Physical Sciences and Mathematics Commons^™

Marsh Persistence Under Sea-Level Rise Is Controlled By Multiple, Geologically Variable Stressors, Molly Mitchell, Julie Herman, Donna M. Bilkovic, Carl Hershner

VIMS Articles

Introduction: Marshes contribute to habitat and water quality in estuaries and coastal bays. Their importance to continued ecosystem functioning has led to concerns about their persistence.

Outcomes: Concurrent with sea-level rise, marshes are eroding and appear to be disappearing through ponding in their interior; in addition, in many places, they are being replaced with shoreline stabilization structures. We examined the changes in marsh extent over the past 40 years within a subestuary of Chesapeake Bay, the largest estuary in the United States, to better understand the effects of sea-level rise and human pressure on marsh coverage.

Sea Level Rise May Increase Extinction Risk Of A Saltmarsh Ontogenetic Habitat Specialist, David S. Johnson, Bethany L. Williams

VIMS Articles

Specialist species are more vulnerable to environmental change than generalist species. For species with ontogenetic niche shifts, specialization may occur at a particular life stage making those stages more susceptible to environmental change. In the salt marshes in the northeast U.S., accelerated sea level rise is shifting vegetation patterns from flood-intolerant species such as Spartina patens to the flood-tolerant Spartina alterniflora. We tested the potential impact of this change on the coffee bean snail, Melampus bidentatus, a numerically dominant benthic invertebrate with an ontogenetic niche shift. From a survey of eight marshes throughout the northeast U.S., small snails …

A Test Bed For Coastal And Ocean Modeling, R. A. Luettich Jr., L. D. Wright, C. R. Nichols, R. Baltes, M. A.M. Friedrichs, Et Al

VIMS Articles

No abstract provided.

Multifaceted Biodiversity Hotspots Of Marine Mammals For Conservation Priorities, Camille Albouy, Valentine L. Delattre, Bastien Merigot, Christine N. Meynard, Fabien Leprieur

VIMS Articles

Aim: Identifying the multifaceted biodiversity hotspots for marine mammals and their spatial overlap with human threats at the global scale.

Climate Change Impacts On Southern Ross Sea Phytoplankton Composition, Productivity, And Export, Daniel E. Kaufman, Marjorie A. M. Friedrichs, Walker O. Smith Jr., Eileen E. Hofmann, Michael S. Dinniman, John C. P. Hemmings

VIMS Articles

The Ross Sea, a highly productive region of the Southern Ocean, is expected to experience warming during the next century along with reduced summer sea ice concentrations and shallower mixed layers. This study investigates how these climatic changes may alter phytoplankton assemblage composition, primary productivity, and export. Glider measurements are used to force a one-dimensional biogeochemical model, which includes diatoms and both solitary and colonial forms of Phaeocystis antarctica. Model performance is evaluated with glider observations, and experiments are conducted using projections of physical drivers for mid-21st and late-21st century. These scenarios reveal a 5% increase in primary productivity …

Temporal Progression Of Photosynthetic-Strategy In Phytoplankton In The Ross Sea, Antarctica, T. J. Ryan-Keogh, L. M. Delizo, Walker O. Smith Jr., Et Al

VIMS Articles

The bioavailability of iron influences the distribution, biomass and pioductivity of phytoplankton in the Ross Sea, one of the most productive regions in the Southern Ocean. We mapped the spatial and temporal extent and severity of iron-limitation of the native phytoplankton assemblage using long- (>24 h) and short-term (24 h) iron-addition experiments along with physiological and molecular characterisations during a cruise to the Ross Sea in December February 2012. Phytoplankton increased their photosynthetic efficiency in response to iron addition, suggesting proximal iron limitation throughout most of the Ross Sea during summer. Molecular and physiological data further indicate that as …

Preliminary Estimate Of Contribution Of Arctic Nitrogen Fixation To The Global Nitrogen Budget, Rachel E. Sipler, Donglai Gong, Se Baer, Mp Sanderson, Qn Roberts, M Mulholland, Da Bronk

VIMS Articles

Dinitrogen (N-2) fixation is the source of all biologically available nitrogen on earth, and its presence or absence impacts net primary production and global biogeochemical cycles. Here, we report rates of 3.5-17.2 nmol N L-1 d(-1) in the ice-free coastal Alaskan Arctic to show that N-2 fixation in the Arctic Ocean may be an important source of nitrogen to a seasonally nitrogen-limited system. If widespread in surface waters over ice-free shelves throughout the Arctic, N-2 fixation could contribute up to 3.5 Tg N yr(-1) to the Arctic nitrogen budget. At these rates, N-2 fixation occurring in ice-free summer waters would …

Ocean Acidification Compromises A Planktic Calcifier With Implications For Global Carbon Cycling, Cv Davis, Emily B. Rivest, Et Al

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Anthropogenically-forced changes in ocean chemistry at both the global and regional scale have the potential to negatively impact calcifying plankton, which play a key role in ecosystem functioning and marine carbon cycling. We cultured a globally important calcifying marine plankter (the foraminifer, Globigerina bulloides) under an ecologically relevant range of seawater pH (7.5 to 8.3 total scale). Multiple metrics of calcification and physiological performance varied with pH. At pH > 8.0, increased calcification occurred without a concomitant rise in respiration rates. However, as pH declined from 8.0 to 7.5, calcification and oxygen consumption both decreased, suggesting a reduced ability to precipitate …

Assessing The Impact Of Local And Regional Influences On Nitrogen Loads To Buzzards Bay, Ma, Shanna C. Williamson, Jennie E. Rheuban, Et Al

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Nitrogen and chlorophyll-a concentrations in estuarine systems often correlate positively with increased nitrogen input. To determine the interactions between nitrogen load, physical drivers, and water quality indicators, we estimated nitrogen inputs to 28 estuaries within the Buzzards Bay, Massachusetts (USA) watershed from 1985 to 2013. Estimates were derived by combining parcel specific wastewater disposal, point source wastewater discharge, land use, and atmospheric nitrogen deposition data with a previously verified nitrogen loading model. Linear regression analysis was used to quantify temporal trends in individual data sets and characterize relationships between variables. The land-use data indicated that fractional coverage of impervious surfaces …

Assessing National Biodiversity Trends For Rocky And Coral Reefs Through The Integration Of Citizen Science And Scientific Monitoring Programs, Rochelle Stuart-Smith, Gj Edgar, Et Al, Js Lefcheck

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Reporting progress against targets for international biodiversity agreements is hindered by a shortage of suitable biodiversity data. We describe a cost-effective system involving Reef Life Survey citizen scientists in the systematic collection of quantitative data covering multiple phyla that can underpin numerous marine biodiversity indicators at high spatial and temporal resolution. We then summarize the findings of a continental- and decadal-scale State of the Environment assessment for rocky and coral reefs based on indicators of ecosystem state relating to fishing, ocean warming, and invasive species and describing the distribution of threatened species. Fishing impacts are widespread, whereas substantial warming-related change …