Saturday, September 13, 2014

August 25th-August 31st

August 25th-August 31st

Daily Low Tides

Monday, August 25th
-0.2' @ 7:20 AM
1.3' @ 7:29 PM

Tuesday, August 26th
0 @ 7:51 AM

Wednesday, August 27th
0.2' @ 8:19 AM

Thursday, August 28th
0.5' @ 8:47 AM

Friday, August 29th
0.8' @ 9:15 AM

Saturday, August 30th
1.2' @ 9:45 AM

Sunday, August 31st
1.7' @ 10:22 AM

This week saw lots of sea gooseberries (a type of ctenophore, or comb jelly) and jellyfish washed up on the beach, although no more purple sailors. We also spotted a rock louse, an arthropod that looks a bit like a cockroach.

A rock louse climbing over barnacles. Photo by Katie Corliss.

Shifting our gaze upwards: the last of the tufted puffins are still hanging around, spotted mainly on the north and west sides of the Rock. As the nesting season winds down, these birds will begin heading out to open sea, where they spend their winters. They'll be back in March.

Puffins aren't the only birds winding down their nesting season. HRAP interpreters have been spotting more and more cormorants resting and sunning themselves on the rock. With most of their chicks fledged, their job is done for the summer. Well done everybody!

Creature Highlights

Staff interpreter Katie Corliss has provided us with some great sand dollar shots this week. We don't often see living sand dollars unless we're at an aquarium or SCUBA diving. These echinoderms-- the group that contains sea stars, urchins, and cucumbers-- are more likely to be found underwater than in the intertidal zone which we humans are able to access at low tide. Beachcombers are familiar with their "tests," or internal shells, because they tend to wash up on the shore. But what are these animals like when they're alive?

 The "furry" underside of a living sand dollar. Photo by Katie Corliss

When alive, the sand dollars common off the Oregon Coast (Dendraster eccentricus, or the Eccentric sand dollar) are purple and furry looking. This '"fur" is actually thousands of tiny tube feet which help the animal move, feed, and breathe. Special flattened tube feet on the "petaloids" (the five loops on the upper surface of the sand dollar that look like flower petals) exchange waste for oxygen. Incidentally, these five petaloids are an example of the five-part radial symmetry shared by all echinoderms. (Think of the five arms of a typical sea star.)

Sand dollar tests are a familiar site to beachcombers. The five loops are the "petaloids," which function as the site of gas exchange in the living animal. Photo by Katie Corliss.

Sand dollars also use their tube feet to move food particles from the sand or water along the grooves on the underside of their body and into their mouths. If occupying a rough, energetic environment with lots of wave action, these animals will bury themselves under the sand, but when conditions are calm they will just out from the sand at an angle. In some species, young sand dollars ingest dense particles of sand or rock to serve as ballast, keeping them anchored to the seafloor.
Birds

Tufted Puffin (Fratercula cirrhata)
Common Murre (Uria aalge)
Black Oystercatcher (Haematopus bachmani)
Western Gull (Larus occidentalis)
Black Turnstones (Arenaria melanocephala)

Intertidal

Ochre star (Pisaster ochraceus)
Shaggy mouse nudibranch (Aeolid papillosa)
Opalescent nudibranch (Hermissenda crassicornis)
Lion's mane jelly (Cyanea capillata)
Red rock crab (Cancer productus)
Dungeness crab (Cancer magister)
Striped surfperch (Embiotica lateralis)
Cabezon
Starry flounder (Platichthys stellatus)
Leather chiton (Katherina tunicata)
Pacific sea nettle (Chrysaora fuscescens)
Ctenophores
Bryozoans
Purple sea urchins (Strongylocentrotus purpuratus)
Rock louse (Ligia pallasii)
Porcelain crab (Petrolisthes eriomerus)

References

Brusca, R.C. and Brusca, G.J. (eds.) Invertebrates. 2nd ed. Sunderland, MA: Sinauer Associates, Inc. 2003.

Sept, J. D. The Beachcomber's Guide to Seashore Life of California. Revised edition. Madeira Park, B.C.: Harbor Publishing. 2002. 





Friday, September 12, 2014

August 18th-August 24th

August 18th- August 24th

Daily Low Tides

Monday, August 18th
2.4' @ 1:18 PM

Tuesday, August 19th
2.7' @ 2:27 PM

Wednesday, August 20th
2.7' @ 3:33 PM

Thursday, August 21st
2.5' @ 4:32 PM

Friday, August 22nd
-0.2' @ 5:32 AM

Saturday, August 23rd
-0.3' @ 6:12 AM
 1.9' @ 6:09 PM

Sunday, August 24th
-0.3' @ 6:48 AM
1.6' @ 6:50 PM

Notes from the week

First, an addition to our notes from a couple weeks back. Remember the mighty fighting anemones from our August 4th-10th post? In that post, we linked to documentary footage of anemones defending their territory by extending their stinging, club-shaped acrorhagi. This week, thanks to staff interpreter Alanna Kieffer, we have video of our own Haystack Rock anemones doing the same thing.

video

  Green sea anemones "fighting."

Also, some good news from the Rock this week: HRAP interpreters spotted lots of juvenile and adult ochre stars (one of the species that has been hit hard by Sea Star Wasting Disease-- see previous Nature Blog posts.) Let's hope the population can recover from the devastating, mysterious illness that wiped out so many of our sea stars this year.


Creature Highlights

A question Haystack Rock interpreters got a lot this week was, "What are those tube things?" 

These sand-covered parchment-like tubes, roughly the size and shape of a paper finger trap, have been showing up in the tidepools for several weeks.

These tubes are actually the empty houses of a segmented worm know by several names, including cellophane worm, glassy tube worm, and jointed tube worm. The tubes are produced by the worms themselves and are made of chiton, a protein that also forms the exoskeletons of crabs and insects. When occupied by a living worm, long palps, each equipped with an eye spot, extend from the anterior portion of the worm (the head, more or less) and out of the opening of the tube. They use strings of mucus to capture passing food particles, which they wind up in a ball before eating.

Cellophane worms make their own houses because shelter can be hard to come by in the intertidal-- a fact that also explains this little hermit crab having a "make it work" moment:

A hermit crab in a barnacle shell.

Birds

Black oystercatcher (Haematopus bachmani)
Western gulls (Larus occidentalis)
Harlequin ducks (Histrionicus histrionicus)
Pigeon Guillemot (Cepphus columba)

Intertidal

Stiff-footed sea cucumber (Eupentacta quinquesemita)
Dungeness crab (Cancer magister)
Opalescent nudibrach (Hermissenda crassicornis)
Shaggy mouse nudibranch (Aeolid papillosa)
Six-ray star (Leptasterias hexactis)
Keyhole limpets
Rufus Tipped nudibranch (Acanthodoris nanaimoensis)
Spiny lithode crab (Acantholithodes hispidus)
Decorator crab

References

Nishi, E., and Arai, Y. 1996. Chaetopterid Polychaetes from Okinawa Island, Japan, with Notes on the Feeding Behaviour of Spiochaetopterus costarum costarum. Publications of the Seto Marine Biological Laboratory. 37 (1-2) pp 51-61.

http://www.wallawalla.edu/academics/departments/biology/rosario/inverts/Echinodermata/Class%20Holothuroidea/Eupentacta_quinquesemita.html Accessed 9/13/14

http://www.wallawalla.edu/academics/departments/biology/rosario/inverts/Echinodermata/Class%20Asteroidea/Leptasterias_hexactis.html

http://eol.org/pages/343031/overview