Diving the Anchor

Checking out the anchor is not usually a pretty dive, but it is a good place to start learning to see ocean life because anchorage areas generally don’t have the overwhelming diversity of the reef. Look closely and take nothing for granted. If the water is clear you can spot things from the surface. Amazing things are right under your boat!

Pumpkin Key, Florida Keys 7/25/2016 — N25° 19.468′  W80° 18.022′ Water depth-12′

The water here was green and visibility 10 ft or less with a lot of suspended sediment. The muddy bottom was covered with Sea Grasses and Algae.  Sea Grasses are flowering vascular plants similar to what you see on land. They have developed distinct roots, stems, and leaves, and possess an internal transport system (vascular system) to distribute nutrients and fluids.

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Two species of sea grass, Turtle Grass (Thallassia testudinum) with wide flat blades, and Manatee Grass (Syringodium filiforme) with round blades.  Not hard to identify–you will know them the next time you see them.

Most marine plants, what you call Seaweeds, are algaes, simple plants that can have distinctive looking parts but less cellular diversity and no vascular system. Marine algae are much more complex than the green or brownish coating you might have had on your dirty aquarium.

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1:  Bristle Ball Brush Algae (Penicillus dumetosus)–what I used to call Mermaid’s Shaving Brush.  2:  Green Feather Algae (Caulerpa sertularioides)

As I scanned the bottom from the surface, I was able to pick out some clumps that were inconsistent with the Sea Grass bed. I dove down to investigate. These were sponges—I could identify the Rope Sponges and Fire Sponges but there were others here and there draped with sediment. Sponges fascinate me with their myriad colors and textures—fun macrophotography subjects because they so cooperative. Sponges are often confused with corals—sponges generally have openings scattered all over of different sizes while coral appears more uniform.

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A mysterious blob seen from the surface.
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Orange Rope Sponge.  It also come in several other colors.
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Fire Sponge–Fire not only because of the color.  Some sponges produce toxic substances for protection.  These can sting or cause numbness.  Usually not dangerous but irritating.
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A blue sponge wrapped around some Turtle Grass.  Most of the sponge is covered in sediment but some of the brilliant color peeks through.
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It is not easy to identify sponges.  Some of them have distinct shapes but many must be identified by looking at the spicules. Spicules are microscopic hard structures within the sponge that give it some structure.
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A sponge is made up of single cells, each of which has a whip-like structure that can produce a water current.  The cells suck water in through very small pores and filter out the food then send the water out large openings called oscula.

Another reason to look carefully at sponges is that they often harbor other forms of life. I inspected this small black sponge and found an inch long Lancer Dragonet (Paradiplogrammus bairdi). I had never seen this species of fish before. What I thought, at first, was an unusual fringe on its dorsal (top) fin, was actually a row of parasitic copepods (a small crustacean). 

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Lancer Dragonet is well camouflaged amid the sponge and sediment.  Its big eyes and pointed snout is to the left.  The greenish dorsal fin is fringed with white parasitic copepods.

There were not many fish here and the conditions were not good for photographing fish. I saw a couple of these guys near holes. I am not sure what kind of fish it is. The holes could be made by worms, shrimp, or crabs. A Barracuda also passed by me and some small Jacks.

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These small fish were always hovering around a hole and disappeared into the hole when approached.

On the way up I caught sight of a Moon Jellyfish (Aurelia aurita). The tentacles are very short but, like all jellyfish, contain stinging cells (cnidoblasts).  The cnidoblasts eject a harpoon-like structure on contact which delivers a venom. They are used for subduing prey or defense.  

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The tentacles are visible in this side view of the Moon Jellyfish
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The Moon Jelly seen from its underside.  The four-lobed structure is the gonad, the mouth is in the middle.

 

Oh–I did check out the anchor.  It was well buried.  Just forgot to take a picture of it.