Marin kayaking

There are few coastal areas along the west coast as urbanized as San Francisco Bay. But tied as our species is to land, the water of the Bay becomes the best place to experience open space. Sitting at essentially the water’s surface in a kayak, the Bay Area becomes more expansive and intimate at the same time. Water, salt and breeze are immediately present. The water is of course always in motion, so the kayaker cannot drift away in thought for too long. Constant awareness of ones’ surroundings is key.

I found a launch spot at a Marin County park on the Tiburon Peninsula and then proceeded to paddle south. The land along this part of the Bay is rocky and abrupt, leaving little easy room for development, so there is some semblance of naturalness on the peninsula. The elaborate coastal homes, some obscene in their size, are tacked onto hillsides or fill the small upland head of tiny beaches. San Francisco State’s marine science facility, converted from an old Navy installation, is located here too.

Looking across Raccoon Strait to the Golden Gate Bridge. Angel Island is to the
left and the Tiburon Peninsula is to the right.

The water enables views unattainable from land, especially along stretches of private land. With calm waters, I was able to row close to shore and observe the seaweeds on the inundated rocks, the lichens painted above the high tide line, and the trees that hang over the water.

A cruising pelican.

Pelicans passed by, some cruising at high speed just above the water surface. Still sporting a sort of dinosaurian vibe from their ancient ancestors, they are my favorite oceanic birds. I observed a dive or two during my time on the water. A diving bird descends rapidly from the sky and then hits the water in a sort of awkward splash. Some of these dives presumably end with a successful catch of fish. Every 20 minutes or so a harbor seal pokes up from under the water to peer at the visitors to his watery world, curious for a time before he dives back underwater. They probably don’t appreciate the boat traffic that criss-crosses the bay, but the smaller and quieter kayaks may be less intimidating to these animals.

North shore of Angel Island.

The Bay was reasonably calm and the main nuisance for a (non-oceanic) kayak was the motor boats that speed by quickly enough to leave wakes. Leaving the Marin mainland, I crossed Raccoon Strait (about 500 paddle strokes required) to arrive at the northern side of Angel Island. The entirety of the island is a state park. A tall island relative to its size, it has steep coastline like the Tiburon Peninsula to the north.

The island was vegetated with trees, shrubs and grasses. I found a narrow beach on the north shore, apparently inaccessible by foot, which would probably make a perfect secret picnic spot for someone arriving by small boat. I did not land on the island, but a visit ashore seems worth another trip to the island. Apparently one can camp at Angel Island too, probably an interesting camping experience in a less crowded oasis just miles away from millions of urban dwellers in all directions.

Curious harbor seal with the Richmond Bridge in the background.

The northern Hawaiian coast

Geographic regions of the Big Island. Map source

The northwestern district of Kohala and the Hamakua coast were among the final regions we visited while making a loop around the Big Island. Like Kau to the south, these areas less populated than the Kona and Hilo coasts, scattered only with small towns, farms, and impressive vistas of open space. There are a series of green valleys sculpted into the northeast-facing coast of Hamakua, largely inaccessible except by hiking.

From the North Kohala side, at the terminus of state road 270, is Pololu Valley. It appeared to have an estuary of sorts, with a sediment-laden chocolate stream that wound back into the valley. The mouth of the stream had a shallow connection to the ocean because of the buildup of large cobbles on the beach. Visible to the east were cliffs and a few offshore islets. The wind was strong here, stirring up numerous white caps out at sea. To me, the whole scene was reminiscent of portions of central California in some degree, like the rough coastal gem of the Big Sur area. 

The northwest coast of Hamakua from the overlook
above Waipio Valley. A waterfall nearly reaches
the beach.

Waipio Valley is also among this chain of coastal valleys. The valley used to be a prosperous settlement, both during Polynesian rule of the Hawaiian Islands and more recently. Hawaiians referred to it as the ‘Valley of the Kings’ (Barth 1995). A devastating tsunami in 1946 obliterated the area, and resettlement has been sparse. From Waipio Valley, there is a trail that heads northwest to the next coastal valley (Waimanu Valley) which would be a treat to backpack some day.

Down in Pololu Valley, the shore was rough with wind, waves, and a beach covered in cobbles of lava rock worn smooth by the surf. There also was a significant amount of debris – bottles, fishing buoys, decaying buckets. These items may have traveled thousands of miles to land on the shores of Hawaii. With some help from the kids, we gathered up a number of items to remove them from the beach.

Pollution is a distinctly visible reminder of humankind’s impact to our most cherished natural areas. It is particularly unwelcome on our beautiful coastlines. Yet, visibility aside, it is probably one of the lesser human impacts to the oceans. Habitat destruction, overfishing (which disrupts entire food webs), and changing climate are perhaps more pernicious threats to ocean biodiversity and function.

Pololu Valley.

A black cobble beach at Pololu Valley and the cliffs of the Hamakua coast in the distance.

Flying for hours over the vast Pacific, the immensity of the global ocean is made apparent. Individually, we are barely specks on this immense globe, so it is perhaps natural to assume that our species can have little impact on this globe. Yet evidence from every line of science points otherwise. When tsumani debris bearing living organisms arrives on the shores of Oregon from Japan (as I was able to observe firsthand a few years ago), it becomes apparent just how close supposed distant places are to each other. Our collective human impacts on our planet have become pervasive.

The kids helped gather marine debris washed ashore at Pololu Valley.

Coastal topography near Pololu Valley, from 1995 USGS topographic map, Honokane, HI.

Reference

Barth S. 1995. The Smithsonian Guides to Natural America. The Pacific. Smithsonian Books, Washington D.C.

Georgia marshes

My current research centers on climate change impacts to tidal wetlands such as salt marshes in the Pacific Northwest. I also worked in these ecosystems as a graduate student in San Diego. So, for years I have become familiar with the scientific literature on the organisms and ecology of coastal wetlands. Though I have only conducted research on the west coast, much of the literature about the plants and algae of tidal wetlands, and the ecology of these ecosystems, has come from the east and Gulf coasts of the US. So, many of the species and research sites have familiar names, but until this month I had never been in an Atlantic marsh.

Last weekend I attended the Benthic Ecology Meeting in Savannah, Georgia. There were scientific talks on fishes, coral reefs, oyster beds, and of course, salt marshes. One of the highlights of the meeting was a short underwater film festival called “Beneath the Waves”, an effort now in its fourth year. We viewed a series of short films about marine conservation, marine ecosystems and human relationships with the environment. Some of the films were produced by graduate students. Overall, the subset of films I saw at the conference were of very high quality and I highly recommend any chance to see them.



Spartina marsh with wrack.

The conference events absorbed most of my three day trip to Georgia, but after the final session of talks I snuck away for two hours down the Savannah River towards Tybee Island to see what I could of Georgia’s marshes.

The tidal wetlands of the Atlantic coast are extensive, so it was not long before I ran into waterways and wetlands. I stopped for a while at Ft. Pulaski National Monument and walked along a trail that ran parallel to the river. It wasn’t a particularly impressive marsh, but it was my first chance to see an east coast tidal wetland. There was the iconic Spartina alterniflora, a grass species that tends to form monocultures in low marsh. From my experience with the scientific literature, it is probably the most well-studied salt marsh plant in the world.

I also saw salt grass, Distichlis spicata (we have this species on the west coast as well), a species of Juncus, pickleweed, and some shrubs at the margins of the marsh. The notorious Littorina was also common. It is a dime-sized snail that has been the cause of some of the extensive marsh die-offs in Atlantic marshes. Research by Brian Silliman suggests that a simple trophic cascade can lead to marsh die-off: reductions in blue crab numbers (due to human harvest) results in an increase in the herbivorous snails and a decline in marsh plants.




Spartina alterniflora shoots with a few
 Littorina snails at the base of the plants.

 Overall the east coast salt marshes do not seem to be particularly species rich. Spartina steals most of the show. We seem to have more species and more complex assemblages in the Pacific Northwest (e.g., Jefferson 1975). However, ecological interactions among species and their environment seem to be much better understood in the Atlantic marshes due a rich tradition field experimentation, and perhaps, because those less-diverse communities are more tractable ecologically.

Atlantic salt marsh ecology has contributed to important insights into the factors that limit species distributions. For instance, salt-tolerant species (“halophytes”) tend to be excluded from fresher environments because of poor competitive ability with other species, not because they cannot tolerate fresher conditions (Crain et al. 2004). Salt-intolerant plants, on the other hand, cannot handle the level of environmental stress present in more saline marshes. Moreover, the spatial distribution of some plant species can be extended by the presence of other species because the latter essentially create more benign environmental conditions; Hacker and Bertness (1995) showed that the rush Juncus ameliorated soil salinity stress for the shrub Iva thereby allowing it to persist in lower tidal environments than might otherwise be favorable. Plant assemblages in other geographic regions – with different sets of species and different climates – may be structured differently, but the Atlantic marsh research has established useful groundwork for continued advances in tidal wetland ecology.

References

Crain et al. 2004 Ecology 85:2539
Hacker and Bertness. 1995. Ecology 76:2165
Jefferson 1975. Oregon State Univ PhD dissertation.

Oregon estuaries: some panoramas

Salmon River Estuary near Lincoln City

Netarts Bay near Tillamook