Showing posts with label Ecosystem. Show all posts
Showing posts with label Ecosystem. Show all posts

Wednesday, April 02, 2014

Great Pacific Garbage Patch; Plastic Trash Altering Ocean Habitats


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Great Pacific Garbage Patch; Plastic Trash Altering Ocean Habitats

Plastic Trash Altering Ocean Habitats, Scripps Study Shows

By Mario Aguilera
ucsdnews.ucsd.edu
5-8-2012

     A 100-fold upsurge in human-produced plastic garbage in the ocean is altering habitats in the marine environment, according to a new study led by a graduate student researcher at Scripps Institution of Oceanography at UC San Diego.

In 2009 an ambitious group of graduate students led the Scripps Environmental Accumulation of Plastic Expedition (SEAPLEX) to the North Pacific Ocean Subtropical Gyre aboard the Scripps research vessel New Horizon. During the voyage the researchers, who concentrated their studies a thousand miles west of California, documented an alarming amount of human-generated trash, mostly broken down bits of plastic the size of a fingernail floating across thousands of miles of open ocean.

At the time the researchers didn’t have a clear idea of how such trash might be impacting the ocean environment, but a new study published in the May 9 online issue of the journal Biology Letters reveals that plastic debris in the area popularly known as the “Great Pacific Garbage Patch” has increased by 100 times over in the past 40 years, leading to changes in the natural habitat of animals such as the marine insect Halobates sericeus. These “sea skaters” or “water striders”—relatives of pond water skaters—inhabit water surfaces and lay their eggs on flotsam (floating objects). Naturally existing surfaces for their eggs include, for example: seashells, seabird feathers, tar lumps and pumice. In the new study researchers found that sea skaters have exploited the influx of plastic garbage as new surfaces for their eggs. This has led to a rise in the insect’s egg densities in the North Pacific Subtropical Gyre.

Such an increase, documented for the first time in a marine invertebrate (animal without a backbone) in the open ocean, may have consequences for animals across the marine food web, such as crabs that prey on sea skaters and their eggs.

“This paper shows a dramatic increase in plastic over a relatively short time period and the effect it’s having on a common North Pacific Gyre invertebrate,” said Scripps graduate student Miriam Goldstein, lead author of the study and chief scientist of SEAPLEX, a UC Ship Funds-supported voyage. “We’re seeing changes in this marine insect that can be directly attributed to the plastic.”

The new study follows a report published last year by Scripps researchers in the journal Marine Ecology Progress Series showing that nine percent of the fish collected during SEAPLEX contained plastic waste in their stomachs. That study estimated that fish in the intermediate ocean depths of the North Pacific Ocean ingest plastic at a rate of roughly 12,000 to 24,000 tons per year.

Monday, September 09, 2013

CLIMATE CHANGE: New Research Reveals Alarming Impact on Oceans' Ecosystems


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Plankton

Climate change will upset vital ocean chemical cycles

By University of East Anglia
9-8-13

      New research from the University of East Anglia shows that rising ocean temperatures will upset natural cycles of carbon dioxide, nitrogen and phosphorous.

Plankton plays an important role in the ocean’s carbon cycle by removing half of all CO2 from the atmosphere during photosynthesis and storing it deep under the sea – isolated from the atmosphere for centuries.

Findings published today in the journal Nature Climate Change reveal that water temperature has a direct impact on maintaining the delicate plankton ecosystem of our oceans.

The new research means that ocean warming will impact plankton, and in turn drive a vicious cycle of climate change.

Researchers from UEA’s School of Environmental Sciences and the School of Computing Sciences investigated phytoplankton – microscopic plant-like organisms that rely on photosynthesis to reproduce and grow.

Lead researcher Dr Thomas Mock, said: “Phytoplankton, including micro-algae, are responsible for half of the carbon dioxide that is naturally removed from the atmosphere. As well as being vital to climate control, it also creates enough oxygen for every other breath we take, and forms the base of the food chain for fisheries so it is incredibly important for food security.

“Previous studies have shown that phytoplankton communities respond to global warming by changes in diversity and productivity. But with our study we show that warmer temperatures directly impact the chemical cycles in plankton, which has not been shown before.”

Collaborators from the University of Exeter, who are co-authors of this study, developed computer generated models to create a global ecosystem model that took into account world ocean temperatures, 1.5 million plankton DNA sequences taken from samples, and biochemical data.

“We found that temperature plays a critical role in driving the cycling of chemicals in marine micro-algae. It affects these reactions as much as nutrients and light, which was not known before,” said Dr Mock.

“Under warmer temperatures, marine micro-algae do not seem to produce as many ribosomes as under lower temperatures. Ribosomes join up the building blocks of proteins in cells. They are rich in phosphorous and if they are being reduced, this will produce higher ratios of nitrogen compared to phosphorous, increasing the demand for nitrogen in the oceans.

“This will eventually lead to a greater prevalence of blue-green algae called cyanobacteria which fix atmospheric nitrogen,” he added.

The research was funded by the Natural Environment Research Council (NERC), 454 Life Sciences (Roche), the Leverhulme Trust, the European Union (FP7), the German Research Foundation (DFG) and the Earth and Life Systems Alliance (ELSA).

‘The impact of temperature on marine phytoplankton resource allocation and metabolism’ by A Toseland, SJ Daines, JR Clark, A Kirkham, J Strauss, C Uhlig, TM Lenton, K Valentin, GA Pearson, V Moulton and T Mock is published in Nature Climate Change.