Invertebrates By Kotpal Torrent Download
Dardo Hameed
Invertebrates are a diverse group of cold-blooded organisms that do not have or develop a backbone at any stage of their lives (Buchsbaum, Milne, 1960). They are so diverse in their structure, physiology, habitat, and behavior that they constitute approximately 95% of the total identified animal species on earth. With over 30 phyla, they are spread throughout the world and can be found in seas, oceans, freshwater bodies, in air, and on all kinds of land (Kotpal, 2009).
Freshwater invertebrates are the primary focus of our research, more specifically, macroscopic pond invertebrates. All the major phyla except for Echinodermata have freshwater representatives. Some are more diverse in freshwater ecosystems, e.g., Rotifera (zooplankton), Nematoda (roundworms), Mollusca (snails and bivalves), Annelida (leeches), and Arthropoda (aquatic insects, crustaceans, etc.) (Thorp, Covich, 2010). They serve as integral members of freshwater ecosystems by performing various important functions like processing organic matter, controlling algae population, feeding aquatic life, etc. They are also good indicators of water quality and habitat health (Thorp, Rogers, 2011).
The diversity and abundance of aquatic invertebrates are influenced by various environmental factors such as, temperature, oxygen level, acidity of water (pH level), water hardness (salinity), pond depth, and pollution from human activities. (Thorp, Rogers, 2011). Pond size can also affect the abundance and diversity of invertebrates to some extent (Oertli et al., 2002). Vegetation around a pond can also affect species diversity by altering the pH level of water. Coniferous trees around water bodies are responsible for acidification and release of humic acid into the water (Thorp, Rogers, 2011).Therefore, the survival of these aquatic invertebrates depends on the quality of the water in which they spend part or all their lives in; hence, the abundance and diversity of these macroinvertebrates serve as potential ecological indicators of the water quality (Breabăn et al., 2012). With invertebrates making up such a large portion of the total documented species on earth, understanding the factors that influence their survival and abundance is vital.
Humans have always greatly affected the land which they inhabit. A pond that is in an agricultural landscape for example, is susceptible to multiple pressure factors related to the eutrophication of the water. The addition of farm pollutants such as fertilizers and nutrients (nitrogen and phosphorus) caused by runoff has been shown to affect the composition of the water (Kadoya et al., 2011). This includes chlorophyll-a concentrations, total phosphorous, cyanobacteria, suspended solids and total nitrogen all of which will then affect the composition and diversity of macroinvertebrates. In fact, eutrophication of a pond will shift the regime from macrophyte abundant to phytoplankton abundant (Kadoya et al., 2011), leading to a significant impact on invertebrates since aquatic macrophytes can shelter and provide nutrients for them (Ali et al., 2007)
To answer this question, we sampled two different ponds in the Morgan arboretum forested reserve. The first pond was located next to an agricultural field and the second pond was located deep in the wooded area of the arboretum. Sampling was preformed once a week over a period of three weeks. Both ponds were divided into sites and each site was sampled at least 3 times. The sites were sampled by performing 1m sweeps a total of five times through the water. The invertebrates collected after these five sweeps were then counted and identified. It is to be noted that each organism caught and counted was later released back to where it was collected. Being mindful that abiotic pond characteristics can affect macroinvertebrate diversity and abundance, we also collected pH, water temperature, pond shape, weather, and surrounding tree composition data.
Based on observations alone, our research thus far has shown that there is a higher abundance and diversity of invertebrates found in the agricultural pond. This could be explained by multiple factors including, eutrophication caused by the crop runoff increasing the nutrient load into the pond and therefore encouraging primary productivity. As well higher concentrations of light entering the agricultural pond due to less trees surrounding the area.
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