Ecology & Zoology

A new study suggests that the iron-rich winter runoff from Pacific Northwest streams and rivers, combined with the wide continental shelf, form a potent mechanism for fertilizing the nearshore Pacific Ocean, leading to robust phytoplankton production and fisheries.

The study, by three Oregon State University oceanographers, was just published by the American Geophysical Union in its journal, Geophysical Research Letters.

West coast scientists have observed that ocean chlorophyll levels, phytoplankton production and fish populations generally increase in the Pacific Ocean the farther north you go (from southern California to northern Washington).

The sugar-containing nectar secreted by plants and consumed by pollinators shares a number of similarities to fitness drinks, including ingredients such as amino acids and vitamins. In addition to these components, nectar can also contain secondary metabolites such as the alkaloid nicotine and other toxic compounds. Scientists Danny Kessler and Ian Baldwin from the Max Planck Institute for Chemical Ecology in Jena, Germany, recently addressed the question, why would plants risk poisoning the insects and birds that provide pollination services? Their findings have been published in The Plant Journal.

Kessler and Baldwin examined the nectar of a wild tobacco species, Nicotiana attenuata, and discovered that it is flavoured with 35 secondary compounds.

How does life survive in the black depths of the ocean? At the surface, sunlight allows green plants to "fix" carbon from the air to build their bodies. Around hydrothermal vents deep in the ocean live communities of giant clams with no gut and no functional digestive system, depending on symbiotic bacteria to use energy locked up in hydrogen sulfide to replace sunlight.

North American marine turtles are at risk if global warming occurs at predicted levels, according to scientists from the University of Exeter. An increase in temperatures of just one degree Celsius could completely eliminate the birth of male turtles from some beaches. A rise of three degrees Celsius would lead to extreme levels of infant mortality and declines in nesting beaches across the USA.


Marine turtle. Credit: Copyright Lucy Hawkes, MTRG

At least to female swordfish.

Scientists from the Universities of Exeter and Glasgow today reveal how some females become sexually mature more quickly if they see attractive males.

The researchers studied a captive population of green swordtail fish, a species native to Central America and popular in tropical aquariums. The green swordtail is named after the striking sword-like growth, which males develop on their tail-fin, so they appear larger and more attractive to females.


Male green swordtail fish. Credit: Copyright Craig Walling, University of Exeter

At a 9 am press conference at the American Association for the Advancement of Science Annual Meeting (AAAS) on February 18th, an international team of leading fisheries economists, biologists, and ecologists will call for the abolition of government fuel subsidies that keep deep-sea fishing vessels moving to deeper waters.

"Industrial fisheries are now going thousands of miles, thousands of feet deep and catching things that live hundreds of years in the process - in the least protected place on Earth," says Elliott Norse of the Marine Conservation Biology Institute.

In international waters beyond the 200 nautical mile Exclusive Economic Zones (EEZs) of coastal countries, many of the fisheries are virtually unregulated.

Industrial agriculture faces painful challenges: the end of cheap energy, depleted water resources, impaired ecosystem services, and unstable climates. Scientists searching for alternatives to the highly specialized, energy intensive industrial system might profitably look to the biological synergies inherent in multi-species systems, according to an article in the March-April 2007 issue of Agronomy Journal. The paper's author, Fred Kirschenmann, Distinguished Fellow for Leopold Center for Sustainable Agriculture, Iowa State University, states that industrial agriculture assumes:

 

Plants have an immune system that resists infection, yet 10% of the world's agricultural production is lost annually to diseases caused by bacteria, fungi, and viruses. Understanding how disease resistance works may help combat this scourge.

In a new study published online this week in the open-access journal PLoS Biology, Tessa Burch-Smith, Savithramma Dinesh-Kumar, and colleagues show how one aspect of the plant immune system is defined by the gene-for-gene hypothesis: a plant Resistance (R) gene encodes a protein that specifically recognizes and protects against one pathogen or strain of a pathogen carrying a corresponding Avirulence (Avr) gene.

In tobacco and its relatives, the N resistance protein confers resistance to infection by the Tobacco mosaic virus (TMV).

The simultaneous effect of habitat fragmentation, overexploitation, and climate warming could accelerate the decline of populations and substantially increase their risk of extinction, a study published in the Proceedings of the Royal Society B has warned.


The viability of many marine and terrestrial species could be impaired due to interacting human activities that cause the loss of species' habitats, overexploitation of their populations and warming of their environments. Credit: Top left: John Veron from Corals of the World. Top right: Wolcott Henry/Marine Photobank, Bottom left: Steve Spring/Marine Photobank, Bottom right: NASA-GSFC/Marine Photobank

Sometimes it is better to follow the advice of others rather than your own mind even though you seem to have things under control. Not only humans but also fish follow this doctrine as shown by ecologists Jörgen Johnsson and Fredrik Sundström of Göteborg University, Sweden, in the journal Ethology.

They allowed European minnows to learn the correct route through a maze to obtain food in the presence or absence of a predatory brown trout. Then a naïve minnow joined the group on later trials either in the presence or absence of the trout.