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This page includes news articles of international and national interest. Seagrass-Watch HQ does not guarantee, and accepts no legal liability whatsoever arising from or connected to, the accuracy, reliability, currency or completeness of any news material contained on this page or on any linked site. The material on this page may include the views or recommendations of third parties, which do not necessarily reflect the views of the program nor it's supporters, or indicate commitment to a particular course of action

 

 

 

 

 

Tampa Bay's seagrass beds to take big hit from rain-fueled algae blooms

19 August 2015, TBO.com (USA)

Seagrass beds, which flourish in less than 6 feet of clear water, are among the bay’s most vital habitats. Photo Credit: Tampa Bay Watch

Besides the standing water in yards and homes and the cars left half submerged in the streets, the constant rains over the past month are poised to claim another victim: Tampa Bay.

The rain runoff, much of which carries substantial amounts of nitrogen and other nutrients, wound up in the bay. The huge influx of nutrients is expected to result in algae blooms that will cloud the water, block the sun from reaching the bottom and likely kill off vast beds of seagrass, considered one of the key building blocks of a healthy estuarine system, environmental officials said.

“We are funneling an awful lot of storm water runoff into the bay,” said Tampa Bay Estuary Program spokeswoman Nanette Holland O’Hara. “There are lots of things in the runoff, mainly nitrogen loadings, which spark the growth of algae, turns the water green and consumes oxygen.

“I would not be surprised to see localized fish kills as well,” she said, “particularly in areas of the bay that have limited circulation, like upper Tampa Bay.”

A fish kill was reported along Bayshore Boulevard in Hillsborough Bay last week. State scientists were called in to test the water, but the results of those tests were unavailable Wednesday.

Seagrass beds, which flourish in less than 6 feet of clear water, are among the bay’s most vital habitats. The beds are important nurseries and feeding grounds for numerous species in Tampa Bay, including shrimp, spotted sea trout, red drum and snook.

The runoff’s impact down the road is unclear.

“We’ve had unrelenting runoff going into the bay,” O’Hara said. “In my lifetime, and everyone I’ve talked to says the same thing, I haven’t seen an event like this, with this kind of torrential rain day after day after day for weeks.”

In the winter of 1997-98, parts of Tampa received about 10 inches of rain in two days, resulting in an algae bloom that led to the loss of about 1,200 acres of seagrass in the bay, she said.

This year is much worse. Some local areas saw more than 20 inches of rain fall within a two-week period at the end of July and beginning of August.

The rain over the past month has presented problems for local governments on both sides of the bay. Runoff was mixed with raw sewage and overcame the capacities of treatment plants. The end result: Much of the runoff and sewage went untreated into the bay, providing a fetid soup that is perfect for algae growth.

“Local government wastewater systems have just been overwhelmed,” O’Hara said. “It’s an aging infrastructure that is just not designed to handle this type of event.”

She said some algae blooms already are occurring in pockets of the Bay where water circulation is at a minimum.

“We would not be surprised to hear about algae blooms particularly in the upper part of the bay,” she said, where algae blooms are frequent, even without driving rains.

Just when algae blooms will take hold is uncertain.

O’Hara said a portion of Old Tampa Bay near Clearwater already has a bloom that is visible from the Bayside Bridge.

“It really depends on how much runoff makes it into the bay,” she said. “We’ve been getting close to an inch of rain every day and blooms could pop up at any time.”

Seagrass beds have made a remarkable comeback since the 1970s and now cover more than 40,000 acres of bay bottom.

“Unfortunately,” said Tom Ash, assistant director of water management with the Hillsborough County Environmental Protection Commission, “seagrass beds will take a step backwards this year. They will take a hit.”

Algae is a microscopic plant and grows with sunlight, he said. So as the clouds cleared and the sun broke through for the better parts of the days this week, algae blooms are the natural result.

The seagrass damage from algae blooms is disheartening, but not permanent, O’Hara said.

“The bay has been fairly resilient to these types of unprecedented, extreme events,” O’Hara said. “We will see a rebound.”

More information: Click Here


Australia Aims to Shield Mining Projects From Green Groups

18 August 2015, Wall Street Journal (Australia)

Australia’s conservative government plans to amend environmental laws to prevent green groups from challenging mining projects in which they have no direct involvement.

Opening another front in a long-running battle with the environmental movement, Industry Minister Ian Macfarlane told Parliament on Tuesday that “there is a strategy to destroy jobs” and that activists were blocking resource projects “regardless of the economic impact on the community.”

The push to amend environmental laws comes after a court earlier this month overturned approval for Indian conglomerate Adani Group to build one of the world’s biggest new coal mines on scrubland near the Great Barrier Reef.

Environmental groups went to court to try to stop the Carmichael coal mine project amid concerns the mine and associated infrastructure in the Galilee Basin of tropical Queensland state could endanger a rare lizard known as the yakka skink and another vulnerable species, the ornamental snake.

After that decision, the government said it would to repeal parts of the Environmental Protection and Biodiversity Act that had allowed environmental groups to delay resource projects or even stop them completely.

Prime Minister Tony Abbott, who has been a skeptic on climate change and a champion of Australia’s powerhouse coal industry, said after the decision that green groups were threatening growth and Australia’s national interests. Mr. Abbott promised after winning power in 2013 to make the country more “open for business.”

However, public concern over environmental issues has been rising during Mr. Abbott’s time in office. An Essential Media opinion survey published on Tuesday showed 53% of Australians believed the government wasn’t doing enough to address worries about climate change.

The opposition Labor party has sought to capitalize on mounting environmental worries, promising to make Australia 50% reliant on renewable energy by 2030 if it wins elections next year.

Environmental group Greenpeace said the government aims to strip Australians’ rights to defend nature in response to pressure from the coal industry.

“They’re seeking to legislate special treatment and fast tracking for an industry in decline that causes significant environmental and economic damage,” said David Ritter, chief executive of Greenpeace Australia Pacific. “Australia’s environment laws aren’t very restrictive; they allow you to mine coal in prime farm land and are even failing to protect world heritage areas like the Great Barrier Reef.”

Adani expects the controversial mine to produce as much as 60 million tons of thermal coal annually for export to its power plants in India. Previous estimates pegged the construction costs at 16.5 billion Australian dollars (US$12.2 billion).

More information: Click Here


 

Day visitor' moorings will help protect unique seagrass

16 August 2015, Milford Mercury (Wales)

 

New day visitor moorings have been installed to protect seagrass in the Milford Haven Waterway.

NEW visitor moorings have been placed in the Milford Haven waterway, to help protect a unique and scarce species of seagrass.

Following concerns about the possibility of damage to beds of seagrass in Longoar Bay from vessel anchors, Milford Harbour Users Association (HUA) and the Pembrokeshire Marine Special Area of Conservation Relevant Authorities Group (SACRAG) worked together to come up with a solution.

Marked by red buoys, the two ‘day visitor’ moorings can be used by vessels up to 40 feet long and a maximum weight of 10 tonnes.

They have been positioned in such a way so as to discourage boat users from anchoring to the west of them, where seagrass is present.

Seagrass beds act as nursery areas for commercial fish species, reduce coastal erosion and absorb nutrients and chemicals from coastal run-off.

The Port of Milford Haven, which has insured the markers, said the long term health of the beds was important, as the area is within the Pembrokeshire Marine Special Area of Conservation (SAC) part of a network of important marine sites across Europe.

Made last year, the voluntary agreement also includes protection for subtidal seagrass off Angle and Gelliswick, as well as for the only known bed of maerl in Wales, a chalky red seaweed.

Bill Hurst, harbourmaster at the Port of Milford Haven, said: “I am pleased that the first freely available visitor moorings have been agreed and placed in Longoar Bay.

"The Port of Milford Haven was the final link in the chain to secure their placement and their future.

"Users of the moorings should take careful note of the maximum size boat suitable and safe to make fast to the mooring.”

The visitor moorings have been installed following collaboration with the Pen Ll?n a’r Sarnau SAC and funding from the Welsh Government’s Nature Fund. Assistance has also been provided by Natural Resource Wales’ Skomer Marine Conservation Zone staff.

The approximate positions of the mooring buoys are: 51º42’.723N, 005º06.809W and 51º42’.728N, 005º06.804W.

More information: Click Here

 

Public comments sought on $139 million in proposed oil spill restoration projects

13 August 2015, AL.com (USA)

This aerial photograph taken near Ono Island in Perdido Bay shows a pattern of propeller scars in seagrass beds. Photo Credit: Dauphin Island Sea Lab

The Gulf Coast Ecosystem Restoration Council released a draft Funded Priorities List (FPL) Thursday for public comment. This FPL details active restoration projects total $139.6 million, and recommends setting aside approximately $43.6 million for future projects.

According to a summary posted by the Council, the proposed projects on the list would "provide substantial near-term ecological benefits and would help set the stage for future success with large-scale, comprehensive Gulf restoration."

The FPL included eight projects in Alabama, totaling more than $12.6 million in up front or "Category 1" funding and $13.5 million in "Category 2" funding in the future.

In addition to the Alabama projects, the FPL includes projects to fill in abandoned oil and gas canals and wells, work with land owners to prevent approximately 16,000 pounds of fertilizers per year from entering the Gulf, preserve 9,400 acres of "high value coastal habitat," and invest in Gulf-wide science, coordination and planning programs.

A group of local and national conservation organizations including National Audubon Society, the National Wildlife Federation, Environmental Defense Fund and the Nature Conservancy released a joint statement:

 

"While we haven't yet engaged on the details of the list, we are encouraged to see this first Funded Priorities List moving forward into the public comment period, and we congratulate the RESTORE Council and staff for their efforts to reach this point. The RESTORE Act is focused on comprehensive restoration for the Gulf of Mexico, and our organizations are eager to see strong projects progress to actual construction and implementation.

"With a final BP settlement on the horizon, the RESTORE Council and the Gulf states have a tremendous opportunity ahead to plan for and achieve meaningful restoration and lasting resilience for the essential ecosystems of the Gulf. Our organizations look forward to reviewing and providing comments on this first project list over the coming weeks and working with the Council on the next, more comprehensive FPL process."

Seagrass in Big Lagoon. Photo Credit: Dauphin Island Sea Lab

Bethany Carl Kraft, director of Ocean Conservancy's Gulf Restoration Program said that the FPL marked an important step in the process of choosing which projects to fund through the RESTORE Act.

"While we are still reviewing the details of the draft list, we are encouraged by the approach they seem to be taking, including foundational investments in science and a commitment to funding projects that will begin to address the stressors that prevent our environment from functioning at its full potential," Kraft said in a news release. "The Council appears to have put politics aside, choosing to focus on prioritizing projects by watershed rather than by political boundary, but have unfortunately left out any consideration of the offshore waters of the Gulf of Mexico.

"The success of coastal restoration is intrinsically linked to a healthy marine ecosystem. We encourage the Council to extend their comprehensive approach beyond the salt line."

As established by the RESTORE Act, the Gulf Coast Ecosystem Restoration Council will handle one portion of the Clean Water Act fine money paid by BP and other companies responsible for the 2010 Deepwater Horizon oil spill. In Alabama, it is often referred to as the federal council to differentiate it from the state RESTORE council, which will administer Alabama's portion of the Clean Water Act fine money.

Government officials recently announced a settlement agreement with BP that set the final Clean Water Act fine amount at $5.5 billion, to be paid out in increments over 18 years. If that settlement is finalized as is, the federal council would receive approximately $1.32 billion in total to be put toward comprehensive ecosystem restoration projects, as laid out in the legislation.

Public comments on this draft FPL can be lodged online, or by mailing or emailing the Restoration Council. The deadline for making comments is Sept. 28. There will also be a series of public meetings to discuss the FPL across the Gulf Coast, including one at Mobile's Battle House Renaissance hotel on Sept. 1 at 6 p.m.

More information: Click Here


 

Underwater camera reveals seabed at Weymouth

12 August 2015, ITV News (UK)

The seabed at Weymouth is covered in seagrass, one of the few flowering plants that lives in the sea. Photo Credit: ITV News

People in Dorset have this week been given a unique window on the underwater world which sits just off our coastline. Thanks to an underwater camera they've been able to watch streamed pictures of the seabed at Weymouth

It is less a lawn more a forest of grass. Blades washed in gentle currents, fish darting through the leaves. There is plenty of seagrass, which is actually not a grass or a seaweed, but one of the few flowering plants that lives in the sea.

"It's not really much to look at out of the water, but seagrass is a really important home for many different species. And notably here in Weymouth, sea horses are known to live amongst it."

Conservationists are using a robotic underwater camera to share a unique view of the seabed just of the pier in Weymouth with the public.

On the surface, the team is showing live pictures from the camera. It's a revelation to those passing by who didn't realise it was so close to shore.

"Seagrass, I've never seen in this density before and to see the ROV working it is brilliant, it is really good."

This work is part of a project raising awareness of threats to seagrass beds around our coast. Over the next three years, conservationists are calling on the public to help map and document seagrass beds from Cornwall to Dorset. They say pollution, dredging, some fishing practices and an increase in sediment all threaten the beds. They warn they're getting smaller each year.

Mark Parry from the Community Seagrass Initiative says: "It's found in sheltered bays, in shallow waters. It's a plant so it needs to, it needs light to grow."

"Worldwide, seagrass ranks as the third most popular habitat. You have coral reefs, mangroves and then seagrss. The UK doesn't have mangroves or coral reefs but we do have this incredibly important habitat, seagrass."

There are more chances around the region through the summer to join these quayside sessions. If ever you;ve wondered 'what's down there?', now is your chance to find out.

More information: Click Here


 

Indian River Lagoon sea grass recovery slowly takes root

11 August 2015, The Guardian (USA)

Dolphins cruise past Bob Chamberlain, an environmental scientist with the St. Johns River Water Management District, as he examines sea grass beds in Mosquito Lagoon, part of the 156-mile long Indian River Lagoon system. Scientists suspect a link between a massive sea grass die off between 2011 and 2012 and the unexplained deaths of hundreds of manatees, dolphins, pelicans and other marine life. Photo Credit: News-Journal/JIM TILLER

Lori Morris leaned into the waters of Mosquito Lagoon, trying to see the bottom and feeling with her hands to count sea grass shoots growing there.

Even in a high-tech world of satellites and remote sensing equipment, the best way to determine the health of sea grass beds in the Indian River Lagoon system is to get into the water and look at it, said Morris, an environmental scientist with the St. Johns River Water Management District.

Morris and other district scientists are in Mosquito Lagoon and the rest of the Indian River Lagoon system this summer, visiting specific areas in grass beds — marked by poles and satellite coordinates — they've studied for years. The beds are visited either monthly or twice a year, in winter and summer.

So far this summer, the district and partners say they are finding hopeful signs of recovery from a massive sea grass die off in 2011 and 2012.

Sea grass is crucial to the health of the 156-mile long lagoon system. It's often referred to as the foundation of the abundant marine life in the lagoon, considered one of the more biologically diverse estuaries in the world. Seven grass species grow here, providing food, hiding places and habitat for species from marine worms to prized game fish and even manatees.

A network of grass beds have been monitored in Mosquito Lagoon, the Indian River Lagoon and the Banana River since 1986, as the district and its partners worked to improve conditions and restore the grass beds. By 2007, sea grass appeared to be returning to historic levels of the 1940s, with more than 70,000 acres of grass. But in late 2010 and into 2011, a series of algal blooms occurred across much of the system between Fort Pierce Inlet and New Smyrna Beach.

The thick blanket of algae blocked sunlight from reaching the grass. Eventually 47,000 acres of sea grass disappeared. Scientists also documented the unexplained deaths of hundreds of manatees, dolphins, pelicans and other marine life. Though district scientists and others are still studying the algal blooms and marine life deaths, they suspect the animal deaths were related to the sea grass losses.

Now, many of the grass beds appear to be recovering, Morris said.

The district splits up the monitoring among its partners, with district scientists taking responsibility for some beds, while partners such as the Marine Discovery Center in New Smyrna Beach monitor other beds.

Once they're on a bed, Morris and the other scientists work along a line, stopping every 10 feet to place handmade grids of string and plastic piping on the bottom. They count the grass in previously identified sections of the grid, making note of the number of shoots, the density of grass and water clarity. They count the grass shoots in certain squares of the grids to compare it with results collected in the same spot over time.

Jan Miller, an environmental scientist with the St. Johns River Water Management District, moves a grid as she examines sea grass in Mosquito Lagoon. Following a series of algal blooms in 2010 and 2011, 47,000 acres of sea grass disappeared in the lagoon system. Scientists view sea grass as the foundation of marine life in the lagoon, providing food, hiding places and habitat for species from marine worms to prized game fish and even manatees. Photo Credit: News-Journal/JIM TILLER

They also track how far the bed extends from shore. Grass only grows in areas where light can reach the bottom.

On one morning in late July, the water clarity wasn't great. “Sometimes you just have to crawl along the bottom,” Morris said. Later tests would show the murkiness — somewhat typical in the system in the summertime — was a mix of decaying vegetation, silt and algae.

The water seemed to be a little more turbid than usual, the scientists said, possibly because of recent winds and rain.

Because the water is so shallow, especially in Mosquito Lagoon, even a moderate wind can "kick up the water," said Chuck Jacoby, a supervising environmental scientist with the district. "The waves reach down and bring stuff up from the bottom." Once the fine silt gets mixed into the water, he said, it takes a while for it to settle back out again.

When grass beds are healthy, the grass shoots help hold the silt in place and keep the turbidity down, which in turn helps improve water quality. And when water clarity and quality is good, the grass fares better.

"Getting that whole cycle started seems to be taking some time," said Jacoby.

Overall, district scientists are guardedly optimistic about the grass. A systemwide mapping by aerial photography in 2013 revealed a 12 percent gain in sea grass. And last year district scientists reported moderate increases or at least no sea grass loss in 52 of 69 sites used in the mapping study. The other 17 sites have either continued to lose sea grass or still have no grass at all.

Recovery has been slowest in the areas that had the largest losses between 2011 and 2012: the central part of the Banana River Lagoon and between Cocoa and Wabasso in the Indian River Lagoon, Morris said. "But we are now seeing a lot more natural recruitment," she said, with grass starting to find its way to areas that were bare.

"With just a couple of shoots holding on to the bottom, you can't recreate that ecosystem," said Morris. "It takes a lot longer when you're trying to fill in from zero."

Another systemwide aerial mapping is underway. District officials said it identifies areas that might need further investigation or further protection. It will also help scientists get a better idea of what the improvement trend really is, said Jacoby. So far, it's too soon for them to tell just how long recovery could take.

More information: Click Here


 

Capricorn Coast turtles at higher risk says expert

12 August 2015, Rockhampton Morning Bulletin (Australia)

 

CONCERNING: This female green turtle was found very unwell and in need of urgent help on Fisherman’s Beach at Emu Park earlier this month. Now named Lucy, she’s recovering well at the Quoin Island centre in Gladstone. Five turtles have been rescued from Cap Coast beaches in recent weeks.

AT LEAST some of the money and effort being put into water quality research and monitoring in Gladstone should be transferred north to the Capricorn Coast, according to one of central Queensland's leading sea turtle experts.

Bob McCosker spoke at Emu Park and Yeppoon last week, saying he believed politicians - following media pressure - had focused too much of their attention on Gladstone Harbour rather than on the Capricorn Coast, especially Emu Park and Rosslyn Bay.

Mr McCosker, who operates the purpose-built Quoin Island Turtle Rehabilitation Centre off Gladstone, was in Emu Park for a turtle release and later spoke at a turtle and wildlife rescue information session in Yeppoon.

"There's been a huge amount of publicity about how horrific Gladstone Harbour is, but for three years now, the sickest animals have always come from right here," he told the crowd, who had gathered at Fisherman's Beach for the release of a green turtle called Tula, which had been nursed back to health at Quoin Island.

"This year, 50% of the turtles brought to us have come from where we're standing," he said.

Mr McCosker justified his call for politicians and bureaucrats to rethink their priorities by pointing to figures showing one-third of all turtles cared for at the rehabilitation centre were rescued from the Cap Coast - the largest single group - and those from this area had the poorest survival rate while in care, with less than half recovering.

It is not the first time Mr McCosker has urged authorities to reallocate funds and research efforts.

In October, The Gladstone Observer reported ("Turtles sicker in Yeppoon than in Gladstone") Mr McCosker telling a meeting in that city that, despite appearances, he believed the waters around Rosslyn Bay were in worse condition than Gladstone Harbour.

Gladstone Harbour looked dirty because of the mud, "hence people assume it's unhealthy, which is not the case", he said.

"(In) Rosslyn Bay, you've got this beautiful pristine water that you can see the bottom in 40ft of water and yet half of the animals from up there don't survive.

Quoin Island Turtle Rehabilitation Centre leader Bob McCosker wishes green turtle Tula good luck on her release back into the ocean at Emu Park last week. He says the number of sick turtles on the Cap Coast justifies a greater research effort into local water health.

"At Gladstone Harbour we're saving 60-70%, which to me implies the waters around Rosslyn Bay are in worse condition than the ones they say we're dealing with (in Gladstone)," he said.

"There's tens of millions of dollars being spent on research on Gladstone Harbour and on turtles and marine life, whereas I'd prefer these guys to be looking further up the coast."

Mr McCosker said the rehabilitation centre had cared for about 160 turtles since it opened in March 2012, releasing almost 90 back into the ocean.

Their average time in care was about three months.

About 90% were green turtles, such as Tula, while the remainder were mainly loggerhead or hawksbill turtles.

Mr McCosker conceded his figures may be distorted by the fact Capricorn Coast beaches had more people on them to notice sick turtles.

He said winter was also a difficult time for turtles and the reptiles sometimes floated on water or basked on beaches simply to gain warmth.

Numbers had also been temporarily affected by the 2011 floods that saw massive run-off from the land reduce food supplies for the herbivorous green turtles.

But he pointed out that while turtle populations had been "decimated" around the world, it appeared that, just as Gladstone Harbour was healthier than most people believed, there were "strong volumes of green turtles in Queensland".

However, he sounded a note of warning if the seas did continue to rise in temperature, as predicted would happen in the future as a result of global warming.

Mr McCosker said temperature was a determining factor in the sex of turtles, so an increase could cause a huge imbalance in males and females, with a consequent large-scale and rapid loss of population.

In this situation, a massive decline in their numbers would occur almost overnight.

"In just 10 years, we could go from thousands of animals to just a handful," Mr McCosker said.

More information: Click Here


 

Seagrass thrives surprisingly well in toxic sediments - but still dies all over the world

04 August 2015, University of Southern Denmark (Denmark)


Toxic is bad. Or is it? New studies of seagrasses reveal that they are surprisingly good at detoxifying themselves when growing in toxic seabed. But if seagrasses are stressed by their environment, they lose the ability and die. All over the world seagrasses are increasingly stressed and one factor contributing to this can be lack of detoxification.

Seagrass meadows grow along most of the world's coasts where they provide important habitats for a wide variety of life forms. However in many places seagrass meadows have been lost or seriously diminished and in several places, researchers and authorities work hard to understand what is happening and prevent the seagrasses from disappearing.

Now biologists from SDU add another important piece to the understanding of sea grass life.

It has long been known that the toxin sulphide is part of the threat to seagrasses. Sulphide is a naturally occurring toxin found in the seabed where seagrasses grows. The seabed is characterized by lack of oxygen and a smell of rotten eggs from sulphides.

A widely held theory states that seagrasses cannot tolerate sulphide and that increasing amounts of sulphide due to increased pollution have a negative effect on seagrasses.

Sulfide is absorbed by plant tissue
"But our research shows that seagrasses are actually capable of protecting themselves from sulphide. In fact, seagrasses benefits from sulphide", explains postdoc Harald Hasler-Sheetal who has conducted the research together with Professor Marianne Holmer, both from the Department of Biology, University of Southern Denmark.

The study shows that seagrasses are capable of protecting themselves against app. two thirds of the sulphide that enters the plant from toxic seabed. The last third is absorbed by the plant's tissue and here enzymes convert the sulphide into beneficial nutrients.

But the discovery that a seagrass can protect itself from sulfide does not mean that all is good.

"Seagrasses cannot tolerate sulphide under all circumstances. If a seagrass is stressed, the plant's capacity to detoxify itself will weaken, and the plant will be less capable of protecting itself from sulphide. It's like when humans are stressed; then we cannot perform optimally. Stressed seagrasses grow slower and may die back - this is what we see in many parts of the world", explains Harald Hasler-Sheetal.

Factors that may stress seagrasses, so it loses its natural ability to detoxify itself of sulphide include:

  • Unclear water: This blocks the sun's light, so seagrasses cannot produce enough oxygen to detoxify the sulphide.
  • Rising temperatures: If the water gets warmer, there is a greater risk of low oxygen in the water, which reduces seagrass' capacity to detoxify sulphide.
  • Discharge of nutrients: When fertilizers are washed from land into shallow coastal areas, many nutrients will be carried with the water. This stimulates blooms of phytoplankton, leading to shading and consumption of the oxygen in the water reducing the seagrasses capacity to detoxify sulphides.

How does seagrass detoxify itself?

Eelgrass roots (blue) that are surrounded by oxygen shield (purple)

Seagrass protects itself from sulphide in two ways: First it creates a shield around its roots so that sulphide cannot penetrate into the plant's interior. App. two thirds of the sulphide is being kept out this way. This shield consists of oxygen. The plant sends oxygen down to the roots and oxygen diffuse out of the roots. This oxygen shield can be maintained in daylight, where the plant produces oxygen via photosynthesis. At night oxygen is diffusing from the water to the roots. Part of the oxygen is also used to oxidize sulphide to sulfur, which the plant deposits as a harmless substance on the inside of air channels.

The last third of the sulphide is allowed to penetrate into the plant. This probably happens mainly at night, where the oxygen shield is smallest. Once inside the plant, enzymes convert the sulphide to useful nutrients for the plant.

If seagrass does not get enough oxygen, it cannot maintain these detoxification mechanisms.

More information: Click Here

Ref: PLOS ONE: Sulfide Intrusion and Detoxification in the Seagrass Zostera marina. Harald Hasler-Sheetal, Marianne Holmer. DOI: 10.1371 / journal.pone.0129136 June 1, 2015..

 

 

 

 

 

 


 

Scilly's Seagrass Beds 'Back To Normal' After 2014 Storms

03 August 2015, ScillyToday (UK)

 

Scilly’s seagrass beds are “exceptional” and amongst the best in the UK.

That’s the view of Dr Jim Bull, a volunteer researcher from Swansea University, who has been coming here every year since 2002 to measure the seabed around the islands.

The plant is an important indicator of the health of our marine environment, because it provides a rich habitat for a variety of sea life.

It’s the twentieth year that the study has been performed, and Jim says our seagrass beds are looking as lush and dense as ever.

And they’re as good as they were at the start of the study in the 1990’s, which is quite unusual, he says.

Around the world, particularly in the tropics, the plant is declining.

Jim says there was some concern here last year, because the seagrass “hadn’t really got going” after the winter storms early in 2014.

But he says that damage seems to have been reversed and the beds are “back to how they should be.”

However areas at Old Grimsby harbour are being damaged by increasing boat traffic and Jim says they’re “clinging on but suffering.”

Using fixed moorings can help, he says, because it avoids boats dragging their anchors in the beds, which causes the problems.

The other four sites being monitored are at Higher Town Bay off St Martin’s, Broad Ledge by Carn Near on Tresco, Little Arthur in the Eastern Isles and West Broad Ledge between Tresco and St Martin’s.

The density and length of the seagrass at each point is measured, and the types of organisms found there recorded.

But Jim says that doesn’t show the extent of the beds. He says they’d like to repeat the aerial photography they made in 2008 to see if that’s changing.

More information: Click Here


 
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