CPOM Mass Data and Analysis for WL and LPP
Collected by: Kenneth Fortino, Leanna Tacik, and Carly Martin
Collected on:
- Wilkes Lake – 20 Feb 2013
- Lancer Park Pond – 20 March 2013
Affiliation: Longwood University
Location:
- Wilkes Lake – Samples were collected to the E of the island approximately equidistant from the N and S shore of the lake and about 20 m from the S shore.
- Lancer Park Pond – Samples were collected in the approximate middle of the lake and in the SW corner of the pond about 1 m from the S shore
Description:
Three replicate samples were collected with an Ekman dredge and then washed through a 250μm mesh in the field and preserved in 70% ethanol.
Back in the lab the preserved samples were washed through a 1 mm sieve. For WL the material retained by the sieve was dried in a pre-weighed weigh boat at 50o C for at least 48h before massing. For LPP the material retained by the sieve was collected in a pre-weighed paper lunch bag and dried for at least 48 h before massing.
Created: 12 April 2013
Modified: 12 April 2013
Variables:
- lake = the name of the lake
- WL = Wilkes Lake
- LPP = Lance Park Pond
- samp = the type of sample
- open = away from the shore
- lit = littoral, near shore
-
repl = the replicate
-
depth = the water depth where the sample was collected (m)
-
cruc.num = the name of the crucible
-
cruc.mass = the mass of the empty crucible (g)
-
cruc.sed = the mass of the crucuble and the dry sediment (g)
-
cruc.ash = the mass of the crucible and ashed (550o C for 4h) sediment (g)
-
sed = the mass of the dry sediment in crucible (g)
-
ash = the mass of the ashed sediment in crucible (g)
-
OM = the mass of the organic matter in crucible (g)
-
perc.OM = the percent organic matter in the sediment
-
boat.bag.num = the name of the pre-weighed weighboat or paper pag
-
boat.bag.mass = the mass of the empty weighboat or paper bag (g)
-
boat.bag.CPOM = the mass of the weighboat + the dried CPOM (g)
-
CPOM.ekman = the mass of the dry CPOM (g / 0.0225 m2)
-
CPOM = the mass of the dry CPOM (g / m2)
R Code
# Import LOI data to add CPOM data
WL.LPP.LOI.sp13 <- read.delim("./data/WL_LPP_LOI_sp13.txt", header = T, sep = " ", stringsAsFactors = F)
# Create variable for CPOM
# note these data replace the data in WL_CPOM_20Feb2013.md
boat.bag.num <- c(27, 72, 57, 28, 53, 66, 4, 5, 6, 1, 2, 3)
boat.bag.mass <- c(1.6925, 1.8084, 1.7482, 1.9434, 1.8294, 1.8443, 7.1048, 7.0473, 7.1103, 7.0334, 6.9891, 7.1693)
boat.bag.CPOM <- c(1.8544, 2.204, 2.0725, 2.4342, 2.4063, 2.5529, 12.3407, 9.0054, 8.4776, 36.5694, 12.7007, 23.0556)
CPOM.ekman <- boat.bag.CPOM - boat.bag.mass
# convert from g / 0.0225 m^2^ to g / m^2^
CPOM <- CPOM.ekman / 0.0225
# Create data.frame of all OM data from WL LPP spring 2013 sampling
WL.LPP.OM.sp13 <- data.frame(WL.LPP.LOI.sp13, boat.bag.num, boat.bag.mass, boat.bag.CPOM, CPOM.ekman, CPOM)
# Save data table
write.table(WL.LPP.OM.sp13, file = "./data/WL_LPP_OM_sp13.txt", row.names = F, quote = F)
Data
> WL.LPP.OM.sp13
lake samp repl depth cruc.num cruc.mass cruc.sed cruc.ash sed ash
1 WL open A 2.0 1 13.1339 16.1084 16.0627 2.9745 2.9288
2 WL open B 2.0 2 12.6351 16.9807 16.7785 4.3456 4.1434
3 WL open C 2.0 3 13.0659 14.1274 14.0378 1.0615 0.9719
4 WL lit A 1.9 4 12.2410 13.4951 13.3678 1.2541 1.1268
5 WL lit B 1.9 5 12.9951 14.9187 14.7305 1.9236 1.7354
6 WL lit C 1.9 6 11.9876 13.2359 13.1089 1.2483 1.1213
7 LPP open A 1.0 7 12.1973 13.1231 13.0049 0.9258 0.8076
8 LPP open B 1.0 8 12.5987 14.3463 14.1463 1.7476 1.5476
9 LPP open C 1.0 9 11.6665 13.0951 12.9363 1.4286 1.2698
10 LPP lit A 1.1 10 12.9349 13.5505 13.4565 0.6156 0.5216
11 LPP lit B 1.1 11 11.8880 12.7876 12.6797 0.8996 0.7917
12 LPP lit C 1.1 12 11.7819 12.1739 12.1200 0.3920 0.3381
perc.OM boat.bag.num boat.bag.mass boat.bag.CPOM CPOM.ekman CPOM
1 1.536393 27 1.6925 1.8544 0.1619 7.195556
2 4.652982 72 1.8084 2.2040 0.3956 17.582222
3 8.440886 57 1.7482 2.0725 0.3243 14.413333
4 10.150706 28 1.9434 2.4342 0.4908 21.813333
5 9.783739 53 1.8294 2.4063 0.5769 25.640000
6 10.173836 66 1.8443 2.5529 0.7086 31.493333
7 12.767336 4 7.1048 12.3407 5.2359 232.706667
8 11.444266 5 7.0473 9.0054 1.9581 87.026667
9 11.115778 6 7.1103 8.4776 1.3673 60.768889
10 15.269656 1 7.0334 36.5694 29.5360 1312.711111
11 11.994220 2 6.9891 12.7007 5.7116 253.848889
12 13.750000 3 7.1693 23.0556 15.8863 706.057778
>
Analysis
Relationship between CPOM, lake, and sample location
Due to non-homogeneity in the variance the CPOM mass was ln transformed
# SD in CPOM across samp
tapply((WL.LPP.OM.sp13$CPOM), WL.LPP.OM.sp13$samp, sd)
lit open
522.8097 85.5926
tapply(log(WL.LPP.OM.sp13$CPOM), WL.LPP.OM.sp13$samp, sd)
lit open
1.815811 1.302288
# SD in CPOM across lake
tapply(WL.LPP.OM.sp13$CPOM, WL.LPP.OM.sp13$lake, sd)
LPP WL
485.471298 8.574693
tapply(log(WL.LPP.OM.sp13$CPOM), WL.LPP.OM.sp13$lake, sd)
LPP WL
1.1783661 0.5225174
After transformation the CPOM mass was significantly greater in LPP and in the littoral samples and there was no interaction between the factors.
# 2-way ANOVA of CPOM mass ln transformed by lake * sample location
anova(lm(log(CPOM) ~ as.factor(lake) * as.factor(samp), data = WL.LPP.OM.sp13))
> anova(lm(log(CPOM) ~ as.factor(lake) * as.factor(samp), data = WL.LPP.OM.sp13))
Analysis of Variance Table
Response: log(CPOM)
Df Sum Sq Mean Sq F value Pr(>F)
as.factor(lake) 1 21.3718 21.3718 59.9653 5.516e-05 ***
as.factor(samp) 1 4.7140 4.7140 13.2266 0.006619 **
as.factor(lake):as.factor(samp) 1 0.7427 0.7427 2.0838 0.186865
Residuals 8 2.8512 0.3564
jpeg("./output/plots/CPOM_by_lake_samp_sp13.jpg")
par(las = 1)
plot(log(CPOM) ~ as.factor(samp), data = WL.LPP.OM.sp13, subset = lake == "WL", ylim=c(0, 7), col = "green")
plot(log(CPOM) ~ as.factor(samp), data = WL.LPP.OM.sp13, subset = lake == "LPP", add = T, col = "brown")
legend(0.5, 1.5, c("WL", "LPP"), pch=16, col=c("green", "brown"))
dev.off()
pdf("./output/plots/CPOM_by_lake_samp_sp13.pdf")
plot(log(CPOM) ~ as.factor(samp), data = WL.LPP.OM.sp13, subset = lake == "WL", ylim=c(0, 7), col = "green")
plot(log(CPOM) ~ as.factor(samp), data = WL.LPP.OM.sp13, subset = lake == "LPP", add = T, col = "brown")
legend(0.5, 1.5, c("WL", "LPP"), pch=16, col=c("green", "brown"))
dev.off()
