Sandy Beaches and Dunes

What comes to mind when you hear the phrase, “Sands of time?”

An hour glass?… video game?… song title?… book?…

Those would have been my thoughts, too.
Until now.
My most recent Oregon Master Naturalist class put the notion of sands of time into a much different perspective. David Lonsdale gave this phrase new meaning as he lead a full day of activities and learning discoveries at the Hatfield Marine Science Center, and nearby South Beach State Park in Newport, Oregon.
 

The photo-circles above clearly show “sand.” We find it on beaches everywhere and easily recognize it as tiny-tiny particles of pulverized rock and mineral. We’re happy when we get to the beach, and promptly begin to enjoy sand-related activities; not really giving sand much of a second thought. But a healthy helping of  “second thought” is what sand deserves. It is fascinating. And so are the physical and biological systems that rely on sand.

20140314-classroom_presentations

 Here is where a new spin on the   sands of time  gets underway…

With two questions:

– What is sand?

– Where does sand come from?

The sand on Oregon beaches formed as rock was broken down through weathering and erosion into sedimentary particles between 0.0625 (1/16) mm and 2mm in diameter.This process occurred during the late Pleistocene(11,700BP) and Mid-Holocene (6,000BP) in rivers that washed these particles to the ocean where they have been carried by tides and winds along the coastline to form sandy beaches and dunes. In this sense, we walk along the sands of time each time we visit the beach. These old sands, or relic sands, are a mix from four source sites:

  1. Columbia River (Igneous- Mineralogy: Hypersthene and Augite)
  2. Coast Range (Ingneous- Mineralogy: Augite and Hornblend)
  3. Umpqua River (Igneous and Metamorphic- Mineralogy: Augite, Hornblend, Hypersthene, and Garnet)
  4. Klamath Mountains of Southern Oregon and Northern California (Igneous and Metamorphic- Mineralogy: Augite and Garnet) (Lonsdale)

Time in the Hatfield Marine Science lab gave us the opportunity to examine sand structure with microscopes. The mineral blend and roundness/sphericity provided clues to the age of the sands of time. Older sands were more rounded; more recent sand particles were more angular.

Why is sand so important?

I think it is safe to say that sand is the foundation  for life in the sandy beach-dune ecoregion. Without sand… organisms from microscopic to the very largest  would perish.  The food web begins with the microscopic organisms that live between the grains of sand. When we take walks along intertidal zones, we are literally walking on the backs of the meiofauna community of organisms that reside there… about a million of these microbial creatures can be found in just a square meter of beach. If we consider sandy beaches account for about 72% of Oregon’s coastline… that’s a lot of inhabitants!

The Hatfield Science Lab provided an opportunity to view  some of the microscopic  between-sand-particle dwellers.I did not have the ability to take photographs of the meiofauna we viewed during our microscope studies. However, the above video provides an informative and entertaining look at the organisms that live between the grains of sand. Watch to view living examples of meiofauna and to learn more about them. It’s well worth the time!

David also set up a display of preserved specimens to give us some ideas  about what to look for once we were out on the beach and in the dunes. Click to view as a slideshow and the labels will be easier to read:

Newport Littoral Cell- South Beach State Park- Newport, Oregon

After lunch, we proceeded to South Beach State Park.  The sandy beaches and dunes we explored are located in the Newport Cell, a littoral cell that is twenty-seven miles long; between Yaquina Head and Cape Perpetua. Sand movement in the area where we worked is impacted by beach stabilization projects and the Yaquina Bay jetty system. Shoreline topography is dramatically, and largely irreversibly, affected by these anthropogenic impacts on the once dynamic seasonal and landform-related sand dune movements driven by wind and tide patterns. Of the two human-made disturbances, beach stabilization is the most profound. The introduction of European Beach grass has been so successful in preventing natural sand shifting that Oregon’s dunes are actually disappearing. Some experts predict much of our state’s wild dune system will be gone within the next 50-100 years. “European Beach grass on the foredunes permanently (minimizes) sand movement, thereby trapping all windblown sand at the foredune and thus starving inland areas from the formation of the larger dune features,.”(Lonsdale)

In the next sections of this entry, I will use the “Field Trip Workbook and Field Diary” as a guide. David gave us this tool to record our Naturalist activities and observations. Unfortunately- wind, rain, and time constraints of the day prevented us from the benefit of using it to its fullest potential on site.

Dune Observations-

After breaking into teams, we drove to South Beach. Prior to beach entry we reviewed Oregon Parks Department signage. A trek through dunes allowed an initial observation opportunity to identify dune features. A second dune walk later in the day provided another occasion to make observations.This set of photos is a record of my observations during both walking tours of dune areas on March 15, 2015. Notes are written in the caption area for each photograph. Clicking on a photo to view as a slideshow makes reading of notations easier. I have attempted to label correctly, however, if errors have been made- I would appreciate feedback in the comments area below this post. Then I can make the corrections.  Thank you in advance 🙂

Transect to Assess Distribution and Abundance of South Beach Macrofauna

Step 1- Abiotic Profile

Recently, I noticed that NASA lists the “Vital Signs of the Planet” on its Global Climate Change website (link is at the bottom of my blog). Over time, this abiotic data will assist scientists to educate the public on the patterns that confirm global change. As a Master Naturalist, knowing what data to collect and how to collect it is a timely and valuable skill.  The next set of photographs record the collection of data.

Site Location: South Beach State Park, South Jetty (Newport, Oregon)

Date: March 15, 2014       Time Profile Developed: 1300           Profile Location: Surf zone- Sandy Beach

Weather:  Mist                     % Cloud Cover:  100%                             Air Temperature:  54 F;  17 C

Type of Substrate:  100% fine sand; some debris                           Tidal Information:  12:18 was high tide

 Sea Conditions:  Small surf with larger swells

Dissolved O2 Concentration (ppm): 7

pH:  7.5

Salinity (0/00):  30.9                       Water Temperature:  16.7 C

Wind Speed:  Steady Wind   15mph   12-16 knots

Step 2:  Transect Teams Assess Distribution and Abundance of macrofauna

At the surf zone, nets were used to sweep along the bottom back and forth digging the rim shallowly into the sand. Then we examined for biota by dumping the catch into a several inches of water in a bucket.

David modeled the process of setting up our data collection sites along lines of transect. Starting at the swash zone we measured 100 feet eastward toward the last high tide strand line. Zero feet was station one where the first set of four holes were dug and assessed for biota. This process continued every 10 feet up the transect line.

Macroflora (and one insect) Observed during Dunes Walking Tour

Sands of Time – Tides of Change

The experiences of this field trip …anchored in the sands of time… those of distant and present times … impacted my activities on this particular day. What will happen in these dunes, and others along the Oregon coastline, is waiting to be told as dynamic earth events and  anthropogenic activities merge.Learning to pay attention, to use data wisely, and to make informed decisions in how we choose to manage- or not manage- natural resources seems more important now than ever.

Resources:
“Between the Grains;”http://meiochile.matthewlee.org/?p=1240
Weidmann, AM.1984.The Ecology of Pacific Northwest Sand Dunes: A Community Profile. U.S. Fish and Wildlife Service: FWS/OBS-84/04
USDA Forest Service; http://www.fs.usda.gov/detailfull/siuslaw/learning/nature-science/?cid=fsbdev7_007155&width=full
Pojar and MacKinnon; Plants of the Pacific Northwest Coast

2 comments

  1. A lot of information here — will keep an eye out for tree islands, depression plains, and mole crabs!
    Interesting that garnet comprises such an important part of the sand. Here it is, all ground to bits, long before the making of the Anglo-Saxon jewelry that the Heritage Trust blog has posted about recently. Talk about “the sands of time”…

    Like

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