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Sunday, June 18, 2023

I Scream, You Scream, We All Scream for Isoprene

Plants are well known for absorbing carbon dioxide from the atmosphere and replacing it with oxygen as part of the photosynthesis process. But that’s not the only thing they put into the air. Trees emit tons of a chemical known as isoprene every year, mostly during summer months. It’s surprising to learn that plants contribute to air pollution. 

An abundance of isoprene can lead to formation of greater amounts of ozone by combining with nitrogen in the form of NO and NO2. Ozone in higher levels of the atmosphere is good because it blocks harmful UV rays from the sun, but at our level it’s a major pollutant.  

The current theory is that plants produce isoprene as a method of heat resistance. Like water vapor and oxygen, it is emitted through the pores in a plant’s leaf. Not every plant produces isoprene, but the biggest producers in the US are oaks and poplars.  

Shenandoah National Park (NPS)

Isoprene is what gives the Blue Ridge Mountains their blue appearance. The chemical haze scatters blue light, which makes the mountains appear blue from a distance. It also gives the Smoky Mountains their smoky appearance. 

Great Smoky Mountains (NPS)

We learn such shocking things about nature. I had no idea before today that plants are polluting the air with volatile organic compounds, which when man-made seem to be about the worst thing under the sun. Yet here they are, also giving some of our national parks their distinguishing features and even namesakes. 

Information comes from National Center for Biotechnology Information and Department of Energy Office of Science.

Sunday, February 19, 2023

Winter Seals

Since moving from the Northwest to the Northeast 5 1/2 years ago I haven't been going on as many excursions into the natural world, especially during winter. But I decided to make an exception and visit the Jersey Shore to see some seals that I heard were visiting. My first attempt was postponed a week due to bitter cold. The second attempt was still chilly, but a much nicer day. To top it all off, I met up with some friends I hadn't seen since moving from the Northeast to the Northwest over 15 years ago. 

Four seals visit New Jersey in the winter months. They are the harbor seal (most common), gray seal, harp seal, and hooded seal (least common). The seals I saw were harbor seals, and there were two or three dozen of them. After spring arrives, the seals return north to Canada and New England. Since it was getting to be the end of their time in my neck of the beach, I put my discomfort aside and ventured outdoors. 

I arrived in the Sandy Hook area early, so I stopped by the Twin Lights State Historic Site for a quick view. The lighthouse is on top of a hill about 200 feet above sea level, one of the highest coastal points along the Atlantic. From the heights you can see just how narrow the Sandy Hook peninsula is. A few turkey vultures down the hill were basking in the sun.
Sandy Hook seen from Twin Lights
Seals haul out when the tides are low, so I had to check a tide table to plan my trip. Low tides were around 5 AM and 5 PM. I opted for the evening low since there's still light at that hour. And because I didn't want to get up at 3 in the morning on a Saturday. The exact time of the low tide wasn't important. Seals don't wait until the tide reaches its lowest point to haul out. A few hours early was fine, and the seals were at the appointed location ahead of me and my entourage. A small crowd was gathered along a fence, looking into the bay. I said "I bet those rocks everyone is looking at are actually seals." Sure enough, one of the "rocks" moved. 
Harbor seals in Sandy Hook Bay

Harbor seals in Sandy Hook Bay through a scope (NPS photo)


It's important to keep your distance from seals (or any other marine life) not just because it's a federal law, but because seals especially are easily annoyed and will leave if disturbed. Any unnecessary movement burns valuable calories that are keeping them warm. And there's a reason they're on land, so let them stay there doing seal things. There could be any number of reasons for seals to haul out. They bask in the sun to warm up, just like reptiles and amphibians. Mother seals nurse their pups on land. They need to rest just like we do. Their time in the water is spent hunting prey and trying not to become prey. It's exhausting.

I'm glad the day went how it did. Usually wildlife can sense me coming, and I wind up seeing nothing except some tracks and scats. But the seals didn't disappoint. It was great seeing my friends again, and since one is a shark enthusiast, it was a thrill for her to see shark food in its natural environment. In spite of the chill, I would make this an annual tradition.

Seal information came from Conserve Wildlife Foundation of New Jersey. The NPS picture of seals comes from a post on Gateway National Recreation Area's Facebook page

Sunday, October 30, 2022

Going Batty

International Bat Week, a global celebration of the world's most misunderstood mammal, fittingly comes to a close tomorrow on Halloween. To celebrate, let's take a trip down memory lane to that time five years ago when I helped with a bat colony count. It was late summer in 2017. I was just a few weeks away from leaving the Northwest and returning to my native Pennsylvania. I was invited to a pot luck for volunteers at Northwest Trek, a wildlife park in Eatonville, WA. I'd worked with them doing amphibian egg mass surveys for the state and nature mapping for Nisqually Land Trust. There was also a bat colony count happening that night, and I was asked if I would like to join. Of course I said yes. After white nose syndrome was detected in Washington, the state fish and wildlife service wanted to colony counts to establish a baseline population for monitoring purposes. Having worked on other conservation projects with Northwest Trek it was only natural that they would ask them to partner up again. And it was a no-brainer for me to get in on the action. After eating, we took an extended afterhours tram ride through the free roaming area to see the deer, elk, bison, moose, mountain goats, and bighorn sheep who don't know they're lving in captivity. There's nothing wrong with a little extra time hanging out with our animal friends. Afterwards, we returned to the park entrance. I was supposed to monitor the comings and goings at a bat box inside the park just inside the entrance. All I had to do was count how bats flew out and how many flew in, until I couldn't see anymore. Ins and outs, then subtract and the difference is my count. Very simple. But the bats had other plans for the night. Before we even got inside we could hear bats moving around inside the roof of the entrance. I never made it in. Instead, I stood outside the entrance counting bats. I watched as a little bat would drop down from the roof and gain altitude as it moved towards me. I only ducked once or twice. It was just instinct. I knew they wouldn't hit me. I figured with their echolocation they could tell where I was long before I saw them. I could hear theirs wings flapping and feel the breeze as they zipped past my head. At the end of the night, all the participants gathered to turn in their tally sheets. The counting station at the entrance, which wasn't on the list at the beginning, and was almost an afterthought, turned out to have the highest count of the night. I don't remember how many bats we counted collectively, or what my total was. It was a great night and I hope we collected important data. I'm forever thankful I was able to be a part of it.

Monday, October 17, 2022

Firefly Watch 2022

The 2022 season of Firefly Watch was the most disappointing so far. There was a dramatic decrease in the number of flashes counted from 2021, which was a decrease from the previous season. Run by Mass Audubon, Firefly Watch monitors populations of fireflies nationwide, using citizen science observations. Observation protocols are simple. Count how many flashes you see in three separate ten second periods. I space mine ten minutes apart to get varying levels of darkness, starting just before sunset. We also record the flash pattern (single, double, or triple flash for instance), start and end times, wind, precipitation, and temperature. For good measure, I also record the colors of the flashes. I start at the end of May and depending on how long I keep seeing fireflies, I go until late August or early September. I use the same location every year to track the same population, and try to stick to the same dates every year. This year the dates for my second observation of the week were a day later than last year. I end the season when I go two consecutive observations with no fireflies. The latest I ended was September 26 in 2018. This year I ended on August 24, the first time I didn't make it into September. The last firefly I saw was August 7, so I actually went beyond the two night standard. 2022 saw a decrease of 94 flashes from 2021, nearly a 16% drop. That's close to 30% fewer than 2020, the highest count so far. The charts below show the population trends. Chart 1 shows each year's counts by date and how the number of flashes observed changes within the season. Chart 2 shows each year's total counts side by side.
While I could use rainy nights in 2021 as a partial explanation for the decreased count, I only had rain during one or two observations this year. This summer was abnormaly dry, but not quite a drought. Not enough rain could be a possible cause. Other factors include light pollution, although the amount of light is unchanged year to year, and pesticide use, but I have no way to measure who is using what pesiticides in the neighborhood. One final explanation is that the neighbors cleared some vegetation from their small woodlot in the back yard. I'll continue monitoring and hopefully the negative trend will reverse itself.

Monday, November 8, 2021

Firefly Watch 2021

Just because I haven't been writing this year doesn't mean I haven't been doing nothing this whole time. I completed my 4th season of Firefly Watch. This program is run by Massachusetts Audubon, but anyone anywhere can participate. 

Observation protocols are simple. Count how many flashes you see in three separate ten second periods. I space mine ten minutes apart to get varying levels of darkness, starting just before sunset. We also record the flash pattern (single, double, or triple flash for instance), start and end times, wind, precipitation, and temperature. For good measure, I also record the colors of the flashes. I start at the end of May and depending on how long I keep seeing fireflies, I go until late August or early September. I use the same location every year to track the same population, and try to stick to the same dates every year.

2020 saw an increase over the previous year and 2019 saw a slight decrease, with 2018 being the initial and baseline year. 2021 was the first year to see a significant decline in the number of flashes. Not only was it lower than last year's total, it was the lowest of all four years. In 2020 I counted 708 flashes. In 2021 I counted 593, a 16% decrease. 

I have no explanation for the drop. There were a few more rainy nights when I was doing observations in the previous years, and that may have grounded some of the fireflies. One night early in the season there was a thunderstorm with heavy rain and gusty wind and no one was flying that night. But in the previous three years I counted a grand total of 17 flashes on that date. While rain may account for some missing fireflies, it still leaves quite a void. Hopefully 2022 will see a rebound.

Year by year comparison of flash counts

Flashes by date