scholarly journals Diel and Seasonal Variability in Kelp Forest Soundscapes Off the Southern California Coast

2021 ◽  
Vol 8 ◽  
Author(s):  
Jack Butler ◽  
Camille M. L. S. Pagniello ◽  
Jules S. Jaffe ◽  
P. Ed Parnell ◽  
Ana Širović
Keyword(s):  
Seasonal Variability ◽  
Southern California ◽  
Marine Reserve ◽  
Kelp Forest ◽  
Acoustic Energy ◽  
Kelp Forests ◽  
Seasonal Periodicity ◽  
Frequency Bands ◽  
Marine Habitats ◽  
Vessel Noise

Soundscape ecology is a relatively new field that can provide insights into the structure and health of marine habitats. Though this field is growing, the acoustics of many marine habitats, including the giant kelp forests off Southern California, remain poorly studied. Here, we examine the diel and seasonal periodicity of kelp forest soundscapes within a protected and unprotected site off San Diego, CA. Singular value decomposition was used to identify frequency bands of interest, enabling tracking of these bands through seasons to examine their variability. Four frequency bands were identified: (1) 60–130 Hz, which encompassed a putative fish chorus, (2) 300–500 Hz, which encompassed a different putative fish chorus, (3) a band that encompassed humming generated by Plainfin Midshipmen Poricthys notatus (fundamental frequency: 85–95 Hz, and two subharmonics 175–185 Hz and 265–275 Hz), and (4) a band that encompassed the snaps of snapping shrimps from 2.5 to 7.5 kHz. Overall, kelp forest soundscapes exhibited diel and seasonal variability. In particular, the two putative fish choruses dominated the dusk soundscapes during late spring and summer, and the Midshipmen hums persisted throughout nights in summer. Snapping shrimp sounds exhibited stereotypic crepuscular activity, with peaks in acoustic energy in the 2.5–7.5 kHz band occurring at dusk and dawn. In addition, vessel noise was identified and found to exhibit strong seasonal and spatial variation. Vessel noise was greatest during August and September at the protected site and was generally lower during the winter and spring months. These findings help establish reference acoustic indices for the kelp forests off Southern California, within and outside of a protected area, and can provide resource managers with information on how well a marine reserve protects a species of interest, as well as the putative human visitation of these protected areas.

scholarly journals Four new Scopalina from Southern California: the first Scopalinida (Porifera: Demospongiae) from the temperate Eastern Pacific

Zootaxa ◽  
2021 ◽  
Vol 4970 (2) ◽  
pp. 353-371
Author(s):  
THOMAS L. TURNER
Keyword(s):  
New Species ◽  
Southern California ◽  
Forest Ecosystems ◽  
Kelp Forest ◽  
Eastern Pacific ◽  
Kelp Forests ◽  
Sponge Diversity ◽  
Ecological Importance

Sponges (phylum Porifera) are common inhabitants of kelp forest ecosystems in California, but their diversity and ecological importance are poorly characterized in this biome. Here I use freshly collected samples to describe the diversity of the order Scopalinida in California. Though previously unknown in the region, four new species are described here: Scopalina nausicae sp. nov., S. kuyamu sp. nov., S. goletensis sp. nov., and S. jali sp. nov.. These discoveries illustrate the considerable uncharacterized sponge diversity remaining in California kelp forests, and the utility of SCUBA-based collection to improve our understanding of this diversity. 

scholarly journals Four new Scopalina from Southern California: the first Scopalinida (Porifera: Demospongiae) from the Eastern Pacific

2020 ◽  
Author(s):  
Thomas L. Turner
Keyword(s):  
New Species ◽  
Pacific Ocean ◽  
Southern California ◽  
Forest Ecosystems ◽  
Kelp Forest ◽  
Eastern Pacific ◽  
Kelp Forests ◽  
Eastern Pacific Ocean ◽  
Sponge Diversity ◽  
Ecological Importance

AbstractSponges (phylum Porifera) are common inhabitants of kelp forest ecosystems in California, but their diversity and ecological importance are poorly characterized in this biome. Here I use freshly collected samples to describe the diversity of the order Scopalinida in California. Though previously unknown in the Eastern Pacific Ocean, four new species are described here: Scopalina nnnn1 sp. nov., S. kkkk sp. nov., S. gggg sp. nov., and S. jjjj sp. nov.. These discoveries illustrate the considerable uncharacterized sponge diversity remaining in California kelp forests, and the utility of SCUBA-based collection to improve our understanding of this diversity.

Mechanisms leading to recruitment inhibition of giant kelp Macrocystis pyrifera by an understory alga

2021 ◽  
Vol 657 ◽  
pp. 59-71
Author(s):  
BA Beckley ◽  
MS Edwards
Keyword(s):  
Field Experiments ◽  
Local Community ◽  
Kelp Forest ◽  
Macrocystis Pyrifera ◽  
Forest Recovery ◽  
Kelp Forests ◽  
Giant Kelp ◽  
Combined Effects ◽  
Life Stages ◽  
Survival And Growth

The forest-forming giant kelp Macrocystis pyrifera and the communities it supports have been decreasing across their native ranges in many parts of the world. The sudden removal of giant kelp canopies by storms increases space and light for the colonization by understory macroalgae, such as Desmarestia herbacea, which can inhibit M. pyrifera recovery and alter local community composition. Understanding the mechanisms by which algae such as D. herbacea interact with M. pyrifera can provide insight into patterns of kelp forest recovery following these disturbances and can aid in predicting future community structure. This study experimentally tested the independent and combined effects of two likely competitive mechanisms by which D. herbacea might inhibit recovery of M. pyrifera in the Point Loma kelp forest in San Diego, California (USA). Specifically, we conducted field experiments to study the individual and combined effects of shade and scour by D. herbacea on the survival of M. pyrifera microscopic life stages, and the recruitment, survival, and growth of its young sporophytes. Our results show that scour had the strongest negative effect on the survival of M. pyrifera microscopic life stages and recruitment, but shade and scour both adversely affected survival and growth of these sporophytes as they grew larger. Canopy-removing storms are increasing in frequency and intensity, and this change could facilitate the rise of understory species, like D. herbacea, which might alter community succession and recovery of kelp forests.

scholarly journals Valuation of kelp forest ecosystem services in the Falkland Islands: A case study integrating blue carbon sequestration potential

One Ecosystem ◽  
2021 ◽  
Vol 6 ◽  
Author(s):  
Daniel Bayley ◽  
Paul Brickle ◽  
Paul Brewin ◽  
Neil Golding ◽  
Tara Pelembe
Keyword(s):  
Ecosystem Services ◽  
Kelp Forest ◽  
Blue Carbon ◽  
Falkland Islands ◽  
Kelp Forests ◽  
Storm Damage ◽  
Ecological Processes ◽  
True Value ◽  
Sequestration Potential

Kelp forests provide many important ecosystem services to people, including mitigating storm damage, cycling nutrients, and providing commercially-harvestable resources. However, kelp forests’ ability to sequester carbon dioxide, and therefore help regulate the climate, has until recently, been overlooked in assessments of the beneficial services they provide. In this study we incorporate updated knowledge on the potential of kelp to sequester ‘blue carbon’, and use the extensive kelp forests of the Falkland Islands as a case study to assess the value of kelp forest to society through multiple associated ecosystem services. Our analysis shows kelp forests provide a highly valuable range of direct and indirect services, which if managed correctly, will continue to benefit people, both now and in the future. The total estimated value of the Falkland Islands’ kelp system is currently equivalent to ~ £2.69 billion per year (or £3.24 million km-2 year-1). However, the true value of the kelp forest surrounding the Falkland Islands is likely to be higher still, given that our estimate does not account for elements such as associated scientific research, tourism, and cultural services, due to the necessary data currently being unavailable. Similarly, the full value of these highly biodiverse ecosystems in supplying habitat and food to a large range of associated species is crucial, yet extremely difficult to fully quantify. This study illustrates the importance of maintaining kelp ecosystems in a healthy state to ensure they continue to supply valuable ecological processes, functional roles, and ecosystem services, including their overlooked role as significant long-term carbon sinks.

scholarly journals Disturbance intensity, disturbance extent and ocean climate modulate kelp forest understory communities

2020 ◽  
Vol 651 ◽  
pp. 57-69
Author(s):  
T Wernberg ◽  
M Couraudon-Réale ◽  
F Tuya ◽  
M Thomsen
Keyword(s):  
Functional Groups ◽  
Kelp Forest ◽  
Forest Understory ◽  
Small Scale ◽  
Kelp Forests ◽  
Ocean Climate ◽  
Disturbance Regimes ◽  
Disturbance Intensity ◽  
Control Community ◽  
Understory Communities

Disturbances often control community structure by removing large dominant species, allowing new species to colonize. Disturbances vary in intensity and extent, and their effects on resident communities can depend on local environmental conditions. We tested the effects of disturbance intensity and extent on different functional groups of understory species in kelp forests at 4 locations along an ocean climate gradient in Western Australia. We hypothesized that, compared to intact canopies, increasing disturbance intensities (50 and 100% of kelp removal) and extents (2, 4 and 8 m diameter) would promote light-dependent competitors (turf, foliose, articulated coralline and fucoid seaweeds) at the expense of less light-dependent functional groups (invertebrates and encrusting seaweeds). We also hypothesized that these effects would be most pronounced at warmer relative to cooler locations, where metabolic and ecological rates are faster. The first hypothesis was supported; light-dependent understory groups (turfs, in particular) increased, while less light-dependent groups (crusts in particular) decreased with increasing disturbance regimes. However, the second hypothesis was not supported; even though understory communities differed between locations and turf covers were highest at the warmest location, we found no significant interactions between locations and disturbance regimes. Importantly, our results revealed that even small-scale partial canopy loss can have significant effects on kelp-associated communities. The implied community-wide, density-dependent effects have implications for the management and conservation of kelp forests, because restoration of ecological functions must also consider the density of kelp forests, not simply their presence or absence.

scholarly journals Kelp forest ecosystems: biodiversity, stability, resilience and future

2002 ◽  
Vol 29 (4) ◽  
pp. 436-459 ◽  
Author(s):  
Robert S. Steneck ◽  
Michael H. Graham ◽  
Bruce J. Bourque ◽  
Debbie Corbett ◽  
Jon M. Erlandson ◽  
...  
Keyword(s):  
Case Studies ◽  
Sea Urchin ◽  
North Atlantic ◽  
Forest Ecosystems ◽  
Kelp Forest ◽  
Kelp Forests ◽  
Apex Predators ◽  
The Past ◽  
The North ◽  
Fishing Impacts

Kelp forests are phyletically diverse, structurally complex and highly productive components of coldwater rocky marine coastlines. This paper reviews the conditions in which kelp forests develop globally and where, why and at what rate they become deforested. The ecology and long archaeological history of kelp forests are examined through case studies from southern California, the Aleutian Islands and the western North Atlantic, well-studied locations that represent the widest possible range in kelp forest biodiversity. Global distribution of kelp forests is physiologically constrained by light at high latitudes and by nutrients, warm temperatures and other macrophytes at low latitudes. Within mid-latitude belts (roughly 40–60° latitude in both hemispheres) well-developed kelp forests are most threatened by herbivory, usually from sea urchins. Overfishing and extirpation of highly valued vertebrate apex predators often triggered herbivore population increases, leading to widespread kelp deforestation. Such deforestations have the most profound and lasting impacts on species-depauperate systems, such as those in Alaska and the western North Atlantic. Globally urchin-induced deforestation has been increasing over the past 2–3 decades. Continued fishing down of coastal food webs has resulted in shifting harvesting targets from apex predators to their invertebrate prey, including kelp-grazing herbivores. The recent global expansion of sea urchin harvesting has led to the widespread extirpation of this herbivore, and kelp forests have returned in some locations but, for the first time, these forests are devoid of vertebrate apex predators. In the western North Atlantic, large predatory crabs have recently filled this void and they have become the new apex predator in this system. Similar shifts from fish- to crab-dominance may have occurred in coastal zones of the United Kingdom and Japan, where large predatory finfish were extirpated long ago. Three North American case studies of kelp forests were examined to determine their long history with humans and project the status of future kelp forests to the year 2025. Fishing impacts on kelp forest systems have been both profound and much longer in duration than previously thought. Archaeological data suggest that coastal peoples exploited kelp forest organisms for thousands of years, occasionally resulting in localized losses of apex predators, outbreaks of sea urchin populations and probably small-scale deforestation. Over the past two centuries, commercial exploitation for export led to the extirpation of sea urchin predators, such as the sea otter in the North Pacific and predatory fishes like the cod in the North Atlantic. The large-scale removal of predators for export markets increased sea urchin abundances and promoted the decline of kelp forests over vast areas. Despite southern California having one of the longest known associations with coastal kelp forests, widespread deforestation is rare. It is possible that functional redundancies among predators and herbivores make this most diverse system most stable. Such biodiverse kelp forests may also resist invasion from non-native species. In the species-depauperate western North Atlantic, introduced algal competitors carpet the benthos and threaten future kelp dominance. There, other non-native herbivores and predators have become established and dominant components of this system. Climate changes have had measurable impacts on kelp forest ecosystems and efforts to control the emission of greenhouse gasses should be a global priority. However, overfishing appears to be the greatest manageable threat to kelp forest ecosystems over the 2025 time horizon. Management should focus on minimizing fishing impacts and restoring populations of functionally important species in these systems.

Mass mortality of a dominant kelp (Laminariales) at Goat Island, north-eastern New Zealand

1996 ◽  
Vol 47 (7) ◽  
pp. 907 ◽  
Author(s):  
RG Cole ◽  
RC Babcock
Keyword(s):  
New Zealand ◽  
Marine Reserve ◽  
Kelp Forest ◽  
Austral Summer ◽  
Mass Mortality ◽  
Ecklonia Radiata ◽  
Rocky Reefs ◽  
North Eastern ◽  
Mass Mortalities

In north-eastern New Zealand, monospecific stands of the laminarian Ecklonia radiata occupy rocky reefs at depths below 10 m on exposed shores. In the austral summer of 1992-93, mass mortalities of populations of E. radiata in the Cape Rodney to Okakari Point Marine Reserve near Leigh were recorded, in which 40-100% of the sporophytes at depths greater than 10 m died. Mortality was gradual, beginning with erosion of the laminae and ultimately progressing to the stipes, which eventually decayed. The mortality was first evident in the deepest plants and culminated in the elimination of large areas of kelp forest. The event was not associated with any previously reported mortality agents. Investigations of the effects of the mortality on other organisms are continuing.

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