Search research articles

ABOUT JoVE

Overview Leadership Blog JoVE Help Center

AUTHORS

Publishing Process Editorial Board Scope & Policies Peer Review FAQ Submit

LIBRARIANS

Testimonials Subscriptions Access Resources Library Advisory Board FAQ

RESEARCH

JoVE Journal Methods Collections JoVE Encyclopedia of Experiments Archive

EDUCATION

JoVE Core JoVE Business JoVE Science Education JoVE Lab Manual Faculty Resource Center Faculty Site

Terms & Conditions of Use

Related Concept Videos

What are Biogeochemical Cycles?

What are Biogeochemical Cycles?

The most common elements in organic molecules, carbon, hydrogen, oxygen, nitrogen, sulfur, and phosphorus, are only available in the ecosystem in limited amounts. Therefore, these nutrients must be recycled through both biotic and abiotic components of the ecosystem, in processes generally called biogeochemical cycles.

The Water Cycle

The Water Cycle

The Earth’s hydrosphere includes all of the areas where the storage and movement of water occurs. Since water is the basis of all living processes, the cycling of water is extremely important to ecosystem dynamics.

The Phosphorus Cycle

The Phosphorus Cycle

Unlike carbon, water, and nitrogen, phosphorus is not present in the atmosphere as a gas. Instead, most phosphorus in the ecosystem exists as compounds, such as phosphate ions (PO43-), found in soil, water, sediment and rocks. Phosphorus is often a limiting nutrient (i.e., in short supply). Consequently, phosphorus is added to most agricultural fertilizers, which can cause environmental problems related to runoff in aquatic ecosystems.

The Nitrogen Cycle

The Nitrogen Cycle

Nitrogen atoms, present in all proteins and DNA, are recycled between abiotic and biotic components of the ecosystem. However, the primary form of nitrogen on Earth is nitrogen gas, which cannot be used by most animals and plants. Thus, nitrogen gas must first be converted into a usable form by nitrogen-fixing bacteria before it can be cycled through other living organisms. The use of nitrogen-containing fertilizers and animal waste products in human agriculture has greatly influenced the...

The Carbon Cycle

The Carbon Cycle

Carbon is the basis of all organic matter on Earth, and is recycled through the ecosystem in two primary processes: one in which carbon is exchanged among living organisms, and one in which carbon is cycled over long periods of time through fossilized organic remains, weathering of rocks, and volcanic activity. Human activities, including increased agricultural practices and the burning of fossil fuels, has greatly affected the balance of the natural carbon cycle.

The Sulfur Cycle

The Sulfur Cycle

Sulfur, an important element in the chemical makeup of proteins, is recycled through the atmosphere and aquatic and terrestrial environments. Found in the atmosphere as sulfur dioxide (SO2), sulfur is released by decaying organisms, weathered rocks, geothermal vents, volcanos, and burning fossil fuels. It is deposited into the ecosystem, cycled through the biotic community, and either released back into the atmosphere as gas or deposited in marine sediment for long-term storage and eventual...

You might also read

Related Articles

Articles linked to this work by shared authors, journal, and citation graph.

Sort by

Same author

Consciousness indicators, mimicry, and internal variants.

Trends in cognitive sciences·2026

Same author

Modality-agnostic decoding of vision and language from fMRI.

eLife·2026

Same author

Identifying indicators of consciousness in AI systems.

Trends in cognitive sciences·2025

Same author

Evidence for compositionality in fMRI visual representations via Brain Algebra.

Communications biology·2025

Same author

Enhancing deep neural networks through complex-valued representations and Kuramoto synchronization dynamics.

ArXiv·2025

Same author

Through their eyes: Multi-subject brain decoding with simple alignment techniques.

Imaging neuroscience (Cambridge, Mass.)·2025

Same journal

Dynamic coordination and segregation mechanisms in higher cortex for parallel task processing.

Neuron·2026

Same journal

Higher-order thalamic bursts are drivers of attention control.

Neuron·2026

Same journal

Composing trajectories for rapid inference of navigational goals.

Neuron·2026

Same journal

Peri-head distance coding in the mouse brainstem.

Neuron·2026

Same journal

A two-timepoint framework for sensitive and specific single-cell activity screening.

Neuron·2026

Same journal

From first impressions to bonds: The neural dynamics of social relationships.

Neuron·2026

See all related articles

Search research articles

Related Experiment Video

Updated: Feb 6, 2026

Measurement of Neurophysiological Signals of Ignoring and Attending Processes in Attention Control

Measurement of Neurophysiological Signals of Ignoring and Attending Processes in Attention Control

Published on: July 5, 2015

Attention Cycles.

Rufin VanRullen¹

¹CerCo, CNRS, UMR5549, Université de Toulouse, 31052 Toulouse, France.

|August 24, 2018

Summary

This summary is machine-generated.

Attention may not be a constant spotlight but rather a rhythmic process operating at 4-8 Hz. New intracranial recordings in monkeys and humans validate this oscillatory attention theory and its neural underpinnings.

More Related Videos

Touchscreen Sustained Attention Task SAT for Rats

Touchscreen Sustained Attention Task SAT for Rats

Published on: September 15, 2017

Measuring Attentional Biases for Threat in Children and Adults

Measuring Attentional Biases for Threat in Children and Adults

Published on: October 19, 2014

Related Experiment Videos

Last Updated: Feb 6, 2026

Measurement of Neurophysiological Signals of Ignoring and Attending Processes in Attention Control

Measurement of Neurophysiological Signals of Ignoring and Attending Processes in Attention Control

Published on: July 5, 2015

Touchscreen Sustained Attention Task SAT for Rats

Touchscreen Sustained Attention Task SAT for Rats

Published on: September 15, 2017

Measuring Attentional Biases for Threat in Children and Adults

Measuring Attentional Biases for Threat in Children and Adults

Published on: October 19, 2014

Area of Science:

Cognitive Neuroscience
Neurophysiology

Background:

Traditional models view attention as a continuous spotlight.
Emerging evidence suggests attention operates rhythmically at approximately 4-8 Hz.

Purpose of the Study:

To validate the rhythmic operation of attention.
To characterize the oscillatory neural bases of attention.

Main Methods:

Intracranial recordings in non-human primates.
Intracranial recordings in human subjects.

Main Results:

New data support the rhythmic attention model.
Neural oscillations at 4-8 Hz are linked to attentional processes.

Conclusions:

Attention functions rhythmically, challenging the continuous spotlight view.
Oscillatory neural activity provides the basis for rhythmic attention.