It’s Dry in Indiana ~ Bill Jones It has been another “feast or famine” year with precipitation here in Indiana. Despite a spring and early summer with abundant rain, the lack of significant precipitation during the past three months had left much of Indiana either dry or in a drought condition. Conditions are worse in the south where parts of Lawrence, Jackson, Washington, Jennings, and Scott counties are listed as “extreme drought” in the October 19 version of the Drought Monitor, published by the U.S. Department of Agriculture (http:// www.drought.unl.edu/dm/monitor.html). Much of the southern half of Indiana is listed as “severe drought” (Figure 1). The lack of rain has caused some low reservoir levels in southern Indiana. The U.S. Army Corps of Engineers reports that Monroe Reservoir, Indiana’s largest at 10,750 acres, is 2.4 feet below normal. So how much water is this, you may ask? A little calculation shows that the amount of Fall 2010 Vol. 22, No. 3 D0 Abnormally Dry D1 Drought – Moderate D2 Drought – Severe D3 Drought – Extreme D4 Drought – Exceptional Figure 1. The Drought Monitor shows that much of Indiana is dry or drought at this time. Clean Lakes Program • Office of Water Quality • Indiana Department of Environmental Management Water Column water needed to re-fill Lake Monroe particles from it. They ingest would more than enough to fill Zooplankton – edible particles and reject non- 800-acre Clear Lake in Steuben A Lake’s Best Friend edible particles. A community of County! zooplankton can filter through Salamonie Reservoir, a 2,600- ~ Dana Wilkinson the volume of an entire lake in a acre reservoir in Wabash and As an employee of the Indiana matter of days! However, not all Huntington counties is 4.4 feet Clean Lakes Program, I have the algae are edible and oftentimes it is below normal. Lake Lemon, a opportunity to view hundreds of the nuisance blue-green algae that 1,200-acre reservoir in northeast plankton samples from around zooplankton may avoid eating. For Monroe County is about 2 feet the state. Some of my favorite example, some blue-green algae are down. organisms to see are zooplankton. too large or have slimy, unpalatable Griffy Lake, a 109-acre reservoir So often as lake enthusiasts, we coatings that zooplankton grazers in Bloomington not only has think of the fish we love to catch do not like. suffered from the drought but or the algal blooms we hate to Zooplankton are also a also from an outlet structure stuck see, but what about all the other valuable food source for minnows partially open. The lake is down microscopic organisms swimming and young gamefish that are too some 6 feet and much of the lake around in the water? What role do small to eat insects or other fish. bottom is exposed (Figure 2). The they play in the health of our lakes? The presence or absence of healthy boat ramp is unusable (Figure 3). Zooplankton have an zooplankton populations are Bloomington’s precipitation since important and essential role essential for a healthy fishery in a July is some 8 inches below normal. in a lake’s ecosystem and food lake or even the ocean. By insuring While northern Indiana isn’t chain (Figure 1). Unlike algae, or that the lower parts of the food as droughty, according to USGS phytoplankton, zooplankton are chain are healthy, we can protect data for lakes and reservoirs (http:// microscopic animals – shrimp-like the higher ordered organisms, like in.water.usgs.gov/) Lake Maxinkuckee crustaceans that are responsible for fish, whales, and even us humans. in Marshall County has dropped 1 eating millions of tiny algae that Below I’ve shared a little bit foot in the past two months. Over may otherwise grow to an out- about some specific zooplankton the same time period, Waldron of-control state. Zooplankton are groups that I often see in Indiana Lake in Noble County is down grazers, having the same function lakes. nearly 3.5 feet from high levels as rabbits or cows on the land. The following the wet spring. big difference is that they are very Rotifers For the year, precipitation tiny. There are over 2,000 species amounts in Indiana are near Zooplankton are primarily of rotifers in freshwater systems. average, however, the irregular filter feeders. They passively filter They are so named for their distinct timing of precipitation events is lake water, extracting small food mouth, called a corona. It is used causing the lake level problems. Figure 2. The drought and a leaky outlet have left much of Griffy Figure 3. Boats have no place to go in Griffy Lake. Lake in Monroe County dry. 2 for both locomotion and filter feeding (Figure 2). Fine cilia (hairs) in the corona rotate to create water currents that bring food to the mouth. Because they are so small, less than 1 millimeter (mm) in size, they can only consume very small Piscivorous Fish particles. (A millimeter is the width of an “e” on this page.) Rotifers serve as a food source eat for larger organisms, including other zooplankton. Most do not swim and must simply drift along with the water, as many plankton Figure 3. A Daphnia female with three do. Others have a single foot embryos in its brood chamber. Photo by Bill and remain attached to the lake Jones. Planktivorous Fish bottom or to plants. Rotifers are very efficient reproducers and can on algae, detritus, and bacteria, multiply asexually when conditions and can take larger particles than eat are suitable. They eat bacteria, can the rotifers. As filter feeders, detritus, other rotifers, algae, and they use their legs to create a flow protozoa. of water past their mouths to then suck up food particles. The fine Cladocerans hairs on their legs also act as filters These small crustaceans are and can catch food drifting by. characterized by a two-valve Daphnia, also known as water carapace, or outer shell, covering fleas, are able to move in the water, Herbivores most of their body (Figure 3). in a very unique, jerky manner by Examples of this group include moving their large antennas in a Daphnia, Bosmina, Ceriodaphnia, paddling motion. When viewing eat and Diaphanosoma; all of which live specimens on the microscope, look very similar except for very it can be very frustrating to keep small differences in body shape. them in the field of view! Some of them grow large enough Several different genera of (2-3 mm) to be spotted with the Cladocerans are seen in most lake naked eye when captured in a samples that I count in the Clean Algae light-colored container. They feed Lakes laboratory. For instance, I saw quite an abundance of Daphnia longiremis, among many other use zooplankton genera, in Lake Cicott of Cass County this past summer. The number of zooplankton we catch in one sample can often Nutrients be determined by the quality or quantity of current algal food sources, time of day, or sampling technique. recycle Daphnia, and several other zooplankton, perform what is known as “diurnal migration.” Benthivorous Fish This is a daily routine of migrating from the darker, deeper waters of the lake during the day and up to the surface waters during the night. Scientists believe they do this to avoid predators. By spending Figure 2. A rotifer, Testudinella. Photo by daylight hours in the dark, deeper Figure 1. A typical aquatic food chain. Micrographia. waters, Daphnia can avoid being 3 eaten by sight-feeding fish. They the life cycle typically includes six then migrate up to the surface stages as a nauplii and six stages as Announcement waters at night to filter feed on the a copepod, the last of which is the of Watershed algae. Most fish don’t feed at night. adult stage. Developing copepods For this diurnal migration strategy shed their old, small exoskeleton Networking Sessions to succeed, there needs to be plenty (outer shell) at each stage and grow Seeking Grants to Meet Your Goals of oxygen in the dark, deep-water a new, larger one. As filter feeders, and Leveraging Funding Sources is refuge. Unfortunately, many lakes they feed mainly on phytoplankton the title of three sessions that have don’t contain enough oxygen at and protozoans, but some species been set up to discuss this timely depth. are predatory. Copepods can be topic. They will cover the same strong swimmers and will also material, so just choose the session Copepods undergo diurnal migration. They closest to you. They will be held Two notable copepods that I see are an important link that connects from 10:00 a.m. to 3:00 p.m. each often are calanoids and cyclopoids food webs between small, algal cells day. (Figure 4). As larva they are known all the way up to large fish. as nauplii (Figure 5). A copepod egg Next time you’re out on a Topics will include: Getting hatches into a nauplius larva and sunny, summer day, dip a white Ready to Seek Funding; Seeking the cup into the water, and see if Right Grants and Other Funding you can’t spy any tiny organisms Sources; Grants and Funding in moving about in the water. General; and Specific Grants and Other Funding Sources December 1, 2010: LARE Reports Potato Creek State Park Available Online North Liberty, Indiana Greg Biberdorf of the Indiana (574) 656-8186 DNR Lake and River Enhancement Program (LARE) tells us that all December 8, 2010: LARE final reports, nearly 400 in all, Spring Mill State Park are now available in a searchable Mitchell, Indiana database at: http://www.in.gov/dnr/ (812) 849-4129 fishwild/3303.htm.