Open Access. Powered by Scholars. Published by Universities.®

Life Sciences Commons

Open Access. Powered by Scholars. Published by Universities.®

Articles 1 - 24 of 24

Full-Text Articles in Life Sciences

An Operational Overview Of The Export Processes In The Ocean From Remote Sensing (Exports) Northeast Pacific Field Deployment, David A. Siegel, Ivona Cetinic, (...), Deborah K. Steinberg, Et Al Jan 2021

An Operational Overview Of The Export Processes In The Ocean From Remote Sensing (Exports) Northeast Pacific Field Deployment, David A. Siegel, Ivona Cetinic, (...), Deborah K. Steinberg, Et Al

VIMS Articles

The goal of the EXport Processes in the Ocean from RemoTe Sensing (EXPORTS) field campaign is to develop a predictive understanding of the export, fate, and carbon cycle impacts of global ocean net primary production. To accomplish this goal, observations of export flux pathways, plankton community composition, food web processes, and optical, physical, and biogeochemical (BGC) properties are needed over a range of ecosystem states. Here we introduce the first EXPORTS field deployment to Ocean Station Papa in the Northeast Pacific Ocean during summer of 2018, providing context for other papers in this special collection. The experiment was conducted with …


Effects Of Seawater Exchange On Water Chemistry Among Coastal Lakes With Intermittent Connections To The Sea, A. Challen Hyman, Dana Bigham Stephens Oct 2020

Effects Of Seawater Exchange On Water Chemistry Among Coastal Lakes With Intermittent Connections To The Sea, A. Challen Hyman, Dana Bigham Stephens

VIMS Articles

Intermittently closed and open lakes and lagoons (ICOLLs) are a dynamic class of coastal waterbodies with the unique feature of intermittently connecting to the sea. Understanding the functioning and potential threats of these globally rare systems is important to their preservation and protection. Coastal dune lakes of northwest Florida are one example of an understudied group of ICOLLs which connect with the Gulf of Mexico for brief periods of time. Using a 17-year, monthly water chemistry dataset, we analyzed long-term patterns in water chemistry among 16 coastal dune lakes. Using salinity as a proxy for frequency of seawater inflows, principal …


Relative Impacts Of Global Changes And Regional Watershed Changes On The Inorganic Carbon Balance Of The Chesapeake Bay, Pierre St-Laurent, Marjorie A.M. Friedrichs, Raymond G. Najjar, Elizabeth Shadwick, Hanquin Tian, Yuanzhi Yao Jul 2020

Relative Impacts Of Global Changes And Regional Watershed Changes On The Inorganic Carbon Balance Of The Chesapeake Bay, Pierre St-Laurent, Marjorie A.M. Friedrichs, Raymond G. Najjar, Elizabeth Shadwick, Hanquin Tian, Yuanzhi Yao

VIMS Articles

The Chesapeake Bay is a large coastal-plain estuary that has experienced considerable anthropogenic changeover the past century. At the regional scale, land-use change has doubled the nutrient input from rivers and led to an increase in riverine carbon and alkalinity. The bay has also experienced global changes, including the rise of atmospheric temperature and CO2. Here we seek to understand the relative impact of these changes on the inorganic carbon balance of the bay between the early 1900s and the early 2000s. We use a linked land–estuarine–ocean modeling system that includes both inorganic and organic carbon and nitrogen cycling. Sensitivity …


Zooplankton Diel Vertical Migration During Antarctic Summer, John A. Conroy, Deborah K. Steinberg, Patrica S. Thibodeau, Oscar Schofield Jun 2020

Zooplankton Diel Vertical Migration During Antarctic Summer, John A. Conroy, Deborah K. Steinberg, Patrica S. Thibodeau, Oscar Schofield

VIMS Articles

Zooplankton diel vertical migration (DVM) during summer in the polar oceans is presumed to be dampened due to near continuous daylight. We analyzed zooplankton diel vertical distribution patterns in a wide range of taxa along the Western Antarctic Peninsula (WAP) to assess if DVM occurs, and if so, what environmental controls modulate DVM in the austral summer. Zooplankton were collected during January and February in paired day-night, depth-stratified tows through the mesopelagic zone along the WAP from 2009-2017, as well as in day and night epipelagic net tows from 1993-2017. The copepod Metridia gerlachei, salp Salpa thompsoni, pteropod …


Providential Tides: The Double Low Water Of Narragansett Bay, D. G. Bowers, J. M. Brubaker May 2020

Providential Tides: The Double Low Water Of Narragansett Bay, D. G. Bowers, J. M. Brubaker

VIMS Articles

We investigate a mechanism for producing double-lows and double-highs in the semi-diurnal tide by selective amplification of higher harmonics in a resonant gulf. A double low water is observed at Providence, RI, near the head of Narragansett Bay on days when there is a flattening of the low water tidal curve at Newport, at the mouth of the bay. The flattening is caused by an unusually large quarter-diurnal component to the tide at Newport. The quarter diurnal component has the right phase (a maximum close to the time of the minimum in the semi-diurnal tide) to produce a prolonged flattening …


The Importance Of Antarctic Krill In Biogeochemical Cycles, El Cavan, A Belcher, Sl Hill, S Kawaguchi, S Mccormack, B Meyer, S Nicol, K Schmidt, Deborah K. Steinberg, Ga Tarling, Pw Boyd Oct 2019

The Importance Of Antarctic Krill In Biogeochemical Cycles, El Cavan, A Belcher, Sl Hill, S Kawaguchi, S Mccormack, B Meyer, S Nicol, K Schmidt, Deborah K. Steinberg, Ga Tarling, Pw Boyd

VIMS Articles

Antarctic krill (Euphausia superba) are swarming, oceanic crustaceans, up to two inches long, and best known as prey for whales and penguins – but they have another important role. With their large size, high biomass and daily vertical migrations they transport and transform essential nutrients, stimulate primary productivity and influence the carbon sink. Antarctic krill are also fished by the Southern Ocean’s largest fishery. Yet how krill fishing impacts nutrient fertilisation and the carbon sink in the Southern Ocean is poorly understood. Our synthesis shows fishery management should consider the influential biogeochemical role of both adult and larval …


Scientific Considerations For Acidification Monitoring In The Us Mid-Atlantic Region, Ka Goldsmith, S Lau, Et Al, Eh Shadwick, Et Al Sep 2019

Scientific Considerations For Acidification Monitoring In The Us Mid-Atlantic Region, Ka Goldsmith, S Lau, Et Al, Eh Shadwick, Et Al

VIMS Articles

Coastal and ocean acidification has the potential to cause significant environmental and societal impacts. Monitoring carbonate chemistry parameters over spatial and temporal scales is challenging, especially with limited resources. A lack of monitoring data can lead to a limited understanding of real-world conditions. Without such data, robust experimental and model design is challenging, and the identification and understanding of episodic acidification events is nearly impossible. We present considerations for resource managers, academia, and industry professionals who are currently developing acidification monitoring programs in the Mid-Atlantic region. We highlight the following considerations for deliberation: 1) leverage existing infrastructure to include multiple …


It’S About Time: A Synthesis Of Changing Phenology In The Gulf Of Maine Ecosystem, Md Staudinger, Ke Mills, Et Al, David S. Johnson, Et Al Aug 2019

It’S About Time: A Synthesis Of Changing Phenology In The Gulf Of Maine Ecosystem, Md Staudinger, Ke Mills, Et Al, David S. Johnson, Et Al

VIMS Articles

The timing of recurring biological and seasonal environmental events is changing on a global scale relative to temperature and other climate drivers. This study considers the Gulf of Maine ecosystem, a region of high social and ecological importance in the Northwest Atlantic Ocean and synthesizes current knowledge of (a) key seasonal processes, patterns, and events; (b) direct evidence for shifts in timing; (c) implications of phenological responses for linked ecological-human systems; and (d) potential phenology-focused adaptation strategies and actions. Twenty studies demonstrated shifts in timing of regional marine organisms and seasonal environmental events. The most common response was earlier timing, …


Treading Water: Tools To Help Us Coastal Communities Plan For Sea Level Rise Impacts, E A. Smith, W Sweet, Molly Mitchell, R Domingues, C P. Weaver, M Baringer, G Goni, J Haines, Jon Derek Loftis, John D. Boon, David L. Malmquist Jun 2019

Treading Water: Tools To Help Us Coastal Communities Plan For Sea Level Rise Impacts, E A. Smith, W Sweet, Molly Mitchell, R Domingues, C P. Weaver, M Baringer, G Goni, J Haines, Jon Derek Loftis, John D. Boon, David L. Malmquist

VIMS Articles

As communities grapple with rising seas and more frequent flooding events, they need improved projections of future rising and flooding over multiple time horizons, to assist in a multitude of planning efforts. There are currently a few different tools available that communities can use to plan, including the Sea Level Report Card and products generated by a United States. Federal interagency task force on sea level rise. These tools are a start, but it is recognized that they are not necessarily enough at present to provide communities with the type of information needed to support decisions that range from seasonal …


Alkalinity In Tidal Tributaries Of The Chesapeake Bay, R. G. Najjar, M. Herrmann, S. M. Cintrón Del Valle, Jaclyn R. Friedman, Marjorie A.M. Friedrichs, Et Al Jan 2019

Alkalinity In Tidal Tributaries Of The Chesapeake Bay, R. G. Najjar, M. Herrmann, S. M. Cintrón Del Valle, Jaclyn R. Friedman, Marjorie A.M. Friedrichs, Et Al

VIMS Articles

Despite the important role of alkalinity in estuarine carbon cycling, the seasonal and decadal variability of alkalinity, particularly within multiple tidal tributaries of the same estuary, is poorly understood. Here we analyze more than 25,000 alkalinity measurements, mostly from the 1980s and 1990s,in the major tidal tributaries of the Chesapeake Bay, a large, coastal‐plain estuary of eastern North America.The long‐term means of alkalinity in tidal‐fresh waters vary by a factor of 6 among seven tidal tributaries,reflecting the alkalinity of nontidal rivers draining to these estuaries. At 25 stations, mostly in the Potomac River Estuary, wefind significant long‐term increasing trends that …


Ocean Change Within Shoreline Communities: From Biomechanics To Behaviour And Beyond, Brian Gaylord, Kristina M. Barclay, Brittany M. Jellison, Laura L. Jurgens, Aaron T. Ninokawa, Emily B. Rivest, Lindsey R. Leighton Jan 2019

Ocean Change Within Shoreline Communities: From Biomechanics To Behaviour And Beyond, Brian Gaylord, Kristina M. Barclay, Brittany M. Jellison, Laura L. Jurgens, Aaron T. Ninokawa, Emily B. Rivest, Lindsey R. Leighton

VIMS Articles

Humans are changing the physical properties of Earth. In marine systems, elevated carbon dioxide concentrations are driving notable shifts in temperature and seawater chemistry. Here, we consider consequences of such perturbations for organism biomechanics and linkages amongst species within communities.In particular,we examine case examples of altered morphologies and material properties, disrupted consumer–prey behaviours, and the potential for modulated positive (i.e. facilitative) interactions amongst taxa, as incurred through increasing ocean acidity and rising temperatures. We focus on intertidal rocky shores of temperate seas as model systems, acknowledging the longstanding role of these communities in deciphering ecological principles. Our survey illustrates the …


Symbiotic Unicellular Cyanobacteria Fix Nitrogen In The Arctic Ocean, K. Harding, K. A. Turk-Kubo, Rachel E. Sipler, M. M. Mills, D. A. Bronk Dec 2018

Symbiotic Unicellular Cyanobacteria Fix Nitrogen In The Arctic Ocean, K. Harding, K. A. Turk-Kubo, Rachel E. Sipler, M. M. Mills, D. A. Bronk

VIMS Articles

Biological dinitrogen (N2) fixation is an important source of nitrogen (N) in low-latitude open oceans. The unusual N2-fixing unicellular cyanobacteria (UCYN-A)/haptophyte symbiosis has been found in an increasing number of unexpected environments, including northern waters of the Danish Straight and Bering and Chukchi Seas. We used nanoscale secondary ion mass spectrometry (nanoSIMS) to measure 15N2 uptake into UCYN-A/haptophyte symbiosis and found that UCYN-A strains identical to low-latitude strains are fixing N2 in the Bering and Chukchi Seas, at rates comparable to subtropical waters. These results show definitively that cyanobacterial N2 fixation is not constrained to subtropical waters, challenging paradigms and …


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 Jan 2017

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 …


Interactive Effects Of Elevated Temperature And Co2 On Nitrate, Urea, And Dissolved Inorganic Carbon Uptake By A Coastal California, Usa, Microbial Community, Jl Spackeen, Rachel E. Sipler, K Xu, Et Al, Da Bronk Jan 2017

Interactive Effects Of Elevated Temperature And Co2 On Nitrate, Urea, And Dissolved Inorganic Carbon Uptake By A Coastal California, Usa, Microbial Community, Jl Spackeen, Rachel E. Sipler, K Xu, Et Al, Da Bronk

VIMS Articles

Average global temperatures and carbon dioxide (CO2) levels are expected to increase in the coming decades. Implications for ocean ecosystems include shifts in microbial community structure and subsequent modifications to nutrient pathways. Studying how predicted future temperature and CO2 conditions will impact the biogeochemistry of the ocean is important because of the ocean’s role in regulating global climate. We determined how elevated temperature and CO2 affect uptake rates of nitrate, urea, and dissolved inorganic carbon (DIC) by 2 size classes (0.7-5.0 and >5.0 µm) of a microbial assemblage collected from coastal California, USA. This microbial community was incubated for 10 …


Nitrogen Sources And Net Growth Efficiency Of Zooplankton In Three Amazon River Plume Food Webs, Natalie Loick-Wilde, Sarah C. Weber, Brandon J. Condon, Douglas G. Capone, Victoria J. Coles, Patricia M. Medeiros, Deborah K. Steinberg, Joseph P. Montoya Mar 2016

Nitrogen Sources And Net Growth Efficiency Of Zooplankton In Three Amazon River Plume Food Webs, Natalie Loick-Wilde, Sarah C. Weber, Brandon J. Condon, Douglas G. Capone, Victoria J. Coles, Patricia M. Medeiros, Deborah K. Steinberg, Joseph P. Montoya

VIMS Articles

The plasticity of nitrogen specific net growth efficiency (NGE) in marine mesozooplankton is currently unresolved, with discordant lines of evidence suggesting that NGE is constant, or that it varies with nitrogen source, food availability, and food quality in marine ecosystems. Specifically, the fate of nitrogen from nitrogen fixation is poorly known. We use 15N : 14N ratios in plankton in combination with hydrological data, nutrient profiles, and nitrogen fixation rate measurements to investigate the relationship between new nitrogen sources and the nitrogen specific NGE in three plankton communities along the outer Amazon River plume. The NGE of small …


A Carbon Budget For The Amundsen Sea Polynya, Antarctica: Estimating Net Community Production And Export In A Highly Productive Polar Ecosystem, Pl Yager, Rm Sherrell, Et Al, Rachel E. Sipler, Et Al Jan 2016

A Carbon Budget For The Amundsen Sea Polynya, Antarctica: Estimating Net Community Production And Export In A Highly Productive Polar Ecosystem, Pl Yager, Rm Sherrell, Et Al, Rachel E. Sipler, Et Al

VIMS Articles

Polynyas, or recurring areas of seasonally open water surrounded by sea ice, are foci for energy and material transfer between the atmosphere and the polar ocean. They are also climate sensitive, with both sea ice extent and glacial melt influencing their productivity. The Amundsen Sea Polynya (ASP) is the greenest polynya in the Southern Ocean, with summertime chlorophyll a concentrations exceeding 20 μg L−1. During the Amundsen Sea Polynya International Research Expedition (ASPIRE) in austral summer 2010–11, we aimed to determine the fate of this high algal productivity. We collected water column profiles for total dissolved inorganic carbon (DIC) and …


Regional Differences In Quality Of Krill And Fish As Prey Along The Western Antarctic Peninsula, Kate E. Ruck, Deborah K. Steinberg, Elizabeth A. Canuel Aug 2014

Regional Differences In Quality Of Krill And Fish As Prey Along The Western Antarctic Peninsula, Kate E. Ruck, Deborah K. Steinberg, Elizabeth A. Canuel

VIMS Articles

The warming trend in the northern part of the Western Antarctic Peninsula (WAP) has led to a decrease in perennial and summer sea ice, an increase in heat content over the shelf, and lower phytoplankton biomass, which could affect the prey quality of krill and fish that are utilized by apex predators. We compared prey quality metrics, including elemental (C, N) content; total, neutral, and polar lipid content; and energy densities of known penguin prey items including krill (Euphausia superba, Thysanoessa macrura, and E. crystallorophias) and fish (silverfish Pleuragramma antarcticum and the myctophid Electrona antarctica) …


Long-Term Time-Series Study Of Salp Population Dynamics In The Sargasso Sea, Joshua P. Stone, Deborah K. Steinberg Jan 2014

Long-Term Time-Series Study Of Salp Population Dynamics In The Sargasso Sea, Joshua P. Stone, Deborah K. Steinberg

VIMS Articles

Salps are bloom-forming, pelagic tunicates with high grazing rates on phytoplankton, with the potential to greatly increase vertical particle flux through rapidly sinking fecal pellets. However, the frequency and causes of salp blooms are not well known. We quantified salps from day and night zooplankton net tows in the epipelagic zone of the North Atlantic subtropical gyre as part of the Bermuda Atlantic Time-series Study (BATS). Salp species and size were quantified in biweekly to monthly tows from April 1994 to November 2011. Twenty-one species of salps occurred at the BATS site over this time period, and the most common …


Two Decades Of Pelagic Ecology Of The Western Antarctic Peninsula, Deborah K. Steinberg, D G. Martinson, D P. Costa Jan 2012

Two Decades Of Pelagic Ecology Of The Western Antarctic Peninsula, Deborah K. Steinberg, D G. Martinson, D P. Costa

VIMS Articles

Significant strides in our understanding of the marine pelagic ecosystem of the Western Antarctic Peninsula (WAP) region have been made over the past two decades, resulting from research conducted aboard ARSV Laurence M. Gould and RVIB Nathaniel B. Palmer. These advances range from an understanding of the physical forcing on biology, to food web ecology (from microbes to top predators), to biogeochemical cycling, often in the larger context of rapid climate warming in the region. The proximity of the WAP to the Antarctic Circumpolar Current and WAP continental shelf bathymetry affects the hydrography and helps structure the biological community. Seasonal, …


Synergistic Effects Of Iron And Temperature On Antarctic Phytoplankton And Microzooplankton Assemblages, J. M. Rose, Y. Feng, Et Al, Walker O. Smith Jr., B. Sigist, S. Tozzi, Et Al Jan 2009

Synergistic Effects Of Iron And Temperature On Antarctic Phytoplankton And Microzooplankton Assemblages, J. M. Rose, Y. Feng, Et Al, Walker O. Smith Jr., B. Sigist, S. Tozzi, Et Al

VIMS Articles

Iron availability and temperature are important limiting factors for the biota in many areas of the world ocean, and both have been predicted to change in future climate scenarios. However, the impacts of combined changes in these two key factors on microbial trophic dynamics and nutrient cycling are unknown. We examined the relative effects of iron addition (+1 nM) and increased temperature (+4 degrees C) on plankton assemblages of the Ross Sea, Antarctica, a region characterized by annual algal blooms and an active microbial community. Increased iron and temperature individually had consistently significant but relatively minor positive effects on total …


The Microbial And Metazoan Community Associated With Colonies Of Trichodesmium Spp.: A Quantitative Survey, Cc Sheridan, Deborah K. Steinberg, Gw Kling Sep 2002

The Microbial And Metazoan Community Associated With Colonies Of Trichodesmium Spp.: A Quantitative Survey, Cc Sheridan, Deborah K. Steinberg, Gw Kling

VIMS Articles

Association with resource-rich particles may benefit a number of planktonic species in oligotriphic, open-ocean regimes. This study examined communities of microbes and Zooplankton associated with colonies of the cyanobacterium Trichodesmium spp. in the Sargasso Sea. Trichodesmium colonies and seawater controls were collected near Bermuda using SCUBA during September 1995, and June, July and August 1996. Organisms associated with the colonies and those in the surrounding seawater were enumerated using light and fluorescence microscopy. We found that 85% of the Trichodesmium puff and tuft colonies examined harbored associated organisms. Associated organisms included bacteria (rod and coccoid),fungi, pennate diatoms, centric diatoms, heterotrophic …


Phytoplankton Growth Rates In The Ross Sea, Antarctica, Determined By Independent Methods: Temporal Variations, Walker O. Smith Jr., D. M. Nelson, S. Mathot Jan 1999

Phytoplankton Growth Rates In The Ross Sea, Antarctica, Determined By Independent Methods: Temporal Variations, Walker O. Smith Jr., D. M. Nelson, S. Mathot

VIMS Articles

The development of the seasonal phytoplankton bloom in the Ross Sea was studied during two cruises. The first, conducted in November-December 1994, investigated the initiation and rapid growth of the bloom, whereas the second (December 1995-January 1996) concentrated on the bloom's maximum biomass period and the subsequent decline in biomass. Central to the understanding of the controls of growth and the summer decline of the bloom is a quantitative assessment of the growth rate of phytoplankton. Growth rates were estimated over two time scales with different methods. The first estimated daily growth rates from isotopic incorporation under simulated in situ …


Phenotypic Selection In An Intertidal Snail: Effects Of A Catastrophic Storm, G. Trussell May 1997

Phenotypic Selection In An Intertidal Snail: Effects Of A Catastrophic Storm, G. Trussell

VIMS Articles

Littorina obtusata exhibits clear morphological variation (e.g. shell height, shell length, and aperture area) among shores differentially exposed to wave energies. Selection imposed by the hydrodynamic environment is often invoked to explain the correlation between morphology and wave exposure in intertidal organisms, but rarely is this hypothesis tested. I examined the effects of a catastrophic storm on the shell length and relative shell height and aperture area of L. obtusata populations on 2 protected and 1 wave-exposed share in New England (USA) to test this hypothesis. Snails sampled after the storm had relatively squatter shells than those sampled before the …


Mid‐Level Intrusions At The Continental Shelf Edge, Christopher S. Welch Nov 1981

Mid‐Level Intrusions At The Continental Shelf Edge, Christopher S. Welch

VIMS Articles

Observations across the continental shelf offshore from New Jersey in late summer 1976 show an intrusion of saline water at the mid level of the water column across the shelf edge front, which appears in density only as an offshore thickening of the pycnocline. This internal density field produces horizontal pressure gradient forces within the pycnocline in the onshore direction. These forces, in the linearized equation of motion with a constant eddy viscosity, drive a circulation which resembles a double Ekman spiral for internal pressure vertical distributions which are thin with respect to the Ekman depth. For thick pressure distributions, …