User:Pacificflower22/Palos Verdes Peninsula

Palos Verdes Reef Restoration
The reef restoration began in May 2020 which involves over 30 acres of new habitat. It is located off the coast of Palos Verdes, California, United States. This restoration consists unique designs and locations with of rock relief habitats which provide habitat for marine life. It avoids existing functioning reefs and instead uses those areas as inspiration. These habitats have been impacted by deposited or settling sediment such as sand. The main goals of the restoration project is to restore the rocky-reef territory and maximize ecosystem benefits. This has been done while taking into account engineering, economical, and physical constraints.

These habitats support about 1/4 of Marine organisms in California. Reefs are productive ecosystems. An example of an area with high fish biomass density was KOU Rock. This area had a high relief area which consistently had high biomass. Fish prefer this area because environmental conditions provide safety and adequate heat. Man-made reef structures have been modeled after the KOU Rock in effort to support and restore marine life.

Two Types of monitoring have been done for the restoration site. The first one being geophysical and oceanographic monitoring. The restoration project uses high-resolution multi-beam bathymetry data which is an instrument that uses echo-sound to measure the depth of water at different angles to create 3D maps of the ocean floor. The team used before and after pictures of the site from October 2019, the date prior to alterations, 3 different dates throughout 2020, and the final date December 2021. By 2021, the team used Edgetech 6205 MultiPhase EchoSounder, which is sends and receives audible pulses that also map the ocean's floor. Results showed net gain between 2019 and 2020. There was little net loss and fewer net gain between 2020 and 2021. Between 2019 and 2021, there were was mostly no change.

The second monitoring method was biological monitoring. The team used instruments which detected specific fish species' density and size. These instruments also showed the kelp canopy and other marine plants. By 2021, the team was able to say there was a significantly higher giant kelp density compared to the previous 3 years. There was also an increase in biotic cover, total fish density, and total fish biomass by 2021. Although kelp does function as a habitat and food source of marine species, it is not necessary for fish biodiversity. Instead, rock relief is linked to fish biodiversity.

Human caused factors such as pollution and over harvesting have altered urchin-dominated areas. Historically, pollution mitigation has been overlooked in artificial reef restoration programs. A way to mitigate issues is through assisted recovery and/or passive restoration. Experiments that have included pollution mitigation have seen a 100% success rate of achieving cleaner environments within their testing site. Heavy metals have been found in Southern California coasts. Some of these are lead, zinc, and scientists have also found DDT. The highest concentration of DDT in sediments in California have been found off the coast of Palos Verdes. 98% of sediments tested off the coast of Palos Verdes contained DDT which has contaminated 100% of two fish species. These species are the Pacific sanddab and longfin sanddab. High amounts of nutrients such as phosphorus and nitrate have also been detected in the water. These factors have caused fish tissue to decrease between the 1970s and 1980s. Due to the high concentration of DDT, commercial fishing is banned off the coast of Palos Verdes. Another factor where marine restorations fall short is in accounting for multiple important variables. Some examples are nutrients, light, wave exposure, and temporal temperatures.

Another stressor that reefs and other marine ecosystems face are human population increases. Population increased in California's coast during the 1900s. It went from 200 thousand people in Southern California in 1900 to over 17 million in 1998. Palos Verdes has been identified as a hot spot for sewage found in sediments. Invertebrates, plankton, and several species have bioaccumulated increasing amounts of chlorinated hydrocarbons as they approach Palos Verdes. When there are high levels of pollution, fish diseases such as tumors and fin erosion levels also increase.