Digital Commons Network^™

Phytoplankton In The Aqueous Ecological Theater: Changing Conditions, Biodiversity, And Evolving Ecological Concepts, Patricia M. Glibert

Journal of Marine Research

Phytoplankton communities, from lakes to oceans, are changing with anthropogenic nutrient loading and climate change. So, too, are the tools by which phytoplankton are quantified and characterized, yielding a torrent of new data and new types of data that can be related to ecosystem function. New insights have been gained about the physiology of resource acquisition by phytoplankton, allowing new relationships between phytoplankton biodiversity and function to be developed. Despite years of emphasis on the use of inorganic substrates in support of phytoplankton nutrition, it is now well understood that phytoplankton rely on a broad suite of substrates, both dissolved …

A Metapopulation Model For Whale-Fall Specialists: The Largest Whales Are Essential To Prevent Species Extinctions, Craig R. Smith, Joe Roman, J. B. Nation

Journal of Marine Research

The sunken carcasses of great whales (i.e., whale falls) provide an important deep-sea habitat for more than 100 species that may be considered whale-fall specialists. Commercial whaling has reduced the abundance and size of whales, and thus whale-fall habitats, as great whales were hunted and removed from the oceans, often to near extinction. In this article, we use a metapopulation modeling approach to explore the consequences of whaling to the abundance and persistence of whale-fall habitats in the deep sea and to the potential for extinction of whale-fall specialists. Our modeling indicates that the persistence of metapopulations of whale-fall specialists …

Estimating Particle Export Fl Ux From Satellite Observations: Challenges Associated With Spatial And Temporal Decoupling Of Production And Export, Dennis J. Mcgillicuddy Jr., Laure Resplandy, Marina Lévy

Journal of Marine Research

Recent studies have suggested that accurate predictions of particle export flux can be derived from satellite-based estimates of phytoplankton biomass and net primary production (NPP), combined with models of the food web. We evaluate the performance of this approach using the output of a highresolution, basin-scale coupled physical-biogeochemical model. There is tight correlation between the annual mean export flux simulated by the biogeochemical model and that predicted by the satellitebased algorithm driven by NPP from the model. Although the satellite-based approach performs well on the annual average, there are significant departures during the course of the year, particularly in spring. …

Recirculating Flow In A Basin With Closed F/H Contours, Alexander M. Fuller, Thomas W. N. Haine, Erik Kvaleberg

Journal of Marine Research

A general circulation model is used to study the time evolution of a rotating, weakly baroclinic fluid in a basin with sloping sidewalls. Contours of f/h, where f is the Coriolis parameter and h is the depth of the fluid, are closed in this model. The fluid is forced by a localized source of positive vorticity. The initial response is a narrow, recirculating cell that resembles a β-plume modified by bathymetry. Such cells have been found in previous studies and have been linked to the recirculation cells observed in the subpolar North Atlantic. However, this is not a steady …

Jim Mccarthy’S Achievements At The Intersection Of Science With Public Policy, John P. Holdren

Journal of Marine Research

Along with his distinguished research career as a biological oceanographer and marine biologist and his inspiring service as a teacher, advisor, and mentor to students and junior colleagues at Harvard University, Jim McCarthy has been a scientific statesman of the first order, bringing insights from his research and his deep understanding of the role of science in society into the arenas of management of scientific enterprises and public and policy-maker education about the science relating to some of the greatest challenges of our time. His roles at the intersection of science with public issues have included stints as director of …

Hats Off To You, Jim!, Bill Boicourt, Doug Capone, Ed Carpenter, Penny Chisholm, Paul Falkowski, Jim Galloway, Dave Kirchman, Fred Lipschultz, Hal Mooney, François Morel, John Nevins, Mike Roman, Dan Schrag, Sybil Seitzinger, Bess Ward

Journal of Marine Research

Jim’s intellectual curiosity was an inspiration. In addition to those whose comments follow, he clearly touched the careers and lives of many others.

The Microbial Loop Concept: A History, 1930–1974, Peter J. Le B. Williams, Hugh W. Ducklow

Journal of Marine Research

The microbial loop as a leading concept in marine microbiology gained wide recognition in the 1980s, but it has roots extending back to the 1930s when microbiologists first began to take a more dynamic approach to investigating the roles of bacteria in ocean food webs and biogeochemical cycles. Here we present a history of the microbial loop concept with emphasis on the period starting in 1930, when marine bacteriologists in Russia and the West began to study explicitly the roles of marine bacteria in the sea. Selman Waksman at Woods Hole and Claude ZoBell at La Jolla relied on colony …

The Ecological And Biogeochemical State Of The North Pacifi C Subtropical Gyre Is Linked To Sea Surface Height, Benedetto Barone, Ashley R. Coenen, Stephen J. Beckett, Dennis J. Mcgillicuddy Jr., Joshua S. Weitz, David M. Karl

Journal of Marine Research

Sea surface height (SSH) is routinely measured from satellites and used to infer ocean currents, including eddies, that affect the distribution of organisms and substances in the ocean. SSH not only reflects the dynamics of the surface layer, but also is sensitive to the fluctuations of the main pycnocline; thus it is linked to events of nutrient upwelling. Beyond episodic upwelling events, it is not clear if and how SSH is linked to broader changes in the biogeochemical state of marine ecosystems. Our analysis of 23 years of satellite observations and biogeochemical measurements from the North Pacific Subtropical Gyre shows …

Bioaccumulation Of Heavy Metals In Mesozooplankton From A Human-Impacted South Western Atlantic Estuary (Argentina), Diana M. Villagran, Melisa D. Fernández Severini, Florencia Biancalana, Carla V. Spetter, Eleonora M. Fernández, Jorge E. Macrovecchio

Journal of Marine Research

The total metal concentrations (Cd, Cu, Pb, Zn, Mn, Ni, Cr, and Fe) in the mesozooplankton (200 μm–2 mm) were studied for a year in a human-impacted estuary strongly affected by urban and industrial discharges located in the South Atlantic. Over the last 25 years, this estuary has been the site of significant anthropogenic impacts including industrial activities, maritime traffic, and regular dredging. A quantitative and qualitative analysis was also carried out to identify the mesozooplanktonic community that was sampled for metal determinations. The mesozooplankton had high concentrations of toxic metals such as Cd, Pb, Cr, and Ni, which may …

Secrets Of The Deep: Defining Privacy Underwater, Annie Brett

UF Law Faculty Publications

The drones are coming, But not just to your neighborhood skies – to the world’s oceans. From recreational robots designed to autonomously follow divers and record video of them to low-cost, remotely operated submersibles that put ocean exploration in the hands of the general public to sophisticated military submersibles able to autonomously gather intelligence throughout the oceans, the underwater drone market is exploding. But unlike on land, this explosion has not been accompanied by similar discussion of privacy concerns. Instead, the ocean’s rapid shift away from an inaccessible operational sanctuary is one that is happening largely silently. And it is …

2019 Conference - “Biodiversity Beyond National Jurisdiction: Intractable Challenges & Potential Solutions”: Program, Center For Oceans Law & Policy

Conference on Oceans Law & Policy

Tuesday, May 14, 2019 to Thursday, May 16, 2019 | World Maritime University, Sasakawa Auditorium, Malmö, Sweden

The conference discussed the development of an internationally legally binding instrument under UNCLOS on the conservation and sustainable use of marine biological diversity of areas beyond national jurisdiction (BBNJ). Our 43rd Annual Conference was co-organized with the World Maritime University--Sasakawa Global Ocean Institute at the World Maritime University and the Nippon Foundation.

Purchase Conference Proceedings Volume.

The Effects Of Kt ≠ Ks In A Stommel-Like Model Of The Upper Atlantic Meridional Overturning Circulation Under Steady Surface Flux Forcing, A. E. Gargett

Journal of Marine Research

This study examines a simple 6-box model of a single pole-to-pole ocean basin. Each of a northern "polar gyre," a southern "polar gyre," and an "equatorial gyre," consisting of north and south subtropical gyres plus the equatorial region, is represented by two boxes: a surface box receiving constant fluxes of both temperature (heat) and salt (freshwater) and a deep box. The model includes four dominant processes: surface flux forcing, horizontal meridional advection driven by Southern Ocean winds, horizontal eddy diffusion at gyre boundaries, and convection, as well as the process of vertical diffusion by small-scale processes. Provided that heat loss …

Amazon River Infl Uence On Nitrogen Fi Xation In The Western Tropical North Atlantic, Joseph P. Montoya, Jason P. Landrum, Sarah C. Weber

Journal of Marine Research

We measured rates of N- and C-fixation with a direct tracer method in regions of the western tropical North Atlantic influenced by the Amazon River plume during the high flow period of 2010 (May–June 2010). We found distinct regional variations in N-fixation activity, with the lowest rates in the plume proper and the highest rates in the plume margins and in offshore waters. A comparison of our N- and C-fixation measurements showed that the relative contribution of N-fixation to total primary production increased from the plume core toward oceanic waters, and that most of the C-fixation in this system was …

Synthesis Report: Defining Thresholds And Indicators Of Primary Producer Response To Dredging-Related Pressures: Report Of Theme 5 Prepared For The Dredging Science Node, Paul Lavery, Kathryn Mcmahon, John Statton, Mat Vanderklift, Simone Strydom, Gary Kendrick

Research outputs 2014 to 2021

Seagrasses form a small component of a diverse group of organisms termed ‘benthic primary producers’. Benthic primary producers are organisms that grow on the sea-bed that obtain some or all of their energy needs from photosynthesis. This includes animals such as scleractinian corals and some sponges that host microscopic intercellular algae, coralline and turf algae, and the larger seaweeds such as the kelps and sargassum. Seagrasses are marine flowering plants, more closely related to land plants than seaweeds and algae. Seagrasses live mostly in soft sediments, and can be found from the shallow intertidal zone through to a depth of …

Threats To Ocean Biodiversity, Allia Lin '20, Grace Wulffraat '20

UN Sustainable Development Goals Infographics

Overfishing

Taking fish out of the ocean faster than their populations can be naturally replenished

Hydrothermal Stamp On The Oceans, Susan Q. Lang

Faculty Publications

The composition of the oceans is altered by hydrothermal circulation. These chemical factories sustain microbial life, which in turn alters the chemistry of the fuids that enter the ocean. A decade of research details this complex interchange.

Rectified Flow In A Stratified Coastal Ocean, K. H. Brink

Journal of Marine Research

An idealized numerical model is used to explore the generation of mean flows by oscillating wind forcing in a stratified coastal ocean with no alongshore variability, i.e., where neither barotropic nor baroclinic instability is a factor. On the inner shelf, where surface-to-bottom mixing occurs, a mean cross-shelf flow develops, as examined by Castelao et al. (2010), and the present results suggest that this flow can remain two-dimensional if there is a nonzero cross-shelf density gradient. Offshore of the inner shelf, where the water column is stratified, a mean alongshore flow develops in the direction opposite to coastal-trapped wave propagation. This …

Antarctic Mode Water, K. Speer, J.-B. Sallee, V. Pellichero

Journal of Marine Research

An estimate of Southern Ocean volume in temperature-salinity (T-S) classes is made with a focus on cold water masses south of the Polar Front, at depths shallower than 2,000 m. The volumetric diagram for waters below 5^° C shows a deficit at temperatures near 0^° C and 34.2 psu, surrounded by a ring of larger volumes, related to water mass formation near the Polar Front and near the continental margins as well as mixing effects. The cold, fresh extreme of the Antarctic Intermediate Water T-S relation shows a volumetric maximum, apparently distinct from the interior T-S relationship. We …

Multi-Decadal Trends And Variability In Temperature And Salinity In The Mid-Atlantic Bight, Georges Bank, And Gulf Of Maine, Elizabeth J. Wallace, Lev B. Looney, Donglai Gong

Journal of Marine Research

Increasing attention is being placed on the regional impact of climate change. This study focuses on the decadal scale variabilities of temperature and salinity in the Mid-Atlantic Bight (MAB), Georges Bank (GB), and Gulf of Maine (GOM) from 1977 to 2016 using hydrographic survey data from the National Oceanic and Atmospheric Administration (NOAA) Northeast Fisheries Science Center. The MAB (as defined by the shelf regions from Cape Hatteras to Cape Cod) experienced warming rates of 0.57 °C per decade during the Winter/Spring season (Jan–Apr) and 0.47 °C per decade during the Fall/Winter season (Sep–Dec). The GOM and GB, on the …

Chemical And Phycological Structure Of Surface Microlayer And Subsurface Water In A Southern Baltic Sea Estuary, Józef Piotr Antonowicz, Anna Kozak

Journal of Marine Research

The surface microlayer of water (SML) is a unique ecotone found on all water bodies. It is an interphase for the exchange of matter between the hydrosphere and the atmosphere. This ecotone is capable of accumulating chemicals and microorganisms in amounts as high as 100-fold greater than those observed in the pelagic zone. Here we report on the accumulation of chemicals and phytoneuston in the SML of the estuarial Łebsko Lake located at the southern coast of the Baltic Sea in the unpolluted region of the World Biosphere Reserve: the Słowínski National Park in Poland. The physicochemical parameters and phytoplankton …

Lagrangian Dispersion Characteristics In The Western Mediterranean, Maher Bouzaiene, Milena Menna, Pierre-Marie Poulain, Dalila Elhmaidi

Journal of Marine Research

Dispersion characteristics in the Western Mediterranean are analyzed using data from Coastal Ocean Dynamics Experiment (CODE) and Surface Velocity Program (SVP) surface drifters deployed in the period 1986–2017. Results are presented in terms of absolute dispersion A² (mean-squared displacement of drifter individuals) and of relative dispersion (D²; mean square separation distance of drifter pairs). Moreover, the dispersion characteristics are estimated for different initial separation distances (D₀) between particles: smaller, larger, or comparable with the internal Rossby radius of deformation. Results show the presence of a quasiballistic regime for absolute dispersion at small time scales and …

Why Is The Ocean Surface Slightly Warmer Than The Atmosphere?, Lakshika Girihagama, Doron Nof

Journal of Marine Research

How much warmer is the ocean surface than the atmosphere directly above it? The present study offers a means to quantify this temperature difference using a conceptual nonlinear one-dimensional global energy balance coupled ocean–atmosphere model ("Aqua Planet"). The significance of our idealized model, which is of intermediate complexity, is its ability to obtain an analytical solution for the global average temperatures. Our analytical model results show that, for the present climate, predicted global mean ocean temperature is 291.1 K whereas surface atmospheric temperature above the ocean surface is 287.4 K. Thus, the modeled surface ocean is 3.7 K …

High-Frequency Variability In The North Icelandic Jet, B. E. Harden, R. S. Pickart

Journal of Marine Research

We describe the high-frequency variability in the North Icelandic Jet (NIJ) on the Iceland Slope using data from the densely instrumented Kögur mooring array deployed upstream of the Denmark Strait sill from September 2011 to July 2012. Significant sub-8-day variability is ubiquitous in all moorings from the Iceland slope with a dominant period of 3.6 days. We attribute this variability to topographic Rossby waves on the Iceland slope with a wavelength of 62 ± 3 km and a phase velocity of 17.3 ± 0.8 km/day^–1 directed downslope (–9° relative to true-north). We test the theoretical dispersion relation for these …

Introduction To The 10th Marine Law Symposium, Julia B. Wyman

Law Faculty Scholarship

No abstract provided.

Sediment Burial Stress Response, Bio-Indicators And Thresholds For A Tropical Multi-Species Seagrass Assemblage: Report Of Theme 5 - Project 5.5.2 Prepared For The Dredging Science Node, John Statton, Kathryn Mcmahon, Roisin Mccallum, Gary Kendrick, Paul Lavery

Research outputs 2014 to 2021

Deterioration in water clarity by resuspension of dredged sediments is presumed to be a major mechanism by which dredging can impact seagrasses. This report presents findings from a controlled light experiment that aimed to determine the effects of low light stress on the growth of three seagrass species found in the northwest of Western Australia.

Aims

• To determine the effects of sediment burial stress under dredge-simulated conditions on the growth and health of three seagrass species found in the northwest of Western Australia.
• Provide guidance and protocols for the application of the research outputs (e.g. seagrass burial stress:response relationships, sub-lethal …

Presentation, Matt Niemiro '20, Micah Casey-Fusco '20

Living Green

No abstract provided.

Macrobenthos Community Succession In The Northern Gulf Of Mexico Hypoxic Regions: Testing The Pearson-Rosenberg Model, Shivakumar K. Shivarudrappa, Kevin B. Briggs

Journal of Marine Research

The Pearson and Rosenberg (P-R) conceptual model of macrobenthic succession was used to assess the impact of hypoxia (dissolved oxygen concentration ≤2 mg L^–1) on the macrobenthic community on the continental shelf of the northern Gulf of Mexico. The stress-response relationship between bottom-water oxygen concentration and the macrobenthic community was used to determine the ecological condition of the benthic habitat. In lieu of testing the effect of decreasing influence of organic enrichment on the macrobenthic community as a function of distance from the source of organic pollution, we tested the effect of bottom-water dissolved oxygen concentration as a …

The Sea: The Science Of Ocean Prediction, Nadia Pinardi, Pierre F. J. Lermusiaux, Kenneth H. Brink, Ruth H. Preller

Journal of Marine Research

At the beginning of the 20th century Vilhelm Bjerknes defined the “ultimate problem ofmeteorology and hydrography” as the discovery of “the laws according to which an atmospheric or hydrospheric state develops out of the preceding one” and the “precalculation of future states” from gridded analyzed observations—that is, forecasting. The development of the electronic computer and the vision of several meteorologists allowed the transformation of meteorology into a sophisticated scientific discipline based on physics and mathematics. The first successful meteorological forecast was carried out in the 1950s. Meteorological forecasting became an operational activity at the end of the 1960s. The contributions …

Some Considerations About Coastal Ocean Observing Systems, K. H. Brink, Anthony R. Kirincich

Journal of Marine Research

Coastal ocean observing capabilities are evolving rapidly, both in terms of sensors and in terms of the volume of information available. We discuss the aspects of the coastal ocean that make it a unique environment, both in terms of physical processes and measurement techniques. Although many global-level systems are relevant to the coastal ocean, we concentrate on treating systems that are unique to the continental shelf environment. Further, we briefly discuss examples of measurement systems that would be useful for developing and driving ocean prediction systems.

Langmuir Supercells On The Middle Shelf Of The South Atlantic Bight: 1. Cell Structure, D. K. Savidge, A. E. Gargett

Journal of Marine Research

Langmuir circulation cells extending through entire water columns exert a profound influence on sediment transport on shallow shelves, hence their designation as "Langmuir Supercells" (LSs) upon discovery in 2004 in water of 15 m depth at the Long-Term Ecosystem Observatory (LEO) off New Jersey (United States). Until now, similar high-frequency, full water column measurements of turbulent velocities and density fields have not been reported from significantly deeper continental shelf environments. Such deeper measurements are needed to determine whether LSs exist to influence sediment transport outside the inner shelf. In this article, that deficiency is addressed, using measurements from a midshelf …