1 Investigating and Examining Invertebrates Living in the Mud of Zones 1, 3, and of the Ala Wai Estuary Team FarronTrons (Farron Choe, Amber Alualu, John Zobian, Borys Pleskacz) Abstract: Our group investigated the different invertebrates living in zones 1, and of the Ala Wai mud We deployed a set of plates into the mud, gave them two weeks for a biofilm to form, and collected them Next our group filtered the invertebrates through a plankton net, scraped off the plates, and examined under microscopes We noted the different types of invertebrates and their concentrations in zones 1, 3, and Invertebrates that we discovered include amphipods, nematodes, annelids, insect larvae, and copepods We also found that there were no trends showing different concentrations of specific invertebrates in certain zones, but there were slight differences between the first two collections The third collection yielded huge amounts of amphipods due to the amount of rainfall and detritus in the water There was a lot of inaccuracy in our counting due to the detritus in the water, the difficulty of counting the specimens, and other factors 2 Introduction: Estuaries are semi-enclosed bodies of water where fresh and salt water mix Salinity levels can vary depending on the flow of fresh water sources and the tide of the ocean Fresh water is less dense and tends to float above the denser salt water The time it takes for all the estuary water to cycle is called flushing time Estuaries are some of the most biologically productive places on the planet, and are places for organisms to breed and find food (Judith S Weis, 2008) The food chain of estuaries is driven by the water plants, bottom-dwelling algae, and other living organisms that convert the sun’s energy into food energy After these plants and algae go through their growth cycle and die, they’re covered by protozoa, fungi, bacteria, and other microorganisms (detritus) These protozoa and microorganisms are in turn consumed by invertebrates Invertebrates are eaten by fish, and fish are consumed by birds and animals Since tides replenish oxygen levels for other living organisms in the ecosystem and bacteria and other microorganisms use up a lot of oxygen, tides are essential to this cycle (Judith S Weis, 2008) Amphipods have seven pairs of walking legs, four pairs that reach forward and five to seven pairs that reach backward The first pair of legs may also be modified in order to help grasp food (claws) Amphipods are typically less than 10 millimeters long, however, there was one rare case of a 28-centimeter amphipod that was found in the depths of the Atlantic Ocean The sizes of amphipods are limited by the availability of dissolved oxygen There are two different types of amphipods that are found in shallow marine environments: Caprellidae and Gammaridae Caprellidae have long, skinny bodies whereas the Gammaridae have bodies that are flattened on each side The diet of the amphipod depends on the habitat they live in While amphipods living on seaweed may be herbivores, amphipods that live in the Ala Wai feed off of detritus or scavenge off of dead animals or plants In an ecosystem, amphipods are usually the next step up from plankton and are eaten by fish (Museum Victoria, accessed 2010) Nematodes are one of the most abundant animals on the Earth Nematodes are nonsegmented roundworms that have long and narrow simple structured internal body cavities called pseudocoeloms They can be free-living and predaceous, which means predatory or parasitic Free-living nematodes feed on either bacteria or fungus, while predaceous nematodes eat all types of nematodes and protozoa Other nematodes that are omnivores, including plant parasites, are root-feeders (Elaine R Ingham, 1996) Nematodes can also can undergo cryptobiosis, the ability to slow down or stop metabolic processes when they are in unfavorable environmental conditions so that they can survive extreme aridity, heat, or cold, and then return to their metabolic state of life when favorable conditions return (David I Shapiro-Ilan & Randy Gaugler, accessed 2010) Annelids, which are long cylindrical shaped worms, are a type of invertebrate that have a body cavity (coelom), movable bristles (setae), and a body divided into segments They not have appendages, antennae, or an obvious head end This phylum is divided into three classes: earthworms (Oligochaeta) and their relatives, leeches (Hirudinea), and a large number of marine worms (polychaetes) Most earthworms feed on a wide variety organic matter, primarily detritus and algae which can be found in the Ala Wai As they feed they dispose what they not need in castings which are high in nutrients and in turn become food for other animals (Bellarmine University, accessed 2010) Materials: • 145mm by 152mm by 5mm wood plates, attached by a screw with wood spacers in between each plate • Rope and mini-buoy to float the rope attached to the plates • Buckets • Nets • Brushes to Scrape off Plates • Plankton Net • Petri Dishes • Pipettes • Microscopes Procedure: Deploy set of plates in zones 1, and Allow a two week period for biofilm to accumulate on the plates Prepare buckets (one for each zone) and fishing nets (one for each bucket) Add water from one zone into the bucket for zone Withdraw plates and be sure to hold the zone net under the plates to catch any excess organisms from falling out of the plates Drop the zone plates into the zone bucket Repeats steps and with the remaining two zones Use a plankton net to extract the sediments and organisms from the water for one zone Keep filtering until all sediments and organisms from one zone is accounted for Once all sediments and organisms from one zone is in a petri dish, use a sterile pipette to withdraw some zone matter (cutting the tips of the pipettes would help to withdraw more matter) and examine under a microscope Use tank water to dilute the matter that is examined in order to view specimens clearer Once specimens are thoroughly examined and classified from one zone, discard specimens 5 10 Repeat steps though for the remaining two zones (Specimens may be refrigerated to be examined at a further time.) Data: 1st Collection: Zone Zone Zone annelids (average length 0.5mm-10mm) 11 annelids annelids 13 amphipods (1-2mm) amphipods (1-5mm) amphipods (2-4mm) nematodes (0.5mm-1.5mm) nematodes nematode (2.5mm) Pictures from Zone 1… Zone Nematode Zone Amphipod 2nd Collection: Zone *N/A* Zone annelids *Zone plates were lost 12 amphipods Zone annelids 10 amphipods due to heavy rainfall* pregnant amphipods pregnant amphipods nematode nematode Unknown fly larvae 3rd Collection: Zone *N/A* Zone annelids *Zone plates were not 184 amphipods Zone 11 annelids 215 amphipods deployed due to lack of pregnant amphipods 10 pregnant amphipods plates* nematodes 11 nematodes Chironomid Larvae Chironomid larvae Copepod Copepods Pictures from Collection 3… Zone Copepod Zone Pregnant Amphipod Zone Chironomid larvae Zone Amphipod Zone Pregnant Amphipod Zone Amphipod Zone Annelid Discussion: All three collection dates yielded different results In comparison to the zero annelids and two nematodes found in the second collection, many annelids and nematodes were counted in the first collection The number of amphipods stayed relatively the same between both collections, considering the fact that we did not have plates for zone This could be due to the fact that the conditions during the first collection were prime for annelids and nematodes (both worm-like) to reside on the plates It could also be due to miscounting The third collection yielded 17 annelids and 11 nematodes, which is more than collection two and close to collection one The number of amphipods, however, was in the hundreds due to the heavy rain occurring around the time of collection three The heavy rain could have caused more amphipods to cling to the plates, or may have had something to with the living patterns of amphipods in our section of the Ala Wai (they may have flowed in from other sections or been unearthed from the mud by all the rainfall) Also, since the amphipods feed off of detritus including decayed leaves and other debris that could have been unearthed and brought into the zones because of the rain, we found unusually large numbers of amphipods in the debris in our samples This could also have contributed to the 399 amphipods we counted in collection three, as opposed to collection one and three each having 22 amphipods The size of amphipods may be dependent on the amount of dissolved oxygen in the water It is possible that the rain dissolved more oxygen in the water, allowing the amphipods in collection three to reach a larger size than in previous collections With more dissolved oxygen in the Ala Wai, more amphipods are able to inhabit the same area While examining the different invertebrates in zones 1, and 5, it was observed that the variety of invertebrates remained fairly the same throughout all three zones Although we are lacking two collections of zone 1, the numbers of discovered invertebrates seem very random and show no trends as to whether specific invertebrates prefer specific zones Furthermore, within these zones, unique characteristics of the invertebrates were observed While examining the amphipods, a wide variety of different amphipods were seen 8 Some amphipods were pregnant, which was implied by the large sac of green colored eggs in the abdomen area, other amphipods exibited different coloration or structural differences Most amphipods were pinkish or grayish in color; however, yellowish-golden colored amphipods were also seen Size differences many have occurred due to the age variations of the amphipods and gender probably determined whether or not the amphipod would have claws The large, fully grown pregnant amphipods had small claws whereas other amphipods of the same size had large claws There were also amphipods with underdeveloped claws, but with large fins that allowed those amphipods to swim quickly in the water These noted differences existed probably because different species of amphipods reside in the mud of the Ala Wai It is important to note, however, several experimental discrepancies may have lead to error in counting the number of organisms found in each zone Due to the small size of the nematodes, we were not able to accurately count all of them Many could have been missed or thrown out due to the inexact nature of our procedure Since the organisms were refrigerated, the nematodes may have been mistaken for detritus This same problem may have occurred with all of the specimens, since these microorganisms were mixed with debris from the Ala Wai In addition, due to heavy rain storms that occurred throughout the time period the plates were deployed in the water, plates tended to shift downward into other zones As a result, in collections and 3, the data is slightly inaccurate since the zone plate floated downward into the next zone, zone Thus organisms from the original zone and next zone the plates were in could have been mixed together Another error would be due to our procedure Since our group withdrew sample Ala Wai water from the surface and put it into the buckets before adding the plates, specimens could have been in the surface water and may have affected our numbers 9 Conclusion • We deployed wood plates with spacers into zones 1, 3, and to sit for two weeks and form biofilm After two weeks, we collected the plates and examined the specimens on them • We found that there were no trends in specific invertebrates residing in certain zones, and that the numbers seemed fairly random Also, after heavy rainfall the number of amphipods in the zones increased greatly • Further experimentation can be done through conducting a more thorough analysis of the invertebrates living in the Ala Wai mud Multiple sets of plates can be deployed in each zone in order to minimize error • Given the time for more thorough research, a further more precise experiment could be conducted If students research exactly what each invertebrate eats, baited traps can be used to study one specific invertebrate • Our data probably could not be extrapolated to all other estuaries; however, our data does give a better understanding of the organisms that live within the depths of our local Ala Wai Estuary Works Cited “Annelids.” Accessed Novermber 23, 2010 From Bellarmine University “Annelida - worms and leeches.” Accessed November 23, 2010 From CSIRO Entomology Home David I Shapiro-Ilan & Randy Gaugler “Nematodes.” Accessed November 23, 2010 From Cornell University's New York State Agricultural Experiment Station 10 Elaine R Ingham “Soil Nematodes | NRCS SQ.” (1996) Accessed November 23, 2010 From NRCS Soils Hinterland’s Who’s Who “Estuaries Habitat for Wildlife.” Accessed November 22, 2010 From Canadian Wildlife Service “The Biology of Amphipods.” Accessed November 23, 2010 From Museum Victoria Waggoner, Ben “Introduction to the Nematoda” Accessed November 23, 2010 From University of California Museum of Paleontology Weis, Judith S “Estuary” (2008) Accessed November 22, 2010 From The Encyclopedia of Earth ... heavy rainfall the number of amphipods in the zones increased greatly • Further experimentation can be done through conducting a more thorough analysis of the invertebrates living in the Ala Wai. .. to with the living patterns of amphipods in our section of the Ala Wai (they may have flowed in from other sections or been unearthed from the mud by all the rainfall) Also, since the amphipods... amphipods are able to inhabit the same area While examining the different invertebrates in zones 1, and 5, it was observed that the variety of invertebrates remained fairly the same throughout