Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Seaweed engineers build crustacean homes; old forests store new nitrogen

23.10.2014

Highlights from the October 2014 issue of the Ecological Society of America’s journal Ecology, published online today.

Invasive seaweed shelters native crustacean


A Japanese seaweed gains a holds on a mudflat in Charleston Harbor, S.C., by clinging to tube-building decorator worms (Diopatra cuprea) rooted firmly in the mud. The invasive Gracilaria vermiculophylla seaweed provides shelter for a small native crustacean. Credit, Erik Sorka.


The tall, mature trees of a late-succession forest (right) stand next to the young regrowth of a clear-cut forest in central Pennsylvania. The deeper volume of organic matter on the floor of a mature forest can capture more of the nutrient nitrogen when it enters the forest than the clear-cut can. Credit, David Lewis.

On the tidal mudflats of Georgia and South Carolina, the red Japanese seaweed Gracilaria vermiculophylla is gaining a foothold where no native seaweeds live. Only debris and straggles of dead marsh grass used to break the expanse of mud at low tide. Crabs, shrimp, and small crustaceans mob the seaweed in abundance. What makes it so popular?

Not its food value. On mudflats near Savannah, Ga., Wright and colleagues found that the tiny native crustacean Gammarus mucronatus (one of the 9,500 species of amphipod, which includes sand fleas) does not eat much of the seaweed. Rather, its attraction is structural. The seaweed protects the small crustaceans from predators at high tide and from the dry heat of the flats at low tide. G. mucronatus was up to 100 times as abundant on seaweed invaded mudflats.

The arrival of an aggressive invader disrupts the food webs and physical and chemical characteristics of the environment it enters. Disruption is often bad for native species that get shaded, crowded, or eaten by the invader, and reports of the disastrous consequences of invasive species have grown familiar. But the story for individual species is more complicated, as the presence of the invader is sometimes a benefit, either as a new source of food or, as in this case, of shelter.

Engineering or food? Mechanisms of facilitation by a habitat-forming invasive seaweed (2014) JT Wright, JE Byers, JL DeVore, and E Sotka. Ecology 95(10): 2699-2706. http://dx.doi.org/10.1890/14-0127.1 [open access]

  • Jeffrey T. Wright, Australian Maritime College, National Centre for Marine Conservation and Resource Sustainability
  • James E. Byers, University of Georgia, Odum School of Ecology
  • Jayna Lynn DeVore, University of Sydney, School of Biological Sciences
  • Erik Sotka , College of Charleston, Department of Biology

Mature forests store nitrogen in soil

Ecologists working in central Pennsylvania forests have found that forest top soils capture and stabilize the powerful fertilizer nitrogen quickly, within days, but release it slowly, over years to decades. The discrepancy in rates means that nitrogen can build up in soils. Forests may be providing an unappreciated service by storing excess nitrogen emitted by modern agriculture, industry, and transport before it can cause problems for our waterways.

Nitrogen is an essential nutrient, required for all living things to live and grow. Though a major component of the air, it is largely inaccessible, captured only through the metabolism of certain microbes or washed to earth in the form of ammonia, nitrogen oxides, or organic material by rain, snow, and fog. On land, microbes, fungi, and plants incorporate what doesn’t wash away into proteins, DNA, and other biological components. Organic matter in the soil – the remains of fallen leaves, animal droppings, and dead things in various states of decay – can also capture newly deposited nitrogen, holding it stable in the soil.

Mature forests store nitrogen more efficiently than young forests recovering from clear-cuts the authors found, because they have been accumulating organic matter on the forest floor for a century or more. When a forest is clear cut, erosion soon follows, washing away top soil. A young stand of trees a decade old is beginning to rebuild the organic layer, but it will take many autumns to accumulate.

The orderly succession of changes in resident species as a forest grows and ages is a classic preoccupation of ecological theory. The exchange of nutrients among the species and the non-living landscape also changes with succession, and the discovery that nitrogen accumulates in the organic soil indicates something important about how an ecosystem’s nutrient economy ages.  It was thought, up through the 1970s and early 80s, that an ecosystem grows like a person. At some point, forests, like people, stop getting bigger and adding new biomass. Ecologists argued that the ability to capture incoming nutrients stopped with the end of growth. But by the mid-80s, it was clear that mature ecosystems did continue to absorb nitrogen, mostly in soil. By showing that nitrogen capture is much faster than its release, Lewis and colleagues suggest a mechanism by which old ecosystems can accumulate new inputs of nutrients.

Because soils rich in organics can quickly incorporate nitrogen, forest soils have the potential to absorb excess nitrogen that has been newly added to the biosphere through human activities. Application of synthetic nitrogen fertilizers and combustion of fossil fuels produce substantial amounts of ammonia and nitrogen oxides. Since industrialization, human activities have tripled the global rate of fixation of nitrogen from the air. The excess has perturbed the nutrient economies of many ecosystems, most visibly by feeding algal blooms and oxygen-deprived dead zones in lakes and estuaries. The study suggests that we may want to strategically conserve or restore forests, preserving organic-rich soils where they intercept the movement of ground water towards streams, lakes, or estuaries.

Forest succession, soil carbon accumulation, and rapid nitrogen storage in poorly-remineralized soil organic matter (2014) DB Lewis, M Castellano, and JP Kaye. Ecology 95(10): 2687-93. http://dx.doi.org/10.1890/13-2196.1 [open access]

  • David Bruce Lewis, University of South Florida, Tampa. Corresponding author.
  • Michael J. Castellano, Iowa State University, Ames
  • Jason P. Kaye, The Pennsylvania State University, University Park

Unexpected diets

In streams around the world, small animals feeding at the bottom of the food chain are not eating the selection of decaying leaves, slimy film streambed films, and fine particulate detritus that ecologist have presumed they eat.

You are not always what we think you eat: selective assimilation across multiple whole-stream isotopic tracer studies. (2014) W. K. Dodds, S. M. Collins, S. K. Hamilton, J. L. Tank, S. Johnson, J. R. Webster, K. S. Simon, M. R. Whiles, H. M. Rantala, W. H. McDowell, S. D. Peterson, T. Riis, C. L. Crenshaw, S. A. Thomas, P. B. Kristensen, B. M. Cheever, A. S. Flecker, N. A. Griffiths, T. Crowl, E. J. Rosi-Marshall, R. El-Sabaawi, and E. Martí. Ecology 95(10):2757–2767. http://dx.doi.org/10.1890/13-2276.1

###

ESA is the world’s largest community of professional ecologists and a trusted source of ecological knowledge, committed to advancing the understanding of life on Earth.  The 10,000 member Society publishes six journals and broadly shares ecological information through policy and media outreach and education initiatives. The Society’s Annual Meeting attracts over 3,000 attendees and features the most recent advances in ecological science. Visit the ESA website at http://www.esa.org.

Liza Lester | Eurek Alert!
Further information:
http://www.esa.org/esa/seaweed-engineers-build-crustacean-homes-old-forests-store-new-nitrogen/

More articles from Ecology, The Environment and Conservation:

nachricht Bioinvasion on the rise
15.02.2017 | Universität Konstanz

nachricht Litter Levels in the Depths of the Arctic are On the Rise
10.02.2017 | Alfred-Wegener-Institut, Helmholtz-Zentrum für Polar- und Meeresforschung

All articles from Ecology, The Environment and Conservation >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Breakthrough with a chain of gold atoms

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

Im Focus: DNA repair: a new letter in the cell alphabet

Results reveal how discoveries may be hidden in scientific “blind spots”

Cells need to repair damaged DNA in our genes to prevent the development of cancer and other diseases. Our cells therefore activate and send “repair-proteins”...

Im Focus: Dresdner scientists print tomorrow’s world

The Fraunhofer IWS Dresden and Technische Universität Dresden inaugurated their jointly operated Center for Additive Manufacturing Dresden (AMCD) with a festive ceremony on February 7, 2017. Scientists from various disciplines perform research on materials, additive manufacturing processes and innovative technologies, which build up components in a layer by layer process. This technology opens up new horizons for component design and combinations of functions. For example during fabrication, electrical conductors and sensors are already able to be additively manufactured into components. They provide information about stress conditions of a product during operation.

The 3D-printing technology, or additive manufacturing as it is often called, has long made the step out of scientific research laboratories into industrial...

Im Focus: Mimicking nature's cellular architectures via 3-D printing

Research offers new level of control over the structure of 3-D printed materials

Nature does amazing things with limited design materials. Grass, for example, can support its own weight, resist strong wind loads, and recover after being...

Im Focus: Three Magnetic States for Each Hole

Nanometer-scale magnetic perforated grids could create new possibilities for computing. Together with international colleagues, scientists from the Helmholtz Zentrum Dresden-Rossendorf (HZDR) have shown how a cobalt grid can be reliably programmed at room temperature. In addition they discovered that for every hole ("antidot") three magnetic states can be configured. The results have been published in the journal "Scientific Reports".

Physicist Dr. Rantej Bali from the HZDR, together with scientists from Singapore and Australia, designed a special grid structure in a thin layer of cobalt in...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Booth and panel discussion – The Lindau Nobel Laureate Meetings at the AAAS 2017 Annual Meeting

13.02.2017 | Event News

Complex Loading versus Hidden Reserves

10.02.2017 | Event News

International Conference on Crystal Growth in Freiburg

09.02.2017 | Event News

 
Latest News

From rocks in Colorado, evidence of a 'chaotic solar system'

23.02.2017 | Physics and Astronomy

'Quartz' crystals at the Earth's core power its magnetic field

23.02.2017 | Earth Sciences

Antimicrobial substances identified in Komodo dragon blood

23.02.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>