“How Healthy Is the Bay?” Project by 6th Grade Student Contributor

The well-being of the Bay Area has been greatly influenced by varied factors ranging from the most complicated to the simplest ones. But do we practically know if our Bay Area is generally in good shape or its cleanliness in terms of water has declined recently? Realistically speaking, this area is where we, the students and educators of the Cambrian International Academy (CIA), are situated every day to either achieve our academic knowledge or pass down the intelligence acquired years ago – sadly enough we haven’t known how healthy it is. We decided to investigate different aspects of the Bay in different areas in its scope by setting sail to collect samples of water to analyze at three sites: South Bay, Central Bay and area under the Golden Gate Bridge. The characteristics of the obtained water that we wanted to interpret were plankton, water quality and bioacoustics.


  1. Plankton  
  2. Data:
  3. Plankton is the essential base of the ecosystem as well as the primary producer occupying at the Bay which plays the role as the main source of food for other higher-class consumers. Naturally, this is one of the most crucial features of the Bay because it reflects how capably the Bay can provide such organisms with sufficient nutrition and whether there is enough pollution to limit the diversity as well as the abundance of plankton in the Bay. In light of this, we observed the tiny plankton living in the Bay by dropping some water collected at the three mentioned sites onto glass slides and observing those under the microscope.

Sample 1 (from South Bay)#Sample 2 (from Central Bay)#Sample 3(from Area under Golden Gate Bridge)#

Calanoid Copepod35Calanoid Copepod68Calanoid Copepod26

Harpacticoid Copepod6Harpacticoid Copepod10Globigerina Bulloides10

Fish Larva5Early Fish Embryo12Early Fish Embryo2

Unidentified Rotifers1Unidentified Rotifers1Unidentified Rotifers2

Pseudo Nitzschia Australis1Cyclopoid Copepod1Crustacean Nauplius6

Actinotroch Larva2Cypris Larva2Evadne Spinifera4

Egg Sac1Nauplius Larva5Fish Larva2

Mid-gastropod Larva1Mid trochophore Larva5

Late trochophore Larva2

California Spiny Lobster1

Phyllosoma Larva1



Some footage photos of our observation of the plankton



The most noticeable feature of the table shown is apparently the number of Calanoid Copepods present at 3 sites: quantity of Calanoid begins at 35, then rises to 68 as it approaches to Central Bay, and eventually has a dip from there to 26 individuals when it reaches the area under Golden Gate Bridge. This reflects the abundance of this particular type of Copepod living at the Bay. The up and down in terms of the number of Calanoid Copepods can be used to state a general hypothesis: South Bay is where the least abundance of planktonic organisms can be observed and, to accompany with, the area under Golden Gate Bridge is where the second least number of plankton inhabit; meanwhile, Central Bay is the most plankton-concentrated site with its number of Calanoid Copepods exceeds that of the other two sites. However, while being short of Calanoid Copepods when compared to the South Bay and Central Bay, the area under the Golden Gate Bridge actually possesses the larger biodiversity than do the other two locations, evidently by the count of different species being 11 (while the others being 7 and 8, respectively). Particularly speaking, the variety of larva in the area under Golden Gate Bridge is relatively greater than that in the other two spots: there are, based on the data, 4 types in this area, including fish larva, mid-trochophore larva, late-trochophore larva and phyllosoma larva, while the others have around 3 types.



In conclusion, I would like to put forward within my own perspective a thought that is based on the generally upward motion in the data: Central Bay is the location where the plankton favor the most to inhabit; the area under the Golden Gate Bridge is on the other end of the spectrum the area where offspring of microscopic organisms are bred and nurtured at early age; finally, South Bay is the most unfavorable site for the plankton to live in as this area has, according to the data table, the least number of both overall total organisms collected and different species of plankton. I personally think that plankton begin to move from the area under the Golden Gate Bridge to Central Bay when they reach a decent and mature enough age, then the same principle is applied when older-aged plankton migrate to South Bay and the newly-bred larva and some plankton could possibly perish along the way due to the incapability to cope with strange environments.

Until my proposed idea is acknowledged, we could still further investigate by setting sail around the Bay to see if the species present at the South Bay and Central Bay are also present in the area under the Golden Gate Bridge. If that is proven, my hypothesis would be true. Nonetheless, the health of the Bay has generally remained stable until now based on the diversity and abundance of plankton shown in the table.


  1. Water quality:
  2. Data:
  3. Water quality, which is one of the factors that determines the abundance and biodiversity of plankton as well as those of the other organisms, is no less noteworthy than Plankton in this project. Without at least decent water quality, the Bay couldn’t have maintained many of the most basic types of marine organisms. Water quality refers to the chemical, physical, biological, and radiological characteristics of water [1]. In this particular lab, we only conducted experiments to measure the levels of the following characteristics: pH, salinity, NO3 and PO3.

Water Quality

CharacteristicsFrom South BayFrom Central BayFrom Area under Golden Gate Bridge

pH level776.5


NO3­ level0 – 5.0 ppm5.0 ppm5.0 ppm

PO3 level1.0 ppm0.25 ppm0.0 ppm




Some footage photos of our measurements of NO3 and PO3



The first two sections of data express the overall percent of Hydrogen (pH) and salinity of the 3 areas. In terms of the pH level, it is notable that there is a slight decrease when looking from South Bay to the area under Golden Gate Bridge: pH level at South Bay is measured 7 on the scale while that in the area under Golden Gate Bridge amounts to 6.5. However, in regard to the salinity at the 3 sites, there is a small increase along the way from South Bay to the area under Golden Gate Bridge and the difference is .002 of whatever unit to measure salinity. Next, it is observable that according to the table, NO3level grows from around 0 ppm to approximately less than 5 ppm, at South Bay, to exactly 5 ppm in the area under Golden Gate Bridge. Finally, the level of PO3, on the other hand, has a decline from 1.0 ppm to 0.0 ppm in the same order of locations. These last two sections of data, I believe, reflect the amount of organic substances that are provided for organisms living in the 3 sites mentioned.



To conclude, I would say that the area under Golden Gate Bridge is where the most salinity and acidity are present, which may correspond to the hypothesis proposed in the Plankton experiment that such factors are suitable for innate and young plankton. Whilst, South Bay is not chosen as a breeding area because it doesn’t provide enough salinity like the area under Golden Gate Bridge does. In terms of NO­3 level, unlike South Bay, North Bay and the area under Golden Gate Bridge actually have the most amount of organic NO­3 which is 5.0 ppm; this may suggest that correspondingly, NO3 is much needed for phytoplankton, which would be eaten by other types of organisms, to develop. With respect to the PO3 level, South Bay has the most whereas the area under Golden Gate Bridge has the least or none. But in essence, it’s not the scarcest nor the largest amount of PO3 that matters as “in the context of pollution, phosphates are one component of total dissolved solids, a major indicator of water quality, but not all phosphorus is in a molecular form which algae can break down and consume” [2], rather it’s the sufficient amount that can cater to the plankton and by that, I refer to the amount of PO3 in Central Bay. Overall, we can see that Central Bay possesses accurately enough amounts of the 4 particular criteria shown in the table to supply enough nutrients for its population of plankton: 7 on the scale of pH, 1.034 on the scale of salinity, 5.0 ppm on the scale of NO3 and 0.25 ppm in terms of PO3.

For further interpretation on this, I suggest we measure the levels of some more substances or compounds like O2, CO2, etc. to examine this particular aspect – water quality – of judging how healthy the Bay is. All in all, I would say that the Bay Area is relatively healthy in terms of water quality when analyzing the correlations of the 3 sites.


  1. Bioacoustics:
  2. Data:
  3. Finally, the last feature that we decided to look at was marine bioacoustics. Generally speaking, bioacoustics refers to the investigation of sound production, dispersion and reception in animals [3]. We recorded audio clips under the water around the Bay to analyze the bioacoustics of it in order to find out if there is sound pollution that could potentially interrupt communication of organisms or overwhelm the soundings of marine and planktonic organisms or even scare them. In essence, bioacoustics is essentially as important as the other features when it comes to determine the health of the Bay.

AreasBiotic SoundingsAbiotic Soundings

Mid Bay (South Bay)Ø  Length: 3:00·         Crackling·         Tic-a-tic·         Humming·         A little boats’ engines

Angel Island (Central Bay)Ø  Length: 7:24·         Barely crackling·         Humming·         Wobbling


·         Boats’ engines (80% of the time)

Golden Gate BridgeØ  Length: 4:16·         Crackling·         Humming·         Boats’ engines


(almost all of the time)



For Mid Bay (Mid Bay) whose audio clip recorded lasts 3 minutes, in terms of its abiotic soundings, we have recorded that there are 2 types: the humming and a little of boat’s engines’ roaring; in addition, in terms of its biotic soundings, there are crackling and tic-a-tic soundings. These mean that there is just a small portion of soundings intervening noises of the organisms, which also mean that there is a slight sense of sound pollution.

For Central Bay (Angel Island) whose audio clip recorded lasts 7 minutes and 24 seconds, it was documented that there are humming, wobbling and 80%-of-the-time boats’ engines’ roaring as abiotic soundings, and a bare sounding of crackling. Significantly enough, since the audio clip has a timespan of about 7:30, the fact that abiotic soundings outran biotic soundings can be interpreted that there are more interrupting artificial noises in Central Bay than in South Bay, and sound pollution occurs here more considerably than any other sites.

For Golden Gate Bridge’s area, the abiotic soundings recorded were the prevalently loud boats’ engines’ and humming, whereas the only biotic sounding was the crackling. What can be suggested from this can be compressed into a hypothesis that states: if there is more boats’ engines’ roaring, the total number of plankton, rather than the biodiversity of organisms, in the area under Golden Gate Bridge would decrease.




The data of bioacoustics at the 3 locations have shown that, except South Bay, the examined locations experience mostly boats’ engines’ roaring rather than any biotic soundings. This particular piece of information may infer that sound pollution caused by man-made mechanical machines and motors in Angel Island’s and Golden Gate Bridge’s areas affects greatly life of marine and planktonic organisms. In addition, there is also data which reveals that biotic soundings occur in South Bay more often than in the rest, which in turn says that there should be relatively a large amount of plankton here; but, instead the number of plankton in South Bay is reported to be the least when compared to that of the other 2 sites. So, bioacoustics may not be an effective indication of the abundance of plankton or the health of the Bay Area.

However, the fact that we only conducted the recordings at daytime (from 10 A.M upward) may not be sufficient to state any contradictions between plankton’s and bioacoustics’ figures because if recorded in conditions where it is quieter, audio clips might manifest soundings that correspond correctly to the data displayed in Plankton’s table, which in turn would be more understandable. For this reason, my only recommendation is to conduct one or more bio-acoustical sets of recordings at nighttime to further explore on abiotic and biotic soundings of the Bay.


  • Conclusion:      Nevertheless, I would say that the Bay maintains fairly sufficient sources of nutrition for its inhabitants to live on. As long as we, the people, are aware of how different types of pollution are factors that can potentially have negative effects on the health of the Bay, and learn how to not produce more of them, our Bay will remain as healthy as it is today.


  •       Though no authorities, we, CIA’s conductors of this project, have found that the Bay is generally healthy. But further experiments and documentations can help us evaluate if the Bay is really exactly according to this first-and-foremost Bay project done by CIA’s students and teachers.





[1]: Diersing, N. (2009). Water Quality: Frequently Asked Questions. Florida Keys National

Marine Sanctuary. http://floridakeys.noaa.gov/scisummaries/wqfaq.pdf.


[2]: Hochanadel, D. (December 20, 2010). Limited amount of total phosphorus actually feeds

algae, study finds. http://www.lakescientist.com/limited-amount-of-total-phosphorus-actually-feeds-algae-study-finds/


[3]: Bioacoustics’ Editors. (July 31, 2012). Bioacoustics – the International Journal of Animal

Sound and its Recording. http://www.bioacoustics.info/