply of isotopically light water from rivers. A northwardly proceeding overprint of the 'global' ice effect, increasing from the Norwegian-Greenland Sea to the Arctic Ocean, was not able to be demonstrated. By means of a model the influence of temperature and salinity on the global ice volume signal during the last 130,000 years was recorded. In combination with the results of this study, the model was the basis for a reconstruction of the paleoceanographic development of the Arctic Ocean and the Norwegian-Greenland Sea during this time interval. The conception of a relatively thick and permanent sea ice cover in the Nordic Seas during glacial times should be replaced by the model of a seasonally and regionally highly variable ice cover. Only during isotope stage 5e may there have been a local deep water formation in the Fram Strait.

Antarctic sympagic meiofauna in winter

This study of Antarctic sympagic meiofauna in pack ice during late winter compares communities between the perennially ice-covered western Weddell Sea and the seasonally ice-covered southern Indian Ocean. Sympagic meiofauna (proto- and metazoans > 20 µm) and eggs > 20 µm were studied in terms of diversity, abundance and carbon biomass, and with respect to vertical distribution. Metazoan meiofauna had significantly higher abundance and biomass in the western Weddell Sea (medians: 31.1 * 10**3/m**2 and 6.53 mg/m**2, respectively) than in the southern Indian Ocean (medians: 1.0 * 10**3 /m**2 and 0.06 mg/m**2, respectively). Metazoan diversity was also significantly higher in the western Weddell Sea. Furthermore, the two regions differed significantly in terms of meiofauna community composition, as revealed through multivariate analyses. The overall diversity of sympagic meiofauna was high, and integrated abundance and biomass of total meiofauna were also high in both regions (0.6 - 178.6 * 10**3/m**2 and 0.02 - 89.70 mg/m**2, respectively), mostly exceeding values reported earlier from the western Weddell Sea in winter. We attribute the differences in meiofauna communities between the two regions to the older first-year ice and multi-year ice that is present in the western Weddell Sea, but not in the southern Indian Ocean. Our study indicates the significance of perennially ice-covered regions for the establishment of diverse and abundant meiofauna communities. Furthermore, it highlights the potential importance of sympagic meiofauna for the organic matter pool and trophic interactions in sea ice.

Isotopic data of atmospheric methane from EDML and Vostok ice cores over a full glacial cycle

The response of natural CH4 sources to climate changes will be an important factor to consider as concentrations of this potent greenhouse gas continue to increase. Polar ice cores provide the means to assess this sensitivity in the past and have shown a close connection between CH4 levels and northern hemisphere temperature variability over the last glacial cycle. However, the contribution of the various CH4 sources and sinks to these changes is still a matter of debate. Contemporaneous stable CH4 isotope records in ice cores provide additional boundary conditions for assessing changes in the CH4 sources and sinks. Here we present new ice core CH4 isotope data covering the last 160,000 years, showing a clear decoupling between CH4 loading and carbon isotopic variations over most of the record. We suggest that d13CH4 variations were not dominated by a change in the source mix but rather by climate- and CO2-related ecosystem control on the isotopic composition of the methane precursor material, especially in seasonally inundated wetlands in the tropics. In contrast, relatively stable d13CH4 intervals occurred during large CH4 loading changes concurrently with past climate changes implying that most CH4 sources (most notably tropical wetlands) responded simultaneously.

(Table 2) Age determination of sediment cores from the continental shelf of Mac Roberston Land, East Antarctica

Geochemical records are presented for five sediment cores from basins on the continental shelf of Mac. Robertson Land, East Antarctica. The cores contain 2-4 m thick sequences of hemipelagic, siliceous mud and ooze (SMO) deposited under seasonally open marine conditions. The inner and middle shelf SMO sequences are massive dark olive green material, whereas the outer shelf SMO sequences are dark olive material interspersed with light olive green layers ~1-10 cm thick. The biogenic material is dominated by marine diatoms including Fragilariopsis curta, Fragilariopsis cylindrus, and Chaetoceros spp. in the dark-colored SMO and Corethron criophilum in the light-colored layers. Radiocarbon dates suggest that the cores provide continuous accumulation records extending from < 1 kyr before present (B.P.) back as far as 4-15 kyr B.P., with estimated accumulation rates of 0.07-5 mm/yr. The three core records from the middle and outer shelf suggest six episodes of increased accumulation of biogenic material at ~5.5 kyr B.P. (all three cores), 1, 2, and 6.2 kyr B.P. (two of the three cores), and 3.8 and 10.8 kyr B.P. (one core), most of which coincide with Corethron layers. We interpret these features as the result of enhanced diatom production over the outer shelf, possibly related to climatic warm periods. The absence of such features in the inner shelf core records is thought to reflect a relatively constant level of seasonal diatom production in adjacent waters maintained by a coastal polynya.