LiMPETS Field Blog

Does Upwelling Really Raise Populations of Marine life?

October 22, 2014 Monika Krach

Authors: Francesca & Jordan

There are four seasons that we all know and love; summer, a time for swimming and tanning; fall, a beautiful season with pumpkin flavored everything; winter, the time to ski; and spring, when the winter thaws. However, many of us may not be familiar with the seasons of the ocean. These three ocean seasons are known as winter storms, upwelling, and relaxation. These seasons affect the ocean’s inhabitants much like ours affect us. One of the smaller residents of the sea that seem to be affected by these seasons is the sand crab (Emerita analoga).

Could Climbing Climate Cause a Copious Amount of Sand Crabs?

October 22, 2014 Monika Krach

Authors: Gabrielle, George & Viviana

The California coast has well established populations of sand crabs. However, sand crab populations in Oregon occur only occasionally, and seem to be replenished by those along the California coast. The Davidson current, which runs along the western coast of the United States, carries crabs from California up to Oregon. These populations thrive during a strong El Niño period, which is a period characterized by unusually warm water in the tropical Pacific and decreased upwelling along the coast of California in the summer months. Increases in water temperatures caused by El Niño have led to shifts in the distribution of many marine species northward along the California and Oregon coastlines.

Small Things Can Make Big Impacts

October 22, 2014 Monika Krach

Authors: Simone & Andrea

In general, human activities can positively and negatively influence the environment in which organisms inhabit. Every organism on this earth plays an important role in maintaining the balance of life no matter the size. Scientists may research the study of life on a small scale in order for us to better understand how small organisms can influence the environment in big ways. If in a community a small factor is harmed there might be consequences for those who heavily depend on it.

Our marine biology class participated in the LiMPETS sandy beach monitoring program on September 20th, 2014 at Ocean Beach located in San Francisco. We took 50 cores from the beach and recorded how many sand crabs were found per core. We did this so we could analyze and compare the sand crab population in the 11 years that data were collected. This is necessary in order to have a complete picture of any changes in the population.

Beyoncé’s Hit Single: Female Sand Crabs Run the World

October 22, 2014 Monika Krach

Authors: Amanda, Anne & Hannah

According to Beyonce, girls run the world, but from Bishop O’Dowd’s sandy beach monitoring data, it’s female sand crabs with eggs the run Ocean Beach. Sand crabs are important animals on California beaches because they can indicate the health of the area of the beach in which they live. Also, they are an important species in the food chain. They are the primary consumers on the beach and many other species rely on their existence.

Over the past ten years, the amount of female crabs with eggs has fluctuated greatly. The crabs had fruitful mating seasons in 2009 and 2011, as shown by the graph below. Following the pinnacle of pregnant crab abundance in 2009, Ocean Beach’s sand crab population boomed (see year 2010 in the graph). Most of these crabs were juveniles and possibly offspring of the pregnant females from the year before. This population boom may be due to climate change; recent studies have shown our planet faces challenges that may be devastating for the species that make their home, reproduce, and live in sandy beaches.

Mole Crabs and Beaches: Could We Affect Them?

October 22, 2014 Monika Krach

Authors: Halie, Jolene & Matt

Everybody loves going to a nice sandy beach. We set out to learn more about the health of beaches by analyzing the abundance of mole crabs at beaches near cities and beaches in more remote areas.

Although they are no bigger than the size of your thumb and seemingly unimportant creatures, mole crabs are very significant animals on sandy beaches. Their numbers are also indicative of the general health of the entire beach because they are in the middle of the food chain. This means that they are affected by both a scarcity in their prey or predators.

So, how do mole crab populations vary from urban beaches to remote beaches?

Students Share What They Learn Through School Blog

June 10, 2014 Monika Krach

Author: Jeff Sandler, teacher, The Berkeley School

In May 2014, the 7th grade life science class from The Berkeley School spent an entire week out in the field focusing
on some of our local communities. In addition to participating in both LiMPETS monitoring projects (sand crabs at Muir Beach and the rocky intertidal zone at Duxbury Reef in Bolinas), students and teachers spent a night camping and learning about the redwoods at Samuel P. Taylor park.

Out of the Blue

February 19, 2014 Monika Krach

A group of students from The Branson School have been monitoring key invertebrates and species of algae at Duxbury Reef in Bolinas, California for roughly 10 years. This January, we found some unexpected things. We saw an octopus, a rare sighting!

The octopus in question was an East Pacific Red Octopus, or Octopus rubescens. Like many octopuses, the Red Octopus has an amazing ability to camouflage, and is able to alter both the color and texture of its skin. We were able to experience its incredible camouflage ability first hand; the octopus first mimicked coralline algae, turning itself a reddish pink, and adopted a bumpy texture, executing a near-flawless impression of the algae. Later, after moving from the side of the pool to the floor, it turned a dark brown, in order to match the rocky substrate at the bottom of the pool.

Another interesting thing about the monitoring was the fact that no one in our group saw a single sea star. Sea stars are a common staple of intertidal life at Duxbury, so this blatant lack of sea stars was not only unusual, but also very concerning.

Experiencing the Wonders of Marine Biology

December 16, 2013 Monika Krach

We collected data about sand crabs from Ocean Beach. From the data, we came up with a question about the sand crabs, and supported it with the data we collected. We compared our findings to that of other scientific resources, like the “Pacific Mole Crab” article. We were able to see if sand crabs changed from the time the articles were made to now. When we looked at the findings, we could come up with possible causes. We gathered the information and began to put it into a blog. This process helped us become more confident in science and in writing. It’s amazing that our research is contributing to the scientific world.

Hey Folks! What’s Up With the Sand Crabs?

November 19, 2013 Monika Krach

Have you ever seen a sand crab at the beach? If not, imagine little creatures with grey shells that wiggle backwards and live underneath the sand. You may ask yourself, why should we care about some tiny sand crabs? Well the answer is simple, they are actually very important to a beach’s ecosystem, as they are the basis of the food web. By monitoring sand crabs, we can indicate the health of the entire beach.

Feeling Crabby?

November 19, 2013 Monika Krach

The question that we looked at was if the size of males, females, and females with eggs in a sand crab population on Ocean Beach change over a ten year period. Well, based off of recent monitoring at Ocean Beach on September 2013 in comparison to research at Ocean Beach on September 2003, size of males, females, and females with eggs in a sand crab population on Ocean Beach does change over a ten year period.
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