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Notice to campers staying at Coast Campground:
The Coast Trail between the Hostel and Coast Campground is closed weekdays while salvage operators attempt to remove a wrecked boat from Santa Maria Beach. The potable water sources at Coast Campground have been shut off. More »
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2012 Harbor Seal Pupping Season Closures
From March 1 through June 30, an annual closure of Drakes Estero and certain beaches of Tomales Bay is implemented to protect harbor seals during the pupping season. Please avoid disturbing seals to ensure a successful pupping season. More »
Giacomini Wetland Restoration Project: Restoration: What's the Long-Term Future of the Restored Wetlands?: Coastal Upwelling
Changes in the coastal wind patterns would not only affect temporal and spatial patterns of fog, but would potentially affect coastal upwelling. Coastal upwelling or the turnover of deep ocean waters during the summer along the Tomales Bay and Marin coast drives the amazing productivity of nearshore waters that creates a richness and diversity in aquatic life documented in few places in the world. Stronger coastal winds and temperature differentials between warmer inland and cooler coastal areas may increase the strength and intensity of coastal upwelling (Schwing and Mendelssohn 1997, Mendelssohn and Schwing 2002, Snyder et al. 2003, Barth et al. 2007). In contrast, some have predicted that stronger thermal stratification and a deepening of the thermocline could prevent cool, nutrient-rich waters from being upwelled (Roemmich and McGowan 1995), but paleoclimatic data suggests that upwelling in the California current system, as well as reduced avection in terms of ocean circulation, is positively correlated with temperature over millennial timescales (Pisias et al. 2001). While seemingly an increase in upwelling might seem on the surface to be potentially advantageous, increased upwelling could result in an increase in hypoxic events in nearshore and estuarine waters due to an over-abundance of nutrients brought up to the surface by turnover of deep, nutrient-rich ocean waters (J. Dorman, UC Berkeley, unpub. data). Researchers believe that too much upwelling may have caused the massive "dead zone" that has begun to appear with alarming regularity off the Oregon coast: Stronger, more persistent winds lead to more intense upwelling that stimulates excessive growth of phytoplankton, which sink ultimately to the bottom and decompose, sucking oxygen out of the bottom waters (Snyder 2008). These conditions may become more prevalent with climate change in the future, extending this dead zone phenomenon into California coastal waters (Snyder 2008). In addition to hypoxia, changes in upwelling may have even more direct effects on aquatic communities dependent on this phenomenon. Both phytoplankton and zooplankton densities appear to peak in abundance when wind speeds along the coast are below maximum levels–somewhere around 7 to 12 mph (Botsford et al. 2003). Higher average wind speeds could depress nearshore ocean and estuarine productivity. In addition to potential increases in intensity, climate change may also result in delayed upwelling (Schwing and Mendelssohn 1997, Mendelssohn and Schwing 2002, Snyder et al. 2003, Barth et al. 2007). Upwelling typically starts in March or April, peaks in July, and ends abruptly in October. With climate change, early season upwelling could be delayed, and the strength or intensity of late season upwelling could be increased (Schwing and Mendelssohn 1997, Mendelssohn and Schwing 2002, Snyder et al. 2003, Barth et al. 2007). These changes in temporal patterns of upwelling could result in prey populations of phytoplankton and other microscopic organisms that are highly sensitive to fluctuations in nutrients blooming later when predator populations are low, leading to so-called trophic mismatch (Durant et al. 2007). In 2005, upwelling was weak and delayed several months due to unusually warm waters and other factors: that same year, reproductive success of the planktivorous coastal bird species, Cassin's auklet (Ptychoramphus aleuticus) plummeted, presumably in response to low prey availability (Schwing et al. 2006). Not all of the effects from phenomena such as this are immediate. In 2007, escapement rates of chinook salmon (Oncorhynchus tshawytscha) crashed: an extensive evalution of potential causes by fisheries eventually led them to hypothesize that the declines occurred when the 2005 smolts entered nearshore waters—only to find low food supplies. Should upwelling be delayed in future years, seasonal declines in species such as krill (Euphausia pacifica) could have devastating effects on species such as chinook salmon and Cassin's auklet. Tomales Bay is one of the beneficiaries of the incredible productivity in nearshore waters during upwelling events. The most intensive upwelling occurs in Tomales Bay during the summer, in response to strong, often persistent northwesterly winds (Smith and Hollibaugh 1997). Upwelling elevates the concentration of particulate organic matter in the coastal waters, which is then delivered to the bay by tides and particle settling (Smith and Hollibaugh 1997). Direct inorganic nutrient delivery from coastal upwelling in the Pacific Ocean is not of major importance to Tomales Bay, but may be important indirectly by affecting nutrient dynamics or cycling within the bay (Smith and Hollibaugh 1997). While upwelling may not drive nutrient dynamics in the southern portion of the bay as strongly as it does the outer portions of the Bay, organisms from the outer Bay do move up into the uppermost reaches of the estuary, and decreased productivity in the Bay itself could lead to decreased productivity in the Giacomini Wetlands area. In addition, an increase in carbon or inorganic nutrient delivery to Tomales Bay could result in waters, which were characterized by the LMER/BRIE researchers as being relatively low in nutrients and non-eutrophic (Cole 1989; Chambers 2000; Lewis et al. 2001), becoming more prone to eutrophication and hypoxic events, all of which could affect upstream waters both directly during incoming tides and indirectly.
What's the Long-Term Future of the Restored Wetlands? restoration includes: |
Did You Know?
Harbor seals (Phoca vitulina) are present in the waters of Point Reyes year round. Every spring, approximately 7,000 harbor seals, or 20% of the mainland California breeding population, haul out on the beaches of Point Reyes. Look for them in the esteros and in Tomales Bay and Bolinas Lagoon. More...