Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

VIMS reports intense and widespread algal blooms

02.09.2015

Researchers explore new tools to monitor scope and impacts

Water sampling and aerial photography by researchers at William & Mary's Virginia Institute of Marine Science show that the algal blooms currently coloring lower Chesapeake Bay are among the most intense and widespread of recent years.


An exceptionally dense bloom of Alexandrium monilatum was observed in lower Chesapeake Bay along the north shore of the York River between Sarah's Creek and the Perrin River on 8/17/2015.

Credit: © W. Vogelbein/VIMS.

VIMS professor Kimberly Reece reports that water samples collected near the mouth of the York River on August 17 contained up to 200,000 algal cells per milliliter, the densest concentration she has seen in nearly 10 years of field sampling. A sample with a concentration of even 1,000 algal cells per milliliter is visible to the naked eye and considered dense enough to be called a bloom.

The current blooms are dominated by a single-celled protozoan called Alexandrium monilatum, an algal species known to release toxins harmful to other marine life, particularly larval shellfish and finfish. Since mid-August, VIMS has received sporadic and localized reports of small numbers of dead fish, oysters, and crabs from the lower York River and adjacent Bay waters associated with nearby blooms, although a direct cause/effect relationship has not been established for any of these events.

Aerial photography and water sampling by VIMS professor Wolfgang Vogelbein between August 17th and 27th confirmed the blooms' intensity in the lower York River, and revealed that they extended much farther up the York River and out into Chesapeake Bay than previously reported. The flyovers were facilitated by the Virginia Marine Resources Commission.

"This is new and important information," says Vogelbein, "as we have never appreciated that Alexandrium extends so far into the mainstem of the Bay or so far up the York River." Bloom patches in the mainstem reach from the York River to the mouth of the Rappahannock River, across the Bay to within 3-4 miles of Cape Charles, and as far south as the Chesapeake Bay Bridge-Tunnel. The bloom patches are most dense on the western side of the Bay, with other areas experiencing less activity. "The main body of the bloom is several miles off shore," says Vogelbein, "and thus wasn't appreciated prior to the recent flyovers."

Alexandrium monilatum is one of several species of harmful algae that are of emerging concern in Chesapeake Bay. It was first conclusively detected in Bay waters in 2007, when Reece and colleagues used microscopy and DNA sequences to identify it as the dominant species of a bloom that persisted for several weeks in the York River. There are generic reports of Alexandrium in the Bay from the mid-1940s, and specific reports of A. monilatum in the mid-1960s, but none in the intervening decades.

The recent sampling and aerial photography show that the epicenter of the A. monilatum bloom is near the mouth of the York River. Smaller, less dense patches are visible within Mobjack Bay and its tributaries, the Back and Poquoson rivers, and near the mouth of the James and Elizabeth rivers.

Reports of algal blooms in the lower York River started around July 22nd. As in recent years, the initial summer blooms began with concentrations of the alga Cochlodinium polykrikoides, before shifting after 2-3 weeks into blooms dominated by A. monilatum. As of the last week of August, the A. monilatum bloom in the York River persists but has grown markedly less dense.

New tools to better understand blooms and toxins

Monitoring the scope and impacts of an algal bloom is notoriously difficult, particularly in areas like Chesapeake Bay where tides, winds, currents, and a convoluted shoreline combine to create blooms that are both patchy and ephemeral.

A further complication is that the blooms typically contain a changing mix of algal species, some of which may or may not--depending on environmental conditions--produce the toxins that transform an innocuous algal aggregation into a harmful algal bloom or HAB.

"We see high variation among our samples," says Reece, "even between those that were collected from sites a few hundred yards apart or taken from the same site a few hours apart."

To better characterize local blooms and their potential impacts, Reece and Vogelbein have recently joined with colleagues at VIMS and other institutions to bring new tools and techniques to their efforts.

One of these collaborations involves the use of Dataflow, a high-tech instrument used to monitor water quality over large areas. Deployed from a small boat operating at speeds up to 25 knots, Dataflow passes surface water collected through a keel-mounted pipe past an array of water-quality sensors that record dissolved oxygen, salinity, temperature, turbidity, chlorophyll, and pH--all parameters that relate to algal abundance.

In mid-August, VIMS professor Iris Anderson teamed with colleagues Jen Stanhope, Hunter Walker, and Gail Scott to run Dataflow through several bloom patches in the lower York River. This was supplemented by a simultaneous Dataflow run in the lower James River by colleagues at Old Dominion University and the Hampton Roads Sanitation District. Both teams are now comparing their sensor data with water samples taken enroute to further explore potential links between water quality and bloom characteristics.

The Dataflow runs got a serendipitous boost from an ongoing study of algal productivity by VIMS professor Mark Brush and post-doctoral researcher Sam Lake. Their monthly sampling of photosynthesis and respiration in the York River happened to take place on the same day and will help put the Dataflow measurements in a seasonal context.

On yet another front, VIMS professor Jian Shen will feed data from the Dataflow runs into his three-dimensional computer model of water flow in Chesapeake Bay. The model holds promise for predicting bloom dynamics, potentially giving shellfish growers and other concerned parties advance warning of any impacts.

The Dataflow cruises in the York and James rivers were also accompanied by over-flights from a NASA Langley airplane that was equipped with electromagnetic sensors and cameras, and by the collection of data from NASA satellites. Researchers are now "ground-truthing" the aerial and satellite imagery by comparing it with direct measurements of algae and water quality from samples collected at the same time and in the imaged locations.

Reece sees great promise in collaborating with scientists at NASA and NOAA to advance model development and the use of remote sensing for predicting algal bloom patterns in Chesapeake Bay.

Lab work and bioassays

Once water samples from a bloom are returned to VIMS, researchers in a number of labs begin the laborious process of identifying the species present and characterizing any toxins.

Members of the Reece lab--Bill Jones, Gail Scott, and Alanna MacIntyre--use both microscopic analyses and DNA tests to identify potentially harmful algal species. Development of these molecular DNA assays is a primary focus of Reece's research at VIMS. The lab group plans to extract and analyze DNA from about 300 of the 500 water samples collected so far this summer.

VIMS professor Juliette Smith--working with adjunct professor Tom Harris--has focused her efforts on characterizing the complex array of toxins that algae can generate. "A single cell can produce multiple toxins," says Smith. "In addition, the same toxin can be produced by multiple species. For instance, saxitoxins, which cause paralytic shellfish poisoning, can be produced by both dinoflagellates and cyanobacteria."

Smith and other researchers at VIMS are also testing to what degree bloom-derived toxins might be moving up the food web to impact marine life and potentially human health. Graduate student Sarah Pease is using funds from Virginia Sea Grant to monitor the health of caged oysters in waters near the Goodwin Islands, and is also working with Smith to conduct toxin analyses on oyster tissues.

Pease and Patrice Mason--members of Vogelbein's lab--are conducting toxicity "bioassays" with algae from both laboratory cultures and field samples. These tests involve bathing small numbers of oysters and finfish--both larvae and adults--in waters with increasing concentrations of algal cells and, more recently, isolated and purified toxins. They are a standard method for gauging the effects of HABs on living organisms. This year's bioassays are still in progress.

Media Contact

David Malmquist
davem@vims.edu
804-684-7011

 @VIMS_News

http://www.vims.edu 

David Malmquist | EurekAlert!

Further reports about: Chesapeake Bay DNA Marine VIMS algal bloom algal blooms mouth oysters toxins water quality

More articles from Life Sciences:

nachricht New risk factors for anxiety disorders
24.02.2017 | Julius-Maximilians-Universität Würzburg

nachricht Stingless bees have their nests protected by soldiers
24.02.2017 | Johannes Gutenberg-Universität Mainz

All articles from Life Sciences >>>

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

Stingless bees have their nests protected by soldiers

24.02.2017 | Life Sciences

New risk factors for anxiety disorders

24.02.2017 | Life Sciences

MWC 2017: 5G Capital Berlin

24.02.2017 | Trade Fair News

VideoLinks
B2B-VideoLinks
More VideoLinks >>>