Eelgrass in Tomales Bay

Kayaking on Tomales Bay, near shore and in shallow water, we see long green strands that look a lot like seaweed, but actually, it is eelgrass. Eelgrass moved into the marine environment from land around 65 million years ago. It's actually a flowering plant, one of only two in the oceans.

Embarking on an Eelgrass Adventure, Tomales Bay.
Photo by Joseph Kinyon 2009. All rights reserved.

As the days grow longer, and the water warms, millions of pieces of pollen are released and fertilization takes place. In August these plants will then release hundreds of tiny seeds that will sink to the muddy bottom or be carried away by the current. Eelgrass beds have been the subject of interest for awhile, and scientists have some very cool findings. This plant helps to stabilize the coastal zone. Because their leaves are close together and often interwoven by the tides, they actually reduce the motion of the water. As the water slows, suspended material carried around by the tide and current, sinks to the bottom. The important supply of detritus that the eelgrass beds provide for near shore and off shore systems creates areas 10-100 times richer in animal life      compared to adjacent habitats.

In September, the leaves break away from the roots. Some float away, carried by currents; others fall to the bottom where a large percentage of the leaves decompose. Microscopic organisms begin to break down the leaves into smaller particles, and these become surrounded by bacteria and fungi. Bacteria and fungi are consumed by filter feeders such as clams and scallops. Deposit feeders (such as sea urchins) and sediment feeders (worms and snails) also join in to feast. The adult and larval forms of these invertebrates become food for larger life forms such as fish. The closely packed leaves provide a safe haven for young fish to try to avoid predation, the dense jungle of leaves often deters larger fish from going in too far. Thus the continuous cycle that eelgrass plays such a vital role is illuminated.

Eelgrass is difficult to eat for many birds because it is extremely fibrous. However, Brandts Geese rely on eelgrass to survive their 3000 mile migration. They have a specialized crop to ease digestion. Surf Scoters and Scaups swim down and clip off pieces of eelgrass in order to eat the herring eggs that are developing on the blades.

Dendronotus Iris Nudibranch. Photo by Joseph Kinyon 2009.
All rights reserved.

Waterfowl are often easy to spot, but what they are looking for in the eelgrass often eludes us, unless we look carefully. Hiding within the jungle of blades one can find: herring eggs, nudibranch (sea slugs) and their eggs, copepods & isopods (small crustaceans), polychates (marine worms), clams, bryozoans, and varying forms of bacteria and fungus. At least 20 species of commercially valuable fish rely on eelgrass for food and habitat at some point in their lives. Searching for food in the rich, muddy areas surrounding the beds we often see leopard shark, bat rays, and other large predatory fish.

As we learn more and more about eelgrass, we also learn that eelgrass is helping to mitigate the impacts of humans on our waterways. Eelgrass is crucial to maintaining water quality. 1 acre of eelgrass absorbs 6.4 pounds of nutrients. This is equal to the effluent from 490 people for 1 year. Eelgrass plays a significant role in moderating the effects of increased carbon dioxide on our planet. 1 acre of eelgrass removes 7400 pounds of carbon. This is equal to the carbon dioxide emitted from a car traveling 3860 miles. Eelgrass beds are very difficult to restore once they have been destroyed (by pollutants, boat propellers and anchors, dredging and development). Less than 10% of restoration attempts are successful after 10 years.

Splendor in the Eelgrass, Taylor's Sea Hare. Photo by Joseph Kinyon 2009.
All rights reserved.

Next time you are out on the water, tread lightly in eelgrass zones and be sure to take a closer look at the eelgrass beneath your boat. For a special treat, check out the eelgrass beds after dark. Bring a headlight and be prepared to get wowed by all of the creatures.

Want more: Check out Joseph Kinyon’s article Splendor in the Grass, on Bay pipefish, an eelgrass resident with some extraordinary adaptations for its environment.
Photos provided by Joseph Kinyon. All rights reserved. To contact Joseph or to see more of his photos, Find his "palustrine" Flickr  page.

Tidepooling at Duxbury Reef, Bolinas, CA

Kayaking on Tomales Bay allows us to see some critters often found in tidepools, however, walking out on Duxbury Reef and checking out nooks and crannies allows for some awesome discoveries. A group of sixth graders from Marin joined us at the reef for some exploration and we saw some neat creatures.

We found rose anemones, sea urchins, giant anemones, aggregate anemones, starfish including purple and orange ochre stars, chitons, limpets, crabs, and the coolest find, an octopus.

A quick moment on tides. The water in the ocean is constantly moving, caused by the forces of gravity from the moon and the sun. High tide is when the sun and the moon are lined up with the earth, causing the water to pull away from the earth. Low tide is when your area is not lined up with the moon. Low tides not around the full moon or new moon are usually best for exploring. Consult your local tide logs to determine when you should go. Most places are best when the tide is between 1 and negative 1. If the tide is less than negative 1, get out there for a rare preview into the world of creatures rarely visible to humans without a snorkel. Remember to respect the creatures living there, moving them or trying to free them from rocks can be quite detrimental to them.

We went out on a day with a -0.6ft tide at 9:30am. Ideally you want to be out exploring before the lowest point of the tide. Be careful when in tidepools, never put your back to the ocean, waves can sneak up and potentially knock you over and they tend to be very slippery areas. Also be aware that channels will fill with water that may block your way back, be sure not to get stuck out on a reef with no way back to dry land. You will find different creatures dependent on which tidal zone you are looking in and hte height of the tide.

Biking in Point Reyes National Seashore

Lots of folks go hiking in Point Reyes, although great bike trails exist. Just outside Point Reyes Station, we went for a mellow bike ride on the Bear Valley Trail, located at the Bear Valley Visitor Center. I have lived in this area for five years now, and told countless people to go check out Arch Rock. I have heard it is a great spot to go, that it is lovely, a nice beautiful hike and yada yada. For whatever reason, I have never gone!! So when a friend came to visit last week, it was a perfect opportunity to play tourist in my own town and check out some places I have never been, and Arch Rock was at the top of my list. I have hiked on the Bear Valley trail, but never out to the arch. This trail is perfect because it combines a bike ride, a hike, and a beach walk. You start in a forest, go to chaparral and end up at the ocean. There is a creek you walk along for awhile and cross to get to a viewing spot of the arch, anyway, great combination; this trail really shows off Point Reyes National Seashore.

Starting from the parking lot it is about 1.5 miles to Divide Meadow, a great spot for a picnic, snack or throwing a Frisbee if you are walking. There are a couple of trails that diverge off of this trail, but bikes aren’t allowed. There are bathrooms at the meadow, which is a nice feature, although I always forget they are there for some reason. On bikes it took us less than ten minutes to get to the meadow, so we weren’t ready to stop yet. Anyway, another 1.5 miles gets you to the trail junction. At this point you have to lock up your bike, racks are provided, and continue on foot. I was bummed at first to get off the bike, but the wildflowers were going crazy and there was a lot of great stuff to take pictures of, and on a bike I would have blown right by and never even noticed. It is about a mile from the bike racks out to the ocean. The trail stops at a bluff at which point you will notice a switchback down into the creek. This part of the trail is a little sketchy for folks that aren’t as stable on their feet.

We got there at a high tide, oops, should have planned that better. So beach walking was limited, but we could still wander around and see the waves crashing through the arch.