Beaches: MBNMS

Beaches are one of the most visible and popular sanctuary habitats, representing half the intertidal habitat in Monterey Bay National Marine Sanctuary. Every year, travelers from around the world come to enjoy the natural scenery, wildlife and recreation that our beaches offer.

Beaches consist of unconsolidated material of varying sizes, most commonly sand, gravel or pebbles. Sand, for example, comes from the erosion of larger rocks both nearshore and far inland, created over long periods of time and transported to our shores by rivers, waves, winds and currents.

Beaches are constantly in flux, gaining and losing material daily and seasonally. When sand loss exceeds supply, the coast erodes. Coastal erosion poses a significant hazard in the state of California as the retreat of shorelines threatens coastal habitat and property. The Fort Ord area, for example, is experiencing some of the highest rates of erosion in the state of California.

The main process that moves sand is called “littoral drift” or “longshore drift”. See the following links from our partners for more information:

• What causes longshore drift?
• How do beaches form?
• What processes affect coastal change?

Beaches have many challenges – a few examples include issues related to water quality, coastal armoring, and trash.

• Water quality: Various agencies and citizen groups monitor the water quality of sanctuary beaches. These groups collect water samples and test for levels of coliform bacteria, which are indicators of contaminants that may cause sickness in humans. For more information visit our water quality page.
• Coastal armoring: Throughout the sanctuary, structures are installed to prevent the natural erosion of the coastline. This coastal armoring helps protect public and private property from destruction; however, it can potentially damage or alter local coastal habitats and deprive beaches of sand. Sand deprivation may cause a loss of beach and intertidal areas through a process termed “passive erosion.” The sanctuary, working with local agencies, has developed a draft management plan for this issue. Check out the link to the latest management plan.
• Trash: Refuse is dumped overboard by ships at sea, carried by rivers and storm drains from inland areas, and deposited directly on beach areas by visitors. Regardless of its origin, much of this trash ends up on beaches and can pose a threat to seabirds, marine mammals and turtles. In the sanctuary region, many people volunteer their time to pick up beach litter. Since 1985, volunteers gather every year on the third Saturday of September for the California Coastal Cleanup Day event, to collect trash on beach areas up and down the state. Join the next one!

Monitoring

Long-term Monitoring Program & Experiential Training for Students (LiMPETS)
LiMPETS is a program for middle schools, high schools and other volunteer groups; it was developed to monitor rocky intertidal, sandy beach and offshore areas of the five West Coast national marine sanctuaries: Olympic Coast, Cordell Bank, Greater Farallones, Monterey Bay and Channel Islands.

The sanctuaries and their partners monitor the abundance and distribution of major intertidal biota, sand crabs and selected offshore species to increase awareness and stewardship of these ecosystems. Various data collection procedures include transects, random quadrat counts, total organism counts, sex determination and size measurements. Data are collected so that long-term changes can be followed by interested groups working with the sanctuaries’ education staff.

Sandy beach monitoring in the West Coast marine sanctuaries focuses on the Pacific mole crab, Emerita analoga, or sand crab – a common inhabitant. Sand crabs, which filter-feed plankton from the water, are important organisms in this ecosystem. They are eaten by coastal birds and sea otters.

Sand crabs are used by humans as bait for fishing and have been used as indicators of the pesticide DDT and the neurotoxin domoic acid. The sand crab is also an intermediate host for a number of parasites, including acanthocephalans (thorny-headed worms), which affect threatened sea otters and Surf Scoters.

The Interaction of Sea Walls and Beaches: Eight Years of Field Monitoring in Monterey Bay
Active erosion is one of three potential impacts from coastal protection structures. Gary Griggs (University of California Santa Cruz) investigated this potential impact by monitoring beaches adjacent to sea walls along the central California coast, biweekly to monthly during a seven-year period. These surveys allowed Griggs to evaluate both the seasonal beach changes due to the presence of sea walls as well as any longer-term effects.

Although active erosion during winter months was documented at sea walls in this study, erosion was seasonal and temporary in nature. A comparison of summer and winter beach profiles on beaches with sea walls and on adjacent control beaches revealed no significant long-term effects or impacts from sea walls in this location during this seven-year period.

Coastal Ocean Marine Mammal & Bird Education and Research Surveys (Beach COMBERS)
Since 1997, trained volunteers have surveyed beached marine birds and mammals monthly at selected beach sections throughout the Monterey Bay area as part of the Coastal Ocean Mammal and Bird Education and Research Surveys (Beach COMBERS) program.

Beach COMBERS is a collaborative effort between Moss Landing Marine Laboratories and the sanctuary, along with other state and research institutions including California Department of Fish and Game, Marine Wildlife Veterinary Care and Research Center, and the University of California Davis. The project uses deposition of beach-cast carcasses as an index of the sanctuary’s health.

This program has been very successful – by providing data for a number of scientific papers that contribute to the conservation of sanctuary resources as well as identifying and quantifying oiled wildlife, among many other accomplishments. For example:

• The program highlighted a sharp peak (during August and September, 1997) in Common Murre, Uria aalge, deposition – in contrast to relatively stable numbers leading into and following that period. This deposition event was attributed to an increase in fishing effort and bycatch of Common Murres in fishing nets at this time
• Presence of beach-cast pinnipeds exhibited a dramatic increase in June 1998 and remained high through September 1998. This was attributed to a toxic phytoplankton bloom (i.e., a domoic acid event).
• Trends in deposition are also related to the individual species’ specific susceptibility to mortality (e.g., many young Common Murres are deposited at the end of summer) and occurrence patterns in the area. Migratory species such as Loons, Grebes, Sea Ducks and Shearwaters exhibit peaks in mortality corresponding to the time they are most abundant in the bay.
• Chronic and major oil spillage continues to be a source of mortality for marine birds in the sanctuary.

Ecological Effects of the Moss Landing Thermal Discharge
From 2002 to 2005, scientists and students at Moss Landing Marine Laboratories determined if changes in the distribution or community structure of the benthic fauna could be correlated with the thermal plume from the Moss Landing Power Plant (MLPP) outfall; and compared beach fauna to a study done in 1975.

There were no detectable significant impacts of the MLPP outfall on intertidal and shallow subtidal faunal communities. There was no significant difference in the abundance of intertidal total fauna, crustaceans or polychaetes between 1975 to 1976 and 2003 to 2005. There were, however, significantly fewer species between 2003 and 2005.