ecodiversity

Coral Reefs: Nature’s Underwater Pharmacies

What’s the Latest Development?
Biologists have begun to discover just what a treasure trove the oceans’ coral reefs are in terms of finding potential cures to some of humanity’s worst diseases. Tens of thousands of chemicals have already been identified and, of those thousands, hundreds are currently under medical investigation. “Sponges are particularly rich sources of chemicals,” said professor Callum Roberts, a marine conservation biologist at the University of York, “particularly anti-cancer chemicals. Many have been shown to be tumor suppresents and one has already been licensed for use in the treatment of leukemia.”

What’s the Big Idea?
Coral reefs naturally represent nature’s largest pharmacy thanks to evolutionary processes which have endowed a wide variety of species with vastly different and highly complex chemical makeups in their intense competition for a limited amount of underwater real-estate. Currently, however, coral reefs are under pressure from a variety of man-made hazards including pollution, over-fishing and climate change. “To lose those possible treatments through the destruction of coral reefs would be an unparalleled act of folly,” said Roberts.

Watch: Coral Reefs | Underwater Pharmacies via BBC

Charged bees can sense electric flower fields

Positively charged bees are able to recognise electric signals given off by flowers as part of the plant pollination strategy.

The electrical signalling works in tandem with other signs such as colour, pattern and fragrance to tell bumblebees (and other insect pollinators) about the amount of nectar and pollen they may contain.

“This novel communication channel reveals how flowers can potentially inform their pollinators about the honest status of their precious nectar and pollen reserves” said co-author Heather Whitney of the University of Bristol.

Generally the flowers are negatively charged and generate a weak electric field while the bees become positively charged as they fly around – the study suggests the charge can build to around 200 volts. The sensation felt by a positive bee meeting a negative plant can be enough to convey snippets of information while its absence could reveal whether the flower has recently hosted another insect.

The biologists noted that not only could the bumblebees tell the difference between various floral electric fields, but when learning to tell two colours apart having an electric field involved sped up the process.

“The co-evolution between flowers and bees has a long and beneficial history, so perhaps it’s not entirely surprising that we are still discovering today how remarkably sophisticated their communication is,” said Daniel Robert, who also worked on the study. He also stressed how a bee’s intelligence made it necessary for the flowers to develop an effective communication strategy: “bees are good learners and would soon lose interest in such unrewarding flowers”.

The exact mechanics by which the bees detect these electrical variations is not fully understood, although the explanation favoured by the researchers is that coming near the charged flowers causes the bees’ fur to “bristle”, like when you hold the back of your hand a couple of millimetres from an old TV screen.

Image: Laurent Jégou / CC BY ND 2.0

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She’s Alive

This is a non-commercial attempt to highlight the fact that world leaders, irresponsible corporates and mindless ‘consumers’ are combining to destroy life on earth. It is dedicated to all who died fighting for the planet and those whose lives are on the line today. The cut was put together by Vivek Chauhan, a young film maker, together with naturalists working with the Sanctuary Asia network (http://www.sanctuaryasia.com/).

Content credit: The principal source for the footage was Yann Arthus-Bertrand’s incredible film HOME http://www.homethemovie.org/. The music was by Armand Amar.

via True Activist

The Microbial Communities of the Future

image: Rainforests of the future may look very different, if global warming alters microbial communities substantially. Photo: dimitridf / Flickr

The world, it turns out, is getting warmer. The extent and precise contours of climate change may never be forecastable, but many scientists are working to test the repercussions of a warmer atmosphere, in order to both inform policy discussions and instigate difficult discussions about adaptation strategies.

Nicholas Bouskill, an ecologist at the University of California at Berkeley, is one such scientist. Through a carefully designed study of jungle floor patches in Puerto Rico, Bouskill and his team are hoping to determine how the microbial make-up of soil changes in response to repeated periods of dryness. “These locations are likely to experience changes in the magnitude of rainfall, with increased drought and longer dry periods,” he writes in a recent edition of the ISME Journal.

It wasn’t necessarily clear how a drier environment would impact the microbial community since soil moisture is a double edged sword: Too much of it, and the diffusion of important gases in and out of the soil is limited; too little, and nutrients might not reach the microbes in sufficient quantities. So how, and how quickly, might soil-based microbial communities change in response to less water? Bouskill sought answers by tracking diversity shifts in plots of soil cut off from rain throughfall for the first time and those experiencing a second artificial drought.

Here’s how the experiment went down. In June of 2008, the scientists set up corrugated plastic canopies over five patches of soil for three months. The next year, they returned, erecting canopies over the same five squares as well as five new ones. Unaltered areas were also included in the study as an experimental control.

With these three experimental conditions, the team would be able to tell not only how less direct water would affect the microbial community, but also how “priming” the soil with drought a year earlier affected things.

The soil’s water chemistry changed significantly, as rainfall exclusion led to higher sodium concentrations, while iron, aluminum, and phosphorous levels were lower. Shifts in the soils’ microbial community compositions, however, were more difficult to predict. Remarkably, Bouskill and his team found that the lower rainfall levels had no discernible effect on the overall amount of soil biomass. The covered patches were just as full of microbial life as the uncovered plots, but they were more homogenous, as genetic diversity dove by 40 percent. Soils experiencing a second artificial drought saw diversity levels bounce back to those of the control plots. As Bouskill puts it, the effect of repeated water exclusion “manifested as changes in the relative abundance of organisms, but not as decreased diversity.”

So how might the diversity of soil patches in Puerto Rico affect our predictions for microbial life in a warming world? Beyond the specific prescriptions for tropical rain forests (more Planctomycetes and Actinobacteria), it appears that repeated exposure to a new climate regime bolsters a community’s ability to maintain diversity. The relative abundances of particular species may change drastically, but the overall amount of genetic diversity appears to remain relatively constant.

This is an encouraging result for the planet’s biodiversity, but the jury’s still out on how ecosystems will change in other respects. For example, how will overall metabolic cycling of nutrients like carbon or nitrogen change? And how would such changes affect the rest of the jungle? After all, the soil’s microbial soup is the unseen arbiter of the jungle’s health, and any substantial changes in microbial composition, diversity, or abundance will change the entire system in unpredictable ways. Hopefully, the surprisingly robust microbial diversity will help curtail drastic ecosystem-wide changes.

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Discovery Channel | Curiosity | The Ocean: Our Final Frontier

…on Earth :)