Palos Verdes Peninsula: Difference between revisions

▲=== Palos Verdes Reef Restoration ===

▲The reef restoration began in May 2020 involving over {{convert|30| acres}} of new habitat. Located off the coast, this restoration consists unique designs and locations with of rock relief habitats which provide habitat for marine life.<ref name=":0">Williams JP, Williams CM, Pondella DJII and Scholz ZM (2022) Rebirth of a reef: As-built description and rapid returns from the Palos Verdes Reef Restoration Project. ''Front. Mar. Sci.'' 9:1010303. doi: 10.3389/fmars.2022.1010303</ref>. It avoids existing functioning reefs and instead uses those areas as inspiration<ref name=":0" /> 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.<ref name=":0" />l

▲Reefs are productive ecosystems.<ref name=":1">Earp, Hannah S., et al. “A Quantitative Synthesis of Approaches, Biases, Successes, and Failures in Marine Forest Restoration, with Considerations for Future Work.” ''Aquatic Conservation: Marine and Freshwater Ecosystems'', vol. 32, no. 11, 2022, pp. 1717–31, <nowiki>https://doi.org/10.1002/aqc.3880</nowiki>.</ref> 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<ref name=":0" /> 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<ref name=":0" />, which is sends and receives audible pulses that also map the ocean's floor. Results showed net gain between 2019 and 2020<ref name=":0" />. There was little net loss and fewer net gain between 2020 and 2021. Between 2019 and 2021, there were was mostly no change<ref name=":0" />.

▲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<ref name=":0" />. There was also an increase in biotic cover, total fish density, and total fish biomass by 2021<ref name=":0" />. 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<ref>Stephens, John S., et al. “Factors Affecting Fish Diversity on a Temperate Reef: The Fish Assemblage of Palos Verdes Point, 1974-1981.” ''Environmental Biology of Fishes'', vol. 11, no. 4, 1984, pp. 259–75, <nowiki>https://doi.org/10.1007/BF00001373</nowiki>.</ref>.

▲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<ref name=":1" />. 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<ref>Gianni, Fabrizio, et al. “Conservation and Restoration of Marine Forests in the Mediterranean Sea and the Potential Role of Marine Protected Areas.” ''Advances in Oceanography & Limnology'', vol. 4, no. 2, 2013, pp. 83–101, <nowiki>https://doi.org/10.4081/aiol.2013.5338</nowiki>.</ref>. Heavy metals have been found in Southern California coasts. Some of these are lead, zinc, and scientists have also found DDT. The highest [[Chemical dumps in ocean off Southern California|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<ref name=":2">SCHIFF, KENNETH C., et al. “Southern California.” ''Marine Pollution Bulletin'', vol. 41, 2000, pp. 76–93.https://ftp.sccwrp.org/pub/download/DOCUMENTS/JournalArticles/333_scb.pdf.</ref>. High amounts of nutrients such as phosphorus and nitrate have also been detected in the water<ref name=":2" />. These factors have caused fish tissue to decrease between the 1970s and 1980s<ref name=":2" />. 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<ref name=":1" />.

▲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<ref name=":2" />. 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<ref name=":2" />. When there are high levels of pollution, fish diseases such as tumors and fin erosion levels also increase<ref name=":2" />.