ABSTRACT: A survey of 31 Florida spring‐runs was conducted to estimate their submerged macrophyte standing crop and primary productivity. The standing crops of submerged vegetation were not significantly (p > 0.05) correlated to either total nitrogen (r = 0) or total phosphorus (r =−0.20) concentrations, but standing crops were significantly (p < 0.01) correlated to the percentage of the spring‐run's water surface shaded by marginal vegetation (r =−0.76). Maximum daily rates of primary productivity were positively correlated with average submerged macrophyte standing crops (r = 0.81; p < 0.001) and inversely correlated with the degree of shading by marginal vegetation (r =− 0.43; p < 0.05).
In this article, we examine the air‐sea exchange of exchangeable organic carbon (OC) as well as the internal pools and sources within a subarctic fjord. Air‐water fluxes of OC ranged from an uptake of 22 ± 10 mmol C m −2 d −1 in winter to a release of 2 ± 8 mmol C m −2 d −1 in the fall, sizable compared to that of CO 2 (average uptake of 136 mmol C m −2 d −1 for the fall and 2.6 ± 0.84 mmol C m −2 d −1 in the winter). The water column profiles of exchangeable dissolved organic carbon (EDOC) followed closely those of dissolved organic carbon (DOC), and EDOC represented, on average, about one‐third of DOC. The dynamic characteristic and active cycling of EDOC was evidenced by incubation experiments performed on each fjord compartment (sediment, water column, macroalgae) where sediments and macroalgae were found to be substantial sources and the water column acted as a strong sink of EDOC.
Studies in the marine environment require devices to gather data in remote locations. These devices commonly use some form of data logging that require the user to retrieve the device after a period of time. This is not only a large effort, but often presents an unnecessary delay and risk in the event that the device malfunctions, goes missing or if the data collected is redundant. We propose a modular, remote and autonomous sensing solution that enables multi-sensor readout and wireless data communication, providing scientists with real time data. This sensor buoy is comprised of a primary module which is a data logger that connects to an online server via mobile network. The secondary portion is the hub that connects to an array of sensors that are customized to the needs of the marine scientists.
The analysis of animal movement from telemetry data provides insights into how and why animals move. While traditional approaches to such analysis mostly focus on predicting animal states during movement, we describe an approach that allows us to identify representative movement patterns of different animal groups. To do this, we propose a carefully designed recurrent neural network and combine it with telemetry data for automatic feature extraction and identification of non-predefined representative patterns. In the experiment, we consider a particular marine predator species, the southern elephant seal, as an example. With our approach, we identify that the male seals in our data set share similar movement patterns when they are close to land. We identify this pattern recurring in a number of distant locations, consistent with alternative approaches from previous research.
MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 130:147-155 (1996) - doi:10.3354/meps130147 Herbivory on Posidoniaoceanica: magnitude and variability in the Spanish Mediterranean Cebrián J, Duarte CM, Marbà N, Enríquez S, Gallegos M, Olesen B We examined the leaf age dependence, magnitude and variability of herbivore consumption of Posidoniaoceanica (L.) Delile leaves in the Spanish Mediterranean. Two patterns of herbivore consumption along the life-span of P. oceanica leaves were found, namely a linear and a parabolic curve of cumulative leaf consumption versus leaf age, which are indicative of leaf-age-independent consumption rates and preference for mid-aged leaves, respectively. The fish Boopssalpa contributed about 75% to the total herbivore consumption, and seemed to be responsible for the parabolic pattern of consumption with leaf age. Herbivory appeared to be a minor factor in the control of P. oceanica production since it only accounted, on the average, for about 2% of its leaf production. This percentage tends to increase in the northern populations of the Spanish Mediterranean as a result of the longer leaf life-span and associated higher cumulative consumption values, and the lower leaf production of these populations. It is concluded that, in spite of the low levels of herbivory on P.oceanica in the Mediterranean, this seagrass supports a high herbivore production due to its large primary production. Herbivory . Posidoniaoceanica . Boopssalpa . Spanish Mediterranean Full text in pdf format PreviousNextExport citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 130. Publication date: January 11, 1996 Print ISSN:0171-8630; Online ISSN:1616-1599 Copyright © 1996 Inter-Research.
Abstract. The metabolic balance of the open waters supporting submerged macrophytes of the Doñana marsh (SW Spain) was investigated in spring, when community production is highest. The marsh community was net autotrophic with net community production rates averaging 0.61 g C m−2 d−1, and gross production rates exceeding community respiration rates by, on average, 43%. Net community production increased greatly with increasing irradiance, with the threshold irradiance for communities to become net autotrophic being 42 to 255 μE m−2 s−1, below which communities became net heterotrophic. Examination of the contributions of the benthic and the pelagic compartments showed the pelagic compartment to be strongly heterotrophic (average P/R ratio = 0.27), indicating that the metabolism of the pelagic compartment is strongly subsidised by excess organic carbon produced in the strongly autotrophic benthic compartment (average P/R = 1.58).
Abstract Rising temperatures in the Arctic Ocean are causing sea ice and glaciers to melt at record breaking rates, which has consequences for carbon cycling in the Arctic Ocean that are yet to be fully understood. Microbial carbon cycling is driven by internal processing of in situ produced organic carbon (OC), however recent research suggests that melt water from sea ice and glaciers could introduce an allochthonous source of OC to the microbial food web with ramifications for the metabolic balance of plankton communities. In this study, we characterized autochthonous and allochthonous sources of OC to the Western Svalbard fjord system using stable isotopes of carbon. We quantified δ 13 C of eukaryotic and prokaryotic planktonic groups using polar lipid‐derived fatty acids as biomarkers in addition to measuring δ 13 C of marine particulate OC and dissolved OC from glacial runoff. δ 13 C of bacteria (−22.5‰) was higher than that of glacial runoff OC (−28.5‰) and other phytoplankton groups (−24.7 to −29.1‰), which suggests that marine bacteria preferentially use a third source of OC. We present a Bayesian three‐source δ 13 C mixing model whereby ∼ 60% of bacteria carbon is derived from OC in sea ice, and the remaining carbon is derived from autochthonous production and glacial‐derived OC. These results suggest that subsidies of OC from melting glaciers will not likely influence microbial carbon cycling in Svalbard fjords in the future and that further research is needed to determine the effects of melting sea ice on microbial carbon cycling in fjord systems and elsewhere in the Arctic Ocean.
