#1044 - 1052 - Green Algae, including Dead Man's Fingers and Velvet Golfballs
#1044 - Bryopsis sp. - Sea Fern Alga
Feathery green alga, most infamous for growing out of control in marine aquaria. It’s not usually very common in the wild, but it thrives on changing temperatures, high nutrient levels in the water, and is too poisonous for most things to eat. And it can grow from tiny fragments.
Found in a rockpool at Halls Head.
#1045 - Caulerpa cactoides
The first of several of these brilliant green seaweeds native to Perth’s shores. Caulerpa plants consist of a single, multinucleate cell - some plants can be 3 meters long.
Some Caulerpa species are edible (especially Caulerpa lentillifera and C. racemosa), and have a peppery taste. This “green caviar”, or “sea grapes” may be eaten fresh or covered in sugar. These species are raised in Catanduanes and Cebu, for domestic consumption in the Philippines and export to Japan.
HOWEVER - other species, such as the highly invasive C. taxifolia, are poisonous. This has enabled them to invade the Mediterranean, Australia, and for a while Southern California, since the local herbivores can’t eat the stuff. They’re also used as nitrite scrubbers in marine aquaria, which might be how they ended up in the Med, etc. Nine species are banned in California, for that reason.
Falcon, Perth.
#1046 - Caulerpa flexilis
Photo by @gemfyre. Seen at the edge of the limestone overhangs at Point Peron, while we were snorkelling.
#1047 - Caulerpa longifolia
In a deep rockpool in Falcon.
#1048 - Caulerpa racemosa var. cylindracea
Native to the SW, invasive in South Australia. Seen in rockpools at Halls Head.
#1049 - Caulerpa sedoides forma geminata
Young Caulerpa fronds, attached to the thalli that give the genus of “crawling stems” their name, via the Ancient Greek.
Found in the very shallowest parts of the rock platforms at Halls Head, and elsewhere.
#1050 - Codium mammilosum - Velvet Golf Ball
Another single-celled green macroalgae, consisting of hundreds of tubes whose swollen ends form the surface of these spherical seaweeds.
Falcon, Perth. The day I found these ones most of the beach was covered in seaweed, and every few steps I’d find one I hadn’t seen before. I pity the early marine biologists, who had to study and preserve seaweeds based only on what washed up, and what they could bring to the surface with rakes.
#1051 - Codium sp. - Dead Man’s Fingers
I don’t know which species of Codium, since there are several with a similar long, branching form. Common names for these ones include green sea fingers, dead man’s fingers, felty fingers, forked felt-alga, stag seaweed,sponge seaweed,green sponge,green fleece, and oyster thief. As with the velvet golf ball, it’s all one multinucleate cell, up to a meter long.
Falcon, Perth
#1052 - Halimeda sp. - Cactus Algae
A calcareous green seaweed resembling a tiny Prickly Pear, hence the common name, and for that matter the scientific binomial of such species as H. opuntia. As with the rest of the Bryopsidales I’ve been covering, it’s all a single cell. In fact, entire Halimeda meadows can consist of one cell, each ‘plant’ connected by threads running through the sand or calcareous gravel they’re growing in.
In the Great Barrier Reef, large deposits of Halimeda plates may accumulate, and accumulate rapidly - they’re the primary reef-building organism in tropical seas, vastly outproducing the stony corals. One bed some 2,000 km2 in extent, and up to 15m deep, was almost entirely algal deposits. A patch of Halimeda the size of an average living room would produce 50kg of aragonite a year, and the colonies can double in mass every 15 days. Naturally, this makes them useful in marine aquaria, for sucking nutrients out of the water.
As well as the aragonite content to discourage herbivores, Halimeda synthesise the noxious diterpenoid compounds halimedatrial and halimedatetraacetate. Further, they can protect themselves from chloroplast-stealing sacoglossan lettuce slugs, by migrating the chloroplasts of the green tissue (normally clustered near the surface of the thallus) deeper into the armoured interior at night.
Fossil deposits can be quite distinctive.
Falcon, Perth, growing under the lip of a limestone overhang at low tide.
Feathery green alga, most infamous for growing out of control in marine aquaria. It’s not usually very common in the wild, but it thrives on changing temperatures, high nutrient levels in the water, and is too poisonous for most things to eat. And it can grow from tiny fragments.
Found in a rockpool at Halls Head.
#1045 - Caulerpa cactoides
The first of several of these brilliant green seaweeds native to Perth’s shores. Caulerpa plants consist of a single, multinucleate cell - some plants can be 3 meters long.
Some Caulerpa species are edible (especially Caulerpa lentillifera and C. racemosa), and have a peppery taste. This “green caviar”, or “sea grapes” may be eaten fresh or covered in sugar. These species are raised in Catanduanes and Cebu, for domestic consumption in the Philippines and export to Japan.
HOWEVER - other species, such as the highly invasive C. taxifolia, are poisonous. This has enabled them to invade the Mediterranean, Australia, and for a while Southern California, since the local herbivores can’t eat the stuff. They’re also used as nitrite scrubbers in marine aquaria, which might be how they ended up in the Med, etc. Nine species are banned in California, for that reason.
Falcon, Perth.
#1046 - Caulerpa flexilis
Photo by @gemfyre. Seen at the edge of the limestone overhangs at Point Peron, while we were snorkelling.
#1047 - Caulerpa longifolia
In a deep rockpool in Falcon.
#1048 - Caulerpa racemosa var. cylindracea
Native to the SW, invasive in South Australia. Seen in rockpools at Halls Head.
#1049 - Caulerpa sedoides forma geminata
Young Caulerpa fronds, attached to the thalli that give the genus of “crawling stems” their name, via the Ancient Greek.
Found in the very shallowest parts of the rock platforms at Halls Head, and elsewhere.
#1050 - Codium mammilosum - Velvet Golf Ball
Another single-celled green macroalgae, consisting of hundreds of tubes whose swollen ends form the surface of these spherical seaweeds.
Falcon, Perth. The day I found these ones most of the beach was covered in seaweed, and every few steps I’d find one I hadn’t seen before. I pity the early marine biologists, who had to study and preserve seaweeds based only on what washed up, and what they could bring to the surface with rakes.
#1051 - Codium sp. - Dead Man’s Fingers
I don’t know which species of Codium, since there are several with a similar long, branching form. Common names for these ones include green sea fingers, dead man’s fingers, felty fingers, forked felt-alga, stag seaweed,sponge seaweed,green sponge,green fleece, and oyster thief. As with the velvet golf ball, it’s all one multinucleate cell, up to a meter long.
Falcon, Perth
#1052 - Halimeda sp. - Cactus Algae
A calcareous green seaweed resembling a tiny Prickly Pear, hence the common name, and for that matter the scientific binomial of such species as H. opuntia. As with the rest of the Bryopsidales I’ve been covering, it’s all a single cell. In fact, entire Halimeda meadows can consist of one cell, each ‘plant’ connected by threads running through the sand or calcareous gravel they’re growing in.
In the Great Barrier Reef, large deposits of Halimeda plates may accumulate, and accumulate rapidly - they’re the primary reef-building organism in tropical seas, vastly outproducing the stony corals. One bed some 2,000 km2 in extent, and up to 15m deep, was almost entirely algal deposits. A patch of Halimeda the size of an average living room would produce 50kg of aragonite a year, and the colonies can double in mass every 15 days. Naturally, this makes them useful in marine aquaria, for sucking nutrients out of the water.
As well as the aragonite content to discourage herbivores, Halimeda synthesise the noxious diterpenoid compounds halimedatrial and halimedatetraacetate. Further, they can protect themselves from chloroplast-stealing sacoglossan lettuce slugs, by migrating the chloroplasts of the green tissue (normally clustered near the surface of the thallus) deeper into the armoured interior at night.
Fossil deposits can be quite distinctive.
Falcon, Perth, growing under the lip of a limestone overhang at low tide.