Hot, Leisure Summer Days and the Ocean

"When we get a deceased sea turtle in, our stranding investigations program here at Mote conducts a thorough necropsy and learns as much as they can about the animal."
"Right now, it's very strongly believed that the Florida red tide is playing a role in the sea turtle mortalities."
Hayley Rutger, Mote Marine Laboratory, Sarasota

"People have really beautiful yards in Florida, and we want to have all of these really nice things. But you know all of this comes at a price."
"It's alarming. I think we will see long-lasting effects from this event."
Gretchen Lovewell, manager, Mote Marine Laboratory, stranding investigations program

Fish, eels and turtles have died in Florida due to a toxic algae known as "red tide."

CBS News

Manatees, turtles and dolphins in the hundreds have washed up dead since 2006 in the worst case of red tide algal bloom, toxic to sea life and to any that ingest it, that has infested southwest Florida. Algal bloom occurs in places where there is an excess of nutrients. Where human waste, as an example, is poured directly into the sea without first being processed in sewage treatment plants. When untreated human sewage cannot be identified as the problem, fertilizer runoff from agricultural fields, along with farm animal waste creates the same toxic threat.

The rarest species of sea turtles in the world, the Kemp's ridley sea turtles, are being affected, with over 200 stranded in the red tide epidemic, with an almost complete mortality rate. Florida waterways have been fouled with red tide since last fall, caused by a tiny algae, Karenia brevis, known for the deadly toxin it produces. Although algae is an important part of any marine ecosystem, when extreme blooms caused by high nutrient levels result, algae responds by high reproduction rates.

According to the Florida Fish and Wildlife Conservation Commission, close to one hundred manatees have died since January, resulting from suspected exposure to red tide toxin. A dozen bottlenose dolphin corpses were recovered in one week alone, including one baby dolphin. Florida Fish and Wildlife Conservation and Mote collect and test the bodies, attempting as well to save animals close to death if they are recovered still alive.

They are housed in rehabilitation facilities to wait out the toxin passing through their body system, safe from further exposure while at the facilities. Life jackets and pool noddles are used to keep the manatees afloat to enable them to breathe at the surface of the rehabilitation pools. These ancient animals whose presence in the state is as primal as 26 million years in the past, are of the sirenian order of animals. Fittingly enough ancient Greek legend referred to them as sirens of the sea; mermaids.

The lifeless body of a West Indian manatee (also known as a sea cow) floats in the San Miguel river in Jonuta, Mexico, August 7, 2018. Across the Gulf of Mexico in Florida, 92 manatees have died since January, according to the Florida Fish and Wildlife Conservation Commission.

REUTERS/Luis Lopez

They are nearing the stage of being placed on the endangered species list with fewer than ten thousand of the West Indian manatees left worldwide. The death of some hundred of this species of which less than five thousand are present in Florida, represents an ecological disaster. The manatees' main food source is sea grass which toxic algae settles on. The toxin is capable of remaining in the environment even once the bloom has disappeared, and for weeks afterward, the manatees may remain in danger.

Both the turtles and the manatees are paralyzed by the algae's neurotoxin, causing their tissues to swell once the algae is ingested. That state of paralysis prevents the animals from swimming to the surface of the water to enable them to breathe, and drowning is generally the cause of death. Shellfish too become infected with the algae and that's usually when human health becomes impacted. The water itself may cause problems such as skin rashes, but eating creature infused with the algae is even more potentially serious, causing non-lethal symptoms such as numbness, tingling, loss of coordination, vomiting and diarrhea.

"These shellfish, over time, they accumulate high concentrations of these toxins, but it doesn't seem to affect them at all. Then humans come along and eat shellfish, and they get very sick." 

"A bunch of people get sick about the same time, same location, and you could track it back to the source. And that's how we discovered all these toxins. There's almost certainly other toxins being produced by these cyanobacteria that we have not discovered yet."

"If you see a bloom of cyanobacteria, you should simply assume it's got toxins in it. Don't go swimming in that water. Don't eat any seafood from that water."

"When you start feeding these things with all these excess nutrients ... now you've got what we call a 'harmful algal bloom'. Now you've got high concentrations of toxins, and now you're causing a lot of human health [problems] as well as destruction of the ecosystem and so on."

"This is not just a unique situation in Florida. This is a global problem."

Larry Brand, professor, marine biology and ecology, University of Miami Rosenstiel School of Marine and Atmospheric Science

Destroying an Invaluable Philippines Ecosystem

“It is vital not to let damaging fishing practices become the norm."
"Once people started using destructive fishing methods they stuck with what is familiar – even after those methods later became illegal. So, it’s essential to ensure young fishers engage with sustainable fishing methods such as hook and line fishing, or traps. It’s also critical to motivate older fishers to set aside destructive methods."
"If the Philippines were to fully implement its new fishing laws on sustainability, then ocean protection would improve and use of damaging gears would decline.:
"Fisher organizations can also take the lead, as sometimes happens in the Philippines, and cooperate on limiting destruction, ideally with support from local government."
Jennifer Selgrath, PhD student, Institute for the Oceans and Fisheries, Fulbright Scholar 

Squid fishers on Danajon Bank    ubc.ca/files Selgrath-Squidfishing

It seems hard to imagine but in the islands off the central Philippines, blast techniques are commonly used for fishing. A fisherman in a narrow boat will toss a bottle bomb into the water which explodes and the boat rocks while fish bob to the surface, dead mostly, others gasping briefly then dying. No fuss, big mess as coral shatters in response to the shock. The internal organs of reef fish are ruptured by the blast, their spines fractured, their flesh torn by coral shrapnel. And this is not a new kind of fishing technique, it is traditional.

Nothing survives the blast. Microscopic plankton, sea horses, anemones, sharks; in a 10- to 30-meter radius of such an explosion very little escapes death. The Philippines has been bestowed by nature to be the custodian of 27,000 square kilometers of coral reef, making for marine biodiversity on a grand scale. Now that climate change is racking up changes affecting oceans, the recognition that something must be done to stop illegal fishing, and most certainly 'blast fishing' from wreaking any more irreversible damage is beyond urgent.

Bacuit Bay and the town of El Nido seen from above. El Nido once suffered from rampant blast fishing. Credit: Lano Lin / Shutterstock

A new study out of University of British Columbia conducted in the Philippines by the Institute for the Oceans and Fisheres' Project Seahorse and the Landscape Ecology Group at the University of British Columbia, headed by Jennifer Selgrath, produced a paper: Shifting gears: Diversification, intensification, and effort increases in small-scale fisheries (1950 - 2010, published in PLOS One, concluding that such fishing methods cause greater damage to climate-endangered coral reefs than ever.


The researchers tracked various types of fishing methods — such as hand line, traps and nets — used on coral reefs between 1950 and 2010, to discover that from the 1960s the use of sustainable fishing methods such as traditional hook-and-line fishing remained stable, but that a marked increase in the use of fishing practices less selective, illegal and more destructive had moved forward, particularly in the regional use of destructive fishing methods such as the use of explosives and poisons, both outlawed by government in 1932.

Despite legislation in the Philippines dating after 1998 banning these destructive fishing techniques their use persists with a growing number of fishers making use of crowbars to smash up corals to enable them to catch elusive marine animals such as abalone which bring greater profits. For many traditional fishermen the profit they obtain ensures they will continue to defy the law; if their ancestors did it, it can't be wrong. Basically, these fisherfolk live a poverty tradition, barely managing to sustain themselves.

Legal net fishermen gain three kilos of fish daily. Dynamite fishing can net nine kilos, occasionally up to 20 kilos. Slice off a few centimeters of fuse wrapped in aluminum foil, strap on a match for a detonator; funnel sand to the bottom of a glass bottle and pack it with explosives. That fuse, in aluminum wrap, allows four seconds to toss the bomb and wait for it to explode. It helps to preserve human life to know the proper bomb-making technique; some fishers have been killed or maimed through carelessness or distraction.

In 1970, according to a report by the Philippine national statistics board, an average daily catch was 20 kilos, reduced to two kilos by 2000. Declining fish stocks convinced more fisherfolk that they would do better through illegal fishing. In blast fishing the entire food chain -- plankton, small and large fish -- juveniles that will never attain to spawn size, perish. Absent healthy corals the entire ecosystem along with the fish within fail to flourish and gradually die off.

Rubber hose wedged between teeth, fishermen sink ten meters into the water after a blast to lurch awkwardly along the ocean floor, collecting stunned and dead fish scattered among broken coral. In twenty minutes surfacing with a  handful of high-value reef fish and about five kilos of scad and sardines, a small catch completes the process. Two men can split the earnings from that catch, about $10 profit each.

Coastal resources management in various island regions have limited resources at their disposal; a handful of slow-moving boats to patrol hundreds of square kilometers of sea. Dynamite fishermen reason their parents used this method and there are still fish; if the scientists warning of disappearing fish were right the fishermen would themselves die if the oceans ran out of fish. However that would never happen, the fish will never disappear, they believe.

In a matter of seconds, dynamite fishing can destroy a reef that took hundreds or thousands of years to grow.

Photo Credit: Richard Whitcombe / Shutterstock

Interfering With Nature's Designs

"Researchers recently studied three islands to record the effects of rabbit invasion [on the Kerguelen Islands]. The island of Grande Terre has many rabbits, while Ile Guillou’s rabbits were eradicated in 1994, and Ile Australia never had to contend with the beasties at all. In areas where rabbits thrived (and they did, without predators) native plant diversity declined and burrows made the land susceptible to erosion. In particular the researchers noted that soil fungi were very different on the two islands that had or have rabbits. Even 20 years after the rabbits left, Ile Guillou’s plant and fungal communities resembled that of Grande Terre."

"The long-lasting effects could have come from disturbance of the soil through burrowing, rather than any specific rabbit-additions such as feces. A different disturbed soil site on Ile Australia showed some similarity to the soil fungal communities on the rabbit-affected islands. Native plants might be slow to grow back after such disturbance."

"However, the study does point out that some subtle effects of an invasive species can persist for a long time after the problem animal or plant is gone. Helping an ecosystem recover from such a change may be trickier than previously thought."

Smithsonian

"The big lesson is that sometimes we can have a strong human impact even in places that are very, very isolated."
"Our research shows that we absolutely have to act immediately. There is no lag time between the arrival of these invasives and the impact."
G. Francesco Ficetola, biologist, University of Milan

The European rabbit looks harmless, but in the Kerguelen Islands, the species became invasive. A new study finds that the effect of the rabbits on soil fungus lasts even long after they are gone.

There is remote and isolated and then there is truly and really isolated-remote on this planet of ours. At one time Antarctica was the sole place left on Earth, an entire continent, that hadn't been 'discovered'. Its presence was known to whalers, but explorers from Britain and Norway had not yet set their sights on travelling to that remote region and undergoing privation in the extreme South Pole geography to map it out and discover the lay of the terrain, its mountains, glaciers and environmental conditions.

As it happens, there is a geographic area, one of isolated islands, discovered by a French expedition in the late 16th Century, acknowledged to be a French possession now, that was once a way-station for sealers and whalers and their hardy crews. Whales were once hunted for their baleen, the long bone-like structures through which they sift the marine life they scoop up as fodder for those great beasts; the baleen used for Victorian-era ladies' undergarment stays. Seals were traditionally hunted for food, household oil and sealskin garments by the Inuit, and in the 19th Century represented a much-in-demand European trade item.

On the Kerguelen Islands, literally at the world's end in the southern Indian Ocean between Madagascar and Antarctica, there is a research field station, and not much more, for its climate is extreme, and the landscape is unremittingly harsh and windswept. The islands’ average daytime high temperatures nudge at 11.5° C (about 50° F) including during the summer. It experiences, 300 days a year, rain, snow or sleet, and sustained winds of up to 150 kilometers per hour (93 mph). The environment is, to say the least, unforgiving.

But rabbits found it to their liking; once brought to the islands, purportedly in an effort to make the landscape more interesting, and possibly also to provide an alternate fresh food source for sealers and whalers, who made the islands a way-station; rabbits thrived and proliferated, and in so doing, like any introduced species alien to the environment, found no natural enemies and sufficient nutrition growing out of the soil to sustain their colonies, and then some.

( Worm That Turned (CC BY 3.0 via Wikimedia Commons))

Scientists, in 1974, who felt the remote archipelago represented a promising spot from which to observe the transit of Venus as it regularly passed before the sun, installed an observatory on the 93-mile-wide Grande Terre, the main island. They too were linked with bringing rabbits with them, an estimated five; again as a potential food source for the future. By the time the researchers left the island, the rabbits had begun their work of reproducing in sufficient numbers to alter the ecosystem. 

 

That, in any event is what a report recently published in the journal Science Advances, has noted, based on sediment cores drilled from a small lake in Grande Terre's central plateau. The question of how invasive species change ecosystems intrigued the scientists who examined those cores, and the Kerguelen Islands represented a natural laboratory, distant from civilization and its presentation perfect for investigation.

 

The biologists extracted DNA from the sediment cores and pieced together a timeline of what lived on the island over the course of hundreds of years, with the genetic data indicating the central plateau of Grande Terre with a stable ecosystem until about 1940, when the rabbits reached that area on the main island. A cushion-like plant named Azorella Selago dominated the area originally, but with the introduction of rabbits, the presence of native plants diminished and erosion began its destructive work.

Now, to add to the severely deleterious effect of the exploding rabbit population, climate change has also entered the picture, to impact doubly negatively on the original ecosystem. Dr. Kerguelens points out that what happens on an isolated group of islands is reflected by alterations in ecosystems throughout the entire planet; with the arrival of invaders, normalcy and stability erode.

The Kerguelen Islands are an important breeding ground for Antarctic Fur Seals. Credit: Liam Quin

Freshwater Lake Acidification

"We're monkeying with the very chemical foundation of these ecosystems."
"But right now we don't know enough yet to know where we're going. To me, scientifically that's really interesting, and as a human being a little bit frightening."
"I'll probably put my money on increased variability from lake to lake. They're just going to be more extreme."
Emily H. Stanley, fresh-water ecologist, University of Wisconsin Madison

"Many fish are not able to detect their predators anymore. They can even get more bold."
"I discovered there was no information [on carbon dioxide levels in fresh water]."
"We didn’t really know what to expect. But the speed of acidification we find is quite fast."
"I think this study we’re publishing is like a door-opener. I hope there will be other scientists who will follow."
Linda C. Weiss, aquatic ecologist, Ruhr University Bochum, Germany

The Sorpe reservoir in northwest Germany, one of four freshwater reservoirs observed in a recent study that found that carbon dioxide absorbed in lakes, rivers and streams can affect entire ecosystems. Credit Mauritius Images GmbH/Alamy

It's not yet clear whether lake waters across the globe are building up carbon dioxide. A study was published in November by Dr. Stanley and colleagues setting out carbon dioxide levels in Wisconsin lakes. The study concluded that no significant change whatever was detected between the years 1986 and 2011. All lakes take in carbon dioxide from the atmosphere, some drawing it in from the soil around lakes and some lakes may have quite a lot of underwater plants that take up the gas, while others harbor microbes releasing more of the carbon dioxide.

Over  time, levels of carbon dioxide can undergo dramatic alterations, in any body of water. Time alone, over the passing decades will determine the level of its presence, as carbon dioxide continues to take its fuller presence in the atmosphere. As the levels progress upward, Dr. Stanley has speculated that the actual presence and what it fully portends will become more nuanced. What is certain at the present time is that very few ecologists have studied the presence of carbon dioxide levels in fresh water.

And that is because it has been the presence of sulfuric acid and allied pollutants that have gathered in freshwater lakes as a result of acid rain, including the environmental impacts of runoff from agricultural lands into lakes that have historically presented as a concern. Variables such as water temperature and the organic carbon contained in a lake also come into play in determining the presence and level of carbon dioxide in lakes.

From 1981 to 2015, Dr. Weiss and her colleagues determined the levels of carbon dioxide in four reservoirs in Germany. Their findings were published in the journal Current Biology, making it clear that amounts throughout that period of time had tripled. Back in the 1980s, oceanographers were continuously measuring carbon dioxide in seawater, chronicling a steady rise, lowering the pH of seawater, so it became more acidic, interfering with chemistry coral use for their calcium skeletons.

Chemical changes in water interfere with marine organisms' ability to find food and to avoid danger. The researchers, curious about the effects on freshwater life of the presence of carbon dioxide, ran experiments on water fleas. These are minuscule creatures filtering algae and microbes from water and they in turn are eaten by small fish, which in the natural order of nature's design, are then devoured by ever larger fish. Were the presence of carbon dioxide to affect the bottom of the food chain, the entire lake ecosystem could be influenced.

Nature has equipped water fleas with a unique capacity to make themselves more difficult to consume, in response to sensing chemicals in the water related to the presence of fish nearby. Some of the water fleas grow a crest on their heads, and others sprout self-defensive spikes, making them less palatable to the fish, and more difficult to swallow. High levels of carbon dioxide resulted in water fleas producing smaller crests and shorter spikes, Dr. Weiss discovered. She reasoned that the presence of carbon dioxide interferes with the water fleas' nervous system, decreasing their capacity to detect predators.

At top right, a water flea with its protective crest; at bottom right, a water flea with “neckteeth.” These defenses may be blunted by chemical changes in water. Credit Linda Weiss and Sina Becker

This new research addressing the question of how much carbon dioxide might harm freshwater life has impressed Caleb T. Hasler, a biologist at the University of Winnipeg in Manitoba. He and his colleagues studied minnows in water rich with carbon dioxide, discovering that the fish fail to respond as swiftly to alarm signals that other minnows release. His team studied two species of mussels, one which relaxed its muscles in high carbon dioxide presence, leaving its shell gaped open. While the other clamped its shell tight shut rendering it unable to filter food.

The filtering actions of mussels are responsible for maintaining clear water in a lake. Such changes as have been detected may in the final analysis impact upon entire ecosystems. "You can have lakes where the carbon dioxide increases tenfold at night", observed Dr. Hasler.