Intertidal zone–and crabs– at high risk from climate change, study says

Climate change, which will raise ocean temperatures and more carbon dioxide in the atmosphere which will increase the acidification of the oceans will have the greatest affect on the intertidal zones—and a key indicator species, crabs and similar creatures.

A study by San Fransisco State University published today in the Journal of Experimental Biology used the small (usually 15 millimetre) porcelain crab  to simulate the conditions that will come to the intertidal zone and affect other species including the larger dungeness crab. ( According to Wikipedia, porcelain crabs are an example of carcinisation, whereby a non-crab-like animal,in this case a relative of a squat lobster evolves into an animal that resembles a true crab.)

A porcelain crab (Nick Hobgood via Wikipedia)
A porcelain crab (Nick Hobgood via Wikipedia)

Studies have shown that as climate changes, coastal ecosystems will be see “have increased extremes of low tide-associated thermal stress and ocean acidification-associated low pH.”

The study by co-author Jonathan Stillman and his colleagues, is the first to explore intertidal zone organisms’ response to combined variation in temperature and pH, which is expected to intensify in the future due to climate change and ocean acidification.

The current and previous studies have shown that during low tide, air temperatures in the intertidal zone can fluctuate dramatically as much as 20 degrees celcius over short periods of time up to six hours. Temperatures can reach extremes when low tides coincide with hot days. Marine intertidal organisms tolerate these natural temperature fluctuations, yet it is known that they are limited in their scope to tolerate future warming.

In the simulation porcelain crabs  were placed in a specially built aquarium designed to simulate the natural environment, including tidal changes. At low tide, with the crabs exposed to the air, the researchers varied the temperature to mirror day-to-day changes the crabs currently experience — such as cooler air on a cloudy day and warmer air on a sunny day — as well as conditions expected in the future. At high tide, with the crabs submerged, they adjusted pH levels in the same fashion.

As the temperature rose and pH levels dropped — conditions expected in the future due to climate change — the crabs’ ability to withstand heat increased. But at the same time, researchers found, the crabs’ metabolism decreased. In addition, the combined effect of higher temperatures and lower pH levels was greater than the effect of either of those two factors alone.

“When you combine these things together, they slow down metabolism, which means crabs become sluggish and have less overall energy to do things like growth or reproduction,” Stillman said. “If their whole energy budget is a pie, then in the future the size of the pie is going to be smaller, and a larger percentage of it is going to be taken up by survival and maintenance.”

The study says that although porcelain crabs are not particularly important to humans — they are not fishery crabs such as Dungeness — they are an important food source for coastal fish, birds and other crabs.

The results suggest “there is a potential for adverse long-term ecological consequences for intertidal ectotherms”– that is creatures that depend on the external temperatures to regulate body heat– “exposed to increased extremes in pH and temperature due to reduced energy for behavior and reproduction.”

The porcelain crabs can also be seen as a model for scientists to understand the impacts of climate change and ocean acidification on crustaceans in general, Stillman said. Future studies will look at the impact of varying temperature and pH changes on different species of porcelain crabs, juvenile crabs and crab embryos.

Oil spill dangers can linger for 40 years, report shows

Genivar report
Cover of Genivar tanker report (Transport Canada)

The Genivar report for Transport Canada on oil spills say that some persistent effects can last for more than 40 years, based on a study of a spill in Cape Cod, Massachusetts. The report  notes that persistent sub-surface oil is still a problem at Prince William Sound, site of the Exxon Valdez disaster in 1989.

On long-term effects, Genivar reports: “The ingestion of contaminated food (such as oiled mussels), may represent the most important exposure pathway for aquatic fauna during a chronic
phase. Chronic exposure to contaminated sediments is also important for fauna or
vegetation.”

 

 

 

It goes on to stay that “large-scale oil spills might have considerable long-term
consequences on social structure and public health, interfering with traditions and
causing cultural disruptions.”

It appears that in the case of an oil-spill, time may heal some wounds, but not all of them, at least if time is considered within human lifetimes and the lifetimes of other species.

Ecological recovery is measured by how quickly individuals and populations of
species return to pre-spill conditions. It is determined by factors such as oil type,
exposure duration, water temperature, degree of weathering, spill response and the
individual and species-specific life history traits. In most environmental habitats,
recovery is completed within 2-10 years after a spill event, but in some exceptional
cases, such as in salt marshes, effects may be measurable for decades after the
event.

In the case of the Exxon Valdez oil spill in Prince William Sound… in 1989, the persistence of sub-surface oil in sediments and its chronic exposure continues to affect some of the wildlife through delayed population reductions, indirect effects and trophic interactions 20 years beyond the acute phase of the spill.

It then goes on to stay that

Four decades after the oil spill In Wild Harbor (USA), Spartina alterniflora beds had a reduced stem density and biomass and mussels in oiled locations showed decreased growth and filtration rates.

According to a Boston Globe story, published at the time of the Deepwater Horizon oil leak in the Gulf of Mexico, in 2010, the Wild Harbor, an oil barge ran aground near Cape Cod in September, 1969, spilling 200,000 gallons of fuel, some of which is still there.

The Boston Globe story noted:

Today, Wild Harbor looks much like any other Cape Cod marsh, but the oil below the surface affects its resiliency. Fiddler crabs normally burrow deep down, funneling oxygen to the roots of marsh grass. Here, they stop digging when they reach the oil, turn sideways, and burrow back to the surface. They also act “drunk’’ from the oil they ingest, and predators can catch them more easily, research shows.

The Woods Hole Oceanographic Institute has been studying the Wild Harbor spill for the past 40 years.

At a recent conference, Dr. John Teal updated scientists on the “multi-decadal effects” of the Wild Harbor spill. According a blog on the conference:

At the time of the 1969 spill, lobsters, clams, and fish died by the thousands, but most people believed the harm would be temporary, reflecting the conventional wisdom of the time. Barge owners and oil industry experts even told residents that most of the oil would evaporate and any damage would only be short-lived. However, researchers at WHOI were not so sure and immediately began cataloging species and tracking where the oil was and kept at it for years. The researchers understood that the immediate, short term effects of oil pollution were already obvious and fairly well-understood, but that everyone was rather ignorant about the long-term and low-level effects of an oil spill….

Beginning three to five years after the spill, marsh grasses and marsh animals were again occupying most of the oiled area. An observer unfamiliar with Wild Harbor would not have been able to visually detect the oiled areas after just 10 years, and by the second decade after the spill, the marsh’s appearance had returned to normal. However, the WHOI researchers pointed out that for more than a decade after the spill, an oil sheen still appeared on the surface of the water when mud from the most heavily oiled parts of the marsh was disturbed….

In 2007, WHOI researchers documented that a substantial amount of moderately degraded petroleum still remained within the sediment and along eroding creek banks of the marsh oiled in 1969. They also demonstrated that the ribbed mussels that inhabit the oiled salt marsh, and are exposed to the oil, exhibited slower growth rates, shorter mean shell lengths, lower condition indices, and decreased filtration rates even when placed in a healthy marsh. Researchers have also documented detrimental effects of the 1969 oil spill on the salt marsh plants themselves.

 

Related Oil Spill on the Wild Harbor Marsh by John M. Teal and Kathryn A. Burns
The Genivar report goes on to note:

Long-term effects on the population in the aquatic environment (especially on mobile fauna) are especially difficult to confirm. Benthic [bottom dwelling] invertebrates may be more at risk than fish species due to the fact that more or less sessile organisms are likely to suffer higher initial rates of mortality and exhibit long recovery times as a result of
exposure to oil-saturated habitats.

Nearshore demersal [bottom-dwelling] fish can also suffer from long-term chronic exposure, as indicated in masked greenlings and crescent gunnels by biomarkers on hydrocarbons 10 years after the Exxon Valdez spill. Mortality in sea ducks and sea turtles due to chronic exposure was also reported many years after the spill and other results indicate that effects on cetacean populations can last beyond 20 years after the acute exposure phase.

As for the recovery of the economy after a spill, Genivar notes it is based “on the time required for effected industries to be fully restored to pre-spill conditions.

The length of time required is influenced by the duration of the aquatic area closures (e.g. commercial fisheries, recreational fisheries), the public perceptions on seafood safety and the perceived effects of the aesthetic quality of the environment. Even after the full ecological recovery of the aquatic resources, fisheries can be far from reestablished, as is still the case for herring fisheries in the Exxon Valdez spill area…

As reviewed by Genivar, negative perceptions associated with the quality of fishery products, even for fisheries that have not been contaminated and also for regions not directly affected by the spill, can be far more important than the direct economic losses. This also holds true for the tourism sector and all other related spinoff sectors.

Clio Bay remediation project “killing two birds with one stone,” Ross says

Special report: Clio Bay cleanup: Controversial, complicated and costly

 

Ellis Ross
Haisla Nation Chief Counsellor Ellis Ross at Bish Cove, June 19, 2013. (Robin Rowland/Northwest Coast Energy News)

Haisla Chief Counsellor Ellis Ross says that capping the logs at Clio Bay was a Haisla idea, taking advantage of the opportunity to use the marine clay from Bish Cove to bring back the Clio ecosystem.

The Haisla were told by experts who video taped the bottom of Clio Bay that are between 15,000 to 20,000 sunken logs in Clio Bay.

“I know because I’ve spent a lot of time down there plus my dad actually worked for the booming company for years and knew what was going on out there,” Ross said. “There are two extreme areas we’re talking about, if you look at Clio Bay where it’s estimated that there 15,000 to 20,000 logs down there, imagine what Minette Bay looks like? And it’s all iron, it’s steel. It’s not just wood, there are a lot of cables down there.

Retrieved cables
Cables retrieved from Ward Cove, Alaska, during dredging and capping in 2001. (EPA)

“The Haisla have known about the degradation of our territory for years. The problem we have as Haisla members is to restore the habitiat is that nobody wants to clean up the habitat. This was our idea, after review from technical experts from DFO as well as our own experts. We’re looking for a three way solution, with the company, DFO and the Crown and the Haisla.”

“I’d love to go and catch halibut and cod, like my ancestors used to.”

He said that the Haisla have beem aware of environmental problems from sunken logs for decades and have been asking for cleanup of degraded areas since 2004, not just at Clio Bay, but in the Kildala Arm and at Collins Bay, which were studied by DFO in 1997.

“The logs are down there, they are oxidizing, but no one wants to do anything about it, including the company and including the Crown. We had independent people come in and review it and have them come up with a recommendation. There was a small scale project [involving marine clay] that proved that this could work.

“This system here is killing two birds with one stone, get rid of the clay and try to remediate some of the habitat,” Ross said.

He said that the original estimate of marine clay excavated at Bish Cove was 10,000 cubic metres. That has now risen to about 3.5 million cubic metres because the KM LNG project is digging deeper for the foundation of the LNG terminal. The original plan called for disposing 1.2 million cubic metres at sea and another 1.2 million cubic metres on land.

“The original idea was to dump the clay in the middle of the ocean. In small amounts it could have been mitigated, but in large amounts we said ‘no.’ If we try to dump clay in the middle of the channel, we have no idea where it’s going to end up, what the effect is going to be.” Ross said. “We did the same thing here for the terrestrial side, we said ‘OK that with the rock quarries above Bees Creek,’ use the clay to help remediate that as well, bring it back.”

Asked about Ward Cove in Alaska, where the US Environmental Protection Agency ordered a cleanup, Ross said. “The difference here is that no one is ordering these companies to clean up the sites, they walk away. No one is taking responsiblity, The Haisla are trying to do this within the parameters they’ve given us.So if someone could come in and order these companies and do something, we’ll look for something else to do with the clay. Until that day comes, the Haisla are still stuck with trying to bring back this land by ourselves. If the District of Kitimat wants to pay the bill, great. Let’s see it.

“We need to put pressure on the province or Canada to cleanup these sites. We’ve been trying to do this for the last 30 years. We got nowhere. Before when we talked about getting those logs and cables cleaned up, it fell on deaf ears [at DFO]. They [DFO] had no policy and no authority to hold these companies accountable. So we’re stuck, we’re stuck between a rock and hard place. How do we fix it?”

Ross also noted that Shell’s LNG Canada project also faces remediation problems, “Shell is going to have the same problem, their’s is going to be different, they’re going to have get rid of contamination on the ocean bottom and beneath that it’s basically going to be gravel, it’s not clay, they’re going to have get rid of that product.”

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Clio Bay: Links and Documents

Links and documents relating to sunken logs and site remediation

Note many, not all, external links are to pdf files.

Canada

DFO study of sunken log sites in Douglas Channel

DFO Study Dissolved oxygen cycle in Minette Bay

Impact of Wood debris in British Columbia estuaries

Chris Picard’s study of Clio and Eagle Bays as posted on the University of Laval website

United States

Links

Alaska Department of Environmental Conservation

Environmental Protection Agency

Ketchikan Paper Company
This is the EPA Web site on the Ward Cove cleanup and remediation with numerous documents.

EPA capping guidance
EPA contaminated sediment capping guidance

US Army Corps of Engineers

US Army Corps of Engineers capping guidance

Documents

Alaska log site remediation guide  (pdf)

EPA study of dissolved oxygen in Ward Cove (pdf)

Marine Log Transfer Facilities and Wood Waste (pdf)

Academic paper by Ward Cove consultants Geramano & Associates on sediments in Ward Cove and Thorne  Bay, Alaska.

Ward Cove Sediment Remediation Project Revisited

Academic paper by Ward Cove consultants Integral Consulting

 


 Other Links

Kitimat LNG (KM LNG)

Stantec

Stantec remediation project page

Integral Consulting

Integral Consulting Ward Cove web page

Exponent 

Exponent Ward Cove web page

Exponent LNG Safety web page

Germano & Associates

(Note not all documents used in this report are available online. Some sent to NWCEN are too large to upload)

 


 
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