Day 72

Yesterday was an amazing day!  We started out with a tour of the mangroves in Lac Bay, on the east side of Bonaire.  Mangroves and seagrasses, which both grow in Lac Bay, are important habitats for baby fish.  They use the seagrass as a nursery because the grass provides protection from predators, but as they grow larger they need bigger protection, and so they move into the mangroves.  Without the seagrass and mangroves, there are no baby fish, and without baby fish there won't be any big fish, so they're pretty important!  Mangroves also protect the land from erosion and can help protect against storms, which makes them important to humans.

We kayaked through the mangroves with our guide, Hans, who also took us cave exploring.  The mangroves are full of birds, fish, sponges, algae, and upside-down jellyfish!  Upside-down jellyfish lay upside down because they have little animals called zooxanthellae living in their tentacles.  The zooxanthellae get protection from the jellyfish, but they need light to photosynthesize and provide food for the jellies, which is why the jellyfish lay upside down.  The tentacles are the only part that stings, so you can reach under them and flip them over!  I flipped a few jellyfish and had fun petting them.  They were slimy!

After the kayak tour we went for a snorkel in the mangroves.  We had a surprise--tons of box jellyfish!  They were smaller than I expected, hard to spot, and all over the place.  Fortunately nobody got stung, although I hear they aren't as bad here as they are in Australia.  We collected algae samples to identify in the lab, which was... slimy.  The mangroves were full of fish and jellies, and I even got to see a Caribbean spiny lobster.  The lobsters here don't have claws but they are huge.  The body of the one I saw was over a foot long, and with its long antennae was definitely over two feet.

We captured a box jelly and brought him back to the lab!

 At 18:30 (that's 6:30pm for Americans) we boarded a boat for our night dive to see ostracods spawning!  Ostracods are tiny crustaceans that produce bioluminescent light for defense against predation, but here in the Caribbean they also light up for mating!  They rise to the surface and spin around quickly to attract mates.  We boated over to our intended site, Andrea I, but the current was so incredibly strong that we were kicking as hard as we could just to stay in one spot.  We reboarded the boat and tried another site, Petries Pillar, and were happily surprised to find that the current was much less powerful there, so we hopped in and turned off our flashlights to see the show! 

Now the ostracod spawning was neat on the surface, but underwater it was incredible!  They live on the coral and their gametes are also bioluminescent, so during spawning it looks like little bubbles of light are rising from the corals.  The only way I can describe it is this: it's like you're floating in deep black space, surrounded by thousands--maybe millions--of small, slowly-rising stars.  It was absolutely magical.  After a few seconds they lose their glow, but with just a wave of a hand or fin you can stimulate the particles to light up again--I think gives them mechanical energy to turn into chemical light energy.  Bioluminescence is pretty awesome!

Not much else has happened in the past week, so for now I'll leave some flamingo pictures I took last week.

 

Juvenile flamingos are gray!  They don't turn pink
until they become adults.

Two adults, a juvenile, and (possibly) an egret?  Or a heron?