Tag Archives: Nature

Coral Reef

This post was triggered by two events – one was a talk about coral reefs at a recent International Womens Club lunch (yes, I have become a woman who does lunch) and the other a wander along the coastal section of a nature reserve to the east of the island that was littered with huge chunks of old and rusted metal, possibly from metal barrels or vehicles.  So yesterday I listened to two lectures on iTunesU about coral reefs (iBioSeminars, Dr Knowlton from the Smithsonian Institute).

Bermuda is the northernmost coral reef at 32 degrees north, sitting on top of a very very old volcano.  The sea mountain itself is basalt but it is topped with limestone made by organisms that fix calcium carbonate from the water such as corals.

 

 

What exactly are corals? 

Definitely animal, and the individual in the colony is called a polyp.

Image

One I prepared earlier!

 

The polyp is effectively a column with a mouth at the top, it is radially symmetrical.

They all have nematocysts – harpoons of sting cells to catch prey.

Inside the coral is a community of algae, bacteria, archaea, fungi and viruses, which are essential for the health of the coral.

 

Zooxanthellae are algae that live in corals  – under the microscope they look like small green balls. They use sunlight to make sugars that the corals can use to grow.

 

 

Image

Coral animals are hard to classify – even for the experts.

They all belong to the Phylum Cnidaria

Not all of them will make rock, some serve as anchors or to attract fish.

There are different kinds and four groups make stony skeletons:

True corals, Blue corals, Organ pipe corals, Fire corals (this one hurts lots)

Fire Coral: Millepora alcicornis

Then there are sea fans and soft corals which don’t build rocky skeletons.

They grow in complex shapes and one family can make several different shape colonies.

Corals do actually reproduce sexually, releasing eggs and sperm in a mass spawning event that occurs a set time after the full moon – the timing is down to a specific hour after sunset and studies have shown for example that one species will spawn at two hours after sunset and then another species on the same night but four hours after sunset.  Such tightly controlled reproductive life would be something of a bind for humans.

This next bit is important: 

Coral reefs face risks as great as that for the rain forests  

The risks come from:

  • Pollution
  • Overfishing
  • Rising sea temperatures
  • Coral diseases 

All of these lead to a process called coral bleaching.

Coral bleaching is destroying the coral reefs around the world.

It is named “bleaching” because the corals lose their colors.

It occurs when the algae get stressed and stop photo synthesizing.

They are stressed when it is too hot, too sunny, or the water is too acidic.

So the algae die and the coral spits them out – so instead of seeing the algae inside you can see through the polyps to the stony skeleton which is white.

Without the algae the coral cannot build skeletons so cannot grow.

 

Image

Bleaching of coral. Photo from The Royal Gazette

The coral in the right side is bleached.

One cause of bleaching I had not fully appreciated is sun tan lotion where the ultraviolet filtering chemicals dissolve in the water in as short a time as fifteen minutes.  Biodegradable sunscreens are apparently available (Badger; Caribbean Solutions) so will be on my shopping list for next summer.

Corals also suffer from diseases, with unimaginative names such as “white band disease” and “black band disease”.  But as yet it isn’t known which bacteria or viruses might cause the diseases because they don’t yet know the normal microbiological life in coral. There are over 6000 identified species of coral bacteria!

One of the theories of coral disease is linked to seaweeds producing sugars that get absorbed into the coral which cannot handle them – diabetic coral if you like.  It is a problem because of seaweed overgrowth where weed-eating fish have been decimated by overfishing.  They have documented coral reef destruction with increasing density of seaweeds in the reef area.  Seaweed grows much faster than coral and so tends to take over pretty quickly.

 

Coral reefs are being lost at a rate of 1-2% per year.

Why does it matter? 

For Bermuda,

  • The reef protects the island from the force of tropical storms – without it each hurricane could be as damaging as Fabian was in 2005.  
  • The reef provides a habitat for commercially important fish 
  • Recently there has been pharmaceutical interest – some species of cone snails that live on the reefs can produce analgesics. 
  • Being the most northerly coral reef, thousands come to the island to see the reefs and fish. So loss of the reef would seriously damage  Bermudian economy. 
  • The reef is a natural boundary that protects the shoreline from the power of the waves – inside the reef the waves will be typically several feet lower and so less coastal erosion occurs.

For other places such as the Phillipines some areas are highly dependent on the reef for food and employment, so their economies would be seriously affected by loss of the reefs.

What can I do?

  • Take only pictures, leave only bubbles.
  • Choose my seafood wisely – only sustainable fish
  • Don’t buy coral jewellery
  • Reduce, reuse and recycle
  • Plant a tree – trees reduce run off into the oceans
  • Take away my own rubbish, but also pick up a piece of other rubbish each time I visit a beach
  • Stay informed and spread the word …

 

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Formica

I woke to freshly brewed “proper” coffee and the question “Where’s the baby powder?”
Post-dream disorientation took me back 25+ years: babies, nappies, feeding, changing… let me go back to sleep, please. But now we keep baby powder for the ants.

The ants have found their way into the kitchen. 20130702-115541.jpg

This isn’t actually my kitchen, the kitchen ants are not photogenic, these ones are to be found on the path outside, every day running back an forth along an invisible scented line.

They are quite small, well of course ants are, but to me they appear smaller then the UK ants. Pheidole megacephala – big-headed brown house ant. Like the English ants it is a member of the Formica family (nothing to do with laminate worktops) but the Bermudan ants seem to have two-segment waists while UK ones have single segment middles (petioles).

Until today I had no idea there are so many different ants:

http://en.wikipedia.org/wiki/List_of_ants_of_Great_Britain

The “bigheads” were first found in Mauritius and its a long way to Bermuda so I guess they travel well; in fact it is listed in the top 100 most invasive species. There are two types of worker ants in this species: Soldier ants with the biggest heads, about 4mm long, and Minor worker ants that are half the size and whose heads are relatively smaller. I think the ones in my photo above must be minor workers as none of them seem to have large heads. They feed on dead insects – I have been advised that they will congregate around dead cockroaches but that I should first trace the line of ants back to their nest before moving the cockroach and then spray the nest.

20130702-115646.jpg

Wellcome Images

I am told you can still buy DDT in Bermuda; banned in US in 1970s and UK in 1984, but still manufactured in India and still used to fumigate homes in some places in the world.
For the medical audience, it works by opening sodium channels in neurons, which for the ants means spasms and death. The toxic effects on humans include endocrine effects, it is an anti-androgen, and direct effects on the genes, hence is a carcinogen. The DDT story is as much political as it is science and the ban is as controversial as its continued use in some countries. Paul Mueller, a Swiss biochemist, received a Nobel prize in 1948 for his work on DDT and it did prevent millions of deaths from Malaria.

The following have all been recommended to me to get rid of ants:

Mint leaves…. apparently they dont like the smell
Cayenne pepper….the capsaicin in cayenne pepper is an irritant to ants
Baby powder….the cornstarch in baby powder is irritant
Cornmeal …makes ants explode: they take the grains home, eat them and then presumably drink some water so grains expand inside the ant, and then they go pop – but might take an awful lot of cornstarch to feed a whole colony
Cinnamon ….but some people dont like the smell any more than the ants
Bay leaves … not very tidy
Vodka. …. 3:1 ratio of vodka to water, sprayed liberally, but might give visitors the wrong impression
Washing-up liquid and water mix ….works for a while but then they come back when it has dried

We have settled on baby powder, as you have surmised from my wake-up call. I have no idea where the houseproud urges came from as I never had them in UK, but I am resisting the inclination to hoover it all up as soon as the ants take a break. The smell brings back some of the nicer memories of having children, it is relatively cheap and so far I haven’t heard any suggestion that it is carcinogenic….

Update on that: baby powder does contain talc which a recent meta-analysis suggests is linked to ovarian cancer

http://www.dailymail.co.uk/health/article-2343974/Women-regularly-use-talcum-powder-increase-risk-ovarian-cancer-24.html#

(Daily Mail version)

http://cancerpreventionresearch.aacrjournals.org/content/early/2013/06/12/1940-6207.CAPR-13-0037.abstract

(Academic link)

OK so keep it well away from “intimate personal hygiene”, probably still safe for ant prevention.

I mentioned cockroaches earlier, the Periplaneta americana.

 

After fruitless search for one to photograph I have resorted to that well-known w…pedia for a picture. They eat anything that is not alive and are common in basements – guess who isn’t going to unpack the cardboard boxes when it is time to return to UK! I havent actually seen a living one out here yet, I am assured it is only a matter of time, and I rather wish it would happen so I can get over it as the apprehension at meeting one in the bathroom at night grows with every night I escape unscathed. I like the friendly name given to them here: Palmetto bugs.

On my search just now I did find this:

20130702-115705.jpg

It think it is a June Bug (Lygyrus cuniculus ) which apparently fly drunkenly at night in June (obviously), but it doesnt look exactly like the one in my field guide book so I might be wrong. Any suggestions?

There are many prettier and less annoying insects and bugs, butterflies, millipedes and snails, but none of these are threatening my kitchen so not priority no1.