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This article examines the role of swimming animals in ocean mixing. While it was previously believed that animal locomotion had little impact on ocean mixing, recent research suggests otherwise. Laboratory experiments with brine shrimp and field observations of krill aggregations indicate that swimming animals can contribute to ocean mixing at higher rates than previously thought. However, studying the effects of marine organisms on ocean mixing is challenging due to the vastness of the ocean and avoidance behaviors triggered by measurement instruments. The article proposes using magnetic signatures or environmental DNA to indirectly detect and quantify ocean mixing. Additionally, the development of bio-hybrid robotic devices inspired by jellyfish swimming capabilities is discussed as a means of exploring and measuring the ocean. The ultimate goal is to better understand the biogeochemical consequences of animal swimming and their impact on the ocean. [Extracted from the article]

The National Oceanographic Partnership Program (NOPP) is a grant program offered by the Defense Department's Office of Naval Research. The program aims to improve knowledge of the ocean in order to promote national security, economic development, quality of life, and science education and communication. The program is open to colleges and universities, for-profit organizations, and state, local, and Native American tribal governments. The program has two specific research topics of interest: a global multi-agency experiment on internal wave energy and interactions in the ocean, and the design and demonstration of low-cost, air deployable 400m profiling CTD floats for investigating sub-mesoscale eddies. The deadline for applications is November 22, 2023, and a total of $23 million in funding is expected to be awarded over three years. More information can be found at www.grants.gov. [Extracted from the article]

This article from American Scientist explores the idea that small organisms and molecules can have a significant impact on their surroundings. The author discusses how swarms of zooplankton in the ocean can produce effects that exceed the size of any individual in the group, leading to extensive mixing of ocean waters and potential implications for nutrient distribution and climate change. The article also examines research on the swimming efficiency of trout and its implications for the design of underwater vehicles. Additionally, the article delves into the process of directed evolution, where scientists can tailor the function of proteins and RNA through iterative steps and genetic editing. The author encourages readers to share their own examples of how small changes or advances can make a larger difference in research work. [Extracted from the article]

Jusant, a climbing game developed by JUSANT, focuses on the fundamentals of climbing and provides a realistic experience. The game involves scaling cliff faces using a combination of free climbing and line climbing. Players can grip handholds using the triggers on a gamepad and navigate their way up the cliff. Jusant also incorporates additional abilities like double jumps and magical plants as handholds. The game's emphasis on manual climbing actions and its ability to capture a rhythm similar to real climbing sets it apart from other climbing games. Despite being developed by the studio behind the narrative adventure Life Is Strange series, Jusant offers a unique and satisfying climbing experience. [Extracted from the article]

SHOALS of breeding anchovies may be stirring the ocean off the coast of Spain. Ocean mixing is largely thought to be controlled by wind and tidal energy, but neither factor could explain this night-time rise, says Fernández Castro. [Extracted from the article]

Scientists have discovered a previously unknown water mass in the Atlantic Ocean called the Atlantic Equatorial Water. This gigantic body of water stretches from Brazil to West Africa and forms along the equator as ocean currents mix separate bodies of water to the north and south. The discovery of this water mass completes the phenomenological pattern of basic water masses in the world ocean. The finding will provide scientists with a better understanding of the ocean's mixing processes and its role in transporting heat, oxygen, and nutrients globally. [Extracted from the article]

Supplied Adele Morrison's work has revealed the ongoing impact ofwarm ocean currents on Antarctic ice melt. Greg Shirah/NASA Scientific Visualisation Studio This year, Australia's prestigious Prime Minister's Prize forScience has been awarded to a physical oceanographer whosework has had a "transformative impact" on our understandingof Earth's oceans. [Extracted from the article]

Instability and lateral eddy fluxes associated with a tidal mixing front are studied using idealized primitive equation numerical model runs. The front itself develops as a result of turbulence associ-ated with imposed tidal currents over a sloping bottom. Thus, the model includes realistic levels of turbulence and time-dependence in the base-state conditions. In all of the 21 configurations consid-ered, the front is unstable to fluctuations that usually draw energy primarily from the potential energy pool. Scalings are developed to parameterize a) the location of the tidal mixing front; b) the eddy kinetic energy; and c) the lateral eddy coefficients. In all cases, baroclinic instability enhances the lateral mixing relative to the two-dimensional case, but the extent of enhancement varies with the input parameters. Preliminary model runs that include a simple nutrient-phytoplankton-zooplankton-detritus biological model do not suggest any substantial ecological effect of the baroclinic instabilities. The lack of a strong biological effect, despite the enhanced eddy transports, occurs because of the near cancelation of oppositely directed cross-isobath eddy fluxes in the upper and lower parts of the water column. Similarly, shallow and deep cross-frontal eddy heat fluxes also nearly balance: this cancelation appears to help explain how the classical one-dimensional potential energy criterion for frontal location can work so well in a complex ocean [ABSTRACT FROM AUTHOR]

Ocean mixing is thought to control the climatically important oceanic overturning circulation. Here we argue the marine biosphere, by a mechanism like the bioturbation occurring in marine sediments, mixes the oceans as effectively as the winds and tides. This statement is derived ultimately from an estimated 62.7 TeraWatts of chemical power provided to the marine environment in net primary production. Various approaches argue something like 1% (.63 TeraWatts) of this power is invested in aphotic ocean mechanical energy, a rate comparable to wind and tidal inputs. [ABSTRACT FROM AUTHOR]

This paper introduces a Bayesian inversion approach to estimating steady state ocean circulation and tracer fields. It is based on a quasi-horizontal flow model and a PDE solver for the forward problem of computing solutions to the tracer field advection-diffusion equations. A typical feature of existing ocean circulation inverse methods is a preprocessing stage in which the tracer data are interpolated over a regular grid and the interpolation error is ignored in the subsequent inversion. Our approach only uses interpolated data at those grid points that have neighboring hydrographic stations. By exploiting physically-based models in an integrated fashion, the method provides a statistically unified inversion and tracer field reconstruction with minimal data smoothing. Solving the problem consists of finding information about the circulation and tracer fields in the presence of a number of assumptions (prior information); the resulting posterior probability distribution summarizes what we can know about these fields. We develop a Markov chain Monte Carlo simulation procedure to extract information from the (analytically intractable) posterior distribution of all the parameters in the model; uncertainty about the "solution" is represented by variation in the output of the simulation runs. Our approach is aimed at finding the time-averaged quasi-horizontal flow and tracer fields for an abyssal neutral density layer in the South Atlantic. [ABSTRACT FROM AUTHOR]

A monitoring system for the meridional overtuming circulation (MOC) is deployed into an "eddy-permitting" numerical model (FLAME) at three different latitudes in the North Atlantic Ocean. The MOC is estimated by adding contributions related to Ekman transports to those associated with the zonally integrated vertical velocity shear. Ekman transports are inferred from surface wind stress, whereas the velocity shear is derived from continuous density "observations," principally near the eastern and western boundaries, employing thermal wind balance. The objective is to test the method and array setups for possible real observation in the ocean at the chosen latitudes and to guide similar tests at different latitudes. Different "mooring placements" are tested, ranging from a minimal setup to the theoretical maximum number of "measurements." A relatively small number of vertical density profiles (about 10, the exact number depending on the latitude) can achieve a reconstruction of the MOC similar to one achieved by any larger number of profiles. However, the main characteristics of the MOC can only be reproduced at latitudes where bottom velocities are small, here at 26N and 36N. For high bottom velocities, in FLAME at 53N, the array fails to reproduce the strength and variability of the MOC because the depth-averaged flow cannot be reconstructed accurately. In FLAME, knowledge of the complete bottom velocity field could substitute for the knowledge of the depth-averaged velocity field. [ABSTRACT FROM AUTHOR]

Mixing in the ocean is usually accompanied by a net reduction in volume caused by the nonlinear nature of the equation of state. This contraction-on-mixing at a certain depth implies that the whole water column above this depth slumps a little and so suffers a reduction in gravitational potential energy. Under certain circumstances the gravitational potential energy of the entire water column can decrease as a consequence of mixing activity at a certain depth. We examine Fofonoff's hypothesis that in these circumstances the net reduction of gravitational potential energy of the whole water column causes a local increase in the turbulent mixing activity at the location of the original mixing. Fofonoff proposed that this increased local mixing diffuses the local property gradients until the criterion for positive feedback is no longer satisfied, so providing an upper bound for the vertical stratification in the ocean. Bearing in mind the relatively inefficient nature of turbulent mixing at causing diapycnal fluxes (the majority of the turbulent kinetic energy goes directly into internal energy), we find that the criterion for positive feedback is a factor of approximately seven more difficult to achieve than has been realized to date. An examination of oceanic data shows that while Fofonoff's original criterion for positive feedback is often exceeded, the more appropriate criterion is almost never approached. The positive feedback hypothesis assumes that the reduction in the gravitational potential energy of the whole water column appears at the location of the original mixing as an increase in the turbulent mixing activity. We show that this very focused oceanic response is extremely difficult to justify. For example there is no such feedback in a strictly one-dimensional water column; rather all of the reduction in gravitational potential energy appears as an increase in internal energy at the depth of the original mixing and there is no possibility of any positive feedback to increase the turbulent mixing. As the positive feedback hypothesis is lacking a convincing theoretical basis and is not supported by oceanic data, we do not believe that it acts as an effective upper bound on oceanic stratification. [ABSTRACT FROM AUTHOR]

We address the problem of the multiple equilibria of the thermohaline circulation in a hierarchy of models. The understanding of the relation between bifurcation diagrams of box models, twodimensional models and those of a global ocean general circulation model, is facilitated through analysis of the equilibrium solutions of a three-dimensional Atlantic-like sector model with an open southern channel. Using this configuration, the subtle effects of the wind-stress field, the effects of continental asymmetry and the asymmetry in the surface freshwater flux can be systematically studied. The results clarify why there is an asymmetric Atlantic circulation under a near equatoriallysymmetric buoyancy forcing. They also lead to an explanation of the hysteresis regime that is found in models of the global ocean circulation. Both explanations are crucial elements to understanding the role of the ocean in past and future climate changes. [ABSTRACT FROM AUTHOR]

The article discusses the ocean-oxygen depleting effects of climate change and reduced oxygen concentrations at deep ocean elevations. As a consequence, fish and other marine life can be left with insufficient oxygen. Woods Hole Oceanographic Institution oceanographer Scott Doney is cited regarding so-called ocean oxygen minimum zones. Sluggish mixing of oxygen and nutrients in ocean layers is discussed. Physical oceanographer Lothar Stramma is cited regarding a study of the rate of ocean oxygen depletion.

Examines tidal mixing, internal wave bores, and cross-bank particle transport over a finite amplitude asymmetric bank. Utilization of a two-dimensional primitive equation ocean model with Mellor and Yamada turbulent closure; Kinematics of cross-frontal water exchange over Georges Bank.

Examines the salinity distribution of the Mediterranean Waters in the eastern North Atlantic. Pronounced thermohaline front of Labrador Sea water; Diffusion equation of salinity; Mean trajectories of meddies; Features of the simplified unidirectional mixing model aimed to diagnose basic parameters of mesoscale structures.

The article offers information on how turbulence from small animals, such as krill and brine shrimp, could distribute nutrients in the ocean. Additional topics discussed include how swarms of these animals may be capable of mixing ocean layers, insights from John Dabiri, an expert in fluid dynamics, and how ocean mixing is an important part of the global climate cycle.

The article discusses the environmental and economic impacts of El Niño phenomenon around the world. El Niño is the abnormal warming of surface ocean waters or the disruption of normal climatic patterns. Some of the reported consequences include the bush fire in South Australia in 1983 and the unusual flooding in Texas in the winter of 1991-1992.

The article reports that California yesterday announced the first boundary for a new system of marine protected areas (MPAs) along its central coast. At a meeting in Pasadena, stakeholders agreed on a region in state waters about 300-kilometers long — stretching from a point just north of Santa Cruz to a point just north of Santa Barbara — within which the parcels of sea would be partially closed to fishing. Eventually, many such regions — each dotted with no-take zones — would span the state's coast. In 1999, California tried to address the problem with the Marine Life Protection Act (MLPA). One of MLPA's requirements was to create a network of MPAs along the state's coastline. The key feature of the new reserves is that they will be naturally connected: endangered larvae can ride the ocean currents from one reserve to another.

The article offers information on a research by researcher Andrew Watson and others of University of Exeter, which discusses the phenomenon of ocean mixing by releasing an inert chemical tracer in to the Southeast Pacific and reflects on its importance in understanding the overall climate system.

This article reports on the expected landing of an armada of rubber toys on the British shoreline. The toys were part of a cargo lost from a ship in 1999 and they have been riding the ocean currents ever since. Some have already washed up in Sitka, Alaska and there have been sightings from Hawaii, Russia, Scotland and Maine. The impact on science from this spill has been notable as it has allowed a tracking of currents that was not possible before.

The article states that the movements of Pacific krill in the Saanich Inlet on the coast of Vancouver Island in British Columbia, Canada increases water turbulence. Researcher Eric Kunze states that this is the first measurement of a creature's contribution to ocean mixing. Turbulence drives many ocean events with global implications, such as gas exchange between the atmosphere and water.

Focuses on a report presented by Joel Cline and Richard Gammon at a American Geophysical Union meeting on the use of chlorofluorocarbon-11 and chlorofluorocarbon-12 gases in tracing ocean mixing and circulation. Advantages of chlorofluorocarbons over tritium, a radioactive substance more commonly used as a tracer; Efforts to incorporate measurements of chlorofluorocarbons into existing procedures.