National science foundation (NSF) in 1980 established The Long Term Ecological Research (LTER) Network to conduct research ecological issues that can last decades and span huge geographical areas.
The Network brings together a multi-disciplinary group of more than 2000 scientists and graduate students. The 26 LTER sites encompass diverse ecosystems in the continental United States, Alaska, Antarctica and islands in the Caribbean and the Pacific.
LTER is an international best organized and most successful groups conducting research in ecology. The aim of the LTER is to pursue a long-term research on based on long-term data and information which is necessary for truly understanding environmental phenomena.
27717756096026 Sites of LTER:
Andrews Forest LTER (AND)
Arctic LTER (ARC)
Baltimore Ecosystem Study (BES)
Bonanza Creek LTER (BNZ)
California Current Ecosystem LTER (CCE)
Cedar Creek LTER (CDR)
Central Arizona – Phoenix LTER (CAP)
Coweeta LTER (CWT)
Florida Coastal Everglades LTER (FCE)
Georgia Coastal Ecosystems LTER (GCE)
Harvard Forest LTER (HFR)
Hubbard Brook LTER (HBR)
Jornada Basin LTER (JRN)
Kellogg Biological Station LTER (KBS)
Konza Prairie LTER (KNZ)
LTER Network Office (LNO)
Luquillo LTER (LUQ)
McMurdo Dry Valleys LTER (MCM)
Moorea Coral Reef LTER (MCR)
Niwot Ridge LTER (NWT)
North Temperate Lakes LTER (NTL)
Palmer Antarctica LTER (PAL)
Plum Island Ecosystems LTER (PIE)
Santa Barbara Coastal LTER (SBC)
Sevilleta LTER (SEV)
Shortgrass Steppe (SGS)
Virginia Coast Reserve LTER (VCR)
Among 26 LTER sites The California Current Ecosystem (CCE) would be described here.
3714750258445California Current Ecosystem (CCE):
CCE LTERs is located off the southern coast of California, extending from San Diego north to San Luis Obispo and westward over 500 km.
Geographical location is
Types of Ecosystem:
California Current system is a coastal upwelling biome and it is coastal pelagic ecosystem.CCE includes eastern current (California current) of North pacific gyre. This currents circulate water around the North Pacific Ocean. In this current, wind acts on sea surface and it facilitates the upward movement of nutrient rich deepwater so that surface dwellers can take this nutrient. This process is known as coastal upwelling. Upwelling ecosystems are most productive ecosystems. The CCE sustains active fisheries for a variety of marine invertebrates ,finfish and aquatic animals, modulates hydrologic cycle ,weather patterns of most of the west coast of United States, and plays a vital role in the economy of myriad coastal communities.
Area of interest: why this site has chosen
It is an ideal location of LTER because it has 5 decades of climate context provided by the calCOFI (California Cooperative Oceanic Fisheries Investigations). The location of this site is in a bigeographic boundary where climate change is very rapid. Within this small geographic area there is a pronounced spatial gradient and its anoxic basins provide a unique connection to paleoceanographic studies; and the extant 4-D physical ocean circulation model of the region will permit rapid advances in the development of coupled bio-physical models of ecosystem transitions. LTER network can compare the coastal pelagic upwelling ecosystem with other biomes in respect to primary production pattern and control, of inorganic inputs and movements of nutrients patterns, Spatial and temporal distribution of populations selected to represent trophic structures, , and disturbances frequency and pattern.
Types of researches have been done and going on:
California Cooperative Oceanic Fisheries Investigations (CalCOFI) has studied the CCE LTER site over 60 years. Scientists have observed changes in the CCE that happen over a variety of time scales. The changes include the Pacific Decadal Oscillation, and El Niños which results in long term ocean warming trend that has been documented over the past 6 decades. The Pacific Decadal Oscillation includes a series of warming and cooling periods that occur in 20-30-year cycles. El Ninos is a periodic change of ocean atmosphere which includes increased ocean temperatures and decreased upwelling in the equatorial Pacific Ocean.
The main purpose of this site is to built up a bio-physical model for understanding and forecasting the consequences of El Niño and low-frequency climate forcing on pelagic ecosystems of the California Current and similar biomes.
Study of four mechanisms that may lead to rapid shifts in the California Current Ecosystem:
Observation of changes in the food web in response to changes in ocean stratification and the supply of nutrients
Transport of several organisms along the coast from the northern to the southern part of the California Current system (and vice versa).
Transport of organisms from the coast to regions located far offshore. Currents transport coastal species offshore away from their preferred habitat and this result in destruction of marine ecosystem.
Changes in predation.
The researches in the CCE- LTER site are based on following processes:
Experimental Process Studies:
This study focuses on the stratification of the water column and its effect on the food web. Stratification prevents the movement of nutrient reach water to the sea surface where the nutrients are needed for the growth of microscopic algae called phytoplankton. Amount of stratification varies across time and space. Researchers focus on the change of stratification across space. Divergences in the amount of nutrients of phytoplankton at different depths and in different places may cause species variation. Cyanobacteria which are the producer of the ocean’s food web are inhabited in the boundary between nutrient rich deep water and nutrient poor surface water. CCE LTER scientists are conducting studies to know the effect of ocean stratification on the Cyanobacteria and other organisms.
Time Series Studies:
Time series is a group of repeated, scientific measurements performed in the same place but at different times. CCE LTER usually takes 4 types of time series.
First type: measurements made at sea four times a year , and examine oceanic microbes organic matter dissolved in sea water concentration of several metal like iron, which is essential nutrient for marine plants and algae.
Second type: use satellite observation to measure pigments produced by phytoplankton and sea surface temperature.
Third type: uses more frequent measurements of phytoplankton and ocean temperature made at near shore sites including the Scripps pier, other locations along the coast in a network called the Southern California Coastal Ocean Observing Systems (SCCOOS), and the Ocean Institute at Dana Point.
Fourth type: robotic ocean gliders are used to make continuous measurements across the CCE region.
Computer models are used to interpret and understand the observation which is made during experiments. Information system contains the data from the various components of the CCE-LTER and allows researchers to access and combine all of those data. An Ocean Informatics electronic hub at the Integrative Oceanography Division (IOD) at the Scripps Institution of Oceanography control all the documentation and data associated with the CCE-LTER projects
Mark D. Ohman (SIO), Peter franks (SIO), Steven Bogard (PFEL), James E. Conners (SIO), Peter Davison (SIO) and many others.
There are many categories of stressors affecting the overall condition of the California Current ecosystem. This range includes traditional activities such as coastal development, fishing and emerging industries (shipping, renewable energy, desalination), the proliferation of land-based pollutants, and accelerating climate change. This stressor vigorously effects the marine population and marine ecosystem. Increase surface Temperature influences rates of metabolism and affects the range limits of many marine organisms. Scientists and researchers have shown that over the course of the past 60 years concentrations of dissolved oxygen have varied substantially. Periods of lower oxygen (hypoxia) reduce the vertical extent of habitable ocean for a variety of invertebrates and marine fishes and, while the habitable volume expands during intervals of higher dissolved oxygen (McClatchie et al. 2010). For the past 25 years gradual decline of dissolved oxygen has raised concerns about loss and compression of habitat for some commercially important rockfish such as the cowcod (Bograd et al. 2008).one study has shown that over past 60 years a group of marine zooplankton known as salps has been declined (Lavaniegos and Ohman 2007).Salps are very small celled suspension feeder and efficient grazer of phytoplankton and are important vectors that help repackage organic carbon and other compounds into a form that sediments quickly to the deep sea floor. Thus long-term carbon sequestration in the deep sea odd California may be altered by the decline in salps population. Another study has shown that the transparency of the California Current System has decreased slowly, but progressively over the past 6 decades (Aksnes and Ohman 2009). Seawater transparency plays a major role in controlling “encounter distance” at which visually-hunting predators like seabirds, fish, and some marine mammals can detect prey. The sustainability of some consumers that occupy the middle and upper levels of ocean food webs may be affected by deciline in encounter distance due to decrease in transparency of sea water.
Now scientist are not only trying to protect the California Current but also working to restore vitality and resilience in such a dynamic and changing system.